tag:theconversation.com,2011:/institutions/agricultural-research-council-2725/articlesAgricultural Research Council2024-02-13T15:04:44Ztag:theconversation.com,2011:article/2221072024-02-13T15:04:44Z2024-02-13T15:04:44Z17 million South Africans live on communal land – new study of a rural valley offers insights on how to manage it<figure><img src="https://images.theconversation.com/files/572398/original/file-20240131-19-f7h2o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tyhume Valley in Eastern Cape, South Africa.</span> <span class="attribution"><span class="source">Wonga Masiza</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The Tyhume River, flowing from the forested Amathole Mountains in South Africa’s Eastern Cape province, gives its name to a valley of 20 villages on communal land. Much of the land is being used to keep livestock, as crop production has declined over the years. This land is <a href="https://www.sciencedirect.com/science/article/abs/pii/S0264837712001998?via%3Dihub">under the custodianship of traditional leaders</a>.</p>
<p>The valley is typical of South Africa’s communal land: affected by <a href="https://doi.org/10.2989/10220119.2022.2138973">soil erosion</a>, <a href="https://www.tandfonline.com/doi/abs/10.1080/00207233.2021.1886557">bush encroachment</a> and <a href="http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0301-603X2022000200005">water scarcity</a>. </p>
<p>About one third (over 17 million) of <a href="https://www.parliament.gov.za/storage/app/media/Pages/2017/october/High_Level_Panel/Commissioned_Report_land/Commisioned_Report_on_Tenure_Reform_LARC.pdf">South Africa’s population lives on communal land</a>, which makes up around <a href="https://sarpn.org/documents/d0002695/index.php">13%</a> of all land in the country. The <a href="https://www.gov.za/sites/default/files/gcis_document/201707/40965gen510.pdf">Communal Land Tenure Bill, 2017</a> defines communal land as “owned, occupied or used by members of a community subject to shared rules or norms and customs”. It can also be owned by the state.</p>
<p>This land can benefit rural communities by providing ecosystem goods and services, such as shelter, water, fuelwood, food and cultural amenities. But natural processes and human activity can transform the land. </p>
<p>Unmonitored and poorly managed land changes can trigger soil erosion, overgrazing, loss of biodiversity and water scarcity. In South Africa, communal land is considered to be <a href="https://doi.org/10.1002/pan3.10260">more degraded than privately owned land</a>. This can negatively affect the livelihoods of people who derive ecosystem services from it.</p>
<p>Common indicators and causes of land degradation are generally understood. But less is known about how people living in communal lands interpret land changes and their impact. It’s unclear what they perceive as land degradation or which kinds of land changes matter most to them. This helps explain the lack of sound policies and practical strategies to rehabilitate land.</p>
<p>Our team of geoinformation scientists at South Africa’s Agricultural Research Council and the University of the Free State carried out <a href="https://www.frontiersin.org/articles/10.3389/fcosc.2023.1205750/full">a study</a> which mapped land use and land cover change in the Tyhume Valley over 30 years. </p>
<p>To understand the extent, causes and impact of communal land change, we analysed a series of historical satellite images from 1989 to 2019 and conducted interviews with locals. Instead of interviewing experts and leaders, the study measured the most common perceptions among community members.</p>
<p>As far as we know, this study is one of the first in South Africa to combine satellite data and local perceptions. This offered a more complete view of communal land change, and valuable insights on its impacts. </p>
<p>We suggested some ways in which this land could be managed better to provide ecosystem services and livelihoods. </p>
<h2>Satellite imagery and community perceptions</h2>
<p>Our study set out to discover whether satellite-measured trends of land use and land cover corresponded with those perceived by the community. We also explored the causes, rate and impact of these trends.</p>
<p>Satellite imagery from 1989 to 2019 revealed increases of the sweet thorn tree (<em>Vachellia karroo</em>) by 25% and the residential area (2.5%). It showed declines of grazing land (18%), cropland (9.6%) and dams (1.1%). </p>
<p>Assisted by 102 long-standing residents, most above 50 years of age, we asked about the causes and impacts of the observed changes. </p>
<p>Most respondents (over 80%) noted the encroachment of the sweet thorn tree on grazing land and abandoned cropland. They said contributing factors were a decrease in fuelwood harvesting due to increased reliance on electricity, the abandonment of cropland (providing habitat for the sweet thorn) and seed dispersal caused by unrestricted movement of animals. Many saw the tree as beneficial because goats like to eat it and it makes good fuel. Others were concerned that this tree was invading productive agricultural land and causing a loss of biodiversity. They mentioned increased scarcity and disappearance of medicinal and culturally significant plants.</p>
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Read more:
<a href="https://theconversation.com/smallholder-crop-farming-is-on-the-decline-in-south-africa-why-it-matters-119333">Smallholder crop farming is on the decline in South Africa. Why it matters</a>
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<p>Most respondents noted a decrease in grazing land, cropland and surface water. As reasons, they cited lack of access control (poor management, allowing bush encroachment), lack of farmer support and equipment, and poor rainfall.</p>
<p>New houses had been erected on grazing land. This was seen as a result of population increase and inward migration. Livestock farmers saw this as a problem because they had to buy fodder or trek their cattle long distances to graze. The population increase also put strain on water resources.</p>
<p>Every village in the area had at least one communal dam that had dried up. Despite 14 years of below-average rainfall and a negative rainfall trend between 1989 and 2019, the trend was not statistically significant. The community perceived that water resources had declined because of overuse and poor maintenance of dams. They said the government no longer desilted community dams, and that the community had abandoned traditional practices such as the maintenance of surface water channels and homestead ponds. </p>
<p>They gave water scarcity as one of the main reasons that croplands had been abandoned.</p>
<p>Most said the communal lands were healthier and offered more resources when areas were fenced off and people had to get permits to use land. Local residents had <a href="https://link.springer.com/article/10.1007/s10745-006-9062-9">cut fences</a> to give their animals unlimited access to grazing and water.</p>
<p>Overall, the changes to the Tyhume Valley environment were not positive. The respondents said the decline in agricultural activity had resulted in increased unemployment and consumption of unhealthy food.</p>
<p>Similar changes have been reported on <a href="https://www.tandfonline.com/doi/abs/10.1080/03057070.2014.943525">many other communal lands</a>.</p>
<h2>Better land management</h2>
<p>The land can be better managed through interventions by village committees, tribal authorities and extension services, and by following spatial planning and land use guidelines.</p>
<p>The sweet thorn can be controlled by stocking more browsing animals. <a href="https://www.tandfonline.com/doi/abs/10.2989/10220119.2016.1178172">Studies</a> have demonstrated that this plant has a high nutritive value.</p>
<p>The community, with help from the government, needs to reinstate water harvesting practices and the regular desilting of dams. Other communal <a href="https://www.drdar.gov.za/restoreddamsreducelivestockmortality/">dam restoration projects</a> in the Eastern Cape have succeeded by dredging and augmentation of stock dams.</p>
<p>This study shows that the combination of <a href="https://theconversation.com/technique-developed-in-kenya-offers-a-refined-way-to-map-tree-cover-76709">satellite imagery</a> and local perceptions provides valuable insights about the extent, causes and impacts of land change in communal areas.</p><img src="https://counter.theconversation.com/content/222107/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wonga Masiza receives funding from Agricultural Research Council.</span></em></p>Satellite images and community perceptions combine to give a fuller picture of land use changes.Wonga Masiza, Researcher, Agricultural Research CouncilLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2100922023-07-20T14:15:44Z2023-07-20T14:15:44ZSurviving heat waves in Africa – three essential reads<figure><img src="https://images.theconversation.com/files/538513/original/file-20230720-15-nemax3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A man pours water on his head to cool off in Algiers, during a heat wave on 18 July 2023. </span> <span class="attribution"><span class="source">AFP via Getty Images</span></span></figcaption></figure><p>Around the world, temperature records are being broken in countries in Africa, Europe, America and Asia. The planet experienced its <a href="https://climatereanalyzer.org/clim/t2_daily/">hottest day</a> on record at the beginning of July 2023. </p>
<p>This is not totally unexpected. Scientists had warned that if the rise in global temperature was not limited to 1.5°C, the world could face a severe threat from extreme heat. As it is, the 1.5°C target seems unattainable. A recent <a href="https://www.unep.org/resources/emissions-gap-report-2022">UN report</a> did not see a credible pathway to achieving this goal. </p>
<p>In a <a href="https://theconversation.com/northern-europe-faces-biggest-relative-increase-in-uncomfortable-heat-and-is-dangerously-unprepared-new-research-209745">recent article</a> for The Conversation UK, scientists Jesus Lizana, Nicole Miranda and Radhika Khosla described how countries in the tropics would see the largest absolute increase in extreme heat if the global temperature rise moved from 1.5°C to 2°C. </p>
<p>In their <a href="https://www.researchgate.net/publication/372342472_Change_in_cooling_degree_days_with_global_mean_temperature_increasing_from_15_C_to_20_C">published research</a>, they indicated that countries in central and sub-Saharan Africa, such as the Central African Republic, Burkina Faso, Mali, South Sudan, Chad, Cameroon, Congo, Democratic Republic of Congo and Nigeria, would be hit the hardest.</p>
<p>Experts writing for The Conversation Africa have also touched on these issues and how to survive them. Here, we’ve collated three of these articles. </p>
<h2>1. Heat officer to the rescue</h2>
<p>Increasingly threatened by dangerous temperatures, Freetown, Sierra Leone’s capital, appointed a chief heat officer earlier in the year. </p>
<p>The chief heat officer – the first in Africa – has the responsibility of raising awareness about extreme heat, improving responses to heat waves, and collecting, analysing and visualising heat impact data for the city, which is home to <a href="https://populationstat.com/sierra-leone/freetown">1.2 million people</a>.</p>
<p>Architect and researcher Olumuyiwa Adegun explains that Sierra Leone had to take steps because in 2017, the Intergovernmental Panel on Climate Change <a href="https://chinadialogueocean.net/en/governance/19162-sea-level-rise-sierra-leone-sinking-islands/">ranked the west African country third</a>, after Bangladesh and Guinea Bissau, on its list of countries most vulnerable to climate change.</p>
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Read more:
<a href="https://theconversation.com/africas-first-heat-officer-is-based-in-freetown-5-things-that-should-be-on-her-agenda-199274">Africa's first heat officer is based in Freetown – 5 things that should be on her agenda</a>
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<h2>2. Knowing where and when it’s too hot in southern Africa</h2>
<p>Heat stress is not just uncomfortable; it can be dangerous. To create a detailed picture of when and where heat stress occurs in southern Africa, a group of scientists – Sarah Roffe, Adriaan van der Walt and Jennifer Fitchett – applied a human thermal comfort index to regional data. </p>
<p><a href="https://doi.org/10.1002/joc.8009">They found</a> that there has been a consistent change in thermal comfort – the human body’s experience of the outdoor thermal environment – from the 1970s to today. </p>
<p>Their findings confirm that southern Africans are experiencing heat stress more often than in 1979.</p>
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Read more:
<a href="https://theconversation.com/heat-stress-is-rising-in-southern-africa-climate-experts-show-where-and-when-its-worst-198455">Heat stress is rising in southern Africa – climate experts show where and when it’s worst</a>
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<h2>3. A vote for climate resilient primary healthcare</h2>
<p>Climate change events in Africa have implications not just for the environment but for people. Impacts include injuries, diseases and death. </p>
<p>Considering that climate events place the health systems of affected countries under strain, scientists Bob Mash and Christian Lueme Lokotola reviewed the level of preparedness of African primary healthcare systems. They found these systems were poorly prepared for the impacts of climate change. </p>
<p>The scientists then identified five key questions that health systems must answer in order to build more resilient primary healthcare in the face of climate change. </p>
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Read more:
<a href="https://theconversation.com/five-questions-for-african-countries-that-want-to-build-climate-resilient-health-systems-206783">Five questions for African countries that want to build climate-resilient health systems</a>
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<img src="https://counter.theconversation.com/content/210092/count.gif" alt="The Conversation" width="1" height="1" />
Temperature records are being broken in Africa and around the world.Adejuwon Soyinka, Regional Editor West AfricaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2048322023-05-10T13:22:45Z2023-05-10T13:22:45ZSouth Africa’s cold weather has arrived – some tips on how to stay warm and safe<figure><img src="https://images.theconversation.com/files/524611/original/file-20230505-21-1gxzfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When cold weather sets in there are several ways to keep yourself warm.</span> <span class="attribution"><span class="source">NickyLloyd/Getty Images</span></span></figcaption></figure><p>Research shows that the world is undoubtedly warming. And, as the global average temperature keeps rising, heatwaves are increasing in their <a href="https://www.nature.com/articles/s41467-020-16970-7">frequency, duration and intensity</a> for most of the world’s regions.</p>
<p>But that doesn’t mean cold weather will disappear entirely. While annual extreme cold events are becoming <a href="https://doi.org/10.1002/joc.6947">less frequent and less intense</a>, as you’d expect in a warming world, researchers suggest the climate systems that drive anomalously cold weather will continue to cause cold snaps <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2011GL047103">globally into the 21st century</a>. As we become more accustomed to a warmer world, we become less accustomed to these cold events, and therefore more vulnerable. </p>
<p>Being exposed to cold temperatures can increase the risk of hypothermia, frostbite, and other cold-related <a href="https://www.cdc.gov/niosh/topics/coldstress/coldrelatedillnesses.html#:%7E:text=Prolonged%20exposure%20to%20cold%20will,think%20clearly%20or%20move%20well">illnesses</a> like cardiovascular and respiratory diseases. That’s especially true for people who are homeless, live in poorly insulated homes, or who cannot warm their homes using heaters, hot water bottles and electric blankets.</p>
<p>As we’re writing this article, South Africa is heading into winter. The first cold fronts have already reached the country’s south-western regions of Cape Town and surrounds, and the interior has started to experience cooler weather. Rolling blackouts known as loadshedding exacerbate the situation; loadshedding is often <a href="https://www.esi-africa.com/features-analysis/loadshedding-in-winter-whats-that-going-to-be-like/">worst during the winter months</a> due to the heightened pressure on the electrical grid as people try to heat their homes and keep lights on during the longer hours of darkness.</p>
<p>As researchers who have been exploring extreme temperature events and thermal comfort in South Africa, we have some advice about how to keep yourself as warm as possible during the winter months.</p>
<h2>Our research</h2>
<p>South Africa is often marketed to tourists as a “<a href="https://theconversation.com/does-sunny-south-africa-really-have-an-ideal-climate-for-tourism-103852">sunny</a>” holiday destination. The country experiences <a href="https://www.tandfonline.com/doi/full/10.1080/09669582.2016.1251933?casa_token=xZYXtQLGv_wAAAAA%3AGeIX9-k_8LcCmQVK0oiDurB4INI-jHskbxGbAcHjDVwEmWUHrgrG01VtuoYkDl1Su5eVRx7tPRkp">warm summers and frequent clear skies</a>, providing an ideal destination for beach vacations. </p>
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Read more:
<a href="https://theconversation.com/does-sunny-south-africa-really-have-an-ideal-climate-for-tourism-103852">Does sunny South Africa really have an ideal climate for tourism?</a>
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<p>But its winters can be bitterly cold, particularly in the mountainous regions of the Drakensberg-Maloti and the Cape Fold Mountains, and in towns such as Sutherland in the Northern Cape province.</p>
<p>O<a href="https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/joc.6947">ur research</a> has explored trends in extreme climate events over the past six decades. </p>
<p>Using data from <a href="https://www.wcrp-climate.org/etccdi">indices developed by expert teams</a> from the World Meteorological Organisation, we have identified extreme cold events across South Africa’s nine provinces. Our research confirms that these events are occurring less often and for shorter periods than in previous decades. The duration of extreme cold events is decreasing at a rate of 1 day per decade; the number of these events is decreasing by 0.2 events per decade. </p>
<h2>Provincial trends</h2>
<p>However, for some locations in the Western Cape, Eastern Cape and North West provinces, these average trends do not hold true. Cold waves in these locations are increasing in duration. </p>
<p><a href="https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/joc.8009">An analysis</a> of the Universal Thermal Climate Index outputs for Southern Africa over the period 1979 to 2021 confirms that large areas of the South African interior still experience slight cold stress from June to August, while the high-lying mountainous regions experience moderate cold stress in the middle of each year. </p>
<p>There have been several newsworthy extreme cold events in recent years that have seen low temperatures and snowfall affecting various regions of the country. One, in March 2016, was unseasonal (South Africa’s winter months are June to August) – southern regions of the Western Cape experienced temperatures below -6°C, which is unusual for that time of the year.</p>
<p>In June and July 2019, Gauteng and the Western Cape experienced several cold fronts that led to consecutive cold days and nights and resulted in one reported casualty due to hypothermia in <a href="https://www.iol.co.za/the-star/news/one-more-freezing-night-gauteng-cold-front-to-end-wednesday-28418895">Dobsonville, Soweto</a> and one in <a href="https://www.iol.co.za/capetimes/news/homeless-man-freezes-to-death-on-sea-point-beach-30027920">Sea Point, Cape Town</a>. </p>
<p>In July 2021, a severe cold snap, caused by a succession of cold fronts making landfall over South Africa, resulted in <a href="https://www.news24.com/news24/southafrica/news/photos-south-africans-shiver-as-freezing-conditions-sweep-across-the-interior-20210723">record-breaking temperatures and snowfall</a> across many parts of the country, including the Western Cape, Eastern Cape, and KwaZulu-Natal. </p>
<p>These events are a reminder of how dangerous extreme cold can be. Here’s how you can mitigate its effects.</p>
<h2>Some tips</h2>
<p>First, it’s important to know your risks:</p>
<ul>
<li><p>Infants (younger than 1 year) lose body heat more easily than adults.</p></li>
<li><p>Adults over 65 are more susceptible to extremely cold temperatures due to their slow metabolisms and levels of physical activity.</p></li>
<li><p>People who spend longer periods outdoors, including homeless individuals, sportspeople and outdoor workers, are at increased risk for cold-related health problems. </p></li>
</ul>
<p>However, everyone should take precautions to prevent cold exposure and minimise the risk of cold stress. These include the following tips:</p>
<ul>
<li><p>Limit your time outdoors, where possible.</p></li>
<li><p>Dress warmly (thermal clothing, jerseys and closed shoes) and cover up exposed skin to reduce the risk of hypothermia.</p></li>
<li><p>Close windows and even use thicker curtains in the winter evenings to keep in the heat.</p></li>
<li><p>Identify and close gaps in doorways and window frames that could be letting in the cold.</p></li>
<li><p>Insulate homes and buildings to reduce the need for heating and retain any heat generated between loadshedding.</p></li>
<li><p>Intensify your physical activity.</p></li>
<li><p>Invest in some extra and thicker blankets.</p></li>
<li><p>Stay informed about the latest loadshedding schedules to ensure you can cook warm meals while the power is on.</p></li>
<li><p>Stay informed and monitor the local media about the latest weather updates and warnings.</p></li>
</ul>
<h2>Policy shifts</h2>
<p>In addition to these individual measures, broader policy solutions can help mitigate the impact of loadshedding during extreme cold weather. These include increasing investment in renewable energy, improving the electricity grid’s efficiency, and implementing targeted measures to support vulnerable populations and communities during loadshedding periods such as by providing shelters and soup kitchens.</p>
<p>While the push for these policies continues, make sure you dress in layers and stay indoors as much as you can this winter.</p><img src="https://counter.theconversation.com/content/204832/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adriaan Van Der Walt receives funding from the National Research Foundation, South Africa </span></em></p><p class="fine-print"><em><span>Jennifer Fitchett receives funding from GENUS: the DSI-NRF Centre of Excellence for Palaeosciences and the National Research Foundation. </span></em></p><p class="fine-print"><em><span>Sarah Roffe receives funding from the National Research Foundation, South Africa.</span></em></p>Climate systems which drive anomalously cold weather will still cause cold extreme events into the 21st century.Adriaan Van Der Walt, Senior Lecturer of Physical Geography and GIS, University of the Free StateJennifer Fitchett, Associate Professor of Physical Geography, University of the WitwatersrandSarah Roffe, Researcher, Agricultural Research CouncilLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1984552023-01-26T10:14:59Z2023-01-26T10:14:59ZHeat stress is rising in southern Africa – climate experts show where and when it’s worst<figure><img src="https://images.theconversation.com/files/506391/original/file-20230125-2999-tc5bml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Being too hot isn't just uncomfortable: it can be dangerous.</span> <span class="attribution"><span class="source">Angel DiBilio/Shutterstock</span></span></figcaption></figure><p>Most of us have felt either too hot or too cold at some point in our lives. Depending on where we live, we may feel too cold quite often each winter, and too hot for a few days in summer. As we’re writing this in late January 2023 many southern Africans are probably feeling very hot and fatigued; a prolonged regional heatwave began around 9 January.</p>
<p>Being too hot isn’t just uncomfortable. Heat stress causes dehydration, headaches, nausea – and, when people are exposed to high temperatures for protracted periods, they risk <a href="https://ehp.niehs.nih.gov/doi/full/10.1289/ehp.123-A275">severe health outcomes and could even die</a>. For instance, at least five people working on farms in South Africa’s Northern Cape province <a href="https://www.news24.com/news24/southafrica/news/we-were-struggling-to-breathe-five-farm-workers-died-of-heat-stroke-in-sweltering-northern-cape-20230122">have died from heat stroke</a> in January. At least <a href="https://www.nbcnews.com/science/environment/south-asias-intense-heat-wave-sign-things-come-rcna30239">90 people died in India and Pakistan</a> in May 2022 during a devastating heatwave.</p>
<p>The situation is only going to get worse. The United Nations’ Intergovernmental Panel on Climate Change <a href="https://www.ipcc.ch/report/ar6/wg2/about/frequently-asked-questions/keyfaq3/">warns</a> that “globally, the percentage of the population exposed to deadly heat stress is projected to increase from today’s 30% to 48%-76% by the end of the century, depending on future warming levels and location”.</p>
<p>We wanted to create a detailed picture of when and where heat stress occurs in southern Africa. By applying a global gridded dataset of a human thermal comfort index, <a href="https://doi.org/10.1002/joc.8009">we found</a> that there has been a consistent change in thermal comfort – the human body’s experience of the outdoor thermal environment – from the 1970s to today. Simply put, southern Africans are experiencing heat stress more often than in 1979.</p>
<p>Given that global temperatures are <a href="https://www.ipcc.ch/report/ar6/wg2/about/frequently-asked-questions/keyfaq3/">set to rise</a> in the coming years and decades, these findings are worrying. Warmer temperatures will mean that regions that were classified as having “favourable” thermal comfort will more regularly be classified as regions of “thermal stress”. Heatwaves have been projected to occur more frequently, and to be more intense.</p>
<h2>Measuring thermal comfort (or stress)</h2>
<p>Over the past two decades, scientists from across the world have developed the <a href="https://utci.lobelia.earth/what-is-utci">Universal Thermal Climate Index</a>. It has advanced our ability to model human thermal comfort levels, ranging from cold stress to heat stress. Earlier thermal comfort indices typically only modelled heat stress because they mainly measured the combined effects of humidity and temperature to calculate an equivalent temperature. </p>
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<img alt="" src="https://images.theconversation.com/files/506300/original/file-20230125-16-cpv882.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506300/original/file-20230125-16-cpv882.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=358&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506300/original/file-20230125-16-cpv882.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=358&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506300/original/file-20230125-16-cpv882.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=358&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506300/original/file-20230125-16-cpv882.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=450&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506300/original/file-20230125-16-cpv882.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=450&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506300/original/file-20230125-16-cpv882.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=450&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Temperature extremes can put people’s health at risk. Authors supplied.</span>
</figcaption>
</figure>
<p>This equivalent temperature would essentially measure how we feel in relation to the surrounding environment. For example, at 5pm on 23 January, Johannesburg’s outdoor air temperature was 29˚C; relative humidity was 30%; the sky was clear and there was a gentle breeze of 16km/h. </p>
<p>For someone outside, the equivalent temperature would have been slightly higher than the outdoor temperature (<a href="https://utci.lobelia.earth/images/what-is-utci/global-diff.png">possibly as high as 32˚C</a>), largely due to the effect of relative humidity and limited wind chill.</p>
<p>The Universal Thermal Climate Index considers a wider range of factors that influence thermal comfort than its predecessors. In addition to air temperature, relative humidity and wind speed, it also includes radiant heat, a measure of how hot we feel when standing in the sun rather than in the shade. </p>
<p>The index is built for humans navigating the real world: it includes a clothing model and an exertion model. </p>
<p>During the current southern African heatwave, for instance, the model assumes that nobody is dressed in a fuzzy jersey. In winter, it assumes nobody in countries like Namibia, Botswana, Zimbabwe, Mozambique, Eswatini, Lesotho and South Africa is wearing shorts and a T-shirt.</p>
<p>Ultimately, the inclusion of all these factors means that the Universal Thermal Climate Index is a more accurate and realistic indicator of the level of thermal comfort (or discomfort) perceived by the human body.</p>
<h2>Southern African application</h2>
<p>To apply the Universal Thermal Climate Index to southern Africa, we drew data from the <a href="https://cds.climate.copernicus.eu/cdsapp#!/dataset/derived-utci-historical?tab=overview">ERA5-HEAT</a> data collection, which provides an hourly dataset, of the equivalent temperature derived from the index, for 1940 to present; it is produced by the European Centre for Medium-Range Weather Forecasts.</p>
<p>We zoomed into the time period 1979-2021 and considered thermal comfort at annual, seasonal and monthly scales. Over these scales, we calculated the average climatology, and investigated changes and year-to-year variability patterns in day-time, night-time and daily average equivalent temperatures across southern Africa.</p>
<p>We found that heat stress occurs most widely during the summer months (December to March); cold stress occurs mainly during the winter months (June to August). Heat stress was, as one would expect, most common during the day and cold stress more common at night.</p>
<p>Drilling further into the data, we discovered that, from September to March, more than 85% of the subcontinent experiences day-time heat stress. Over parts of the Northern Cape in South Africa, Namibia, Botswana, Zimbabwe and Mozambique, day-time heat stress can reach very strong, and potentially dangerous, heat stress levels during these months. </p>
<p>From May to August, our results showed that more than 80% of southern Africa experiences night-time cold stress, and over much of South Africa night-time cold stress can reach moderate cold stress. In short, it’s unusual for people in the region to feel extremely cold and fairly common in certain months to feel extremely hot, especially outside.</p>
<h2>Going forward: why it’s bad news</h2>
<p>Everyone in southern Africa is at risk of heat stress. But children, the elderly, and those with underlying comorbidities are more vulnerable. </p>
<p>Those working outdoors, like farm and construction workers, are especially vulnerable because there’s little that can be done to adapt to and cope with heat stress while working outdoors during the day-time. <a href="https://www.timeslive.co.za/news/south-africa/2023-01-22-heat-stroke-deaths-department-suggests-working-early-late-hours/">Adjusting work hours</a> to avoid peak heat hours is one measure that could be applied.</p>
<p>There are also some coping mechanisms you could apply in your daily life. Limit your exposure to the sun by moving to shade or indoors to a well-ventilated or air-conditioned room. Keep hydrated (with water), avoid strenuous activities (like sports or excessive manual labour), wear lightweight protective clothing, a hat and sunblock, and, if you feel ill, seek medical attention.</p><img src="https://counter.theconversation.com/content/198455/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sarah Roffe works for the Agricultural Research Council. She receives funding from the National Research Foundation, South Africa. </span></em></p><p class="fine-print"><em><span>Jennifer Fitchett receives funding from the National Research Foundation</span></em></p><p class="fine-print"><em><span>Adriaan Van Der Walt does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Simply put, southern Africans are experiencing heat stress more often than in 1979.Sarah Roffe, Researcher, Agricultural Research CouncilAdriaan Van Der Walt, Senior Lecturer of Physical Geography and GIS, University of the Free StateJennifer Fitchett, Professor of Physical Geography, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1972012023-01-09T13:26:46Z2023-01-09T13:26:46ZThe South African government has been buying farmland for black farmers. It’s not gone well<figure><img src="https://images.theconversation.com/files/503265/original/file-20230105-1865-xupra0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Acquired land was used mostly for raising livestock rather than growing fruit, vegetables or field crops.</span> <span class="attribution"><span class="source">Peter Titmuss/Education Images/Universal Images Group via Getty Images</span></span></figcaption></figure><p>When the African National Congress came to power in South Africa in 1994, <a href="https://www.anc1912.org.za/policy-documents-1994-agricultural-policy/">an expressed priority was land reform</a>. This was to address the fact that black farmers had been excluded from the agricultural economy for most of the 20th century. The aim of land reform was to provide agricultural land to disadvantaged people, raising their productivity, income and employment. </p>
<p>A plethora of policy initiatives were launched. The target was to distribute 30% of agricultural land to black farmers. In 2006 the <a href="https://www.gov.za/sites/default/files/gcis_document/201409/impllandacquisition0.pdf">Proactive Land Acquisition Strategy</a> (PLAS) was adopted. This replaced the land redistribution programmes implemented between 1996 and 2006. The acquisition programme involved the government buying farmland previously owned by white farmers and redistributing it to black farmers. </p>
<p>But, overall, it’s become clear that the new approach to redistributing farmland has been mostly ineffective. Failure can be attributed to limited implementation, poor institutional capacity and corruption.</p>
<p>A <a href="https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.arc.agric.za%2FPages%2FBiometry.aspx&data=05%7C01%7C%7C1584a1faa2094b38624508dae1a4a59d%7Ca6fa3b030a3c42588433a120dffcd348%7C0%7C0%7C638070394852634326%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=vlFhP%2FWhEaeVcuDfIOPXoFZembkylR7THuz5kDcNUPo%3D&reserved=0">research report</a> first released in 2019 shed fresh light on how the most recent strategy has unfolded. Compiled by the Agricultural Research Council (ARC) for the Department of Rural Development and Land Reform, it provided a sober look at what happens when government bureaucrats get involved in land reform and farming decisions. </p>
<p>The main findings were that the performance on most farms bought under the acquisition scheme had been disappointing. More than half the current beneficiaries were not reporting any substantial production. The same percentage were evaluated as having a low capacity to achieve commercial status. </p>
<p>We argue that the data collected and interviews with stakeholders clearly indicate the reasons for failure. They include poor beneficiary selection, inadequate support and infrastructure, and rampant crime. Post settlement support was found to be inadequate, and stakeholders appointed to support the new farmers were poorly monitored and not working in an integrated manner. Agricultural infrastructure, both off farm and on farm, needed attention.</p>
<p>Based on our decades of experience in studying land policy, we believe that there is scope for the successful integration of farms acquired under the scheme into profitable value chains. But for this to happen, existing constraints need to be addressed.</p>
<h2>The plan</h2>
<p>The land acquisition programme was approved “in principle” in July 2003. It was officially implemented in 2006.</p>
<p>Between 2003 and August 2022, the state acquired 2.9 million hectares of farmland previously owned by white farmers through the Pro-active Land Acquisition Strategy. Around R12 billion (US$706 million) has been spent on the acquisition of these farms over the last 16 years. This land is made up of 2,921 farms and is under 30-year leases to beneficiaries. </p>
<p>The state also owns an additional 3,172 farms. It is unclear when and how these were acquired. Our best guess is that they were bought in the earlier iterations of the land redistribution programme. </p>
<p>The strategy was a noble attempt at land reform. It had some clear objectives:</p>
<ul>
<li><p>acquire land of high agricultural potential</p></li>
<li><p>integrate black farmers into the commercial agricultural sector</p></li>
<li><p>improve beneficiary selection</p></li>
<li><p>improve land use planning</p></li>
<li><p>ensure optimal productive land use.</p></li>
</ul>
<p>To establish the commercial potential and status of the farms, the Department of Rural Development and Land asked the Agricultural Research Council to conduct an analysis of all the land purchased under the scheme. Its remit was to:</p>
<ul>
<li><p>determine the agricultural potential of the land</p></li>
<li><p>establish the performance of the new farmers</p></li>
<li><p>define criteria for beneficiary selection</p></li>
<li><p>define criteria for contracting support agencies</p></li>
<li><p>establish interventions to help the scheme achieve its objectives.</p></li>
</ul>
<h2>The findings</h2>
<p>Most farms acquired under the initiative had high potential. It’s therefore possible to dismiss the myth that the land acquired for land reform was of poor quality.</p>
<p>The assessment showed that land acquired through the programme was generally of good or fair quality, and 98% of farms had fair to good natural resources. </p>
<p>Most farms (59%) were large enough in size and had a natural resource base sufficient to support viable enterprises. Some (7%) were doing well, despite limitations, indicating that it is possible for the programme to achieve its objectives.</p>
<p>The report noted that roughly 60% of all the farms had the potential to achieve commercial levels of production. Another 23% had the potential to reach significant (medium scale) levels of production. </p>
<p>Roughly 10% of the land had the capacity to support only livelihood level production. </p>
<p>According to the data, all the farms under review collectively employed 12,129 part-time and 7,045 full-time workers. Each farm on average employed six full-time and four part-time workers. Based on the potential of these farms, a total of 60,050 workers should be employed, suggesting that the growth and employment targets of the programme have been missed by a mile.</p>
<p>The report also looked at whether the farms were operational and in commercial production.</p>
<p>It found that performance on most was disappointing. More than half the current beneficiaries were not reporting any substantial production, and more than half the beneficiaries were evaluated as having a low capacity to achieve commercial status.</p>
<p>The report also addressed signs of degradation.</p>
<p>Nearly half (47%) of the farms that had been acquired were found to have some degree of degradation, while 13% were seriously or severely degraded. This was based on an evaluation of the land through satellite imagery and the data collected for the farm, compared to the potential based on land capability maps. Of concern was the high number of commercially viable farms (42%) and medium-scale farms (53%) that showed signs of degradation such as erosion and overgrazing.</p>
<p>The question of whether farmers were engaged in optimal farm enterprise mix was also addressed. It appears that most tended to avoid high value commodities (fruit, vegetables and field crops) in favour of livestock. This could be attributed to lack of skills, water constraints, insufficient suitable infrastructure and moveable assets, or limited access to capital. Of concern is the significant number (350) of farms that produced no commodities.</p>
<h2>What next</h2>
<p>The analysis showed that access to capital was one of the most critical resource limitations. To access capital from a commercial bank, the land bank or any private financial services outlet, farmers require collateral. Where farmers have title deed, this is facilitated. Lease agreements are not deemed collateral.</p>
<p>This points to the need to transfer the farm title deeds to farmers who have proven their capability. This would enable them to access finance via the Land Bank under its <a href="https://www.gov.za/speeches/minister-didiza-launches-r32-billion-blended-finance-scheme-land-bank-assist-farmers%C2%A0-24">newly launched blended finance programme</a>.</p>
<p>Farms with better infrastructure – housing, fencing, water reticulation, fixed assets and equipment – performed better. This illustrates the importance of infrastructural investment. </p>
<p>For land reform success in the future, the importance of selecting beneficiaries based on the criteria of entrepreneurial aptitude, resilience and technical skills will also be vital. The criteria described in the Proactive Land Acquisition Strategy stated that beneficiaries should be evaluated. But this appears not to have happened in practice. </p>
<p>The <a href="https://www.moneyweb.co.za/news/south-africa/what-the-anc-decided-at-its-national-conference/">latest resolution</a> on land reform passed by the ANC argues for legislative instruments to manage the state acquisition of land. The failures set out above suggest that the state will always be a poor player in redistributing land as it will always hold onto it. </p>
<p>The point of identifying mistakes in policy is, surely, not to repeat them.</p><img src="https://counter.theconversation.com/content/197201/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aart-Jan Verschoor was part of the Agricultural Research Council team that conducted a study and wrote a report commissioned by the Department of Rural Development and Land Reform on the South African government's land acquisition programme .</span></em></p><p class="fine-print"><em><span>Colleta Gandidzanwa was part of the Agricultural Research Council team that conducted a study and wrote a report commissioned by the Department of Rural Development and Land Reform on the South African government's land acquisition programme .</span></em></p><p class="fine-print"><em><span>Johann Kirsten does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The government’s approach to redistributing farmland has been mostly ineffective. Failure can be attributed to limited implementation, poor institutional capacity and corruption.Johann Kirsten, Director of the Bureau for Economic Research, Stellenbosch UniversityAart-Jan Verschoor, Senior Manager - Agrimetrics, Agricultural Research CouncilColleta Gandidzanwa, Researcher, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1818112022-05-04T14:31:37Z2022-05-04T14:31:37ZRemoving alien plants can save water: we measured how much<figure><img src="https://images.theconversation.com/files/459804/original/file-20220426-24-y59x8s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Alien trees threaten biodiversity, increase the risk of wildfires and also guzzle water.</span> <span class="attribution"><span class="source">Photo courtesy Cape Winelands Biosphere Reserve</span></span></figcaption></figure><p>Humans’ relationship with nature <a href="https://livingplanet.panda.org/en-us/">is broken</a>. We’re <a href="https://ipbes.net/global-assessment">transforming the Earth so dramatically</a> that almost one million plant and animals species face extinction. Losing species unravels the tapestry of nature, changing how ecosystems function and, ultimately, damaging society too.</p>
<p>Nature brings huge benefits to people. Some are tangible. In South Africa alone, the value of these benefits to people is estimated at <a href="https://linkinghub.elsevier.com/retrieve/pii/S2212041617304771">R275 billion annually</a> (about 7% of the country’s gross domestic product). That value includes providing the country with crops, wood, water and fuel. There are other, less immediately tangible benefits, too: air purification, water regulation, water purification, recreation, tourism, and cultural and heritage value.</p>
<p>One of the things that contributes to ecosystem degradation in South Africa is invasion by alien plants. This is estimated to <a href="https://www.sanews.gov.za/south-africa/sa-sees-increase-alien-species">cost the nation R6.5 billion annually</a> in damages and the <a href="https://www.greeneconomycoalition.org/news-and-resources/working-for-water-in-south-africa#:%7E:text=Working%20for%20Water%20currently%20runs,works%20programme%20in%20the%20country">government spends over R400 million annually</a> clearing alien trees. Despite this investment, <a href="https://www.sanews.gov.za/south-africa/sa-sees-increase-alien-species">alien tree invasions continue to increase across the country</a>.</p>
<p>Alien trees <a href="https://theconversation.com/invasive-alien-plants-in-south-africa-pose-huge-risks-but-they-can-be-stopped-94186">threaten biodiversity</a>, increase the risk of more intense and frequent wildfires and also guzzle water. This is an important factor in water scarce regions, like South Africa, that experience droughts.</p>
<p>Alien trees are invading mountainous areas across South Africa. These are important water generating regions and the trees threaten water supplies in several cities, among them Cape Town and Gqeberha. Both have experienced <a href="https://www.dailymaverick.co.za/article/2022-01-19-parts-of-eastern-cape-emerge-from-drought-but-gqeberha-dam-levels-are-still-below-19/">water shortages</a> in recent years.</p>
<p>To find out just how much alien trees threaten water supply, we conducted a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0022169422003468">hydrological study</a>. The research set up the most fine-scale, detailed models possible to try and estimate how alien trees affect streamflow in four small mountains catchments above some of Cape Town’s major dams. This study also used satellite imagery to input accurate information on the types of alien trees and where they are.</p>
<h2>Key findings</h2>
<p>The models predicted that clearing catchment areas fully infested with mature invasive alien trees can increase streamflow by between 15.1% and 29.5%. Although the catchments modelled are currently not fully invaded, this presents a strong argument for preventing full invasion. </p>
<p>The study also found that streamflow gains from clearing alien trees from rivers were almost twice as high as clearing the alien trees from the surrounding land. That’s because alien trees in rivers have access to an almost endless water supply and so use more.</p>
<p>Another interesting finding was that clearing alien trees seemed to have a greater impact on the mid to low flows – in other words during the dry season when the river flow is low, rather than the high flows – during rainfall events in the wet season when the rivers are full. </p>
<p>This makes sense: during rainfall events there is so much water that the negative effects of alien vegetation become less evident. But it is important because it implies that clearing alien trees makes more water available in between rain events, and especially in the dry season. This is useful to improve water security during droughts.</p>
<p>The positive effect of clearing alien trees was also predicted to be higher in dry years compared to wet years. This suggests that clearing alien trees is a viable measure to ensure there will be more water when it is most needed.</p>
<p>It is useful to explain what the savings predicted by our models mean to Cape Town’s overall water supply – and to consumers. For instance, we found that clearing the current levels of invasion in the catchments above the Berg River Dam (currently 9% invaded) could increase streamflow by over 1%. This doesn’t sound like a lot, but it could mean an increase in mean annual volume of as much as 1.5 million m³, or 4.1 million litres per day. </p>
<p>According to the 1:50 year yield model for the Berg River Dam, this equates to a 0.2% increase in yield. Putting this into perspective with a quick first order calculation, from the City of Cape Town’s Water Strategy, we have a value of R9 per kilolitre for the operating costs of desalination. If we multiply this by the 0.2% increase in yield each year from clearing alien trees above the Berg River Dam, we get to an estimated annual equivalent value of that water of around R2 million. </p>
<p>However should the Berg River Dam catchment become fully invaded with alien trees, this would reduce the 1:50 year yield by 4.3%, costing us about R38 million each year if we had to source this water elsewhere.</p>
<h2>Reversing the damage</h2>
<p>Our findings are important for several reasons. First, they can be used to encourage society to redouble its work clearing alien vegetation. Second, they confirm that improved water security is possible for South African cities during their dry seasons or droughts.</p>
<p>It is critical that more work be done to halt and reverse the degradation of ecosystems. This is especially urgent in what the United Nations has dubbed the <a href="https://www.decadeonrestoration.org/">Decade on Ecosystem Restoration</a>. We all have a chance to undo some of the damage we have wrought – and, as our research shows, clearing alien trees must be part of these efforts. </p>
<p><em>Jason Hallowes contributed to this article. We thank Dr James Cullis for help with the yield calculations and cost estimations.</em></p><img src="https://counter.theconversation.com/content/181811/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alanna Rebelo receives funding from the South African Water Research Commission. This work was funded by the Danish Ministry of Foreign Affairs (DANIDA) as part of the SEBEI (Socio-Economic Benefits of Investing in Ecological Infrastructure) Project, grant no: 17-M07-KU. She serves on the boards of the Friends of Tokai Park, South African Wetland Society, South African Hydrological Society, and the International Society of Wetland Scientists: Africa Region. </span></em></p><p class="fine-print"><em><span>Karen Joan Esler receives funding from Water Research Commission. She is affiliated with the International Society for Ecological Restoration. </span></em></p><p class="fine-print"><em><span>Mark New receives funding from a number of national and international research funders, including the South African National Research Foundation, the International Development Research Centre, UK Research and Innovation, the AXA Research Fund and the BNP-Paribas Foundation.</span></em></p><p class="fine-print"><em><span>Petra Brigitte Holden receives funding from the AXA Research Fund, through the AXA Research Chair in African Climate Risk and the International Development Research Centre.</span></em></p>Clearing alien trees from mountain catchments is a more cost-effective approach to providing water than building and maintaining desalination plants.Alanna Rebelo, Senior Researcher, Agricultural Research CouncilKaren Joan Esler, Distinguished Professor of Conservation Ecology, Stellenbosch UniversityMark New, Director, African Climate and Development Initiative, University of Cape TownPetra Brigitte Holden, Researcher, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1774632022-03-14T13:52:57Z2022-03-14T13:52:57ZClearing alien trees can help reduce climate change impact on Cape Town’s water supply<figure><img src="https://images.theconversation.com/files/451357/original/file-20220310-15-1gmwm5x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Alien pine trees, which use substantially more water than the native vegetation of the Cape Mountains, reduce river flows to dams that supply the city's water.</span> <span class="attribution"><span class="source">Martin Kleynhans</span></span></figcaption></figure><p>Droughts in water scarce regions are being <a href="https://www.carbonbrief.org/mapped-how-climate-change-affects-extreme-weather-around-the-world">aggravated by human-driven climate change</a>. While rainfall reduction is the main driver, increased temperature and evaporation can also play a role. </p>
<p>Another influence on drought severity is the condition of the catchment area where rain falls and drains into rivers. Important factors here include the amount and type of vegetation covering the catchment and soil characteristics. </p>
<p>One way of offsetting the impacts of climate change on water resources is catchment restoration, which can involve revegetation, wetland restoration, gully rehabilitation, and alien tree clearing. This is one of several types of <a href="https://www.naturebasedsolutionsinitiative.org/what-are-nature-based-solutions/">nature-based solutions</a>, which focus on reducing climate change impacts through working with nature.</p>
<p>But it’s not easy to tell what difference restoration makes on the impacts of <a href="https://theconversation.com/climate-explained-how-much-of-climate-change-is-natural-how-much-is-man-made-123604">human-aggravated changes in climate</a> on water availability during droughts. </p>
<p>In a <a href="https://www.nature.com/articles/s43247-022-00379-9">recently published analysis</a>, we took a closer look at the role of climate change and catchment conditions during the 2015-2017 <a href="https://dayzero.org.za/">Cape Town “Day Zero” drought</a>. This drought led to one of the most serious water crises experienced by any city in the world in recent times. The drought arose from a prolonged shortage of rainfall and, consequently, river flows, which progressively depleted reservoir storage in the area. </p>
<p>We wanted to see whether clearing alien trees from mountain catchments where the city’s water comes from would have lessened the impacts of climate change on the drought. This is the first study that has looked at the potential for nature-based solutions to buffer society from extreme event impacts directly linked to human-driven changes in the climate. </p>
<p>We found that clearing alien trees before the drought hit could have reduced the impact of climate change on water supply during the “Day Zero” drought. But it could not have removed all of the human-driven climate change impact on water availability.</p>
<h2>Alien trees and water supply</h2>
<p>In South Africa, <a href="https://doi.org/10.1007/978-3-030-32394-3_19">invasive alien tree clearing</a> is a well-known form of catchment restoration. These trees have spread across many mountain catchments critical for water supply. Alien trees <a href="https://doi.org/10.1007/978-3-030-32394-3_15">use substantially more water</a> than native vegetation because they are taller, have greater leaf areas, and have deeper root systems. These characteristics increase the amount of water lost due to transpiration from the tree, compared to native plants, leaving less water for river flow and groundwater recharge. Impacts from alien trees on water are felt especially during drought periods when water is most needed. </p>
<figure class="align-center ">
<img alt="Aerial shot of the invasive alien pine trees that have grown on the Cape mountains." src="https://images.theconversation.com/files/450981/original/file-20220309-20-lnnd60.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450981/original/file-20220309-20-lnnd60.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450981/original/file-20220309-20-lnnd60.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450981/original/file-20220309-20-lnnd60.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450981/original/file-20220309-20-lnnd60.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450981/original/file-20220309-20-lnnd60.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450981/original/file-20220309-20-lnnd60.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Invasive alien pine trees choking out the native vegetation of the Cape Mountains.</span>
<span class="attribution"><span class="source">Cape Winelands Biosphere Reserve</span></span>
</figcaption>
</figure>
<p>This situation is not unique to South Africa. <a href="https://doi.org/10.1371/journal.pone.0183210">Studies across the globe</a> confirm a decrease in water yields in response to afforestation (planting trees). </p>
<h2>Human influence on the rainfall shortages and reduced river flows</h2>
<p>Between 2015 and 2017, a very rare drought event – <a href="https://doi.org/10.3390/w9110876">the worst since 1904</a> – pushed Cape Town into a <a href="https://dayzero.org.za/">water crisis</a>. Researchers have previously found that climate change made the reduction in rainfall that triggered the crisis <a href="https://theconversation.com/global-warming-has-already-raised-the-risk-of-more-severe-droughts-in-cape-town-107625">three</a> to <a href="https://doi.org/10.1073/pnas.2009144117">six</a> times more likely. </p>
<p>The focus of these studies was on the rainfall shortage. But Cape Town’s water is dependent on river flows from distant mountainous catchments. Water flowing from these catchments is <a href="https://www.nature.org/content/dam/tnc/nature/en/documents/GCTWF-Business-Case-April-2019.pdf">captured and stored in six large dams</a>. During the drought, dam levels dropped to <a href="https://resource.capetown.gov.za/documentcentre/Documents/City%20research%20reports%20and%20review/Water%20Outlook%202018_Rev%2030_31%20December%202018.pdf">less than 20% of their capacity</a>.</p>
<p>Our <a href="https://rdcu.be/cIA8T">analysis</a> aimed to see whether clearing alien trees from these mountain catchments would have lessened the impacts of lower rainfall from climate change on river flows. </p>
<p>Using climate models and a hydrological model we simulated worlds with and without human-driven climate change and with and without catchment restoration and maintenance. We did this for two mountain catchments typical of those that supply the <a href="https://www.nature.org/content/dam/tnc/nature/en/documents/GCTWF-Business-Case-April-2019.pdf">Western Cape Water Supply System</a> which feeds Cape Town’s water delivery. </p>
<p>Our results suggest that climate change reduced river flows during the drought by 12-29% relative to a world with no human influence on the climate. This was larger than the 7-15% reduction in rainfall falling on these catchments that we could attribute to climate change. So the catchments amplified the climate change impact as water moved from rainfall to river flows.</p>
<p>Similarly to <a href="https://doi.org/10.1088/1748-9326/aae9f9">previous work</a>, we found some, but not a very large, influence of climate change on evaporation. </p>
<p>Our analysis showed that clearing alien trees before the drought hit could have reduced the impact of climate change on river flow during the drought. For example, clearing catchments with moderate invasions (40% coverage of alien trees) could have ameliorated river flow reductions attributed to climate change by 3-16%. Preventing the spread of alien trees to fully cover the catchments avoided 10-27% additional reductions in stream flow due to climate change. </p>
<h2>Going forward</h2>
<p>An important insight from our analysis is that fully clearing the catchments could not have completely offset the climate change impact. </p>
<p>So, while catchment restoration can make a difference for managing changing drought risk, it is not the complete solution for addressing climate change impacts on water resources, even at current levels of climate change. Catchment restoration needs to be combined with other adaptation options in water scarce regions facing a warmer and drier world. </p>
<p>Also, in many cases, climate change is not the only driver of water scarcity. Poor management, services, and infrastructure can easily override the benefits that nature-based solutions could offer. </p>
<p>While our results suggest nature-based solutions can be important, it is critical to realise that nature-based solutions should be context specific. An understanding of the local conditions is important in the design of any response.</p><img src="https://counter.theconversation.com/content/177463/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Petra Holden receives funding from the AXA Research Fund, through the AXA Research Chair in African Climate Risk, the Danish Ministry of Foreign Affairs (MFA) - grant number 17-M07-KU, the BNP Paribas Foundation Climate Initiative, and the International Development Research Centre. </span></em></p><p class="fine-print"><em><span>Alanna Rebelo receives funding from the South African Water Research Commission and the Danish Ministry of Foreign Affairs (MFA) - grant number 17-M07-KU.</span></em></p><p class="fine-print"><em><span>Joyce Kimutai receives funding from AXA Research Chair in African Climate Risk.</span></em></p><p class="fine-print"><em><span>Kamoru Abiodun Lawal receives funding from the South African Water Research Commission (WRC), AXA Research Fund, BNP-Paribas Foundation Climate Initiative, the GCRF African-SWIFT and the the European Union funded six-year Intra-ACP (African, Caribbean, Pacific Group of States) Climate Services and Related Applications (ClimSA) project. </span></em></p><p class="fine-print"><em><span>Mark New receives funding from a number of national and international research funders, including the South African National Research Foundation, the International Development Research Centre, UK Research and Innovation, the AXA Research Fund and the BNP-Paribas Foundation.</span></em></p><p class="fine-print"><em><span>Piotr Wolski receives funding from a number of national and international funders including RSA Department of Water and Sanitation, UNDP, UNEP, World Bank, NIH, SADC and EU. </span></em></p><p class="fine-print"><em><span>Romaric C. Odoulami receives funding from the AXA Research Fund, the Solar Radiation Management Governance Initiative (SRMGI), the DAAD ClimapAfrica, the Carnegie Developing Emerging Academic Leaders (DEAL) programme, and the BNP-Paribas Foundation Climate Initiative.</span></em></p><p class="fine-print"><em><span>Tiro Nkemelang receives funding from AXA Research Chair in African Climate Risk. </span></em></p>Clearing alien trees before the drought hit could have reduced the impact of climate change on water supply during the ‘Day Zero’ drought.Petra Brigitte Holden, Researcher, University of Cape TownAlanna Rebelo, Senior Researcher, Agricultural Research CouncilJoyce Kimutai, Climate Scientist, University of Cape TownKamoru Abiodun Lawal, Postdoctoral Research Fellow in Atmospheric Science, University of Cape TownMark New, Director, African Climate and Development Initiative, University of Cape TownPiotr Wolski, Senior Researcher in Hydro-Climatology, University of Cape TownRomaric C. Odoulami, Postdoctoral Research Fellow, University of Cape TownTiro Nkemelang, PhD student in African Climate Risk, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/866402017-11-12T09:45:01Z2017-11-12T09:45:01ZHow barcoding is helping South Africa track its precious pollinators<figure><img src="https://images.theconversation.com/files/193921/original/file-20171109-27138-h0we60.jpg?ixlib=rb-1.1.0&rect=13%2C327%2C2141%2C1345&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The well-being of pollinators like bees have a direct impact on our lives.</span> <span class="attribution"><span class="source">Vida van der Walt</span></span></figcaption></figure><p>Pollinators are the unsung heroes of food production. Almost one third of the food eaten comes from animal <a href="http://www.sajs.co.za/pollination-impact-role-players-interactions-and-study-%E2%80%93-south-african-perspective/annemarie-gous-sandi-willows-munro-connal-eardley-zacharias-h-dirk-swanevelder">pollination</a>. Animal pollinated foods also contain nutrients and minerals essential to human diets and they maintain natural areas by pollinating wild plants.</p>
<p>But understanding the relationship between plants and pollinators isn’t straightforward. Nevertheless, it matters because some indigenous pollinators are under threat. This is particularly challenging in South Africa which has a rich collection of indigenous pollinators. The list includes bees, predacious wasps, pollen wasps, beetles, moths and birds. This huge diversity makes it even more difficult to study plant interactions with pollinators purely through observation. </p>
<p>In the last couple of years, DNA-based techniques like <a href="https://www.ebi.ac.uk/training/online/course/ebi-next-generation-sequencing-practical-course/what-you-will-learn/what-next-generation-dna-">next generation sequencing</a> have been increasingly used to identify pollen on pollinators and their products, like honey. <a href="http://ibol.org/">The technology</a> reads the DNA from a mixed pollen sample and then compares the DNA to a reference database to obtain identifications. The short, specific DNA fragments targeted from the pollen sample are used as “barcodes” to identify the plant species from which it originated. Using a standard set of genes, combined with next generation sequencing, to identify plant species from their pollen is referred to as metabarcoding.</p>
<p>Pollen metabarcoding has led to huge strides in understanding the relationship between pollinators and plants. And there’s an <a href="http://acdb.co.za/acdb-dna-bank/">ongoing project</a> to barcode the plants of southern Africa, using genes in the chloroplasts of plants. This is undoubtedly good news for the metabarcoding of mixed pollen samples to study plant-pollen interactions. </p>
<p><a href="http://www.sajs.co.za/pollination-impact-role-players-interactions-and-study-%E2%80%93-south-african-perspective/annemarie-gous-sandi-willows-munro-connal-eardley-zacharias-h-dirk-swanevelder">In our recent review</a>, we discussed the field of plant-pollinator interactions and the impact and study of these relationships, focusing on South Africa. It highlights the advances made by South African scientists using cutting edge molecular technologies like pollen metabarcoding. </p>
<p>This work has the potential to shed new light on the complexity of pollination in South Africa’s ecosystems – in both the natural as well as agricultural ecosystems. </p>
<h2>Why it’s complicated</h2>
<p>A generalist, nonselective pollinator can pollinate multiple plant species, or several pollinators could pollinate a single plant. </p>
<p>Exclusive relationships also exist. This happens when specialised pollinators and plants have a close mutualistic relationship. In some cases, they develop compatible morphological features like, for example, the oil collecting bees (genus <em>Rediviva</em>) and <em>Diascia</em> flowers. </p>
<p>Pollinators seen on a flower may be visiting them for rewards other than pollen. They could, for example, be hunting for nectar. And it’s possible that they may not be involved in the successful pollination of the flower they were visiting. The pollen found on these pollinators could have come from a different plant species altogether. So, observing pollinators on flowers could be misleading in trying to understand pollination networks. </p>
<p>Traditionally, plant-pollinator interactions were investigated through field observations, microscopic pollen identification – or palynology – and cage studies. The process was slow and required a lot of expertise to correctly identify plants from their pollen. </p>
<h2>How do DNA-based techniques work?</h2>
<p>Increasingly DNA-based techniques – like next generation sequencing – are being used to identify pollen on pollinators and their products. </p>
<p><a href="http://ibol.org/">The technology</a> reads the DNA amplified from a mixed pollen sample, and then compares the DNA to a reference database for identification. Mixed pollen samples can be identified by genes contained in pollen nuclei or chloroplasts. Using a combination of these genes in the identification of mixed pollen samples provides <a href="https://doi.org/10.3732/apps.1500043">more accurate results</a> than studying only a single gene.</p>
<p>The sequence reference database used to compare pollen DNA sequences needs to be <a href="https://doi.org/10.1139/gen-2015-0200">suitably comprehensive</a> to get accurate identifications. The project to barcode plants in southern Africa is making significant progress. This means that the sequence database for the country’s diverse plants are becoming more complete for the genes used in pollen metabarcoding. In turn, this means that more accurate identifications can be made from pollen collected from pollinators. </p>
<p>The well-being of pollinators has a direct impact on our lives – from the food we eat, to the clothes we wear and even the natural environments we relax in. On top of this, the interactions between pollinators and plants ensure the long term sustainability of agricultural and native environments. </p>
<p>Understanding these interactions and how they change over time will help us to identify what’s threatening plant and pollinator communities, both of which are key to long term food and ecosystem sustainability.</p><img src="https://counter.theconversation.com/content/86640/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dirk Swanevelder receives funding from the Agricultural Research Council. </span></em></p><p class="fine-print"><em><span>Annemarie Gous was also funded by the Department of Science and Technology and National Research Foundation Professional Development Programme (grant 99781), the Biotechnology Platform at the Agricultural Research Council (ARC), as well as the Professional Development Programme of the ARC</span></em></p><p class="fine-print"><em><span>Connal D. Eardley, receives funding from the NRF, ARC, DST & Belgian Directorate–General for Development Cooperation, partim GTI,</span></em></p><p class="fine-print"><em><span>Sandi Willows-Munro receives funding from National Research Foundation. </span></em></p>Pollination in South Africa’s ecosystems is extremely complex. However new advances such as pollen metabarcoding help us understand interactions between pollinators and pollen.Dirk Swanevelder, Senior Researcher, ARC Biotechnology Platform, Agricultural Research CouncilAnnemarie Gous, PhD in Conservation Genetics, Agricultural Research CouncilConnal D. Eardley,, Specialist Scientist Plant Protection Research Institute Agricultural Research Council, South Africa, Agricultural Research CouncilSandi Willows-Munro, Researcher and Lecturer Genetics, University of KwaZulu-NatalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/651712016-11-20T12:10:53Z2016-11-20T12:10:53ZFeeding pigs in Africa is expensive. Changing their diets is the answer<figure><img src="https://images.theconversation.com/files/146054/original/image-20161115-31132-zhdeme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">One of the major reasons for the lack of growth in pig production is high pig feed costs.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Pork is one of the cheaper protein sources that can contribute towards food security in Africa. Pigs are omnivores, and as such are ideally suited to convert non human edible feed stuffs into high quality food animal protein. Pork consumption has grown tremendously over the years across the world, but production has not responded sufficiently to meet demand. It has been projected that almost 45% of additional pork consumption will <a href="http://www.oecd-ilibrary.org/docserver/download/5116021e.pdf?expires=1479236491&id=id&accname=guest&checksum=8F7EB07EB62E3D55E5C66071F3B484C3">be imported</a>.</p>
<p>Pig numbers in Africa increased steadily from 33.8 million in 2013 to 34.5 million <a href="http://faostat3.fao.org/browse/Q/QA/E">in 2014</a>. But this rate will clearly not be sufficient to meet the demands of a growing population on the continent which currently stands at about 950 million people. Between 2013 and 2015 pork made up 12% of all meat consumed in sub Saharan Africa. This is <a href="http://www.keepeek.com/Digital-Asset-Management/oecd/agriculture-and-food/oecd-fao-agricultural-outlook-2016-2025/livestock-mix-across-the-sub-saharan-african-region_agr_outlook-2016-graph23-en#.WCr26tJ97IU#page1">much lower</a> than poultry (36%), beef (33%) and sheep (19%). Cultural and religious concerns have largely limited pork consumption in many countries but urbanisation is changing this. </p>
<p>One of the major reasons for the lack of growth in pig production is high pig feed costs. Pig producers normally use a narrow range of ingredients which include maize, wheat, sorghum, soybean oilcake and sunflower oilcake among others in formulating pig diets. They are often forced to compete with humans and poultry for feed resources, making the cost of producing pigs prohibitive. Recurring droughts due to global warming are exacerbating the situation. </p>
<p>The other problem is that some high fibre diets aren’t the best for pig production. Pigs don’t grow as fast because some fibre – like wheat bran – reduces feed intake and dilutes the available protein, energy, minerals and vitamins necessary for growth. But not all fibres are the same: some are better than others.</p>
<p>To solve both the cost and the fibre issues the pig industry must find ways to effectively make use of readily available fibrous feeds from industries that <a href="https://www.cambridge.org/core/journals/animal/article/influence-of-dietary-fibre-level-and-pelleting-on-the-digestibility-of-energy-and-nutrients-in-growing-pigs-and-adult-sows/2CABC3780687019F6D4B5AD97D6099AF">process agricultural products</a>. This would result in cheaper production of pigs and a more food secure continent.</p>
<h2>What fibres work and which ones don’t</h2>
<p>The major challenge in using fibrous feeds in pig diets is that pigs’ digestive enzymes can’t break down certain fibre components to a state that can be utilised by the animals. In addition, high fibre diets increase the rate of feed passage in the pig gut and trap nutrients in the fibre matrix making them unavailable <a href="http://www.thepigsite.com/articles/4910/high-fibre-swine-diets/">for digestion</a>. Fibre also imputes bulkiness to diets which limits the quantity of feed the pig can consume. </p>
<p>But fibres shouldn’t be grouped under a blanket term. Not all are a bad food choice for pigs. Fibres differ in their physical and chemical properties which affects the solubility of the fibre. Soluble and insoluble components of fibre differ in how they influence the number, range and types of microorganisms in the gut, fermentation patterns and absorption of nutrients.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/146206/original/image-20161116-13503-opyg4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/146206/original/image-20161116-13503-opyg4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/146206/original/image-20161116-13503-opyg4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/146206/original/image-20161116-13503-opyg4a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/146206/original/image-20161116-13503-opyg4a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/146206/original/image-20161116-13503-opyg4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/146206/original/image-20161116-13503-opyg4a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/146206/original/image-20161116-13503-opyg4a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pork has the
ability to help Africa’s food security.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>A better understanding of these dynamics will lead to sustainable use of fibrous ingredients in pig diets. Sugar beet pulp, for example, is highly soluble and can be used at relatively high levels. Meanwhile wheat bran, which is highly insoluble, may be used in moderate quantities because of its laxative effects.</p>
<p>Pigs can also extract up to 25% of the energy they need from fibre fermentation products. This would mean that grains in their <a href="http://ajas.info/journal/view.php?doi=10.5713/ajas.15.0053">diets</a> could be reduced. Besides the economic benefits from using cheaper fibrous byproducts in pig feed, there are also environmental gains. Most of these byproducts are often dumped inappropriately leading to water and air pollution.</p>
<h2>The impact of fibrous diets</h2>
<p><a href="https://jasbsci.biomedcentral.com/articles/10.1186/2049-1891-4-11">Most research</a> has focused on the impact of the fibrous diets on growth performance of the pigs. But there is a need to quantify the beneficial effects of high fibre diets on intestinal health and welfare.</p>
<p>Dietary fibre improves pig health by promoting the growth of lactic acid bacteria, the “good bacteria”. These suppress the multiplication of disease causing bacteria like <em>E. coli</em> and <em>Salmonella</em> by lowering the pH in the <a href="https://www.ncbi.nlm.nih.gov/pubmed/26500769">pig intestines</a>. This contributes to food safety because people can get <em>E. coli</em> and <em>Salmonella</em> from eating pig meat that’s been contaminated in this way, poisoning them.</p>
<p>Dietary fibre also reduces stress and behavioural <a href="http://www.appliedanimalbehaviour.com/article/S0168-1591(03)00305-8/references">problems in pigs</a>. This is especially important given that intensive farming is increasingly being used to produce pigs. This has been shown to be quite stressful with detrimental effects on production. For example, <a href="https://jasbsci.biomedcentral.com/articles/10.1186/2049-1891-4-11">sows appear to be less stressed</a> and to move around less if they are physically and nutritionally satisfied.</p>
<p>Pigs can also use diets with high fibre better if enzymes that break down fibre are added to their diets. Another option is to allow the fibrous sources of pig feed to ferment under anaerobic conditions (without oxygen) – a process called ensiling. Ensiling breaks down fibre and also improves the <a href="https://www.researchgate.net/publication/270506924_Kanengoni_A_T_Chimonyo_M_Ndimba_B_K_and_Dzama_K_2015_Feed_preferencenutrient_digestibility_and_colon_volatile_fatty_acid_production_in_growing_SouthAfrican_Windsnyer-type_indigenous_pigs_and_LargeWhit">taste of the feed</a>.</p>
<p>Other approaches to break down the fibre matrix structure include fermentation and the use of fibre degrading enzymes or strong acids. These break down the fibre components to their basic constituents which is better for pigs. But the use of strong acids isn’t the best option because of safety, environmental and <a href="http://www.sciencedirect.com/science/article/pii/S036012851200007X">economic concerns</a>. </p>
<p>There are many benefits to including fibrous ingredients in pig diets, but they are not accounted for in normal diet formulations. The evidence points to the fact that high fibre diets are good for pigs and should be used more than is currently the case.</p><img src="https://counter.theconversation.com/content/65171/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arnold Kanengoni does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>High feed costs is limiting pig production in Africa. There are alternatives. The industry must find ways to use available feeds from industries that process agricultural productsArnold Kanengoni, Manager: Veterinary Services and Research, Agricultural Research CouncilLicensed as Creative Commons – attribution, no derivatives.