tag:theconversation.com,2011:/us/topics/table-mountain-31781/articlesTable mountain – The Conversation2022-05-03T13:50:32Ztag:theconversation.com,2011:article/1821692022-05-03T13:50:32Z2022-05-03T13:50:32ZHow vulnerable is the University of Cape Town to destructive wildfires?<figure><img src="https://images.theconversation.com/files/460512/original/file-20220429-20-ut9yfa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A water chopper hovers over University of Cape Town on April 18, 2021 as a wildfire spread across the mountain.</span> <span class="attribution"><span class="source">Brenton Geach/Gallo Images via Getty Images</span></span></figcaption></figure><p>Just over a year ago, a wildfire caused <a href="https://www.news.uct.ac.za/news/photoessays/-article/2021-04-20-in-pictures-runaway-fire-destroys-some-of-ucts-historical-buildings">considerable damage</a> to the University of Cape Town and surroundings. Irreplaceable <a href="https://theconversation.com/significant-archives-are-under-threat-in-cape-towns-fire-why-they-matter-so-much-159299">African collections</a> were destroyed. The <a href="https://mostertsmill.co.za/">last active windmill in Africa</a> was severely damaged. Many were surprised by the fire and the <a href="https://www.news.uct.ac.za/article/-2021-04-23-sad-moment-as-treasured-jagger-reading-room-remembered">widespread damage</a> it caused. </p>
<p>Two previous autumn fires in <a href="https://www.iol.co.za/news/south-africa/fireman-injured-battling-table-mountain-blaze-56396">March 2001</a> and <a href="https://web.archive.org/web/20090320233452/http://www.iol.co.za/index.php?set_id=1&click_id=13&art_id=nw20090318045517793C643498">March 2009</a> approached the university campus. The 2009 fire even scorched some trees on the <a href="https://www.news.uct.ac.za/article/-2009-03-30-devils-peak-blaze-skirts-upper-campus">campus boundary</a>. </p>
<p>What has been learnt about the risk of a repeat event?</p>
<p>Fire risk is the consequence of <a href="https://theconversation.com/the-table-mountain-fire-what-we-can-learn-from-the-main-drivers-of-wildfires-159477">interrelated factors</a> and is complex. As part of my PhD research I have examined the relationship between <a href="https://ascmo.copernicus.org/articles/8/31/2022/">wind and rainfall variability</a> and specifically to the <a href="https://ascmo.copernicus.org/articles/8/63/2022/">2015-2017 drought in Cape Town</a>.</p>
<p>In this article I look at some of these factors in relation to the 2021 fire and their potential influence on future events.</p>
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Read more:
<a href="https://theconversation.com/the-table-mountain-fire-what-we-can-learn-from-the-main-drivers-of-wildfires-159477">The Table Mountain fire: what we can learn from the main drivers of wildfires</a>
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<p>Hot and windy weather during ever drier and warmer autumns after the summer dry season represent a particular risk. Fires around the university are <a href="https://www.news.uct.ac.za/article/-2021-06-23-reflecting-on-the-devastating-uct-fire">necessary and inevitable</a>, but dense, flammable, often invasive scrub on the campus perimeter and some of the <a href="https://www.sanparks.org/assets/docs/parks_table_mountain/tmnp-fire-investigation-report.pdf">trees around buildings enhance the risk</a>. </p>
<p>But there’s much we don’t know and urgently need to <a href="https://www.news.uct.ac.za/article/-2021-06-23-reflecting-on-the-devastating-uct-fire">research further</a>. </p>
<h2>The event</h2>
<p>SANParks, the body responsible for managing South Africa’s national parks, commissioned <a href="https://www.sanparks.org/assets/docs/parks_table_mountain/tmnp-fire-investigation-report.pdf">a study</a> investigating the cause of – and response to – the fire. The study found that it was deliberately started before 9am on 18 April 2021. The suspects were driving on a freeway along Devil’s Peak, the spectacular backdrop to the university jutting out from Table Mountain. </p>
<p>Initially the fire spread slowly in calm conditions. But from 10am conditions suddenly deteriorated as dry, gusty north-westerly winds arrived. The fire intensified and destroyed buildings in the zone where natural areas transition to built up spaces – what’s known as <a href="https://www.news.uct.ac.za/article/-2021-06-23-reflecting-on-the-devastating-uct-fire">the Wildland Urban Interface</a>.</p>
<h2>Fire causes</h2>
<p>A recent paper introduces the concept of <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.14861">ignition catchments</a> – roughly, all the places a fire could start from to reach you. The university campus’s catchment is much smaller than it was in <a href="https://www.researchgate.net/publication/270684981_Burning_Table_Mountain_an_environmental_history_of_fire_on_the_Cape_Peninsula">pre-colonial times when fires could freely cross the Cape Flats</a>. </p>
<p>During the <a href="https://researchspace.csir.co.za/dspace/bitstream/handle/10204/4451/van%20Wilgen_2010.pdf?sequence=1">fire season</a> (roughly December to April), winds mostly come from <a href="https://ascmo.copernicus.org/articles/8/31/2022/">the south or south-east</a>. South-east of the university lie suburbs which are unlikely to sustain large fires. To the south, the indigenous Afrotemperate Forest of Newlands would likely act as a <a href="https://www.iol.co.za/news/south-africa/fireman-injured-battling-table-mountain-blaze-56396">“natural firebreak”</a>. </p>
<p>Only fires starting in the small grassy area between the forests and the university, invaded by flammable trees, pose a significant risk from the south.</p>
<p>Fires coming downhill from the west would tend to <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0245132">spread more slowly</a>. But under certain conditions, the risk of downhill spotting – fires lit by burning embers shot out ahead of the main fireline –<a href="https://www.sciencedirect.com/science/article/pii/S2212420918307623">may be greater</a>. </p>
<p>Spotting was responsible for the fire gutting buildings in the middle of campus. It crossed a <a href="https://www.timeslive.co.za/sunday-times/opinion-and-analysis/2021-05-09-the-fire-at-uct-not-just-the-usual-suspects/">four-lane highway</a> in multiple places, as fires were lit 350m ahead of <a href="https://www.sanparks.org/assets/docs/parks_table_mountain/tmnp-fire-investigation-report.pdf">the main firefront</a>. </p>
<p>North-westerly winds also pose a considerable fire weather risk for the university. In a <a href="https://ascmo.copernicus.org/articles/8/31/2022/">recent paper</a> we examined the relationship between wind direction and rainfall in the area. Usually north-westerly winds bring cool, moist and cloudy weather after travelling across the cold <a href="http://app01.saeon.ac.za/sadcofunstuff/MajorOceanCurrents.htm">Benguela Current</a> along southern Africa’s west coast. Sometimes in autumn, though, such as on the day of the fire, they are hot, dry and gusty. </p>
<p>The wind pattern around Table Mountain is <a href="https://core.ac.uk/download/pdf/20274056.pdf">extremely complex</a>. Nearby wind data are hard to obtain, but we do know that at the <a href="http://www.meteomanz.com/sy1?ty=hd&ind=68816&d1=18&m1=04&y1=2021&d2=18&m2=04&y2=2021&h1=12Z&h2=12Z&l=1">airport</a> and <a href="http://www.meteomanz.com/sy1?ty=hd&ind=68817&d1=18&m1=04&y1=2021&d2=18&m2=04&y2=2021&h1=12Z&h2=12Z&l=1">harbour</a>stations, north-westerly winds gusted to over 40km/h around 2pm.</p>
<p>This led to a very high <a href="https://twitter.com/TableMountainNP/status/1383781973353582600">predicted fire danger index</a>. Near the university, the South African Weather Service recorded maximum temperatures of 35.8°C. </p>
<p>Relative humidity is the other <a href="http://scholar.sun.ac.za/bitstream/handle/10019.1/113027/van%20Wilgen_FynbosEcolEvolConserv_2015.pdf?sequence=3&isAllowed=y">crucial meteorological determinant of fire behaviour</a>. At 11am it was just 10% <a href="http://www.meteomanz.com/sy1?ty=hd&ind=68819&l=1&d1=18&m1=04&y1=2021&d2=18&m2=04&y2=2021&h1=09Z&h2=09Z">in town</a>. This is drier than desert air usually is. Such low humidity is known to drive extreme fire behaviour.</p>
<h2>Hotter, drier autumns</h2>
<p>The three preceding weeks were also unseasonably hot and dry. A very slow-moving regional <a href="https://twitter.com/extremetemps/status/1381998574460932099">dome of heat</a> drove this pattern. During April 2021 Cape Town received <a href="https://www.weathersa.co.za/home/historicalrain">less than 25% of normal rainfall</a>.</p>
<p>A recent <a href="https://www.researchgate.net/publication/329486149_Mechanisms_behind_early_winter_rainfall_variability_in_the_southwestern_Cape_South_Africa">study</a> found a long-term pattern of autumn drying, predicted to get worse with climate change. Dry autumns were associated with a wave-4 pattern in the Southern Hemisphere (four pairs of highs and lows around the hemisphere). It is clearly visible in April 2021 <a href="https://climexp.knmi.nl/monthly_overview_world_weather/index.cgi?var=t2m_ecmwf_w&mon1=apr&year1=2021&anomalie=ja&kort=nee&expert=nee&type=kaartwereld">temperature</a> and <a href="https://climexp.knmi.nl/monthly_overview_world_weather/index.cgi?var=z500_ecmwf_sh&mon1=apr&year1=2021&anomalie=ja&kort=nee&expert=ja&type=kaartwereld&id=">pressure anomalies</a> (deviations from normal).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/460511/original/file-20220429-13-e8nbdd.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graph with blue squiggly lines showing different temperatures." src="https://images.theconversation.com/files/460511/original/file-20220429-13-e8nbdd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/460511/original/file-20220429-13-e8nbdd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/460511/original/file-20220429-13-e8nbdd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/460511/original/file-20220429-13-e8nbdd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/460511/original/file-20220429-13-e8nbdd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=536&fit=crop&dpr=1 754w, https://images.theconversation.com/files/460511/original/file-20220429-13-e8nbdd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=536&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/460511/original/file-20220429-13-e8nbdd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=536&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Average monthly temperature anomalies (deviations from the long-term average) for April from 1910-2021 from the Berkeley Earth daily maximum temperature dataset over the South-Western Cape (west of 19°E and south of 33°S)</span>
<span class="attribution"><span class="source">Author supplied</span></span>
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</figure>
<p>Long-term, continuous temperature data for individual locations in South Africa are very difficult to assemble. In gridded <a href="http://berkeleyearth.org/">Berkeley Earth</a> maximum temperature data for the area around Cape Town since 1910, the three warmest Aprils were 2014, 2017 and 2021. Other temperature <a href="http://climexp.knmi.nl/selectfield_obs2.cgi?id=6412952fc2d9242730e393cea7c0d7da">datasets</a> yield similar results. So do nearby <a href="http://www.meteomanz.com/sy3?cou=0&ind=68715&y1=2000&m1=01&y2=2021&m2=12&fm=04&so=102">station data</a> available <a href="http://www.meteomanz.com/sy3?cou=0&ind=68817&y1=2000&m1=01&y2=2021&m2=12&fm=04&so=102">since 2000</a>.</p>
<p>Given the findings of recent drought <a href="https://www.worldweatherattribution.org/the-role-of-climate-change-in-the-2015-2017-drought-in-the-western-cape-of-south-africa/">attribution</a> studies for the region, it is likely that the autumn warmth and dryness have become more common recently due to climate change. However, <a href="https://link.springer.com/article/10.1007/s10584-011-0030-z">many other variables</a> that are more difficult to analyse also influence plant susceptibility to fire.</p>
<h2>Fuels</h2>
<p>After the March 2009 fire the University of Cape Town removed some alien trees to reduce fuel loads. It has now removed most of the remaining pine and other alien tree stands along the north-western perimeter of Upper Campus. </p>
<p>Over the past two decades, SANParks has also made significant progress in <a href="https://www.jstor.org/stable/26269053?seq=1#metadata_info_tab_contents">clearing invasive tree stands</a>. This despite intense opposition, mostly from local recreational users who frequently support “forest” preservation with arguments based on ecological and climatic <a href="https://www.iol.co.za/capetimes/news/breaking-down-myth-planting-forests-could-help-drought-regions-15294218">misconceptions</a>.</p>
<p>However, at the time of the 2021 fire dense stands of flammable, mostly alien <a href="https://tokaipark.com/2021/04/devils-peak-fire/">shrubs and low trees</a> dominated some areas bordering <a href="https://www.sciencedirect.com/science/article/pii/S0254629914001732">the campus</a>, particularly in the north where the fire came from. Despite extensive clearing operations since the fire, a dense thicket of invasive alien shrubs and trees is emerging along both sides of the university perimeter. It will need to be monitored as a future fire risk.</p>
<p>The native fynbos and renosterveld vegetation are both <a href="https://www.tandfonline.com/doi/abs/10.2989/10220119.2021.1991473?src=recsys">fire-prone and fire-dependent</a>, whereas introduced tree and shrub species are also <a href="https://www.timeslive.co.za/news/south-africa/2021-04-24-born-to-burn-the-alien-trees-that-turned-cape-town-fire-into-a-disaster/">adapted to burning</a> and <a href="http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532009000500009">proliferating rapidly thereafter</a>.</p>
<p>Hence, rapid spread of fire near the University of Cape Town is an ever-present <a href="https://tokaipark.com/wp-content/uploads/2022/04/UCT-2012-%E2%80%93-UCT-Heritage-Park-Management-Framework.pdf">risk</a> once fuel loads are restored. </p>
<p><em>A longer version of the article can be found <a href="https://www.csag.uct.ac.za/2022/04/18/devils-peak-fire-18-19-april-2021-one-year-later/">here</a>.</em></p><img src="https://counter.theconversation.com/content/182169/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stefaan Conradie received funding from the South African National Research Foundation. </span></em></p>Fire spreading rapidly is always a risk at the University of Cape Town.Stefaan Conradie, PhD student, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1368902020-05-11T14:13:30Z2020-05-11T14:13:30ZWe found high UV doses at high-altitude hiking trails in Reunion and Cape Town<figure><img src="https://images.theconversation.com/files/332715/original/file-20200505-83725-1pq0shf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A couple taking in the view from Table Mountain, Cape Town.</span> <span class="attribution"><span class="source">Getty Images</span></span></figcaption></figure><p>Ultraviolet (UV) radiation from the sun is important for life on earth and especially for humans. </p>
<p>In <a href="http://www.scielo.org.mx/pdf/rmcp/v10n2/2448-6698-rmcp-10-02-416-en.pdf">animals</a> UV radiation is essential for biological functions like calcium metabolism. In <a href="https://books.google.com/books?id=Rq3SBAAAQBAJ&lpg=PA131&ots=BpvaX092Oa&dq=Caldwell%2C%20M.%20M.%20%3A%20Solar%20UV%20irradiation%20and%20the%20growth%20and%20development%20of%20higher%20plants%2CPhotophysiology%2C%206%2C%20131%E2%80%93177%2C%201971.&lr&hl=fr&pg=PA131#v=onepage&q&f=false">vegetation</a> it’s necessary for photosynthesis. And in humans, UV plays an <a href="https://www.mdpi.com/52688">important</a> role in synthesis of <a href="https://www.who.int/uv/resources/FAQ/uvhealtfac/en/index1.html">vitamin D</a>, which makes for strong bones, joints and muscles. </p>
<p>But too much UV radiation is also very dangerous for human health. Excessive exposure can cause skin ageing and sunburn and can induce skin cancer such as <a href="https://www.ncbi.nlm.nih.gov/books/NBK481848/">melanoma</a>, cataracts, ocular melanoma, and immunodeficiency. </p>
<p>The sun is the main natural source of <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-4632.2010.04474.x">ultraviolet radiation</a>. The risk for human health also depends on <a href="https://www.who.int/uv/publications/en/UVIGuide.pdf">UV intensity</a>. The UV level is affected by several atmospheric factors, such as ozone, aerosol, cloud cover or altitude. This is one reason why changes to the <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/91GL02786">ozone layer</a> as a result of global pollutant emissions make a difference to human health. The UV intensity is higher at <a href="https://www.who.int/uv/publications/en/UVIGuide.pdf">high altitudes</a> because there is less atmosphere to absorb it. Tropical regions also experience high UV exposure because the sun shines there a lot of the time.</p>
<p>We tested the <a href="https://www.mdpi.com/2073-4433/10/10/589">UV exposure</a> in high-altitude sites in Cape Town and Reunion Island. We assessed human exposure for hiking activities at two popular high-altitude hiking trails on the Maïdo–Grand Bénare (Reunion) and Table Mountain (Cape Town) with a handheld radiometer. We recorded extreme exposure doses. </p>
<p>These high exposure doses highlight the importance of raising public awareness on the risk related to excess UVR exposure at tourist sites, especially those at high altitude. Our findings suggest a need for strong public awareness campaigns among visitors to sites like these to prevent skin diseases and cancers that could result from overexposure to UV radiation.</p>
<h2>Our study</h2>
<p>We chose our testing sites – Table Mountain (altitude of 1,035 metres) in Cape Town and Maïdo-Grand Bénare (2,898 metres) on Reunion Island – because they are popular tourist destinations for outdoor activities for most of the year. Yet their high risk for UV is not necessarily well known. Tourists, hikers and employees of the local national parks may be exposed to high UV levels. Every year, <a href="https://www.tablemountain.net/annual_report_2019/">1,000,000 people</a> visit Table Mountain and <a href="http://www.ipreunion.com/photo-du-jour/reportage/2016/05/21/observatoire-regional-du-tourisme-le-tourisme-a-la-reunion-grimpe-de-1-pour-le-premier-trimestre-2016,44240.html">180,000 hike</a> on Réunion Island mountain.</p>
<p>Two markers were used to quantify the UV exposure. One was the UV index, <a href="https://www.who.int/uv/intersunprogramme/activities/uv_index/en/">defined</a> by the World Health Organisation (WHO) as a simple number for public awareness. UV index categories are low (1-2), moderate (3-5), high (6-7), very high (9-10), and extreme (11+). </p>
<p>The maximum UV index numbers recorded were 14 at Table Mountain and 20 at Maïdo-Grand Bénare, which is close to double the extreme UV index threshold <a href="https://www.who.int/uv/intersunprogramme/activities/en/uvcodes.jpg">defined</a> by the WHO. </p>
<p>The study also measured cumulative standard erythemal dose (SED), a measure of UV exposure in terms of joules per square metre.</p>
<p>The field measurement indicated that people were exposed to 40 SED when hiking Table Mountain and 64 when hiking Maïdo-Grand Bénare. These doses correspond to 3 to 25 times the minimal dose required to elicit a sunburn response depending on skin type (lighter skin requires a smaller dose while darker skin requires a larger dose).</p>
<p>Information about the <a href="https://www.mdpi.com/545770">climate</a> of the two sites shows that the total daily dose is extremely high during summer in Cape Town, and all year around in Reunion Island. Total daily dose is above the level where all skin types will experience sunburn, although people with deeply pigmented skin are less affected. These extreme exposures increase <a href="https://www.sciencedirect.com/science/article/pii/S0079610706000137">the risk</a> of cataracts, immunodeficiency and melanoma – at least for people with white skin. The link between sunburn and these health risks is not known for people with dark skin.</p>
<p>Melanoma is a type of skin cancer. The mean melanoma rate worldwide in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5575560/">2015</a> (male and female mixed) was five per 100,000. In South Africa, <a href="http://www.samj.org.za/index.php/samj/article/view/12576">the melanoma rate</a> for the total population, regardless of skin type, is five per 100,000 people for men and three per 100,000 for women. Among white South Africans, the melanoma rate is about 20 per 100,000 for men and 16 per 100,000 for women, which is similar to some of the rates recorded in Australia. </p>
<p><a href="https://www.em-consulte.com/es/article/1095782/donnees-epidemiologiques-des-melanomes-cutanes-a-l">From 2006 to 2015</a>, the male population of Reunion Island saw an increase in skin diseases from 2.7 to 7.1 cases per 100,000 people while cases in the female population surged from 3.0 to 6.1 per 100,000. These increasing rates may be due to an <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697050/">atmospheric change</a> and a human behaviour change (such as the popularity of <a href="https://www.sciencedirect.com/science/article/abs/pii/S0190962203000215">suntanning</a> for aesthetic reasons). </p>
<h2>Cover up</h2>
<p>The results of our tests highlight the importance of public awareness and prevention of the <a href="https://www.who.int/uv/publications/en/UVIGuide.pdf">risks related to UV</a>, especially at exposed sites like Table Mountain and Maïdo-Grand Bénare. The <a href="https://www.who.int/uv/intersunprogramme/activities/uv_index/en/index1.html">WHO</a> recommends that people avoid being outside in the middle of the day and wear long-sleeved shirts, hats, sunglasses and sunscreen.</p>
<p>This is particularly important in <a href="https://www.atmos-chem-phys.net/19/10087/2019/">tropical regions</a>, where there are several factors that can increase UV radiation: being relatively close to the Equator, low ozone, low aerosols, low solar zenith angle and clouds.</p><img src="https://counter.theconversation.com/content/136890/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This research was funded jointly by the CNRS (Centre National de la Recherche Scientifique) and the NRF (National Research Foundation) in the framework of the International Research Project ARSAIO and by the South Africa - France PHC-Protea Program (project No 42470VA).</span></em></p><p class="fine-print"><em><span>Caradee Yael Wright receives funding from the South African Medical Research Council and the National Research Foundation of South Africa. </span></em></p><p class="fine-print"><em><span>This research was funded jointly by the CNRS (Centre National de la Recherche Scientifique) and the NRF (National Research Foundation) in the framework of the International Research Project ARSAIO and by the South Africa - France PHC-Protea Program (project No 42470VA)</span></em></p>Too much ultraviolet radiation is dangerous for human health. Excessive exposure can cause skin ageing and sunburn and can induce melanoma, cataracts, ocular melanoma, and immunodeficiency.Jean-Maurice Cadet, PhD Candidate, Université de la RéunionCaradee Yael Wright, Specialist Scientist (Public Health), South African Medical Research CouncilHassan Bencherif, Professor, Université de la RéunionLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1250692019-10-11T09:38:32Z2019-10-11T09:38:32ZWhat science tells us about fire hazards facing Cape Town and its surrounds<figure><img src="https://images.theconversation.com/files/296410/original/file-20191010-188819-xmrl54.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A fire rages through wetlands close to Cape Town in February 2017.</span> <span class="attribution"><span class="source">EPA/Nic Bothma</span></span></figcaption></figure><p>South Africa’s Cape Peninsula – home to the picturesque city of Cape Town – is part of the only region in the world with fynbos. Fynbos is the world’s <a href="https://thefynbosguy.com/fynbos-easy-introduction/">most diverse vegetation type</a> – even more so than tropical rainforests. </p>
<p>Cape Town city surrounds the Cape Peninsula, the south-western extremity of the African continent, the remaining natural areas forming part of Table Mountain National Park. </p>
<p>The city has encroached ever closer to nature, developing deeper into the mountain fynbos. Alien plantations have resulted in <a href="https://theconversation.com/invasive-alien-plants-in-south-africa-pose-huge-risks-but-they-can-be-stopped-94186">infestations of alien trees</a>. Some citizens have been careless with inappropriate construction on the urban edge by building too high up on the mountains. </p>
<p>On top of this, various factors have resulted in a failure to maintain the desired fire regime, particularly of fires at 12-15 year intervals. As a result there has been a dangerous build-up of vegetation – fuel loads – in some places. </p>
<p>The Western Cape is entering the summer season – its driest, given that rains fall in the winter. <a href="https://www.iol.co.za/capeargus/news/cape-faces-fire-catastrophe-as-experts-fear-citys-worst-fire-season-lies-ahead-33176036">Fears have been mounting</a> that this year’s fire season might be the worst on record. </p>
<p>As a group of climate scientists and fynbos ecologists, we provide some context and background to the threat, based on available scientific research. We also point to what steps can be taken to help mitigate runaway fires in the region.</p>
<h2>Fynbos and fire</h2>
<p>Fynbos is both <a href="https://www.researchgate.net/publication/248531724_Managing_fires_on_the_Cape_Peninsula_Dealing_with_the_inevitable">fire-dependent and fire-prone</a>. The Cape’s incredibly biodiverse fynbos plants need fire to survive and thrive. Fynbos animals have likewise adapted their life cycles to fire. For example, baby tortoises that hatch after the fire season with the first rains rely on the flush of green to survive.</p>
<p>Fynbos requires a burn every <a href="https://pdfs.semanticscholar.org/1dee/1185429d1ca8a7608e528a293559b55db436.pdf">12-15 years on average</a>, otherwise species can be lost. Fires at shorter intervals (for example, less than seven to eight years) would eliminate many shrub species, while longer intervals between fires (over 30 years) cause senescence and die-off.</p>
<p>For example, South Africa’s iconic proteas are threatened by too-frequent fires because they need time to <a href="http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000600005">build up seed reserves</a>. And sunbirds and sugarbirds are threatened because they <a href="https://www.researchgate.net/publication/225445942_Reduced_flower_visitation_by_nectar-feeding_birds_in_response_to_fire_in_Cape_fynbos_vegetation_South_Africa">require older fynbos as habitat</a>.</p>
<p>Fire frequency is not the only important factor. Season and weather conditions are also important. These affect fire intensity, which is important in stimulating germination of seeds stored in the soil. </p>
<h2>Risk factors</h2>
<p>Fire hazard is <a href="https://www.frames.gov/documents/behaveplus/publications/Countryman_1972_TheFireEnvironmentConcept_ocr.pdf">influenced by three factors</a>: fuel loads, the weather and an ignition source (such as lightning, cigarette butts or arson).</p>
<p>The danger of fires in the Cape region this season is therefore partly dependent on how the fynbos has been managed over the past few decades. Good management includes promoting natural fire regimes and maintenance of fire belts. </p>
<p>If we have managed fynbos well, an ignition point will not become a disaster.
Under what conditions might ignition prove dangerous? When there are high fuel loads with suitable fire weather, this can result in disastrously uncontrollable fires. </p>
<p>When do we get high fuel loads? In two scenarios: when fire has been suppressed in fynbos for too long, and when <a href="https://fireecology.springeropen.com/articles/10.1186/s42408-018-0001-0">alien trees</a> such as pines, wattle, hakea and gums have invaded fynbos.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/296409/original/file-20191010-188797-1ek2jwt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/296409/original/file-20191010-188797-1ek2jwt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/296409/original/file-20191010-188797-1ek2jwt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/296409/original/file-20191010-188797-1ek2jwt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/296409/original/file-20191010-188797-1ek2jwt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/296409/original/file-20191010-188797-1ek2jwt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/296409/original/file-20191010-188797-1ek2jwt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/296409/original/file-20191010-188797-1ek2jwt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Indigenous Fynbos burns in a bush fire next to the Atlantic Ocean in Misty Cliffs, Cape Town.</span>
<span class="attribution"><span class="source">EPA/Nic Bothma</span></span>
</figcaption>
</figure>
<h2>Areas of highest risk</h2>
<p>Given these factors, some areas of the Cape Peninsula constitute a higher fire hazard than others. The areas that <a href="http://www.photodestination.co.za/cape-aflame-cape-town-s-dance-with-fire.html">burned in a large fire in 2015</a> have lower fuel loads and thus pose little fire hazard. Areas that didn’t burn in the 2015 fire are a greater fire hazard.</p>
<p>The highest fire hazard of all would be the slopes above Kirstenbosch, Newlands and the Back Table (the back of Table Mountain), where fire has been <a href="https://www.ecologi.st/post/fire-shadows/">kept out</a> for over 40 years. Areas such as Cecilia and Tokai, on the urban edge of the southern suburbs of the city, with alien pine and gum plantations, are also a big hazard. </p>
<p>Given the magnitude of the fuel loads, ignition in these areas would likely result in a disastrous fire.</p>
<p>Fire weather is also important. Under perfect fire conditions, a fire would be unstoppable if it occurred in areas of high fuel loads. The <a href="http://www.auburn.edu/academic/forestry_wildlife/fire/weather_elements.htm">key weather drivers of fire hazard</a> include antecedent rainfall and soil moisture, temperature, relative humidity, wind speed and wind direction. These weather conditions play a role in the short lead-up to ignition, as well as when the fire is burning.</p>
<h2>Untangling natural variation and climate change</h2>
<p>There is also the issue of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5081606/pdf/pnas.201612926.pdf">anthropogenic climate change</a> – changes in climate brought about by human activities. </p>
<p>How might climate change affect fire hazard? The odds are good that this summer will be <a href="https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/joc.4849">warmer than the average summer 20 years ago</a>. This is because global warming is making the average climate warmer by around <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/wcc.295">0.2°C per decade</a>. </p>
<p>But this is also true of recent preceding years, for example between 2015 and 2018. There is no evidence from a climatic point of view that this next fire season will have a higher hazard in terms of temperature than the past few years.</p>
<p>Most climate model projections agree that the Cape will <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/wcc.295">become drier in future</a>. But <a href="https://www.sajs.co.za/article/view/3952">observed trends up to now are insignificant and contradictory</a>. For example, a dry August and September may possibly leave vegetation this summer drier than in an average year. But, in fact, the Cape Town area is <a href="https://www.mdpi.com/2073-4441/9/11/876">much less dry than during the drought years of 2015-2017</a>.</p>
<p>When trying to understand anthropogenic climate change, we need to be able to separate it from natural variability. For example, if there is an active El Niño event, most regions of the world will be <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014EO230013">warmer than normal</a>. To account for natural variability, we turn to seasonal forecasts.</p>
<p>Seasonal forecasts for this summer show varied results for temperature over the southwestern Cape. The <a href="http://www.weathersa.co.za/home/longrangeforecast">South African Weather Service</a> is suggesting a cooler than normal summer, and the <a href="https://www.ecmwf.int/en/forecasts/charts/catalogue/">European Centre</a> is indicating a warmer than average summer.</p>
<p>For rainfall this coming summer, where the occasional rain events might help reduce dryness in the fuel load, there is <a href="http://www.csag.uct.ac.za/2018/01/25/so-when-is-it-going-to-rain/">little skill</a> in seasonal forecasts. So it’s <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005GL023965">hard to say</a> whether a potential lack of rainfall during the summer will increase fire hazard.</p>
<p>In itself, this combination doesn’t suggest a significantly higher fire hazard next season than in previous years. Therefore there is no evidence to suggest that the next fire season in the Cape will be anything out of the ordinary. </p>
<p>Despite this, we should still be taking precautions.</p>
<h2>Precautions</h2>
<p>We suggest three actions: clear, manage and educate.</p>
<p>“Clear” refers to the removal of alien trees. Local residents can join alien clearing groups in their area. “Manage” refers to the need to support authorities on the Cape Peninsula – such as SANParks – to manage fynbos appropriately. This includes ensuring that, on average, 12-15 year prescribed burns happen. </p>
<p>And finally, education is needed to ensure that people understand climate variability versus climate change, as well as the relationship between fynbos and fires, so that future disasters can be avoided.</p><img src="https://counter.theconversation.com/content/125069/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alanna Rebelo receives funding for her postdoctoral research from the Danish International Development Agency (DANIDA).
Alanna Rebelo volunteers for the WESSA-affiliated Friends of Tokai Park community organisation. </span></em></p><p class="fine-print"><em><span>David Carlyle Le Maitre receives funding via contract research work as a Principal Researcher with the CSIR in Stellenbosch. He receives contract funding from various sources including the DEFF Natural Resources Managment Programmes and the Department of Environmental Affairs and Development Planning in the Western Cape.</span></em></p><p class="fine-print"><em><span>Mark New receives funding from the AXA Research Fund, the BNP Paribas Foundation's Climate Initiative, the International Development Research Centre, DANIDA and the National Research Foundation of South Africa, among others.</span></em></p><p class="fine-print"><em><span>Peter Johnston receives funding from the Water Research Commission and Australia Africa Universities Network.</span></em></p><p class="fine-print"><em><span>Petra Holden receives funding for her postdoctoral research from the Danish International Development Agency (DANIDA), the AXA Research Fund, and the BNP Paribas Foundation's Climate Initiative.</span></em></p><p class="fine-print"><em><span>Tiro Nkemelang receives funding from the AXA Research Fund.</span></em></p><p class="fine-print"><em><span>Tony Rebelo is affiliated with Friends of Tokai Park (a WESSA Friends group), Custodians of Rare and Endangered Wildflowers, SANParks Honorary Rangers, Western Leopard Toad Conservation Committee (chair), Botanical Society of South Africa, and is a researcher at the South African National Biodiversity Institute, Kirstenbosch, in the fields of Citizen Science, Restoration Ecology, Conservation Planning and Ecology. All my research funding, and intern support, is via SANBI.</span></em></p>The danger of fires in the Cape region this season is partly dependent on how the Fynbos has been managed over the past few decades.Alanna Rebelo, Postdoctoral researcher, Stellenbosch UniversityDavid Carlyle Le Maitre, Principal Researcher Ecosystem services assessment and mapping, Council for Scientific and Industrial ResearchMark New, Director, African Climate and Development Initiative, University of Cape TownPeter Johnston, Climate Scientist and Researcher, University of Cape TownPetra Brigitte Holden, Postdoctoral Research Fellow, University of Cape TownTiro Nkemelang, PhD student in African Climate Risk, University of Cape TownTony Rebelo, Scientist, South African National Biodiversity InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1177652019-05-29T13:40:23Z2019-05-29T13:40:23ZHow we found out that rat poisons are killing wildlife in Cape Town<figure><img src="https://images.theconversation.com/files/276784/original/file-20190528-42576-1ohldel.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Caracals that feed on poisoned rodents in Cape Town pass the toxins onto their young through contaminated milk. </span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Wildlife near cities face many dangers. Some are easy to detect, such as when new developments destroy natural habitat. Others are less obvious. </p>
<p>For example, rat poisons are a useful tool for controlling a common household problem. But many who use them don’t realise that they have dangerous side effects for wildlife. </p>
<p>Rat poisons are designed to work slowly in their target species, rats, so that they ingest lethal doses of the poisons. The rats then become sick and increasingly toxic over a period of days or weeks. Poisoned rats then become easy, highly toxic prey for predators. </p>
<p>The side effects of exposure to these poison compounds are especially worrying for local wildlife in Cape Town, South Africa. The city is situated within a global biodiversity hotspot that includes the world-renowned Table Mountain National Park. Here, with thousands of plant species already <a href="https://www.sanparks.org/parks/table_mountain/conservation/heritage.php">threatened</a> by habitat loss and modification, the poisoning of numerous predatory wildlife species that help retain ecosystem stability could disrupt the delicate ecological balance. </p>
<p>Using samples from seven species, scientists from the <a href="http://www.icwild.uct.ac.za/">Institute for Communities and Wildlife in Africa</a> at the University of Cape Town <a href="https://www.sciencedirect.com/science/article/pii/S0048969719306047#">investigated</a> just how frequently Table Mountain’s wild predators are exposed to rat poisons through their prey. </p>
<p>We detected five different commercially available rat poisons in the livers of 81% of the predators we tested. Predators included common ones such as genets, Cape Eagle owls, and water mongooses, and rarer ones such as caracals, otters, and a honey badger. The detection of rat poison in otters is especially interesting because it suggests that poisons used on land can make their way into the city’s streams, wetlands and estuaries. </p>
<p>Some wildlife species are already threatened by habitat loss, vehicle collisions, poaching, disease, and fire. Rat poisons make these populations even more vulnerable to local extinction. When many species are affected within a single ecosystem, the effects of the poison exposure can escalate to threaten the functioning of an entire ecosystem. </p>
<p>The finding of widespread toxic exposure to rat poison in Cape Town’s wildlife echo those for predatory species elsewhere in Europe and North America, such as <a href="https://www.ncbi.nlm.nih.gov/pubmed/29438955">polecats</a>, <a href="https://link.springer.com/article/10.1007/s00244-012-9771-6">owls and raptors</a>, <a href="https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1523-1739.2003.01458.x">coyotes</a>, <a href="https://digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=1144&context=cate">endangered kit foxes</a>, <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0040163">fishers</a>, and <a href="https://www.ncbi.nlm.nih.gov/pubmed/25707484">bobcats</a>. For some of these species, anticoagulants are named as a leading cause of death and are even linked with at least one dramatic population decline in a species similar to caracals, the North American <a href="https://www.ncbi.nlm.nih.gov/pubmed/29343604">bobcat</a>. Researchers fear a similar fate for wildlife near Cape Town. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/276783/original/file-20190528-42565-d6wf74.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/276783/original/file-20190528-42565-d6wf74.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/276783/original/file-20190528-42565-d6wf74.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/276783/original/file-20190528-42565-d6wf74.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/276783/original/file-20190528-42565-d6wf74.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/276783/original/file-20190528-42565-d6wf74.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/276783/original/file-20190528-42565-d6wf74.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A study conducted in Cape Town found that 92% of caracals had rat poisons in their livers.</span>
<span class="attribution"><span class="source">Provided by author</span></span>
</figcaption>
</figure>
<h2>Multiple species exposed to rat poisons</h2>
<p>In vertebrates – animals that have a backbone or spinal column – the liver is the organ responsible for removing toxins from the blood. This is where we looked for evidence of rat poison exposure. One challenge was that testing the liver meant we could only sample animals that were already dead, limiting how many animals we could assess. </p>
<p>To better understand how Cape Town’s local predators come into contact with poisoned rats, we explored the rich <a href="http://www.urbancaracal.org/publications">data</a> set of the <a href="http://www.urbancaracal.org/">Urban Caracal Project</a>, which included liver samples from 24 caracals. </p>
<p>Alarmingly, 92% of caracals had rat poisons in their livers. But the amount of poison in their livers varied. Caracals that frequented vineyards had the highest levels. This may be because vineyards allow caracals a safe space to hunt close to the urban edge – where rat poisons are widespread. </p>
<p>But rat poisons are also affecting caracals that have never even seen a rodent. Our analysis also revealed a caracal kitten as having very high levels of poisons. It appears that mothers may inadvertently poison their own young through contaminated milk.</p>
<h2>A widespread problem</h2>
<p>With greater economic opportunities in cities, rapid urbanisation is a reality. The challenges of managing waste and the animals it attracts, are rapidly mounting. </p>
<p>Using poisons is quick but dirty from a wildlife perspective: the ultimate price will be paid by those animals at the top of the peri-urban food chain, such as leopards and caracals. </p>
<p>Raising awareness about this is the first step. Ensuring the conservation of urban wildlife needs changes in the way that people understand their individual impact on local ecosystems. </p>
<p>As consumers, people need more eco-friendly alternatives to rat poison. Nevertheless, the simplest solution is well within everyone’s reach: improve the management of waste which attracts rats in the first place. </p>
<p>Households can make a choice about whether they use poisons in or around their homes. In other parts of the world similar research <a href="https://www.ncbi.nlm.nih.gov/pubmed/25707484">findings</a> have galvanised the public and spurred <a href="https://www.cdpr.ca.gov/docs/registration/reevaluation/2018_investigation_anticoagulant.pdf">regulations</a> on the use of these poisons. </p>
<p>We hope these research findings will stimulate a similar dialogue with home owners, businesses, and municipal authorities on how to reduce environmental contamination by rat poisons and other toxins in Cape Town and beyond.</p><img src="https://counter.theconversation.com/content/117765/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Laurel Serieys receives funding from the University of Cape Town. Additional funding to support her research has come from the Claude Leon Foundation, private donors, Experiment Crowd Funding, Stellenbosch University, the University of California, Los Angeles, and the Cape Leopard Trust</span></em></p><p class="fine-print"><em><span>Jacqueline Bishop receives funding from the University of Cape Town and the South African National Research Foundation. </span></em></p>Household rat poison is endangering caracals, and other wildlife species in Cape Town, that prey on poisoned rodents. If not managed, this can negatively alter the region’s ecosystem.Laurel Serieys, Postdoctoral Fellow - University of California and Institute for Communities and Wildlife, University of Cape TownJacqueline Bishop, Senior Lecturer in Conservation Genetics, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/873732017-11-19T09:17:52Z2017-11-19T09:17:52ZCitizen science: how ordinary people can guard Cape Town’s biodiversity<figure><img src="https://images.theconversation.com/files/194837/original/file-20171115-19823-9t3g8p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Citizen scientists collecting soil and fine-roots from under unhealthy plants. </span> <span class="attribution"><span class="source">Cape Citizen Science</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Right now, you might be harbouring a killer: one so small it’s hidden in the sole of your hiking shoes. These tiny murderers won’t harm you in the short term, but they can be deadly for the plants that are crucial to food security and biodiversity conservation. </p>
<p><a href="http://rdcu.be/yjo0">New research</a> we conducted with our colleagues shows that some of these plant-killing microbes, known as <em>Phytophthora</em>, can be detected in urban areas before they get the chance to escape and spread into the natural environment. <em>Phytophthora</em> is a Greek word that best translates to “plant destroyer”. Species in this group are responsible for some of the worst plant disease epidemics in history. The <a href="https://www.britannica.com/event/Great-Famine-Irish-history">Irish Potato Famine</a> in the mid 1800s was caused by <em>Phytophthora infestans</em>, a species that still plagues tomato and potato fields around the world. </p>
<p>Another species, <em>Phytophthora cinnamomi</em>, is known as the “biological bulldozer” in Australia. It has affected thousands of plant species and is considered a top environmental threat. It also occurs in the Cape Floral Kingdom of southwestern South Africa, a hugely important biodiversity hot spot that encompasses the city of Cape Town. Thanks to citizen scientists engaged as <a href="https://theconversation.com/pathogen-hunters-citizen-scientists-track-plant-diseases-to-save-species-73710">pathogen hunters</a>, we have also learned that other “plant destroyers” are present in the Cape Floral Kingdom.</p>
<p>Many professional staff members from botanical gardens, nature reserves and national parks have already contributed to the project’s findings in the natural areas surrounding Cape Town. Now we’re asking citizens to help look for plant destroyers in the city’s urban areas.</p>
<p>This study is important because our best chance of preventing a plant disease epidemic is to detect the species before it spreads into natural or agricultural environments. Humans – the very “carriers” who can spread dangerous microbes unthinkingly from their equipment and shoes – can instead become the first line of defence against a possible microscopic invasion. </p>
<h2>Dangerous species on the move</h2>
<p>Cape Citizen Science is a project supported by the DST-NRF <a href="https://fabinet.up.ac.za/index.php/research-groups/dst-nrf-centre-of-excellence-in-tree-health-biotechnology">Centre of Excellence in Tree Health Biotechnology</a>, the <a href="https://www.fabinet.up.ac.za/">Forestry and Agricultural Biotechnology Institute</a> at the University of Pretoria, and Stellenbosch University. </p>
<p>It engages non-scientists in ecological and microbiological research. Currently the project facilitates research about the diversity and distribution of <em>Phytophthora</em> species in the Cape Floral Kingdom. The results provide baseline knowledge about the plant destroyers already present in natural areas. But we fear that other species, which have not yet “escaped”, may be hiding in urban areas. </p>
<p>We suspect most of these species are limited to the soil. That means they can’t “escape” unless the soil or infected plant tissues from the same area are moved. The worst case scenario would be the discovery of a wind-dispersed species such as <em>Phytophthora ramorum</em> – the organism that causes <a href="http://suddenoakdeath.org/">Sudden Oak Death</a> in the US. Finding these kinds of species before they can be blown away is important.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/PKSI1sxHiEc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Citizen scientists conducting research.</span></figcaption>
</figure>
<p>Our research suggests that surveys in urban environments could lead to the detection of <em>Phytophthora</em> species before they escape into the natural environment. Preventing their escape or spread is critical for preventing the damage these “destroyers” can do in natural or agricultural settings.</p>
<h2>Biodiversity protectors</h2>
<p>This is why we’ve launched a new phase of Cape Citizen Science called “The Cape Town Hypothesis Test”. A hypothesis is an idea that can be tested scientifically. In this case, we hypothesise that there are different <em>Phytophthora</em> species in Cape Town’s urban areas than there are in the area on and around Table Mountain National Park, a <a href="https://www.sanparks.org/parks/table_mountain/conservation/heritage.php">world heritage site</a> that’s a major part of the Cape Floral Kingdom.</p>
<p>Citizens participating in the project could be the first to discover a new introduction of a <em>Phytophthora</em> species in South Africa. Detecting such a species before it spreads to the natural environment is critical for protecting South Africa’s incredible biodiversity and preventing destruction from other potential “biological bulldozers”. If a different species is detected in the urban areas then local communities, researchers, stakeholders and officials can prevent the spread into natural areas. </p>
<p>From November 2017 until the end of February 2018 we’re seeking ordinary people’s help to test our hypothesis. This involves the collection of soil and fine roots from under sick plants in Cape Town’s urban areas. Instructions and examples of sick plants have been made <a href="http://citsci.co.za/capetown">available online</a>. Samples will then be tested in a laboratory at Stellenbosch University for the presence of a <em>Phytophthora</em> species.</p>
<p>We have also designated 15 important areas to collect samples. A map of these areas is available on the <a href="http://citsci.co.za/capetown">website</a>. Once a sample is submitted from one of those areas, the map areas will change colours and a GPS point will be added with the citizen’s name (if they wish). By sampling these areas, the study will ensure broad coverage of Cape Town’s urban areas.</p>
<p>Testing hypotheses is an important part of scientific research. The results of this study can be used to inform decisions to protect the natural areas surrounding the mother city. For example, finding a different species in the urban areas may be enough to justify boot cleaning stations at the base of the <a href="http://www.tablemountain.net/">Table Mountain Aerial Cableway</a> – a way to keep those tiny murderers from “hitch hiking” into natural and agricultural areas on our boots.</p><img src="https://counter.theconversation.com/content/87373/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joey Hulbert receives funding from the University of Pretoria and Cape Citizen Science benefits from support provided by the DST-NRF Centre of Excellence in Tree Health Biotechnology and the Forestry and Agricultural Biotechnology Institute. </span></em></p><p class="fine-print"><em><span>Francois Roets works for the Department of Conservation Ecology and Entomology, Stellenbosch University. He receives funding from the South African Department of Science and Technology/National Research Foundation Center of Excellence in Tree Health Biotechnology. </span></em></p>Humans - the very “carriers” who can spread dangerous microbes unthinkingly from their equipment and shoes - can instead become the first line of defence against a possible microscopic invasion.Joey Hulbert, PhD Student, University of PretoriaFrancois Roets, Senior lecturer, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/699142016-12-11T06:18:04Z2016-12-11T06:18:04ZHow we learned to listen to elusive, threatened frogs<figure><img src="https://images.theconversation.com/files/148908/original/image-20161206-25738-16zp2hx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Cape peninsula moss frog is smaller than 20mm and is, therefore, hard to monitor.</span> <span class="attribution"><span class="source">Francois Becker</span></span></figcaption></figure><p>Scientists the world over have a frog problem: we have little idea of how many frogs there are in each species in the world. This means that we are unable to predict how many there will be in the future due, for example, to the effects of climate change.</p>
<p>There have been very few studies recording the size of amphibian populations. So those of us studying amphibians have very little with which to work. What we do know is that many frogs are under threat mostly from habitat change, but also from disease. In southern Africa they are particularly vulnerable to <a href="http://john.measey.com/media/545057e1-8025-4abd-9aa7-3a90f470dd01/NgmUbw/PDFs/Measey_2011_Ensuring.pdf">invasive species</a>.</p>
<p>Male frogs advertise their presence with species specific mating calls. Determining their presence has traditionally entailed listening for these calls. If you want to know how many frogs are calling, then stand with your hands behind your ears and try to count all the animals you hear. It sounds simple, but it’s not that easy. I’ve tried. </p>
<p>Listening to 10 calling animals is taxing. More than 10 and it’s possible to get muddled. Choruses of over 50 sound like noise. </p>
<p>Luckily the revolution in digital media has helped those of us studying amphibians. We’re able to monitor vocalising species and record a large number of sounds from the environment. Automated computer software, like voice recognition on smart phones, can then pick out particular species from their calls. Acoustic monitoring is ideal for monitoring the abundance of a species over time, as it has minimal impact on the species being monitored. </p>
<p>But what then? Interpreting the number of calls is problematic for several reasons. First and foremost is the fact that the area a microphone listens to is not defined. The vagaries of the acoustic environment mean that the slightest wind, or even a change in humidity, can affect the distance over which sound propagates. This means that microphones listen to different areas every time they record.</p>
<p>Recently <a href="http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12810/full">published research</a> by my colleagues and I could change this. It provides a methodology for acoustic monitoring that calculates the area listened to by an array of microphones, as well as estimating the number of calls made in that area. This has important implications for acoustic monitoring – and for attempts to catalogue just how many frogs are “ribbiting” around us. </p>
<h2>A new methodology</h2>
<p>We used microphones to monitor the Cape peninsula moss frog (<em>Arthroleptella lightfooti</em>) in Table Mountain National Park, South Africa. These frogs are endemic to the area and occur nowhere else on the planet. They are listed as “<a href="http://www.iucnredlist.org/details/58061/0">Near Threatened</a>” on the IUCN list of threatened species. Any data we can glean will contribute to their conservation. </p>
<p>We used an array of six microphones to monitor populations of Cape peninsula moss frogs over their winter breeding season from May to October. </p>
<p>Researchers have previously used time of arrival of sound at each microphone in an array to determine the position <a href="https://youtu.be/JTYFYtZJXro">of calling animals</a>. </p>
<p>We used a novel statistical technique developed by co-author statisticians Stevenson and Borchers (<a href="http://john.measey.com/ascr">Spatial Capture Recapture: SCR</a>) to analyse the automated call data. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.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"></a>
<figcaption>
<span class="caption">Listening for calls of the endangered Arthroleptella subvoce to monitor its abundance in the Groot Winterhoek Wilderness Area, South Africa.</span>
<span class="attribution"><span class="source">John Measey</span></span>
</figcaption>
</figure>
<p>The analysis takes into account both microphones which hear calls and those which don’t hear calls, as well as the distance between microphones to build up an estimate of the number of calls and the <a href="https://youtu.be/JTYFYtZJXro">area from which the calls come</a>. For an encore, the statisticians combined the information from time of arrival and call amplitude difference with Spatial Capture Recapture to build the first ever statistical estimate of the density of calling male frogs from an acoustic array.</p>
<p>We also recorded rainfall and temperature and were surprised to find that the number of frogs calling at each site didn’t relate to either of these factors. Instead, it started off with relatively few animals calling early in the season (May), built to a fine crescendo in July and then tailed off toward October.</p>
<p>More surprising was that the area in which the microphone array could detect frog calls nearly doubled (from 400 to 800 m₂) during the winter breeding season. But because the technique accounted for this change in the size of the sampling area we could effectively monitor the calling density of the species without having to worry about the changing areas that the microphones recorded.</p>
<h2>The new direction</h2>
<p>The idea of using an array of microphones is not new. Using the time of arrival of sounds to each microphone to determine the presence of a calling animal, such as a frog, is old hat. The technique we’ve <a href="http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12810/full">pioneered</a> provides a new direction for acoustic monitoring because we were able to define the area in which the microphone array was detecting calls. </p>
<p>The study has produced a robust technique for estimating call density. This is because it combined the statistical wizardry that allowed estimates from Spatial Capture Recapture with the time of arrival and signal strength. That combination makes it possible to increase the accuracy of the estimate of call density.</p>
<p>Researchers wishing to take advantage of the wonders of digital media to monitor species at risk of climate change, <a href="https://theconversation.com/the-future-for-frogs-looks-bleak-unless-humans-change-their-habits-57505">like frogs</a>, can now use a technique that will give them call density which can be compared across recording occasions. </p>
<p>This will contribute to our understanding of how threatened species which vocalise are faring on our changing planet.</p><img src="https://counter.theconversation.com/content/69914/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Measey receives funding from National Geographic, the Centre for Invasion Biology (CIB), and the National Research Foundation (NRF). </span></em></p>A robust technique using the wonders of digital media has helped researchers understand how threatened species like frogs are faring on our globally changing planet.John Measey, Senior Researcher at the CIB based in the Department of Botany and Zoology, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/655122016-10-02T19:36:31Z2016-10-02T19:36:31ZProtecting biodiversity: people’s buy-in is as important as the science<figure><img src="https://images.theconversation.com/files/139884/original/image-20160930-9922-nmqtyg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">South Africa's Proteaceae family, makes up a part of fynbos, a floral region with plants unique to South Africa Cape Town's Table Mountain National Park.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Biodiversity, the variety of life on earth (plants, animals and the ecosystems in which they live), underpins the planet’s life support systems and consequently human well-being. Unprecedented, large-scale biodiversity loss currently threatens the sustainability of these systems, such as the sustained supply of clean water.</p>
<p>As part of a global response numerous international agreements provide road maps for effective and urgent action. For example 196 countries, as signatories to the <a href="https://www.cbd.int/convention/">Convention on Biological Diversity</a>, have agreed to a set of targets that would contribute to slowing the loss of biodiversity globally. But conserving biodiversity is not enough. Focus is also needed on restoring damaged and degraded habitats. </p>
<p>South Africa has <a href="https://www.cbd.int/doc/strategic-plan/targets/T15-quick-guide-en.pdf">committed to</a> restore at least 15% of degraded ecosystems by 2020. The complex task of getting the job done has begun. But as with most things, the devil is in the detail.</p>
<p>Conservation success has a great deal to do with understanding the biology of habitats and species. But it is also about understanding the role that people play in the landscape, and the values they hold. </p>
<p>These issues tend to erupt where urban areas interface with nature, because the boundaries are unpredictable and risky and involve many competing views and values. </p>
<p>The polarised battle playing out in Tokai Park in the Western Cape is a microcosm of the world of potential conflict where natural environment interfaces with multiple social values. Here the tension is between those who want to remove pine trees to create space to restore a threatened indigenous plant community, and those who want the pine tree plantation to remain.</p>
<p>The Tokai Park debate, now in the realm of the courts, is a minor social issue in the context of the city. But it provides a window into the complex world of conservation where social issues intersect with ecology. So far efforts to find common ground have failed, highlighting how important it is to create conditions where opposing views can be debated, and common cause found in the fight to protect biodiversity. </p>
<h2>Two worlds collide</h2>
<p>Tokai Park is situated at the interface between urban development and one of the world’s most globally iconic habitats, <a href="http://www.southafrica.net/za/en/articles/entry/article-southafrica.net-south-africas-fynbos">fynbos</a> - a floral region with plants unique to South Africa. Tokai Park forms part of Cape Town’s Table Mountain National Park and is managed by <a href="https://www.sanparks.org/parks/table_mountain/about/2007/tokai.php">SANPARKS</a>, a national conservation agency.</p>
<p>The region is home to unparalleled <a href="https://www.iucn.org/content/world%E2%80%99s-hottest-hot-spot-plant-diversity">fynbos plant diversity</a> and has been identified as a global biodiversity hot-spot. It is also haven for a dwindling specialised habitat with nowhere else to go, <a href="https://www.capetown.gov.za/en/EnvironmentalResourceManagement/publications/Documents/Biodiv_fact_sheet_06_CapeFlatsSandFyn_2011-03.pdf">Cape Flats Sand Fynbos</a>. </p>
<p><a href="https://www.capetown.gov.za/en/EnvironmentalResourceManagement/publications/Documents/Biodiv_fact_sheet_06_CapeFlatsSandFyn_2011-03.pdf">Urbanization</a> has nearly wiped out Cape Town’s Cape Flats Sand Fynbos. The last critically endangered habitat is uniquely confined to the city of Cape Town. </p>
<p>South Africa has committed, through global targets and international agreements such as the <a href="https://www.cbd.int/convention/">Convention on Biological Diversity</a>, to protect and restore remaining natural habitats. And the remnants of this, and other threatened habitats, have been a focus of conservation attention for the local conservation agencies. </p>
<p><a href="https://www.facebook.com/ParkscapeSA/?fref=ts">Parkscape</a>, a Cape Town community group, recently mobilised enough support to temporarily prevent conservation authorities from maintaining a pine plantation in the specialised habitat.</p>
<p>Pines have been planted in the Cape over centuries. But their competitive dominance over fynbos and their water-guzzling ways have made them uncomfortable conservation companions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=513&fit=crop&dpr=1 754w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=513&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=513&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pines in the Tokai park have a competitive dominance over fynbos and their water-guzzling ways have made them uncomfortable conservation companions.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>So the chance to return a pine stand at the end of its commercial lifespan to its former fynbos-diverse natural glory seemed like a win-win solution. </p>
<p>But a fierce, largely middle class, lobby has put its weight behind retaining the non-native pines. The two sides have gone to court to try and settle the matter.</p>
<p>The commercial pine plantation is used for riding horses, walking dogs and a picnic spot in the summer. The small, well-resourced group defending it has garnered enough support to stay the fate of the pine trees. </p>
<p>Exchanges on <a href="https://www.facebook.com/ParkscapeSA/?fref=ts">social media</a> provide an insight into the many ethical and moral values tied up in the <a href="https://www.facebook.com/FriendsOfTokaiPark/">issue</a>. </p>
<p>There are those who argue that the area will become a magnet for criminals, citing a murder that occurred in nearby fynbos. Others are sentimental about the forest because it’s where they find solace and shade. Both sides point to the fact that pines as well as fynbos are sources of value such as medicines and wood. </p>
<p>But some key questions need to be asked. These include: can shade be provided in alternative ways? The answer is certainly yes. Native trees can provide suitable shade too. How fair is it to associate all future crime with restored fynbos? Crime happens everywhere. Cape Flats Sand Fynbos may well be a victim of crime-by-association.</p>
<h2>A way out of the impasse</h2>
<p>It is clear that conservation agencies have difficulty doing their work when social conflicts erupt.</p>
<p>The answer lies in concerted action to work with people who hold alternative views. In doing so, and by acknowledging their views, commonality can often be found. </p>
<p>But how can this be achieved? </p>
<p>Conservation agendas will only be advanced if people engaged in conservation can navigate social-ecological spaces and engage with multiple, often conflicting values, to try and find common ground.</p>
<p>Our <a href="http://www.sun.ac.za/english/faculty/agri/conservation-ecology">teaching</a> and <a href="http://academic.sun.ac.za/cib/">research</a> at Stellenbosch University is focused on conservation in used environments. That means we think about applied problems that often require multiple perspectives to resolve. We expose our students to these multiple perspectives, sensitising them to the challenges of working in a social-ecological context. </p>
<p>But understanding how to conduct appropriate public participation requires more. </p>
<p>A blend of skills is needed, including public communication, conflict management and facilitation. But these are difficult to incorporate into science-based degrees. Training opportunities need to be scaled up as well as innovative interdisciplinary collaboration. </p>
<p>Ecological restoration brings with it a message of hope. By repairing habitat suited to other living organisms, the services provided by these habitats are also returned to us. But unless we can convince the people of its value, and mediate surrounding conflicts, we are doomed to fail.</p><img src="https://counter.theconversation.com/content/65512/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karen Joan Esler is affiliated with the DST NRF Centre for Invasion Biology at Stellenbosch University. </span></em></p>Restoring habitats have numerous benefits, they can also benefit humanity. But it is for people to be convinced that they can actually do good.Karen Joan Esler, Professor of Conservation Ecology and Head of the Department of Conservation Ecology & Entomology at Stellenbosch University, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.