tag:theconversation.com,2011:/us/topics/the-bahamas-75885/articlesThe Bahamas – The Conversation2022-11-28T13:33:32Ztag:theconversation.com,2011:article/1868992022-11-28T13:33:32Z2022-11-28T13:33:32ZWe’re decoding ancient hurricanes’ traces on the sea floor – and evidence from millennia of Atlantic storms is not good news for the coast<figure><img src="https://images.theconversation.com/files/490533/original/file-20221019-23-g61gcn.jpg?ixlib=rb-1.1.0&rect=323%2C871%2C3981%2C2433&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Deep 'blue holes,' like this one off Belize, can collect evidence of hurricanes.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Belize_Blue_Hole_(TMP)_(16912331906).jpg">The TerraMar Project</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>If you look back at the history of Atlantic hurricanes since the late 1800s, it might seem hurricane frequency is on the rise.</p>
<p>The year 2020 had the <a href="https://www.nhc.noaa.gov/data/tcr/index.php?season=2020&basin=atl">most tropical cyclones</a> in the Atlantic, with 31, and 2021 had the <a href="https://www.nhc.noaa.gov/data/tcr/index.php?season=2021&basin=atl">third-highest</a>, <a href="https://www.nhc.noaa.gov/climo/">after 2005</a>. The past decade saw <a href="https://en.wikipedia.org/wiki/List_of_costliest_Atlantic_hurricanes%22%22">five of the six</a> most destructive Atlantic hurricanes in modern history.</p>
<p>Then a year like 2022 comes along, with no major hurricane landfalls until <a href="https://theconversation.com/fiona-was-one-of-canadas-worst-natural-disasters-but-evacuations-prevented-greater-losses-in-atlantic-canada-191319">Fiona</a> <a href="https://www.washingtonpost.com/nation/2022/09/23/hurricane-fiona-puerto-rico-floods/">and</a> <a href="https://theconversation.com/hurricane-ian-flooded-a-hospital-and-forced-evacuations-from-dozens-of-nursing-homes-many-health-facilities-face-rising-risks-from-severe-storms-191648">Ian</a> struck in late September. The Atlantic hurricane season, which ended on Nov. 30, had <a href="https://www.nhc.noaa.gov/archive/2022/">eight hurricanes and 14 named storms</a>. It’s a reminder that small sample sizes can be misleading when assessing trends in hurricane behavior. There is so much natural variability in hurricane behavior year to year and even decade to decade that we need to look much further back in time for the real trends to come clear.</p>
<p>Fortunately, hurricanes leave behind telltale evidence that goes back millennia.</p>
<p>Two thousand years of this evidence indicates that the Atlantic has experienced even stormier periods in the past than we’ve seen in recent years. That’s not good news. It tells <a href="https://www.researchgate.net/profile/Tyler-Winkler-4">coastal oceanographers like me</a> that we may be significantly underestimating the threat hurricanes pose to Caribbean islands and the North American coast in the future. </p>
<h2>The natural records hurricanes leave behind</h2>
<p>When a hurricane nears land, its winds whip up powerful waves and currents that can sweep coarse sands and gravel into marshes and deep coastal ponds, sinkholes and lagoons.</p>
<p>Under normal conditions, fine sand and organic matter like leaves and seeds fall into these areas and settle to the bottom. So when coarse sand and gravel wash in, a distinct layer is left behind.</p>
<p>Imagine cutting through a layer cake – you can see each layer of frosting. Scientists can see the same effect by plunging a long tube into the bottom of these coastal marshes and ponds and pulling up several meters of sediment in what’s known as a sediment core. By studying the layers in sediment, we can see when coarse sand appeared, suggesting an extreme coastal flood from a hurricane.</p>
<p>With these sediment cores, we have been able to document evidence of Atlantic hurricane activity over thousands of years.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490544/original/file-20221019-17-2xeuk8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="One sediment core with dates showing high levels of sand deposits and a photo of one section showing the sand layer." src="https://images.theconversation.com/files/490544/original/file-20221019-17-2xeuk8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490544/original/file-20221019-17-2xeuk8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=842&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490544/original/file-20221019-17-2xeuk8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=842&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490544/original/file-20221019-17-2xeuk8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=842&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490544/original/file-20221019-17-2xeuk8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1058&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490544/original/file-20221019-17-2xeuk8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1058&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490544/original/file-20221019-17-2xeuk8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1058&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The red dots indicate large sand deposits going back about 1,060 years. The yellow dots are estimated dates from radiocarbon dating of small shells.</span>
<span class="attribution"><span class="source">Tyler Winkler</span></span>
</figcaption>
</figure>
<p>We now have dozens of chronologies of hurricane activity at different locations – including <a href="https://doi.org/10.1002/2014EF000274">New England</a>, the <a href="https://doi.org/10.1038/s41598-020-75874-0">Florida Gulf</a> <a href="https://doi.org/10.1016/j.margeo.2011.07.001">Coast</a>, the <a href="https://doi.org/10.1073/pnas.1519566113">Florida Keys</a> <a href="https://doi.org/10.1038/srep03876">and</a> <a href="https://doi.org/10.1016/j.quascirev.2020.106570">Belize</a> – that reveal decade- to century-scale patterns in hurricane frequency.</p>
<p>Others, including from <a href="https://doi.org/10.1029/2020GL089859">Atlantic</a> <a href="https://doi.org/10.1016/j.margeo.2018.09.012">Canada</a>, <a href="https://doi.org/10.2112/03-0103.1">North Carolina</a>, <a href="https://doi.org/10.1006/qres.2000.2166">northwestern Florida</a>, Mississippi and <a href="https://doi.org/10.1038/nature05834">Puerto Rico</a>, are lower-resolution, meaning it is nearly impossible to discern individual hurricane layers deposited within decades of one another. But they can be highly informative for determining the timing of the most intense hurricanes, which can have significant impacts on coastal ecosystems.</p>
<p>It’s the records from the Bahamas, however, with nearly annual resolution, that are crucial for seeing the long-term picture for the Atlantic Basin.</p>
<h2>Why The Bahamas are so important</h2>
<p>The Bahamas are exceptionally vulnerable to the impacts of major hurricanes because of their geographic location.</p>
<p>In the North Atlantic, 85% of all major hurricanes form in what is known as the <a href="https://www.wunderground.com/blog/JeffMasters/record-atlantic-ssts-continue-in-the-hurricane-main-development-region.html">Main Development Region</a>, off western Africa. Looking just at observed hurricane tracks from the past 170 years, my analysis shows that about 86% of major hurricanes that affect the Bahamas also form in that region, suggesting the frequency variability in the Bahamas may be representative of the basin.</p>
<figure class="align-center ">
<img alt="Satellite view of Atlantic showing tracks of each storm, most starting off Africa, heading west and then curving northward." src="https://images.theconversation.com/files/490696/original/file-20221019-18-y6wbyg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490696/original/file-20221019-18-y6wbyg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=336&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490696/original/file-20221019-18-y6wbyg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=336&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490696/original/file-20221019-18-y6wbyg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=336&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490696/original/file-20221019-18-y6wbyg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490696/original/file-20221019-18-y6wbyg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490696/original/file-20221019-18-y6wbyg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Atlantic hurricane tracks from 1851 to 2012.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Atlantic_hurricane_tracks.jpg">Nilfanion/Wikimedia</a></span>
</figcaption>
</figure>
<p>A substantial percentage of North Atlantic storms also <a href="https://www.nhc.noaa.gov/climo/images/1851_2017_allstorms.jpg">pass over or near these islands</a>, so these records appear to reflect changes in overall North Atlantic hurricane frequency through time.</p>
<p>By coupling coastal sediment records from the Bahamas with records from sites farther north, we can explore how changes in ocean surface temperatures, ocean currents, global-scale wind patterns and atmospheric pressure gradients affect regional hurricane frequency.</p>
<p>As sea surface temperatures rise, warmer water provides more energy that can fuel <a href="https://www.ipcc.ch/report/ar6/wg2/">more powerful and destructive</a> hurricanes. However, the frequency of hurricanes – how often they form – isn’t necessarily affected in the same way.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490539/original/file-20221019-25-jyn1fv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Satellite image of a hurricane over The Bahamas, marked on the map, next to Florida." src="https://images.theconversation.com/files/490539/original/file-20221019-25-jyn1fv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490539/original/file-20221019-25-jyn1fv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490539/original/file-20221019-25-jyn1fv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490539/original/file-20221019-25-jyn1fv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490539/original/file-20221019-25-jyn1fv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490539/original/file-20221019-25-jyn1fv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490539/original/file-20221019-25-jyn1fv.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"></a>
<figcaption>
<span class="caption">Hurricane Dorian sat over the Bahamas as a powerful Category 5 storm in 2019.</span>
<span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/images/145555/hurricane-dorian-pounds-the-bahamas">Laura Dauphin/NASA Earth Observatory</a></span>
</figcaption>
</figure>
<h2>The secrets hidden in blue holes</h2>
<p>Some of the best locations for studying past hurricane activity are large, near-shore sinkholes known as blue holes.</p>
<p>Blue holes get their name from their deep blue color. They formed when carbonate rock dissolved to form underwater caves. Eventually, the ceilings collapsed, leaving behind sinkholes. The Bahamas has thousands of blue holes, some as wide as a <a href="https://doi.org/10.1016/j.quascirev.2021.107126">third of a mile</a> and as deep as a <a href="http://www.deansbluehole.org/">60-story building</a>.</p>
<p>They tend to have deep vertical walls that can trap sediments – including sand <a href="https://hakaimagazine.com/news/blue-holes-show-hurricane-activity-in-the-bahamas-is-at-a-centuries-long-low/">transported by strong hurricanes</a>. Fortuitously, deep blue holes often have little oxygen at the bottom, which slows decay, helping to preserve organic matter in the sediment through time.</p>
<figure class="align-center ">
<img alt="Images showing the depth of a blue hole" src="https://images.theconversation.com/files/490518/original/file-20221019-21-pw980u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490518/original/file-20221019-21-pw980u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1032&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490518/original/file-20221019-21-pw980u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1032&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490518/original/file-20221019-21-pw980u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1032&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490518/original/file-20221019-21-pw980u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1296&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490518/original/file-20221019-21-pw980u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1296&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490518/original/file-20221019-21-pw980u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1296&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Hine’s Blue Hole in the Bahamas is about 330 feet (100 meters) deep. Seismic imaging shows about 200 feet (60-plus meters) of accumulated sediment.</span>
<span class="attribution"><span class="source">Pete van Hengstum; Tyler Winkler</span></span>
</figcaption>
</figure>
<h2>Cracking open a sediment core</h2>
<p>When we bring up a sediment core, the coarse sand layers are often evident to the naked eye. But closer examination can tell us much more about these hurricanes of the past.</p>
<p>I use X-rays to measure changes in the density of sediment, <a href="https://serc.carleton.edu/research_education/geochemsheets/techniques/XRF.html">X-ray fluorescence</a> to examine elemental changes that can reveal if sediment came from land or sea, and sediment textural analysis that examines the grain size.</p>
<p>To figure out the age of each layer, we typically use <a href="https://youtu.be/phZeE7Att_s">radiocarbon dating</a>. By measuring the amount of carbon-14, a radioactive isotope, in shells or other organic material found at various points in the core, I can create a statistical model that predicts the age of sediments throughout the core.</p>
<p>So far, my colleagues and I have published five paleohurricane records with nearly annual detail from blue holes on islands across the Bahamas. </p>
<p>Each record shows periods of significant increase in storm frequency lasting decades and sometimes centuries. </p>
<figure class="align-center ">
<img alt="A map showing hurricane frequency from 1850 to 2019, with parts of Florida, Louisiana and North Carolina showing nine to 10 storms." src="https://images.theconversation.com/files/490500/original/file-20221018-8290-siwwug.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490500/original/file-20221018-8290-siwwug.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490500/original/file-20221018-8290-siwwug.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490500/original/file-20221018-8290-siwwug.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490500/original/file-20221018-8290-siwwug.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=491&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490500/original/file-20221018-8290-siwwug.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=491&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490500/original/file-20221018-8290-siwwug.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=491&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The red dots show the sites of high-resolution paleohurricane records. The map shows the frequency of hurricanes ranked Category 2 or above from 1850 to 2019.</span>
<span class="attribution"><span class="source">Tyler Winkler</span></span>
</figcaption>
</figure>
<p>The records vary, showing that a single location might not reflect broader regional trends. </p>
<p>For example, <a href="https://doi.org/10.1038/s41598-020-73132-x">Thatchpoint Blue Hole</a> on Great Abaco Island in the northern Bahamas includes evidence of at least 13 hurricanes per century that were Category 2 or above between the years 1500 and 1670. That significantly exceeds the rate of nine per century documented since 1850. During the same period, 1500 to 1670, <a href="https://doi.org/10.1029/2019PA003665">blue holes at Andros Island</a>, just 186 miles (300 kilometers) south of Abaco, documented the lowest levels of local hurricane activity observed in this region during the past 1,500 years.</p>
<h2>Spotting patterns across the Atlantic Basin</h2>
<p>Together, however, these records offer a glimpse of broad regional patterns. They’re also giving us new insight into the ways ocean and atmospheric changes can influence hurricane frequency.</p>
<p>While rising sea surface temperatures provide more energy that can fuel <a href="https://www.ipcc.ch/report/ar6/wg2/">more powerful and destructive</a> hurricanes, their frequency – how often they form – isn’t necessarily affected in the same way. Some studies have predicted the total number of hurricanes will actually decrease in the future.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490490/original/file-20221018-7213-wkks8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Eight chronologies of hurricane evidence stacked to show corresponding periods of higher hurricane frequency." src="https://images.theconversation.com/files/490490/original/file-20221018-7213-wkks8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490490/original/file-20221018-7213-wkks8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1135&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490490/original/file-20221018-7213-wkks8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1135&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490490/original/file-20221018-7213-wkks8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1135&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490490/original/file-20221018-7213-wkks8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1427&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490490/original/file-20221018-7213-wkks8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1427&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490490/original/file-20221018-7213-wkks8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1427&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Comparing paleohurricane records from several locations shows periods of higher frequency. The highlighted periods cover the Little Ice Age, a time of cooler conditions in the North Atlantic from 1300 to 1850, and the Medieval Warm Period, from 900 to 1250.</span>
<span class="attribution"><span class="source">Tyler Winkler</span></span>
</figcaption>
</figure>
<p>The compiled Bahamian records document substantially higher hurricane frequency in the northern Caribbean during the <a href="https://eos.org/articles/the-little-ice-age-wasnt-global-but-current-climate-change-is">Little Ice Age</a>, around 1300 to 1850, than in the past 100 years.</p>
<p>That was a time when North Atlantic surface ocean temperatures were <a href="https://doi.org/10.1016/j.quascirev.2021.107126">generally cooler</a> <a href="https://doi.org/10.1016/j.margeo.2021.106653">than they are today</a>. But it also coincided with an intensified West African monsoon. The monsoon could have produced more thunderstorms off the western coast of Africa, which act as <a href="https://doi.org/10.1126/science.249.4974.1251">low-pressure seeds for hurricanes</a>.</p>
<p>Steering winds and vertical wind shear likely also affect a region’s hurricane frequency over time. The Little Ice Age active interval observed in most Bahamian records <a href="https://doi.org/10.1002/2014EF000274">coincides with increased</a> <a href="https://www.cambridge.org/core/journals/quaternary-research/article/barrier-island-response-to-late-holocene-climate-events-north-carolina-usa/BE735D1D3E624DF03F33E8FDC90701F8">hurricane strikes</a> along the U.S. Eastern Seaboard from 1500 to 1670, but at the same time it was a <a href="https://doi.org/10.1016/j.margeo.2011.07.001">quieter period in the Gulf</a> of Mexico, <a href="https://doi.org/10.1029/2019PA003665">central Bahamas</a> and <a href="https://doi.org/10.1038/srep03876">southern Caribbean</a>.</p>
<p>Records from sites farther north tell us more about the climate. That’s because changes in ocean temperature and climate conditions are likely far more important to controlling regional impacts in such areas as the Northeastern U.S. and Atlantic Canada, where cooler climate conditions are often unfavorable for storms.</p>
<h2>A warning for the islands</h2>
<p>I am currently developing records of coastal storminess in locations including Newfoundland and Mexico. With those records, we can better anticipate the impacts of future climate change on storm activity and coastal flooding.</p>
<p>In the Bahamas, meanwhile, sea level rise is putting the islands at increasing risk, so even weaker hurricanes can produce damaging flooding. Given that storms are expected to be more intense, any increase in storm frequency could have devastating impacts.</p><img src="https://counter.theconversation.com/content/186899/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tyler Winkler does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A look back at hurricane history suggests we may be significantly underestimating future risks.Tyler Winkler, Postdoctoral Researcher in Oceanography, Woods Hole Oceanographic InstitutionLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1512702020-12-09T19:04:10Z2020-12-09T19:04:10ZWe discovered a 115,000-year-old iguana nest fossil in the Bahamas<figure><img src="https://images.theconversation.com/files/373422/original/file-20201207-17-u9ozpb.png?ixlib=rb-1.1.0&rect=0%2C1%2C1180%2C879&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many species of iguanas dig shelters for protection against predators, fires and extreme weather. Most also make underground nests.</span> <span class="attribution"><span class="source">Anthony J. Martin</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>A pregnant iguana dug into a vegetated sand dune about 115,000 years ago on a small island in a chain of islands that one day would be called the Bahamas. Once she buried herself and was surrounded by loose sand, she scraped out a chamber and laid her eggs in it. On her way out of this underground nursery, she packed sand behind her, forming distinctive layers that marked her progress to the surface. </p>
<p>Once back in the sunshine, she tamped down the top to conceal the nest. Over many centuries, a thin layer of soil developed over the former nesting burrow, and minerals from that soil formed between the sand grains, turning the dune into limestone, which preserved the structure of the nesting burrow.</p>
<p>In December 2013, while exploring a roadcut on San Salvador Island in the Bahamas with 19 undergraduate geology students from Emory University, <a href="https://scholar.google.com/citations?hl=en&user=IgFQAgcAAAAJ">one of us</a> (Anthony) noticed this unusual structure in the rock. It turns out the road excavators had unwittingly exposed a section of ancient sand dune, containing this iguana burrow from long ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373117/original/file-20201204-17-1xk8x7t.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of the fossilized burrow side by side with a drawing showing an iguana having just completed building a nest." src="https://images.theconversation.com/files/373117/original/file-20201204-17-1xk8x7t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373117/original/file-20201204-17-1xk8x7t.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=254&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373117/original/file-20201204-17-1xk8x7t.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=254&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373117/original/file-20201204-17-1xk8x7t.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=254&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373117/original/file-20201204-17-1xk8x7t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=319&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373117/original/file-20201204-17-1xk8x7t.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=319&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373117/original/file-20201204-17-1xk8x7t.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=319&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An iguana from long ago carefully constructed this nest layer by layer.</span>
<span class="attribution"><span class="source">Anthony J. Martin</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Over the next six years, with contributions from undergraduates and the <a href="https://digitalscholarship.emory.edu/">Emory Center for Digital Scholarship</a>, we were able to conclude that we’d found not only the <a href="https://doi.org/10.1371/journal.pone.0242935">first known fossil iguana nesting burrow</a>, but also the first trace fossil attributed to an iguana. Based on its geologic setting, we estimate the burrow is about 115,000 years old, placing it in the Late Pleistocene Epoch, which is best known for its ice ages and megafauna, like mammoths and giant ground sloths.</p>
<h2>Trace fossils</h2>
<p>A trace fossil is indirect evidence of ancient life made while an organism was alive. The study of this iguana burrow and other trace fossils, such as tracks, nests, tooth impressions and feces, fall under the science of ichnology.</p>
<p>Trace fossils are important because they directly reflect ancient behavior. Also, unlike bones or shells, which are often moved after an animal’s death, most trace fossils are found exactly where they were created. </p>
<p>Trace fossils offer a unique window to the distant past. <a href="https://doi.org/10.1371/journal.pone.0004591">When a dinosaur sat down alongside a lake shore</a> in modern-day Utah during the Early Jurassic Period about 200 million years ago, adjusted its stance, stood and walked away, that dinosaur’s behavior was recorded in the sediment beneath it. Similarly, when <a href="https://doi.org/10.1371/journal.pone.0010420">a fish swam along a lake bottom</a> in modern-day Wyoming more than 50 million years ago, it left not only trails from its fins, but also impressions from its mouth along the lake bottom while feeding. And <a href="https://theconversation.com/fossil-footprints-the-fascinating-story-behind-the-longest-known-prehistoric-journey-147520">human footprints from about 12,000 years ago</a> in modern-day New Mexico told of a young adult carrying a child across a foot path shared with mammoths and ground sloths. </p>
<p>Trace fossils, unlike shells and bones, provide snapshots – or even short documentary films – of animals living in their original environments.</p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p>
<h2>The Bahamas burrow</h2>
<p>Even though we found no body parts or eggs, there is ample evidence the structure we discovered in the Bahamas was an iguana burrow. The wind-blown layers in the former sand dune were clearly interrupted and mixed, showing the structure was made while the sand was still soft. It matches the width, depth and shape of <a href="https://www.elsevier.com/books/cyclura/lemm/978-1-4377-3516-1">modern iguana nesting burrows</a>. And nearby, <a href="https://scholar.google.com/citations?hl=en&user=7rgTfvkAAAAJ">one of us</a> (Melissa) found a fossilized land-crab burrow, insect burrows and root traces preserved in the outcrop, showing it was indeed an inland dune – exactly where an iguana would make a nest.</p>
<figure class="align-center ">
<img alt="A photo of the fossil, with a drawing superimposed on top outlining the different layers." src="https://images.theconversation.com/files/373425/original/file-20201207-21-rm7nj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373425/original/file-20201207-21-rm7nj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=508&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373425/original/file-20201207-21-rm7nj2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=508&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373425/original/file-20201207-21-rm7nj2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=508&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373425/original/file-20201207-21-rm7nj2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=638&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373425/original/file-20201207-21-rm7nj2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=638&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373425/original/file-20201207-21-rm7nj2.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=638&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The burrow deconstructed into its behavioral parts. NC? is a trace of the possible nest chamber, CZ (1-6) shows the compaction zones, where the mother iguana packed sand behind her on her way out, and the arrow shows her overall direction of movement while exiting.</span>
<span class="attribution"><span class="source">Anthony J. Martin</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The most convincing clue, however, is the series of compacted sand layers inside the structure. These are the places where the expectant mother packed sand with her legs and head on her way out in order to conceal her eggs and hatchlings from predators. </p>
<p>Interestingly, we did not find any evidence that the hatchlings dug their way out, through the layers, to the surface – as iguana hatchlings do. This indicates a failed nest. Although hatching success in modern iguanas is normally high, nest failures happen, and <a href="https://doi.org/10.1655/0733-1347(2004)018%5B0001:TNEOTA%5D2.0.CO;2">are most likely when soil moisture is too high</a>, such as after a heavy rain.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373113/original/file-20201204-15-hmlto3.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An iguana stands on a rock surface." src="https://images.theconversation.com/files/373113/original/file-20201204-15-hmlto3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373113/original/file-20201204-15-hmlto3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373113/original/file-20201204-15-hmlto3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373113/original/file-20201204-15-hmlto3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373113/original/file-20201204-15-hmlto3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373113/original/file-20201204-15-hmlto3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373113/original/file-20201204-15-hmlto3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The endangered San Salvador Island rock iguana (<em>Cyclura riyeli riyeli</em>).</span>
<span class="attribution"><span class="source">Anthony J. Martin</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Iguanas on San Salvador</h2>
<p>The oldest known iguana body fossils from San Salvador date from less than 12,000 years ago. The discovery of this burrow, from 115,000 years ago, greatly extends the natural history of iguanas in this location.</p>
<p>The iguanas that live on San Salvador Island today are among the rarest lizard species in the world – the San Salvador Island rock iguana (<em>Cyclura riyeli riyeli</em>). This species and others were common throughout the Bahamas before 1492, when <a href="http://www.ircf.org/journal/wp-content/uploads/2017/01/Iguana11_4_web.pdf#page=27">Europeans introduced rats, pigs and other invasive species</a> that preyed on eggs and iguanas of all ages. Now, fewer than 500 individuals persist on isolated cays offshore from the main part of San Salvador.</p>
<p>We hope our study generates awareness and appreciation of Bahamian iguanas and their long history in this area. We also hope it inspires their continued protection.</p><img src="https://counter.theconversation.com/content/151270/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A trace fossil of an iguana burrow was discovered on San Salvador Island in the Bahamas. Estimated to be 115,000 years old, it is the first known fossil of its kind.Anthony J. Martin, Professor of Practice, Emory UniversityMelissa Hage, Assistant Professor of Environmental Science, Emory UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1366732020-04-28T12:10:37Z2020-04-28T12:10:37ZScientists at work: Uncovering the mystery of when and where sharks give birth<figure><img src="https://images.theconversation.com/files/330807/original/file-20200427-145566-12cpxhm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Using new technology to answer questions about shark reproduction.</span> <span class="attribution"><a class="source" href="http://www.blueelementsimaging.com">Tanya Houppermans</a></span></figcaption></figure><p>If you have a toddler, or if you encountered one in the last year, you’ve almost certainly experienced the <a href="https://www.youtube.com/watch?v=XqZsoesa55w">“Baby Shark” song</a>. Somehow, every kid seems to know this song, but scientists actually know very little about <a href="https://www.nationalgeographic.com/magazine/2016/07/great-white-shark-research-population-behavior/">where and when sharks give birth</a>. The origins of these famous baby sharks are still largely a mystery.</p>
<p>Many of the large iconic shark species – like great whites, hammerheads, blue sharks and tiger sharks – cross hundreds or thousands of miles of ocean every year. Because they’re so wide-ranging, much of sharks’ lives, including their reproductive habits, remains a secret. Scientists have struggled to figure out precisely where and how often sharks mate, the length of their gestation, and many aspects of the birthing process. </p>
<p><a href="https://hannahverkamp.wixsite.com/profile">I am a Ph.D. student</a> studying shark ecology and reproduction and am on a team of researchers hoping to answer two important questions: Where and when do sharks give birth?</p>
<h2>In need of innovation</h2>
<p>Until very recently, the technology to answer these questions did not exist. But marine biologist James Sulikowski, a professor at Arizona State University and my research mentor, changed that. He developed a new satellite tag called the Birth-Tag with the help of the technology company <a href="https://www.lotek.com">Lotek Wireless</a>. He has no stake in the company. Using this new satellite tag, our team is working to uncover where and when tiger sharks give birth and is demonstrating a proof of concept for how scientists can do the same for other large shark species. </p>
<p>The Birth-Tag is a small, egg-shaped device that we insert into the uterus of a pregnant shark where it will remain dormant and hidden among the fetal sharks throughout pregnancy. This kind of tag has never before been used on sharks, but <a href="https://doi.org/10.1186/s40317-019-0184-4">similar implanted tags</a> have been used to figure out the birthing locations of terrestrial mammals, such as deer, for decades with great success. When a tagged mother shark gives birth, the tag will be expelled alongside the babies and float to the sea surface. Once it senses dry air, the tag transmits its location to a passing satellite, which then sends that location and time of transmission back to our lab. As soon as we download this information, we know where and when that shark gave birth.</p>
<p>After years of fine-tuning this new technology, we launched the first phase of the study in December of 2019 and began deploying the tags. Once the study was approved by the Institutional Animal Care and Use Committees at both Arizona State University and the University of Miami, as well as the Bahamian government, we set out to find some tiger sharks. To do this, our team of researchers from the <a href="https://sites.google.com/view/sulikowskilab/home">Sulikowski Shark and Fish Conservation Lab</a> and the <a href="https://sharkresearch.rsmas.miami.edu">Shark Research and Conservation Program</a> at the University of Miami led by marine biologist Neil Hammerschlag, traveled to the crystal-clear waters of Tiger Beach off Grand Bahama Island to tag tiger sharks.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330802/original/file-20200427-145525-180kd6g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330802/original/file-20200427-145525-180kd6g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330802/original/file-20200427-145525-180kd6g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330802/original/file-20200427-145525-180kd6g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330802/original/file-20200427-145525-180kd6g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330802/original/file-20200427-145525-180kd6g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330802/original/file-20200427-145525-180kd6g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330802/original/file-20200427-145525-180kd6g.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"></a>
<figcaption>
<span class="caption">Tiger sharks are large and powerful predators. Getting close enough for a check-up is not easy.</span>
<span class="attribution"><a class="source" href="https://www.blueelementsimaging.com/">Tanya Houppermans</a></span>
</figcaption>
</figure>
<h2>Up close with an apex predator</h2>
<p>Tiger Beach is a <a href="https://doi.org/10.3354/ab00648">hot spot for female tiger sharks</a> of many different life stages, including large pregnant individuals. These pregnant females may be aggregating in the warm, calm waters of Tiger Beach to take refuge and speed up their gestation.</p>
<p>The high number of pregnant sharks in this small area makes finding one much easier, but actually catching and bringing a 10-foot-plus shark to the boat is no easy task. We fish for the sharks <a href="https://www.semanticscholar.org/paper/Integrating-Physiological-and-Reflex-Biomarkers-of-Jerome/01db87057ab3142d134095d3340345d971277a1c/figure/1">using drumlines</a>, and it can take several hours to safely catch, pull in by hand, and secure one of these powerful creatures next to the boat.</p>
<p>Once we catch a female tiger shark, we first take several length and girth measurements to get an idea of her general health and to see if she is sexually mature. Then we check for bite marks, which are evidence of a recent mating event.</p>
<p>After we collect this baseline information, we rotate her upside down to coax her into a trance-like state called <a href="https://www.sharktrust.org/tonic-immobility">tonic immobility</a>. Tonic immobility is a natural reflex in many sharks that induces a state of physical inactivity. This keeps the powerful shark calm and still for the most exciting part of the workup, the part where my experience comes into play: the pregnancy check.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330800/original/file-20200427-145513-1m8s6jo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330800/original/file-20200427-145513-1m8s6jo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330800/original/file-20200427-145513-1m8s6jo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330800/original/file-20200427-145513-1m8s6jo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330800/original/file-20200427-145513-1m8s6jo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330800/original/file-20200427-145513-1m8s6jo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330800/original/file-20200427-145513-1m8s6jo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330800/original/file-20200427-145513-1m8s6jo.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">A not-so-routine ultrasound.</span>
<span class="attribution"><a class="source" href="https://www.blueelementsimaging.com/">Tanya Houppermans</a></span>
</figcaption>
</figure>
<h2>Expecting</h2>
<p>Just like the ultrasounds used on humans, we use a mobile ultrasound machine to figure out if a shark is expecting. I put on a pair of goggles that allow me to see everything the ultrasound sees, lean over the side of the boat, and place the probe onto the upside down shark’s abdomen. The image is usually fuzzy at first as water splashes over the shark and up onto the boat. The team holds the shark still as I slowly maneuver the probe along her belly. Then, if she’s pregnant, something magical happens.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/330801/original/file-20200427-145513-nuf0v8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330801/original/file-20200427-145513-nuf0v8.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/330801/original/file-20200427-145513-nuf0v8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330801/original/file-20200427-145513-nuf0v8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330801/original/file-20200427-145513-nuf0v8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330801/original/file-20200427-145513-nuf0v8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330801/original/file-20200427-145513-nuf0v8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330801/original/file-20200427-145513-nuf0v8.png?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">A happy healthy baby is a welcome sight for any mother.</span>
<span class="attribution"><a class="source" href="https://newcollege.asu.edu/james-sulikowski">James Sulikowski</a></span>
</figcaption>
</figure>
<p>Wriggling baby tiger sharks, up to 40 of them packed tightly together inside their mother’s womb, appear in front of my eyes. The image also appears on a screen held by another team member on the boat, and everyone cheers as they gather around to take a peek into the secret world of unborn sharks. We spy on them as they pump fluid through their still-developing gills, and we watch in awe as they wiggle around, blissfully unaware that anything extraordinary is happening outside in the world. Once we have enough data on the approximate size of the offspring – which gives us an idea of how far along the pregnancy is – it’s time to tag the mama shark.</p>
<p>As I hold the probe as still as possible to keep a visual of the shark’s internal anatomy, Dr. Sulikowski takes the Birth-Tag and uses a custom-designed applicator to carefully insert it into the uterus through the urogenital opening. No surgery required, the tagging procedure is complete in a matter of minutes. Once the tag is inside the uterus, we rotate the shark upright to wake her and release her back to the open ocean. I am filled with hope as I watch her swim gracefully away to continue her pregnancy, with a stow-away Birth-Tag hidden among her unborn offspring.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330813/original/file-20200427-145530-1paqeo1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330813/original/file-20200427-145530-1paqeo1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330813/original/file-20200427-145530-1paqeo1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330813/original/file-20200427-145530-1paqeo1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330813/original/file-20200427-145530-1paqeo1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330813/original/file-20200427-145530-1paqeo1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330813/original/file-20200427-145530-1paqeo1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330813/original/file-20200427-145530-1paqeo1.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">These apex predatory sharks are important to ecosystems around the world.</span>
<span class="attribution"><a class="source" href="https://www.blueelementsimaging.com/">Tanya Houppermans</a></span>
</figcaption>
</figure>
<h2>Solving the mystery</h2>
<p>Last December, we deployed the first Birth-Tags on three pregnant tiger sharks. For tiger sharks, pregnancy is thought to last <a href="http://sedarweb.org/docs/wsupp/S21_RD07_AQUA15(4)_Cycles2.pdf">12-16 months</a>, but researchers have little in the way of hard data. Since these tagged sharks ranged from recently mated to mid-gestation, an added bonus of this study is that it might help refine estimates of the length of pregnancy for this species.</p>
<p>Although we work in The Bahamas, a <a href="https://www.epicdiving.com/bahamas-shark-sanctuary-conservation/">shark sanctuary</a> where it is illegal to kill sharks, tiger sharks <a href="https://dx.doi.org/10.1038%2Fsrep11202">migrate extensively</a>. As such, each tagged shark will likely spend time outside of The Bahamas in unprotected waters where she will have to navigate carefully to avoid interaction with fishing gear. Tiger sharks are considered <a href="https://www.iucnredlist.org/species/39378/2913541">near threatened</a> by the International Union for Conservation of Nature and their populations are currently in decline. The data we gain from this first round of tags will give us and policymakers information that could inform future protections for this species.</p>
<p>We are currently waiting to receive a notification from our online <a href="https://www.argos-system.org/argos/who-we-are/international-cooperation/">ARGOS satellite system</a> that will alert us that one of our sharks has given birth. When that happens, we will be the first in the world to know, in close to real time, where and when tiger sharks give birth.</p>
<p>Many species of shark are <a href="https://elifesciences.org/articles/00590">threatened with extinction</a>, and understanding their reproductive cycles is key to the effective conservation of these ecologically important and beautiful creatures. Using the Birth-Tag, we are at the cusp of unlocking this information about tiger sharks and will hopefully show that this can be done for many more species. </p>
<p>We are planning future expeditions to deploy many more Birth-Tags, but for now, we’ll just have to keep singing the “Baby Shark” song as we patiently wait for our first glimpse into the private lives of these incredible creatures.</p>
<p><em>This story has been updated to remove a photo of the Birth-Tag.</em></p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/136673/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hannah Verkamp works for Arizona State University as a Research Associate in the Sulikowski Shark and Fish Conservation Lab.
The research is funded by the Herbert W. Hoover Foundation. </span></em></p>Researchers are using a newly developed satellite tag to study previously unknown aspects of tiger shark reproduction. This approach could be used on other difficult-to-study shark species.Hannah Verkamp, PhD Student in Marine Biology, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1234932019-09-18T10:24:31Z2019-09-18T10:24:31ZHurricane Dorian was also a catastrophe for the Bahamas’ unique birds<figure><img src="https://images.theconversation.com/files/292687/original/file-20190916-19076-nwi96j.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4321%2C2753&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists are worried about the Abaco, a subspecies of parrot found found only in the Bahamas.</span> <span class="attribution"><span class="source">Henner Damke / Shutterstock</span></span></figcaption></figure><p>Hurricane Dorian was the <a href="https://news.sky.com/story/first-contact-sky-news-reaches-forgotten-hurricane-dorian-survivors-11806675">second most powerful Atlantic hurricane on record</a> and the fifth to reach the highest hurricane category (five) in the past four years. After it first made landfall, it hovered over the northern Bahamas for more than 50 hours.</p>
<p>The human death toll is currently around 50 but <a href="https://www.buzzfeednews.com/article/briannasacks/cadaver-dogs-hurricane-dorian-victims-search">more than 1,000 people are still missing</a> and at least <a href="https://www.youtube.com/watch?v=3ICzMoJ0bbk">70,000</a> have been left homeless. Many residents have lost everything, including their tourism industry, and are in desperate need of <a href="https://www.npr.org/2019/09/11/759780932/how-to-help-hurricane-dorian-survivors-in-the-bahamas">humanitarian assistance</a>. </p>
<p>At a time of such immense human tragedy, it may seem too soon to mourn the loss of wildlife. But, as a conservation biologist who specialises in island ecology, I am also worried about the Bahamas’s unique birdlife – several species may have have been severely harmed or even lost, literally overnight. </p>
<p>Just this time last year, my UEA master’s students, Matthew Gardner and David Pereira, spent several months researching birds on Grand Bahama island and were able to announce the <a href="https://www.uea.ac.uk/about/-/bird-feared-extinct-rediscovered-in-the-bahamas">rediscovery of a species</a> that had not been seen since Hurricane Matthew in 2016: the Bahama nuthatch (<em>Sitta insularis</em>). One of several bird species endemic to these islands – that is, it lives nowhere else – the nuthatch is a tiny bird that nests in tree cavities. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/0eiy6yWxeqA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Possibly the last ever footage of a living Bahama nuthatch (Credit: UEA)</span></figcaption>
</figure>
<p>The nuthatch was <a href="https://medicine.llu.edu/sites/medicine.llu.edu/files/docs/grand-bahamas-brown-headed-nuthatch-a-distinct-and-endangered-species.pdf">already suffering</a> from habitat fragmentation, invasive predators such as snakes and cats and the local extinction of a native woodpecker species, the West Indian woodpecker, in the 1990s. This woodpecker had previously created tree holes subsequently used by the nuthatch, which likes to nest in small cavities.</p>
<p>Matthew, David and others from the University of the Bahamas played a recording of the nuthatch’s call in order to attract and observe it – they found the bird was alive after all. However, we feared numbers may be as low as just one or two individuals. </p>
<p>Sadly, the species is unlikely to have survived Dorian. </p>
<p>In fact, Dorian may have not only sealed the fate of the nuthatch but also severely impacted other birds endemic to these islands, particularly the Bahama warbler and the Abaco parrot. Also known as the <a href="https://www.friendsoftheenvironment.org/abaco/bahamas-parrot/">Bahama Amazon parrot</a>, this subspecies uniquely nests in limestone cavities on the ground which are likely to have been flooded by the storm surge.</p>
<p>Other birds we’re worried about include the Bahama yellow throat, Olive-capped warbler, the Bahama woodstar hummingbird and the Bahama swallow. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/292861/original/file-20190917-19068-kptymy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/292861/original/file-20190917-19068-kptymy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292861/original/file-20190917-19068-kptymy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=374&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292861/original/file-20190917-19068-kptymy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=374&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292861/original/file-20190917-19068-kptymy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=374&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292861/original/file-20190917-19068-kptymy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=469&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292861/original/file-20190917-19068-kptymy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=469&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292861/original/file-20190917-19068-kptymy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=469&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A female Bahama woodstar. These small hummingbirds weigh just two or three grams.</span>
<span class="attribution"><span class="source">Rafael Vila / flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Nowhere to hide</h2>
<p>Scientists don’t know exactly how different birds try to escape the strong winds and heavy rainfall associated with hurricanes. It’s not the easiest thing to study in nature, for obvious reasons. We do know that previous storms have blown species like the swallow and woodstar as far as Florida or even <a href="https://www.pennlive.com/wildaboutpa/2013/05/harrisburg_bird_bander_extends.html">Pennsylvania</a>, so it’s possible that some individuals particularly the swallows may have escaped by flying to other islands ahead of the hurricane. But for most birds, the best chance of survival would have been to seek shelter in the pine forest.</p>
<p>Once covering much of the islands, this native ecosystem had evolved alongside Atlantic hurricanes and should in theory provide native birds with protection from a major storm. However, throughout the 20th century much of the Bahama pine forest was lost to industrial logging or urban development, and what remains is <a href="https://www.audubon.org/conservation/international/ecotourism/bahamas">highly fragmented</a>. More recently, major hurricanes have caused direct wind damage and storm surges that have sent salt water far inland, killing trees. </p>
<p>For the birds, all this is a disaster. Not only has much of their native habitat disappeared, but going down from trees to hide in ground cover would not be an option if the ground was flooded by the torrential rain.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/292684/original/file-20190916-19049-14h9jp8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/292684/original/file-20190916-19049-14h9jp8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292684/original/file-20190916-19049-14h9jp8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292684/original/file-20190916-19049-14h9jp8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292684/original/file-20190916-19049-14h9jp8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292684/original/file-20190916-19049-14h9jp8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292684/original/file-20190916-19049-14h9jp8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292684/original/file-20190916-19049-14h9jp8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Bahama warbler.</span>
<span class="attribution"><span class="source">David Pereira / UEA</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>All this is compounded by a further environmental impact of Dorian: an oil spill from a large storage facility on Grand Bahama island which is reported to have been holding <a href="https://www.npr.org/2019/09/06/758358451/oil-seen-leaking-from-hurricane-hit-facility-on-grand-bahama-island">1.8m barrels</a> at the time. That, along with the fact a hurricane usually dumps lots of plastic into the ocean, means even surviving birds may struggle to find feed and fresh water. </p>
<h2>Island species are under threat</h2>
<p>Globally, as many as <a href="http://datazone.birdlife.org/sowb/casestudy/we-have-lost-over-150-bird-species-since-1500">182 bird species</a> are thought to have become extinct over the past five centuries. Of these, an astonishing 92% have been island species. We can blame most of these historical extinctions on habitat destruction and introduced species such as rats and cats. But in future, endangered birds on oceanic islands must also contend with stronger and more frequent hurricanes driven by climate change.</p>
<p>The lesson from Dorian is that we must conserve and restore as much native plant habitat as possible. On islands like the Bahamas, native plants often themselves now endangered, provide crucial habitats for threatened species, and conserve freshwater and soils thus protecting against erosion and landslides.</p>
<p>The Caribbean has a wealth of endemic plants and animals, many of which are threatened by human activities. It has therefore been recognised as a global <a href="https://ec.europa.eu/environment/nature/biodiversity/best/regions/caribbean_en.htm">biodiversity hotspot</a>. </p>
<p>It’s hard to say for certain what climate change and more frequent strong hurricanes will mean for this biodiversity, but the avifauna and habitat surveys conducted by Matthew and David in 2018 provide a crucial baseline for us to determine the ecological impact of Dorian on the Bahamas. What has just happened may represent the irreplaceable loss of a small but nonetheless precious part of the planet’s biological heritage.</p><img src="https://counter.theconversation.com/content/123493/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The UEA research on Grand Bahama was done in collaboration with the Bahamas National Trust and Birdlife International.</span></em></p>What has just happened may represent the irreplaceable loss of a small but nonetheless precious part of the planet’s biological heritage.Diana Bell, Professor of Conservation Biology, University of East AngliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1231332019-09-10T11:56:25Z2019-09-10T11:56:25Z4 tips for selecting charities after disasters like Hurricane Dorian<figure><img src="https://images.theconversation.com/files/291349/original/file-20190906-175696-1kw7hc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">After hurricanes, there are always people who could use a hand.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Tropical-Weather/0f4c7e9a69f942c38c0ddcf53a19f57f/1/0">AP Photo /Jeffrey Collins</a></span></figcaption></figure><p>Hurricane Dorian’s destruction in <a href="https://www.reuters.com/article/us-storm-dorian/staggering-death-toll-feared-in-bahamas-after-dorians-destruction-idUSKCN1VS0A0">the Bahamas</a>, <a href="https://www.apnews.com/d2ae083dec3b485888e386f6660538bd">North Carolina</a> and up the Atlantic coast provides a terrible reminder of how these storms can upend lives and destroy homes. As with <a href="https://theconversation.com/american-generosity-after-disasters-4-questions-answered-83277">previous disasters</a>, millions of Americans are trying to figure out the best way to use their money to help people recover.</p>
<p>As a scholar who has <a href="https://scholar.google.com/citations?user=VYsdAEIAAAAJ&hl=en">studied philanthropy after disasters</a>, I’m hearing from friends and colleagues that the growing number of charities responding to these emergencies is making them unsure about which one to support. If you are feeling the same way, here’s my advice.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/UysJARy1u2I?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Stevie Wonder performs the Bill Withers song ‘Lean on Me’ during the ‘Hand in Hand’ telethon to benefit victims of Hurricane Harvey and Hurricane Irma in 2017.</span></figcaption>
</figure>
<h2>1. Decide what matters most to you</h2>
<p>Giving is a personal decision motivated by personal values and passions. So, before you search for the right charity, clarify a few things in your own mind.</p>
<p>Do you prefer to support local, national or global organizations? Would you rather give directly to individuals in need? </p>
<p>National and international organizations have specialized expertise. Local groups know the territory. </p>
<p>The Red Cross, the biggest disaster relief nonprofit, operates everywhere. It has the ability to be on the ground, making a difference right away. But <a href="https://theconversation.com/why-hurricane-harvey-donors-shouldnt-boycott-the-red-cross-83289">debates crop up from time to time</a> over its effectiveness due to <a href="https://www.cbsnews.com/news/red-cross-faces-criticism-over-hurricane-harvey-relief-distribution/">concerns over how it dealt with</a> some previous disasters.</p>
<p>National organizations, such as <a href="https://teamrubiconusa.org/hurricane-dorian-relief/?gclid=EAIaIQobChMI9-7chMzC5AIVVwOGCh0ZgQ6wEAAYASAAEgKe1vD_BwE">Team Rubicon</a> and <a href="https://give.helpsalvationarmy.org/give/166081/#!/donation/checkout">the Salvation Army</a>, as well as
<a href="https://www.gbdisasterrelief.org/">the Grand Bahama Disaster Relief Foundation</a>, a local organization, and <a href="https://www.gofundme.com/">GoFundMe</a>, a platform for giving directly to people in need, are all responding to the emergencies created by Hurricane Dorian.</p>
<p>Also consider timing.</p>
<p>Do you care more about helping people immediately or over the long term? Hurricane survivors need <a href="https://www.nytimes.com/2019/09/08/world/americas/bahamas-dead-dorian.html?action=click&module=Top%20Stories&pgtype=Homepage">food, shelter and other basics right away</a>. But as the aftermath of <a href="https://www.theguardian.com/us-news/2017/aug/29/houston-texas-harvey-recovery-efforts">Hurricane Harvey in 2017</a> and the 2012 hurricane widely known as Superstorm Sandy made clear, relief efforts may take <a href="https://theconversation.com/it-takes-years-to-fully-recover-from-big-storms-like-sandy-118381">many years</a>. </p>
<p>Once you set these priorities, seek groups that do the kind of work you care about most. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/291560/original/file-20190909-109927-1qck3qv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/291560/original/file-20190909-109927-1qck3qv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/291560/original/file-20190909-109927-1qck3qv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291560/original/file-20190909-109927-1qck3qv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291560/original/file-20190909-109927-1qck3qv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291560/original/file-20190909-109927-1qck3qv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291560/original/file-20190909-109927-1qck3qv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291560/original/file-20190909-109927-1qck3qv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hurricane Dorian destroyed thousands of homes on Great Abaco, an island in the Bahamas.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Bahamas-Tropical-Weather/b1dc4d6a9f064c4fb789686f476c13bc/20/0">AP Photo/Gonzalo Gaudenzi</a></span>
</figcaption>
</figure>
<h2>2. Consider several options</h2>
<p>No matter where emergencies arise, international organizations such as <a href="https://www.redcross.org/ns/apology/disaster_homepage.html">Red Cross</a>, the <a href="http://www.salvationarmyusa.org/">Salvation Army</a>, <a href="http://www.americares.org/en/what-we-do/emergency-programs/">Americares</a> and the United Nations Children’s Fund (<a href="https://www.unicefusa.org/mission/emergencies">UNICEF</a>) respond and provide relief.</p>
<p>But they aren’t your only options. After an earthquake, hurricane or other tragedy, many established charities adapt their services to respond to the needs that emerge, as I learned in <a href="http://journals.sagepub.com/doi/abs/10.1177/0275074009336205">research I conducted</a> about how nonprofits responded to the 9/11 terrorist attacks.</p>
<p>Many media outlets and specialty websites compile lists with good options. Following Hurricane Dorian, examples include <a href="https://beta.washingtonpost.com/world/the_americas/hurricane-dorian-aid-how-to-donate-to-rescue-relief-and-recovery-in-the-bahamas/2019/09/05/903ba688-cff4-11e9-a620-0a91656d7db6_story.html">The Washington Post</a>, <a href="https://www.usatoday.com/story/news/2019/09/03/hurricane-dorian-destroyed-bahamas-heres-how-you-can-help/2194099001/">USA Today</a>, <a href="https://www.pbs.org/newshour/world/how-to-help-those-affected-by-hurricane-dorian">PBS NewsHour</a> and <a href="https://www.charitynavigator.org/index.cfm?bay=content.view&cpid=7485">Charity Navigator</a>.</p>
<p>After you find the groups aligned with your interests, visit their websites. Read their mission statements and look for descriptions of how they’re helping. </p>
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<h2>3. Focus on results</h2>
<p>Knowing what matters to you and what your giving options are a good start, but not enough. You also need to make sure a charity is likely to make a difference with your money. </p>
<p>Most people donate <a href="http://disasterphilanthropy.org/notable-research/philanthropic-grantmaking-disasters-lessons-learned-conrad-n-hilton-foundation/">in the first two months</a> following a disaster. That means that when you research your giving options, the best information you’re likely to find is what an organization plans to do or is doing right now.</p>
<p>That’s useful, but it doesn’t tell you whether they’ll do a good job. </p>
<p>Given that challenge, what kind of information can help you make a good decision? Results from past work, whether in disaster response or something else, can at least tell you something about reliability. Any nonprofit asking for your money after a hurricane or earthquake – or any time, for that matter – should make it easy to find information about results on their website. </p>
<p>Look for answers to these questions. After the last disaster: </p>
<ul>
<li>Did they spend all the money they received? </li>
<li>How did they spend it?</li>
<li>Did the money make a meaningful difference in addressing people’s needs? </li>
</ul>
<p>The <a href="https://www.unitedway.org/">United Way</a>, which often plays a major role in disaster relief, distributes the money it raises to community groups that help those affected. After major disasters, such as <a href="https://www.unitedway.org/recovery/hurricane-harvey">Hurricane Harvey</a>, it releases updates about how it spent donors’ dollars. The <a href="https://www.robinhood.org/programs/special-initiatives/relief/hurricane-sandy/grants/">Robin Hood Foundation</a> set another good example when it reported on its work following Superstorm Sandy. </p>
<p>Details about results can be hard to find on charity websites. But many organizations providing disaster relief do provide them.</p>
<p>For instance, the Red Cross website includes <a href="http://www.redcross.org/about-us/news-and-events/publications">a long list of publications</a> regarding its responses to disasters, and the Salvation Army has posted videos, with more limited information, that describe its efforts in response to <a href="http://newyork.salvationarmy.org/ways-we-help/disaster-relief/disaster-services/">Hurricane Katrina</a> and the <a href="https://www.youtube.com/watch?v=WUx3cpglYeU&t=4s">Haiti earthquake</a>.</p>
<p><a href="http://www.guidestar.org/Home.aspx">GuideStar</a> is a good information source because it enables charities to upload results-related information on its site. For example, the Humane Society of the United States provides results information on <a href="https://www.guidestar.org/profile/53-0225390">its GuideStar page</a> and also describes <a href="http://www.humanesociety.org/about/hsus-transformational-change.html?credit=web_id93480558">accomplishments</a> on its website. </p>
<h2>4. Watch for red flags</h2>
<p>Finally, consult charity rating sites.</p>
<p>These sites score nonprofits by applying their own criteria, making comparison easy. What they rate varies but usually includes financial performance, management practices and transparency. <a href="https://www.charitynavigator.org/index.cfm?bay=content.view&cpid=1284">Charity Navigator</a>, the <a href="http://www.give.org/">Better Business Bureau/Wise Giving Alliance</a> and <a href="https://www.charitywatch.org/home">Charity Watch</a> are among the best-known.</p>
<p>Before giving to a nonprofit, ensure that it has a high score with one or more of those groups and see if there are reasons for concern. One good resource is Charity Navigator’s frequently updated <a href="https://www.charitynavigator.org/index.cfm?bay=search.cnadvisories">donor advisory</a> list. It catalogs everything from reports of <a href="https://www.charitynavigator.org/index.cfm?bay=search.summary&orgid=17350">embezzled funds</a> and <a href="https://www.charitynavigator.org/index.cfm?bay=search.summary&orgid=16832">fraud</a> to <a href="https://www.charitynavigator.org/index.cfm?bay=search.summary&orgid=9485">unclear financial reports</a>. </p>
<p>Donate what you can spare after disasters. But, as the old adage suggests, good intentions don’t always yield good results. Doing a little research and following these guidelines can help you feel more confident about your donations and the difference they will make.</p>
<p><em>This article contains information in an earlier article The Conversation US published on <a href="https://theconversation.com/how-to-select-a-disaster-relief-charity-83928">Sept. 26, 2017</a></em></p>
<p>[ <em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/123133/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Campbell is a board member of the Conrad and Virginia Klee Foundation and Racker, a disability service organization based in Ithaca, New York. He has previously served on an advisory committee for Charity Navigator. </span></em></p>After a hurricane strikes or an earthquake makes shockwaves, try to support nonprofits that are clear about what they do and how they will spend your money.David Campbell, Associate Professor of Public Administration, Binghamton University, State University of New YorkLicensed as Creative Commons – attribution, no derivatives.