Larsen P.A.,Duke University |
Hayes C.E.,Duke University |
Wilkins M.A.,Duke University |
Sookhareea R.,National Parks and Conservation Service |
And 3 more authors.
Acta Chiropterologica | Year: 2014
The Mauritius flying fox Pteropus niger is distributed on the islands of Mauritius and La Réunion in the western Indian Ocean. Although recent studies have examined the phylogenetics and systematics of this genus, relatively few have assessed the population genetics of species distributed on oceanic islands and no study has focused on the demographics of P. niger. Here, we present mitochondrial DNA sequence data from 39 individuals of P. niger collected from four main colonies distributed throughout Mauritius. Our results indicate that the Mauritian population of P. niger is likely panmictic, with moderate to high levels of gene flow occurring among colonies distributed across the island. Collectively, our sequence data suggest moderate levels of genetic variation within the population. These findings will help to inform ongoing conservation and disease surveillance initiatives. © Museum and Institute of Zoology PAS. Source
Buckland S.,University of Bristol |
Buckland S.,University of Sheffield |
Cole N.C.,University of Bristol |
Groombridge J.J.,University of Kent |
And 5 more authors.
PLoS ONE | Year: 2014
Genetic structure can be a consequence of recent population fragmentation and isolation, or a remnant of historical localised adaptation. This poses a challenge for conservationists since misinterpreting patterns of genetic structure may lead to inappropriate management. Of 17 species of reptile originally found in Mauritius, only five survive on the main island. One of these, Phelsuma guimbeaui (lowland forest day gecko), is now restricted to 30 small isolated subpopulations following severe forest fragmentation and isolation due to human colonisation. We used 20 microsatellites in ten subpopulations and two mitochondrial DNA (mtDNA) markers in 13 subpopulations to: (i) assess genetic diversity, population structure and genetic differentiation of subpopulations; (ii) estimate effective population sizes and migration rates of subpopulations; and (iii) examine the phylogenetic relationships of haplotypes found in different subpopulations. Microsatellite data revealed significant population structure with high levels of genetic diversity and isolation by distance, substantial genetic differentiation and no migration between most subpopulations. MtDNA, however, showed no evidence of population structure, indicating that there was once a genetically panmictic population. Effective population sizes of ten subpopulations, based on microsatellite markers, were small, ranging from 44 to 167. Simulations suggested that the chance of survival and allelic diversity of some subpopulations will decrease dramatically over the next 50 years if no migration occurs. Our DNA-based evidence reveals an urgent need for a management plan for the conservation of P. guimbeaui. We identified 18 threatened and 12 viable subpopulations and discuss a range of management options that include translocation of threatened subpopulations to retain maximum allelic diversity, and habitat restoration and assisted migration to decrease genetic erosion and inbreeding for the viable subpopulations. © 2014 Buckland et al. Source
In a move that has outraged conservationists, the government of the Indian ocean nation of Mauritius is planning to kill off nearly 20,000 Mauritius fruit bats, a protected species that is found only on the island. Mauritian fruit growers are claiming that the bat is responsible for significant agricultural losses, but scientists say that’s dubious — and that the planned number of bats killed could imperil the entire species. It wouldn’t be the first time human actions have threatened a Mauritian animal. Over the past few centuries, several species have disappeared from the island, the most famous of these being the Dodo, which was hunted to extinction by the beginning of the 18th century. Since then, the Dodo has become a poster child for the conservation movement, and a grim warning to the world — and to the island of Mauritius, in particular — of the dangers of the unsustainable killing of wildlife. The Mauritius fruit bat, sometimes referred to as the Mauritius flying fox, is a fruit-eating bat with leathery wings and, of course, nocturnal habits. It makes an impressive figure, with its fox-like features, golden-brown fur and a wingspan that can exceed two feet. The species has faced many threats over the past few decades from hunting, habitat loss and the effects of cyclones, which can have devastating impacts on the island and its inhabitants. The species was considered critically endangered in the 1970s and 1980s, when it began a long recovery. It was listed as endangered by the International Union for the Conservation of Nature (IUCN) in 2008 and downlisted to “vulnerable” in 2013 after showing some improvement. It’s still considered a protected species in Mauritius. In addition to its precarious conservation history, the bat has a complicated relationship with the people of Mauritius. Fruit growers on the island have argued for years that the bats are highly destructive to their crops and should be viewed as pests. In response, the government of Mauritius initiated a small-scale cull in 2006, which is believed to have only led to the deaths of a few thousand of the bats, at least partly thanks to its protected status, which prohibits shooting them after dark. And in 2009 the government began subsidizing the cost of protective nets that could be placed around trees in order to keep out fruit-eating animals. Despite these measures, fruit growers have reported continued damage to their produce — and on Oct. 6, at the Sixth Assembly of the Mauritian National Parliament, Minister of Agro-Industry and Food Security Mahen Kumar Seeruttun announced plans for another controlled cull, this time with aims to eliminate 18,000 bats. During his announcement, the minister cited reports from the Food and Agricultural Research and Extension Institute, which claim that bat-related damage “recorded for the year 2014 for litchi reaches as high as 73 percent in orchards whilst damage caused to mango is estimated up to 42 percent in backyards,” he said, according to a transcript of the meeting. “In view of the huge economic losses being incurred by fruit growers, bold and urgent action is required to reduce the bat population and hence reduce the damages caused to fruits,” Seeruttun said during the assembly. He said the government expects to cull about 20 percent of the fruit bat population starting this month, and with current government estimates placing the population at about 90,000 strong, this would amount to killing 18,000 bats. While the culling has not yet begun, according to Vincent Florens, an associate professor of ecology at the University of Mauritius, the proposal calls for the Mauritius Special Mobile Force, the government’s main security force, to carry it out by shooting the bats. Officials from the Ministry of Agro-Industry and Food Security, including Seeruttun, did not respond to repeated requests for comment. Conservationists are concerned that the island has overestimated how many of the bats it still has and how much damage they are causing to fruit trees on the island. The National Parks and Conservation Service concluded that the island had 90,000 bats left by counting bats in different roosts at different times. But that is problematic because Mauritius fruit bats often switch roosts if they’re disturbed in the middle of the day, Florens said. This means that there’s a high possibility many of the bats were counted multiple times in different places, he said. A more accurate population estimate would be closer to 50,000, Florens said, meaning a cull of 18,000 bats would take out about 36 percent of the population. And this could be disastrous for the species. The “implementation of a cull will very likely result in an up-listing of the species from Vulnerable to Endangered or Critically Endangered on the IUCN Red List, which will damage the reputation of Mauritius as a world leader on conservation,” IUCN said in a recent statement. The Mauritian Wildlife Foundation has also publicly opposed the cull, noting in a statement: “Currently the evidence we have does not support a cull.” The foundation also drew attention to several other ethical issues associated with the cull in its statement. For one thing, it noted, culls by shooting can result in bats being wounded and taking several days to die. Additionally, many Mauritius fruit bats are pregnant or raising babies during this time of year. This means that many babies could die if their mothers are killed — and it also means that a disproportionate number of female bats could be killed, as they’re likely to be slower and easier targets than the males this time of year, said Ryszard Oleksy, a postdoctoral researcher at the University of Bristol who’s currently involved in researching the bat’s impact on fruit trees in Mauritius. Oleksy said his research also indicates that culling the bats would be of little benefit to Mauritian fruit growers. Preliminary results indicate that bats are responsible for about 11 percent of damaged fruit on large mango trees and less than 3 percent of the damage on small trees, he said. Similarly, Oleksy said his research has so far suggested that bats account for less than 10 percent of the damage observed on litchi trees. He found that other animals, such as birds and rats, are also responsible for a significant amount of the damage caused to fruit trees. And Florens, the University of Mauritius professor, also noted that inefficient harvesting techniques, which allow a hefty amount of fruit to go bad before it’s collected, also account for a great deal of wasted fruit on the island, far more so than any damage caused by bats. The reasons for the discrepancy between Oleksy’s research and the government’s estimates of bat-caused damage are unclear. But Oleksy suggests that part of the reason bats get a disproportionate amount of the blame is because they feed at night and fruit growers are unable to observe them and make accurate estimates of how much fruit they’re destroying. And the bat’s creepy reputation probably doesn’t help, either. “I think generally bats never had a good reputation among humans,” Oleksy said. “They come out at night, we don’t see them clearly as we do birds, and we’re not used to them because they just fly at night.” However much the bats may be disliked among the general populace, though, losing them could be catastrophic to the local ecology, Florens said. The bats are important because they help disseminate the seeds of native plants. A better alternative to culling the bats would be to continue encouraging fruit growers to protect their trees with nets, Florens said. According to Oleksy, one of the reasons this tactic has been unsuccessful in the past is because the nets are not being used properly. Many people only cover the trees’ lower branches or simply drape their nets over the tops of the trees, a strategy that still allows fruit-eating animals to get close enough to nibble at the fruit. A better practice would be to hang the nets on frames that place enough distance between the trees and the netting to keep the fruit safe. And Florens also suggested encouraging more efficient harvesting practices that don’t allow so much fruit to go to waste, thus cutting down on the fruit growers’ economic losses even more. That said, Oleksy believes it’s unlikely the cull can be stopped at this point, since it’s already been announced. Both he and Florens said they expect the culling could begin any day now — and according to Oleksy it’s even more likely now, thanks to a new bill allowing for stricter control and management of the island’s biodiversity. Still, with outcry building, the bats are likely to receive greater international attention if the cull is, in fact, initiated. There’s even been talk of a boycott against Mauritian-grown fruit, Oleksy said. “People can punish this kind of decision and boycott the fruit, because [nobody] wants to buy fruit from an industry which is so destructive to the environment,” Oleksy said. “That’s one thing which I think is our last resort.” More of the planet was protected than ever before in 2015. Few noticed because it was underwater Indonesian fires are pouring huge amounts of carbon into the atmosphere The electricity innovation so controversial that it’s now before the Supreme Court For more, you can sign up for our weekly newsletter here, and follow us on Twitter here.
Buckland S.,University of Bristol |
Cole N.C.,University of Bristol |
Aguirre-Gutierrez J.,Naturalis Biodiversity Center |
Aguirre-Gutierrez J.,University of Amsterdam |
And 8 more authors.
PLoS ONE | Year: 2014
The invasion of the giant Madagascar day gecko Phelsuma grandis has increased the threats to the four endemic Mauritian day geckos (Phelsuma spp.) that have survived on mainland Mauritius. We had two main aims: (i) to predict the spatial distribution and overlap of P. grandis and the endemic geckos at a landscape level; and (ii) to investigate the effects of P. grandis on the abundance and risks of extinction of the endemic geckos at a local scale. An ensemble forecasting approach was used to predict the spatial distribution and overlap of P. grandis and the endemic geckos. We used hierarchical binomial mixture models and repeated visual estimate surveys to calculate the abundance of the endemic geckos in sites with and without P. grandis. The predicted range of each species varied from 85 km2 to 376 km2. Sixty percent of the predicted range of P. grandis overlapped with the combined predicted ranges of the four endemic geckos; 15% of the combined predicted ranges of the four endemic geckos overlapped with P. grandis. Levin's niche breadth varied from 0.140 to 0.652 between P. grandis and the four endemic geckos. The abundance of endemic geckos was 89% lower in sites with P. grandis compared to sites without P. grandis, and the endemic geckos had been extirpated at four of ten sites we surveyed with P. grandis. Species Distribution Modelling, together with the breadth metrics, predicted that P. grandis can partly share the equivalent niche with endemic species and survive in a range of environmental conditions. We provide strong evidence that smaller endemic geckos are unlikely to survive in sympatry with P. grandis. This is a cause of concern in both Mauritius and other countries with endemic species of Phelsuma. © 2014 Buckland et al. Source
Buckland S.,University of Bristol |
Cole N.C.,University of Bristol |
Godsall B.,Imperial College London |
Godsall B.,University of Sheffield |
And 4 more authors.
Global Ecology and Conservation | Year: 2014
Of 30 known subpopulations of Phelsuma guimbeaui, 18 are in patches of exotic forest and are predicted to disappear in the next decade. One possible means of mitigating the reduction in genetic diversity associated with the loss of subpopulations is to translocate "at risk" subpopulations to more secure habitats. Prior to any such intervention, it is important to identify a species' basic ecological needs. We had three main objectives: to calculate home range sizes of adult geckos; characterise habitat selection among age groups; and identify the order of importance of each habitat predictor. Habitat selection of P. guimbeaui was explored at the population, home range and microhabitat levels. Males had larger home ranges than females, and overlapped temporally with more females than males. We showed that habitat selection differed between age groups. In order of importance, tree diversity, tree species, tree height, trunk dbh and cavity density were important habitat predictors. We discuss how these data can be used to inform the choice of sites for the translocation of threatened subpopulations. Our results also highlight the importance of undertaking habitat restoration for the long-term conservation of the 12 subpopulations that survive in patches of endemic forest. © 2014 The Authors. Source