Extinction Risks and the Conservation of Madagascar's Reptiles

Abstract

BackgroundAn understanding of the conservation status of Madagascar's endemic reptile species is needed to underpin conservation planning and priority setting in this global biodiversity hotspot, and to complement existing information on the island's mammals, birds and amphibians. We report here on the first systematic assessment of the extinction risk of endemic and native non-marine Malagasy snakes, lizards, turtles and tortoises.Methodology/Principal FindingsSpecies range maps from The IUCN Red List of Threatened Species were analysed to determine patterns in the distribution of threatened reptile species. These data, in addition to information on threats, were used to identify priority areas and actions for conservation. Thirty-nine percent of the data-sufficient Malagasy reptiles in our analyses are threatened with extinction. Areas in the north, west and south-east were identified as having more threatened species than expected and are therefore conservation priorities. Habitat degradation caused by wood harvesting and non-timber crops was the most pervasive threat. The direct removal of reptiles for international trade and human consumption threatened relatively few species, but were the primary threats for tortoises. Nine threatened reptile species are endemic to recently created protected areas.Conclusions/SignificanceWith a few alarming exceptions, the threatened endemic reptiles of Madagascar occur within the national network of protected areas, including some taxa that are only found in new protected areas. Threats to these species, however, operate inside and outside protected area boundaries. This analysis has identified priority sites for reptile conservation and completes the conservation assessment of terrestrial vertebrates in Madagascar which will facilitate conservation planning, monitoring and wise-decision making. In sharp contrast with the amphibians, there is significant reptile diversity and regional endemism in the southern and western regions of Madagascar and this study highlights the importance of these arid regions to conserving the island's biodiversity.

Biases in the current knowledge of threat status in lizards, and bridging the ‘assessment gap’

“…Australia had the lowest percentage of assessed species (15%), followed by the Neotropic, Oriental, and Afrotropic realms. Madagascar had near complete assessment (Jenkins et al, 2014) and the Nearctic had a high assessment rate (Fig. 1).…”

“…Alternatively, the huge number of lizard species in Australia (Powney et al, 2010;Wilson and Swan, 2013) may have discouraged anyone from undertaking such a task. In contrast, the near complete assessment of the lizard fauna of Madagascar is the result of a recent systematic analysis of the reptiles of the island as part of the GRA (Jenkins et al, 2014).…”

“…This is already well under way as part of the IUCN's GRA. An exemplar of this approach is Madagascar, where a series of workshops involving relevant experts lead to the near complete assessment of the islands' 373 reptile species (Jenkins et al, 2014). Similar working groups have been established for African reptiles (Tolley et al, in this issue), vipers (Maritz et al, in this issue), Anoline lizards, Chameleon's, Iguana's, and Monitor Lizards (see http://iucn.org/ about/work/programmes/species/who_we_are/ssc_specialist_ groups_and_red_list_authorities_directory/amphibians_and_ reptiles/).…”

A structurally enriched agricultural landscape maintains high reptile diversity in sub‐arid south‐western Madagascar

“…Madagascar's endemic biota is threatened by this ongoing decline of natural forests. The situation is exacerbated by human population growth and climate change (Hannah et al 2008;Jenkins et al 2014;Bradshaw, Craigie & Laurance 2015). Even though Madagascar has a long history of a protected area network, that has been extended recently (Virah-Sawmy, Gardner & Ratsifandrihamanana 2014), gaps remain in this network, compromising efficient biodiversity conservation (Jenkins et al 2014;Schwitzer et al 2014a;Runge et al 2015).…”

Conservation physiology can inform threat assessment and recovery planning processes for threatened species

“…The IUCN emphasized the need for data on endemic amphibian, reptilian and plant taxa (Callmander et al 2005, Giam et al 2010 in biodiversity hotspots Hawaii and Madagascar. Recent work has focused on status assessments for expansion of protected areas to maximize conservation of endemic richness within contrasting habitats in both areas (Callmander et al 2007, Andreone et al 2008, Miller & Porter Morgan 2011, Jenkins et al 2014, Rakotoarinivo et al 2014). Physiological research is helping to address eco-physiological performance and functions not supported by protected areas that influence population dynamics of vulnerable plant, amphibian and reptilian species (Vallan 2002, Andreone et al 2008, Blaustein et al 2012.…”