Mapping priorities for conservation in Southeast Asia
Introduction
Southeast Asia is a global biodiversity hotspot (De Bruyn et al., 2014), however relative to other parts of the tropics there has been considerably less research across much of the Southeast Asian region (Martin et al., 2012). Southeast Asian biodiversity patterns are also highly complex, reflecting the complex biogeography of the region and demarcated and partitioned by a number of biogeographic divides (Hughes et al., 2011, Barley et al., 2015). The lack of baseline data, and limited surveys and inventories (both spatially and taxonomically) make assessing the efficacy of protected areas in protecting biodiversity highly challenging (Collen et al., 2008). In recent years the rate of species description across the region has continued to rise (Chapman, 2009), and groups analysed in detail show high rates of crypsis and taxonomic uncertainty, for example only around 50% of Southeast Asian bat species have officially been classified (Francis et al., 2010).
However the Southeast Asian region is also an undisputed hotspot of threat (Wilcove et al., 2013) and the global hotspot of threat to mammals (Schipper et al., 2008). The drivers of these threats are complex; however hunting and deforestation are among the most devastating to regional biodiversity (Hughes, 2017, Harrison et al., 2016). The region also has the highest rates of deforestation globally (Rosa et al., 2016) and some of the highest levels of landscape destruction and degradation of all global biodiversity hotspots (Sloan et al., 2014). This is especially troubling given the high regional endemicity and the potential loss of species given that Southeast Asia includes 4 of the 34 world biodiversity hotspots (De Bruyn et al., 2014).
For the majority of species across Southeast Asia there is no reliable source of range data (Verde Arregoitia, 2016), as no published data, or rigorous taxonomic data exists for the majority of species with a body size too small to be accurately be classified by camera traps (most rodents, insectivores, bats, amphibians and reptiles (Rovero et al., 2014, Ahumada et al., 2011, Ahumada et al., 2013, Beaudrot et al., 2016)). Developing regional priorities for conservation, or evaluating the adequacy of current protection on species relies upon having enough data on which to base these decisions. However with such high uncertainty in species distributions combined with rapid drivers of species loss; an evaluation of the adequacy of current protected areas is essential.
Multiple mechanisms have been advocated to develop these priorities, but the use of indicator taxa in the lieu of more complete knowledge of biodiversity patterns is one of the most widely utilised (Rodrigues and Brooks, 2007). Typically priorities have been based upon “charismatic” and easily fundable species such as the tiger (Smith et al., 2012), yet analysis shows that these “landscape species” are particularly poor surrogates of biodiversity (Jones et al., 2016). Therefore other methods to explore biodiversity patterns and develop appropriate targeted conservation strategies may be effective to the long-term survival of many species.
Given that no reliable maps exist for the majority of species, a possible way to make the best use of existing data is to collate distribution data and through combining it with environmental layers of various facets of the environment, to project the ranges of species across the region (Guisan et al., 2013, Platts et al., 2014). Once individual species distribution maps have been created it is possible to use these predicted distribution maps to ascertain centres of biodiversity, and then assay the adequacy of protected areas in these regions to explore the level of coverage and ensure that biodiversity hotspots are adequately protected. Endemism is another important point to be considered, and conserved; however mapping endemism relies on taxonomic data which does not yet exist for many of small mammal and amphibian species.
To secure a future for these species and ecosystems, protection is needed; both for biodiversity hotspots, and centres of endemism (Orme et al., 2005). Assaying the protected area coverage of biodiversity centres for these taxa is essential. Factors such as deforestation, hunting, mining, reservoir construction and numerous other factors act at higher rates and intensities outside protected areas on the majority of occasions, and as many of these species are already known from only small areas they are significantly at risk if their range does not fall within any protected areas (Li et al., 2016).
Here I explore how current knowledge of species ranges based on IUCN “expert drawn” maps compares to those produced through species distribution models and discuss the potential limitations, assumptions and challenges of both utilising both approaches. Using these two methods of exploring spatial patterns of biodiversity I compare the results, and explore the possibility of using any of the major taxa analysed (amphibians, birds, mammals and reptiles) as surrogate indicators for other taxa.
We also explore the distribution of biodiversity hotspots for four major vertebrate groups, in addition to non-flowering plants. Once biodiversity hotspots have been compared I then explore the level of protection, both for biodiversity overall and in terms of protected area coverage for each species for which sufficient data exists. Ultimately I discuss strategies for better protecting the biodiversity of one of the world's often forgotten biodiversity hotspots, and make recommendations for new spatial priorities and for sensitive approaches which provide a more effective mechanism for protecting regional biodiversity.
Section snippets
Species distribution records
Distribution data for all taxa for the last two decades were downloaded from GBIF and cleaned to remove all suspect records for all birds, mammals, reptiles and amphibians for the mainland Southeast Asian region. Additional data for bats was included using the database compiled by Hughes et al. (2012), in addition to further data for China (Zhang et al., 2009, Zhang et al., 2010). Duplicate records (i.e. repeated records of a species at a single locality) were removed from analysis, species
Biodiversity patterns
A maximum of 128 mammals, 632 birds, 330 non-flowering plants, 30 reptiles and 65 amphibians were projected to inhabit any specific 1 km2 grid cell (Fig. 1, bird family richness Supplements 3). Diversity hotspots for the four vertebrate orders considered showed considerable congruence in remaining forested areas, especially those in forested areas of Vietnam, the Thai Highlands in Chiang Mai and forested areas in Peninsula Thailand and Malaysia. Most groups additionally show high diversity in
Understanding biodiversity patterns
Model approaches provide a practicable method to explore biodiversity patterns across the landscape, however relative to IUCN maps of biodiversity a number of important issues are apparent. Firstly, due to the paucity of data for many of these species, many IUCN maps clearly have either artifactual errors, or are limited by current methodologies, and for many species more empirical methods of analysis are likely to provide more accurate and useful outcomes. Areas classified as most diverse also
Acknowledgements
I would like to thank the two anonymous reviewers and the Editor for their constructive comments, which greatly improved the structure and contents of the manuscript.
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