Habitat degradation and indiscriminate hunting differentially impact faunal communities in the Southeast Asian tropical biodiversity hotspot

Tilker, Andrew; Abrams, Jesse F.; Mohamed, Azlan; Nguyen, An; Wong, Seth T.; Sollmann, Rahel; Niedballa, Jürgen; Bhagwat, Tejas; Gray, Thomas N. E.; Rawson, Benjamin M.; Guegan, Francois; Kissing, Johnny; Wegmann, Martin; Wilting, Andreas

doi:10.1038/s42003-019-0640-y

Cited by 59 publications

(63 citation statements)

References 70 publications

(88 reference statements)

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“…Given the largely homogenous landscape-scale forest structure and habitat in our study sites, the low predicted species richness is likely indicative of a community that has undergone severe hunting-driven defaunation. The extent of faunal impoverishment is further supported by the fact that we failed to record almost half of the mammal community would be expected to occur in these sites based on historical distribution maps (Tilker et al, 2019).…”

Section: Discussionmentioning

confidence: 74%

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Identifying conservation priorities in a defaunated tropical biodiversity hotspot

Tilker

Abrams

Nguyen

et al. 2020

Diversity and Distributions

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Aim Unsustainable hunting is leading to widespread defaunation across the tropics. To mitigate against this threat with limited conservation resources, stakeholders must make decisions on where to focus anti‐poaching activities. Identifying priority areas in a robust way allows decision‐makers to target areas of conservation importance, therefore maximizing the impact of conservation interventions. Location Annamite mountains, Vietnam and Laos. Methods We conducted systematic landscape‐scale surveys across five study sites (four protected areas, one unprotected area) using camera‐trapping and leech‐derived environmental DNA. We analysed detections within a Bayesian multispecies occupancy framework to evaluate species responses to environmental and anthropogenic influences. Species responses were then used to predict occurrence to unsampled regions. We used predicted species richness maps and occurrence of endemic species to identify areas of conservation importance for targeted conservation interventions. Results Analyses showed that habitat‐based covariates were uninformative. Our final model therefore incorporated three anthropogenic covariates as well as elevation, which reflects both ecological and anthropogenic factors. Conservation‐priority species tended to found in areas that are more remote now or have been less accessible in the past, and at higher elevations. Predicted species richness was low and broadly similar across the sites, but slightly higher in the more remote site. Occupancy of the three endemic species showed a similar trend. Main conclusion Identifying spatial patterns of biodiversity in heavily defaunated landscapes may require novel methodological and analytical approaches. Our results indicate that to build robust prediction maps it is beneficial to sample over large spatial scales, use multiple detection methods to increase detections for rare species, include anthropogenic covariates that capture different aspects of hunting pressure and analyse data within a Bayesian multispecies framework. Our models further suggest that more remote areas should be prioritized for anti‐poaching efforts to prevent the loss of rare and endemic species.

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Section: Discussionmentioning

confidence: 74%

“…In many ways, our study landscape exemplifies classical “empty forest syndrome” (Redford, ). All large‐ and medium‐sized predators (with the exception of Asiatic black bear), as well as all megaherbivores, appear to be locally extirpated (Tilker et al, ). Large ungulates have been hunted out from most of the landscape (Figure ).…”

Section: Discussionmentioning

confidence: 99%

Identifying conservation priorities in a defaunated tropical biodiversity hotspot

Tilker

Abrams

Nguyen

et al. 2020

Diversity and Distributions

Self Cite

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“…In one seizure incident alone, as recently as October 2019, over 800 wildlife parts were found in Sarawak, of which 183 were bear gall bladders (Ling 2019). This is also reflected elsewhere in Southeast Asia, where indiscriminate and illegal use of snares is decimating vertebrates across the region, including bears (Harrison et al 2016b, Gray et al 2018, Symes et al 2018, Tilker et al 2019. In Cambodia, seizure rates involving bears have reportedly decreased in recent years and this is thought to be due to declining bear populations, in addition to trade becoming more discreet (Crudge et al 2019).…”

Section: Discussionmentioning

confidence: 99%

Illegal trade of sun bear parts in the Malaysian states of Sabah and Sarawak

Gomez¹,

Shepherd²,

Khoo³

2020

Endang. Species. Res.

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Malaysia is a known source and consumer of bear bile products in Asia, and sun bears are persistently poached to meet the demand for traditional Chinese medicine (TCM). Surveys of TCM outlets in the East Malaysian states of Sabah and Sarawak were conducted in 2018 and 2019 as part of continuing efforts to monitor the availability of bear bile products in the country. Despite being illegal, the trade in bears and their parts persists, although with fewer TCM outlets offering such products in comparison to numbers reported in previous studies. In 2012, 42% of TCM outlets in Sabah and 35.4% in Sarawak were found to contain bear bile products. This has since dropped to 35% in Sabah and 19.3% in Sarawak in 2018-2019. Gall bladders were the main type of commodity for sale in both states, and were reportedly sourced predominantly by indigenous people. It was evident that most retailers surveyed were aware that the trade in bears and their parts was strictly prohibited, and some traders claim to have stopped selling illegal bear products for this reason. However, some traders who continue to trade in these illegal commodities have become more discreet. These factors contribute to the reduction in TCM outlets observed selling bear bile products. This reduction may also be due to diminishing sun bear populations, as some traders have claimed to have stopped selling bear bile products because of the rarity of or difficulty in procuring genuine bear gall bladders. The threat of illegal trade, combined with loss and degradation of suitable habitat and food resources as well as conflict with humans, puts sun bears at considerable risk. Efforts to mitigate these threats are urgently needed. Reduction of demand for bear parts is essential, as is stronger legal protection, enhanced enforcement and increased community involvement in bear conservation actions to ensure the long-term survival of viable bear populations in Asia.

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“…Surprisingly, human footprint indices did not correlate well with faunal intactness (Supplementary Figure 1), because while threats such as habitat loss may correlate well, several major threats to faunal intactness (e.g., hunting, invasive species) are not properly accounted for by the human footprint maps (Benítez-López et al, 2019;Belote et al, 2020). There is considerable geographic variation in patterns of hunting pressure, but many tropical forest regions characterized by relatively low human densities and land cover change have also suffered from extensive and unsustainable hunting pressure (Redford, 1992;Tilker et al, 2019); invasive predators have encroached into wilderness areas far from infrastructure networks (Doherty et al, 2016); and diseases such as ebola can spread deep into remote forests (Rizkalla et al, 2007). None of these threats are picked up by remote sensing tools.…”

Section: Discussionmentioning

confidence: 99%

Where Might We Find Ecologically Intact Communities?

Plumptre¹,

Baisero²,

Belote³

et al. 2021

Front. For. Glob. Change

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Conservation efforts should target the few remaining areas of the world that represent outstanding examples of ecological integrity and aim to restore ecological integrity to a much broader area of the world with intact habitat and minimal species loss while this is still possible. There have been many assessments of “intactness” in recent years but most of these use measures of anthropogenic impact at a site, rather than faunal intactness or ecological integrity. This paper makes the first assessment of faunal intactness for the global terrestrial land surface and assesses how many ecoregions have sites that could qualify as Key Biodiversity Areas (KBAs – sites contributing significantly to the global persistence of biodiversity) based on their outstanding ecological integrity (under KBA Criterion C). Three datasets are combined on species loss at sites to create a new spatially explicit map of numbers of species extirpated. Based on this map it is estimated that no more than 2.9% of the land surface can be considered to be faunally intact. Additionally, using habitat/density distribution data for 15 large mammals we also make an initial assessment of areas where mammal densities are reduced, showing a further decrease in surface area to 2.8% of the land surface that could be considered functionally intact. Only 11% of the functionally intact areas that were identified are included within existing protected areas, and only 4% within existing KBAs triggered by other criteria. Our findings show that the number of ecoregions that could qualify as Criterion C KBAs could potentially increase land area up to 20% if their faunal composition was restored with the reintroduction of 1–5 species. Hence, if all necessary requirements are met in order to reintroduce species and regain faunal integrity, this will increase ecological integrity across much of the area where human impacts are low (human footprint ≤4). Focusing restoration efforts in these areas could significantly increase the area of the planet with full ecological integrity.

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Habitat degradation and indiscriminate hunting differentially impact faunal communities in the Southeast Asian tropical biodiversity hotspot

Cited by 59 publications

References 70 publications

Identifying conservation priorities in a defaunated tropical biodiversity hotspot

Identifying conservation priorities in a defaunated tropical biodiversity hotspot

Illegal trade of sun bear parts in the Malaysian states of Sabah and Sarawak

Where Might We Find Ecologically Intact Communities?

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