Thomas Gray

Wildlife-snaring crisis in Asian forests

THE RECENT HANOI Conference on Illegal Wildlife Trade (16 to 18 November 2016) has further highlighted the extent to which Southeast Asias wildlife is facing an extinction crisis driven by unsustainable levels of commercial hunting ([ 1 ][1]). This threat affects species both outside and within

The wildlife snaring crisis: an insidious and pervasive threat to biodiversity in Southeast Asia

Southeast Asia, a region supporting more threatened species than any other comparable continental area, is in the midst of a conservation crisis. Hunting constitutes the greatest current threat to the region’s threatened vertebrates and has resulted in many areas of largely intact forest losing much of their former vertebrate diversity and abundance. Though numerous hunting methods are used, capture with home-made snares is a major driver of this defaunation. Snares are cheaply constructed and easy to set but can be difficult to detect and are highly damaging to vertebrate populations due to their indiscriminate and wasteful nature. The primary response to snaring is the removal of snares by patrol teams: more than 200,000 snares were removed from just five of the region’s protected areas between 2010 and 2015. However due to the low opportunity costs of replacing snares, removal alone is largely ineffective. Without the proactive search, arrest and prosecution of snare-setters, along with incentives not to hunt, snares will continue to be replaced. Legislative reform that criminalises the possession of snares, and the materials used for their construction, inside and immediately adjacent to protected areas is also required. Consistent enforcement of such legislation is essential. This must be combined with longer-term demand reduction activities aimed at changing cultural attitudes and behaviors related to the consumption of wildlife products in Southeast Asia.

Bayesian occupancy monitoring for Annamite endemic biodiversity in central Vietnam

Given the crisis facing South-east Asian biodiversity evidence led conservation, including assessing the impact of innovative protected area management models, is urgently needed. Bayesian statistics provide an intuitive way to interpret biodiversity monitoring data but are largely unused, or poorly understood, by field biologists and protected area managers. We built Bayesian occupancy models for two threatened endemics of the Annamite mountains: northern yellow-cheeked gibbon Nomascus (gabriellae) annamensis and crested argus Rheinardia ocellata ocellata based on auditory surveys in three protected areas in central Vietnam. Occupancy of 2xa0×xa02-km grid cells across the landscape was 0.76xa0±xa0SE 0.03 for northern yellow-cheeked gibbon and 0.68xa0±xa0SE 0.05 for crested argus. Models predicted higher probability of gibbon occurrence at lower elevations and higher probability of crested argus presence with increasing dense forest cover. Bayesian modeling is a useful tool for assessing the effectiveness of conservation interventions and for measuring progress against conservation goals. The wider application of Bayesian statistics in conservation monitoring should allow more intuitive and user-friendly representation of sampling uncertainty, including visual representation of probability distributions and more rigorous testing for changes in the status of conservation targets.

Saving the saola from extinction.

The saola ( Pseudoryx nghetinhensis )—a primitive wild cattle species ([ 1 ][1]) endemic to the Annamite mountain range of Vietnam and Lao Peoples Democratic Republic (PDR)—was first discovered in 1992 ([ 2 ][2], [ 3 ][3]). Twenty-five years later, it is on the verge of extinction ([ 4 ][4]).

Debugging diversity - a pan-continental exploration of the potential of terrestrial blood-feeding leeches as a vertebrate monitoring tool

The use of environmental DNA (eDNA) has become an applicable noninvasive tool with which to obtain information about biodiversity. A subdiscipline of eDNA is iDNA (invertebrate‐derived DNA), where genetic material ingested by invertebrates is used to characterize the biodiversity of the species that served as hosts. While promising, these techniques are still in their infancy, as they have only been explored on limited numbers of samples from only a single or a few different locations. In this study, we investigate the suitability of iDNA extracted from more than 3,000 haematophagous terrestrial leeches as a tool for detecting a wide range of terrestrial vertebrates across five different geographical regions on three different continents. These regions cover almost the full geographical range of haematophagous terrestrial leeches, thus representing all parts of the world where this method might apply. We identify host taxa through metabarcoding coupled with high‐throughput sequencing on Illumina and IonTorrent sequencing platforms to decrease economic costs and workload and thereby make the approach attractive for practitioners in conservation management. We identified hosts in four different taxonomic vertebrate classes: mammals, birds, reptiles and amphibians, belonging to at least 42 different taxonomic families. We find that vertebrate blood ingested by haematophagous terrestrial leeches throughout their distribution is a viable source of DNA with which to examine a wide range of vertebrates. Thus, this study provides encouraging support for the potential of haematophagous terrestrial leeches as a tool for detecting and monitoring terrestrial vertebrate biodiversity.