Brian Crudge, Member: Sun Bear Expert Team, IUCN Bear Specialist Group
Dave Garshelis, Co-Chair IUCN Bear Specialist Group
Southeast Asia contains some of the highest human population densities on the planet, which pose severe constraints on sun bears (Helartcos malayanus) and Asiatic black bears (Ursus thibetanus) through habitat loss and hunting. Many bear populations exist in increasingly fragmented forest habitats surrounded by human-dominated landscapes. Conservation of bears in Southeast Asia will require action at every level – from site-specific interventions, to national action planning and range-wide strategies. Baseline population assessments and subsequent monitoring of bear populations is essential for assessing the impact of threats and to evaluate the success (or failure) of conservation interventions — both necessities for effective adaptive management.
During the 26th International Conference on Bear Research and Management held in Ljubljana, Slovenia in September 2018, we convened a workshop to discuss the development of guidelines for monitoring bears in Southeast Asia. The workshop was attended by 30 participants, most of whom had some experience monitoring bears, using a variety of techniques; however, many were not aware of the issues specific to Southeast Asia. This provided a good basis for a lively intellectual exchange of ideas.
The two-hour workshop opened with an overview of the methods typically applied to survey bears in Southeast Asia, specifically: bear sign transects; camera trapping; and villager interviews. Sign surveys are a simple and relatively rapid way of gauging presence of bears, their relative density and use of different habitats. Camera trapping, now extensively used in Southeast Asia to monitor other species or document changes in biodiversity, can yield estimates of bear occupancy and variables associated with occupancy; if baited camera sites are set specifically for bears, mark–resight estimates are obtainable by identifying individuals that stand and reveal distinctive chest markings. Village interviews are particularly useful in gaining information about population trends from the past to present, and what may be driving those trends, as perceived by local people. Also considered were non-invasive hair sampling and radio-telemetry studies, which although standard practices in North America and Europe have not been used thus far to monitor bears in Southeast Asia. The workshop then discussed each method in more detail, identifying the data outputs as well as the issues and constraints, such as expertise and effort required, sources of bias, and ability to distinguish between sympatric bear species (a particular issue to this region, where the 2 species overlap extensively).
In order to conceptualize the application of the various methods, the second half of the workshop presented several hypothetical (but realistic) scenarios to the participants, opening a free-flowing dialogue about which method or suite of methods should be applied in a given situation. The scenarios varied from how to determine species distribution and relative abundance for an entire country when there is little to no baseline data, to designing monitoring protocols for the future in an area where data already exist but seemingly better methods of monitoring are now available.
The outcomes from the workshop will be used to create a decision tree to aid researchers in determining when they should use a particular method. One clear outcome of this workshop is that there are no obviously “best” monitoring procedures.
The workshop session identified a number of key questions that will be important to address for future monitoring of bears in Southeast Asia. One was how to collect hair samples, which has proven difficult for sun bears in particular. A suggested approach is to incite rubbing behavior with some kind of lure. Collection of hair from rub trees has been used successfully for genetic mark–recapture of temperate bear species (in places where they naturally rub); this would yield enormously more information about population size and structure than can be gained with the monitoring techniques currently employed in Southeast Asia. Hair snaring for sun bears has not been effective to date due to the difficulty in sampling their short sleek fur, and due to their apparent lack of rubbing on trees.
A number of workshop participants questioned the utility of sign transects for monitoring bears going forward, due to uncertainty with regards to the precise relationship between bear sign density and population size, concerns regarding inter-observer variability in detection and classification of sign (to species and age), and advances in other techniques such as camera trapping and genetic sampling. Since bear sign surveys have been the most commonly applied method for surveying bear in Southeast Asia to date, it was concluded that research was required to elucidate the uncertainties before promoting or discontinuing use of this technique.
We would like to that all participants of the workshop for their insights and contributions. Thanks to Elizabeth Davis, San Diego Zoo Global, for documenting the workshop discussions. And thanks to Perth Zoo Wildlife Conservation Action, and International Association for Bear Research & Management Research & Conservation Grant for supporting this initiative.
Member: Sun Bear Expert Team, IUCN Bear Specialist Group
Research Programme Manager, Free the Bears
PO Box 723, Phnom Penh, Cambodia
Co-Chair IUCN Bear Specialist Group
Minnesota Department of Natural Resources
Grand Rapids, MN 55744, USA
originally published in International Bear News 2018 Fall Vol. 27 No. 3 on pages 22-23