Anthony J. Giordano

Correlation and persistence of hunting and logging impacts on tropical rainforest mammals.

Humans influence tropical rainforest animals directly via exploitation and indirectly via habitat disturbance. Bushmeat hunting and logging occur extensively in tropical forests and have large effects on particular species. But how they alter animal diversity across landscape scales and whether their impacts are correlated across species remain less known. We used spatially widespread measurements of mammal occurrence across Malaysian Borneo and recently developed multispecies hierarchical models to assess the species richness of medium- to large-bodied terrestrial mammals while accounting for imperfect detection of all species. Hunting was associated with 31% lower species richness. Moreover, hunting remained high even where richness was very low, highlighting that hunting pressure persisted even in chronically overhunted areas. Newly logged sites had 11% lower species richness than unlogged sites, but sites logged >10 years previously had richness levels similar to those in old-growth forest. Hunting was a more serious long-term threat than logging for 91% of primate and ungulate species. Hunting and logging impacts across species were not correlated across taxa. Negative impacts of hunting were the greatest for common mammalian species, but commonness versus rarity was not related to species-specific impacts of logging. Direct human impacts appeared highly persistent and lead to defaunation of certain areas. These impacts were particularly severe for species of ecological importance as seed dispersers and herbivores. Indirect impacts were also strong but appeared to attenuate more rapidly than previously thought. The lack of correlation between direct and indirect impacts across species highlights that multifaceted conservation strategies may be needed for mammal conservation in tropical rainforests, Earths most biodiverse ecosystems.

Predicted distributions and conservation status of two threatened Southeast Asian small carnivores: the banded civet and Hose’s civet

Abstract Knowledge of the distribution and habitat preferences of a species is of paramount importance when assessing its conservation status. We used accurately recorded occurrence records and ecological niche modelling to predict the distribution of two threatened and poorly known small carnivore species that occur in Southeast Asia, the banded civet (Hemigalus derbyanus) and Hose’s civet (Diplogale hosei), and analysed their spatial niche differentiation for habitat and elevation. We then identified possible anthropogenic threats, and used our modelling predictions to recommend surveying priorities. The predicted distribution of the banded civet was principally in lowland evergreen forest in southern Myanmar/Thailand, Peninsular Malaysia, Sumatra, Borneo and three Mentawai Islands (Siberut, Sipora and South Pagai), and for Hose’s civet in evergreen forest across the higher elevation regions of Borneo. Our niche analyses suggested that there is a tendency for these two species to separate spatially along an elevation gradient: the banded civet is mainly found in lowland areas, whereas Hose’s civet primarily occurs at higher elevations. Our study strongly indicated that these two viverrids are forest-dependent species that may be threatened by forest loss, degradation and fragmentation. Field surveys should be prioritised in areas where each species is predicted to occur and no records currently exist.

Terrestrial Mammal Species Richness and Composition in Three Small Forest Patches within an Oil Palm Landscape in Sabah, Malaysian Borneo

Abstract. Small and highly degraded forest patches are usually scattered across oil palm plantation landscapes and often exist as permanent features. By using a combination of camera-trapping and line-transect methods, we evaluated the usefulness of three such forest patches (< 30 ha) for terrestrial mammal species conservation in a mature oil palm plantation located near (< 1.7 km) a large continuous tract of logged forest in eastern Sabah, Malaysian Borneo. Of the 29 terrestrial mammal species recorded in this study, 28 were found in the continuous logged forest habitat including six species that are either large-bodied, wide ranging, locally rare or are of high conservation concern. In comparison, 18 species were recorded across the three forest patches collectively; consisting mostly of species that are widespread, well-adapted to living in highly modified habitats and of low conservation concern. The presence of small forest patches within the oil palm habitat matrix seemed to be useful to some extent for some mammal species. However, many of the species were likely only transient in this habitat. The maintenance of large continuous tracts of natural forest is critical to the continued survival of many terrestrial mammal species on Borneo, particularly for species that are of high conservation value.

Assessing the Credibility of Jaguarundi (Puma yagouaroundi) Observations Using Diagnostic Criteria and Witness Qualification

Despite its legal protection, the jaguarundis (Puma yagouaroundi) status in the United States is currently unknown. Historical accounts indicate jaguarundis previously occupied habitats in extreme southern Texas. Although sightings continue to occur in the United States, none have been confirmed, and it is unclear if jaguarundis are still resident. Since the mid-1970s, however, evidence in the form of first-hand observations is suggestive of the presence of jaguarundis in Big Bend National Park. We assessed the credibility of 79 alleged jaguarundi records spanning three decades using a combination of diagnostic criteria and witness credibility. Based on this discriminatory process, we found “strong support” for 40 of these records, and believe a resident, low-density population of jaguarundis may exist in Big Bend. While not as irrefutable as physical evidence, objective reviews of species records may have merit as a tool to help evaluate whether the investment of more rigorous survey techniques is warranted.

Lowland biotic attrition revisited: body size and variation among climate change ‘winners’ and ‘losers’

The responses of lowland tropical communities to climate change will critically influence global biodiversity but remain poorly understood. If species in these systems are unable to tolerate warming, the communities—currently the most diverse on Earth—may become depauperate (‘biotic attrition’). In response to temperature changes, animals can adjust their distribution in space or their activity in time, but these two components of the niche are seldom considered together. We assessed the spatio-temporal niches of rainforest mammal species in Borneo across gradients in elevation and temperature. Most species are not predicted to experience changes in spatio-temporal niche availability, even under pessimistic warming scenarios. Responses to temperature are not predictable by phylogeny but do appear to be trait-based, being much more variable in smaller-bodied taxa. General circulation models and weather station data suggest unprecedentedly high midday temperatures later in the century; predicted responses to this warming among small-bodied species range from 9% losses to 6% gains in spatio-temporal niche availability, while larger species have close to 0% predicted change. Body mass may therefore be a key ecological trait influencing the identity of climate change winners and losers. Mammal species composition will probably change in some areas as temperatures rise, but full-scale biotic attrition this century appears unlikely.