José R. Ferrer-Paris

Factors affecting poaching risk to Vulnerable Andean bears Tremarctos ornatus in the Cordillera de Mérida, Venezuela: space, parks and people

Worldwide, many large mammals are threatened by poaching. However, understanding the causes of poaching is difficult when both hunter and hunted are elusive. One alternative is to apply regression models to opportunistically- collected data but doing so without accounting for inherent biases may result in misleading conclusions. To demonstrate a straightforward method to account for such biases, and to guide further research on an elusive Vulnerable species, we visualized spatio-temporal poaching patterns in 844 Andean bear Tremarctos ornatus presence reports from the Cordillera de Merida, Venezuela. To create maps of poaching risk we fitted two logistic regression models to a subset of 287 precisely georeferenced reports, one ignoring and one including spatial autocorrelation. Whereas the variance explained by both models was low, the second had better fit and predictive ability, and indicated that protected status had a significant positive effect on reducing poaching risk. Poaching risk increased at lower altitudes, where all indicators of human disturbance increased, although there was scant evidence that human-bear conflicts are a major direct trigger of poaching events. Because highest-risk areas were different from areas with most bear reports, we speculate that hunting may be driven by opportu- nistic encounters, rather than by purposeful searches in high- quality bear habitat. Further research comparing risk maps with bear abundance models and data on poaching behaviour will be invaluable for clarifying poaching causes and for identifying management strategies.

A brachypterous butterfly

Butterflies of the genus Redonda Adams & Bernard (Lepidoptera: Nymphalidae: Satyrinae) are endemic to the Andes of Venezuela. They comprise a monophyletic group of five allopatric taxa, females of which show various degrees of wing reduction and ability to fly. The female of Redonda bordoni Viloria & Pyrcz sp. nov. appears to be brachypterous and incapable of sustained flight, a phenomenon previously unknown within the Rhopalocera.

A NATION-WIDE STANDARDIZED BIRD SURVEY SCHEME FOR VENEZUELA

Abstract We developed a field survey protocol based on the North American Breeding Bird Survey to evaluate the efficiency and reliability of a bird monitoring scheme in the Neotropics, known as NeoMaps. A team of 21 amateur and professional ornithologists conducted bird counts at 27 locations distributed throughout Venezuela between March and April 2010. Locations selected followed a stratified spatial sampling design derived from environmental and biogeographical variables. Two complementary survey protocols were implemented in consecutive days along 40-km-long roadside transects. Three-minute point counts were performed at 50 stops, 800 m from each other on day 1. Cumulative species lists were recorded at a selection of 10 stops sampled for 9 min each, divided into three consecutive 3-min periods on day 2. We recorded 593 species at the 27 sites combined, representing 57% of the 1,033 potential species, or 43% of all known Venezuelan species. An additional 83 species were recorded outside of the formal point counts, for a total of 676 species detected. Groups such as hummingbirds and most waterbirds had unusually low numbers of both species and individuals, probably due to an abnormally dry year. Our survey methods appear to be appropriate for surveying most common diurnal non-colonial species. This is the first large-scale, systematic bird survey in Venezuela or, to our knowledge, in any other tropical country.

Indicative response of Oxysternon festivum Linné (Coleoptera: Scarabaidae) to vegetation condition in the basin of the Orinoco river, Venezuela

A good indicator species should be easy to sample, identify and measure, and be informative about its ecological context. We analysed data from a nation-wide dung beetle survey in Venezuela in order to assess the indicative response of Oxysternon festivum (Coleoptera: Scarabaeinae) to vegetation and climatic condition in the Orinoco river basin. Our approach consisted of two steps: estimating habitat suitability (HS) from historical records and mean environmental conditions, and analysing four different properties measured during a nationwide survey (occurrence, total abundance, individual body size, and total biomass), in relationship with HS and current environmental covariates measured from remote sensors. O. festivum population status could not be completely explained by historical or current conditions alone, but rather by combinations of both. It was strongly associated with forest vegetation, but abundance, biomass and body size increased under harsher (hotter and drier) climatic conditions. Thus, O. festivum seems to be sensitive to changes in vegetation cover, but tolerant to certain levels of perturbance, where it probably replaces other, more sensitive species. Fully understanding the role of O. festivum requires the analysis of its relationships to other species. We strongly recommend the development of similar protocols for the analysis of other potential ecological indicator species, drawing information from historical and contemporary sources and exploiting the available statistical tools to reveal complex patterns. Given the high diversity of dung beetles, and the growing interest in this group, several candidates will probably be found in most tropical countries.