Cameras, Coyotes, and the Assumption of Equal Detectability

Remote cameras are an increasingly important tool in management and wildlife studies. However, we often do not know if they provide an unbiased sample of populations. Using a marked, radio-collared population of coyotes (Canis latrans) of known social status, we evaluated the influence of temporal (daily and seasonal) and spatial (distance between units, habitat, and proximity to human structures) factors on vulnerability to photo-captures. During 8 unbaited camera sessions of 6 weeks each, we obtained 158 coyote photographs at a photo-capture success rate of 1.6%. We were able to identify not only marked individuals, but also a number of uncollared adults through variation in their pelage. Photo-capture of adults peaked 2 weeks after we established camera stations. Annual success for photographing adult coyotes was greatest during March and April, which corresponded with the dispersal season. The majority of photo-captures occurred at night, and adult photo-captures peaked around midnight, with smaller peaks at dawn and dusk. Rather than reflecting a circadian activity pattern, nighttime captures seemed to reflect when adult coyotes were most vulnerable to photo-capture. Characteristics of camera locations, such as amount of human activity, being on roads versus trails, and habitat type, also influenced the number of photo-captures. We conclude that remote cameras do not always provide an unbiased sample of populations and that animal behavior is important to consider when using these systems. Researchers using camera techniques need to carefully consider when, where, and how cameras are placed to reduce this bias

Measuring local depletion of terrestrial game vertebrates by central-place hunters in rural Amazonia

The degree to which terrestrial vertebrate populations are depleted in tropical forests occupied by human communities has been the subject of an intense polarising debate that has important conservation implications. Conservation ecologists and practitioners are divided over the extent to which community-based subsistence offtake is compatible with ecologically functional populations of tropical forest game species. To quantify depletion envelopes of forest vertebrates around human communities, we deployed a total of 383 camera trap stations and 78 quantitative interviews to survey the peri-community areas controlled by 60 semi-subsistence communities over a combined area of over 3.2 million hectares in the Médio Juruá and Uatumã regions of Central-Western Brazilian Amazonia. Our results largely conform with prior evidence that hunting large-bodied vertebrates reduces wildlife populations near settlements, such that they are only found at a distance to settlements where they are hunted less frequently. Camera trap data suggest that a select few harvest-sensitive species, including lowland tapir, are either repelled or depleted by human communities. Nocturnal and cathemeral species were detected relatively more frequently in disturbed areas close to communities, but individual species did not necessarily shift their activity patterns. Group biomass of all species was depressed in the wider neighbourhood of urban areas rather than communities. Interview data suggest that species traits, especially group size and body mass, mediate these relationships. Large-bodied, large-group-living species are detected farther from communities as reported by experienced informants. Long-established communities in our study regions have not “emptied” the surrounding forest. Low human population density and low hunting offtake due to abundant sources of alternative aquatic protein, suggest that these communities represent a best-case scenario for sustainable hunting of wildlife for food, thereby providing a conservative assessment of game depletion. Given this ‘best-case’ camera trap and interview-based evidence for hunting depletion, regions with higher human population densities, external trade in wildlife and limited access to alternative protein will likely exhibit more severe depletion

Antiplasmodial, anti-trypanosomal, anti-leishmanial and cytotoxicity activity of selected Tanzanian medicinal plants

The antiplasmodial, anti-trypanosomal and anti-leishmanial activity of 25 plant extracts obtained from seven Tanzanian medicinal plants: Annickia (Enantia) kummeriae (Annonaceae), Artemisia annua (Asteraceae), Pseudospondias microcarpa (Anacardiaceae), Drypetes natalensis (Euphorbiaceae), Acridocarpus chloropterus (Malpighiaceae), Maytenus senegalensis (Celastraceae) and Neurautanenia mitis (Papilonaceae), were evaluated in vitro against Plasmodium falciparum K1, Trypanosoma brucei rhodesiense STIB 900 and axenic Leishmania donovani MHOM-ET-67/82. Out of the 25 extracts tested, 17 showed good antiplasmodial activity (IC50 0.04-5.0 microg/ml), 7 exhibited moderate anti-trypanosomal activity (IC50 2.3-2.8 microg/ml), while 5 displayed mild anti-leishmanial activity (IC50 8.8-9.79 microg/ml). A. kummeriae, A. annua, P. microcarpa, D. natalensis, M. senegalensis and N. mitis extracts had good antiplasmodial activity (IC50 0.04-2.1 microg/ml) and selectivity indices (29.2-2,250 microg/ml). The high antiplasmodial, moderate anti-trypanosomal and mild anti-leishmanial activity make these plants good candidates for bioassay-guided isolation of anti-protozoal compounds which could serve as new lead structures for drug developmen

Anti-protozoal activity of aporphine and protoberberine alkaloids from Annickia kummeriae (Engl. & Diels) Setten & Maas (Annonaceae)

BACKGROUND: Malaria, trypanosomiasis and leishmaniasis have an overwhelming impact in the poorest countries in the world due to their prevalence, virulence and drug resistance ability. Currently, there is inadequate armory of drugs for the treatment of malaria, trypanosomiasis and leishmaniasis. This underscores the continuing need for the discovery and development of new anti-protozoal drugs. Consequently, there is an urgent need for research aimed at the discovery and development of new effective and safe anti-plasmodial, anti-trypanosomal and anti-leishmanial drugs. METHODS: Bioassay-guided chromatographic fractionation was employed for the isolation and purification of antiprotozoal alkaloids. RESULTS: The methanol extract from the leaves of Annickia kummeriae from Tanzania exhibited a strong anti-plasmodial activity against the multi-drug resistant Plasmodium falciparum K1 strain (IC50 0.12 +/- 0.01 mug/ml, selectivity index (SI) of 250, moderate activity against Trypanosoma brucei rhodesiense STIB 900 strain (IC50 2.50 +/- 0.19 mug/ml, SI 12) and mild activity against Leishmania donovani axenic MHOM-ET-67/82 strain (IC50 9.25 +/- 0.54 mug/ml, SI 3.2). Bioassay-guided chromatographic fractionation led to the isolation of four pure alkaloids, lysicamine (1), trivalvone (2), palmatine (3), jatrorrhizine (4) and two sets of mixtures of jatrorrhizine (4) with columbamine (5) and palmatine (3) with (-)-tetrahydropalmatine (6). The alkaloids showed low cytotoxicity activity (CC50 30 - <90 mug/ml), strong to moderate anti-plasmodial activity (IC50 0.08 +/-