Chimpanzee feeding ecology and fallback food use in the montane forest of Nyungwe National Park,Rwanda

Almost all primates experience seasonal fluctuations in the availability of key food sources. However, the degree to which this fluctuation impacts foraging behavior varies considerably. Eastern chimpanzees (Pan troglodytes schweinfurthii) in Nyungwe National Park, Rwanda, live in a montane forest environment characterized by lower primary productivity and resource diversity than low‐elevation forests. Little is known about chimpanzee feeding ecology in montane forests, and research to date predominantly relies on indirect methods such as fecal analyses. This study is the first to use mostly observational data to examine how seasonal food availability impacts the feeding ecology of montane forest chimpanzees. We examine seasonal changes in chimpanzee diet and fallback foods (FBFs) using instantaneous scan samples and fecal analyses, supported by inspection of feeding remains. Chimpanzee fruit abundance peaked during the major dry season, with a consequent change in chimpanzee diet reflecting the abundance and diversity of key fruit species. Terrestrial herbaceous vegetation was consumed throughout the year and is defined as a “filler” FBF. In contrast to studies conducted in lower‐elevation chimpanzee sites, figs (especially Ficus lutea) were preferred resources, flowers were consumed at seasonally high rates and the proportion of non‐fig fruits in the diet were relatively low in the current study. These divergences likely result from the comparatively low environmental diversity and productivity in higher‐elevation environments.     

CETACEANS OF THE WESTERN TROPICAL INDIAN OCEAN: DISTRIBUTION, RELATIVE ABUNDANCE, AND COMPARISONS WITH CETACEAN COMMUNITIES OF TWO OTHER TROPICAL ECOSYSTEMS

We conducted a cetacean survey in the pelagic western tropical Indian Ocean (WTIO) aboard an 85-m research vessel from March to July 1995, covering 9,784 linear km. Using 25 × binoculars and line-transect methods, we recorded 589 sightings of 21 species. Stenella longirostris was the most abundant cetacean, in terms of number of individuals sighted, by an order of magnitude above any other species, while Physeter macrocephalus was the most frequently sighted, in terms of number of schools. Twelve species were widespread, seven were rare, and two were localized; our sightings include new distributional records for 12 species. Significant observations included the following: (1) Delphinus cf. tropicalis was abundant off the coast of Oman (16 sightings) and readily distinguishable in the field from D. delphis and D. capensis, (2) Balaenoptera musculus was fairly common and localized in the area of the Maldives (17 sightings), and (3) three sightings were made of an unidentified bottlenose whale tentatively referred to as Indopacetus (i. e., Mesoplodon) pacificus. We recorded 26 mixed-species cetacean schools, 43 schools with which seabirds associated, and 17 schools associated with tuna. Notable among these were mixed aggregations of Stenella attenuata, S. longirostris, yellowfin tuna, and seabirds. The cetacean community of the WTIO was similar to that of the eastern tropical Pacific (ETP) and the Gulf of Mexico (GM) in several respects. First, differences in abundance rank of individual species were small, with the result that common species were common and rare species were rare, regardless of ocean. Second, these differences in abundance were due primarily to differences in encounter rate, which varied with ocean by as much as 3,000%, and less so to school size, which generally varied less than 100%. Third, regardless of ocean, three species comprised the majority of cetaceans in the community, Stenella attenuata, S. longirostris, and S. coeruleoalba, representing 62%-82% of all individuals for all species. However, the rank order of abundance for these three species differed with ocean. Most notably, S. attenuata was abundant in the ETP and GM (abundance rank = 2 and 1, respectively) but much less common in the WTIO (abundance rank = 6). Although habitat preferences for S. attenuata appear to overlap considerably with those of S. longirostris in the ETP, our results suggest there may actually be significant differences between these two species. Detailed analysis of oceanographic correlates of distribution will be necessary in order to understand fully the habitat requirements of these pelagic dolphins, often the most conspicuous elements of tropical cetacean communities around the world.     

Rediscovery of Nebela ansata (Amoebozoa: Arcellinida) in eastern North America: biogeographical implications

Aim The question whether free‐living protists are generally cosmopolitan is currently a matter of debate. In this study we investigate the geographical distribution of a distinctive testate amoeba species, Nebela ansata, and use our data to assess the potential for highly restricted distribution patterns in some protist species. Location Global. Methods We analysed (1) 3400 testate amoeba publications from North America and other continents, (2) unpublished slides of the Penard Collection of the Natural History Museum, London, UK, and (3) 104 Sphagnum samples from eastern North America. Non‐metric multidimensional scaling (NMDS) was used to visualize the similarities in testate amoeba community composition among 1012 North American samples, including two communities that contained N. ansata. Results We rediscovered N. ansata at a site in New Jersey located close to its type locality, and in Nova Scotia. We also report the existence of an apparently unpublished museum specimen originally collected from New Jersey. Our extensive literature survey confirmed the presence of this species only in the temperate part of eastern North America. The NMDS revealed that communities with N. ansata were less similar to each other than to communities from other parts of North America, suggesting that favourable habitats for N. ansata occur in other Sphagnum‐dominated peatlands, a habitat type that has been extensively sampled in North America and elsewhere. Main conclusions These data provide an unusually convincing case of a free‐living microorganism with a very limited distribution range in the temperate part of eastern North America. The remarkably restricted distribution of N. ansata highlights the extent of our ignorance about the natural history of free‐living microorganisms, and raises questions about the lack of attention to microbial diversity in conservation biology.     

Bioherbicidal enhancement and host range expansion of a mycoherbicidal fungus via formulation approaches

Eastern black nightshade (Solanum ptycanthum; EBN) is a problematic weed partly due to its tolerance or resistance to certain herbicides. We examined the effects of an invert emulsion (IE) on the host range and weed control efficacy of the fungus Colletotrichum coccodes (NRRL strain 15547) for biocontrol of EBN. Greenhouse tests demonstrated that several other solanaceous weeds were also infected and killed, and field tests revealed >90% EBN control and dry weight reduction in plants treated with the fungus-IE formulation. These results demonstrate that this IE formulation can promote the efficacy of this bioherbicidal pathogen.