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Trapping Sessions (trapping + session)
Selected AbstractsUse of arboreal and terrestrial space by a small mammal community in a tropical rain forest in Borneo, MalaysiaJOURNAL OF BIOGEOGRAPHY, Issue 4 2004Konstans Wells Abstract Aim, Small mammals were live-trapped in a primary rain forest to evaluate the relative distribution of species to each other and to microhabitat properties on the ground and in the canopy. Location, Kinabalu National Park in Borneo, Sabah, Malaysia. Methods, Seven trapping sessions were conducted along two grids with 31 trap points at distances of 20 m on the ground and in the lower canopy at an average height of 13.5 m. Results, Species diversity and abundance of small mammals proved to be high: 20 species of the families Muridae, Sciuridae, Tupaiidae, Hystricidae, Viverridae and Lorisidae were trapped, with murids being dominant in both habitat layers. The terrestrial community was significantly more diverse with 16 captured species (Shannon,Wiener's diversity index = 2.47), while 11 species were trapped in the canopy ( = 1.59). The Whitehead's rat, Maxomys whiteheadi, and the red spiny rat, Maxomys surifer, dominated the terrestrial community whereas the large pencil-tailed tree mouse, Chiropodomys major, was by far the most abundant species in the canopy. Other abundant species of the canopy community, the dark-tailed tree rat, Niviventer cremoriventer, and the lesser treeshrew, Tupaia minor, were also abundant on the ground, and there was no clear boundary between arboreal and terrestrial species occurrences. Main conclusions, As most species were not confined to specific microhabitats or habitat layers, species seemed to rely on resources not necessarily restricted to certain microhabitats or habitat layers, and separation of species probably resulted mainly from a species' concentrated activity in a preferred microhabitat rather than from principal adaptations to certain habitats. Ecological segregation was stronger in the more diverse terrestrial community, though microhabitat selection was generally not sufficient to explain the co-occurrences of species and the variability between local species assemblages. Constraints on small mammal foraging efficiency in the three-dimensional more complex canopy may be responsible for the similarity of microhabitat use of all common arboreal species. Community composition was characterized by mobile species with low persistence rates, resulting in a high degree of variability in local species assemblages with similar turnover rates in both habitats. [source] Species diversity and population dynamics of rodents in a farm-fallow field mosaic system in Central TanzaniaAFRICAN JOURNAL OF ECOLOGY, Issue 2 2010Rhodes H. Makundi Abstract A Capture-Mark-Recapture study was undertaken in Central Tanzania to compare variations in community structure and population dynamics of rodents in two types of habitats. The study was conducted in fallow field mosaic habitat dominated by perennial and annual grasses (grid BEA) and a more heterogeneous habitat (grid BEB) which was previously woodland cleared of most trees with vegetation dominated by shrubs, bushes, scattered trees and perennial grass. The relative abundance of rodents in BEA was: Mastomys natalensis (73.5%) > Aethomys chrysophilus (8.9%) > Gerbilliscus vicina (7.3%) > Arvicanthis neumanni (6.1%) > Acomys spinosissimus (4.1%) and for grid BEB: M. natalensis (67.6%) > G. vicina (11.2%) > A. neumanni (10.3%) > A. chrysophilus (7.6%) > A. spinosissimus (2.9%). Graphiurus sp., Mus minutoides, Saccostomus mearnsi, Lemniscomys striatus and L. griselda were rare and only occasionally trapped in BEB. Spatial variations in population density were non-significant except for A. chrysophilus. Significant temporal variations within grids were observed, with synchrony of population peaks for some species. The rare species boosted species richness of grid BEB rather artificially, without significantly contributing to higher species diversity. Temporal variations in Simpson's Diversity indices between grids were non-significant except for three out of twenty-one trapping sessions. Résumé Une étude par capture , marquage , recapture fut entreprise dans le centre de la Tanzanie pour comparer les variations de la structure des communautés et de la dynamiques des populations de rongeurs dans deux types d'habitats. L'étude fut menée dans un habitat composé d'une mosaïque de prairies en jachères dominé par des herbes pérennes et annuelles (grille BEA) et dans un habitat plus hétérogène (grille BEB) qui était auparavant une forêt, défrichée de la plupart de ses arbres et dominée par des buissons, des arbustes, des arbres épars et des herbes pérennes. L'abondance relative des rongeurs dans BEA était la suivante : Mastomys natalensis (73,5%) > Aethomys chrysophilus (8,9%) > Gerbilliscus vicina (7,3%) > Arvicanthis neumanni (6,1%) > Acomys spinosissimus (4,1%), et pour la grille BEB: M natalensis (67,6%) > G. vicina (11,2%) > A. neumanni (10,3%) > A. chrysophilus (7,6%) > A. spinosissimus (2,9%). Graphiurus sp. Mus minutoides, Saccostomus mearnsi, Lemniscomys striatus et L. griseldaétaient rares et n'étaient que rarement capturés dans BEB. Les variations spatiales de la densité de population n'étaient pas significatives sauf pour A. chrysophilus. Des variations temporelles significatives furent observées à l'intérieur des grilles, ainsi qu'une synchronisation des pics de population pour certaines espèces. Les espèces rares renforçaient de façon plutôt artificielle la richesse en espèces de la grille BEB, sans contribuer significativement à une plus grande diversité des espèces. Des variations temporelles des indices de diversité de Simpson entre les grilles n'étaient pas significatives sauf pour trois des 21 sessions de captures. [source] Selective predation on the broad-toothed rat, Mastacomys fuscus (Rodentia: Muridae), by the introduced red fox, Vulpes vulpes (Carnivora: Canidae), in the Snowy Mountains, AustraliaAUSTRAL ECOLOGY, Issue 4 2002K. Green Abstract Since 1981 there has been debate over whether foxes (Vulpes vulpes Linnaeus) selectively prey on the broad-toothed rat (Mastacomys fuscus Thomas) relative to the bush rat (Rattus fuscipes (Waterhouse)). In the present study, three areas of the argument are examined. (i) In a study of fox diet over 3 years at both alpine and subalpine altitudes, M. fuscus outnumbered R. fuscipes in faecal remains in all seasons, in all years, and at both altitudes. Overall, M. fuscus occurred in scats five times as frequently as did R. fuscipes in the alpine zone and twice as often in the subalpine zone. (ii) Data from population studies of M. fuscus and R. fuscipes showed no evidence that M. fuscus is trap shy; neither the pattern of captures of individuals caught once, twice and so on, nor the proportion of the estimated population of each species captured during trapping sessions was significantly different. (iii) The suitable habitat for M. fuscus within the potential home ranges of foxes contributing to the subalpine fox scat collection constituted approximately 50% of the total area. However, there was no significant difference between the numbers of fox trails encountered in habitat suitable or unsuitable for M. fuscus in 19 paired transects skied in winter, indicating no preferential foraging in either habitat. Selective feeding on M. fuscus was therefore established, but how that choice is exercised was not determined. [source] Impacts of Agriculture on the Diet and Productivity of Mackinder's Eagle Owls (Bubo capensis mackinderi ) in KenyaBIOTROPICA, Issue 4 2009Darcy L. Ogada ABSTRACT Land conversion for agriculture is an increasing threat to biodiversity conservation, but its ecological effects on African birds is practically unknown. We investigated the impacts of agriculture on the diet and productivity of a small, disjunct population of Mackinder's eagle owls (Bubo capensis mackinderi ) in central Kenya. Owl diet was determined by analysis of pellets and other remains and compared to small mammal populations estimated by live trapping in two habitats. Small mammal abundance was low and averaged 7.4 small mammals/ha in farms and 0.5 small mammals/ha in grassland. Owls consumed a wide diversity of prey. The majority were mammals (87%) followed by birds (7%) and insects (5%). The percentage of small mammals in owl diet correlated positively with the relative abundance of small mammals during monthly trapping sessions. Diet composition did not influence owl breeding success. Farming activities affected owl diet composition through crop production. The amount of maize, peas, and carrots growing in farms was correlated with the abundance of Mastomys sp. and Procavia sp. in the owl's diet. Agricultural activities had a large effect on Mackinder's eagle owl diet by increasing the abundance of certain small-mammal prey and attracting owl prey to farms, though farming practices harmful to owls were observed. [source] | ||||||||||