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Small Mammal Community (small + mammal_community)

Distribution by Scientific Domains

Life Sciences	85%

Selected Abstracts

Effects of Fragmentation of Araucarian Vine Forest on Small Mammal Communities

CONSERVATION BIOLOGY, Issue 4 2000
Jocelyn M. Bentley
We examined the abundance of small mammal species in forests, corridors, remnants of araucarian vine forest, and Araucaria cunninghamii plantations and pastures. None of the forest mammal species persisted following conversion of forest to pasture. Plantations supported lowered abundances of a subset of forest species that were mainly habitat generalists with respect to their occurrence in different floristic types of undisturbed native forest. Within plantations, an increased subcanopy cover was associated with a more forest-like small mammal assemblage. Species' responses to habitat fragmentation varied. The floristic habitat generalists were largely tolerant of habitat fragmentation, their abundance being similar in forests, corridors, and remnants, and were capable of persisting in remnants a few hectares in area. Floristic habitat specialists were vulnerable to habitat fragmentation and thus were abundant in continuous forest, were less abundant in corridors, and were generally absent from remnants. Species that avoid the corridor matrix and are therefore constrained to the corridor may be disadvantaged by the linearity of the habitat, consistent with the predictions of central-place foraging theory. Although small remnants and corridors provide habitat for some species, those that are more specialized in their use of undisturbed habitat types require the retention or reestablishment of large intact areas. Resumen: La pérdida de hábitat y la fragmentación son amenazas importantes para la sobrevivencia de la fauna que depende del bosque. Examinamos la abundancia de especies de mamíferos pequeños en bosques, corredores, y en remanentes de bosques de vid araucarios y en plantaciones de Araucaria cunninghamii y pastizales. Ninguna de las especies de mamíferos del bosque persistió después de la conversión del bosque a pastizal. Las plantaciones favorecieron abundancias menores de un conjunto de especies del bosque integrado principalmente por generalistas de hábitat con respecto a su presencia en diferentes tipos florísticos de bosque nativo sin perturbar. Dentro de las plantaciones, cuanto mayor era la cobertura por debajo del dosel más se parecía el ensamblaje de mamíferos pequeños al del bosque. Las respuestas de las especies a la fragmentación del hábitat fueron variadas. Los generalistas del hábitat florístico por lo general toleraban la fragmentación del hábitat ( la abundancia en bosques, corredores y remanentes era similar) y fueron capaces de persistir en remanentes de unas pocas hectáreas de extensión. Los especialistas de hábitat florístico fueron vulnerables a la fragmentación del hábitat y por ello fueron más abundantes en bosques continuos, menos abundantes en corredores y generalmente ausentes en los remanentes. Las especies que evitaron la matriz de corredores y por lo tanto se encuentran limitadas al corredor pueden estar en desventaja por la linearidad del hábitat, consistente con las predicciones de la teoría del forrajeo de sitio central. A pesar de que los remanentes pequeños y los corredores proveen hábitat para algunas especies, aquéllas que son más especializadas en el uso de tipos de hábitat sin perturbar requieren de la retención o del restablecimiento de áreas intactas grandes. [source]

Factors Affecting the Small Mammal Community Inside and Outside Katavi National Park, Tanzania1

BIOTROPICA, Issue 2 2002
T. M. Caro
ABSTRACT Small mammal trapping showed that a minimum of 12 species live in and around Katavi National Park in western Tanzania. Species richness and abundance were greater outside the park than inside, extending results of an earlier study. Species richness and abundance were not significantly associated with vegetation cover or plant biomass but were negatively correlated with seed diversity, seed biomass, and possibly small carnivore abundance. Unfortunately, small mammal diets are unknown in this ecosystem and it can be argued that carnivores are unlikely to reduce species diversity, casting doubt on the importance of these variables. While the factors causing small mammals to fare poorly in this protected area are not yet understood, reduced food availability remains the best candidate. [source]

Conversion of sagebrush shrublands to exotic annual grasslands negatively impacts small mammal communities

DIVERSITY AND DISTRIBUTIONS, Issue 5 2009
Steven M. Ostoja
Abstract Aim, The exotic annual cheatgrass (Bromus tectorum) is fast replacing sagebrush (Artemisia tridentata) communities throughout the Great Basin Desert and nearby regions in the Western United States, impacting native plant communities and altering fire regimes, which contributes to the long-term persistence of this weedy species. The effect of this conversion on native faunal communities remains largely unexamined. We assess the impact of conversion from native perennial to exotic annual plant communities on desert rodent communities. Location, Wyoming big sagebrush shrublands and nearby sites previously converted to cheatgrass-dominated annual grasslands in the Great Basin Desert, Utah, USA. Methods, At two sites in Tooele County, Utah, USA, we investigated with Sherman live trapping whether intact sagebrush vegetation and nearby converted Bromus tectorum -dominated vegetation differed in rodent abundance, diversity and community composition. Results, Rodent abundance and species richness were considerably greater in sagebrush plots than in cheatgrass-dominated plots. Nine species were captured in sagebrush plots; five of these were also trapped in cheatgrass plots, all at lower abundances than in the sagebrush. In contrast, cheatgrass-dominated plots had no species that were not found in sagebrush. In addition, the site that had been converted to cheatgrass longer had lower abundances of rodents than the site more recently converted to cheatgrass-dominated plots. Despite large differences in abundances and species richness, Simpson's D diversity and Shannon-Wiener diversity and Brillouin evenness indices did not differ between sagebrush and cheatgrass-dominated plots. Main conclusions, This survey of rodent communities in native sagebrush and in converted cheatgrass-dominated vegetation suggests that the abundances and community composition of rodents may be shifting, potentially at the larger spatial scale of the entire Great Basin, where cheatgrass continues to invade and dominate more landscape at a rapid rate. [source]

Indications of higher diversity and abundance of small rodents in human-influenced Sudanian savannah than in the Niokolo Koba National Park (Senegal)

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2010
Adam Kone
Abstract Expansion of human activities in the Sudanian savannah is changing natural habitats together with their animal communities. The abundance and diversity of small mammal communities were investigated in human-influenced savannahs in close proximity to Niokolo Koba National Park (NKNP) in south-eastern Senegal and compared with those from NKNP. Two localities were sampled in natural and two in human-influenced areas during two dry and two rainy seasons. Total sampling effort was 5400 trap-nights. Ninety-eight individuals of eleven species were captured outside NKNP, while only 28 individuals of five rodent species were caught inside the park (all of which were found also outside NKNP). The most abundant species outside NKNP was Mastomys erythroleucus, while inside NKNP it was Praomys daltoni. Both relative abundance and diversity were significantly higher in human-influenced landscape than in natural savannahs of NKNP. The difference in species richness may be linked with lower population densities of certain species in NKNP and the effect of traditional agriculture, which may support the presence of species typical for deforested landscape. Furthermore, food availability, and predator abundances are discussed as possible reasons for the higher rodent abundances outside NKNP. Résumé L'expansion des activités humaines dans la savane soudanienne est en train de modifier des habitats naturels et, avec eux, les communautés animales. L'abondance et la diversité de communautés de petits mammifères ont étéétudiées dans des savanes soumises à l'influence humaine à proximité immédiate du Parc national de Niokolo Koba (PNNK), au sud-est du Sénégal, et elles ont été comparées à celles du PNNK. On a prélevé des échantillons dans deux endroits situés dans des zones naturelles et dans deux autres influencés par les hommes, pendant deux saisons sèches et deux saisons des pluies. L'effort total d'échantillonnage représentait 5400 nuits de piégeage. On a capturé 98 individus appartenant à eleven espèces en dehors du PNNK alors que, dans le parc, on n'a capturé que 28 individus appartenant à cinq espèces de rongeurs (et dont toutes se retrouvent aussi à l'extérieur du PNNK). L'espèce la plus abondante en dehors du parc était Mastomys erythroleucus alors que, dans le PNNK, c'était Praomys daltoni. L'abondance relative et la diversitéétaient significativement plus grandes dans le paysage sous influence humaine que dans les savanes naturelles du PNNK. La différence de la richesse en espèces est peut-être liée à la plus faible densité de population de certaines espèces dans le PNNK et à l'effet de l'agriculture traditionnelle qui peut favoriser la présence d'espèces typiques de paysages où la forêt a été coupée. De plus, on discute de la disponibilité en nourriture et de l'abondance de prédateurs qui pourraient être des raisons de la plus grande abondance de rongeurs en dehors du PNNK. [source]

Use of arboreal and terrestrial space by a small mammal community in a tropical rain forest in Borneo, Malaysia

JOURNAL OF BIOGEOGRAPHY, Issue 4 2004
Konstans 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]

Diversity, dynamics and reproduction in a community of small mammals in Upper Guinea, with emphasis on pygmy mice ecology

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2010
Elisabeth Fichet-Calvet
Abstract As part of a large survey on reservoirs of Lassa fever in Guinea, three villages were investigated in high endemic zone, close to Sierra Leone border. Biodiversity of the small mammal community is presented in this study through a standardized trapping in houses, cultivations and forest. Identification of the small mammals was based on morphology and by molecular technique for sibling species. Of the 1123 specimens collected in 2003,2005, we identified seventeen species (thirteen Muridae, four Soricidae), leading to high diversity (Shannon index = 1.6,1.8) and high equitability (evenness index = 0.7,0.8) in cultivations and forest. In houses conversely, the rodent community was dominated by Mastomys natalensis (95,98%), leading to low diversity and equitability. Dynamics and reproduction were investigated in two species of pygmy mice, Mus mattheyi and Mus minutoides, two species of Praomys, P. daltoni and P. rostratus, and in Mastomys erythroleucus. The pygmy mice were abundant in cultivations in early rainy season, and reproduced from rainy to dry season. Praomys daltoni was also found more abundant in cultivations and seemed to reproduce between rainy and dry season, whereas P. rostratus preferred forest and cultivations in late rainy season, and reproduced throughout the year. Finally, M. erythroleucus was more abundant in forest in dry season, and seemed to reproduce from late rainy to dry season. This species had a low occurrence (6.5%) in the Faranah's zone, and probably lived at its southern limit in Guinea. The presence of other Murinae, such as M. natalensis, Praomys spp as possible competitors in the same habitats, is discussed. For the first time, this study relates population biology of pygmy mice with molecular identification. Résumé Dans le cadre d'une vaste étude des réservoirs de la fièvre de Lassa en Guinée, trois villages ont étéétudiés dans une zone de forte endémie près de la frontière de la Sierra Leone. La biodiversité de la communauté de petits mammifères est présentée dans cette étude grâce à un piégeage standardisé dans les maisons, les cultures et les forêts. L'identification des petits mammifères est réalisée sur la base de leur morphologie et de techniques moléculaires dans le cas d'espèces jumelles. Parmi les 1123 spécimens récoltés de 2003 à 2005, nous avons identifié dix-sept espèces (treize Muridae, quatre Soricidae), indiquant une grande diversité (Indice de Shannon = 1,6 à 1,8) et une grande équitabilité (indice d'équitabilité = 0,7 à 0,8) dans les cultures et les forêts. Dans les maisons en revanche, la communauté de rongeurs était dominée par Mastomys natalensis (95 à 98%), conduisant à une faible diversité et équitabilité. La dynamique et la reproduction de deux espèces de souris naines, Mus mattheyi et M. minutoides, deux espèces de Praomys, P. daltoni et P. rostratus, et de Mastomys erythroleucus ont étéétudiées également. Les souris naines étaient abondantes dans les cultures au début de la saison des pluies, se reproduisant de la saison des pluies à la saison sèche. Praomys daltoni fut aussi trouvé en plus grand nombre dans les cultures et semblait se reproduire entre la saison des pluies et la saison sèche alors que P. rostratus préférait les forêts et les cultures à la fin de la saison des pluies et se reproduisait toute l'année. Enfin, M. erythroleucusétait plus abondant en forêt en saison sèche et semblait se reproduire de la fin de la saison des pluies à la saison sèche. Cette espèce était peu présente (6,5%) dans la zone de Faranah et était probablement en Guinée à la limite sud de son aire de répartition. La présence d'autres Murinae, comme M. natalensis et Praomys spp. est discutée en tant que compétiteurs possibles dans les même habitats. Pour la première fois, cette étude relate la biologie des populations de souris naines grâce à une identification moléculaire. [source]

The small mammal community of a coastal site of south-west Mauritania

AFRICAN JOURNAL OF ECOLOGY, Issue 1 2002
L. Granjon
Abstract The small mammal community of a coastal site of south-western Mauritania was monitored using live trapping, owl pellet analysis and nocturnal visual censuses. Ten species of rodents and two shrews were recorded. Gerbillid rodents (Gerbillus nanus, G. gerbillus, G. tarabuli, G. nigeriae and Taterillus arenarius) were the most prevalent in traps, whereas a relatively large proportion of owl pellets were made up of a murid rodent, Mastomys huberti. The presence of two species of murids (M. huberti and Arvicanthis niloticus) in this presaharian environment is made possible by the presence of small patches of green vegetation associated with localized fresh water inputs. The contradiction of results from the sampling methods indicate potential biases in the determination of community composition and relative species abundance. Results are also discussed in estimating the potential role of predation and competition in this small mammal community. Résumé On a surveillé de façon continue la communauté de petits mammifères d'un site côtier du sud-ouest de la Mauritanie en servant de pièges, de l'analyse des pelotes de réjection des chouettes et de recensements visuels nocturnes. On a rapporté la présence de 10 espèces de rongeurs et de deux musaraignes. Les Gerbillidés (Gerbillus nanus, G. gerbillus, G. tarabuli, G. nigeriae et Taterillus arenarius) étaient ceux qu'on trouvait le plus dans les pièges, alors qu'une assez forte proportion de pelotes étaient constituées des restes d'un rongeur muridé, Mastomys huberti. La présence de deux espèces de muridés (M. huberti et Arvicanthis niloticus) dans cet environnement pré-saharien est rendue possible par de petits îlots de végétation verdoyante associés à des arrivées locales d'eau douce. La contradiction entre les résultats obtenus par les différentes méthodes d'échantillonnage indique la possibilité de biais dans la détermination de la composition de la communauté et l'abondance relative des espèces. On discute aussi les résultats en estimant le rôle potentiel de la prédation et de la compétition dans cette communauté de petits mammifères. [source]