Topic
Callosciurus
About: Callosciurus is a research topic. Over the lifetime, 60 publications have been published within this topic receiving 778 citations.
Papers published on a yearly basis
Papers
TL;DR: Hunting pressure, isolation, low abundance of large fruit trees, poor soils, and specific habitat preferences as possible explanations for the low mammal and hornbill density at Barito Ulu are discussed.
Abstract: Faunal surveys in Kalimantan have been biased towards primates in protected forests close to the coast. Relatively little has been documented on other animal species, particularly in the vast interior forests. The results of a 1996–97 census of nine large mammal and eight hornbill species in tropical lowland forest in Barito Ulu, Central Kalimantan are reported here. Pigs Sus barbatus had the highest biomass, but this was due to large numbers migrating through the study area over 4 months and the resident population is probably low. Langurs Presbytis rubicunda and hybrid gibbons Hylobates mulleri × agilis had the highest biomass of all resident species. Orang-utans Pongo pygmaeus were absent from the area during the study period and pig-tailed macaques Macaca nemestrina were rarely seen. The resident hornbill species (Anthracoceros malayanus, Anorrhinus galeritus, Buceros vigil and B. rhinoceros) had high densities compared to that reported from lowland areas, but overall hornbill density was low due to the absence of the nomadic Aceros corrugatus and A. undulatus, except during peak fruit abundance. Sun bears Helarctos malayanus, long-tailed macaques M. fascicularis, muntjacs Muntiacus spp. and mouse deer Tragulus spp. were at low densities. Density of two large squirrel species, Ratufa affinis and Sundasciurus hippiurus, was lower than has been reported in Sarawak, but the density of Prevost's squirrel Callosciurus prevostii was higher. We discuss hunting pressure, isolation, low abundance of large fruit trees, poor soils, and specific habitat preferences as possible explanations for the low mammal and hornbill density at Barito Ulu.
94 citations
1 Jan 2007
TL;DR: In this article, the authors reviewed the worldwide distribution of tree squirrel introductions and detail their nearly universal success, and discussed existing management strategies planned for some species, focusing on an introduced population of Mexican red-bellied squirrels (Sciurus aureogaster).
Abstract: The impact of invasive species on native biodiversity is increasing worldwide. Mammalian invaders are formidable ecological and economic threats, and tree squirrels are models of such challenges. We review the worldwide distribution of tree squirrel introductions and detail their nearly universal success. The biological characteristics of tree squirrels that enable success as invasive species are: high reproductive potential, high vagility, diverse food habits, ability to construct nests, and plasticity in human-impacted landscapes. We document costs and benefits of tree squirrel introductions, and discuss existing management strategies planned for some species. We focus on an introduced population of Mexican red-bellied squirrels (Sciurus aureogaster) found in Biscayne National Park, Florida, United States. Originally introduced to Elliot Key in 1938, the population expanded until Hurricane Andrew in 1992. Thought to be extirpated, recent sightings initiated a project to assess status and distribution within the Park. A field study has provided valuable information on potential and realized impacts that the squirrel population has on the native ecosystem that includes several species of conservation concern. Management strategies for Mexican redbellied squirrels can be formed after research to develop prudent and effective means to meet the challenges that result from control measures to deal with this exotic species.
48 citations
TL;DR: Calling frequency, intensity, duration, and sound structure of each call were compared among three species, and related to habitat selection.
Abstract: Anti-predator vocalizations were studied in three species of tree squirrel, Callosciurus , in Ulu Gombak, Selangor Darul Ehsan, Malaysia. In the study area (ca. 10 ha), C. notatus was dominant in areas of low tree density, C. nigrovittatus in dense forests with tall trees, and C. caniceps in shrubs. All three species produced different calls to different predators; terrestrial carnivores, raptors, and snakes. Each signal caused conspecific individuals to adopt a different escape strategy. On hearing the repetitious, staccato barks toward carnivores, neighboring individuals ran up trees. A single bark was produced when raptors flew in the distance, which made conspecifics freeze. However, squirrels produced a rattle sound toward raptors in cases of close encounter. Squirrels moved toward the sound source of squeaks to snakes, and mobbed in a group. Calling frequency, intensity, duration, and sound structure of each call were compared among three species, and related to habitat selection.
37 citations
TL;DR: Italian and Belgian squirrels formed an independent taxonomic lineage in genetic analyses, whose taxonomic rank needs further investigation, and genetic data revealed close similarity between French squirrels and Pallas's squirrels, Callosciurus erythraeus, from Taiwan, China.
Abstract: Integrative taxonomy, a multi-disciplinary approach adding modern techniques to traditional morphology-based methods (e.g. molecular and morphological criteria), can play an important role in bioinvasion research to identify introduced taxa, discover pathways of introduction and inform authorities to control and prevent future introductions. The present study is the first on introduced populations of Callosciurus, Asiatic tree squirrels, known as potentially invasive species in Europe (Italy, Belgium and France). We combined molecular (mitochondrial DNA markers: CoxI, D-loop) and morphometric analysis on skulls, comparing them to the widest morphological and molecular datasets ever assembled for Callosciurus. Squirrels collected in Italy and Belgium share the same haplotypes and skull characteristics, but are conspicuously different from the French population in Antibes. Genetic data revealed close similarity between French squirrels and Pallas's squirrels, Callosciurus erythraeus, from Taiwan, China. Italian and Belgian squirrels formed an independent taxonomic lineage in genetic analyses, whose taxonomic rank needs further investigation. The morphological and morphometric characteristics of these 2 populations are, however, similar to known specimens assigned to Callosciurus erythraeus. These results may indicate a common origin for the populations found in Belgium and Italy. In contrast, French specimens suggest an independent introduction event of squirrels originating from Asia.
34 citations
TL;DR: Observations suggest that there were differences in the importance of figs in the diets of sympatric langurs (Presbytis) and congeneric squirrels.
Abstract: During a study of avian fig-eating at Kuala Lompat, Malaysia, observations were also made of fig-eating by mammals. Four species of primate, seven species of squirrel, and two species of civet consumed figs. Twenty-six species ofFicus were of importance to arboreal mammals. Observations suggest that there were differences in the importance of figs in the diets of sympatric langurs (Presbytis) and congeneric squirrels. Dusky langursPresbytis obscura ate carbohydrate-rich ripe figs despite their ruminant-like digestive system and the danger of bloat.
31 citations
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Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 2 |
| 2020 | 1 |
| 2019 | 1 |
| 2018 | 2 |
| 2017 | 4 |
| 2016 | 3 |