The influence of sex and reproductive state on diet preference in four terrestrial mammals of the French Guianan rain forest

1997 ◽  
Vol 75 (6) ◽  
pp. 929-935 ◽  
Author(s):  
O. Henry

The diets of males and pregnant and nonpregnant females were studied in four French Guianan mammal species, three rodents and one artiodactyl, illustrating a gradient of size, mass, and gestation, and thus of energy and protein requirements. In the rodents (Oryzomys capito, Proechimys cuvieri, Dasyprocta leporina), males were more frugivorous than females, whereas the reverse was the case in the artiodactyl (Tayassu tajacu). For all species, males ate the most pulp, while pregnant females focused on seeds or animal matter. Nevertheless, males and females appeared to be opportunistic foragers, with similar feeding strategies throughout the year. A comparative analysis of stomach contents showed that the diets of males and nonpregnant females were quite comparable, while significant differences occurred in gravid females (especially of the two smallest species). Intra-individual differences gradually decreased from O. capito to T. tajacu, possibly as a result of closer male and female cohabitation as well as lower relative energy and protein requirements for pregnant females of the larger species. Finally, for the two smallest species, reproductive activity was correlated with seed and (or) animal matter intake.

1997 ◽  
Vol 24 (6) ◽  
pp. 737 ◽  
Author(s):  
Ross L. Goldingay ◽  
Robert J. Whelan

The distribution and abundance of small terrestrial mammals were assessed in forest adjacent to powerline easements at three different sites in New South Wales. At each site, four transects of 300 m length extended into the forest from the edge of the easement. The abundances of two native species (Antechinus stuartii, Rattus fuscipes) did not differ significantly with distance from the easement but abundances differed markedly among sites. Mammals were captured in only one easement where dense vegetation was present. Feral carnivores, which may mediate edge effects on small mammals, were surveyed by using hair-sampling tubes. Cats and dogs were detected only 50–200 m inside the forest. Foxes were not detected by hair-tubes but were observed on two easements. These results suggest that powerline easements may not create edge effects in eucalypt forest for some native mammal species, although further studies are needed to determine the generality of this conclusion. We recommend that easement management should be more benign to native mammals, given the ubiquity of this form of habitat fragmentation. Promotion of dense vegetative cover and habitat linkages within easements could achieve this.


2019 ◽  
Author(s):  
Maria Paniw ◽  
Tamora James ◽  
C. Ruth Archer ◽  
Gesa Römer ◽  
Sam Levin ◽  
...  

ABSTRACTApproximately 25 % of mammals are threatened globally with extinction, a risk that is amplified under climate change1. Persistence under climate change is determined by the combined effects of climatic factors on multiple demographic rates (survival, development, reproduction), and hence, on population dynamics2. Thus, to quantify which species and places on Earth are most vulnerable to climate-driven extinction, a global understanding of how demographic rates respond to climate is needed3. We synthesise information on such responses in terrestrial mammals, where extensive demographic data are available4. Given the importance of assessing the full spectrum of responses, we focus on studies that quantitatively link climate to multiple demographic rates. We identify 106 such studies, corresponding to 86 mammal species. We reveal a strong mismatch between the locations of demographic studies and the regions and taxa currently recognised as most vulnerable to climate change5,6. Moreover, we show that the effects of climate change on mammals will operate via complex demographic mechanisms: a vast majority of mammal populations display projected increases in some demographic rates but declines in others. Assessments of population viability under climate change therefore need to account for multiple demographic responses. We advocate to prioritise coordinated actions to assess mammal demography holistically for effective conservation worldwide.


2016 ◽  
Vol 46 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Nathália Carina dos Santos SILVA ◽  
Aluízio José Lopes da COSTA ◽  
José LOUVISE ◽  
Bruno Eleres SOARES ◽  
Vanessa Cristine e Souza REIS ◽  
...  

ABSTRACTResource partitioning is important for species coexistence. Species with similar ecomorphology are potential competitors, especially when phylogenetically close, due to niche conservatism. The aim of this study was to investigate the resource partitioning among populations of two species of lebiasinids (Copella nigrofasciata and Pyrrhulina aff. brevis) that co-occur in a first-order Amazonian stream, analyzing the trophic ecology, feeding strategies and ecomorphological attributes related to the use of food and space by these species. Fish were captured in May and September 2010. The stomach contents of 60 individuals were analyzed and quantified volumetrically to characterize the feeding ecology of both species. Eleven morphological attributes were measured in 20 specimens and combined in nine ecomorphological indices. Both species had an omnivorous-invertivorous diet and consumed predominantly allochthonous items. Both showed a tendency to a generalist diet, but intrapopulational variation in resource use was also detected. Overall feeding niche overlap was high, but differed between seasons: low during the rainy season and high in the dry season. In the latter, the food niche overlap was asymmetric because C. nigrofasciata consumed several prey of P. aff. brevis, which reduced its food spectrum. The ecomorphological analysis suggests that C. nigrofasciatahas greater swimming capacity (greater relative length of caudal peduncle) than P. aff. brevis, which has greater maneuverability and tendency to inhabit lentic environments (greater relative depth of the body). Our results demonstrate that these species have similar trophic ecology and suggest a spatial segregation, given by morphological differences related to locomotion and occupation of habitat, favoring their coexistence.


2010 ◽  
Vol 16 (1) ◽  
pp. 36 ◽  
Author(s):  
A. J. Buckmaster ◽  
W. S. Osborne ◽  
N. Webb

Urban development can alter species composition and diversity within an area through biotic homogenization, the introduction of exotic species, and localized extinctions of native species. In this study we examined the composition and diversity of small terrestrial mammals within nature reserves surrounded by urban landscapes and compared this with previous surveys of these reserves and nearby non-urban reserves with similar vegetative and geomorphological characteristics. A combination of live trapping and indirect detection techniques was employed in eight reserves in the Australian Capital Territory and surrounding New South Wales to determine current species composition. Compared with previous studies and the non-urban reserves, the urban reserves appear to have lost two-thirds of their native terrestrial small mammal species in the past 26 years. Exotic species were present in all urban reserves, but were only associated with areas characterized by human-induced disturbance in non-urban reserves. Possible causes of this disparity in native species diversity between urban and non-urban reserves are discussed.


2017 ◽  
Vol 15 (2) ◽  
Author(s):  
Bruno E. Soares ◽  
Daniela C. O. Rosa ◽  
Nathália C. S. Silva ◽  
Miriam P. Albrecht ◽  
Érica P. Caramaschi

ABSTRACT Fishes of the order Gymnotiformes have high diversity of oral and head morphology, which suggests trophic specializations within each clade. The aim of this study was to describe resource use patterns by two fish species (Gymnorhamphichthys rondoni and Gymnotus coropinae) in the National Forest Saracá-Taquera, Oriximiná - Pará, analyzing microhabitat use, diet composition, feeding strategies, niche breadth and niche overlap. Stomach contents of 101 individuals (41 G. rondoni and 60 G. coropinae), sampled in 23 headwater streams were analyzed and volume of food items was quantified to characterize their feeding ecology. Gymnorhamphichthys rondoni was captured mainly on sandy bottoms, whereas G. coropinae in crevices. Both species had a zoobenthivorous diet and consumed predominantly Sediment/Detritus and Diptera larvae, but also included allochthonous prey in their diet. These species had high niche overlap, with small variations related to the higher consumption of Ceratopogonidae larvae by G. rondoni and of Chironomidae larvae by G. coropinae. Both species had a generalist feeding strategy, but G. coropinae had a broader niche breadth. Our results demonstrate that G. rondoni and G. coropinae occupy different microhabitats but rely on similar food resources.


1998 ◽  
Vol 76 (8) ◽  
pp. 1456-1471 ◽  
Author(s):  
John KB Ford ◽  
Graeme M Ellis ◽  
Lance G Barrett-Lennard ◽  
Alexandra B Morton ◽  
Rod S Palm ◽  
...  

Two forms of killer whale (Orcinus orca), resident and transient, occur sympatrically in coastal waters of British Columbia, Washington State, and southeastern Alaska. The two forms do not mix, and differ in seasonal distribution, social structure, and behaviour. These distinctions have been attributed to apparent differences in diet, although no comprehensive comparative analysis of the diets of the two forms had been undertaken. Here we present such an analysis, based on field observations of predation and on the stomach contents of stranded killer whales collected over a 20-year period. In total, 22 species of fish and 1 species of squid were documented in the diet of resident-type killer whales; 12 of these are previously unrecorded as prey of O. orca. Despite the diversity of fish species taken, resident whales have a clear preference for salmon prey. In field observations of feeding, 96% of fish taken were salmonids. Six species of salmonids were identified from prey fragments, with chinook salmon (Oncorhynchus tshawytscha) being the most common. The stomach contents of stranded residents also indicated a preference for chinook salmon. On rare occasions, resident whales were seen to harass marine mammals, but no kills were confirmed and no mammalian remains were found in the stomachs of stranded residents. Transient killer whales were observed to prey only on pinnipeds, cetaceans, and seabirds. Six mammal species were taken, with over half of observed attacks involving harbour seals (Phoca vitulina). Seabirds do not appear to represent a significant prey resource. This study thus reveals the existence of strikingly divergent prey preferences of resident and transient killer whales, which are reflected in distinctive foraging strategies and related sociobiological traits of these sympatric populations.


Biologia ◽  
2013 ◽  
Vol 68 (1) ◽  
Author(s):  
Zuzana Poláčiková

AbstractThis study deals with the species distribution and structure of mite communities living in the fur of small mammals. Mesostigmatic mites (Acarina: Mesostigmata) of several small mammal species were studied at several sites of Slovakia situated in the Podunajská nížna lowland. The aims deal with ecological evaluation of mesostigmatic mites and their small mammal hosts. The research was done from 2005 to 2007. Several small mammal species were caught at 16 sites in the research area. These represent 13 types of biotopes. On the captured small mammals we recorded 3,141 individuals of mesostigmatic mites (7 families and 22 species). The dominance and the diversity of the recorded mites were analysed. Mites being interpreted as the variable one were evaluated by cluster analysis and multifactor analysis (detrended correspondence analysis, principal components analysis, redundancy analysis). Small terrestrial mammals as hosts of mites represent “holders” of environmental factors, in the analysis they are being evaluated as explanatory variable mainly. They transform direct impact of the environment and for that reason the ecological evaluation of mites is specific comparing to other taxonomical and ecological groups of animals.


Paleobiology ◽  
2011 ◽  
Vol 37 (4) ◽  
pp. 577-586 ◽  
Author(s):  
Julia Fritz ◽  
Jürgen Hummel ◽  
Ellen Kienzle ◽  
Oliver Wings ◽  
W. Jürgen Streich ◽  
...  

Particle size reduction is a primary means of improving efficiency in herbivores. The mode of food particle size reduction is one of the main differences between herbivorous birds (gizzard) and mammals (teeth). For a quantitative comparison of the efficiency of food comminution, we investigated mean fecal particle sizes (MPS) in 14 herbivorous bird species and compared these with a data set of 111 non-ruminant herbivorous mammal species. In general MPS increased with body mass, but there was no significant difference between birds and mammals, suggesting a comparable efficiency of food processing by gizzards and chewing teeth. The results lead to the intriguing question of why gizzard systems have evolved comparatively rarely among amniote herbivores. Advantages linked to one of the two food comminution systems must, however, be sought in different effects other than size reduction itself. In paleoecological scenarios, the evolution of “dental batteries,” for example in ornithopod dinosaurs, should be considered an advantage compared to absence of mastication, but not compared to gizzard-based herbivory.


2021 ◽  
Author(s):  
Benoit Gauzens ◽  
Benjamin Rosenbaum ◽  
Gregor Kalinkat ◽  
Thomas Boy ◽  
Malte Jochum ◽  
...  

Abstract Adaptative foraging behavior should promote species coexistence and biodiversity under climate change as predators are expected to maximize their energy intake, according to principles of optimal foraging theory. We test these assumptions using a dataset comprising 22,185 stomach contents of fish species across functional groups, feeding strategies, and prey availability in the environment over 12 years. Our results show that foraging shifts from trait-dependent prey selectivity to density dependence in warmer and more productive environments. This behavioral change leads to lower consumption efficiency as species shift away from their optimal trophic niche, undermining species persistence and biodiversity. By integrating this adaptive foraging behavior into dynamic models, our study reveals higher risk profiles for ecosystems under global warming.


Author(s):  
Fred W. Scott ◽  
Andrew J. Hebda

The latest taxonomic, distributional, habitat and conservation status information is presented for a total of 91 species of marine and terrestrial mammals presently or historically known from Nova Scotia. Four of them are extirpated and one is extinct. Of the 86 remaining species 51 are terrestrial (46 native, 5 introduced). The terrestrial mammals include 9 species of Insectivora, 6 (+ one tentative) of Chiroptera, one Primate, 12 Carnivora, 1 Perrissodactyla, 3 Artiodactyla, 19 Rodentia and 1 Lagomorpha. Native species include Boreal, Transition Zone and Austral elements, the result of Nova Scotia’s mid-latitude position on the continental coast.The 32 recorded marine species include 6 Carnivora (5 seals, walrus) and 26 Cetacea: Delphinidae (10 species), Phocoenidae (1), Monodontidae (1), Kogiidae (2), Physeteridae (1), Ziphiidae (4), Eschrichtiidae (1, extirpated), Balaenopteridae (5) and Balaenidae (1).Since 1971 four small mammal species (Sorex gaspensis, S. dispar, Glaucomys volans and Microtus chrotorrhinus) have been added to the provincial fauna, as a result of the first systematic and intensive sampling ever done in Nova Scotia. All are disjunct and three of them are restricted to forested talus habitats in the Cobequid Mts. or the Cape Breton Highlands. With the two disjunct species already known (Sorex arcticus maritimensis and Peromyscus leucopus caudatus), there are 6 disjunct mammals in the province, comprising 14.3 % of native non-volant terrestrial mammals, 33 % of insectivores and 18.8 % of native rodents. Two of them (Sorex gaspensis and Microtus chrotorrhinus) occur only on Cape Breton Island. No other area of similar size north of Mexico has a comparable proportion of disjunct mammals.Cape Breton Island historically has had a depauperate mammal fauna, lacking 8 species that were present on the adjacent mainland. The building of the connecting Canso Causeway in 1953-55 had a major zoogeographic impact, as it caused the western third of the strait to freeze over in winter and allowed the invasion and establishment of four large mammal species (Canis latrans, Procyon lotor, Mephitis mephitis and Lynx rufus).Le document présente l’information la plus récente sur la taxonomie, la répartition, l’habitat et la situation de 91 espèces de mammifères marins et terrestres qui vivent actuellement ou ont déjà vécu en Nouvelle-Écosse. Quatre d’entre elles ont disparu et une est éteinte. Sur les 86 autres espèces, 51 sont terrestres (46 espèces indigènes et 5 espèces introduites). Les mammifères terrestres comprennent 9 Insectivora, 6 (+ une espèce provisoire) Chiroptera, un Primate, 12 Carnivora, un Perrissodactyla, 3 Artiodactyla, 19 Rodentia et un Lagomorpha. La Nouvelle-Écosse étant située à une latitude moyenne sur la côte continentale, les espèces indigènes qui y vivent sont des éléments de la zone boréale, de la zone de transition et de la zone australe.Parmi les 32 espèces marines signalées, on compte 6 Carnivora important a (5 phoques et le morse) et 26 Cetacea: Delphinidae (10 espèces), Phocoenidae (1), Monodontidae (1), Kogiidae (2), Physeteridae (1), Ziphiidae (4), Eschrichtiidae (1, disparue), Balaenopteridae (5) et Balaenidae (1).Depuis 1971, à la suite du premier échantillonnage systématique et intensif mené en Nouvelle-Écosse, quatre espèces de petits mammifères (Sorex gaspensis, S. dispar, Glaucomys volans et Microtus chrotorrhinus) se sont ajoutées aux espèces fauniques de la province. Ce sont toutes des espèces disjointes, et trois d’entre elles sont confinées aux talus d’éboulis boisés des monts Cobequid ou des hautes-terres du Cap-Breton. Si on inclut les deux espèces disjointes déjà connues (Sorex arcticus maritimensis et Peromyscus leucopus caudatus), il existe 6 espèces disjointes de mammifères dans la province, qui représentent 14,3 % des mammifères terrestres indigènes qui ne volent pas, 33 % des Insectivores et 18,8 % des Rongeurs indigènes. Deux d’entre elles (Sorex gaspensis et Microtus chrotorrhinus) ne sont présentes que dans l’île du Cap-Breton. Au nord du Mexique, aucune autre région de taille semblable n’a une telle proportion d’espèces disjointes de mammifères.Dans le passé, l’île du Cap-Breton renfermait relativement peu de mammifères : on y trouvait 8 espèces de moins que dans la partie continentale de la Nouvelle-Écosse. La construction de la levée de Canso en 1953-1955 a eu un impact important zoogéographique du fait que, depuis, le tiers ouest du détroit gèle durant l’hiver, ce qui a permis à quatre espèces de gros mammifères (Canis latrans, Procyon lotor, Mephitis mephitis et Lynx rufus) de gagner l’île et de s’y établir.


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