Understorey structure and refuges from predators influence habitat use by a small ungulate, the Indian chevrotain (Moschiola indica) in Western Ghats, India

The availability of refuges from predators and high quality food are thought to determine habitat use in small ungulates. We tested this hypothesis on habitat use by the Indian chevrotain in a tropical rainforest in the Western Ghats, using pellet-groups to infer habitat use. Between December 2009 and April 2010, we sampled 204 grids of 50 m × 50 m with four spatial replicates in each, using occupancy framework. We quantified refuges such as fallen logs and boulders, understorey complexity, and noted the presence of fruiting trees in the grid. Detection probability, p, of pellet-groups was estimated at 0.61. The naive estimate of occupancy was 0.52, which increased to 0.73 when p was accounted for. Out of eight candidate models compared using AIC_C, the one with the number of refuges and understorey complexity was the best model. Both covariates had non-zero positive slopes. Fruiting trees occurred very infrequently and did not influence habitat use, perhaps because the chevrotain fed more on buds, shoots and young leaves during the dry period covered by this study. The strong influence of understorey complexity on habitat use was perhaps also due to the abundance of these food items. These results highlight the need to control human use that adversely impacts the availability of refuges and understorey complexity such as removal of fallen logs and rattans. This study also demonstrates the application of the occupancy approach in the study of small and elusive ungulates.     

Dry season habitat use by critically endangered white-shouldered ibis in northern Cambodia

We present the first scientific study of white-shouldered ibis Pseudibis davisoni habitat preferences in dry dipterocarp forest. Foraging sites included seasonal pools, forest understorey grasslands and fallow rice fields, with terrestrial sites used more following rainfall. Habitat and anthropogenic effects in logistic models of foraging site selection were examined by multimodel inference and model averaging. White-shouldered ibis preferred pools with greater cover of short vegetation (<25 cm) and less of the boundary enclosed, and forest sites with greater cover of bare substrate and lower people encounter rate. At forest sites, livestock density was positively related to bare substrate extent and thus may improve suitability for foraging ibis. At pools, livestock removed tall vegetation between the early and late dry season indicating their importance in opening up foraging habitats after wet season growth. However, by the late dry season, pools with greater livestock density had less short vegetation, the habitat favoured by ibis. Conservation strategies for white-shouldered ibis must consider a range of habitats, not just seasonal wetlands, and should incorporate extensive grazing and associated burning practises of local communities. Further understanding of the effects of these practices on vegetation, prey abundance and prey availability are therefore needed for effective conservation of this species. This will also develop our understanding of potentially beneficial anthropogenic influences in tropical environments.     

Determinants of habitat occupancy and spatial segregation of primates in the central Western Ghats,India

Primates - Primates are among the globally imperiled fauna requiring urgent conservation interventions to protect their habitat. Information on species distribution and factors influencing it are...     

Sexual segregation and density-related changes in habitat use in male and female Red deer (Cerrus elaphus)

Sex differences in diet and habitat use in Red deer occur in several areas of Scotland. In some cases, they are a consequence of differences in the altjtude levels used but, on Rhum, both sexes use the same levels, concentrating in different areas of the same plant communities. Segregation between the sexes is most pronounced for animals feeding on short grasslands and increases in winter and at high population density. These results support the hypothesis that stags are less tolerant of low plant biomasses than hinds and can be excluded from mutually preferred communities by indirect competition     

Assemblage structure of stream fishes in the Western Ghats (India)

Macro and microhabitat analyses were applied to characterise the fish assemblage structure in 10 streams of the Western Ghat mountains of Peninsular India. Macrohabitat features, such as channel gradient, stream depth, stream width, riparian cover, instream cover, habitat types and substrates, were used. Microhabitat requirements of the abundant cyprinids (35 species) were also analysed. Macrohabitat assessment indicated that a high habitat diversity was associated with a high species diversity, and that habitat volume was a major determining factor for species diversity and abundance. In all streams, cyprinids were the dominant group in the assemblage and almost all cyprinids were confined to pools with a varied habitat diversity. Riffle dwelling species included ancient forms such as Glyptothorax madraspatnum, G. trewasae and Homaloptera santhamparaiensis. Suitable microhabitats for dominant cyprinid species were pools and riffle edges. Big-sized barbs and mahseers such as Hypselobarbus dobsoni, H. curmuca, H. dubius, Labeo calbasu, Puntius sarana, Tor khudree and Tor khudree malabaricus were confined to deep pools with a large area. Smaller Puntius species like P. fasciatus, P. melanampyx, P. narayani, P. sophore, P. ticto and P. vittatus lived in shallow backwater pools and pools with low flow. Species like P. arulius tambiraparniei, P. amphibius, P. bimaculatus and P. filamentosus were found towards shallow pools with moderate flow. Surface-dwelling species such as Danio aequipinnatus, Rasbora daniconius, Salmostoma spp. and Barilius spp. preferred deepwater habitats with high flow. Habitat-based multivariate analysis revealed four guilds: surface dwellers, column dwellers, generalized bottom dwellers and specialized bottom dwellers.     

Land use and forest habitat distribution in the hinterland of(r)a large city

The cumulative effect of many local forest disturbances can be estimated from an analysis of forest distribution at the scale of the entire landscape. To gauge the regional impact of forest clearance and regeneration, a history of forest cover was compiled for the twentieth century in the hinterland of a large city (Wilmington, Delaware, U.S.A.). Forest distribution and character were described by point sampling of historical aerial photographs. Environmental features were measured on visits to sample points in the field. Regional forest coverage has grown from c . 5% in 1890 to 22% in 1990. Most modern stands are <60 years old; only 2.5% of the modern landscape is in forest more than 100 years old. Since 1890, patterns of clearance and regeneration have caused a proportional shift in forest cover from uplands to lowlands and flood plains. Older stands are found on rock fields and steep slopes, indicating abandonment from agriculture according to the quality of local sites. Residential development has been concentrated in uplands, precluding regeneration of forest in that landscape position. In general, land use turnover reflects the character of the local site; there is no evidence of region-wide gradients of regeneration or clearance. Modern forest is concentrated along steep-sided stream valleys and away from roads. The great majority of forest lies within 50 m of a forest margin placing it in the microclimatic and vegetational edge zone. Although most forest is within 200 m of a residence, pedestrian traffic appears to have had only a minor impact in the biological community. By contrast, widespread species impoverish- ment is suggested by the overwhelming youthfulness of modern forest and the low degree of connectedness of forest within the landscape. Management for biological conservation should focus on protection of remnant primary forest, rather than relying on succession to restock secondary stands.     

Age and season determine European rabbit habitat use in Mediterranean ecosystems

Knowledge about the factors determining habitat use is especially interesting for herbivores living under seasonal climates as they have to deal with food shortage during the drought season. In this context, different-aged individuals are expected to respond differently to seasonal variations because nutritional requirements and predation risk can vary with age. We investigated adult and juvenile European rabbit (Oryctolagus cuniculus) habitat use in a Mediterranean ecosystem of central Spain, during spring, summer and winter. Relationships between adult and juvenile rabbit pellet abundances and 11 environmental variables related to food availability and refuge density were analysed by means of multiple regression, and evaluated using information theory to identify the set of models best supported by the data. Density of warren entrances was the more constant predictor of habitat use for juvenile rabbits in all the seasons. Herbaceous vegetation volume had a negative influence and was the strongest predictor for adult rabbit habitat use in spring and winter. In summer, green vegetation cover became the strongest positive habitat use predictor. These results suggest that adults prefer to forage in low volume swards ensuring a wide sensory range for the detection of approaching predators. However, the arrival of summer and its associated food depletion forces them to shift toward more open productive areas where green vegetation persists, but at the expense of higher predation risk. Seasonal variation induces minor changes in juvenile habitat use due to their strong dependence on warrens. Thus, our results show that rabbit habitat use is influenced by animal age and seasonal variations in resources.     

The shrubs of the Western Ghats (South India): floristics and status

Abstract. This study examines the understorey shrub community in a wet evergreen forest of South India. The shrub community in the evergreen forests of the Western Ghats, Eastern Ghats, Sri Lanka, South-east Asia, Neotropics, Africa and Madagascar are compared. The shrub community is richer in the Old World Tropics as compared to the Neotropics. The common families in the Old World Tropics are: Rubiaceae, Acanthaceae, Euphorbiaceae, Myrsinaceae and Annonaceae. The number of families constituting the understorey shrub community falls from forty-six (Western Ghats) to thirteen (Central Amazon). The study concludes that the evergreen forests in the Western Ghats probably have the richest understorey shrub community.
Résumé. L'étude concerne la communauté d'arbustes de sous-bois d'une forêt sempervirente du Sud de l'lnde. Les communautés d'arbustes dans les forèts sempervirentes des Ghâts Occidentaux, des Ghâts Orientaux, du Sri Lanka, du Sud-Est Asie, des Néotropiques, de l'Afrique et de Madagascar sont comparées. La communauté d'arbustes est plus riche dans le Vieux Monde Tropical que dans les Néotropiques. Les families communes dans le Vieux Monde Tropical sont; Rubiaceae, Acanthaceae, Euphorbiaceae, Myrsinaceae et Annonaceae. Le nombre de families constituant la communauté d'arbustes de sous-bois varie de 46 (Ghâts Occidentaux) à 13 (Amazonie Centrale). L'étude conclue que les forêts sempervierentes des Ghàts Occidentaux ont probablement la plus riche communauté d'arbustes de sois-bois.
Mots clés. Communauté d'arbustes de sous-bois, forêts sempervirentes, Ghâts Occidentaux, endémisme, Inde.     

History, distribution, status and habitat requirements of the Harvest mouse (Micromys minutus) in Britain

This paper reviews the past known history of the Harvest mouse and presents the results of a survey of the distribution and status of the animal in Britain. Data are included which demonstrate the wide variety of habitats colonized by the Harvest mouse and the diversity of monocotyledonous plants that can be utilized for nest building. The survey has shown that there is no evidence of a decline in the distribution or abundance of this animal in Britain during the last century, and that the sparsity of earlier records was probably due to the lack of competent recorders.     

Correction to: Determinants of habitat occupancy and spatial segregation of primates in the central Western Ghats,India

Primates - In the original publication of the article, the second author’s name was wrongly published. The correct name is given in this correction.     

Long-term density-dependent changes in habitat selection in red deer (Cervus elaphus)

Understanding how habitat selection changes with population density is a key concept in population regulation, community composition and managing impacts on biodiversity and ecosystem services. At low density, it is expected that individuals select habitats in terms of their preference, but as population density increases, the availability of resources per individual declines on preferred habitats, leading to competition which forces some individuals to exploit less preferred habitats. Using spatial information of Scottish red deer (Cervus elaphus) winter counts, carried out in 110 areas across Scotland between 1961 and 2004 (a total of 1,206,495 deer observations), we showed how winter habitat niche breadth in red deer has widened with increasing population density. Heather moorland and montane habitats were most and least preferred for deer, respectively. Increasing density favoured the selection of grassland, to the detriment of the selection of heather moorland. The selection of heather and grassland decreased when temperature increased, while the selection of montane and peatland habitats increased. These findings are important for understanding how habitat use, density and population are likely to be affected by weather, and allow us to predict habitat impacts by large mammal herbivory and climate.     

Aspects of breeding biology of chital (Axis axis) and sambar (Rusa unicolor) in the Western Ghats

Antler cycles are convenient external signs indicating internal changes in reproductive status of male deer. Antler phenology of chital (Axis axis) and sambar (Rusa unicolor) were studied in a deciduous habitat of Mudumalai Tiger Reserve, Western Ghats, using vehicle transects for 2 successive years. Apparent breeding seasonality occurred with the majority of adult stags in hard antlers from May to mid October in chital (>87 %), and October to May in sambar (>68 %). Adult hard antler in chital correlated with mean group size, while sambar showed a weak correlation between adult hard antler and group size. Chitals prefer forming large groups at forest edges and open habitats while sambars prefer dense vegetation cover. Adult hard antlers in chital and sambar showed a weak relation to fawning since most adult females were in oestrus during the peak rutting season. Adult hard antlers in chital associated positively with rainfall and day length while sambar responded weakly to rainfall. We conclude that environmental variables determined species-specific mating strategies in the two deer species.     

Behavioural responses of lion-tailed macaques (Macaca silenus) to a changing habitat in a tropical rain forest fragment in the Western Ghats, India.

This study reports critical changes in the behaviour patterns of lion-tailed macaques (Macaca silenus) inhabiting a continuously changing and deteriorating rain forest fragment in the Western Ghats, India. The study area, a privately owned rain forest patch in a tea/coffee garden called Puthuthotam, has suffered two massive selective logging episodes. Over the years, the native rain forest trees have been largely replaced by non-native/pioneer species resulting in loss of canopy contiguity and significant changes in other vegetation parameters. The almost wholly arboreal lion-tailed macaque now spends a considerable amount of time on the ground in this area. The species has also experienced a major shift in its diet, ranging patterns and other activities.     

Group size, sex and age composition of chital (Axis axis) and sambar (Rusa unicolor) in a deciduous habitat of Western Ghats

Knowledge of the social structure of a population is important for a range of fundamental and applied purposes. Group characteristics and population structure of chital (Axis axis) and sambar (Rusa unicolor) were studied in a deciduous habitat of Mudumalai Tiger Reserve, Western Ghats, India, during 2008-2009. Vehicle transects were monitored monthly to gather information on group-size and age-sex composition of chital and sambar. The average mean group size and crowding for chital and sambar was 13.1 ± 0.5 (n = 1020), 3.6 ± 0.2 (n = 377) and 33.3, 11.0 respectively. The average adult male:adult female:fawn ratio was 63.4:100:22.3 (n = 9391) and 43.9:100:23.7 (n = 1023) in chital and sambar respectively. The mean group size of chital and sambar varied significantly between seasons (Kruskal-Wallis test, p = <0.001). Peak fawning season was observed from February to May for chital and May to August for sambar. Group's sex-age composition influenced group formation in both species between seasons at different level. Adult male and fawn were the important predicting variables of change in group size. Skewed female sex ratio was probably due to selective male predation by large predators. Although fawning occurred throughout the year, both species showed seasonality in fawning. The above mentioned patterns differed between species depending upon their ecological adaptation in foraging strategies and habitat preference.     

Migratory strategies, fawn recruitment, and winter habitat use by urban and rural mule deer (Odocoileus hemionus)

We examined the migratory strategies of mule deer (Odocoileus hemionus) using adjacent urban and rural winter ranges in northern Utah in relation to deer demography and patterns of habitat use. Urban deer were more likely to be migratory than rural deer, even though migratory animals from the two herds intermixed on a common, high-elevation summer range. Urban deer exhibited lower fawn recruitment than rural deer; but within each herd, demographic characteristics of migratory and nonmigratory animals suggested that game theory explained the ratios of deer adopting each behavior. Estimates of animal numbers and available habitat did not reveal clearly whether deer densities differed on the two winter ranges. However, patterns of habitat use by urban deer were so clustered around areas of concealment vegetation that animals probably experienced higher local densities than rural animals. In addition, the clustered patterns of habitat use by urban deer resulted in incomplete use of available forage. This may have contributed to the relatively poor fawn recruitment by urban deer, a phenomenon that appeared to be perpetuated by their strong fidelity to winter range.     

Effects of lactation on feeding behaviour and habitat use in wild Red deer hinds

In many mammals, the energetic costs of lactation double a female's daily energy requirements on her activity budgets, food choice and ranging behaviour–but the effects of lactation have rarely been documented. In this paper, the ecological consequences of lactation in free-ranging Red deer ( Cervus elaphus ) hinds on the lsle of Rhum is examined by comparing the feeding behaviour, habitat use and ranging behaviour of hinds that were supporting calves (milk hinds) with hinds that did not have calves (yeld hinds). In summer, milk hinds graze for approximately two hours longer per day then yeld hinds. This difference has disappeared by the latter half of the winter, when the grazing budgets of milk and yeld hinds are similar. Both in summer and winter milk hinds spend more time grazing on the most strongly selected plant communities (short, herb-rich greens) where standing crops are low but food quality is comparatively high. Inter-year variation in habitat use by milk hinds is also closely related to variation in rainfall—while this is not the case among yeld hinds. Both in summer and winter, yeld hinds range more widely than milk hinds.