Influence of soil type on the properties of termite mound nests in Southern India

Termite mounds are conspicuous features in many tropical ecosystems. Their shape and soil physicochemical properties have been suggested to result from the termites ecological need to control the temperature and humidity within their nests and protect themselves from predators. This study aimed to determine the influence of the parent soil properties on the shape and soil physical and chemical properties of termite mounds. Termite mounds built by the fungus-growing termite species Odontotermes obesus were compared in two forests with different soil properties (Ferralsol or Luvisol) in Southern India. Our findings confirm that soil properties influence the physicochemical characteristics of mound material and may affect the shape, but these impacts are mostly independent of the size of the mounds (i.e., the age of the colonies). Mound walls were more enriched in clay and impoverished in C and N in the Luvisol than the Ferralsol. However, their shape was more complex in the Ferralsol than the Luvisol, suggesting a possible link between the clay content in soil and the shape of termite mounds. The results also suggest that clay becomes enriched in O. obesus mound walls through a more passive process rather than solely by particle selection, and that termite mound shape results from the soil properties rather than the ecological needs of termites. In conclusion, although ecologists have mainly focused upon the influence of termite ecological needs on their nest properties, this study highlights the need for a better understanding about the role of the soil pedological properties and, as a consequence, how these properties drive the establishment and survival of termites in tropical ecosystems. (C) 2015 Elsevier B.V. All rights reserved.

Fruit Trait Preference in Rhesus Macaques (Macaca mulatta) and its Implications for Seed Dispersal

Primates constitute 25-40 % of the frugivore biomass of tropical forests. Primate fruit preference, as a determinant of seed dispersal, can therefore have a significant impact on these ecosystems. Although the traits of fruits included in primate diets have been described, fruit trait preference has been less studied with respect to fruit availability. We examined fruit trait preference and its implications for seed dispersal in the rhesus macaque (Macaca mulatta), a dietarily flexible species and important seed disperser, at the Buxa Tiger Reserve, India. Over a year, we monitored the phenology of selected trees in the study area, observed the feeding behavior of rhesus macaques using scans and focal animal sampling, and documented morphological traits of the fruits/seeds consumed. Using generalized linear modeling, we found that the kind of edible tissue was the chief determinant of fruit consumption, with M. mulatta feeding primarily on fruits with juicy-soft pulp and acting as seed predators for those with no discernible pulp. Overall, the preferred traits were external covers that could be easily pierced by a fingernail, medium to large seeds, true stone-like seeds, and juicy-soft edible tissue, thereby implying that fruit taxa with these traits had a higher probability of being dispersed. Macaques were more selective during the high fruit availability period than the low fruit availability period, preferentially feeding on soft-skinned fruits with juicy-soft pulp. We suggest that further studies be conducted across habitats and time to understand the consistency of interactions between primates and fruits with specific traits to determine the degree of selective pressure (if any) that is exerted by primates on fruit traits.

How much Dillenia indica seed predation occurs from Asian elephant dung?

Elephants are thought to be effective seed dispersers, but research on whether elephant dung effectively protects seeds from seed predation is lacking. Quantifying rates of seed predation from elephant dung will facilitate comparisons between elephants and alternative dispersers, helping us understand the functional role of megaherbivores in ecosystems. We conducted an experiment to quantify the predation of Dillenia indica seeds from elephant dung in Buxa Reserve, India from December 2012 to April 2013. Using dung boluses from the same dung pile, we compared the number of seeds in boluses that are a) opened immediately upon detection (control boluses), b) made available only to small seed predators (<= 3 mm wide) for 1-4 months, and c) made available to all seed predators and secondary dispersers for 1-4 months. Using a model built on this experiment, we estimated that seed predation by small seed predators (most likely ants and termites) destroys between 82.9% and 96.4% of seeds in elephant dung between the time of defecation and the median germination date for D. indica. Exposure to larger seed predators and secondary dispersers did not lead to a significant additional reduction in the number of seeds per dung bolus. Our findings suggest that post-dispersal seed predation by small insects (<3 mm) substantially reduces but does not eliminate the success of elephants as dispersers of D. indica in a tropical moist forest habitat. (C) 2015 Elsevier Masson SAS. All rights reserved.

Wild Ungulate Decision-Making and the Role of Tiny Refuges in Human-Dominated Landscapes

Wildlife conservation in human-dominated landscapes requires that we understand how animals, when making habitat-use decisions, obtain diverse and dynamically occurring resources while avoiding risks, induced by both natural predators and anthropogenic threats. Little is known about the underlying processes that enable wild animals to persist in densely populated human-dominated landscapes, particularly in developing countries. In a complex, semi-arid, fragmented, human-dominated agricultural landscape, we analyzed the habitat-use of blackbuck, a large herbivore endemic to the Indian sub-continent. We hypothesized that blackbuck would show flexible habitat-use behaviour and be risk averse when resource quality in the landscape is high, and less sensitive to risk otherwise. Overall, blackbuck appeared to be strongly influenced by human activity and they offset risks by using small protected patches (similar to 3 km(2)) when they could afford to do so. Blackbuck habitat use varied dynamically corresponding with seasonally-changing levels of resources and risks, with protected habitats registering maximum use. The findings show that human activities can strongly influence and perhaps limit ungulate habitat-use and behaviour, but spatial heterogeneity in risk, particularly the presence of refuges, can allow ungulates to persist in landscapes with high human and livestock densities.