Foraging behaviour of two rodent species inhabiting a kopje (rocky outcrop) in Tsavo West National Park, Kenya

We employed patch use theory to evaluate how several environmental factors influence the foraging behaviour of two rodent species: Grammomys dolichurus and Acomys cahirinus. Foraging efficiency was determined by measuring the remaining food in artificial food patches (giving-up densities: GUDs) from two experiments. In the first experiment, we placed patches in different microhabitat types (cover vs open) and at varying distances from cover. This experiment was conducted during three moon stages (waxing, full, waning). We found that the rodents had higher GUDs (lower foraging efficiency) in the open microhabitat. The distance from nearest shelter had a marginally significant positive effect on GUDs. GUDs were higher in both microhabitat types during the waxing and full phases, but decreased sharply once the moon began to rise after sunset. These results are likely due to higher predation risk away from cover and in more illuminated environments. In the second experiment, we examined mouse responses to seeds impregnated with plant toxins. Seeds impregnated with oxalic acid were avoided by the rodents, while seeds soaked in tannic acid did not differ significantly from control seeds. Our results highlight important ecological factors affecting the foraging behaviour of these rodents.

A family-sized greenhouse for a remote mountain region of Nepal

Food security is a significant issue in the remote, high altitude areas of Nepal. Malnutrition is common because the harsh climate restricts production and access to fresh food. Humla is a province in north-west Nepal where the severe weather conditions and limited arable land restrict the growing season of vegetables to only 4-5 months a year. Passive solar greenhouses are a technology that can be used to extend the growing period of vegetables. For the greenhouse to be effective in Humla, the design must be appropriate to the climatic conditions, available resources and the social requirements of the community. This paper describes the design and evaluation of a family-sized solar greenhouse proposed for Humla. Three solar greenhouses built in other high altitude areas have initially been reviewed to see what techniques might be replicated in Humla. The thermal performance of the proposed family-sized greenhouse has been predicted using the solar simulation software, TRNSYS, and compared against an existing design in the area. The proposed design was found to be superior and average night-time temperatures in the coldest month were predicted to be approximately 7°C higher. Overheating was controlled in the hottest month by shading and natural ventilation.

Predicting avian distributions to evaluate spatiotemporal overlap with locust control operations in eastern Australia.

Locusts and grasshoppers cause considerable economic damage to agriculture worldwide. The Australian Plague Locust Commission uses multiple pesticides to control locusts in eastern Australia. Avian exposure to agricultural pesticides is of conservation concern, especially in the case of rare and threatened species. The aim of this study was to evaluate the probability of pesticide exposure of native avian species during operational locust control based on knowledge of species occurrence in areas and times of application. Using presence-absence data provided by the Birds Australia Atlas for 1998 to 2002, we developed a series of generalized linear models to predict avian occurrences on a monthly basis in 0.5 degrees grid cells for 280 species over 2 million km2 in eastern Australia. We constructed species-specific models relating occupancy patterns to survey date and location, rainfall, and derived habitat preference. Model complexity depended on the number of observations available. Model output was the probability of occurrence for each species at times and locations of past locust control operations within the 5-year study period. Given the high spatiotemporal variability of locust control events, the variability in predicted bird species presence was high, with 108 of the total 280 species being included at least once in the top 20 predicted species for individual space-time events. The models were evaluated using field surveys collected between 2000 and 2005, at sites with and without locust outbreaks. Model strength varied among species. Some species were under- or over-predicted as times and locations of interest typically did not correspond to those in the prediction data set and certain species were likely attracted to locusts as a food source. Field surveys demonstrated the utility of the spatially explicit species lists derived from the models but also identified the presence of a number of previously unanticipated species. These results also emphasize the need for special consideration of rare and threatened species that are poorly predicted by presence-absence models. This modeling exercise was a useful a priori approach in species risk assessments to identify species present at times and locations of locust control applications, and to discover gaps in our knowledge and need for further focused data collection.

Mountain barriers and river conduits: phylogeographical structure in a large, mobile lizard (Varanidae: Varanus varius) from eastern Australia

Aim: Across eastern Australia, mountain ranges (the Great Dividing Range) and river catchments (the Murray-Darling Basin) are likely to have shaped the phylogeographical structure of many species. We address how such processes have influenced the phylogeography of the lace monitor, Varanus varius, a large mobile lizard. Location: Eastern and south-eastern Australia. Methods: Phylogeographical hypotheses were tested using up to 90 museum and field-collected samples from across the entire species' range; a 671-bp region of the mtDNA gene ND4 was sequenced and all individuals were genotyped (eight microsatellite loci). Results: Maximum-likelihood analysis of sequence data revealed three geographically separate clades, with divergences estimated to have occurred during the Pleistocene. The south-eastern clade showed an expansion pattern from northern refugia and dispersal appears to have occurred along the Murray-Darling river system. Microsatellite analyses support mtDNA clades but indicate secondary contact in the Hunter Valley, New South Wales. Main conclusions: Our results indicate that phylogeographical structure and contemporary gene flow in Varanus varius is shaped by dispersal capacity, geographical barriers and the presence of ancient river corridors. Indeed, only the most significant geological (McPherson Range) and habitat barriers (Burdekin Gap) appear to limit gene flow in this species. The expansion of the clade on the western side of the Great Dividing Range suggests that ancient riparian corridors have facilitated extensive gene flow. Our study highlights the importance of understanding a species' ecological dynamics when examining broad-scale evolutionary patterns.