Protein limitation has been considered a key factor in hypotheses on the evolution of life history and animal communities, suggesting that animals should prioritize protein in their food choice. This contrasts with the limited support that food selection studies have provided for such a priority in nonhuman primates, particularly for folivores. Here, we suggest that this discrepancy can be resolved if folivores only need to select for high protein leaves when average protein concentration in the habitat is low. To test the prediction, we applied meta-analyses to analyze published and unpublished results of food selection for protein and fiber concentrations from 24 studies (some with multiple species) of folivorous primates. To counter potential methodological flaws, we differentiated between methods analyzing total nitrogen and soluble protein concentrations. We used a meta-analysis to test for the effect of protein on food selection by primates and found a significant effect of soluble protein concentrations, but a non-significant effect for total nitrogen. Furthermore, selection for soluble protein was reinforced in forests where protein was less available. Selection for low fiber content was significant but unrelated to the fiber concentrations in representative leaf samples of a given forest. There was no relationship (either negative or positive) between the concentration of protein and fiber in the food or in representative samples of leaves. Overall our study suggests that protein selection is influenced by the protein availability in the environment, explaining the sometimes contradictory results in previous studies on protein selection. Am. J. Primatol. 79:e22550, 2017. © 2016 Wiley Periodicals, Inc.

Th e decisions that animals must make to achieve a balance between quantity and quality of resources become more diffi cult when their habitats are patchy and diff er greatly in quality across space and time. Koalas are a prime subject to study this problem because they have a specialised diet of eucalypt leaves and need to balance nutrient and water intake against toxins in the leaves, all of which can change with soil type and climate. Koalas are nocturnal and spend most of the day resting and therefore choose trees for reasons other than feeding, particularly for thermoregulation. We GPS-tracked 40 koalas over 3 yr to determine their shift in tree selection between day and night, and in relation to daily maximum temperature, in a patchy rural landscape in north-western NSW, Australia. Th e species, degree of shelter, diameter, height and elevation of each visited tree were recorded. We used generalised linear mixed eff ects models to compare tree use between day and night and maximum daily temperature. Koalas used more feed-trees during the night, and more shelter-trees during the day. Th ey also selected taller trees with more shelter in the day compared with night. As daytime temperatures rose, koalas increasingly selected taller trees at lower elevations. Our results demonstrate that koalas need taller trees, and non-feed species with shadier/denser foliage, to provide shelter from heat. Th is highlights the need both for the retention of taller, mature trees, such as remnant paddock trees, and the planting of both food and shelter trees to increase habitat area and connectivity across the landscape for arboreal species. Retaining and planting trees that provide optimum habitat will help arboreal folivores cope with the more frequent droughts and heatwaves expected with climate change.

Koalas Phascolarctos cinereus are specialised, folivorous arboreal marsupials that do not go into torpor, fly, or shelter in hollows, and lack any ready means of avoiding weather extremes. This makes them valuable candidates to study impacts of climate change. This paper draws on our field study of koalas in Gunnedah in northwest New South Wales (NSW), to not only examine this proposition, but to progress to the next step of considering how we, as koala managers, can adapt our strategies to help the koala population cope with predicted climatic changes. The koala already faces a powerful set of threats, such as loss of habitat and fragmentation of what remains, disease, fire, and the impact of losses from dogs and vehicles. Climate change will compound these issues, accelerate adverse changes and demand a reappraisal of our approach to koala management. The koala is not unique in this predicament, but it is symbolic of the impact that can be expected on a wide range of species.