Chimpanzees Use Least-Cost Routes to Out-of-Sight Goals.

While the ability of naturally ranging animals to recall the location of food resources and use straight-line routes between them has been demonstrated in several studies [1, 2], it is not known whether animals can use knowledge of their landscape to walk least-cost routes [3]. This ability is likely to be particularly important for animals living in highly variable energy landscapes, where movement costs are exacerbated [4, 5]. Here, we used least-cost modeling, which determines the most efficient route assuming full knowledge of the environment, to investigate whether chimpanzees (Pan troglodytes) living in a rugged, montane environment walk least-cost routes to out-of-sight goals. We compared the "costs" and geometry of observed movements with predicted least-cost routes and local knowledge (agent-based) and straight-line null models. The least-cost model performed better than the local knowledge and straight-line models across all parameters, and linear mixed modeling showed a strong relationship between the cost of observed chimpanzee travel and least-cost routes. Our study provides the first example of the ability to take least-cost routes to out-of-sight goals by chimpanzees and suggests they have spatial memory of their home range landscape. This ability may be a key trait that has enabled chimpanzees to maintain their energy balance in a low-resource environment. Our findings provide a further example of how the advanced cognitive complexity of hominins may have facilitated their adaptation to a variety of environmental conditions and lead us to hypothesize that landscape complexity may play a role in shaping cognition.

Chimpanzee ranging responses to fruit availability in a high-elevation environment.

Most primates experience seasonal fluctuations in the availability of food resources and face the challenge of balancing energy expenditure with energy gain during periods of resource scarcity. This is likely to be particularly challenging in rugged, montane environments, where available energy is relatively low and travel costs are high. Chimpanzees (Pan troglodytes) show extensive behavioral diversity across study sites. Yet, as most research has focused on low- and mid-elevation sites, little is known on how chimpanzees respond to periods of low fruit availability in harsh montane environments. We use focal follow and phenology data to investigate how fruit availability influences daily path length and monthly home range in chimpanzees living in Nyungwe National Park, a montane forest in Rwanda. Nyungwe chimpanzees decreased their daily travel distances during periods of fruit scarcity. However, this decrease in travel effort did not correspond with a decrease in foraging area. Instead, monthly homes ranges shifted location across the study period. Nyungwe chimpanzees occupy a relatively wide altitudinal range and the shifts in monthly home range location may reflect differences in the altitudinal distribution of food resources. Chimpanzee monthly diet was often dominated by one or two species and each of these species were confined to different elevation zones. One important species, Podocarpus latifolius, grew only at high elevations (2,600-2,950 m) and chimpanzees ranged at the altitudinal peak of their range for 2 consecutive months while feeding on this species. Thus, while high elevations are often thought to be harsh environments for primates, they can be an important part of a species' home range when they provide a refugium for densely distributed, important food species.

The association between neighborhood greenness and weight status: an observational study in Perth Western Australia.

BACKGROUND: Few studies have examined the relationship between weight status and objectively measured neighborhood greenness and no study has examined this relationship across the different stages of adulthood. This research was an investigation of weight status and neighborhood greenness using objectively measured satellite remote sensing for a large population representative sample. METHOD: Cross-sectional study of 10,208 young adults (16-24 years), mid-age adults (25-64 years) and older adults (65+ years) from a population representative sample for the period 2004-2009 in Perth, Western Australia. Neighborhood greenness was ascertained for a 1600m road network service area around each participant's address using the mean and standard deviation of the Normalized Difference Vegetation Index (NDVI) obtained from remote sensing. Multiple logistic regression was used to assess associations with weight status (overweight-or-obese, obese) adjusted for socio-demographics and health-related behaviors. RESULTS: The adjusted odds ratio (OR) comparing obesity in the highest to the lowest tertile of mean greenness was 0.78 (95% CI 0.69-0.89). For the same comparison, the OR for overweight-or-obese was similar, 0.84 (95% CI 0.76-0.92). The OR comparing obesity in the highest to lowest tertile of variation in greenness was 0.75 (95% CI 0.66-0.85). For the same comparison, the OR for overweight-or-obese was similar, 0.75 (95% CI 0.68-0.82). CONCLUSION: Higher levels and greater variation of neighborhood greenness are associated with lower odds of obesity among adults of all ages. Research examining neighborhood characteristics correlated with variability in greenness will help better understand these relationships.

The impact of the built environment on health across the life course: design of a cross-sectional data linkage study.

INTRODUCTION: The built environment is increasingly recognised as being associated with health outcomes. Relationships between the built environment and health differ among age groups, especially between children and adults, but also between younger, mid-age and older adults. Yet few address differences across life stage groups within a single population study. Moreover, existing research mostly focuses on physical activity behaviours, with few studying objective clinical and mental health outcomes. The Life Course Built Environment and Health (LCBEH) project explores the impact of the built environment on self-reported and objectively measured health outcomes in a random sample of people across the life course. METHODS AND ANALYSIS: This cross-sectional data linkage study involves 15 954 children (0-15 years), young adults (16-24 years), adults (25-64 years) and older adults (65+years) from the Perth metropolitan region who completed the Health and Wellbeing Surveillance System survey administered by the Department of Health of Western Australia from 2003 to 2009. Survey data were linked to Western Australia's (WA) Hospital Morbidity Database System (hospital admission) and Mental Health Information System (mental health system outpatient) data. Participants' residential address was geocoded and features of their 'neighbourhood' were measured using Geographic Information Systems software. Associations between the built environment and self-reported and clinical health outcomes will be explored across varying geographic scales and life stages. ETHICS AND DISSEMINATION: The University of Western Australia's Human Research Ethics Committee and the Department of Health of Western Australia approved the study protocol (#2010/1). Findings will be published in peer-reviewed journals and presented at local, national and international conferences, thus contributing to the evidence base informing the design of healthy neighbourhoods for all residents.

Using GPS technology to (re)-examine operational definitions of 'neighbourhood' in place-based health research.

BACKGROUND: Inconsistencies in research findings on the impact of the built environment on walking across the life course may be methodologically driven. Commonly used methods to define 'neighbourhood', from which built environment variables are measured, may not accurately represent the spatial extent to which the behaviour in question occurs. This paper aims to provide new methods for spatially defining 'neighbourhood' based on how people use their surrounding environment. RESULTS: Informed by Global Positioning Systems (GPS) tracking data, several alternative neighbourhood delineation techniques were examined (i.e., variable width, convex hull and standard deviation buffers). Compared with traditionally used buffers (i.e., circular and polygon network), differences were found in built environment characteristics within the newly created 'neighbourhoods'. Model fit statistics indicated that exposure measures derived from alternative buffering techniques provided a better fit when examining the relationship between land-use and walking for transport or leisure. CONCLUSIONS: This research identifies how changes in the spatial extent from which built environment measures are derived may influence walking behaviour. Buffer size and orientation influences the relationship between built environment measures and walking for leisure in older adults. The use of GPS data proved suitable for re-examining operational definitions of neighbourhood.

The association between neighborhood greenness and cardiovascular disease: an observational study.

BACKGROUND: Previous studies have demonstrated links between cardiovascular disease and physical inactivity and poor air quality, which are both associated with neighborhood greenness. However, no studies have directly investigated neighborhood greenness in relation to coronary heart disease risk. We investigated the effect of neighborhood greenness on both self-reported and hospital admissions of coronary heart disease or stroke, accounting for ambient air quality, socio-demographic, behavioral and biological factors. METHOD: Cross-sectional study of 11,404 adults obtained from a population representative sample for the period 2003-2009 in Perth, Western Australia. Neighborhood greenness was ascertained for a 1600 m service area surrounding the residential address using the mean and standard deviation of the Normalized Difference Vegetation Index (NDVI) obtained from remote sensing. Logistic regression was used to assess associations with medically diagnosed and hospitalization for coronary heart disease or stroke. RESULTS: The odds of hospitalization for heart disease or stroke was 37% (95% CI: 8%, 57%) lower among adults in neighborhoods with highly variable greenness (highest tertile) compared to those in predominantly green, or predominantly non-green neighborhoods (lowest tertile). This effect was independent of the absolute levels of neighborhood greenness. There was weaker evidence for associations with the mean level of neighborhood greenness. CONCLUSION: Variability in neighborhood greenness is a single metric that encapsulates two potential promoters of physical activity - an aesthetically pleasing natural environment and access to urban destinations. Variability in greenness within a neighborhood was negatively associated with coronary heart disease and stroke.