Foraging theory upscaled: the behavioural ecology of herbivore movement

A random acceleration model of individual animal movement allowing for diffusive, superdiffusive and superballistic regimes

Patterns of individual animal movement attracted considerable attention over the last two decades. In particular, question as to whether animal movement is predominantly diffusive or superdiffusive has been a focus of discussion and controversy. We consider this problem using a theory of stochastic motion based on the Langevin equation with non-Wiener stochastic forcing that originates in animal’s response to environmental noise. We show that diffusive and superdiffusive types of motion are inherent parts of the same general movement process that arises as interplay between the force exerted by animals (essentially, by animal’s muscles) and the environmental drag. The movement is superballistic with the mean square displacement growing with time as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle {x}^{2}(t)\rangle \sim {t}^{4}$$\end{document}〈x2(t)〉∼t4 at the beginning and eventually slowing down to the diffusive spread \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle {x}^{2}(t)\rangle \sim t$$\end{document}〈x2(t)〉∼t. We show that the duration of the superballistic and superdiffusive stages can be long depending on the properties of the environmental noise and the intensity of drag. Our findings demonstrate theoretically how the movement pattern that includes diffusive and superdiffusive/superballistic motion arises naturally as a result of the interplay between the dissipative properties of the environment and the animal’s biological traits such as the body mass, typical movement velocity and the typical duration of uninterrupted movement.

Experience matters: context-dependent decisions explain spatial foraging patterns in the deposit-feeding crab Scopimera intermedia

Behavioural decisions are often context-dependent, where information from immediate experience is incorporated into an individual's decision-making, particularly in complex environments. To test whether such mechanism is adopted by foragers in heterogeneous environments, we investigated the foraging behaviour of the deposit-feeding sand-bubbler crab, Scopimera intermedia An individual-based model was constructed, based on an optimal-patch selection criterion, which implicitly assumed that individuals adjust foraging decisions based on immediate past experience. The model's predictions were tested on the shore by manipulating the location of food patches, where the crab showed a strong context-dependent foraging pattern. When resources were randomly distributed, the crab responded by spending 56% of time in enriched patches compared with only 28% in the same area when patches were composed of natural sediments. Shore manipulations varying resource distribution supported the underlying principles of the model mechanism, and highlighted the benefits of such a strategy in heterogeneous environments such as intertidal sediments where food resources vary at different spatial and temporal scales. The proposed model therefore provides a mechanistic process, based on optimal foraging, to predict foraging decisions and movement patterns of animals feeding in heterogeneous landscapes.

Estimation of baboon daily travel distances by means of point sampling - the magnitude of underestimation

Daily travel distance (DTD), the distance an animal moves over the course of the day, is an important metric in movement ecology. It provides data with which to test hypotheses related to energetics and behaviour, e.g. impact of group size or food distribution on DTDs. The automated tracking of movements by applying GPS technology has become widely available and easy to implement. However, due to battery duration constraints, it is necessary to select a tracking-time resolution, which inevitably introduces an underestimation of the true underlying path distance. Here we give a quantification of this inherent systematic underestimation of DTDs for a terrestrial primate, the Guinea baboon. We show that sampling protocols with interval lengths from 1 to 120 min underestimate DTDs on average by 7 to 35 %. For longer time intervals (i.e. 60, 90, 120 min), the relative increase of deviation from the “true” trajectory is less pronounced than for shorter intervals. Our study provides first hints on the magnitude of error, which can be applied as a corrective when estimating absolute DTDs in calculations on travelling costs in terrestrial primates.

Changes of foraging patch selection and utilization by a giant panda after bamboo flowering

The bamboo flowering leads to the habitat fragmentation and food quality decline of a giant panda. Few empirical research has been conducted about the giant panda's response to the bamboo flowering. Here, we investigated the characteristics of bamboo stands, giant panda's activity, and selection and utilization of bamboo stands by giant panda in Taibaishan National Nature Reserve, China, over a 3-year period (September 2013-May 2016) during the Fargesia qinlingensis flowering period. Our results indicated that the proportion of whole bamboo stands flowering has gradually expanded from 26.7% in 2013 and 33.9% in 2014 to 52.3% in 2015. Although the flowering bamboo has lower crude protein and higher crude fiber than a non-flowering bamboo, the giant panda still fed on flowering bamboo from the evidence of droppings. The giant panda left its feeding sites and moved to the high elevation along river when the proportion of flowering reached 69.2% at elevation of 2350-2450 m in the third year. With the decline of the quality of bamboo stand of Fargesia qinlingensis, the giant panda abandoned its feeding sites when the threshold value of bamboo flowering reached 56.9-69.2%. Flexibility in foraging strategy and spatial behavior can help the giant panda to better adapt to the environment.

Effects of environmental factors and landscape features on movement patterns of Florida black bears

A greater understanding of how environmental factors and anthropogenic landscape features influence animal movements can inform management and potentially aid in mitigating human–wildlife conflicts. We investigated the movement patterns of 16 Florida black bears (Ursus americanus floridanus; 6 females, 10 males) in north-central Florida at multiple temporal scales using GPS data collected from 2011 to 2014. We calculated bi-hourly step-lengths and directional persistence, as well as daily and weekly observed displacements and expected displacements. We used those movement metrics as response variables in linear mixed models and tested for effects of sex, season, and landscape features. We found that step-lengths of males were generally longer than step-lengths of females, and both sexes had the shortest step-lengths during the daytime. Bears moved more slowly (shorter step-lengths) and exhibited less directed movement when near creeks, in forested wetlands, and in marsh habitats, possibly indicating foraging behavior. In urban areas, bears moved more quickly (longer step-lengths) and along more directed paths. The results were similar across all temporal scales. Major roads tended to act as a semipermeable barrier to bear movement. Males crossed major roads more frequently than females but both sexes crossed major roads much less frequently than minor roads. Our findings regarding the influence of landscape and habitat features on movement patterns of Florida black bears could be useful for planning effective wildlife corridors and understanding how future residential or commercial development and road expansions may affect animal movement.

Ungulates rely less on visual cues, but more on adapting movement behaviour, when searching for forage

Finding suitable forage patches in a heterogeneous landscape, where patches change dynamically both spatially and temporally could be challenging to large herbivores, especially if they have no a priori knowledge of the location of the patches. We tested whether three large grazing herbivores with a variety of different traits improve their efficiency when foraging at a heterogeneous habitat patch scale by using visual cues to gain a priori knowledge about potential higher value foraging patches. For each species (zebra (Equus burchelli), red hartebeest (Alcelaphus buselaphus subspecies camaa) and eland (Tragelaphus oryx)), we used step lengths and directionality of movement to infer whether they were using visual cues to find suitable forage patches at a habitat patch scale. Step lengths were significantly longer for all species when moving to non-visible patches than to visible patches, but all movements showed little directionality. Of the three species, zebra movements were the most directional. Red hartebeest had the shortest step lengths and zebra the longest. We conclude that these large grazing herbivores may not exclusively use visual cues when foraging at a habitat patch scale, but would rather adapt their movement behaviour, mainly step length, to the heterogeneity of the specific landscape.

Withered on the stem: is bamboo a seasonally limiting resource for giant pandas?

In response to seasonal variation in quality and quantity of available plant biomass, herbivorous foragers may alternate among different plant resources to meet nutritional requirements. Giant pandas (Ailuropoda melanoleuca) are reliant almost exclusively on bamboo which appears omnipresent in most occupied habitat, but subtle temporal variation in bamboo quality may still govern foraging strategies, with population-level effects. In this paper, we investigated the possibility that temporal variation in the quality of this resource is involved in population regulation and examined pandas' adaptive foraging strategies in response to temporal variation in bamboo quality. Giant pandas in late winter and early spring consumed a less optimal diet in Foping Nature Reserve, as the availability of the most nutritious and preferred components and age classes of Bashania fargesii declined, suggesting that bamboo may be a seasonally limiting resource. Most panda mortalities and rescues occurred during the same period of seasonal food limitation. Our findings raised the possibility that while total bamboo biomass may not be a limiting factor, carrying capacity may be influenced by subtle seasonal variation in bamboo quality. We recommend that managers and policy-makers should consider more than just the quantity of bamboo in the understory and that carrying capacity estimates should be revised downward to reflect the fact that all bamboos are not equal.

Complex variation in habitat selection strategies among individuals driven by extrinsic factors

Understanding behavioral strategies employed by animals to maximize fitness in the face of environmental heterogeneity, variability, and uncertainty is a central aim of animal ecology. Flexibility in behavior may be key to how animals respond to climate and environmental change. Using a mechanistic modeling framework for simultaneously quantifying the effects of habitat preference and intrinsic movement on space use at the landscape scale, we investigate how movement and habitat selection vary among individuals and years in response to forage quality–quantity tradeoffs, environmental conditions, and variable annual climate. We evaluated the association of dynamic, biotic forage resources and static, abiotic landscape features with large grazer movement decisions in an experimental landscape, where forage resources vary in response to prescribed burning, grazing by a native herbivore, the plains bison (Bison bison bison), and a continental climate. Our goal was to determine how biotic and abiotic factors mediate bison movement decisions in a nutritionally heterogeneous grassland. We integrated spatially explicit relocations of GPS‐collared bison and extensive vegetation surveys to relate movement paths to grassland attributes over a time period spanning a regionwide drought and average weather conditions. Movement decisions were affected by foliar crude content and low stature forage biomass across years with substantial interannual variation in the magnitude of selection for forage quality and quantity. These differences were associated with interannual differences in climate and growing conditions from the previous year. Our results provide experimental evidence for understanding how the forage quality–quantity tradeoff and fine‐scale topography drives fine‐scale movement decisions under varying environmental conditions.

Straight from the caribou’s (Rangifer tarandus) mouth: detailed observations of tame caribou reveal new insights into summer–autumn diets

High-quality habitats for caribou (Rangifer tarandus (L., 1758)) are associated primarily with lichens, but lichens alone fail to satisfy summer nutritional requirements. To evaluate the summer forage value of plant communities across northeastern British Columbia (BC), where populations of northern and boreal ecotypes of caribou are declining, we observed foraging by tame, female caribou. We compared diet composition with forage abundance to determine forage selection and to quantify forage availability. Deciduous shrubs, not lichens, largely dominated summer diets. Caribou were highly selective foragers, with 28 species comprising 78% of diets. Caribou avoided ≥50% of understory vegetation in all communities, especially conifers, evergreen shrubs, mosses, and two genera of terrestrial lichens. Availability of accepted forage (species not avoided) was strongly heterogeneous across landscapes. Alpine shrub areas and mid-elevation spruce–fir stands in the mountains, as well as treed rich fens and white spruce communities in the boreal forests, provided the greatest quantities of accepted forage for caribou. Dry alpine sites and unproductive black spruce communities provided the least accepted forage. Our work has direct implications to caribou conservation by contributing to a greater understanding of the forage value of summer habitats, with implications to habitat selection, seasonal movements, and distribution ecology.

Grazing management: setting the table, designing the menu and influencing the diner

Pastoral livestock-production systems are under increasing environmental, social and consumer pressures to reduce environmental impacts and to enhance biodiversity and animal welfare. At the same time, farmers face the challenge of managing grazing, which is intimately linked with profitability. Recent advances in understanding grazing patterns and nutritional ecology may help alleviate such pressures. For instance, by managing grazing to (1) manipulate links between ingestive–digestive decisions and temporal patterns of nutrient excretion, (2) provide phytochemically diverse diets at appropriate temporal (the menu) and spatial (the table) scales and (3) influence the behaviour of animals (the diners) on the basis of their specific ‘personalities’ and needs, to overcome or enhance animal differences, thereby enhancing their and farm productivity and welfare, as well as our health. Under pastoral systems, synergies between animals’ and farmers’ grazing decisions have the potential to offer greater benefits to the animal, the environment and the farm than does simple and parsimonious grazing management based on a single component of the system. In the present review, we look at grazing and its management through an alternate lens, drawing ideas and hypotheses to stimulate thinking, dialogue and discussions that we anticipate will evolve into innovative research programs and grazing strategies. To do so, we combined experimental and observational studies from a wide range of disciplines with simulation-modelling exercises. We envisage a more holistic approach to manage grazing based on recent advances in the understanding of the nutritional ecology of grazing animals, and propose management practices that may enable pastoral livestock-production systems to evolve continually as complex creative systems.

Pastoralists as Optimal Foragers? Reoccupation and Site Selection in the Deserts of Post-Soviet Kazakhstan

This study explores the drivers of site selection amongst livestock owners under conditions of increasing animal numbers following a low point in the 1990s. Our major goal was to understand whether livestock owners are acting as 'optimal foragers,' targeting areas of highest forage availability as they colonise previously empty areas. The results presented here suggest that they do not. Initially, distance from home settlement was the dominant determinant of site occupancy, with closer sites occupied earlier regardless of other characteristics. Some owners remained on depleted vegetation for longer than would be predicted under conditions of optimal foraging, indicating that distance-related costs constrained resource matching. In the latter period, increases in livestock wealth encouraged the occupation of distant sites exhibiting higher vegetation density and water quality, but some owners still occupied highly depleted sites. Improved transport and water supply infrastructure are needed if pastoralists are to optimise resource use across the landscape.

Movement reveals scale dependence in habitat selection of a large ungulate

Ecological processes operate across temporal and spatial scales. Anthropogenic disturbances impact these processes, but examinations of scale dependence in impacts are infrequent. Such examinations can provide important insight to wildlife-human interactions and guide management efforts to reduce impacts. We assessed spatiotemporal scale dependence in habitat selection of mule deer (Odocoileus hemionus) in the Piceance Basin of Colorado, USA, an area of ongoing natural gas development. We employed a newly developed animal movement method to assess habitat selection across scales defined using animal-centric spatiotemporal definitions ranging from the local (defined from five hour movements) to the broad (defined from weekly movements). We extended our analysis to examine variation in scale dependence between night and day and assess functional responses in habitat selection patterns relative to the density of anthropogenic features. Mule deer displayed scale invariance in the direction of their response to energy development features, avoiding well pads and the areas closest to roads at all scales, though with increasing strength of avoidance at coarser scales. Deer displayed scale-dependent responses to most other habitat features, including land cover type and habitat edges. Selection differed between night and day at the finest scales, but homogenized as scale increased. Deer displayed functional responses to development, with deer inhabiting the least developed ranges more strongly avoiding development relative to those with more development in their ranges. Energy development was a primary driver of habitat selection patterns in mule deer, structuring their behaviors across all scales examined. Stronger avoidance at coarser scales suggests that deer behaviorally mediated their interaction with development, but only to a degree. At higher development densities than seen in this area, such mediation may not be possible and thus maintenance of sufficient habitat with lower development densities will be a critical best management practice as development expands globally.

A random walk description of individual animal movement accounting for periods of rest

Animals do not move all the time but alternate the period of actual movement (foraging) with periods of rest (e.g. eating or sleeping). Although the existence of rest times is widely acknowledged in the literature and has even become a focus of increased attention recently, the theoretical approaches to describe animal movement by calculating the dispersal kernel and/or the mean squared displacement (MSD) rarely take rests into account. In this study, we aim to bridge this gap. We consider a composite stochastic process where the periods of active dispersal or 'bouts' (described by a certain baseline probability density function (pdf) of animal dispersal) alternate with periods of immobility. For this process, we derive a general equation that determines the pdf of this composite movement. The equation is analysed in detail in two special but important cases such as the standard Brownian motion described by a Gaussian kernel and the Levy flight described by a Cauchy distribution. For the Brownian motion, we show that in the large-time asymptotics the effect of rests results in a rescaling of the diffusion coefficient. The movement occurs as a subdiffusive transition between the two diffusive asymptotics. Interestingly, the Levy flight case shows similar properties, which indicates a certain universality of our findings.

Spatial synchrony in population dynamics: The effects of demographic stochasticity and density regulation with a spatial scale

We generalize a previous simple result by Lande et al. (1999) on how spatial autocorrelated noise, dispersal rate and distance as well as strength of density regulation determine the spatial scale of synchrony in population density. It is shown how demographic noise can be incorporated, what effect it has on variance and spatial scale of synchrony, and how it interacts with the point process for locations of individuals under random sampling. Although the effect of demographic noise is a rather complex interaction with environmental noise, migration and density regulation, its effect on population fluctuations and scale of synchrony can be presented in a transparent way. This is achieved by defining a characteristic area dependent on demographic and environmental variances as well as population density, and subsequently using this area to define a spatial demographic coefficient. The demographic noise acts through this coefficient on the spatial synchrony, which may increase or decrease with increasing demographic noise depending on other parameters. A second generalization yields the modeling of density regulation taking into account that regulation at a given location does not only depend on the density at that site but also on densities in the whole territory or home range of individuals. It is shown that such density regulation with a spatial scale reduces the scale of synchrony in population fluctuations relative to the simpler model with density regulation at each location determined only by the local point density, and may even generate negative spatial autocorrelations.

Path segmentation for beginners: an overview of current methods for detecting changes in animal movement patterns

Increased availability of high-resolution movement data has led to the development of numerous methods for studying changes in animal movement behavior. Path segmentation methods provide basics for detecting movement changes and the behavioral mechanisms driving them. However, available path segmentation methods differ vastly with respect to underlying statistical assumptions and output produced. Consequently, it is currently difficult for researchers new to path segmentation to gain an overview of the different methods, and choose one that is appropriate for their data and research questions. Here, we provide an overview of different methods for segmenting movement paths according to potential changes in underlying behavior. To structure our overview, we outline three broad types of research questions that are commonly addressed through path segmentation: 1) the quantitative description of movement patterns, 2) the detection of significant change-points, and 3) the identification of underlying processes or 'hidden states'. We discuss advantages and limitations of different approaches for addressing these research questions using path-level movement data, and present general guidelines for choosing methods based on data characteristics and questions. Our overview illustrates the large diversity of available path segmentation approaches, highlights the need for studies that compare the utility of different methods, and identifies opportunities for future developments in path-level data analysis.

Behaviour-Related Scalar Habitat Use by Cape Buffalo (Syncerus caffer caffer)

Studies of habitat use by animals must consider behavioural resource requirements at different scales, which could influence the functional value of different sites. Using Cape buffalo (Syncerus caffer caffer) in the Okavango Delta, Botswana, we tested the hypotheses that behaviour affected use between and within habitats, hereafter referred to as macro- and microhabitats, respectively. We fitted GPS-enabled collars to fifteen buffalo and used the distances and turning angles between consecutive fixes to cluster the resulting data into resting, grazing, walking and relocating behaviours. Distance to water and six vegetation characteristic variables were recorded in sites used for each behaviour, except for relocating, which occurred too infrequently. We used multilevel binomial and multinomial logistic regressions to identify variables that characterised seasonally-preferred macrohabitats and microhabitats used for different behaviours. Our results showed that macrohabitat use was linked to behaviour, although this was least apparent during the rainy season, when resources were most abundant. Behaviour-related microhabitat use was less significant, but variation in forage characteristics could predict some behaviour within all macrohabitats. The variables predicting behaviour were not consistent, but resting and grazing sites were more readily identifiable than walking sites. These results highlight the significance of resting, as well as foraging, site availability in buffalo spatial processes. Our results emphasise the importance of considering several behaviours and scales in studies of habitat use to understand the links between environmental resources and animal behavioural and spatial ecology.

How animals move along? Exactly solvable model of superdiffusive spread resulting from animal's decision making

Patterns of individual animal movement have been a focus of considerable attention recently. Of particular interest is a question how different macroscopic properties of animal dispersal result from the stochastic processes occurring on the microscale of the individual behavior. In this paper, we perform a comprehensive analytical study of a model where the animal changes the movement velocity as a result of its behavioral response to environmental stochasticity. The stochasticity is assumed to manifest itself through certain signals, and the animal modifies its velocity as a response to the signals. We consider two different cases, i.e. where the change in the velocity is or is not correlated to its current value. We show that in both cases the early, transient stage of the animal movement is super-diffusive, i.e. ballistic. The large-time asymptotic behavior appears to be diffusive in the uncorrelated case but super-ballistic in the correlated case. We also calculate analytically the dispersal kernel of the movement and show that, whilst it converge to a normal distribution in the large-time limit, it possesses a fatter tail during the transient stage, i.e. at early and intermediate time. Since the transients are known to be highly relevant in ecology, our findings may indicate that the fat tails and superdiffusive spread that are sometimes observed in the movement data may be a feature of the transitional dynamics rather than an inherent property of the animal movement.

Space-Use Patterns of the Asiatic Wild Ass (Equus hemionus): Complementary Insights from Displacement, Recursion Movement and Habitat Selection Analyses

The way in which animals move and use the landscape is influenced by the spatial distribution of resources, and is of importance when considering species conservation. We aimed at exploring how landscape-related factors affect a large herbivore's space-use patterns by using a combined approach, integrating movement (displacement and recursions) and habitat selection analyses. We studied the endangered Asiatic wild ass (Equus hemionus) in the Negev Desert, Israel, using GPS monitoring and direct observation. We found that the main landscape-related factors affecting the species' space-use patterns, on a daily and seasonal basis, were vegetation cover, water sources and topography. Two main habitat types were selected: high-elevation sites during the day (specific microclimate: windy on warm summer days) and streambed surroundings during the night (coupled with high vegetation when the animals were active in summer). Distribution of recursion times (duration between visits) revealed a 24-hour periodicity, a pattern that could be widespread among large herbivores. Characterizing frequently revisited sites suggested that recursion movements were mainly driven by a few landscape features (water sources, vegetation patches, high-elevation points), but also by social factors, such as territoriality, which should be further explored. This study provided complementary insights into the space-use patterns of E. hemionus. Understanding of the species' space-use patterns, at both large and fine spatial scale, is required for developing appropriate conservation protocols. Our approach could be further applied for studying the space-use patterns of other species in heterogeneous landscapes.

Isotopic Differences between Forage Consumed by a Large Herbivore in Open, Closed, and Coastal Habitats: New Evidence from a Boreal Study System

Documenting habitat-related patterns in foraging behaviour at the individual level and over large temporal scales remains challenging for large herbivores. Stable isotope analysis could represent a valuable tool to quantify habitat-related foraging behaviour at the scale of individuals and over large temporal scales in forest dwelling large herbivores living in coastal environments, because the carbon (δ13C) or nitrogen (δ15N) isotopic signatures of forage can differ between open and closed habitats or between terrestrial and littoral forage, respectively. Here, we examined if we could detect isotopic differences between the different assemblages of forage taxa consumed by white-tailed deer that can be found in open, closed, supralittoral, and littoral habitats. We showed that δ13C of assemblages of forage taxa were 3.0 ‰ lower in closed than in open habitats, while δ15N were 2.0 ‰ and 7.4 ‰ higher in supralittoral and littoral habitats, respectively, than in terrestrial habitats. Stable isotope analysis may represent an additional technique for ecologists interested in quantifiying the consumption of terrestrial vs. marine autotrophs. Yet, given the relative isotopic proximity and the overlap between forage from open, closed, and supralittoral habitats, the next step would be to determine the potential to estimate their contribution to herbivore diet.

Seagrass Herbivory Levels Sustain Site-Fidelity in a Remnant Dugong Population

Herds of dugong, a largely tropical marine megaherbivore, are known to undertake long-distance movements, sequentially overgrazing seagrass meadows in their path. Given their drastic declines in many regions, it is unclear whether at lower densities, their grazing is less intense, reducing their need to travel between meadows. We studied the effect of the feeding behaviour of a small dugong population in the Andaman and Nicobar archipelago, India to understand how small isolated populations graze seagrasses. In the seven years of our observation, all recorded dugongs travelled either solitarily or in pairs, and their use of seagrasses was limited to 8 meadows, some of which were persistently grazed. These meadows were relatively large, contiguous and dominated by short-lived seagrasses species. Dugongs consumed approximately 15% of meadow primary production, but there was a large variation (3-40% of total meadow production) in consumption patterns between meadows. The impact of herbivory was relatively high, with shoot densities c. 50% higher inside herbivore exclosures than in areas exposed to repeated grazing. Our results indicate that dugongs in the study area repeatedly graze the same meadows probably because the proportion of primary production consumed reduces shoot density to levels that are still above values that can trigger meadow abandonment. This ability of seagrasses to cope perhaps explains the long-term site fidelity shown by individual dugongs in these meadows. The fact that seagrass meadows in the archipelago are able to support dugong foraging requirements allows us to clearly identify locations where this remnant population persists, and where urgent management efforts can be directed.

Comparison of microhabitats and foraging strategies between the captive-born Zhangxiang and wild giant pandas: implications for future reintroduction

The female giant panda Zhangxiang (pedigree number 826) was born on August 20, 2011 in Wolong Nature Reserve, China. On November 6, 2013, Zhangxiang was transported into the acclimatization enclosure in the Liziping Nature Reserve. Before Zhangxiang left the enclosure into the wild, we conducted the first study to compare microhabitats and foraging strategies between Zhangxiang in the enclosure and giant pandas in the wild. Compared with the latter, microhabitats of Zhangxiang in the enclosure are characteristic of gentler slope, more trees, higher canopy, smaller tree DBH, and lower density of living bamboos. Diet composition and foraging behaviors significantly differed between Zhangxiang and wild giant pandas, perhaps reflecting the combined consequence of environmental conditions (e.g., bamboo species) and individual status (e.g., age, mastication ability, etc.). The difference in microhabitats and foraging strategies between Zhangxiang and wild giant pandas implied that after being released into the natural habitat in the reserve, Zhangxiang will have to adapt to the environmental conditions once again. For future reintroduction, the enclosure can be extended to the Bashania spanostachya forest in the reserve, and captive giant pandas for release can thus normally transit into the wild without human intervention during acclimatization period. For other acclimatization enclosures to be constructed in the future, ecological environment inside, including topography, forests, and bamboos as well, should as possible as can match the habitat that the giant panda to-be-reinforced populations inhabit.

Spatial scale and movement behaviour traits control the impacts of habitat fragmentation on individual fitness

Habitat fragmentation, that is the breaking apart of habitat, can occur at multiple spatial scales at the same time, as a result of different land uses. Individuals of most species spend different amounts of times moving in different modes, during which they cover different distances and experience different fitness impacts. The scale at which fragmentation occurs interacts with the distance that individuals move in a particular mode to affect an individual's ability to find habitat. However, there is little knowledge of the fitness consequences of different scales of fragmentation for individuals with different traits of movement behaviour. This is critical to understand the mechanisms of persistence of different species in fragmented landscapes. The aim of this study was to quantify the impacts of habitat fragmentation at different scales on the fitness components (reproduction and survival) of individuals with different traits of movement behaviour. We developed a demographic model of individuals that adopt short and tortuous movements within foraging areas (foraging mode) and long and straight movements between foraging areas (searching mode). We considered individuals that adopt different movement modes with varying frequencies, inherently move different searching distances and experience different risks of mortality during searching. We then applied the model within a spatially explicit simulation framework where we varied simultaneously the degree of fragmentation within (fine scale) and between foraging areas (coarse scale). Fine-scale fragmentation had a greater impact on reproduction and survival than coarse-scale fragmentation, for those individuals with a low searching propensity. The impact of fine-scale fragmentation on reproduction and survival interacted with the impact of coarse-scale fragmentation on reproduction and survival, to affect the fitness of individuals with a high searching propensity, large inherent searching distances and high searching mortality rates. Habitat selection strongly mitigated the impact of the scale at which fragmentation occurred on individual fitness. Our findings suggest that the land use to target with conservation actions to reduce fragmentation, such as financial schemes that promote re-vegetation or retention of standing vegetation, depends on the scale at which fragmentation occurs and the movement behaviour traits of the species of conservation concern.

Short communication: grazing pattern of dairy cows that were selected for divergent residual feed intake as calves

The aim of this study was to investigate and assess differences in the grazing pattern of 2 groups of mature dairy cows selected as calves for divergent residual feed intake (RFI). Sixteen Holstein-Friesian cows (471±31kg of body weight, 100 d in milk), comprising 8 cows selected as calves (6-8 mo old) for low (most efficient: CSCLowRFI) and 8 cows selected as calves for high (least efficient: CSCHighRFI) RFI, were used for the purpose of this study. Cows (n=16) were managed as a single group, and strip-grazed (24-h pasture allocation at 0800h) a perennial ryegrass sward for 31 d, with measurements taken during the last 21 d. All cows were equipped with motion sensors for the duration of the study, and jaw movements were measured for three 24-h periods during 3 random nonconsecutive days. Measurements included number of steps and jaw movements during grazing and rumination, plus fecal particle size distribution. Jaw movements were analyzed to identify bites, mastication (oral processing of ingesta) during grazing bouts, chewing during rumination, and to calculate grazing and rumination times for 24-h periods. Grazing and walking behavior were also analyzed in relation to the first meal of the day after the new pasture was allocated. Measured variables were subjected to multivariate analysis. Cows selected for low RFI as calves appeared to (a) prioritize grazing and rumination over idling; (b) take fewer steps, but with a higher proportion of grazing steps at the expense of nongrazing steps; and (c) increase the duration of the first meal and commenced their second meal earlier than CSCHighRFI. The CSCLowRFI had fewer jaw movements during eating (39,820 vs. 45,118 for CSCLowRFI and CSCHighRFI, respectively), more intense rumination (i.e., 5 more chews per bolus), and their feces had 30% less large particles than CSCHighRFI. These results suggest that CSCLowRFI concentrate their grazing activity to the time when fresh pasture is allocated, and graze more efficiently by walking and masticating less, hence they are more efficient grazers than CSCHighRFI.

Deriving Animal Behaviour from High-Frequency GPS: Tracking Cows in Open and Forested Habitat

The increasing spatiotemporal accuracy of Global Navigation Satellite Systems (GNSS) tracking systems opens the possibility to infer animal behaviour from tracking data. We studied the relationship between high-frequency GNSS data and behaviour, aimed at developing an easily interpretable classification method to infer behaviour from location data. Behavioural observations were carried out during tracking of cows (Bos Taurus) fitted with high-frequency GPS (Global Positioning System) receivers. Data were obtained in an open field and forested area, and movement metrics were calculated for 1 min, 12 s and 2 s intervals. We observed four behaviour types (Foraging, Lying, Standing and Walking). We subsequently used Classification and Regression Trees to classify the simultaneously obtained GPS data as these behaviour types, based on distances and turning angles between fixes. GPS data with a 1 min interval from the open field was classified correctly for more than 70% of the samples. Data from the 12 s and 2 s interval could not be classified successfully, emphasizing that the interval should be long enough for the behaviour to be defined by its characteristic movement metrics. Data obtained in the forested area were classified with a lower accuracy (57%) than the data from the open field, due to a larger positional error of GPS locations and differences in behavioural performance influenced by the habitat type. This demonstrates the importance of understanding the relationship between behaviour and movement metrics, derived from GNSS fixes at different frequencies and in different habitats, in order to successfully infer behaviour. When spatially accurate location data can be obtained, behaviour can be inferred from high-frequency GNSS fixes by calculating simple movement metrics and using easily interpretable decision trees. This allows for the combined study of animal behaviour and habitat use based on location data, and might make it possible to detect deviations in behaviour at the individual level.

Identifying Space Use at Foraging Arena Scale within the Home Ranges of Large Herbivores

An intermediate spatiotemporal scale of food procurement by large herbivores is evident within annual or seasonal home ranges. It takes the form of settlement periods spanning several days or weeks during which foraging activity is confined to spatially discrete foraging arenas, separated by roaming interludes. Extended by areas occupied for other activities, these foraging arenas contribute towards generating the home range structure. We delineated and compared the foraging arenas exploited by two African large herbivores, sable antelope (a ruminant) and plains zebra (a non-ruminant), using GPS-derived movement data. We developed a novel approach to specifically delineate foraging arenas based on local change points in distance relative to adjoining clusters of locations, and compared its output with modifications of two published methods developed for home range estimation and residence time estimation respectively. We compared how these herbivore species responded to seasonal variation in food resources and how they differed in their spatial patterns of resource utilization. Sable antelope herds tended to concentrate their space use locally, while zebra herds moved more opportunistically over a wider set of foraging arenas. The amalgamated extent of the foraging arenas exploited by sable herds amounted to 12-30 km2, compared with 22-100 km2 for the zebra herds. Half-day displacement distances differed between settlement periods and roaming interludes, and zebra herds generally shifted further over 12h than sable herds. Foraging arenas of sable herds tended to be smaller than those of zebra, and were occupied for period twice as long, and hence exploited more intensively in days spent per unit area than the foraging arenas of zebra. For sable both the intensity of utilization of foraging arenas and proportion of days spent in foraging arenas relative to roaming interludes declined as food resources diminished seasonally, while zebra showed no seasonal variation in these metrics. Identifying patterns of space use at foraging arena scale helps reveal mechanisms generating the home range extent, and in turn the local population density. Thereby it helps forge links between behavioural ecology, movement ecology and population ecology.