Quantifying the activity levels and behavioural responses of butterfly species to habitat boundaries

1. The ability of species' to undergo climate‐driven range shifts across fragmented landscapes depends on their dispersal ability as well as the structure of the landscape. For species' range shifts to occur, individuals must first leave suitable habitat to seek new habitat; this is likely to depend on the rate of movement of individuals within habitat and the likelihood that a boundary is crossed, once it is encountered. For three species of butterfly with contrasting histories of recent range expansion, we examined the propensity of individuals to move within a habitat and their responses to habitat boundaries. 2. We quantified the extent to which Plebejus argus (Linnaeus) (a declining habitat specialist), Aricia agestis (Schiffermuller) (an expanding generalist) and Polymmatus icarus (Rottemburg) (a geographically ubiquitous generalist) crossed habitat boundaries into unsuitable habitat and moved within suitable habitat. The observed movement was then related to individual and environmental conditions. 3. Species differed in their activity levels in accordance within their recent distribution patterns (P. icarus > A. agestis > P. argus). Our results for P. argus suggest that movement may be motivated by nectar‐seeking, and that males generally move more than females. All three species tended to avoid crossing habitat boundaries; however the proportion of individuals crossing habitat boundaries did not differ significantly among species. 4. We conclude that levels of activity within a habitat, which will affect the frequency with which individuals encounter habitat boundaries, rather than behavioural responses to the boundaries, may be important drivers of distribution change.     

Differentiating Migration and Dispersal Processes for Pond-Breeding Amphibians

Abstract Understanding the movement of animals is critical to many aspects of conservation such as spread of emerging disease, proliferation of invasive species, changes in land-use patterns, and responses to global climate change. Movement processes are especially important for amphibian management and conservation as species declines and extinctions worldwide become ever more apparent. To better integrate behavioral and ecological data on amphibian movements with our use of spatially explicit demographic models and guide effective conservation solutions, I present 1) a synopsis of the literature regarding behavior, ecology, and evolution of movement in pond-breeding amphibians possessing biphasic life cycles to distinguish between migration and dispersal processes, 2) a working hypothesis of juvenile-based dispersal, and 3) a discussion of conservation issues that follow from distinguishing the spatial and temporal movements of amphibians at different scales. I define amphibian migration as intrapopulational, round-trip movements toward and away from aquatic breeding sites. Population-level management, in general, can be focused on spatial scales of <1.0 km with attention focused on adult population and juveniles that remain near the natal wetland. I define amphibian dispersal as interpopulational, unidirectional movements from natal sites to other breeding sites. Metapopulation- or landscape-level management can be focused on movements among populations at spatial scales >1.0–10.0 km and on importance of terrestrial connectivity. The ultimate goal of conservation for amphibians should be long-term regional persistence by addressing management issues at both local and metapopulation scales.     

The influence of spatial scale on quantifying insect dispersal: an analysis of butterfly data

Abstract. 1. A linear relationship between mean movement distances recorded and the size of the study area was found in a comparison of five mark–release–recapture studies of the meadow brown butterfly.
2. The scale impact on mean butterfly movement distances was also apparent when comparing the results for different butterfly species reported in 21 mark–release–recapture studies.     

Home range dynamics of the yellow‐footed rock‐wallaby (Petrogale xanthopus celeris) in central‐western Queensland

Analyses of the interspecific differences in macropod home range size suggest that habitat productivity exerts a greater influence on range size than does body mass. This relationship is also apparent within the rock‐wallaby genus. Lim reported that yellow‐footed rock‐wallabies (Petrogale xanthopus xanthopus) inhabiting the semi‐arid Flinders Ranges (South Australia) had a mean home range of 170 ha. While consistent with the hypothesis that species inhabiting less productive habitats will require larger ranges to fulfil their energetic requirements, the ranges reported by Lim were considerably larger than those observed for heavier sympatric macropods. The aim of the current study was to document the home range dynamics of P. x. celeris in central‐western Queensland and undertake a comparison with those reported for their southern counterparts. Wallaby movements were monitored at Idalia National Park, between winter 1992 and winter 1994. Male foraging ranges (95% fixed kernel; 15.4 ha, SD = ±7.8 ha) were found to be significantly larger than those of female wallabies (11.3 ha, SD = ±4.9 ha). Because of varying distances to the wallabies' favoured foraging ground (i.e. an adjacent herb field), the direction in which the wallabies moved to forage also significantly affected range size. Mean home range size was estimated to be 23.5 ha (SD = ±15.2 ha; 95% fixed kernel) and 67.5 ha (SD = ±22.4 ha; 100% minimum convex polygon). The discrepancy between these two estimates resulted from the exclusion of locations, from the 95% kernel estimates, when the wallabies moved to a water source 1.5 km distant from the colony site. The observed foraging and home ranges approximated those that could be expected for a macropod inhabiting the semi‐arid zone (i.e. 2.4 times larger‐than‐predicted from body mass alone). Possible reasons for the disparity between the current study and that of Lim are examined.     

Integrating batch marks and radio tags to estimate the size of a closed population with a movement model

Movement models require individually identifiable marks to estimate the movement rates among strata. But they are relatively expensive to apply and monitor. Batch marks can be readily applied, but individual animal movements cannot be identified. We describe a method to estimate population size in a stratified population when movement takes place among strata and animals are marked with a combination of batch and individually identifiable tags. A hierarchical model with Bayesian inference is developed that pools information across segments on the detection efficiency based on radio‐tagged fish and also uses the movement of the radio‐tagged fish to impute the movement of the batch‐marked fish to provide estimates of the population size on a segment and river level. The batch marks provide important information to help estimate the movement rates, but contribute little to the overall estimate of the population size. In this case, the approximate equal catchability among strata in either sample obviates the need for stratification.     

Task activity and anterior tooth grooving in prehistoric California indians.

Abraded grooves have been observed on the anterior teeth of all the adults in a small population of prehistoric California Indians. These dental effects show considerable variety, appearing on maxillary and mandibular teeth, on approximal and occulusal surfaces, and either isolated or bilaterally aligned. Although many of the grooves are indistinguishable from those reported for other prehistoric populations, their variety illustrates the limited applicability of etiological hypotheses previously proposed to account for such effects. It is suggested that the grooves represent traces of a task activity involving the pulling of fibrous materials across the teeth.     

Telemetry tag effects on juvenile lingcod Ophiodon elongatus movement: a laboratory and field study

This study tested the behavioural effects of tagging subyearling and yearling lingcod Ophiodon elongatus with acoustic telemetry tags in laboratory tanks and in the natural environment (Puget Sound, WA). In the laboratory, tagged individuals showed less movement and feeding behaviour soon after tagging than untagged controls. The effect dissipated after c. 1 week, presumably as the tagged O. elongatus recovered from surgery or adjusted to the presence of the tags. This dissipation enabled a field study that compared early‐tagged individuals with a long recovery period after tagging to recently‐tagged individuals with a short recovery period after tagging. Consistent with findings from the laboratory experiment, recently tagged individuals showed less movement away from three release sites in Puget Sound than early‐tagged individuals. Together, the laboratory and field results provide evidence of temporary tag effects on actual movement in the natural environment and provide a method for testing tag effects in the field. This study suggests that subyearling and yearling O. elongatus should be held for a recovery period before release. If holding after tagging is not an option, then movement data collected during the first week should be interpreted cautiously.     

Spatial memory and animal movement

Memory is critical to understanding animal movement but has proven challenging to study. Advances in animal tracking technology, theoretical movement models and cognitive sciences have facilitated research in each of these fields, but also created a need for synthetic examination of the linkages between memory and animal movement. Here, we draw together research from several disciplines to understand the relationship between animal memory and movement processes. First, we frame the problem in terms of the characteristics, costs and benefits of memory as outlined in psychology and neuroscience. Next, we provide an overview of the theories and conceptual frameworks that have emerged from behavioural ecology and animal cognition. Third, we turn to movement ecology and summarise recent, rapid developments in the types and quantities of available movement data, and in the statistical measures applicable to such data. Fourth, we discuss the advantages and interrelationships of diverse modelling approaches that have been used to explore the memory–movement interface. Finally, we outline key research challenges for the memory and movement communities, focusing on data needs and mathematical and computational challenges. We conclude with a roadmap for future work in this area, outlining axes along which focused research should yield rapid progress.