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Species' Use (species + use)
Selected AbstractsSearch and navigation in dynamic environments , from individual behaviors to population distributionsOIKOS, Issue 5 2008Thomas Mueller Animal movement receives widespread attention within ecology and behavior. However, much research is restricted within isolated sub-disciplines focusing on single phenomena such as navigation (e.g. homing behavior), search strategies (e.g. Levy flights) or theoretical considerations of optimal population dispersion (e.g. ideal free distribution). To help synthesize existing research, we outline a unifying conceptual framework that integrates individual-level behaviors and population-level spatial distributions with respect to spatio-temporal resource dynamics. We distinguish among (1) non-oriented movements based on diffusion and kinesis in response to proximate stimuli, (2) oriented movements utilizing perceptual cues of distant targets, and (3) memory mechanisms that assume prior knowledge of a target's location. Species' use of these mechanisms depends on life-history traits and resource dynamics, which together shape population-level patterns. Resources with little spatial variability should facilitate sedentary ranges, whereas resources with predictable seasonal variation in spatial distributions should generate migratory patterns. A third pattern, ,nomadism', should emerge when resource distributions are unpredictable in both space and time. We summarize recent advances in analyses of animal trajectories and outline three major components on which future studies should focus: (1) integration across alternative movement mechanisms involving links between state variables and specific mechanisms, (2) consideration of dynamics in resource landscapes or environments that include resource gradients in predictability, variability, scale, and abundance, and finally (3) quantitative methods to distinguish among population distributions. We suggest that combining techniques such as evolutionary programming and pattern oriented modeling will help to build strong links between underlying movement mechanisms and broad-scale population distributions. [source] Meadow Voles (Microtus pennsylvanicus) and Prairie Voles (M. ochrogaster) Differ in Their Responses to Over-Marks from Opposite- and Same-Sex ConspecificsETHOLOGY, Issue 11 2000Raymond L. Woodward Jr Over-marking occurs when one individual deposits its scent mark on the scent mark of a conspecific. Previous studies have shown that meadow voles (Microtus pennsylvanicus) and prairie voles (M. ochrogaster) that were exposed to an over-mark of two same-sex conspecifics, later responded similarly to the top-scent mark but differed in their response to the bottom-scent mark. In the present study, we examined the responses of meadow voles and prairie voles to same-sex and mixed-sex over-marks to ascertain whether their responses reflect the different tactics which males and females in promiscuous (meadow voles) and monogamous (prairie voles) species use to attract opposite-sex conspecifics and to compete with same-sex conspecifics. Males and females of both species spent more time investigating the mark of the top-scent donor than that of the bottom-scent donor of an over-mark. Meadow voles exposed to a mixed-sex over-mark spent more time investigating the mark of the opposite-sex conspecific independently of whether it was from the top- or bottom-scent donor. In contrast, prairie voles spent more time investigating the mark of the opposite-sex donor if it was from the top-scent donor. These results suggest that: (i) over-marking serves a competitive function; (ii) the scent marks of individuals attract multiple mates in promiscuous species such as the meadow vole; and (iii) the scent marks of individuals establish and maintain pair bonds between familiar opposite-sex conspecifics in monogamous species such as the prairie vole. [source] Breeding habitat use and the future management of the critically endangered Southern Corroboree FrogECOLOGICAL MANAGEMENT & RESTORATION, Issue 2009David Hunter Summary The Southern Corroboree Frog (Pseudophryne corroboree) is one of Australia's most critically endangered frog species. The species occurs entirely within Kosciuszko National Park, which has a history of cattle grazing (up to the 1970s). A consequence of cattle grazing has been a significant reduction in the extent of montane and sub-alpine peat-bog systems that the species uses as breeding habitat. Furthermore, climate change and associated increased wildfire frequency is expected to further reduce the extent and quality of peat bogs throughout the Australian Alps. In this study, we investigated habitat selection for breeding pools and nest sites within peat-bog systems in order to inform the conservation management of the species and guide other management practices being undertaken in peat bogs where this species occurs. Occupancy of breeding males at bog pools was found to be positively associated with increasing pool area, water depth and mid-day temperature, and negatively associated with extent of bare substrate. The majority of breeding pools identified were ephemeral. Nest sites within vegetation where males call and where females deposit their eggs were located at mid-elevations in a range of vegetation types, with the majority of nests being within moss and sedge dominated by Sphagnum cristatum and Empodisma minor. We also found that male nest sites were not randomly distributed within the edges of pools, but were more often located in areas of loose vegetation. These results highlight the potential sensitivity of the Southern Corroboree Frog to predicted changes in peat-bog systems resulting from climate change such as earlier drying and a possible reduction in the size of bog pools. A monitoring programme focused on key features of the breeding habitat should be undertaken to provide a basis for developing and assessing management actions implemented in peat bogs occupied by this species. [source] Multi-scale occupancy estimation and modelling using multiple detection methodsJOURNAL OF APPLIED ECOLOGY, Issue 5 2008James D. Nichols Summary 1Occupancy estimation and modelling based on detection,nondetection data provide an effective way of exploring change in a species' distribution across time and space in cases where the species is not always detected with certainty. Today, many monitoring programmes target multiple species, or life stages within a species, requiring the use of multiple detection methods. When multiple methods or devices are used at the same sample sites, animals can be detected by more than one method. 2We develop occupancy models for multiple detection methods that permit simultaneous use of data from all methods for inference about method-specific detection probabilities. Moreover, the approach permits estimation of occupancy at two spatial scales: the larger scale corresponds to species' use of a sample unit, whereas the smaller scale corresponds to presence of the species at the local sample station or site. 3We apply the models to data collected on two different vertebrate species: striped skunks Mephitis mephitis and red salamanders Pseudotriton ruber. For striped skunks, large-scale occupancy estimates were consistent between two sampling seasons. Small-scale occupancy probabilities were slightly lower in the late winter/spring when skunks tend to conserve energy, and movements are limited to males in search of females for breeding. There was strong evidence of method-specific detection probabilities for skunks. As anticipated, large- and small-scale occupancy areas completely overlapped for red salamanders. The analyses provided weak evidence of method-specific detection probabilities for this species. 4Synthesis and applications. Increasingly, many studies are utilizing multiple detection methods at sampling locations. The modelling approach presented here makes efficient use of detections from multiple methods to estimate occupancy probabilities at two spatial scales and to compare detection probabilities associated with different detection methods. The models can be viewed as another variation of Pollock's robust design and may be applicable to a wide variety of scenarios where species occur in an area but are not always near the sampled locations. The estimation approach is likely to be especially useful in multispecies conservation programmes by providing efficient estimates using multiple detection devices and by providing device-specific detection probability estimates for use in survey design. [source] | ||||||||||