Spatial Patterns Of Habitat Use Research Articles

The method matters. A comparative study of biologging and camera traps as data sources with which to describe wildlife habitat selection

Habitat use is a virtually universal activity among animals and is highly relevant as regards designing wildlife management and conservation actions. This has led to the development of a great variety of methods to study it, of which resource selection functions combined with biologging-derived data (RSF) is the most widely used for this purpose. However this approach has some constraints, such as its invasiveness and high costs. Analytical approaches taking into consideration imperfect detection coupled with camera trap data (IDM) have, therefore, emerged as a non-invasive cost-effective alternative. However, despite the fact that both approaches (RSF and IDM) have been used in habitat selection studies, they should also be comparatively assessed. The objective of this work is consequently to assess them from two perspectives: explanatory and predictive. This has been done by analyzing data obtained from camera traps (60 sampling sites) and biologging (17 animals monitored: 7 red deer Cervus elaphus, 6 fallow deer Dama dama and 4 wild boar Sus scrofa) in the same periods using IDM and RSF, respectively, in Doñana National Park (southern Spain) in order to explain and predict habitat use patterns for three studied species. Our results showed discrepancies between the two approaches, as they identified different predictors as being the most relevant to determine species intensity of use, and they predicted spatial patterns of habitat use with a contrasted level of concordance, depending on species and scale. Given these results and the characteristics of each approach, we suggested that although partly comparable interpretations can be obtained with both approaches, they are not equivalent but rather complementary. The combination of data from biologging and camera traps would, therefore, appear to be suitable for the development of an analytical framework with which to describe and characterise the habitat use processes of wildlife.

Parasites as indicators of habitat use by the schoolmaster (Lutjanus apodus) in the Mesoamerican Reef System

Habitat connectivity in coral-reef ecosystems partly depends on fish movements, and considerable effort has been made to understand their temporal and spatial patterns of habitat use. In the Caribbean, the schoolmaster, Lutjanus apodus, typically settle and grow up in mangroves and seagrass beds, migrating later to coral reefs. However, direct settlement on reefs, or permanent stay in mangroves, has also been observed in some localities, raising the question of whether schoolmasters could exhibit a wider repertoire of conditional, context-specific strategies. We investigated this issue in a new region, i.e., the Mesoamerican Reef System, based on parasite tagging. A total of 220 juvenile schoolmasters 1–2 yr old collected in estuarine mangroves, estuary sandy flats with marine influence, and reefs, in the region of Chetumal Bay were examined for metazoan parasites. This parasite fauna (36 taxa) significantly changed along the estuarine-marine gradient. The long-lived larvae of Contracaecum sp. type 2, Gorgorhynchoides bullocki, and Neoterranova sp. recruited very frequently in fish from estuarine mangroves. Infection patterns of these parasites suggested that (i) the fish collected in mangroves had settled and lived there until collection (1–2 years); (ii) the infected fish collected in sandy flats and reefs (a minimum of ca. 20% of the sample) had an estuarine origin. The digenean Hamacreadium mutabile had a clear marine affiliation and was never collected in estuarine fish. This suggests that ‘marine’ schoolmasters had not performed commuting excursions to estuarine waters, at least within the last months prior to collection. The small size of some fish infected with H. mutabile conforms to a direct settlement on reefs. In summary, the parasitological evidence provides mixed evidence of both habitat migration and residency of schoolmasters, also illustrating the potential of parasites to unveil patterns of habitat use by coral-reef fishes.

Habitat partitioning by mobile intertidal invertebrates of sandy beaches shifts with the tides

AbstractCoexistence of similar species can be influenced by the intensity of interspecific interactions, which often depends on the availability of limiting resources. Habitat availability varies strongly with tidal phase in many intertidal ecosystems, potentially affecting interspecific interaction strength, particularly for mobile species. Four closely related species of highly mobile intertidal detritivores (talitrid amphipods Megalorchestia californiana, M. corniculata, M. benedicti, M. minor) inhabit sandy beaches in southern California, where they consume wave‐cast macroalgal wrack originating on coastal reefs. Their coexistence suggests that mechanisms, such as niche separation, are operating to weaken competition among these species. To evaluate this possibility, we explored how tidal phase may mediate temporal and spatial patterns of habitat use among these closely related congeners. We hypothesized that neap tides that reduce intertidal habitat would strengthen temporal separation between species, whereas spatial separation would be greater during spring tides when more habitat is available. We investigated these questions during spring and neap tide phases using (1) comparisons of intertidal distributions of burrowed amphipods and (2) observations of surface activity of amphipods from pitfall traps and mesocosms. We found significant effects of tide phase and species identity on mean intertidal positions and separation of burrowed amphipods. Intertidal distributions of the four species overlapped during neap tide and were significantly separated during spring tide when more intertidal habitat was available. Surface activity patterns differed among species and were more widely separated in time during neap tide than during spring tide. Consequently, the cumulative activity time of all species on neap tides was twice that observed during spring tides. Our findings suggest that mobile intertidal species, like these sympatric talitrid amphipods, can avoid interspecific competition by shifting their activity patterns with tide phase and beach condition. As rising sea levels reduce beach habitat, interspecific competition among these important intertidal consumers may increasingly influence their behavior and coexistence.

Day and night use of habitats by northern pintails during winter in a primary rice-growing region of Iberia.

Loss of natural wetlands is a global phenomenon that has severe consequences for waterbird populations and their associated ecosystem services. Although agroecosystems can reduce the impact of natural habitat loss, drivers of use of such artificial habitats by waterbirds remain poorly understood. Using the cosmopolitan northern pintail Anas acuta as a model species, we monitored home-range and fine-scale resource selection across the agricultural landscape. Individuals were tracked using GPS-GSM transmitters, and a suite of environmental and landscape features were measured throughout the winter seasons. Spatial patterns of habitat use were analysed using generalized linear mixed effect models by integrating field-observations with GPS telemetry. All birds used rice fields as foraging grounds at night and commuted to an adjacent reservoir to roost during daylight. Home-ranges and maximum foraging distances of nocturnally foraging birds increased with decreasing availability of flooded fields, and were positively correlated with moonlight levels. Birds selected flooded rice paddies (water depth range: 9–21 cm) with standing stubble and substrate with pebbles smaller than 0.5 cm in diameter. Density of rice seeds, rice paddy size, and other environmental and landscape features did not emerge as significant predictors. Our findings indicate that nocturnal foraging of northern pintails within rice fields is driven primarily by straw manipulation, water level and substrate pebble size. Thus, the presence of standing stubble in flooded paddies with soft bottoms should be prioritized to improve foraging areas for dabbling ducks. These management procedures in themselves would not increase economic costs or affect rice production and could be applied for dabbling-duck conservation throughout the world.

Changes in spatial behaviour patterns by mangrove tree crabs following climate-induced range shift into novel habitat

Climate-mediated range shifts into eco-evolutionary novel habitats have the potential to alter the ecology and behaviour of range-expanding species. Of particular concern are behaviours that have a strong impact on the ecology and life history of expanding species. Behaviours that control the spatial patterns of habitat use may be particularly important. We examined site fidelity and foraging foray behaviour of the mangrove tree crab, Aratus pisonii, in its historic mangrove habitat and the recently colonized eco-evolutionary novel salt marsh. In the mangrove, A. pisonii showed both strong site fidelity to individual trees and a foraging pattern wherein they made foraging forays that decreased in frequency as their distance from the home tree increased; but they displayed neither behaviour in the salt marsh. Chemical cues from faeces appear to be the mechanism behind site fidelity in the mangrove and may suggest the mechanism for the loss of this behaviour in the salt marsh where substrate is regularly submerged, potentially preventing establishment of such cues. The loss of site fidelity may affect the foraging behaviour and predation risk of A. pisonii in the salt marsh, leading to a shift in its ecology and bioenergetics. As more species are forced to shift ranges into eco-evolutionary novel habitats, it is important to understand how this shift may affect their life history, behaviour and ecology in indirect ways.

Temporal and Spatial Patterns of Habitat Use by Juveniles of a Small Coastal Shark (Mustelus lenticulatus) in an Estuarine Nursery

Juvenile rig (Mustelus lenticulatus) were internally tagged with acoustic transmitters and tracked with acoustic receivers deployed throughout two arms of Porirua Harbour, a small (7 km2) estuary in New Zealand. Ten rig were tracked for up to four months during summer–autumn to determine their spatial and temporal use of the habitat. The overall goal was to estimate the size of Marine Protected Areas required to protect rig nursery areas from direct human impacts. Rig showed clear site preferences, but those preferences varied among rig and over time. They spent most of their time in large basins and on shallow sand and mud flats around the margins, and avoided deep channels. Habitat range increased during autumn for many of the rig. Only one shark spent time in both harbour arms, indicating that there was little movement between the two. Rig home ranges were 2–7 km2, suggesting that an effective MPA would need to cover the entire Porirua Harbour. They moved to outer harbour sites following some high river flow rates, and most left the harbour permanently during or soon after a river spike, suggesting that they were avoiding low salinity water. Rig showed strong diel movements during summer, although the diel pattern weakened in autumn. Persistent use of the same day and night sites indicates that diel movements are directed rather than random. Further research is required to determine the sizes of rig home ranges in larger harbours where nursery habitat is more extensive. Marine Protected Areas do not control land-based impacts such as accelerated sedimentation and heavy metal pollution, so integration of marine and terrestrial management tools across a range of government agencies is essential to fully protect nursery areas.

Multiple factors limit use of local sites by Elliot’s short-tailed shrews (Blarina hylophaga) in tallgrass prairie

Spatial variation in abundance has been attributed to habitat heterogeneity and patchiness. Our goal in this research was to understand what factors were associated with spatial patterns of habitat use by Elliot’s short-tailed shrews ( Blarina hylophaga Elliot, 1899) in tallgrass prairie. Our modeling efforts were based on 20 years (1981–2000) of presence–absence data for shrews at each of 20 stations (local site) along 14 permanent traplines on Konza Prairie Biological Station, Kansas, USA. A logistic model accurately predicted the presence of short-tailed shrews at a local site. Probability of shrew occurrence decreased as amount of precipitation decreased, slope steepness increased, grazing increased, or burned area within 500 m of a local site increased. However, when amount of precipitation was low, area burned was high, or grazing occurred, shrews were uncommon and responded little to the other variables. Numbers of shrews were negatively related only to numbers of deer mice ( Peromyscus maniculatus (Wagner, 1845)), a mouse that selects burned and grazed habitats that shrews avoid. Our observations suggest that multiple environmental factors limit use of local sites, whereas competition with other species does not. Our results can inform decisions related to conservation of biodiversity given management practices in this endangered ecosystem.

The spatial scaling of habitat selection by African elephants

1. Understanding and accurately predicting the spatial patterns of habitat use by organisms is important for ecological research, biodiversity conservation and ecosystem management. However, this understanding is complicated by the effects of spatial scale, because the scale of analysis affects the quantification of species-environment relationships. 2. We therefore assessed the influence of environmental context (i.e. the characteristics of the landscape surrounding a site), varied over a large range of scales (i.e. ambit radii around focal sites), on the analysis and prediction of habitat selection by African elephants in Kruger National Park, South Africa. 3. We focused on the spatial scaling of the elephants' response to their main resources, forage and water, and found that the quantification of habitat selection strongly depended on the scales at which environmental context was considered. Moreover, the inclusion of environmental context at characteristic scales (i.e. those at which habitat selectivity was maximized) increased the predictive capacity of habitat suitability models. 4. The elephants responded to their environment in a scale-dependent and perhaps hierarchical manner, with forage characteristics driving habitat selection at coarse spatial scales, and surface water at fine spatial scales. 5. Furthermore, the elephants exhibited sexual habitat segregation, mainly in relation to vegetation characteristics. Male elephants preferred areas with high tree cover and low herbaceous biomass, whereas this pattern was reversed for female elephants. 6. We show that the spatial distribution of elephants can be better understood and predicted when scale-dependent species-environment relationships are explicitly considered. This demonstrates the importance of considering the influence of spatial scale on the analysis of spatial patterning in ecological phenomena.

“Turtle watching” conservation guidelines: green turtle (Chelonia mydas) tourism in nearshore coastal environments

We propose a conservational opportunity for humans to ‘use’ the green turtle (Chelonia mydas) in a non-consumptive manner. Although the concept of a social safe-minimum standard analysis, as applied to the sustainability of tourism-dependent turtle watching, has focused on beach-nesting habitats, other tourist activities like diving and snorkelling also occur in shallow coastal habitats frequented by juvenile and adult turtles. When integrated over time, at a specific location, such tourism activities may compromise turtle physiology in a manner that limits conservation goals for the species and hence the tourism. We identify research insights that can be used to achieve a creatively managed tourism—one that allows tourists to observe turtles in their natural coastal habitat in a manner that is commensurate with functional turtle conservation. We propose management options loosely based on whale-watching: i.e. voluntary and/or mandatory regulations based on home-range studies that identify localized temporal and spatial patterns of habitat use exhibited by turtles. We recommend temporally- and spatially-dynamic stratified-random-design tours that exclude critical local (small-scale) habitat and include less-critical habitat on a randomized rotational basis. Practical guidelines for tour operators that are founded on turtle habitat-occupancy patterns may ensure expanded life-history conservation measures and sustainable turtle-watching tourism.

Patterns of Juvenile Habitat Use and Seasonality of Settlement by Permit, Trachinotus falcatus

Permit, Trachinotus falcatus are economically and ecologically important throughout their range of the Caribbean, subtropical and tropical western Atlantic, and Gulf of Mexico. Despite their economic importance, little is known about the biology and ecology of permit, and most existing information is from Florida. While sufficient information is available to paint a general picture of permit life history, details are lacking for most life stages. For the juvenile life stage, nursery habitats and size and age at settlement have not yet been defined. Although six distinct habitat types (medium energy and low energy windward beaches, leeward beaches, and windward, leeward, and lagoon interior mangrove shorelines) were sampled to determine spatial patterns of habitat use by early juvenile permit at Turneffe Atoll, Belize, Central America, and the Florida Keys, USA, 99% of juvenile permit were found along medium energy windward beaches, indicating their role as nursery habitat for this species. A sub-sample of juvenile permit from Florida was examined to estimate spawning date and age at settlement from otoliths. Size-frequency distributions and otolith age analysis indicate that larval duration is approximately 15 – 20 days, and settlement occurs year-round. Since permit in Florida spawn March through July, from March through September in Cuba, and from February through October in Belize, year-round settlement indicates population connectivity via larval transport. These results lay the foundation for future research on larval supply, population connectivity, and juvenile ecology, and will aid in the ongoing formulation of a conservation plan toward a sustainable fishery for permit.

Habitat selection and population regulation in temporally fluctuating environments.

Understanding and predicting the distribution of organisms in heterogeneous environments lies at the heart of ecology, and the theory of density-dependent habitat selection (DDHS) provides ecologists with an inferential framework linking evolution and population dynamics. Current theory does not allow for temporal variation in habitat quality, a serious limitation when confronted with real ecological systems. We develop both a stochastic equivalent of the ideal free distribution to study how spatial patterns of habitat use depend on the magnitude and spatial correlation of environmental stochasticity and also a stochastic habitat selection rule. The emerging patterns are confronted with deterministic predictions based on isodar analysis, an established empirical approach to the analysis of habitat selection patterns. Our simulations highlight some consistent patterns of habitat use, indicating that it is possible to make inferences about the habitat selection process based on observed patterns of habitat use. However, isodar analysis gives results that are contingent on the magnitude and spatial correlation of environmental stochasticity. Hence, DDHS is better revealed by a measure of habitat selectivity than by empirical isodars. The detection of DDHS is but a small component of isodar theory, which remains an important conceptual framework for linking evolutionary strategies in behavior and population dynamics.

Movements of juvenile black sea bass Centropristis striata (Linnaeus) in a southern New Jersey estuary

Tag–recapture experiments of black sea bass Centropristis striata (Linnaeus) were conducted in the Great Bay estuary in southern New Jersey U.S.A. to examine habitat fidelity, movements, and growth for recently settled individuals in the first summer ( n=337, 34–106 mm TL) and the following spring ( n=367, 43–111 mm TL) in order to determine the temporal and spatial patterns of habitat use. During the 15-month (March 1992–July 1993) study, there were 225 recaptures of 180 fish up to 121 d after their initial release. Recapture frequency was high (31%) for fish released in spring and summer and recently settled fish (21%) released in summer and indicated a high degree of habitat fidelity for both of those age groups during those seasons. Almost all recaptures (99%) were made within 30 m of the release site, and of the 35 fish that were recaptured at least twice, 46% were recaptured at the original capture site. Growth, based on recaptured fish, was fastest during the summer (0.74 mm d −1), but averaged 0.45 mm d −1 from spring through fall. The low rate of recapture, as well as shorter recapture intervals, during the fall are consistent with a movement into the ocean at that time. Estimates of total loss (=mortality+emigration) of young-of-the-year released in summer were higher during the first 18 days (0.187 d −1) following their release than during subsequent days (0.013 d −1 up to day 88), and averaged 0.033 d −1 for the summer and early fall. In summary, some proportion of the juvenile black sea bass population is resident in polyhaline, subtidal estuarine habitats in the summer and in the spring when they are growing the fastest. As a result, habitat-specific responses during these periods may have important implications for survival and subsequent recruitment to the adult population for this species.

Predator‐prey system structure in patchy and ephemeral phytotelmata: Aquatic communities in small aroid axils

AbstractMechanisms allowing the persistence of an aquatic predator‐prey system in tiny pools (the mean ca. 0.5 ml) held by taro axils were analyzed from the viewpoint of temporal and spatial patterns of habitat use. Predatory larvae of a mosquito Topomyia tipuliformis concentrated in young axils, while 9 other taxa utilized both young and old axils or concentrated more in older axils. The total prey density was lower in axils with the predator but the density of each prey taxon (except for a few cases) and the number of prey taxa did not differ between axils with and without predators. This indicates that T. tipuliformis is a general predator and does not influence prey community organization through selective removal of particular prey taxa. Inter‐axil distribution of T. tipuliformis was aggregated in the first instar but uniform in the third and fourth instars due to intraspecific cannibalism, which assures the survival of a single individual under short food supply. Distributions of prey taxa were mostly aggregated, fitting the negative binomial distribution. Thirty seven out of 45 associations of 10 taxa were independent with 3 negative (between the predator and some late‐colonizing prey) and 5 positive (between some prey taxa) associations. Probabilistic refuges (produced by independent aggregated distributions) reduced interspecific encounters which may result in competition and predation, and thus probably facilitated prey coexistence. There was no evidence for the importance of predation in structuring the prey community. This system may be prey‐dominated in that predator persistence depends on prey community existence but prey community structure depends less on predation.

Comparative population ecology of the dragonflies Libellula lydia and Libellula luctuosa (Odonata: Libellulidae)

Temporal and spatial patterns of habitat use, population size structure, and survivorship were compared over three generations of Libellula lydia and Libellula luctuosa in a small pond in Indiana. The two species were univoltine, had similar phenologies, and converged on the same within-pond habitats. There was little evidence for any spatial and (or) temporal habitat partitioning that might be expected between such morphologically and ecologically similar species. Larval populations of each species were highly size structured because oviposition and hatching were extended over 3 months in summer. Intraspecific size differences were greater than those frequently reported to accommodate interspecific coexistence. Thus, intraspecific resource partitioning and cannibalism should have an important effect on population dynamics. Both similar and disparate interspecific size combinations frequently co-occurred in time and space so that competition and predation should simultaneously affect coexistence. Larval mortality was high in late summer and fall, negligible in winter, and high again in spring. Fewer than 10% of either species survived to emerge from the pond. Interodonate predation is a likely source of much of this larval mortality, given that other odonates are among the most abundant large predators in fishless ponds.