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271.
Amandine Gasc Benjamin L. Gottesman Dante Francomano Jinha Jung Mark Durham Jason Mateljak Bryan C. Pijanowski 《Landscape Ecology》2018,33(8):1399-1415
Context
While remote sensing imagery is effective for quantifying land cover changes across large areas, its utility for directly assessing the response of animals to disturbance is limited. Soundscapes approaches—the recording and analysis of sounds in a landscape—could address this shortcoming.Objectives
In 2011, a massive wildfire named “the Horseshoe 2 Burn” occurred in the Chiricahua National Monument, Arizona, USA. We evaluated the impact of this wildfire on acoustic activity of animal communities.Methods
In 2013, soundscape recordings were collected over 9 months in 12 burned and 12 non-burned sites in four ecological systems. The seasonal and diel biological acoustic activity were described using the “Bioacoustic Index”, a detailed aural analysis of sound sources, and a new tool called “Sonic Timelapse Builder” (STLB).Results
Seasonal biophony phenology showed a diurnal peak in June and a nocturnal peak in October in all ecological systems. On June mornings, acoustic activity was lower at burned than at non-burned sites in three of four ecological systems, due to a decreased abundance of cicadas directly impacted by the death of trees. Aural analyses revealed that 55% of recordings from non-burned sites contained insect sounds compared to 18% from burned sites. On October nights, orthopteran activity was more prevalent at some burned sites, possibly due to post-fire emergence of herbaceous.Conclusions
Soundscape approaches can help address long-term conservation issues involving the responses of animal communities to wildfire. Acoustic methods can serve as a valuable complement to remote sensing for disturbance-based landscape management.272.
Erick M. G. Cordeiro James F. Campbell Thomas W. Phillips Kimberly A. With 《Landscape Ecology》2018,33(11):1881-1894
Context
Although animal movement behaviors are influenced by spatial heterogeneity, such behaviors can also generate spatial heterogeneity via interactions with the emergent spatial structure and other individuals (i.e., the social landscape).Objective
Elucidate the behavioral and ecological mechanisms of pattern formation in a homogeneous resource landscape.Methods
We analyzed the movement pathways and space-use patterns of the lesser grain borer (Rhyzopertha dominica) within homogeneous resource landscapes (wheat kernels). Experimental trials consisted of individual beetles foraging alone or paired with a member of the same or different sex.Results
We identified two sources of pattern formation: (1) beetles were attracted to areas where they or another beetle had previously fed, leading to increased patchiness via positive reinforcement; and (2) the presence of conspecifics affected whether and at what scales patchiness occurred. Solitary males had lower rates of movement and less tortuous pathways than solitary females, but both sexes generated fine-scale patchiness in the resource distribution. Patchy resource landscapes were also generated by male–female pairs, but not by same-sex pairings. Paired females in particular exhibited significantly greater daily net displacements and more random space use than solitary females.Conclusions
Pattern formation is a complex process, even in a relatively simple, homogeneous resource landscape. In particular, patterns created by individuals when foraging alone versus in pairs underscores how social interactions can fundamentally alter the resultant pattern of heterogeneity that emerges in resource landscapes.273.
Natural ecosystems are life-supporting systems providing diverse ecosystem services (ESs) and benefits to human societies:
e.g., food and clean water, recreation opportunities or climate regulation. The contribution of natural and semi-natural ecosystems
to the provision of such services depends to a large extent on vegetation structure and composition, which, in turn, change
as a result of interactions between human decisions about land management, and spontaneous biological and environmental processes.
Rational management of these dynamic ecosystems requires an ability to predict short- and long-term effects of management
decisions on the desired ESs. The vegetation then contributes to, and modifies, the products and services obtained from the
land. We applied mathematical modeling to study these complex relationships. We developed a model for a Mediterranean ecosystem
which predicts the dynamics of multiple services in response to management scenarios, mediated by vegetation changes. Six
representative ESs representing different groups were selected, based on available scientific information, for a detailed
study: (1) density of geophytes, (2) potential contribution to honey production, (3) energy density of fleshy fruits foraged
by birds, (4) forage for goats, (5) forage for cattle, and (6) carbon retention in woody plants. Mean contributions to each
service by different vegetation cover types were estimated, and the overall service provided by the site was calculated as
a weighted mean of these contributions. Services were measured in their appropriate units and subsequently standardized to
a percentage of the maximum value observed in the study area. We attempted to combine all studied ESs, despite their different
nature, into one “ESs basket”. This paper presents the dynamics of simulated vegetation composition and values of services
in response to management scenarios involving grazing, fire and their combinations. Our approach can help land managers to
evaluate alternative management scenarios by presenting the “services basket” obtained from the entire managed area. 相似文献
274.
Protection of biodiversity and ecosystem functions requires a better understanding of spatial diversity. Here we studied diversity
patterns of true bugs and saproxylic beetles, sampled in 28 forest stands of southern Germany, using a hierarchical nested
design of five increasingly broader spatial levels: trap location, stratum, forest stand, forest site, and ecoregion. We predicted
that: (1) for large body-sized species (as a surrogate for highly mobile species) and host generalist species (low host specificity),
the proportion of β-diversity decreases from small to large spatial scales; and (2) the differences between trait-based functional
guilds in the proportion of β-diversity increase with increasing weighting of more-abundant species. Our results indicated
that the ecoregion level is the most important diversity scale for both taxa and among functional guilds sampled, followed
by the forest stand level. Specialized species were more strongly affected on the ecoregion level than generalist species.
Differences in the proportion of β-diversity between functional guilds increased with increasing weighting of abundant species.
The β-diversity patterns based on body size and host specificity were similar for true bugs, but partly contrasting for saproxylic
beetles. Our results suggest that (1) future conservation schemes should focus on establishing new conservation sites in new
ecoregions, rather than on enlarging existing protected areas; (2) host specificity might be a more meaningful trait than
body size to be considered in biodiversity studies; and (3) common conservation approaches restricted to only large, conspicuous,
but rare species might result in a mismatch of important biodiversity scales. 相似文献
275.
276.
Paul Miguet Heather B. Jackson Nathan D. Jackson Amanda E. Martin Lenore Fahrig 《Landscape Ecology》2016,31(6):1177-1194
Context
Landscape ecologists are often interested in measuring the effects of an environmental variable on a biological response; however, the strength and direction of effect depend on the size of the area within which the environmental variable is measured. Thus a central objective is to identify the optimal spatial extent within which to measure the environmental variable, i.e. the “scale of effect”.Objectives
Our objectives are (1) to provide a comprehensive summary of the hypotheses concerning what determines the scale of effect, (2) to provide predictions that can be tested in empirical studies, and (3) to show, with a review of the literature, that most of these predictions have so far been inadequately tested.Methods
We propose 14 predictions derived from five hypotheses explaining what determines the scale of effect, and review the literature (if any) supporting each prediction. These predictions involve five types of factors: (A) species traits, (B) landscape variables, (C) biological responses (e.g. abundance vs. occurrence), (D) indirect influences, and (E) regional context of the study. We identify methodological issues that hinder estimation of the scale of effect.Results
Of the 14 predictions, only nine have been tested empirically and only five have received some empirical support. Most support is from simulation studies. Empirical evidence usually does not support predictions.Conclusions
The study of the spatial scale at which landscape variables influence biological outcomes is in its infancy. We provide directions for future research by clarifying predictions concerning the determinants of the scale of effect.277.
Anne Villemey William E. Peterman Murielle Richard Annie Ouin Inge van Halder Virginie M. Stevens Michel Baguette Philip Roche Frédéric Archaux 《Landscape Ecology》2016,31(7):1629-1641
Context
Anthropogenic activities readily result in the fragmentation of habitats such that species persistence increasingly depends on their ability to disperse. However, landscape features that enhance or limit individual dispersal are often poorly understood. Landscape genetics has recently provided innovative solutions to evaluate landscape resistance to dispersal.Objectives
We studied the dispersal of the common meadow brown butterfly, Maniola jurtina, in agricultural landscapes, using a replicated study design and rigorous statistical analyses. Based on existing behavioral and life history research, we hypothesized that the meadow brown would preferentially disperse through its preferred grassy habitats (meadows and road verges) and avoid dispersing through woodlands and the agricultural matrix.Methods
Samples were collected in 18 study landscapes of 5 × 5 km in three contrasting agricultural French regions. Using circuit theory, least cost path and transect-based methods, we analyzed the effect of the landscape on gene flow separately for each sex.Results
Analysis of 1681 samples with 6 microsatellites loci revealed that landscape features weakly influence meadow brown butterfly gene flow. Gene flow in both sexes appeared to be weakly limited by forests and arable lands, whereas grasslands and grassy linear elements (road verges) were more likely to enhance gene flow.Conclusion
Our results are consistent with the hypothesis of greater dispersal through landscape elements that are most similar to suitable habitat. Our spatially replicated landscape genetics study allowed us to detect subtle landscape effects on butterfly gene flow, and these findings were reinforced by consistent results across analytical methods.278.
Context
Land-use change can reduce and isolate suitable habitat generating spatial variation in resource availability. Improving species distribution models requires a multi-scale understanding of resource requirements and species’ sensitivities to novel landscapes.Objectives
We investigated how the spatial distribution of supplementary habitats (permanent wetlands), urbanization, water depths, and distribution of a key prey species (muskrat; Ondatra zibethicus) influence occupancy dynamics of American mink (Neovison vison). Although mink are widespread across North America and a destructive invasive species in Europe, South America, and Asia, we have a limited understanding of factors affecting their spatial distribution.Methods
We used 6 years of presence–absence data (2007–2012) to evaluate occupancy dynamics of mink at 58–90 stream sites along an urbanization gradient in Illinois, USA. We predicted negative relationships between stream occupancy and urban land cover and distance from permanent wetlands, and positive associations with muskrat presence, water depth, and riparian zone width.Results
Contrary to our hypothesis, stream sites closer to permanent wetlands had lower occupancy and colonization rates for mink. Occupancy and colonization rates were higher at sites with deeper water, and colonization rates were related negatively to urbanization. Mink were more likely to leave stream habitat if muskrats were not present and permanent wetlands were nearby.Conclusion
Factors interplaying across multiple scales influenced occupancy dynamics of mink in stream habitat in a highly modified landscape. Our results highlight the importance of considering both direct measures of prey availability and the spatial distribution of supplementary habitats to improve habitat-selection models for carnivores.279.
Brad C. Timm Kevin McGarigal Samuel A. Cushman Joseph L. Ganey 《Landscape Ecology》2016,31(6):1209-1225
Context
Organisms commonly respond to their environment across a range of scales, however many habitat selection studies still conduct selection analyses using a single-scale framework. The adoption of multi-scale modeling frameworks in habitat selection studies can improve the effectiveness of these studies and provide greater insights into scale-dependent relationships between species and specific habitat components.Objectives
Our study assessed multi-scale nest/roost habitat selection of the federally “Threatened” Mexican spotted owl (Strix occidentalis lucida) in northern Arizona, USA in an effort to provide improved conservation and management strategies for this subspecies.Methods
We conducted multi-scale habitat modeling to assess habitat selection by Mexican spotted owls using survey data collected by the USFS. Each selected covariate was included in multi-scale models at their “characteristic scale” and we used an all-subsets approach and model selection framework to assess habitat selection.Results
The “characteristic scale” identified for each covariate varied considerably among covariates and results from multi-scale models indicated that percent canopy cover and slope were the most important covariates with respect to habitat selection by Mexican spotted owls. Multi-scale models consistently outperformed their analogous single-scale counterparts with respect to the proportion of deviance explained and model predictive performance.Conclusions
Efficacy of future habitat selection studies will benefit by taking a multi-scale approach. In addition to potentially providing increased explanatory power and predictive capacity, multi-scale habitat models enhance our understanding of the scales at which species respond to their environment, which is critical knowledge required to implement effective conservation and management strategies.280.
Luciana Signorelli Rogério P. Bastos Paulo De MarcoJr Kimberly A. With 《Landscape Ecology》2016,31(9):1997-2012