Spatial Ecology

Interpreting Space Use and Behavior of Blue Tang, Acanthurus coeruleus , in the Context of Habitat, Density, and Intraspecific Interactions

by Joshua Drew

Internalising the costs of fragmentation and nutrient deposition in spatial planning: Extending a decision support tool for the Netherlands

by Maarten Hilferink

Positive interactions between desert granivores: localized facilitation of harvester ants by kangaroo rats

by Andrew Edelman

Edelman, A.J. 2012. Positive interactions between desert granivores: localized facilitation of harvester ants by kangaroo rats. PLoS ONE 7(2): e30914. doi:10.1371/journal.pone.0030914

Evidence of social communities in a spatially structured network of a free-ranging shark species

by Johann Mourier

Large, solitary, marine predators such as sharks have been observed to aggregate at specific areas. Such aggregations... more Large, solitary, marine predators such as sharks have been observed to aggregate at specific areas. Such aggregations are almost certainly driven by foraging and behavioural strategies making space for diverse spatial organizations. Reef-associated shark species often show strong patterns of site fidelity that could be viewed as a prerequisite for sociality. However, there is limited empirical evidence that such aggregations are driven by intrinsic social factors. Association data for blacktip reef sharks, Carcharhinus melanopterus, were obtained from photoidentification surveys conducted in Moorea coral reefs (French Polynesia). We adapted a social network approach to demonstrate evidence of four main communities and two subcommunities within the population. We confronted the resulting structure with candidate explanatory variables. Sharks formed spatial groups characterized by nonrandom and long-term associations, despite opportunities for social relationships to develop between communities. Sex and length
of sharks tended to influence assortment at the population and community levels. Individual space use also explained community structure, although spatial assortment was globally weaker than random expectations, suggesting that observed associations were not an artefact of the sampling design or spatial distribution of individuals. We conclude that the observed grouping patterns not only resulted from passive aggregations for specific resources, but rather the communities developed from an active choice of individuals as a sign of sociability. Individual preferences and adaptation to local conditions, as well as
demographic, ecological and anthropogenic factors, may explain the social variability between communities. This suggests that a stable grouping strategy may confer substantial benefits in this marine
predator.

Fisher, J.T., B. Anholt, and J.P. Volpe. 2011. Body mass explains characteristic scales of habitat selection in terrestrial mammals. Ecology and Evolution 1(4): 517-528.

by Jason T. Fisher

Niche theory in its various formsis based on those environmental factors that permit species persistence, but less... more Niche theory in its various formsis based on those environmental factors that permit species persistence, but less work has focused on defining the extent, or size, of a species’ environment: the area that explains a species’ presence at a point in space. We proposed that this habitat extent is identifiable from a characteristic scale of habitat selection, the spatial scale at which habitat best explains species’ occurrence.
We hypothesized that this scale is predicted by body size.We tested this hypothesis on 12 sympatric terrestrial mammal species in the Canadian RockyMountains. For each species, habitat models varied across the 20 spatial scales tested. For six species, we found a characteristic scale; this scale was explained by species’ body mass in a quadratic relationship. Habitat measured at large scales best-predicted habitat
selection in both large and small species, and small scales predict habitat extent in medium-sized species. The relationship between body size and habitat selection scale implies evolutionary adaptation to landscape heterogeneity as the driver of scale-dependent habitat selection.

Cross-scale variation in the density and spatial distribution of an Amazonian non-timber forest resource

by Pete Newton

Authors: Newton, P., Peres C.A., Desmoulière, S.J.M., Watkinson, A.R.
Journal: Forest Ecology and Management
Volume: 276
Pages: 41-51

Successful management of tropical forest resources depends upon an understanding of their patterns of density and... more Successful management of tropical forest resources depends upon an understanding of their patterns of density and spatial distribution, since these affect the potential for harvesting. The variation in these patterns across different spatial scales has rarely been explored. We assessed the extent to which different spatial scales are useful in understanding resource distribution, using the example of an economically significant tropical tree genus, Copaifera, which is valued across Brazilian Amazonia for its medicinal oleoresin. We mapped the spatial distribution of Copaifera trees at three nested spatial scales: basin-wide (across Brazilian Amazonia), landscape (across two contiguous extractive reserves) and local (within a 100-ha plot). Using data from our own study and an Amazon-wide forest inventory (Projeto RADAMBRASIL), we quantified the population distribution, density and size structure at the genus and species level at all three scales, relating these to two environmental variables – forest type and elevation. Spatial statistics were used to further characterize the resource at the landscape and local levels. The distribution, density and adult population structure differed between species and forest types at all three spatial scales. Overall tree densities ranged from 0.37 ha–1 (basin-wide scale) to 1.13 ha–1 (local scale) but varied between forest types, with várzea containing a Copaifera tree density just 43% of that in terra firme forest at the landscape scale. Spatial distribution analyses showed significant clumping of some species, especially C. multijuga which averaged 61 m between neighbouring trees. We compare our cross-scale density estimates and discuss the relative merits of studying the distribution of non-timber forest products (NTFP) at more than one spatial scale. Our results have implications for the management and extraction of this important Amazonian forest resource.

Spatial, temporal and economic constraints to the commercial extraction of a non-timber forest product: copaíba (Copaifera spp.) oleoresin in Amazonian reserves

by Pete Newton

Authors: Newton, P., Watkinson, A.R., Peres, C.A.
Journal: Economic Botany
DOI: 10.1007/s12231-012-9198-z

The increasing prevalence of government- and NGO-sponsored programs to encourage commercial non-timber forest product... more The increasing prevalence of government- and NGO-sponsored programs to encourage commercial non-timber forest product (NTFP) extractivism in the humid tropics has highlighted the need for ecological and socioeconomic appraisal of the viability of extractive industries. We adopted a novel, integrative approach to examining NTFP resource potential and produced credible landscape-scale estimates of the projected value of an economically important Amazonian NTFP, the medicinal oleoresin of Copaifera trees, within two large contiguous extractive reserves in Brazilian Amazonia. We integrated results derived from previous spatial ecology and harvesting studies with socioeconomic and market data, and mapped the distribution of communities within the reserves. We created anisotropic accessibility models which determined the spatial and temporal access to Copaifera trees in permanently unflooded (terra firme) and seasonally-flooded (várzea) forest. Just 64.9% of the total reserve area was accessible, emphasizing the distinction between the actual resource stock and that which is available to extractors. The density of productive tree species was higher in várzea forest but per tree productivity was greater in terra firme forest, resulting in similar estimates of oleoresin yield per unit area (64 – 67 ml ha–1) in both forest types. A greater area of várzea forest was accessible within shorter travel times of ≤250 min; longer travel times allowed access to increasingly greater volumes of oleoresin from terra firme forest. The estimated total volume of oleoresin accessible within the two reserves was 38,635 liters for an initial harvest, with projected offtake for a subsequent harvest falling to 8,274 liters. A household that extracted just two liters of oleoresin per month could generate 5% of its mean income; market data suggested that certification could increase the value of the resource five-fold. Our approach is valuable in that it incorporates a range of methodologies and quantitatively accounts for the numerous constraints to the commercial viability of NTFP extraction.

Faith, Morality and Mortality: The Ecological Impact of Religion on Population Health

by Todd Matthews

Co-authored with Troy C. Blanchard, John P. Bartkowski and Kent R. Kerley - Social Forces (2008)

First results of feral cats(Felis catus) monitored with GPS collars in New Zealand

by Phil Seddon

The terminology of metacommunity ecology

by Tadeu Siqueira

Article co-authored with Amanda K. Winegardner, Brittany K. Jones, Ingrid S.Y. Ng and Karl Cottenie. Published in Trends in Ecology & Evolution, 27, 253–254.

Modeling spatial patterns in fisheries bycatch: improving bycatch maps to aid fisheries management

by Michelle Sims

Ecological applications, 2008

Fisheries bycatch, or incidental take, of large vertebrates such as sea turtles, seabirds, and marine mammals, is a... more Fisheries bycatch, or incidental take, of large vertebrates such as sea turtles, seabirds, and marine mammals, is a pressing conservation and fisheries management issue. Identifying spatial patterns of bycatch is an important element in managing and mitigating bycatch occurrences. Because bycatch of these taxa involves rare events and fishing effort is highly variable in space and time, maps of raw bycatch rates (the ratio of bycatch to fishing effort) can be misleading. Here we show how mapping bycatch can be enhanced through the use of Bayesian hierarchical spatial models. We compare model-based estimates of bycatch rates to raw rates. The model-based estimates were more precise and fit the data well. Using these results, we demonstrate the utility of this approach for providing information to managers on bycatch probabilities and cross-taxa bycatch comparisons. To illustrate this approach, we present an analysis of bycatch data from the U.S. gill net fishery for groundfish in the northwest Atlantic. The goals of this analysis are to produce more reliable estimates of bycatch rates, assess similarity of spatial patterns between taxa, and identify areas of elevated risk of bycatch.


Read More: http://www.esajournals.org/doi/abs/10.1890/07-0685.1?journalCode=ecap

Site variation in spatial aggregation and phorophyte preference in Psychilis monensis (Orchidaceae)

by Susan Aragon

Spatial structure, environmental heterogeneity, and population dynamics: analysis of the coupled logistic map

by Gordon Fox

Regulation of animal size by eNPP, Bergmann’s rule,

by Steve Wolverton

Michael A. Huston and Steve Wolverton

Bergmann's rule, which proposes a heat-balance explanation for the observed latitudinal gradient of increasing animal... more Bergmann's rule, which proposes a heat-balance explanation for the observed latitudinal gradient of increasing animal body size with increasing latitude, has dominated the study of geographic patterns in animal size since it was first proposed in 1847. Several critical reviews have determined that as many as half of the species examined do not fit the predictions of Bergmann's rule. We have proposed an alternative hypothesis for geographic variation in body size based on food availability, as regulated by the net primary production (NPP) of plants, specifically NPP during the growing season, or eNPP (ecologically and evolutionarily relevant NPP). Our hypothesis, “the eNPP rule,” is independent of latitude and predicts both spatial and temporal variation in body size, as well as in total population biomass, population growth rates, individual health, and life history traits of animals, including humans, wherever eNPP varies across appropriate scales of space or time. In the context of a revised interpretation of the global patterns of NPP and eNPP, we predict contrasting latitudinal correlations with body size in three distinct latitudinal zones. The eNPP rule explains body-size patterns that are consistent with Bergmann's rule, as well as two distinct types of contradictions of Bergmann's rule: the lack of latitudinal patterns within the tropics, and the decline in body size above approximately 60° latitude. Both types of contradictions of Bergmann's rule are consistent with the eNPP rule, as are a wide range of other phenomena.

Beyond the Mean Field in Host-Pathogen Spatial Ecology

by Andreas Gros

Co-authored with Blake C. Stacey and Yaneer Bar-Yam

Spatial extent---the possibility that what happens at point A cannot immediately affect what happens at point B---is a... more Spatial extent---the possibility that what happens at point A cannot immediately affect what happens at point B---is a complicating factor in mathematical biology, as it creates the opportunity for spatial non-uniformity. This non-uniformity must change our understanding of evolutionary dynamics, as the same organism in different places can have different expected evolutionary outcomes. Since organism origins and fates are both determined locally, we must consider heterogeneity explicitly to determine its effects. We use simulations of spatially extended host-pathogen and predator-prey ecosystems to reveal the limitations of standard mathematical treatments of spatial heterogeneity. Our model ecosystem generates heterogeneity dynamically; an adaptive network of hosts on which pathogens are transmitted arises as an emergent phenomenon. The structure and dynamics of this network differ in significant ways from those of related models studied in the adaptive-network field. We use a new technique, organism swapping, to test the efficacy of both simple approximations and more elaborate moment-closure methods, and a new measure to reveal the timescale dependence of invasive-strain behavior. Our results demonstrate the failure not only of the most straightforward ("mean field") approximation, which smooths over heterogeneity entirely, but also of the standard correction ("pair approximation") to the mean field treatment. In spatial contexts, invasive pathogen varieties can prosper initially but perish in the medium term, implying that the concepts of reproductive fitness and the Evolutionary Stable Strategy have to be modified for such systems.

Uncertainty propagation in chained web based modeling services: the case of eHabitat

by Gregoire Dubois

Skøien, J., M. Schulz, G. Dubois, R. Jones, G.B.M. Heuvelink, D. Cornford (2011). Uncertainty propagation in chained web based modeling services: the case of eHabitat.  In: “Innovation in sharing environmental observations and information. Proceedings of EnviroInfo 2011, 25th International Conference Environmental Informatics”. W. Pillmann, S. Schade and P. Smits (Eds), pp: 46-58, 5-7 October 2011, Ispra, Italy.

eHabitat is a Web Processing Service (WPS) designed to compute the likelihood of finding ecosystems with similar... more eHabitat is a Web Processing Service (WPS) designed to compute the likelihood of finding ecosystems with similar conditions. Starting from a reference area, typically a protected area, one can compute for each pixel of a region of interest the probability to find a combination of a set of predefined environmental indicators that is similar to the one observed in the reference area using the Mahalanobis distances to the mean and covariance of these indicators. Inputs to the WPS are thus the reference polygon and a set of environmental indicators, typically thematic geospatial “layers”, which can be discovered using standardised catalogues. The outputs can be tailored to specific end user needs in terms of data format and data resolution. Because these input layers can range from geophysical data captured through remote sensing to socio-economical indicators, eHabitat is exposed to a broad range of different types and levels of uncertainties which are inevitably propagated through the service (see e.g. Heuvelink, 1998). Potentially chained to other services to perform ecological forecasting, for example, eHabitat would be an additional component further propagating uncertainties from a potentially long chain of model services. Such a configuration of distributed data and model services as envisaged by initiatives such as the “Model Web” from the Group on Earth Observations, to be of any use to policy or decision makers, requires from users clear information on data uncertainties. The development of such an Uncertainty-Enabled Model Web is the scope of the UncertWEB project which is promoting interoperability between data and models with quantified uncertainty and building a framework on existing open, international standards. It is the objective of this paper to illustrate a few key ideas behind UncertWeb using eHabitat to discuss the main types of uncertainties the WPS has to deal with and to present the benefits of the use of the UncertWeb framework.

Merleau-Ponty, Perception, and Environmental Embodiment: Implications for Architectural and Environmental Studies

by David Seamon

chapter prepared for Carnal Echoes: Merleau-Ponty and the Flesh of Architecture, Rachel McCann and Patricia M. Locke, editors, forthcoming, 2012 or 2013. © David Seamon 2010.

In this chapter, I draw on Merleau-Ponty’s philosophy to explore environmental embodiment—the various lived ways,... more In this chapter, I draw on Merleau-Ponty’s philosophy to explore environmental embodiment—the various lived ways, sensorily and motility-wise, that the body in its pre-reflective perceptual presence engages and synchronizes with the world at hand, especially its architectural and environmental aspects. First, I consider Merleau-Ponty’s interpretation of perception, giving particular attention to his claim that perception involves a lived dynamic between perceptual body and world such that aspects of the world—for example, the heavy hardness of a granite block or the cool smoothness of a chrome railing—are known because they immediately evoke in the lived body their experienced qualities.

Second, I consider the architectural and environmental significance of what Merleau-Ponty calls body-subject—pre-reflective corporeal awareness expressed through action and typically in sync with and enmeshed in the physical world in which the action unfolds. I focus on the taken-for-granted sensibility of body-subject to manifest in extended ways over time and space. I ask how routine actions and behaviors of individuals coming together regularly in an environment can transform that environment into a place with a unique dynamic and character—a lived situation I term place ballet. For both perception and body-subject, I consider how qualities of the physical and designable world—for example, materiality, form, and spatiality—contribute to the lived body’s engagement with and actions in the world.

Spatial Patterns of Pinyon–Juniper Woodland Expansion in Central Nevada

by Emanuele Lingua

Published in Rangeland Ecology and Management, 2007. Co-authored with Peter J. Weisberg, Rekha Pillai

Explaining spatial variability in stream habitats using both natural and management-influenced landscape predictors

by Blake Feist

Anlauf, KJ, DW Jensen, KM Burnett, EA Steel, K Christiansen, JC Firman, BE Feist & DP Larsen (In Press) Aquatic Conservation: Marine and Freshwater Ecosystems

1. The distribution and composition of in-stream habitats are reflections of landscape scale geomorphic and climatic... more 1. The distribution and composition of in-stream habitats are reflections of landscape scale geomorphic and climatic controls. Correspondingly, Pacific salmon (Oncorhynchus spp.) are largely adapted to and constrained by the quality and complexity of those in-stream habitat conditions. The degree to which lands have been fragmented and managed can disrupt these patterns and affect overall habitat availability and quality.

2. Eleven in-stream habitat features were modeled as a function of landscape composition. A total of 121 stream reaches within coastal watersheds of Oregon were modeled. For each habitat feature, three linear regression models were applied in sequence; final models were composed of the immutable and management-influenced landscape predictors that best described the variability in stream habitat.

3. Immutable landscape predictors considered proxies for stream power described the majority of the variability seen in stream habitat features. Management- influenced landscape predictors, describing the additional anthropogenic effects beyond that which was inherently entwined with the immutable predictors, explained a sizeable proportion of variability. The largest response was seen in wood volume and pool frequency.

4. By using a sequential linear regression analysis, management-influenced factors were able to be segregated from natural gradients in order to identify those stream habitat features that may be more sensitive to land use pressures. Our results contribute to the progressing notion that the conservation of freshwater resources is best accomplished by investigating and managing stream systems from a landscape perspective.

Landscape ecotoxicology of coho salmon spawner mortality in urban streams

by Blake Feist

Feist, BE, ER Buhle, P Arnold, JW Davis & NL Scholz (2011) Public Library of Science ONE 6(8): e23424. doi:10.1371/journal.pone.0023424

In the Pacific Northwest of the United States, adult coho salmon (Oncorhynchus kisutch) returning from the ocean to... more In the Pacific Northwest of the United States, adult coho salmon (Oncorhynchus kisutch) returning from the ocean to spawn in urban basins of the Puget Sound region have been prematurely dying at high rates (up to 90% of the total runs) for more than a decade. The current weight of evidence indicates that coho deaths are caused by toxic chemical contaminants in land-based runoff to urban streams during the fall spawning season. Non-point source pollution in urban landscapes typically originates from discrete urban and residential land use activities. In the present study we conducted a series of spatial analyses to identify correlations between land use and land cover (roadways, impervious surfaces, forests, etc.) and the magnitude of coho mortality in six streams with different drainage basin characteristics. We found that spawner mortality was most closely and positively correlated with the relative proportion of local roads, impervious surfaces, and commercial property within a basin. These and other correlated variables were used to identify unmonitored basins in the greater Seattle metropolitan area where recurrent coho spawner die-offs may be likely. This predictive map indicates a substantial geographic area of vulnerability for the Puget Sound coho population segment, a species of concern under the U.S. Endangered Species Act. Our spatial risk representation has numerous applications for urban growth management, coho conservation, and basin restoration (e.g., avoiding the unintentional creation of ecological traps). Moreover, the approach and tools are transferable to areas supporting coho throughout western North America.