This book is divided into three sections: (a) Relevant Temporal Theory (Chapters 15), (b) Statistics of Time (Chapters 6 and 7), and (c) Temporally Focused Case Studies (Chapters 8-14). In the first chapter of section 1, Relevant Temporal Theory, Bissonette makes the argument that an enhanced understanding of animal response to resource availability may be possible if two elements are added to the standard, single currency quantity approach. The first element relates to measuring resource quality and requires adding an additional currency to our ecological ledger book. The second element incorporates the idea of temporal discontinuity in resource quantity and quality. Bissonette suggests that a broader incorporation of these two elements into wildlife ecology will enhance our understanding of animal response to resource availability at both small and larger spatial extents. In the second chapter, Ostfeld and Keesing argue that pulses of resources are major bottom-up drivers in ecological systems, leading to a suite of responses by consumers that interact with those resources either directly or indirectly. Given that the ability to predict system-wide consequences is still somewhat limited, they describe several axes of variation for resources and consumers that will influence the responses of ecological systems to pulsed resources. In Chapter 3, With argues that most landscapes bear the imprint of past human land use (legacy effects) that in some cases date back centuries or even millennia, even after the landscape seemingly has been restored to its natural pre-settlement state. She explains that as a result, current species distributions may thus better reflect historical than contemporary landscape configurations, owing to the lagged response of species to landscape change. With illustrates these "ghosts of landscapes past" with several case studies. In Chapter 4, Grimm and his colleagues use individual-based models that incorporate adaptive behavior to understand animal response. They explain that the adaptive responses of individuals to short-term environmental conditions give rise to population- and community-level phenomena. They provide a rationale for the framework and provide case examples to illustrate the concepts. In Chapter 5, the last of section 1, Gunderson and his colleagues concentrate on the scaling axis of time, and describe cycles in temporal patterns in the Everglades ecosystem. They relate the temporal frequencies of ecosystem structuring processes to the interaction of animals with their environment, and describe how spatial and temporal turnover and variability in animal communities relate to variation in the availability of resources in time and space. They posit that discontinuous distributions of key structuring variables in time should be manifest as a few resonant frequencies in temporal processes and test their ideas with time series data of rainfall, evaporation, water-flow, air temperature, sea level, and fire history. In section 2, Statistics of Time, Gutzwiller and Riffell address in Chapter 6 the issue of measuring temporal variation in animal responses to landscape conditions. They suggest that several statistical modeling approaches are appropriate for explicitly incorporating time into analyses of animal-landscape relations, but landscape ecologists have not commonly used them. They explain that the analytical assessment of temporal variation may involve independent or dependent data. If independent data are used, interaction effects involving time and landscape metrics can be estimated using cross-product terms. With dependent or repeated measures data, Gutzwiller and Riffell explain that the analytical assessment of temporal variation may involve up to three dimensions. They provide a clearly explained approach for the analysis of larger scale temporal data. In Chapter 7, Cushman and McGarigal develop and demonstrate for the reader a flexible multivariate approach to analyze landscape pattern trajectories over time. They combine a habitat suitability model for marten, metrics from FRAGSTATS, and a multi-temporal principle components analysis to define a parsimonious suite of independent landscape gradients and to project changes in marten habitat as a series of trajectories in space. Section 3, Temporally Focused Case Studies, contains 7 chapters. In Chapter 8, Storch illustrates limitations of conventional habitat assessments caused by smaller-scale temporal variation in rainfall patterns that may lead to inappropriate management action, using case examples of Capercaillie Tetrao urogallus in the German Alps. The examples show that standard "snapshot" habitat assessments ignore temporal variation and may have major consequences for species-habitat relationships and population dynamics, and thus, for management and conservation planning. In Chapter 9, Mooij, Martin, Kitchens, and DeAngelis explore the viability of the Florida snail kite Rostrhamus sociabilis plumbeus population under different spatially and temporally explicit seasonal drought regimes in its wetland habitat. The Florida snail kite is an endangered raptor that occurs as an isolated population of about 2000 birds in the wetlands of southern and central Florida. To explore the interplay between the timing and spatial synchronization of water resource availability, Mooij and his colleagues used an individual-based snail kite simulation approach that modeled kite behavioral responses. Because of its weekly time resolution, the model discriminated relatively subtle temporal variations in hydro-logical patterns. Their results revealed the complexity of the effects of temporal variation in water levels on snail kite population dynamics. Specifically, they found that management decisions should not be based on annual mean water levels alone, but must consider intra-annual variability. In Chapter 10, Reynolds and Mitchell argue strongly that the spatiotemporal resolution of observations should match the level of the ecological process under study if reliable insights are to be gained. They present a concept of designing ecological studies that integrates three axes: temporal resolution of the study, spatial resolution of the study, and the resolution of the ecological process addressed. To buttress their arguments, Reynolds and Mitchell provide two examples from their long-term research on black bears
Ursus americanus. They show that the temporal scales at which different vital rates are manifested in a bear population may differ, and affects the way disturbances (e.g., clearcuts, roads) affect habitat quality. In Chapter 11, Felix, Linden, and Campa argue that land-cover databases can be used to understand wildlife-habitat relationships but do not identify vegetation structure, temporally explicit vegetation trends, successional dynamics, or vegetation types on distinctive soils that may have different wildlife values. They suggest that the use of ecological classification systems, where ecosystems are classified and mapped according to specific biotic and abiotic properties, can facilitate assessment of distributions and movements of wildlife populations based on spatial and temporal identification of resources necessary for survival. They use a habitat-type classification system, which is a specific type of ecological classification system, as a basis to predict vegetation development and successional change. They discuss three case studies fromMichi-gan to demonstrate how to build and apply models to assess temporal changes in forest wildlife habitat. One case study determined the potential of habitat types to provide white-tailed deer Odocoileus virginianus habitat, a second characterized how structure and composition of aspen Populus spp. changes throughout succession in different habitat types, and a third case used GIS to analyze differences in land use and land cover over the last century and model changes in the location and suitability of habitat for the threatened Canada lynx Lynx canadensis in the Upper Peninsula of Michigan. In Chapter 12, Lewis explains how the historically commonbutnow endangered Gouldianfinch Erythrura gouldiae of Australia has suffered dramatic reductions in population numbers during the last 40 years. Possible causative scenarios, including (a) increased commercial livestock grazing, (b) commercial trapping, and (c) parasite infections, have had limited success in explaining the continued decline in the number and size of Gouldian finch populations. Unlike other Australian finches, the Gouldian finch is solely granivorous and relies upon native grass species for survival. In this chapter, Lewis presents experimental evidence to show that different patterns of seed production are dependent upon fire periodicity and the intensity of burning, and that in breeding seasons following periods of reduced fire intensity and therefore higher seed production, there is about a 30% increase in reproductive success and increased survival of adult Gouldian finches. Lewis argues that understanding the temporal patterning and spatial distribution of resources across the landscape provides valuable perspectives on how to manage landscapes for declining species such as the Gouldian finch. In Chapter 13, Drever and Martin argue that in the mixed forests of interior British Columbia, Canada, temporal trends may have more dramatic effects than spatial patterns on species responses. Time and space interact and the drivers of temporal change differ spatially for short and long distant migrant species that respond to ecological conditions at a continental scale extent compared to resident species where temporal trends are driven by climate change and forest management conditions at a landscape or regional scale extent. The authors conducted a study that involved multi-annual responses of cavity nesters to an ongoing major outbreak of mountain pine beetle (Dendroctonus ponderosae) and other bark beetles and forest insects in British Columbia that resulted in large-scale increases in the availability of dead and dying trees. In addition to the annual variation in phenology, breeding density, and reproductive success, unexpected and dramatic directional temporal changes occurred. Drever and Martin were able to fit a linear trend model to 100 species observed during point counts, of which 21 showed a significant decline in abundance over the study period, 21 showed an increase in abundance, and 58 showed no trend. These concurrent declines and increases in abundance mean that community-level measures such as species richness and abundance within cavity-nesting guild did not change following the outbreak, indicating that community structure, per se, has remained stable during the large increase in resource availability. These results suggest that species' responses to the availability of resources may thus also depend on the current status of competitors, predators, and facilitators. In Chapter 14, MacLeod, Parish, and Robinson used an introduced bird species, the yellowhammer Emberiza citrinella L. in New Zealand as a model to test predictions based on the niche opportunities hypothesis. They tested the prediction that the success of yellowhammers in New Zealand can be explained by differences in temporal variation in availability of better quality food resources in its introduced range compared to its native range; specifically that (a) winter seed resources were more abundant; and (b) there was less temporal variation in resource availability during the breeding season in New Zealand. They found that Yellowhammer breeding territory densities were over three times higher in New Zealand (0.40 territories per ha) than in comparable British farmland (0.12 territories per ha), however, they also found that niche availability and quality, as indexed and measured by habitat availability and invertebrate densities, could not explain the higher density of yellowhammers in New Zealand.
Was this article helpful?