32 research outputs found
Effects of branching spatial structure and life history on the asymptotic growth rate of a population
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Theoretical Ecology 3 (2010): 137-152, doi:10.1007/s12080-009-0058-0.The dendritic structure of a river network creates directional dispersal and a hierarchical
arrangement of habitats. These two features have important consequences for the
ecological dynamics of species living within the network.We apply matrix population models to a stage-structured population in a network of habitat patches connected in a dendritic
arrangement. By considering a range of life histories and dispersal patterns, both constant
in time and seasonal, we illustrate how spatial structure, directional dispersal, survival, and
reproduction interact to determine population growth rate and distribution. We investigate
the sensitivity of the asymptotic growth rate to the demographic parameters of the model,
the system size, and the connections between the patches. Although some general patterns
emerge, we find that a species’ mode of reproduction and dispersal are quite important in its
response to changes in its life history parameters or in the spatial structure. The framework
we use here can be customized to incorporate a wide range of demographic and dispersal
scenarios.Funding for this work came from the James S. McDonnell Foundation (EEG, HJL, WFF). MGN was supported by grants from the National Science Foundation (CMG-0530830, OCE-0326734, ATM-0428122)
Climate change effects on stream and river temperatures across the northwest U.S. from 1980–2009 and implications for salmonid fishes
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Restoring fire-prone Inland Pacific landscapes: seven core principles
© 2015 The Author(s) Context: More than a century of forest and fire management of Inland Pacific landscapes has transformed their successional and disturbance dynamics. Regional connectivity of many terrestrial and aquatic habitats is fragmented, flows of some ecological and physical processes have been altered in space and time, and the frequency, size and intensity of many disturbances that configure these habitats have been altered. Current efforts to address these impacts yield a small footprint in comparison to wildfires and insect outbreaks. Moreover, many current projects emphasize thinning and fuels reduction within individual forest stands, while overlooking large-scale habitat connectivity and disturbance flow issues. Methods: We provide a framework for landscape restoration, offering seven principles. We discuss their implication for management, and illustrate their application with examples. Results: Historical forests were spatially heterogeneous at multiple scales. Heterogeneity was the result of variability and interactions among native ecological patterns and processes, including successional and disturbance processes regulated by climatic and topographic drivers. Native flora and fauna were adapted to these conditions, which conferred a measure of resilience to variability in climate and recurrent contagious disturbances. Conclusions: To restore key characteristics of this resilience to current landscapes, planning and management are needed at ecoregion, local landscape, successional patch, and tree neighborhood scales. Restoration that works effectively across ownerships and allocations will require active thinking about landscapes as socio-ecological systems that provide services to people within the finite capacities of ecosystems. We focus attention on landscape-level prescriptions as foundational to restoration planning and execution
Evidence of Climate-Induced Range Contractions in Bull Trout Salvelinus confluentus in a Rocky Mountain Watershed, U.S.A
Initial mortality of radio-tagged Atlantic salmon (Salmo salar L.) smolts following release downstream of a hydropower station
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