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Variability In Population Abundance Is Associated With Thresholds Between Scaling Regimes, Donald Wardwell, Craig R. Allen
Variability In Population Abundance Is Associated With Thresholds Between Scaling Regimes, Donald Wardwell, Craig R. Allen
Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications
Discontinuous structure in landscapes may result in discontinuous, aggregated species bodymass patterns, reflecting the scales of structure available to animal communities within a landscape. The edges of these body-mass aggregations reflect transitions between available scales of landscape structure. Such transitions, or scale breaks, are theoretically associated with increased biological variability. We hypothesized that variability in population abundance is greater in animal species near the edge of bodymass aggregations than it is in species that are situated in the interior of body-mass aggregations. We tested this hypothesis by examining both temporal and spatial variability in the abundance of species in the …
A Test Of The Cross-Scale Resilience Model: Functional Richness In Mediterranean-Climate Ecosystems, Donald A. Wardwell, Craig R. Allen, Garry D. Peterson, Andrew J. Tyre
A Test Of The Cross-Scale Resilience Model: Functional Richness In Mediterranean-Climate Ecosystems, Donald A. Wardwell, Craig R. Allen, Garry D. Peterson, Andrew J. Tyre
Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications
Ecological resilience has been proposed to be generated, in part, in the discontinuous structure of complex systems. Environmental discontinuities are reflected in discontinuous, aggregated animal body mass distributions. Diversity of functional groups within body mass aggregations (scales) and redundancy of functional groups across body mass aggregations (scales) has been proposed to increase resilience. We evaluate that proposition by analyzing mammalian and avian communities of Mediterranean-climate ecosystems. We first determined that body mass distributions for each animal community were discontinuous. We then calculated the variance in richness of function across aggregations in each community, and compared observed values with distributions created …
Effects Of Red Imported Fire Ants On Northern Bobwhite Chicks, William M. Giuliano, Craig R. Allen, R. Scott Lutz, Stephen Demarais
Effects Of Red Imported Fire Ants On Northern Bobwhite Chicks, William M. Giuliano, Craig R. Allen, R. Scott Lutz, Stephen Demarais
Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications
Populations of red imported fire ants (RIFA; Solenopsis invtcta) have spread rapidly throughout the southeastern United States. RIFA, directly or indirectly, negatively affect many wildlife species, and northern bobwhite (Colinus virginianus) appear to be particularly susceptible. We examined the effect of exposure to different numbers of RIFA for 15 and 60 seconds on body mass and survival of captive northern bobwhite chicks. Compared to unexposed birds, survival of chicks was reduced with exposure to as few as 50 RIFA for 60 seconds, or 200 RIFA for 15 seconds, and body mass was lower in chicks exposed to …