Determining habitat quality for wildlife populations requires relating a species’habitat to its s... more Determining habitat quality for wildlife populations requires relating a species’habitat to its survival and reproduction. Within a season, species occurrence and density can be disconnected from measures of habitat quality when resources are highly seasonal, unpredictable over time, and patchy. Here we establish an explicit link among dynamic selection of changing resources, spatio-temporal species distributions, and fitness for predictive abundance and occurrence models that are used for short-term water management and long-term restoration planning. We used the wading bird distribution and evaluation models (WADEM) that estimate (1) daily changes in selection across resource gradients, (2) landscape abundance of flocks and individuals, (3) conspecific foraging aggregation, and (4) resource unit occurrence (at fixed 400 m cells) to quantify habitat quality and its consequences on reproduction for wetland indicator species. We linked maximum annual numbers of nests detected across the study area and nesting success of Great Egrets (Ardea alba), White Ibises (Eudocimus albus), and Wood Storks (Mycteria americana) over a 20-year period to estimated daily dynamics of food resources produced by WADEM over a 7490 km2 area. For all species, increases in predicted species abundance in March and high abundance in April were strongly linked to breeding responses.Great Egret nesting effort and success were higher when birds also showed greater conspecific foraging aggregation. Synthesis and applications: This study provides the first empirical evidence that dynamic habitat selection processes and distributions of wading birds over environmental gradients are linked with reproductive measures over periods of decades. Further, predictor variables at a variety of temporal (daily-multiannual) resolutions and spatial (400 m to regional) scales effectively explained variation in ecological processes that change habitat quality. The process used here allows managers to develop short- and long-term conservation strategies that (1) consider flexible behavioral patterns and (2) are robust to environmental variation over time.
Background/Question/Methods Wading birds are important indicator species for wetland ecosystems, ... more Background/Question/Methods Wading birds are important indicator species for wetland ecosystems, integrating productivity across trophic levels and over a large landscape scale. However, understanding and predicting wading bird responses to wetland restoration are hindered by their changing preference of hydrological processes depending on the production and concentration of prey. In the Everglades, populations of species that are visual foragers and tolerate relatively deep water (i.e., Great Egret; exploiter) have disproportionally increased when compared with populations of tactile foragers that require a higher prey density (i.e., White Ibis & Wood Stork; searchers). Identifying trade-offs among species between components of prey availability will help predict how communities respond to restoration. Locations of foraging Great Egrets, White Ibises, and Wood Storks were obtained from Systematic Reconnaissance Flight daily distribution data from 2000-2009. Temporal models grouped ...
The physiological condition of juvenile birds can be influenced by multiple ecological stressors,... more The physiological condition of juvenile birds can be influenced by multiple ecological stressors, and few studies have concurrently considered the effects of environmental contaminants in combination with ecological attributes that can influence foraging conditions and prey availability. Using three temporally distinct indices of physiological condition, we compared the physiological response of nestling great egrets (Ardea alba) and white ibises (Eudocimus albus) to changing prey availability, hydrology (water depth, recession rate), and mercury exposure in the Florida Everglades. We found that the physiological response of chicks varied between species and among environmental variables. Chick body condition (short-term index) and fecal corticosterone levels (medium-term) were influenced by wetland water depth, prey availability, region, and age, but not by mercury contamination. However, mercury exposure did influence heat shock protein 70 (HSP70) in egret chicks, indicating a lon...
Determining habitat quality for wildlife populations requires relating a species’habitat to its s... more Determining habitat quality for wildlife populations requires relating a species’habitat to its survival and reproduction. Within a season, species occurrence and density can be disconnected from measures of habitat quality when resources are highly seasonal, unpredictable over time, and patchy. Here we establish an explicit link among dynamic selection of changing resources, spatio-temporal species distributions, and fitness for predictive abundance and occurrence models that are used for short-term water management and long-term restoration planning. We used the wading bird distribution and evaluation models (WADEM) that estimate (1) daily changes in selection across resource gradients, (2) landscape abundance of flocks and individuals, (3) conspecific foraging aggregation, and (4) resource unit occurrence (at fixed 400 m cells) to quantify habitat quality and its consequences on reproduction for wetland indicator species. We linked maximum annual numbers of nests detected across the study area and nesting success of Great Egrets (Ardea alba), White Ibises (Eudocimus albus), and Wood Storks (Mycteria americana) over a 20-year period to estimated daily dynamics of food resources produced by WADEM over a 7490 km2 area. For all species, increases in predicted species abundance in March and high abundance in April were strongly linked to breeding responses.Great Egret nesting effort and success were higher when birds also showed greater conspecific foraging aggregation. Synthesis and applications: This study provides the first empirical evidence that dynamic habitat selection processes and distributions of wading birds over environmental gradients are linked with reproductive measures over periods of decades. Further, predictor variables at a variety of temporal (daily-multiannual) resolutions and spatial (400 m to regional) scales effectively explained variation in ecological processes that change habitat quality. The process used here allows managers to develop short- and long-term conservation strategies that (1) consider flexible behavioral patterns and (2) are robust to environmental variation over time.
Background/Question/Methods Wading birds are important indicator species for wetland ecosystems, ... more Background/Question/Methods Wading birds are important indicator species for wetland ecosystems, integrating productivity across trophic levels and over a large landscape scale. However, understanding and predicting wading bird responses to wetland restoration are hindered by their changing preference of hydrological processes depending on the production and concentration of prey. In the Everglades, populations of species that are visual foragers and tolerate relatively deep water (i.e., Great Egret; exploiter) have disproportionally increased when compared with populations of tactile foragers that require a higher prey density (i.e., White Ibis & Wood Stork; searchers). Identifying trade-offs among species between components of prey availability will help predict how communities respond to restoration. Locations of foraging Great Egrets, White Ibises, and Wood Storks were obtained from Systematic Reconnaissance Flight daily distribution data from 2000-2009. Temporal models grouped ...
The physiological condition of juvenile birds can be influenced by multiple ecological stressors,... more The physiological condition of juvenile birds can be influenced by multiple ecological stressors, and few studies have concurrently considered the effects of environmental contaminants in combination with ecological attributes that can influence foraging conditions and prey availability. Using three temporally distinct indices of physiological condition, we compared the physiological response of nestling great egrets (Ardea alba) and white ibises (Eudocimus albus) to changing prey availability, hydrology (water depth, recession rate), and mercury exposure in the Florida Everglades. We found that the physiological response of chicks varied between species and among environmental variables. Chick body condition (short-term index) and fecal corticosterone levels (medium-term) were influenced by wetland water depth, prey availability, region, and age, but not by mercury contamination. However, mercury exposure did influence heat shock protein 70 (HSP70) in egret chicks, indicating a lon...
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