... USA KENNETH H. POLLOCK, Institute of Statistics, North Carolina State University, Box 8203, R... more ... USA KENNETH H. POLLOCK, Institute of Statistics, North Carolina State University, Box 8203, Raleigh, NC 27695, USA DANA THOMAS, Department of ... 1989a,b) and a modified Mayfield procedure (Mayfield 1961, 1975; Johnson 1979) can be used under this general modeling ...
We measured forage intake, digestibility, and retention time for 11 free-ranging, human-imprinted... more We measured forage intake, digestibility, and retention time for 11 free-ranging, human-imprinted lesser snow geese (Chen caerulescens caerulescens) as they consumed underground stembases of tall cotton-grass (Eriophorum angustifolium) on an arctic staging area in northeastern Alaska. Geese fed in small patches ( \(\bar x\) =21.5 m2) of forage that made up ≤3% of the study area and consisted of high-quality “aquatic graminoid” and intermediate-quality “wet sedge” vegetation types. Dominant geese spent more time feeding in aquatic graminoid areas (r=0.61), but less total time feeding and more time resting than subdominant geese. Subdominant geese were displaced to areas of wet sedge where cotton-grass was a smaller proportion of underground biomass. Geese metabolized an average of 48% of the organic matter in stembases and there was a positive correlation between dominance and organic matter metabolizability (r=0.61). Total mean retention time of forage was 1.37 h and dry matter intake was 14.3 g/h. Snow geese that stage on the coastal plain of the Beaufort Sea likely use an extensive area because they consume a large mass of forage and exploit habitats that are patchily distributed and make up a small percentage of the landscape. Individual variation in nutrient absorption may result from agonistic interactions in an environment where resources are heterogeneously distributed.
... requirement in small, compared to large, geese (Brody 1945), but also is associated with the ... more ... requirement in small, compared to large, geese (Brody 1945), but also is associated with the re-duced ability of small geese to physically con-sume foods eaten by larger geese. ... 1989), Sage Grouse (Centrocer-cus urophasianus) (Remington and Braun 1985, Welch et al. ...
ABSTRACT Animals select habitat to satisfy life-history requirements, yet few habitat-selection s... more ABSTRACT Animals select habitat to satisfy life-history requirements, yet few habitat-selection studies consider multiple factors, especially food. Because resources vary in abundance and quality across different spatial scales or habitat types, selected habitat features may also vary, making habitat selection incongruent. Using an information-theoretical approach, we assessed whether Phainopeplas (Phainopepla nitens) select breeding habitat for food abundance or vegetation structure at nest-tree and nest-patch scales in two woodland types, acacia and mesquite, in the Mojave Desert. Habitat selection at the tree and patch scales was congruent: models containing both food (mistletoe) and structure variables had stronger support than models with only food or structure variables. In both woodland types, nest trees were larger and had more food, and in nest patches food abundance, tree density, tree height, and cover were greater than in non-nest patches. However, nests in acacia were higher than those in mesquite, acacia nest trees were smaller and had more food but less cover, and acacia nest patches had lower tree density and more food. These differences between woodland types apparently led to incongruence in nest-site selection: the difference between height of nest and non-nest trees was greater in shorter acacia than in mesquite woodlands, and the difference in food abundance between nest and non-nest sites was greater in food-poor mesquite woodlands. Contrary to assertions that vegetation structure drives nest-site selection, Phainopeplas’ nest-site selection reflects both food abundance and vegetation structure at all spatial scales, underscoring the importance of multiple factors, scales, and habitats to habitat-selection studies. Los animales seleccionan el hábitat para satisfacer los requerimientos de sus historias de vida, pero pocos estudios de selección de hábitat consideran múltiples factores, especialmente relacionados al alimento. Debido a que los recursos varían en abundancia y calidad a través de diferentes escalas espaciales o tipos de hábitat, los rasgos seleccionados del hábitat también pueden variar, haciendo que la selección del hábitat sea incongruente. Usando un enfoque basado en la teoría de la información, evaluamos si Phainopepla nitens selecciona los hábitats de anidación por la abundancia de alimentos o por la estructura de la vegetación a las escalas del árbol donde se ubica el nido y del parche donde se ubica el nido en dos tipos de bosque, acacia y mesquite, en el desierto de Mojave. La selección de hábitat a las escalas de árbol y de parche fue congruente: los modelos que contenían tanto variables de alimento (muérdago) como estructurales tuvieron un mayor apoyo que los modelos con sólo variables de alimento o variables estructurales. En ambos tipos de bosque, los árboles con nidos fueron mayores y tuvieron una mayor cantidad de alimento, y en los parches con nidos la abundancia de alimentos, la densidad de árboles, la altura de los árboles y la cobertura fueron mayores que en los árboles y parches sin nidos. Sin embargo, los nidos en acacia estuvieron más altos que en mesquite, los árboles de acacia con nidos fueron más pequeños y tuvieron mayor cantidad de alimento pero menos cobertura, y los parches de acacia con nidos tuvieron menor densidad de árboles y mayor cantidad de alimento. Estas diferencias entre los tipos de bosque llevan aparentemente a una incongruencia en la selección de los sitios para los nidos: la diferencia entre la altura de los árboles con nido y sin nido fue mayor en los bosques de acacia, que son de menor altura que los bosques de mesquite, y la diferencia en la abundancia de alimento entre sitios con y sin nidos fue mayor en los bosques de mesquite, que son más pobres en alimento. Contrariamente a las aseveraciones de que la estructura de la vegetación condiciona la selección de los sitios de anidación, la selección de los sitios de anidación por P. nitens refleja tanto la abundancia de alimento como la estructura de la vegetación a todas las escalas espaciales, poniendo de manifiesto la importancia de considerar múltiples factores, escalas y ambientes en los estudios de selección de hábitat.
... black brant with multi-state modeling and geographic information systems MARK S. LINDBERG, JA... more ... black brant with multi-state modeling and geographic information systems MARK S. LINDBERG, JAMES S. SEDINGER & ERIC A. REXSTAD, Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, USA ... Page 2. 726 MS Lindberg et al. ...
... Mark S. Lindberg 1, 4 , James S. Sedinger 1 , Dirk V. Derksen 2 , and Robert F. Rockwell 3 ..... more ... Mark S. Lindberg 1, 4 , James S. Sedinger 1 , Dirk V. Derksen 2 , and Robert F. Rockwell 3 ... Ecology and management of breeding waterfowl. ... 1993. Capturerecapture studies for multiple strata including non-Markovian transitions. Biometrics 49:11731187. Burnham, KP 1993. ...
Page 1. Ecology, 76(8), 1995, pp. 2404-2414 ? 1995 by the Ecological Society of AmericaENVIRONMEN... more Page 1. Ecology, 76(8), 1995, pp. 2404-2414 ? 1995 by the Ecological Society of AmericaENVIRONMENTAL INFLUENCE ON LIFE-HISTORY TRAITS: GROWTH, SURVIVAL, AND FECUNDITY IN BLACK BRANT (BRANTA BERNICLA)1 ...
... USA KENNETH H. POLLOCK, Institute of Statistics, North Carolina State University, Box 8203, R... more ... USA KENNETH H. POLLOCK, Institute of Statistics, North Carolina State University, Box 8203, Raleigh, NC 27695, USA DANA THOMAS, Department of ... 1989a,b) and a modified Mayfield procedure (Mayfield 1961, 1975; Johnson 1979) can be used under this general modeling ...
We measured forage intake, digestibility, and retention time for 11 free-ranging, human-imprinted... more We measured forage intake, digestibility, and retention time for 11 free-ranging, human-imprinted lesser snow geese (Chen caerulescens caerulescens) as they consumed underground stembases of tall cotton-grass (Eriophorum angustifolium) on an arctic staging area in northeastern Alaska. Geese fed in small patches ( \(\bar x\) =21.5 m2) of forage that made up ≤3% of the study area and consisted of high-quality “aquatic graminoid” and intermediate-quality “wet sedge” vegetation types. Dominant geese spent more time feeding in aquatic graminoid areas (r=0.61), but less total time feeding and more time resting than subdominant geese. Subdominant geese were displaced to areas of wet sedge where cotton-grass was a smaller proportion of underground biomass. Geese metabolized an average of 48% of the organic matter in stembases and there was a positive correlation between dominance and organic matter metabolizability (r=0.61). Total mean retention time of forage was 1.37 h and dry matter intake was 14.3 g/h. Snow geese that stage on the coastal plain of the Beaufort Sea likely use an extensive area because they consume a large mass of forage and exploit habitats that are patchily distributed and make up a small percentage of the landscape. Individual variation in nutrient absorption may result from agonistic interactions in an environment where resources are heterogeneously distributed.
... requirement in small, compared to large, geese (Brody 1945), but also is associated with the ... more ... requirement in small, compared to large, geese (Brody 1945), but also is associated with the re-duced ability of small geese to physically con-sume foods eaten by larger geese. ... 1989), Sage Grouse (Centrocer-cus urophasianus) (Remington and Braun 1985, Welch et al. ...
ABSTRACT Animals select habitat to satisfy life-history requirements, yet few habitat-selection s... more ABSTRACT Animals select habitat to satisfy life-history requirements, yet few habitat-selection studies consider multiple factors, especially food. Because resources vary in abundance and quality across different spatial scales or habitat types, selected habitat features may also vary, making habitat selection incongruent. Using an information-theoretical approach, we assessed whether Phainopeplas (Phainopepla nitens) select breeding habitat for food abundance or vegetation structure at nest-tree and nest-patch scales in two woodland types, acacia and mesquite, in the Mojave Desert. Habitat selection at the tree and patch scales was congruent: models containing both food (mistletoe) and structure variables had stronger support than models with only food or structure variables. In both woodland types, nest trees were larger and had more food, and in nest patches food abundance, tree density, tree height, and cover were greater than in non-nest patches. However, nests in acacia were higher than those in mesquite, acacia nest trees were smaller and had more food but less cover, and acacia nest patches had lower tree density and more food. These differences between woodland types apparently led to incongruence in nest-site selection: the difference between height of nest and non-nest trees was greater in shorter acacia than in mesquite woodlands, and the difference in food abundance between nest and non-nest sites was greater in food-poor mesquite woodlands. Contrary to assertions that vegetation structure drives nest-site selection, Phainopeplas’ nest-site selection reflects both food abundance and vegetation structure at all spatial scales, underscoring the importance of multiple factors, scales, and habitats to habitat-selection studies. Los animales seleccionan el hábitat para satisfacer los requerimientos de sus historias de vida, pero pocos estudios de selección de hábitat consideran múltiples factores, especialmente relacionados al alimento. Debido a que los recursos varían en abundancia y calidad a través de diferentes escalas espaciales o tipos de hábitat, los rasgos seleccionados del hábitat también pueden variar, haciendo que la selección del hábitat sea incongruente. Usando un enfoque basado en la teoría de la información, evaluamos si Phainopepla nitens selecciona los hábitats de anidación por la abundancia de alimentos o por la estructura de la vegetación a las escalas del árbol donde se ubica el nido y del parche donde se ubica el nido en dos tipos de bosque, acacia y mesquite, en el desierto de Mojave. La selección de hábitat a las escalas de árbol y de parche fue congruente: los modelos que contenían tanto variables de alimento (muérdago) como estructurales tuvieron un mayor apoyo que los modelos con sólo variables de alimento o variables estructurales. En ambos tipos de bosque, los árboles con nidos fueron mayores y tuvieron una mayor cantidad de alimento, y en los parches con nidos la abundancia de alimentos, la densidad de árboles, la altura de los árboles y la cobertura fueron mayores que en los árboles y parches sin nidos. Sin embargo, los nidos en acacia estuvieron más altos que en mesquite, los árboles de acacia con nidos fueron más pequeños y tuvieron mayor cantidad de alimento pero menos cobertura, y los parches de acacia con nidos tuvieron menor densidad de árboles y mayor cantidad de alimento. Estas diferencias entre los tipos de bosque llevan aparentemente a una incongruencia en la selección de los sitios para los nidos: la diferencia entre la altura de los árboles con nido y sin nido fue mayor en los bosques de acacia, que son de menor altura que los bosques de mesquite, y la diferencia en la abundancia de alimento entre sitios con y sin nidos fue mayor en los bosques de mesquite, que son más pobres en alimento. Contrariamente a las aseveraciones de que la estructura de la vegetación condiciona la selección de los sitios de anidación, la selección de los sitios de anidación por P. nitens refleja tanto la abundancia de alimento como la estructura de la vegetación a todas las escalas espaciales, poniendo de manifiesto la importancia de considerar múltiples factores, escalas y ambientes en los estudios de selección de hábitat.
... black brant with multi-state modeling and geographic information systems MARK S. LINDBERG, JA... more ... black brant with multi-state modeling and geographic information systems MARK S. LINDBERG, JAMES S. SEDINGER & ERIC A. REXSTAD, Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, USA ... Page 2. 726 MS Lindberg et al. ...
... Mark S. Lindberg 1, 4 , James S. Sedinger 1 , Dirk V. Derksen 2 , and Robert F. Rockwell 3 ..... more ... Mark S. Lindberg 1, 4 , James S. Sedinger 1 , Dirk V. Derksen 2 , and Robert F. Rockwell 3 ... Ecology and management of breeding waterfowl. ... 1993. Capturerecapture studies for multiple strata including non-Markovian transitions. Biometrics 49:11731187. Burnham, KP 1993. ...
Page 1. Ecology, 76(8), 1995, pp. 2404-2414 ? 1995 by the Ecological Society of AmericaENVIRONMEN... more Page 1. Ecology, 76(8), 1995, pp. 2404-2414 ? 1995 by the Ecological Society of AmericaENVIRONMENTAL INFLUENCE ON LIFE-HISTORY TRAITS: GROWTH, SURVIVAL, AND FECUNDITY IN BLACK BRANT (BRANTA BERNICLA)1 ...
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