Competition and predation as processes affecting community patterns of geese.

• Main Authors: Gawlik, Dale Edward., Texas A&M University.
• Format: Text
• Language: English
• Subjects: Biology; Ecology.; Zoology.; Agriculture; Forestry and Wildlife.; Canada; Branta canadensis
• Online Access: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9506635; http://ezproxy.fau.edu; http://digitool.fcla.edu:80/R/?func=dbin-jump-full&object_id=40774

I investigated patterns of behavior, association, and abundance for geese at three organizational scales (i.e., population, flock, and individual) to determine the relative effects of interspecific competition, intraspecific competition, and predation. I examined patterns of population density, habitat use, niche breadth, niche overlap, flock structure, foraging behavior, and absolute energetic expenditure for Snow Geese (Chen caerulescens), Greater White-fronted Geese (Anser albifrons), and Canada Geese (Branta canadensis). This study was conducted during November 1991 to February 1992 and October 1992 to February 1993, in southeastern Texas. Snow Geese overlapped considerably with white-fronted and Canada geese along resource axes of time, habitat, and food, and used a broader range of these resources than either of the latter two species. White-fronted and Canada geese overlapped less on time and habitat use and more on diet. These two species also showed more restrictive patterns of temporal abundance and habitat use than did Snow Geese. Collectively, these patterns are consistent with those of a community structured to minimize competition for food by exhibiting niche complementarity. Regression analyses indicated food (waste rice grain) most strongly influenced population abundance of white-fronted geese, whereas snow and Canada geese were affected by hunting pressure and food (green vegetation and waste rice grains) indirectly through interactions. At the flock level, all three species exhibited patterns strongly indicative of a response to predation, with lesser effects from food and heterospecifics. At the individual level, foraging behaviors were primarily affected by food type and abundance, with lesser effects from predation risk. The close link between Greater White-fronted Geese and waste-rice grain suggests that current declines in rice agriculture and the subsequent conversion of rice fields to pastureland will likely impact populations of white-fronted geese more severely than those of either snow or Canada geese. Thesis (Ph.D.)--Texas A&M University, 1994. I investigated patterns of behavior, association, and abundance for geese at three organizational scales (i.e., population, flock, and individual) to determine the relative effects of interspecific competition, intraspecific competition, and predation. I examined patterns of population density, habitat use, niche breadth, niche overlap, flock structure, foraging behavior, and absolute energetic expenditure for Snow Geese (Chen caerulescens), Greater White-fronted Geese (Anser albifrons), and Canada Geese (Branta canadensis). This study was conducted during November 1991 to February 1992 and October 1992 to February 1993, in southeastern Texas. Snow Geese overlapped considerably with white-fronted and Canada geese along resource axes of time, habitat, and food, and used a broader range of these resources than either of the latter two species. White-fronted and Canada geese overlapped less on time and habitat use and more on diet. These two species also showed more restrictive patterns of temporal abundance and habitat use than did Snow Geese. Collectively, these patterns are consistent with those of a community structured to minimize competition for food by exhibiting niche complementarity. Regression analyses indicated food (waste rice grain) most strongly influenced population abundance of white-fronted geese, whereas snow and Canada geese were affected by hunting pressure and food (green vegetation and waste rice grains) indirectly through interactions. At the flock level, all three species exhibited patterns strongly indicative of a response to predation, with lesser effects from food and heterospecifics. At the individual level, foraging behaviors were primarily affected by food type and abundance, with lesser effects from predation risk. The close link between Greater White-fronted Geese and waste-rice grain suggests that current declines in rice agriculture and the subsequent conversion of rice fields to pastureland will likely impact populations of white-fronted geese more severely than those of either snow or Canada geese. School code: 0803. hdl