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• 1. [Article] Increased Taxonomic and Functional Similarity Does Not Increase the Trophic Similarity of Communities

  Aim: Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship ...

  Citation × Citation Citation Abstract Copy Title: Increased Taxonomic and Functional Similarity Does Not Increase the Trophic Similarity of Communities Author: Pool, Thomas K., Cucherousset, Julien, Boulêtreau, Stéphanie, Villéger, Sébastien, Strecker, Angela L., Grenouillet, Gaël Year: 2015 Aim: Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship remains limited. Community assembly theory predicts that niche partitioning will result in communities with a diverse array of functional traits, which in turn may facilitate a correspondingly diverse array of trophic interactions that define the trophic niche of those communities. The aim of our study is to test this prediction. Methods: We built a database composed of functional traits and stable isotope values (δ13C and δ15N) for 63 freshwater fish communities containing 109 species in 34 lentic and 29 lotic ecosystems. First, using linear mixed models (i.e. an alpha-diversity approach), we tested whether the taxonomic diversity of communities was positively associated with their functional diversity and if their functional diversity was positively associated with their trophic diversity. Second, we assessed the taxonomic, functional and trophic similarity of communities using multiple regression on distance matrices (MRM) and their respective ‘turnover’ and ‘nestedness-resultant’ components to test if the taxonomic similarity of communities was positively correlated with their functional similarity and if their functional similarity was positively associated with their trophic similarity (i.e. a beta-diversity approach). Results: We found that the functional diversity of communities increased as their taxonomic diversity increased. Similarly, the trophic diversity of communities increased as their functional diversity increased. The pairwise taxonomic and functional similarity of communities were also positively associated, but there was a weak relationship between the functional and trophic similarities of communities. Main conclusions: Our study demonstrates that communities with similar functional characteristics can have disparate food web structures, suggesting that additional site-specific factors influence community variation in trophic niche geometry. Determining the relative importance of functional characteristics and site-specific factors in shaping trophic interactions is crucial for a better understanding of how future species loss and species introductions will affect food web structure and ecosystem functioning. Title: Increased Taxonomic and Functional Similarity Does Not Increase the Trophic Similarity of Communities Author: Pool, Thomas K., Cucherousset, Julien, Boulêtreau, Stéphanie, Villéger, Sébastien, Strecker, Angela L., Grenouillet, Gaël Year: 2015 Aim: Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship remains limited. Community assembly theory predicts that niche partitioning will result in communities with a diverse array of functional traits, which in turn may facilitate a correspondingly diverse array of trophic interactions that define the trophic niche of those communities. The aim of our study is to test this prediction. Methods: We built a database composed of functional traits and stable isotope values (δ13C and δ15N) for 63 freshwater fish communities containing 109 species in 34 lentic and 29 lotic ecosystems. First, using linear mixed models (i.e. an alpha-diversity approach), we tested whether the taxonomic diversity of communities was positively associated with their functional diversity and if their functional diversity was positively associated with their trophic diversity. Second, we assessed the taxonomic, functional and trophic similarity of communities using multiple regression on distance matrices (MRM) and their respective ‘turnover’ and ‘nestedness-resultant’ components to test if the taxonomic similarity of communities was positively correlated with their functional similarity and if their functional similarity was positively associated with their trophic similarity (i.e. a beta-diversity approach). Results: We found that the functional diversity of communities increased as their taxonomic diversity increased. Similarly, the trophic diversity of communities increased as their functional diversity increased. The pairwise taxonomic and functional similarity of communities were also positively associated, but there was a weak relationship between the functional and trophic similarities of communities. Main conclusions: Our study demonstrates that communities with similar functional characteristics can have disparate food web structures, suggesting that additional site-specific factors influence community variation in trophic niche geometry. Determining the relative importance of functional characteristics and site-specific factors in shaping trophic interactions is crucial for a better understanding of how future species loss and species introductions will affect food web structure and ecosystem functioning. Close

• 2. [Article] Ecological Homogenization of Urban USA

  A visually apparent but scientifically untested outcome of land-use change is homogenization across urban areas, where neighborhoods in different parts of the country have similar patterns of roads, residential ...

  Citation × Citation Citation Abstract Copy Title: Ecological Homogenization of Urban USA Author: Groffman, Peter M., Cavender-Bares, Jeannine, Bettez, Neil D., Grove, J. Morgan, Hall, Sharon J., Heffernan, James B., Hobbie, Sarah E., Larson, Kelli L., Morse, Jennifer L., Neill, Christopher, Nelson, Kristen C., O'Neil-Dunne, Jarlath, Pataki, Diane E., Polsky, Colin, Chowdhury, Rinku Roy, Steele, Meredith K. Year: 2014 A visually apparent but scientifically untested outcome of land-use change is homogenization across urban areas, where neighborhoods in different parts of the country have similar patterns of roads, residential lots, commercial areas, and aquatic features. We hypothesize that this homogenization extends to ecological structure and also to ecosystem functions such as carbon dynamics and microclimate, with continental-scale implications. Further, we suggest that understanding urban homogenization will provide the basis for understanding the impacts of urban land-use change from local to continental scales. Here, we show how multi-scale, multi-disciplinary datasets from six metropolitan areas that cover the major climatic regions of the US (Phoenix, AZ; Miami, FL; Baltimore, MD; Boston, MA; Minneapolis–St Paul, MN; and Los Angeles, CA) can be used to determine how household and neighborhood characteristics correlate with land-management practices, land-cover composition, and landscape structure and ecosystem functions at local, regional, and continental scales. Title: Ecological Homogenization of Urban USA Author: Groffman, Peter M., Cavender-Bares, Jeannine, Bettez, Neil D., Grove, J. Morgan, Hall, Sharon J., Heffernan, James B., Hobbie, Sarah E., Larson, Kelli L., Morse, Jennifer L., Neill, Christopher, Nelson, Kristen C., O'Neil-Dunne, Jarlath, Pataki, Diane E., Polsky, Colin, Chowdhury, Rinku Roy, Steele, Meredith K. Year: 2014 A visually apparent but scientifically untested outcome of land-use change is homogenization across urban areas, where neighborhoods in different parts of the country have similar patterns of roads, residential lots, commercial areas, and aquatic features. We hypothesize that this homogenization extends to ecological structure and also to ecosystem functions such as carbon dynamics and microclimate, with continental-scale implications. Further, we suggest that understanding urban homogenization will provide the basis for understanding the impacts of urban land-use change from local to continental scales. Here, we show how multi-scale, multi-disciplinary datasets from six metropolitan areas that cover the major climatic regions of the US (Phoenix, AZ; Miami, FL; Baltimore, MD; Boston, MA; Minneapolis–St Paul, MN; and Los Angeles, CA) can be used to determine how household and neighborhood characteristics correlate with land-management practices, land-cover composition, and landscape structure and ecosystem functions at local, regional, and continental scales. Close