Spider and Beetle Communities across Urban Greenspaces in Cleveland, Ohio: Distributions, Patterns, and Processes
| Autor: | Delgado de la flor, Yvan A. |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Animals
Agriculture Behavioral Sciences Biology Biostatistics Ecology Entomology Environmental Science Forestry Molecular Biology Soil Sciences Urban Planning Urban Forestry Wildlife Conservation Wildlife Management vacant lots urban ecology beetles spiders Pardosa milvina shrinking cities DNA metabarcoding gut content analysis environmental filtering niche breadth niche overlap structural equation modeling functional diversity null model species traits |
| Druh dokumentu: | Text |
| Popis: | Urban areas are often considered adverse environments for wildlife communities given that the colonization and establishment of local species pools are disrupted by biotic and abiotic changes at different spatial scales such as the introduction of invasive species, periodic mowing, and changes in soil and air quality. Although the number of people residing in cities has increased in the last century, over 300 cities worldwide have shrunk due to prolonged economic decline and population loss, resulting in thousands of newly available greenspaces scattered throughout cities. Consequently, interest in urban greenspaces as sites for conservation has grown considerably, raising questions about the ability of these habitats to support wildlife. As novel ecosystems, urban areas represent a set of new challenges for local species pools, yet the mechanisms driving community assembly processes within cities is a major knowledge gap. My work focused on identifying species distributions, patterns, and processes leading to the successful establishment arthropods in cities. For this, I chose to work with beetle and spider assemblages as they are considered biological indicators of environmental changes at small and large spatial scales and are taxonomically and functionally diverse predatory groups.In Chapter 1, my objective was to determine how urban greenspaces management and design impacts Carabidae and Staphylinidae beetles using taxonomic and life-history trait approaches. I found that ecological and morphological traits were good indicators of how beetles were responding to greenspace management strategies. Most species were negatively associated with building structures, while undisturbed habitats supported more hygrophilous and brachypterous beetle populations.In Chapter 2, I investigated the importance of local and landscape characteristics on spider communities using taxonomic and functional diversity approaches. I found that Pardosa milvina (Lycosidae) was the most abundant spider in our system. Plant height favored larger species, while mowing frequency benefited small spiders, leading to lower than expected functional alpha and beta diversity of spider communities. I also found that patch isolation and impervious surface increased the functional dissimilarity of spider communities.In Chapter 3, I examined the dietary niche breadth and niche overlap of the generalist spider P. milvina using DNA gut-content analysis. I found that dietary niche breadth was not greater within urban pockets, and Diptera, Hemiptera, and Collembola were often preyed by this urban-adapted spider. I also found that P. milvina predation patterns were driven by foraging strategies, suggesting that taxonomic identify and nutritional content were more important than prey availability.In Chapter 4, my goal was to determine the habitat characteristics and landscape variables influencing spider functional groups directly and indirectly. Using structural equation modeling, I found that web spiders were negatively correlated with plant biomass, hunting spiders were positively associated with available prey breadth, and both spider functional groups were positively correlated with heavy-metal pollution in the soil.In summary, my work showed that urban greenspace management and design play important roles shaping beetle and spider communities within cities. I also highlighted the importance of using multi-trophic and molecular approaches coupled with multivariate methodologies to disentangle local food web interactions and elucidate the mechanisms shaping community assembly processes of urban species pools. Investments in managed greenspaces that require infrequent mowing (i.e. urban prairies) will enhance the populations of beneficial arthropods, such as spiders and beetles, and beautify local neighborhoods. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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