{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/104845"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/104845","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Incidence, mechanisms, and consequences of adaptive habitat selection by the dickcissel (Spiza americana)","abstract":"Most animals display preferences when faced with the choice of habitats in which to settle. A key question that arises from these behaviors is whether preferences represent adaptive habitat selection—do animals occupying preferred habitats incur fitness benefits? A prediction based on natural selection suggests that preferences should increase fitness, but this prediction is not always supported. Several factors may cause preference-fitness mismatches, including temporal variability of variables driving reproductive success, tradeoffs across spatial scales or among fitness components, and anthropogenic changes disrupting historic relationships between habitat preferences and habitat quality. This dissertation presents three studies I conducted on the habitat preferences and reproductive success of dickcissels (Spiza americana) in the Grand River Grasslands of southern Iowa. I first tested for signals of adaptive habitat selection, examining whether male and female birds’ preferences among territories and larger habitat patches improve their ability to attract mates, avoid parasitism by brown-headed cowbirds (Molothrus ater), and produce robust offspring. Dickcissels engaged in adaptive habitat selection in some respects—such as preferring territories associated with high offspring condition and patches where parasitism was infrequent—but there was strong variation across sexes, spatial scales, years, and reproductive components. Next, I examined whether dickcissels used vegetation cues to select high-quality habitats. I measured multiple vegetation features in territories and patches and compared these to dickcissel habitat preferences and fitness metrics. Although dickcissels preferred specific vegetation features (again, with variation across sexes and scales), and specific vegetation features were associated with fitness (again, with variation across reproductive metrics), I found limited evidence that vegetation mediated adaptive habitat selection. Finally, I further studied the impacts of vegetation on dickcissel reproduction by focusing on the relative impacts of human-altered habitat components (invasive plants and broad-scale land cover) on nest survival and parasitism. I found that an invasive grass common throughout the Midwest region (tall fescue, Schedonorus arundinaceus) reduced nest survival and increased parasitism, whereas increasing woodland cover in the landscape reduced parasitism. In these studies, I illuminated proximate and ultimate forces shaping the reproductive ecology of dickcissels. I demonstrated that habitat preferences—and thus the spatiotemporal dynamics of population distributions—benefit specific components of reproductive success at particular spatial scales, while benefits to other reproductive metrics are variable across time. These results show that because fitness results from a wide variety of ecological processes, accurate assessments of adaptive habitat selection require a complex perspective. In addition, I have contributed to our knowledge of how vegetation influences dickcissel settlement patterns, while showing that preferred vegetation components have little influence on fitness. Other mechanisms (e.g., site fidelity, conspecific attraction, food availability, predator abundance) may thus play a stronger role in facilitating adaptive habitat selection. At the same time, I found strong evidence that vegetation altered by human activity shapes dickcissel habitat quality, and my results suggest that controlling invasive tall fescue may improve dickcissel nest success.","abstract_html":"Most animals display preferences when faced with the choice of habitats in which to settle. A key question that arises from these behaviors is whether preferences represent adaptive habitat selection—do animals occupying preferred habitats incur fitness benefits? A prediction based on natural selection suggests that preferences should increase fitness, but this prediction is not always supported. Several factors may cause preference-fitness mismatches, including temporal variability of variables driving reproductive success, tradeoffs across spatial scales or among fitness components, and anthropogenic changes disrupting historic relationships between habitat preferences and habitat quality. This dissertation presents three studies I conducted on the habitat preferences and reproductive success of dickcissels (Spiza americana) in the Grand River Grasslands of southern Iowa. I first tested for signals of adaptive habitat selection, examining whether male and female birds’ preferences among territories and larger habitat patches improve their ability to attract mates, avoid parasitism by brown-headed cowbirds (Molothrus ater), and produce robust offspring. Dickcissels engaged in adaptive habitat selection in some respects—such as preferring territories associated with high offspring condition and patches where parasitism was infrequent—but there was strong variation across sexes, spatial scales, years, and reproductive components. Next, I examined whether dickcissels used vegetation cues to select high-quality habitats. I measured multiple vegetation features in territories and patches and compared these to dickcissel habitat preferences and fitness metrics. Although dickcissels preferred specific vegetation features (again, with variation across sexes and scales), and specific vegetation features were associated with fitness (again, with variation across reproductive metrics), I found limited evidence that vegetation mediated adaptive habitat selection. Finally, I further studied the impacts of vegetation on dickcissel reproduction by focusing on the relative impacts of human-altered habitat components (invasive plants and broad-scale land cover) on nest survival and parasitism. I found that an invasive grass common throughout the Midwest region (tall fescue, Schedonorus arundinaceus) reduced nest survival and increased parasitism, whereas increasing woodland cover in the landscape reduced parasitism. In these studies, I illuminated proximate and ultimate forces shaping the reproductive ecology of dickcissels. I demonstrated that habitat preferences—and thus the spatiotemporal dynamics of population distributions—benefit specific components of reproductive success at particular spatial scales, while benefits to other reproductive metrics are variable across time. These results show that because fitness results from a wide variety of ecological processes, accurate assessments of adaptive habitat selection require a complex perspective. In addition, I have contributed to our knowledge of how vegetation influences dickcissel settlement patterns, while showing that preferred vegetation components have little influence on fitness. Other mechanisms (e.g., site fidelity, conspecific attraction, food availability, predator abundance) may thus play a stronger role in facilitating adaptive habitat selection. At the same time, I found strong evidence that vegetation altered by human activity shapes dickcissel habitat quality, and my results suggest that controlling invasive tall fescue may improve dickcissel nest success.","abstract_has_math":false,"creators":["Nelson, Scott Brent"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Natural Res & Env Sciences","degree_department":null,"school":null,"contributors":["Miller, James R.","Schooley, Robert L.","Fraterrigo, Jennifer M.","Benson, Thomas J."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-08-23T19:55:40Z","date_published":"2019-08-23T19:55:40Z","updated_at":"2026-07-22T22:24:42Z","subjects":["Brown-headed cowbird","Dickcissel","Fitness","Grassland bird","Habitat preference","Habitat quality","Spatial scale","Spiza americana","Tall fescue","Vegetation"],"languages":["en"],"rights":["Copyright 2019 Scott Nelson"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/104845","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Miller, James R.","Schooley, Robert L.","Fraterrigo, Jennifer M.","Benson, Thomas J."]},{"key":"dc:creator","label":"Author","values":["Nelson, Scott Brent"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-08-23T19:55:40Z","2019-04-18","2019-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Natural Res & Env Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Brown-headed cowbird","Dickcissel","Fitness","Grassland bird","Habitat preference","Habitat quality","Spatial scale","Spiza americana","Tall fescue","Vegetation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2019 Scott Nelson"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/104845"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Most animals display preferences when faced with the choice of habitats in which to settle. A key question that arises from these behaviors is whether preferences represent adaptive habitat selection—do animals occupying preferred habitats incur fitness benefits? A prediction based on natural selection suggests that preferences should increase fitness, but this prediction is not always supported. Several factors may cause preference-fitness mismatches, including temporal variability of variables driving reproductive success, tradeoffs across spatial scales or among fitness components, and anthropogenic changes disrupting historic relationships between habitat preferences and habitat quality. This dissertation presents three studies I conducted on the habitat preferences and reproductive success of dickcissels (Spiza americana) in the Grand River Grasslands of southern Iowa. I first tested for signals of adaptive habitat selection, examining whether male and female birds’ preferences among territories and larger habitat patches improve their ability to attract mates, avoid parasitism by brown-headed cowbirds (Molothrus ater), and produce robust offspring. Dickcissels engaged in adaptive habitat selection in some respects—such as preferring territories associated with high offspring condition and patches where parasitism was infrequent—but there was strong variation across sexes, spatial scales, years, and reproductive components. Next, I examined whether dickcissels used vegetation cues to select high-quality habitats. I measured multiple vegetation features in territories and patches and compared these to dickcissel habitat preferences and fitness metrics. Although dickcissels preferred specific vegetation features (again, with variation across sexes and scales), and specific vegetation features were associated with fitness (again, with variation across reproductive metrics), I found limited evidence that vegetation mediated adaptive habitat selection. Finally, I further studied the impacts of vegetation on dickcissel reproduction by focusing on the relative impacts of human-altered habitat components (invasive plants and broad-scale land cover) on nest survival and parasitism. I found that an invasive grass common throughout the Midwest region (tall fescue, Schedonorus arundinaceus) reduced nest survival and increased parasitism, whereas increasing woodland cover in the landscape reduced parasitism. In these studies, I illuminated proximate and ultimate forces shaping the reproductive ecology of dickcissels. I demonstrated that habitat preferences—and thus the spatiotemporal dynamics of population distributions—benefit specific components of reproductive success at particular spatial scales, while benefits to other reproductive metrics are variable across time. These results show that because fitness results from a wide variety of ecological processes, accurate assessments of adaptive habitat selection require a complex perspective. In addition, I have contributed to our knowledge of how vegetation influences dickcissel settlement patterns, while showing that preferred vegetation components have little influence on fitness. Other mechanisms (e.g., site fidelity, conspecific attraction, food availability, predator abundance) may thus play a stronger role in facilitating adaptive habitat selection. At the same time, I found strong evidence that vegetation altered by human activity shapes dickcissel habitat quality, and my results suggest that controlling invasive tall fescue may improve dickcissel nest success.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-08-22 without embargo terms","The student, Scott Nelson, accepted the attached license on 2019-04-16 at 13:42.","The student, Scott Nelson, submitted this Dissertation for approval on 2019-04-16 at 18:25.","This Dissertation was approved for publication on 2019-04-18 at 13:10.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13677 on 2019-08-22 at 14:44:05","Made available in DSpace on 2019-08-23T19:55:40Z (GMT). No. of bitstreams: 5 NELSON-DISSERTATION-2019.pdf: 2336372 bytes, checksum: df8a33632e6252b02d19c598b8741fb4 (MD5) Scott B. 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A key question that arises from these behaviors is whether preferences represent adaptive habitat selection—do animals occupying preferred habitats incur fitness benefits? A prediction based on natural selection suggests that preferences should increase fitness, but this prediction is not always supported. Several factors may cause preference-fitness mismatches, including temporal variability of variables driving reproductive success, tradeoffs across spatial scales or among fitness components, and anthropogenic changes disrupting historic relationships between habitat preferences and habitat quality. This dissertation presents three studies I conducted on the habitat preferences and reproductive success of dickcissels (Spiza americana) in the Grand River Grasslands of southern Iowa. I first tested for signals of adaptive habitat selection, examining whether male and female birds’ preferences among territories and larger habitat patches improve their ability to attract mates, avoid parasitism by brown-headed cowbirds (Molothrus ater), and produce robust offspring. Dickcissels engaged in adaptive habitat selection in some respects—such as preferring territories associated with high offspring condition and patches where parasitism was infrequent—but there was strong variation across sexes, spatial scales, years, and reproductive components. Next, I examined whether dickcissels used vegetation cues to select high-quality habitats. I measured multiple vegetation features in territories and patches and compared these to dickcissel habitat preferences and fitness metrics. Although dickcissels preferred specific vegetation features (again, with variation across sexes and scales), and specific vegetation features were associated with fitness (again, with variation across reproductive metrics), I found limited evidence that vegetation mediated adaptive habitat selection. Finally, I further studied the impacts of vegetation on dickcissel reproduction by focusing on the relative impacts of human-altered habitat components (invasive plants and broad-scale land cover) on nest survival and parasitism. I found that an invasive grass common throughout the Midwest region (tall fescue, Schedonorus arundinaceus) reduced nest survival and increased parasitism, whereas increasing woodland cover in the landscape reduced parasitism. In these studies, I illuminated proximate and ultimate forces shaping the reproductive ecology of dickcissels. I demonstrated that habitat preferences—and thus the spatiotemporal dynamics of population distributions—benefit specific components of reproductive success at particular spatial scales, while benefits to other reproductive metrics are variable across time. These results show that because fitness results from a wide variety of ecological processes, accurate assessments of adaptive habitat selection require a complex perspective. In addition, I have contributed to our knowledge of how vegetation influences dickcissel settlement patterns, while showing that preferred vegetation components have little influence on fitness. Other mechanisms (e.g., site fidelity, conspecific attraction, food availability, predator abundance) may thus play a stronger role in facilitating adaptive habitat selection. At the same time, I found strong evidence that vegetation altered by human activity shapes dickcissel habitat quality, and my results suggest that controlling invasive tall fescue may improve dickcissel nest success.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-08-22 without embargo terms","The student, Scott Nelson, accepted the attached license on 2019-04-16 at 13:42.","The student, Scott Nelson, submitted this Dissertation for approval on 2019-04-16 at 18:25.","This Dissertation was approved for publication on 2019-04-18 at 13:10.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13677 on 2019-08-22 at 14:44:05","Made available in DSpace on 2019-08-23T19:55:40Z (GMT). No. of bitstreams: 5 NELSON-DISSERTATION-2019.pdf: 2336372 bytes, checksum: df8a33632e6252b02d19c598b8741fb4 (MD5) Scott B. 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