2026-09-21T14:19:20Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/116059 2023-07-11 col_2142_5131 col_2142_14737 com_2142_5130 com_2142_690 com_2142_397

Molano-Flores, Brenda Zaya, David N Matthews, Jeffrey Benson, Thomas J Spyreas, Greg 2022-08 application/pdf en text Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-08-01 The student, Eric Janssen, accepted the attached license on 2022-07-07 at 12:17. The student, Eric Janssen, submitted this Thesis for approval on 2022-07-07 at 12:27. This Thesis was approved for publication on 2022-07-10 at 10:36. DSpace SAF Submission Ingestion Package generated from Vireo submission #18167 on 2022-11-15 at 19:17:09 Assessing colonization and extirpation trends of Illinois understory herbaceous plants using robust-design occupancy models Janssen, Eric Daniel 2022-07-10 robust-design occupancy models colonization extirpation forests Illinois plants Midwestern temperate forests are often small and isolated because of human disturbance. Plant species present in these forests are vulnerable to extirpation, with many landscape, site, and species characteristics influencing a species’ ability to persist in this hostile landscape. I used robust-design occupancy models to assess the role these three factors have in the occupancy, colonization, and extirpation probabilities of Illinois forest plants. Occupancy models create unbiased estimates for these probabilities by incorporating detection probability in the estimates, which has historically been overlooked in plant research. Species presences were gathered from multiple surveys of 124 sites (84 uplands, 40 floodplains) across Illinois from 1998-2017. The occupancy models created estimates for over 90% of the 426 unique species studied. Occupancy and colonization estimates were higher compared to naïve estimates, while extirpation estimates were lower. Landscape-level factors (e.g. surrounding forest and agriculture cover) influenced occupancy, colonization, and extirpation probabilities for the most species. At the site-level, species richness and mean coefficient of conservatism (mean C) influenced these parameters for the most species. For species-level characteristics, coefficient of conservatism, wetland plant indicator status, and life cycle had a significant relationship with colonization or extirpation probability. No dispersal syndromes had a significant relationship with any of the probability estimates. Occupancy, colonization, and extirpation probabilities did not differ between upland and floodplain forests. Overall, robust-design occupancy models work best for calculating probability estimates when species are present in ~11% of sites and are found in a greater number of sampling units (quadrats). Lastly, colonization probabilities were low for many species and were often lower than extirpation probabilities, which suggests decreasing species richness in these communities. Thesis eng https://hdl.handle.net/2142/116059 Copyright 2022 Eric Janssen M.S. Thesis Natural Resources and Environmental Sciences University of Illinois at Urbana-Champaign Natural Res & Env Sci