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Title:Demography of the spotted turtle (clemmys guttata) in Illinois
Author(s):Feng, Christina Yen
Advisor(s):Dreslik, Michael J.
Contributor(s):Phillips, Christopher A.; Suski, Cory D.
Department / Program:Natural Res & Env Sci
Discipline:Natural Res & Env Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Spotted Turtle
Clemmys guttata
Abstract:The Spotted Turtle (Clemmys guttata) has been well-documented and studied at two locations in Will County, Illinois, since 1987. Although spatial and reproductive ecology are relatively well understood, there remains no comprehensive demographic analysis of the two populations. I investigated the population size, structure, and demographic behavior of C. guttata populations at Lockport and Romeoville Prairie Nature Preserves by supplementing an existing dataset by conducting capture-mark-recapture in 2015–2016. I used the subsequent capture and reproductive data spanning 1988–2016 and Package RMark to analyze deterministic measures of change for both populations. Both populations exhibited an even sex ratio, a strong bias towards adults, and positive growth over the length of the study. I used a POPAN model to estimate the population size to be 116 individuals in 2010 at Romeoville and 99 individuals in 2016 at Lockport. I employed the CJSRandom model in RMark to determine age-specific survival and coupled the estimates with age-specific fecundity to create a female-only, deterministic Leslie matrix model for each population and subsequently conducted a perturbation analysis and population projection. Population growth was most sensitive to survival rates for the youngest age class and most elastic to pre-adult survival for both populations, which corroborates results on C. guttata from the species’ northern range limit and contradicts the general trend for long-lived turtle species. Neither population appears demographically viable in the long-term although their short-term dynamics appear stable.
Issue Date:2018-03-09
Rights Information:Copyright 2018 Christina Feng
Date Available in IDEALS:2018-09-04
Date Deposited:2018-05

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