TY - JOUR
T1 - Blanding's Turtle Demography and Population Viability
AU - King, Richard B.
AU - Golba, Callie K.
AU - Glowacki, Gary A.
AU - Kuhns, Andrew R.
N1 - Funding Information:
Funding for this project was provided by the U.S. Fish and Wildlife Service – Great Lakes Fish and Wildlife Restoration Act (FWS Agreement Number F16AP01040), the Illinois Department of Natural Resources (State Wildlife Grant T-111-R-1), Lake County Forest Preserve District, and Northern Illinois University. Work was carried out under permits from the Illinois Department of Natural Resources (05-11s, 07-04s, 16-045). Institutional Animal Care and Use Committee approval was provided by Northern Illinois University (LA16-0015) and the University of Illinois (06129). We thank field technicians, Lake County Forest Preserve District staff, interns, and volunteers for their contributions to field surveys. We are grateful to D. Bradke, B. Crawford, R. Lacy, J. Maerz, P. Miller, J. Vanek, and three anonymous reviewers for their very constructive suggestions to improve the manuscript.
Funding Information:
Funding for this project was provided by the U.S. Fish and Wildlife Service - Great Lakes Fish and Wildlife Restoration Act (FWS Agreement Number F16AP01040), the Illinois Department of Natural Resources (State Wildlife Grant T-111-R-1), Lake County Forest Preserve District, and Northern Illinois University. Work was carried out under permits from the Illinois Department of Natural Resources (05-11s, 07-04s, 16-045). Institutional Animal Care and Use Committee approval was provided by Northern Illinois University (LA16-0015) and the University of Illinois (06129). We thank field technicians, Lake County Forest Preserve District staff, interns, and volunteers for their contributions to field surveys. We are grateful to D. Bradke, B. Crawford, R. Lacy, J. Maerz, P. Miller, J. Vanek, and three anonymous reviewers for their very constructive suggestions to improve the manuscript. Any use of trade, product, website, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Publisher Copyright:
© 2021 U.S. Fish and Wildlife Service. All rights reserved.
PY - 2021/6
Y1 - 2021/6
N2 - In anticipation of U.S. federal status classification (warranted, warranted but precluded, not warranted), scheduled for 2023, we provide population viability analysis of the Blanding's turtle Emydoidea blandingii, a long-lived, late-maturing, semi-aquatic species of conservation concern throughout its range. We present demographic data from long-term study of a population in northeastern Illinois and use these data as the basis for viability and sensitivity analyses focused on parameter uncertainty and geographic parameter variation. We use population viability analysis to identify population sizes necessary to provide population resiliency to stochastic disturbance events and catastrophes, and demonstrate how alternative definitions of 'foreseeable future' might affect status decisions. Demographic parameters within our focal population resulted in optimistic population projections (probability of extinction = 0% over 100 y) but results were less optimistic when catastrophes or uncertainty in parameter estimates were incorporated (probability of extinction = 3% and 16%, respectively). Uncertainty in estimates of age-specific mortality had the biggest impact on population viability analysis outcomes but uncertainty in other parameters (age of first reproduction, environmental variation in age-specific mortality, percent of females reproducing, clutch size) also contributed. Blanding's turtle demography varies geographically and incorporating this variation resulted in both mortality- and fecundity-related parameters affecting population viability analysis outcomes. Possibly, compensatory variation among demographic parameters allows for persistence across a wide range of parameter values. We found that extinction risk decreased and retention of genetic diversity increased rapidly with increasing initial population size. In the absence of catastrophes, demographic conservation goals could be met with a smaller initial population size than could genetic conservation goals; ≥20-50 adults were necessary for extinction risk,5%, whereas ≥50-110 adults were necessary to retain.95% of existing genetic diversity over 100 y. These thresholds shifted upward when catastrophes were included; ≥50-200 adults were necessary for extinction risk,5% and ≥110 to.200 adults were necessary to retain.95% of existing genetic diversity over 100 y. Impediments to Blanding's turtle conservation include an incomplete understanding of geographic covariation among demographic parameters, the large amount of effort necessary to estimate and monitor abundance, and uncertainty regarding the impacts of increasingly frequent extreme weather events.
AB - In anticipation of U.S. federal status classification (warranted, warranted but precluded, not warranted), scheduled for 2023, we provide population viability analysis of the Blanding's turtle Emydoidea blandingii, a long-lived, late-maturing, semi-aquatic species of conservation concern throughout its range. We present demographic data from long-term study of a population in northeastern Illinois and use these data as the basis for viability and sensitivity analyses focused on parameter uncertainty and geographic parameter variation. We use population viability analysis to identify population sizes necessary to provide population resiliency to stochastic disturbance events and catastrophes, and demonstrate how alternative definitions of 'foreseeable future' might affect status decisions. Demographic parameters within our focal population resulted in optimistic population projections (probability of extinction = 0% over 100 y) but results were less optimistic when catastrophes or uncertainty in parameter estimates were incorporated (probability of extinction = 3% and 16%, respectively). Uncertainty in estimates of age-specific mortality had the biggest impact on population viability analysis outcomes but uncertainty in other parameters (age of first reproduction, environmental variation in age-specific mortality, percent of females reproducing, clutch size) also contributed. Blanding's turtle demography varies geographically and incorporating this variation resulted in both mortality- and fecundity-related parameters affecting population viability analysis outcomes. Possibly, compensatory variation among demographic parameters allows for persistence across a wide range of parameter values. We found that extinction risk decreased and retention of genetic diversity increased rapidly with increasing initial population size. In the absence of catastrophes, demographic conservation goals could be met with a smaller initial population size than could genetic conservation goals; ≥20-50 adults were necessary for extinction risk,5%, whereas ≥50-110 adults were necessary to retain.95% of existing genetic diversity over 100 y. These thresholds shifted upward when catastrophes were included; ≥50-200 adults were necessary for extinction risk,5% and ≥110 to.200 adults were necessary to retain.95% of existing genetic diversity over 100 y. Impediments to Blanding's turtle conservation include an incomplete understanding of geographic covariation among demographic parameters, the large amount of effort necessary to estimate and monitor abundance, and uncertainty regarding the impacts of increasingly frequent extreme weather events.
KW - Emydoidea blandingii
KW - Environmental variance
KW - Extinction risk
KW - Population size
KW - PVA
KW - Sensitivity analysis
KW - Survival
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U2 - 10.3996/JFWM-20-063
DO - 10.3996/JFWM-20-063
M3 - Article
AN - SCOPUS:85113923341
VL - 12
SP - 112
EP - 138
JO - Journal of Fish and Wildlife Management
JF - Journal of Fish and Wildlife Management
SN - 1944-687X
IS - 1
ER -