TY - JOUR
T1 - Living on the edge
T2 - Glucocorticoid physiology in desert iguanas (Dipsosaurus dorsalis) is predicted by distance from an anthropogenic disturbance, body condition, and population density
AU - Malisch, Jessica L.
AU - Garland, Theodore
AU - Claggett, Laurence
AU - Stevenson, Lindsey
AU - Kohl, Ellen A.
AU - John-Alder, Henry B.
N1 - Funding Information:
We would like to thank three anonymous reviewers whose comments improved the manuscript. We thank W. Hodges for assistance in the field and help with experimental design. We also thank Robert Cox for lab assistance during hormone analyses. Funding for this project was provided through a Shipley-Skinner Grant awarded to JLM through The Center for Conservation Biology at UCR. JLM is currently supported by a fellowshio from the American Association of University Women. This work was approved by UCR-IACUC and covered by a CDFG scientific collection permit to JLM.
Funding Information:
We would like to thank three anonymous reviewers whose comments improved the manuscript. We thank W. Hodges for assistance in the field and help with experimental design. We also thank Robert Cox for lab assistance during hormone analyses. Funding for this project was provided through a Shipley-Skinner Grant awarded to JLM through The Center for Conservation Biology at UCR. JLM is currently supported by a fellowshio from the American Association of University Women. This work was approved by UCR-IACUC and covered by a CDFG scientific collection permit to JLM.
Publisher Copyright:
© 2020 Elsevier Inc.
PY - 2020/8/1
Y1 - 2020/8/1
N2 - Ecological factors, such as habitat quality, influence the survival and reproductive success of free-living organisms. Urbanization, including roads, alters native habitat and likely influences physiology, behavior, and ultimately Darwinian fitness. Some effects of roads are clearly negative, such as increased habitat fragmentation and mortality from vehicle collision. However, roads can also have positive effects, such as decreasing predator density and increased vegetation cover, particularly in xeric habitats due to increased water run-off. Glucocorticoids are metabolic hormones that reflect baseline metabolic needs, increase in response to acute challenges, and may mediate endogenous resource trade-offs between survival and reproduction. Here we examined circulating concentrations of corticosterone (baseline and stress-induced) in desert iguanas (Dipsosaurus dorsalis) in relation to the distance from a major anthropogenic disturbance, a high-traffic road in Palm Springs, CA. Additionally, we analyzed body condition and population density as additional predictors of glucocorticoid physiology. Surprisingly, we found lower baseline CORT levels closer to the road, but no effect of distance from road on stress-induced CORT or stress responsiveness (difference between baseline and stress-induced concentrations). Both population density and body condition were negative predictors of baseline CORT, stress-induced CORT, and stress responsiveness. Given the known effect of roads to increase run-off and vegetation density, increased water availability may improve available forage and shade, which may then increase the carrying capacity of the habitat and minimize metabolic challenges for this herbivorous lizard. However, it is important to recognize that surfaces covered by asphalt are not usable habitat for iguanas, likely resulting in a net habitat loss.
AB - Ecological factors, such as habitat quality, influence the survival and reproductive success of free-living organisms. Urbanization, including roads, alters native habitat and likely influences physiology, behavior, and ultimately Darwinian fitness. Some effects of roads are clearly negative, such as increased habitat fragmentation and mortality from vehicle collision. However, roads can also have positive effects, such as decreasing predator density and increased vegetation cover, particularly in xeric habitats due to increased water run-off. Glucocorticoids are metabolic hormones that reflect baseline metabolic needs, increase in response to acute challenges, and may mediate endogenous resource trade-offs between survival and reproduction. Here we examined circulating concentrations of corticosterone (baseline and stress-induced) in desert iguanas (Dipsosaurus dorsalis) in relation to the distance from a major anthropogenic disturbance, a high-traffic road in Palm Springs, CA. Additionally, we analyzed body condition and population density as additional predictors of glucocorticoid physiology. Surprisingly, we found lower baseline CORT levels closer to the road, but no effect of distance from road on stress-induced CORT or stress responsiveness (difference between baseline and stress-induced concentrations). Both population density and body condition were negative predictors of baseline CORT, stress-induced CORT, and stress responsiveness. Given the known effect of roads to increase run-off and vegetation density, increased water availability may improve available forage and shade, which may then increase the carrying capacity of the habitat and minimize metabolic challenges for this herbivorous lizard. However, it is important to recognize that surfaces covered by asphalt are not usable habitat for iguanas, likely resulting in a net habitat loss.
KW - Body condition
KW - Conservation physiology
KW - Corticosterone
KW - Desert iguana
KW - Glucocorticoids
KW - Road ecology
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U2 - 10.1016/j.ygcen.2020.113468
DO - 10.1016/j.ygcen.2020.113468
M3 - Article
C2 - 32201233
AN - SCOPUS:85082849047
VL - 294
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
SN - 0016-6480
M1 - 113468
ER -