Living on the edge: Glucocorticoid physiology in desert iguanas (Dipsosaurus dorsalis) is predicted by distance from an anthropogenic disturbance, body condition, and population density

2020 ◽  
Vol 294 ◽  
pp. 113468 ◽  
Author(s):  
Jessica L. Malisch ◽  
Theodore Garland ◽  
Laurence Claggett ◽  
Lindsey Stevenson ◽  
Ellen A. Kohl ◽  
...  
2020 ◽  
Vol 84 (5) ◽  
pp. 938-947
Author(s):  
Pascale Ayotte ◽  
Mael Le Corre ◽  
Steeve D. Côté

2015 ◽  
Vol 308 (6) ◽  
pp. R449-R454 ◽  
Author(s):  
Amy E. M. Newman ◽  
Nicholas B. Edmunds ◽  
Shannon Ferraro ◽  
Quentin Heffell ◽  
Gillian M. Merritt ◽  
...  

Conspecific density is widely recognized as an important ecological factor across the animal kingdom; however, the physiological impacts are less thoroughly described. In fact, population density is rarely mentioned as a factor in physiological studies on captive animals and, when it is infrequently addressed, the animals used are reared and housed at densities far above those in nature, making the translation of results from the laboratory to natural systems difficult. We survey the literature to highlight this important ecophysiological gap and bring attention to the possibility that conspecific density prior to experimentation may be a critical factor influencing results. Across three taxa: mammals, birds, and fish, we present evidence from ecology that density influences glucocorticoid levels, immune function, and body condition with the intention of stimulating discussion and increasing consideration of population density in physiology studies. We conclude with several directives to improve the applicability of insights gained in the laboratory to organisms in the natural environment.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jens J. Currie ◽  
Martin van Aswegen ◽  
Stephanie H. Stack ◽  
Kristi L. West ◽  
Fabien Vivier ◽  
...  

AbstractUnderstanding the impacts of foraging disruptions to odontocete body condition is fundamental to quantifying biological effects of human disturbance and environmental changes on cetacean populations. Here, reductions in body volume of free-ranging pygmy killer whales (Feresa attenuata) were calculated using repeated measurements of the same individuals obtained through Unoccupied Aerial System (UAS)-photogrammetry during a prolonged disruption in foraging activity arising from a 21-day stranding event. Stranded individuals were used to verify UAS-derived volume and length estimates through 3D-imaging, water displacement, and post-mortem measurements. We show that (a) UAS estimates of length were within 1.5% of actual body length and UAS volume estimates were within 10–13% of actual volume, (b) foraging disruption resulted in a daily decrease of 2% of total body mass/day, and (c) pygmy killer whales can lose up to 27% of their total body weight within 17 days. These findings highlight the use of UAS as a promising new method to remotely monitor changes in body condition and animal health, which can be used to determine the potential effects of anthropogenic disturbance and environmental change on free-ranging odontocetes.


The Condor ◽  
2018 ◽  
Vol 120 (3) ◽  
pp. 566-580 ◽  
Author(s):  
Daniel Gibson ◽  
Melissa K. Chaplin ◽  
Kelsi L. Hunt ◽  
Meryl J. Friedrich ◽  
Chelsea E. Weithman ◽  
...  

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Enrico Lunghi ◽  
Raoul Manenti ◽  
Manuela Mulargia ◽  
Michael Veith ◽  
Claudia Corti ◽  
...  

Oryx ◽  
2017 ◽  
Vol 53 (4) ◽  
pp. 643-653 ◽  
Author(s):  
Andrew J. Hearn ◽  
Joanna Ross ◽  
Henry Bernard ◽  
Soffian A. Bakar ◽  
Benoit Goossens ◽  
...  

AbstractExtensive areas of tropical forests have been, and continue to be, disturbed as a result of selective timber extraction. Although such anthropogenic disturbance typically results in the loss of biodiversity, many species persist, and their conservation in production landscapes could be enhanced by a greater understanding of how biodiversity responds to forest management practices. We conducted intensive camera-trap surveys of eight protected forest areas in Sabah, Malaysian Borneo, and developed estimates of Sunda clouded leopard Neofelis diardi population density from spatially explicit capture–recapture analyses of detection data to investigate how the species’ abundance varies across the landscape and in response to anthropogenic disturbance. Estimates of population density from six forest areas were 1.39–3.10 individuals per 100 km2. Our study provides the first evidence that the population density of the Sunda clouded leopard is negatively affected by hunting pressure and forest fragmentation, and that among selectively logged forests, time since logging is positively associated with abundance. We argue that these negative anthropogenic impacts could be mitigated with improved logging practices, such as reducing the access of poachers by effective gating and destruction of road access points, and by the deployment of anti-poaching patrols. By calculating a weighted mean population density estimate from estimates developed here and from the literature, and by extrapolating this value to an estimate of current available habitat, we estimate there are 754 (95% posterior interval 325–1,337) Sunda clouded leopards in Sabah.


2012 ◽  
Vol 90 (7) ◽  
pp. 868-874 ◽  
Author(s):  
A.J. White ◽  
R.G. Poulin ◽  
B. Wissel ◽  
J.L. Doucette ◽  
C.M. Somers

Habitat conversion is among the most important causes of environmental change worldwide, yet relatively little is known about its potential influence on trophic interactions. We investigated the effects of agricultural land use on carbon and nitrogen stable isotope values, trophic status, population density, and body condition of deer mice ( Peromyscus maniculatus (Wagner, 1845)) in a grassland ecosystem. Muscle δ15N (cropland = 7.6‰ ± 1.3‰; hay fields = 7.9‰ ± 1.3‰; native prairie = 7.2‰ ± 2.1‰) from deer mice did not vary with land use despite baseline soil and vegetation δ15N differences. Enrichment of deer mice over vegetation (Δδ15N) was, on average, a full trophic level (~2.5‰) higher on native prairie (6.4‰ ± 1.6‰) than on cropland (3.9‰ ± 2.3‰), and intermediate in hay fields (5.9‰ ± 2.0‰). Relative density of deer mice was more than twofold higher in crop and hay fields compared with native prairie, but body condition did not vary with land use. Our results suggest that agricultural activity caused a shift in the trophic level and relative abundance of a generalist grassland omnivore. Soil and vegetation δ15N reflected anthropogenic N inputs to agricultural fields but were not useful as general markers of habitat use in this study.


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