[MCN] Drought & wildlife: Jaguars do better where it's wetter

[Lance Olsen]

Biological Conservation Volume 206, February 2017, Pages 132 142
http://dx.doi.org/10.1016/j.biocon.2016.09.027

Predicting carnivore distribution and extirpation rate based on human 
impacts and productivity factors; assessment of the state of jaguar 
(Panthera onca) in Venezuela
WBodzimierz Jdrzejewski et al

Highlights

"Carnivores depend on joint effects of anthropogenic and environmental factors.

"Jaguars disappear faster in dry, unproductive areas.

"Chances of persistence are higher in humid and productive areas.

"Carnivore declines cannot be predicted from human density alone.

Abstract
http://www.sciencedirect.com/science/article/pii/S0006320716304748

The worldwide decline in carnivore populations has been attributed to 
various human impacts. However, our understanding of the mechanisms 
behind these declines is insufficient to predict the timing and 
location of local extinctions. We collected data on presence/absence 
and time since extirpation of jaguars across Venezuela. To test if 
human impacts or ecosystem productivity better explain the observed 
spatial variation in probability of jaguar occurrence we compared 
logistic regression models fit with different combinations of 
anthropogenic and environmental variables. Similarly, we modelled the 
time since extirpation, using a multiple regression approach. Our 
study supported the hypothesis that jaguar extirpations and 
distribution are determined by a joint effect of anthropogenic 
factors and environmental variables, mainly those related with 
ecosystem productivity. Human population density and habitat 
alterations exerted strong negative effects on jaguar populations, 
while annual precipitation, mean temperature, forest cover, primary 
productivity, and other vegetation indices had positive effects. The 
strength of human impact is shaped by ecosystem productivity: jaguars 
disappear faster in dry, unproductive areas, and survive better in 
humid, productive areas even when human densities are higher. We 
estimated that jaguars in Venezuela have been extirpated from 
approximately 26% of the territory of Venezuela; present jaguar range 
covers approximately 66% of the country. We demonstrate that human 
population density alone cannot adequately explain past extirpations 
nor predict future jaguar declines. We conclude that the predicted 
future growth of the human population will not necessarily determine 
jaguar declines, and proper management and conservation programs 
could potentially prevent jaguar extirpations.


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"We describe the "landscape trap" concept, whereby entire landscapes 
are shifted into, and then maintained (trapped) in, a highly 
compromised structural and functional state as the result of mul- 
tiple temporal and spatial feedbacks between human and natural 
disturbance regimes."

David B. Lindenmayer et al. Newly discovered landscape traps produce 
regime shifts in wet forests PNAS Early Edition 
www.pnas.org/cgi/doi/10.1073/pnas.1110245108
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"Challenges in predicting responses of individual tree species to 
climate are a result of species competing under a climate regime that 
we have not seen before and they may not have experienced before."

Fred L. Bunnell & Laurie L. Kremsater. Migrating Like a Herd of Cats: 
Climate Change and Emerging Forests in British Columbia. Journal of 
Ecosystems and Management 13(2):1-24 2012.


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