[MCN] 8 grizzly bear-related issues including climate change [ heat ]

[Lance Olsen]

1— “Schwartz and others (2010) found that grizzly bear survival in the Greater Yellowstone Ecosystem declined as road density, number of homes, and site developments increased.”

Flathead National Forest Biological Assessment, December 2017 p. 104

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2 — ”   …  housing growth poses the main threat to protected areas in the United States whereas deforestation is the main threat in developing countries."
 
Volker C. Radeloff, Susan I. Stewart et al. Housing growth in and near United States protected areas limits their conservation value. 

PNAS. January 12, 2010. 
http://www.pnas.org/content/107/2/940.abstract?sid=4718e5e2-8fa3-475a-9b92-032f399600c3 <http://www.pnas.org/content/107/2/940.abstract?sid=4718e5e2-8fa3-475a-9b92-032f399600c3>

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3 — PUBLIC RELEASE: 5-APR-2018
Researchers provide potential explanation for declines in brown bear populations

Animals may fall into what are called evolutionary and ecological traps when they make poor decisions using seemingly reliable environmental cues. For example, animals may select habitats to occupy based on food availability, but mortality may be highest in habitats with the highest food availability. A new Mammal Review <https://onlinelibrary.wiley.com/journal/13652907> article examines how the brown (grizzly) bear can fall into such traps in human-modified landscapes, which may contribute to decreases in brown bear populations.

In their article, researchers describe evolutionary and ecological traps for brown bears, and they propose mechanisms by which traps may affect the dynamics and viability of brown bear populations. There are six potential trap scenarios: food resources close to human settlements; agricultural landscapes; roads; artificial feeding sites; hunting by humans; and other human activities (including ecotourism and reindeer husbandry).

"Despite the interest in large carnivore conservation in human-modified landscapes, the emergence of traps and their potential effects on the conservation of large carnivore populations has frequently been overlooked," said lead author Dr. Vincenzo Penteriani, of the Spanish National Research Council (CSIC), in Spain. "More effort should thus be put into the consideration that traps may be behind the unexpected decreases of brown bear and other large carnivore populations in human-modified landscapes."

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4— 3 definitions of ecological traps

1st definition — Ecological traps are part of a broader phenomenon, evolutionary traps, involving a dissociation between cues that organisms use to make any behavioral or life-history decisions.

However, in environments that have been altered suddenly by humans, formerly reliable cues might no longer be associated with adaptive outcomes. …

by MA Schlaepfer · ‎2002 · 
‎Cited by 1320 · ‎https://www.sciencedirect.com/science/article/abs/pii/S0169534702025806 <https://www.sciencedirect.com/science/article/abs/pii/S0169534702025806>

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2nd definition — When Good Animals Love Bad Habitats

Ecological trap theory suggests that, under most circumstances, the presence of a trap in a landscape will drive a local population to extinction. 
by J BATTIN · ‎2004 ·
‎Cited by 1033 http://lithornis.nmsu.edu/~phoude/ecological%20traps.pdf <http://lithornis.nmsu.edu/~phoude/ecological%20traps.pdf> 

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3rd definition— Don't Be an Ecological Trap | Habitat Network

May 6, 2011 — But buyer beware, because such habitats are called ecological traps, meaning that animals that try to live in them get hoodwinked.
content.yardmap.org <http://content.yardmap.org/> › learn › dont-be-an-ecological-trap

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5 — Mora (2014) argues that human population size, “...despite being directly or indirectly linked to the deterioration of ecological systems and a key factor for the success of conserving species and ecosystems, has been rarely considered and in fact ‘trivialized or ignored’ by much of the conservation biology community.” 

Mora, C. 2014. Revisiting the environmental and socioeconomic effects of population growth: a fundamental but fading issue in modern scientific, public, and political circles. Ecology and Society 19(1): 38. 
http://dx.doi.org/10.5751/ES-06320-190138

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6 — Functional Ecology First published: 10 January 2021
https://doi.org/10.1111/1365-2435.13727 <https://doi.org/10.1111/1365-2435.13727>

Thermal constraints on energy balance, behaviour and spatial distribution of grizzly bears
Savannah A. Rogers <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Rogers%2C+Savannah+A>  Charles T. Robbins <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Robbins%2C+Charles+T>  Paul D. Mathewson <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Mathewson%2C+Paul+D>  Anthony M. Carnahan <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Carnahan%2C+Anthony+M>  Frank T. van Manen <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Manen%2C+Frank+T>  Mark A. Haroldson <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Haroldson%2C+Mark+A>  Warren P. Porter <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Porter%2C+Warren+P>  Taylor R. Rogers <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Rogers%2C+Taylor+R>  Terence Soule <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Soule%2C+Terence>  Ryan A. Long <https://besjournals.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Long%2C+Ryan+A>

Abstract

Heat dissipation limit theory posits that energy available for growth and reproduction in endotherms is limited by their ability to dissipate heat. In mammals, endogenous heat production increases markedly during gestation and lactation, and thus female mammals may be subject to greater thermal constraints on energy expenditure than males. Such constraints likely have important implications for behaviour and population performance in a warming climate.
We used a mechanistic simulation model based on the first principles of heat and mass transfer to study thermal constraints on activity (both timing and intensity) of captive female grizzly bears Ursus arctos in current and future climate scenarios. We then quantified the relative importance of regulatory behaviours for maintaining heat balance using GPS telemetry locations of lactating versus non‐lactating female bears from Yellowstone National Park, and assessed the degree to which costs of thermoregulation constrained the distribution of sampled bears in space and time.
Lactating female bears benefitted considerably more from behavioural cooling mechanisms (e.g. partial submersion in cool water or bedding on cool substrate) than non‐lactating females in our simulations; the availability of water for thermoregulation increased the number of hours during which lactating females could be active by up to 60% under current climatic conditions and by up to 43% in the future climate scenario. Moreover, even in the future climate scenario, lactating bears were able to achieve heat balance 24 hr/day by thermoregulating behaviourally when water was available to facilitate cooling.
The most important predictor of female grizzly bear distribution in Yellowstone, regardless of reproductive status, was elevation. However, variables associated with the thermal environment were relatively more important for predicting the distribution of lactating than non‐lactating female bears.
Our results suggest that the costs of heat dissipation, which are modulated by climate, may impose constraints on the behaviour and energetics of large endotherms like grizzly bears, and that access to water for cooling will likely be an increasingly important driver of grizzly bear distribution in Yellowstone as the climate continues to warm.

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7—  Ursus, 27(2) : 129-135 Published By: International Association for Bear Research and Management
https://doi.org/10.2192/URSU-D-16-00010.1 <https://doi.org/10.2192/URSU-D-16-00010.1>

American black bear thermoregulation at natural and artificial water sources 
Michael A. Sawaya, Alan B. Ramsey, and Philip W. Ramsey

Abstract: Water is essential for hydration in American black bears (Ursus americanus) and other species; however, its role in thermoregulation is poorly understood. In 2010, we established a network of remote cameras to monitor wildlife in the Bitterroot Valley, Montana, USA. One of our objectives was to document and describe American black bear behavior at natural and artificial water sources. We detected male and female adult, subadult, and cub of year black bears immersing in water sources to thermoregulate. Bear use was concentrated at one livestock tank, one road puddle, and one pond in areas with relatively little human disturbance. Bear use steadily increased over summer, peaking in late summer when ambient temperatures were high and fat layers were thick. Our results demonstrate that water is an important thermoregulatory resource for some bear populations, though more research is needed to understand how ursids use behavioral thermoregulation to dissipate excess body heat and avoid hyperthermia.

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8— “Droughts of the twenty-first century are characterized by hotter temperatures, longer duration, and greater spatial extent …. This situation increases the vulnerability of ecosystems to drought, including a rise in drought-driven tree mortality globally (Allen et al. 2015) and anticipated ecosystem transformations from one state to another—for example, forest to a shrubland (Jiang et al. 2013). When a drought drives changes within ecosystems, there can be a ripple effect ….” 

Crausbay, et al. Defining Ecological Drought for the Twenty-First Century. Bulletin of the American Meteorological Society. December 2017.

Open Access
https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-16-0292.1 


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“… the serious meaning in a concept lies in the difference it will make to someone if it is true.”

William James (1842 –1910)
Pragmatism. Meridian Books, 1955

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