Biology

Sensitivity to climate change for two reptiles at the Mojave

Sensitivity To Climate Change For Two Reptiles At The Mojave An elevated temperature combined with the experienced prolonged droughts over the years seems to push the desert reptiles beyond their psychological limits in as much as their survival is concerned. C.W. Barrows in his journal, “Sensitivity to climate change for two reptiles at the Mojavee Sonoran Desert” tries to unfold this natural phenomena. He narrows down to two reptile species (Gopherus agassizii and Sauromalus ater) inhabiting the Sonoran Desert. In an effort to unearth these findings, C.W. Barrows models the reptile’s niche using the Mahalanobis D2 statistical tool. In order to realize a more predictable niche space he holds terrain and soil variables constant as he varies the climatic variables in a contrast of increasing temperature and decreasing level of precipitation. Recent research has underlined the need to do thorough climatic change predictions. These predictions will help in knowing and anticipating for the undesirable impact on the biodiversity.
C. W Barrows uses this model and in an endeavour brings out some comparison and contrasts between these two species of reptiles. Though they inhabit the same niche, Gopherus agassizii and the common lizard Sauromalus ater present some differences in their elevations and their food dietary. For instance, Sauromalus ater thrive well between an elevation of o to 1830m and a diet which cuts across perennial plants. Their counterparts, Gopherus agassizii thrive well in elevations between o and 1120m. Despite these differences in elevations, there are similarities in their capabilities to live long, their ectothermal definitions and their perennial vegetarian diet. In a conclusive approach, the survival of these two species largely depends on their abilities to adapt to the changing climatic conditions.
Under the guidance of the formulated objective to examine the eminent shifts in habitat for the two species of reptiles, Barrow tries to identify the behavioral and psychological changes adopted by this species as a result of the climate stress. Through these responses and some other mechanisms the reptiles manage to exhibit some differential survival within a certain refugium. C.W. Barrows adopts the following methods and materials in an endeavour to unveil the above mentioned mechanisms and responses. The study area is identified and confined to a 679,585 ha area that includes Joshua Tree National Park and a 10 km buffer that surrounds the Park’s boundary. He also successfully did the niche modeling using the Mahalanobis D2 statistical tool. Through this modeling statistical tool data on these two species was collected from several sources which included local biologists, wildlife observation cards and data development from existing findings within the park amongst several other sources (Barrows, 2011).
By putting the modelling variables in space and constructing a partitioned Mahalanobis D2 model the possibility of bias or overweighting observations was eliminated. These partitioned niche models were then examined to identify the ones with the highest calibration median HIS which was to determine the best niche performing model. C.W. Barrows finalizes this process by performing the modelling climate sensitivity which is achieved by shifting the maximum temperature or the maximum precipitation variables on the greater of Joshua Tree National Park and monitored the effect of this on the two existing species in the park.
According to(Barrows, 2011), by doing the above mentioned modelling activities, C.W. Barrows stumbles upon a fact that the shifts in temperature and precipitation accompanied by decrease in the habitat area in the park and an increase in the elevation levels away from the normal Mojave Sonoran Desert conditions had an effect on the suitable habitats of these two species. The desert tortoises habitat reduced by about 88 percent while that of their counterparts reduced by about 92 percent but it increased by approximately 120 percent in the Mojave Desert conditions.
Finally, through the niche models C.W. Barrows come up with the following survival strategies associated with the two kinds of species of reptiles. Drought strategies include, for instance, a large urinary bladder which has the capability to consume and store large amounts of water, increased time in burrows and&nbsp.reduced activity rates and reduced metabolic rates.&nbsp. Chuckwalla drought strategies included reduced productivity, activity, abandoning social interactions to minimize energy and water loss and the ability to consume a wide variety of diet. this act is an advantage over their counterpart species, Desert tortoise.
References
Barrows.C.W,(2011) Sensitivity to climate change for two reptiles at the Mojave Sonoran Desert Interface Center for Conservation Biology, University of California, Riverside, CA 92521, USA

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