Ivanpah Solar Concentrator, Mojave Desert

Guest essay by Eric Worrall

A new study claims that bird numbers are plummeting in the Mojave Desert region because of climate change. This appears to be occurring despite efforts by local authorities in the region to reduce CO2 emissions by filling the desert with wind turbines and solar concentrators.

Study: Climate change possible cause of bird species decline

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The study shows almost a third of species are less common and widespread now than they once were throughout the region.

The study’s authors, Steven Beissinger and Kelly Iknayan, point to less hospitable conditions in the Mojave Desert as the probable cause.

“California deserts have already experienced quite a bit of drying and warming because of climate change, and this might be enough to push birds over the edge,” said Iknayan, who conducted the research for her doctoral thesis at UC Berkeley. “It seems like we are losing part of the desert ecosystem.”

“The Mojave Desert is now nearly half empty of birds,” said Beissinger, a UC Berkeley professor of environmental science, policy and management. “This appears to be a new baseline, and we don’t know if it’s stable or if it will continue to decline.”

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“Studies elsewhere have found that climate change typically makes places unfavorable for some birds but opens the door for others to come in,” Iknayan said. “In the desert, we are not seeing increases in any of our species except for the common raven. There are a lack of climate change winners in the system.”

Read more: https://www.sfchronicle.com/science/article/Study-Climate-change-possible-cause-of-bird-13167195.php

The abstract of the study;

Collapse of a desert bird community over the past century driven by climate change

Kelly J. Iknayan and Steven R. Beissinger
PNAS August 6, 2018

Climate change has caused deserts, already defined by climatic extremes, to warm and dry more rapidly than other ecoregions in the contiguous United States over the last 50 years. Desert birds persist near the edge of their physiological limits, and climate change could cause lethal dehydration and hyperthermia, leading to decline or extirpation of some species. We evaluated how desert birds have responded to climate and habitat change by resurveying historic sites throughout the Mojave Desert that were originally surveyed for avian diversity during the early 20th century by Joseph Grinnell and colleagues. We found strong evidence of an avian community in collapse. Sites lost on average 43% of their species, and occupancy probability declined significantly for 39 of 135 breeding birds. The common raven was the only native species to substantially increase across survey sites. Climate change, particularly decline in precipitation, was the most important driver of site-level persistence, while habitat change had a secondary influence. Habitat preference and diet were the two most important species traits associated with occupancy change. The presence of surface water reduced the loss of site-level richness, creating refugia. The collapse of the avian community over the past century may indicate a larger imbalance in the Mojave and provide an early warning of future ecosystem disintegration, given climate models unanimously predict an increasingly dry and hot future.

Read more: http://www.pnas.org/content/early/2018/07/31/1805123115

Interesting that a highly intelligent, opportunistic scavenger species like the common raven is doing well, in a region littered with renewable power installations.