Here are some details from the Fish and Wildlife Office Public Release.
All three species once thrived in the mountains, but they are now found mostly at high elevations in national parks and public forests in California.
Peer-reviewed government studies found that the Sierra Nevada yellow-legged frog population declined by nearly 70 percent, while the separate mountain yellow-legged frog species declined by more than 80 percent. The Yosemite toad’s population is down about 50 percent.
The service says habitat destruction, climate change and disease are all factors in the decline. [My highlight]
While other moderate and minor level threats including historic logging, mining, grazing pressures and recreational use were evaluated, they were not considered significant factors in our determination,” Jennifer Norris, the service’s Sacramento field supervisor.
Read more HERE.
While some of this maybe factual, one area that I am familiar with is climate change. I have been studying temperature change is the Sierra for over ten years and it is relatively stable. The 5×5 degree gridded data from the Hadley/Climatic Research Unit (CRU) CRUTEM3 database when plotted shows, there has been no statistically significant warming over the last 80 years in the State of California.
I have been reading Jim Steele book Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism. Jim was Director of San Francisco State University’s Sierra Nevada Filed Campus and has spend 25 years improving the environment. He has studied the Sierra extensively, including the changing climate. He writes:
“. . . most USHCN weather stations through out the Sierra Nevada indicate that the climate envelope was converging toward a temperature optimum by lessing both heat and cold stress… the past 60 years of climate change in California should have benefited wildlife.”
This is consistent with the research I did not climate station through out the Sierra. Some of that research can be found HERE. Daytime temperatures have been declining the nigh time temperatures have increased slightly, this should be beneficial to the frogs. Where is the climate impact?
This is from the Federal Register:
When it is too cold, eggs and tadpoles are lost to freezing. This poses a risk as earlier snowmelt is expected to cue breeding earlier in the year, exposing young tadpoles (or eggs) to killing frosts in more variable conditions of early spring (Corn 2005, p. 60). When it is too warm, tadpoles are lost to pool desiccation. Alterations in the annual and seasonal hydrologic cycles that influence water volume and persistence in Yosemite toad breeding areas can thereby impact breeding success.
As Jim Steele noted in the “past 60 years of climate change in California should have benefited wildlife” As I note that in the high Sierra maximum temperatures are declining and night time rising slightly, which should benefit the frogs.
The frogs maybe endangered but it is not from climate change that is not happening in a way to harm the frogs. We are not having more droughts now than in the past, and the over the long term the snow pack stable. Yes, there are ups and downs, but not outside the normal range.
Here is plot from the high Sierra as one example:
Why should you care? Economics. If the Forests are closed to protect the frogs, people will not come to visit and stop in our communities to spend their money. First it was a bait fish in the delta and now a frog in the forest, people you are next once the full implementation of Agenda 21 complete.