“Nature is not more complicated than you think, it is more complicated than you CAN think.” ~Frank Edwin Egler

I thought there might be a temperature window last weekend to go back up and hike the Deer Springs trail near Idyllwild last weekend. The temperatures were good, but alas, the Forest Service had closed ALL their trails due to the severe wildfire threats. If a wildfire did ignite, it would be nearly impossible to find all the hikers and get them to safety. Good choice on their part, but darned inconvenient for me. However, not to allow that to tarnish my day, I turned lemons into lemonade and crossed the street to hike the Idyllwild Nature Center/County Park. Their trails were open, and away I went. I had had it in the back of my mind to hike the county park trails at some point, and that point was last Sunday.

The Deer Springs trail has long been one of our annual lizard survey routes, aimed at tracking the shifting distributions of the five species of lizards that we commonly encounter there. The idea is to track their responses to climate change. After seven or eight years of surveys I felt we were dialing in the upper and lower boundaries for each species, and so could with some confidence say that differences from one year to the next were real and not an artifact of insufficient data.

The lizard with the highest elevation range, the southern sagebrush lizard, didn’t reliably show up along the trail until about 1870-1900 m (roughly 6,000’). This is the same lizard you see at the top of the tram; they can occur there to nearly 9,000’. Southern sagebrush lizards are almost indistinguishable from “regular” sagebrush lizards and are lumped together in most field guides. But the regular sagebrush lizards live in, you guessed it, sagebrush – Great Basin Desert habitats. Southern sagebrush lizards are confined to high elevation conifer forests of southern California and northern Baja. I can imagine that the early sagebrush lizards got pushed down here during each successive ice age of the Pleistocene; during the intervening warm periods they moved back north, except some moved up into the mountains and became permanently isolated from their cousins. The two sagebrush lizards will never meet again, and their DNA makes it very clear that they are distinct lineages. The field guides just haven’t caught up with the science. 

But last year my assumption about what I thought I knew about lower boundaries to their range was shaken. My son and daughter-in-law (Colin and Sendy, CalNat class of 2018) got married at that same county park last fall (2019). While setting up lights and decorations for their big event, as is often the case, I got distracted by lizards. When I got a good look at them I saw that they were southern sagebrush lizards, but there the elevation was closer to 5,500’, a good 500’ lower than I found them on just the other side of the street. I made a mental note to go back and try to see just what was going on with this species.

As I now can report, southern sagebrush lizards are very common in the county park, with lots of hatchlings this time of year, and I did find a “new” hard lower boundary at 1668 m (5340’). Below that boundary there were only fence lizards and side-blotched lizards; above that boundary all three species were common. That still leaves a question; why is there such a gap between either side of the highway where southern sagebrush lizards seem to be absent? I think the answer can be found by understanding how the complex terrain of our mountains create microclimates. 

Climate scientists who model how modern climate change will warm our planet necessarily simplify the earth’s surface to be a smooth sphere. Of course, it isn’t smooth at all. There are steep mountains and low valleys with north face and south facing slopes. Elevation, steepness and slope direction all create microclimates. Where an open, south facing slope might be too hot and dry to support some species. A steeper north facing slope might be very comfortable for those species, even at lower elevations. Then there are narrow canyons that drain cold air from upper slopes. All this complexity ends up creating habitats for animals and plants.

Nature may be more complicated than we can think, but we can whittle away at the edges and in doing so get closer and closer to understanding that mystery of mysteries.

Check out the attached images of a hatchling and several adult southern sagebrush lizards.