Croaking?

Are amphibians croaking? Well, that is not my bag but some have suggested that mean old climate might merit a position in the lineup of suspects. So, the chair of the IUCN Declining Amphibian Task Force Climate and Atmospheric Working Group (CAWG), invited me to their workshop dealing with global climate change and how this may affect amphibian populations. Corvallis is a nice place and I said yes so CED readers will have to listen-up as well. Besides, they said I could present a half hour talk on global climate change "covering any aspect of global climate change that you wish to cover." It was my good luck that we (myself and a former student David Scott) already had some amphib-climate research finished and on the shelf to spice up my contributions on the climate as it has changed since the mid-1800s. Now I could better talk about amphibian and reptilian climates and put climate change into some context.

Cold blooded reptiles and amphibians are at the mercy of climate. They are nice little and sometimes big thermodynamic wicks. To keep cool one of these little wicks specializes in latent energy flux (amphibs.) and the other in sensible energy flux (reps.). For staying warm both of these thermodynamic wicks rely on a sensible heat flux from warm air and photons from the sun. Reptiles and amphibians should then have fundamentally different climatic windows. And looking through these two climatic windows you should see different visions of biodiversity. Our research task was to quantify those windows and have a look through them.

We rounded up my climate data for 579 grid cells the size of Rhode Island all of which were east of the longitude of Albuquerque, New Mexico. Using maps of the home ranges of all US. lizards and salamanders we counted the number of species of each found in each grid cell. For each grid cell we had species richness numbers for lizards and salamanders.

Our climate data included the following variables annual solar radiation load, annual precipitation, winter precipitation, the average number of months where continental tropical air was present at least 50% of the time, the average number of months where maritime tropical air was present at least 50% of the time, precipitation minus potential evapotranspiration, elevation and annual temperature. With the two species counts per grid cell we had 10 variables for each grid cell. It was a 10 x 579 matrix that we subjected to principal components analysis. The vectors that resulted were salamander-lizard, biodiversity-climate vectors.

Component #1: Lizards vs Salamanders

Component #2: Lizard Eden

Component #3: Salamander Eden

If our world warms due to carbon dioxide enrichment we would expect the following: a warmer, wetter, cloudier world with more rain. Tropical air masses like maritime tropical and continental tropical air should be more frequent or more highly developed and Arctic and continental polar air masses less well developed (not like this year) and less frequent. If climate in anyway supports biodiversity, a global warmed world should favor salamanders and lizards. Perhaps an amphibian and reptilian Eden.