Sunday, January 02, 2011

Climate change and Aspen in south-central Idaho

As an certifiable bird nerd and aspiring raptor biologist, I have always known that climate change poses a huge threat to birds, raptors, and essentially most life on the planet. However, I am probably similar to most people in the world by not knowing exactly how this impact will take place. Well, that is changing...

Climate change is not a popular topic today. It seems that most people are more focused on the economy and their jobs and not on the the looming threat of climate change. The onion, one of my favorite satire sites, posted an excellent story a few weeks back: Report: Global Warming Issue From 2 Or 3 Years Ago May Still Be Problem.

As I prepare my master thesis proposal on the breeding ecology of Northern Goshawks, I am uncovering shocking predictions, shocking in both scope and in its timeframe. While I am not pursuing a study of climate change per se, I am studying the impact of climate change upon the ecosystem and specifically upon Northern Goshawk productivity. Work out of the Moscow (Idaho) Forestry Science Laboratory of the Rocky Mountain Research Station of the USDA Forest Service has classified key variables influencing different forest structures. In Rehfeldt et al. (2006) the team developed the generalized models across the western United States. In Rehfeldt et al (2009) the team explored the specific relationship of climate change on Aspen Viability. I am particularly interested in Aspen as all known Northern Goshawk nests in my study area are located in Aspen. The U.S. Forest Service (2003) documented that Aspen within my study area was either "at risk" or "not functioning correctly". I know that some goshawk nest trees have fallen down in the last few years. Thus, I have chosen part of my research effort on understanding what risk Aspen decline has upon the Northern Goshawk in this area.

Rehfeldt et al. (2009) studied which climate predictors were most significant in predicting the presence of Aspen across the west. They found that the annual dryness index, the ratio of summer to annual precipitation, and the interaction of growing season precipitation with the summer-winter temperature differential to be the most significant variables influencing the presence of Aspen. Below is an image of the Aspen viability scores overlaid on my study area, specifically the South Hills and the Albion Mountains. This fairly accurately represents the current range of Aspen in the area. If anything it is very generous in its prediction.

Aspen viability today within the Minidoka Ranger District of the
Sawtooth National Forest based on Rehfeldt et al. (2009).

After showing the predictive power of the climate variables, Rehfeldt et al. (2009) then applied changes predicted by various climate models and scenarios to predict the future viability of Aspen. They chose to use the climate models championed by the US, the UK, and Canada. Upon each of these climate models, they used two different scenarios producing six different predictions. While each of the six predictions are slightly different, they are consistent in one area - Aspen is in trouble in the Minidoka Ranger District! The image below represents the climate model 2.1 from the U. S. Geophysical Fluid Dynamics Laboratory (part of NOAA) combined with the Aspen variables to illustrate the viability of Aspen in the decade surrounding 2030 (a mere 19 years away!).

Aspen viability in 2030 within the Minidoka Ranger District of the
Sawtooth National Forest based on GFDL climate model 2.1 (Rehfeldt et al. 2009).

The 2060 and 2090 predictions aren't worth showing - nothing but red. If these predictions are correct, this will be a tragedy of unfathomable dimensions. Aspen forests are one of the most productive temperate ecosystems. Hundreds of species are dependent upon these forests. Focusing only on raptors, these Aspen forests in the Minidoka Ranger District house Northern Goshawks, Coopers Hawks, Sharp-shinned Hawks, Northern Pygmy Owls, Flammulated Owls, Northern Saw-whet Owls, Great Horned Owls, and probably others. Those are the species that I personally have seen and heard there! Woodpeckers include the Northern Flicker, Hairy Woodpecker, Downy Woodpecker, and Red-knaped Sapsucker. I could go on... Even the State Bird, the Mountain Bluebird lives in Aspen forests. Its a sad, sad story.

I don't know what my call to action is other than to do whatever you can to decrease your carbon dioxide generation.


Rehfeldt, G. E., N. L. Crookston, M. V. Warwell, and J. S. Evans. 2006. Empirical Analyses of Plant-Climate Relationships for the Western United States. International Journal of Plant Science 167: 1123-1150.

Rehfeldt, G. E., D. E. Ferguson, and N. L. Crookston. 2009. Aspen, climate, and sudden decline in western USA. Forest Ecology and Management 258: 2353-2364.

U.S. Forest Service. 2003. Sawtooth National Forest revised land and resource management plan. Sawtooth National Forest. Twin Falls, Idaho USA.


Larry said...

Hi Rob,
Thanks for the grim reality check. I think the problem and its solution, as always, can be found in our evolutionary history. As a species we have never been reproductively rewarded for making decisions based on something that is likely to hit the fan decades into the future. Instead, the rewards come from accruing wealth, status, and offspring as quickly as possible. One of our chief threats during our evolution has been those posed by our human enemies and we therefore spare no expense in pouring resources into our defense. Evolution did not prepare us for greater threats, such as global warming, yet it did equip us with reason, which is our only hope. Using it we might be able to rise above our evolution and act in a way that is contrary to the knee-jerk response so engrained in us. But, one must value, understand, and accept science and reason in order to have any hope. Not many of us do, so the challenge is daunting.

wolf21m said...

Larry, very well said! Thank you for your perspective.

April said...

Thanks for posting this Rob. Larry had a great comment and I heard it echoed on NPR the other day--how humans have evolved to predict and prepare for imminent threats, but we aren't so good at realizing outcomes for our long-term behaviors (e.g. climate change, diet), so we have to struggle to keep these things in the forefront of our minds and retrain ourselves to recalculate risks.

Ruby said...

Interesting post, Rob. I believe every few decades or so, these weather and geodetic structure changes. It scares me to think about it but it is a reality that we should all prepare ourselves and our families for. Sumoservices UK