Global climate change will greatly affect the niche habitats of endemic and specialized species in the tropical rain forests. Most primary endemic and specialized species inhabit the coolest regions of a rainforest, putting them at risk of the rising temperatures accompanying global climate change. To protect them it is important to preserve remaining rainforest and to restore lost cooling regions. Shoo et al. (2011) developed and tested a new model for determining the overall temperatures of tropical regions using elevation, proximity to coast, foliage extent, and other variables. This model will aid in determining what areas are most in need of protection and restoration. The authors discovered a way to quantify natural mechanisms that regulate temperature, allowing them to create a model that will aid conservation efforts in rain forests globally. —Mathew Harreld
Shoo, L. P., Storlie, C., Vanderwal, J., Little, J. and Williams, S. E., 2011. Targeted protection and restoration to conserve tropical biodiversity in a warming world. Global Change Biology 17, 186–193.
The change in global temperature that is causing global climate change has a major impact on species niches and their surrounding environments. Other studies have already determined that there is a large cost to delaying study of and action in preservation of endangered areas (Hannah et al. 2007), and therefore Shoo et al. concluded that a quantitative model was needed to target key climate refuges for future conservation in rain forests. By observing the preferred temperature niches of local species and then finding the mean and range of temperatures for the key regions, Shoo et al. believed they could prioritize the protection and restoration of tropical refuges to maximize future biodiversity in the wake of climate change. Using key geographic traits of areas (i.e. elevation, latitude, distance to stream, distance to coast, foliage cover, clear-sky radiation, cloud offset, and wind exposure) Shoo et al. were able to generate detailed predictions over large spatial scales of temperature variations in the desired region. Shoo et al. ran a trial of this quantitative model on the tropical northeastern Australian rainforest.
They began by measuring local temperature ranges using 12 permanent open-air weather stations, which recorded the 24 hour maximum, and minimum temperatures and 23 weather stations deployed by their team, which recorded the temperature in 15-minute intervals from January 2007 to the end of December 2008. Using independent predictor models, the authors developed a model of spatial surfaces for the region, modeling elevation, latitude, distance to stream, distance to coast, foliage cover, clear-sky radiation, cloud offset, and wind exposure. Then using a linear regression approach for each independent month of recorded data, they developed three equations. The first equation was a base set of predictor variables which included elevation, latitude, distance to stream, distance to coast, foliage cover, clear-sky radiation. The second added on cloud offset, and the third added wind exposure instead of cloud offset. The two extensions to the base model were developed because the authors wanted to see if cloud offset or wind exposure affected the overall data in a significant way, but neither did.
The results of their work showed the utility of a quantitative model to determine future restoration and protection sights for vital cool tropical areas. The three largest determining factors of maximum temperature were elevation, distance to coast, and foliage cover. It is the foliage cover of the rainforest that is the main focus for future conservation efforts. With the model the authors found that in the 8738 km2 of rainforest the average temperature is 27.55°C with a range of 17.32°C to 35.01°C. Shoo et al discovered that 30% of the vertebrates (n=152) in the area live in the first temperature quartile (<25.88°C) and 39% in the second temperature quartile, both with cooler temperatures than for the rest of the vertebrates studied. The vertebrates in the lowest temperature quartile were also the most specialized, and therefore most in danger of climate and temperature shifts. The 62 endemic vertebrates species studied were broken down to 45%, 39%, 16% and 0% for the first, second, third, and forth quartiles respectively, further showing the need for cooler temperature in the region. The first quartile alone covers 2109 km2of the rainforest, and 85% of this is already considered protected area. Another 26% of the rainforest has been cleared or degraded since pre-European settlement. To discover the importance of this lost 26% of the rainforest played had in the regions’ temperature, Shoo et al. modeled the “precleared” temperatures. The average temperature was 29.45°C with a range of 22.55°C to 33.70°C. The team estimated that about 139 km2 of the lost forest was once habitat for the lowest temperature quartile of vertebrate. This leaves a total of 189 km2 of unprotected land, including unprotected land and cleared land.
The rainforest of northeast Australia is a poor model for conservation work because so much of the deforestation has avoided the cooler, more vital regions of the rainforest. But Shoo et al. clearly demonstrate the success of this model’s ability to be a guide for protection and restoration of tropical regions in an effort to preserve biodiversity. Shoo et al. estimate that if 80% of the “precleared” land were restored to its rainforest state that it would dramatically help lower temperatures in that region, aiding nearly half of the species that are home in the coolest regions of rainforest. What is most important about this study is the development of a model that can successfully guide future preservation and restoration projects around the world. In areas of Africa, South America, and Latin America where tropical regions are in danger of human development, the model could prove to be very helpful to determine what areas to protect and restore. The authors helped to reiterate the importance of cool temperature for the diverse, specialized, endemic species in rain forests, and presented a model to aid in their protection. As the world faces further climate change due to human activity this developed model could aid the protection and restoration of biodiversity in tropical regions around the world.