Throughout evolutionary history, species have had to adapt to changes in temperature in their habitats to be able to survive. However, the changes in temperature as a result of current climate change may be too fast for species to be able to adapt effectively. The loss of these species would cause large gaps in the “tree of life” diagram which illustrates the relationships of different species throughout history. Thullier et al. (2011) studied the effects of climate change on the diversity of plant, mammal, and bird species across Europe. A variety of models and forecasts were utilized to find that the vulnerability of species to the effects of climate change is not strongly linked by close relation or proximity on the tree of life diagram. Thullier et al. also found that in the future, species diversity will decrease in Southern Europe, but increase in Northern Europe. Despite the increases in diversity in the North, the decreases will be strong enough to move all of Europe toward species homogenization.—Isabelle Heilman
Certain groups of related species are more susceptible than others to harm by humans, raising the question of whether related species on the tree of life diagram will also be more susceptible to harm caused by climate change. Adaptability to change in climate differs among species; however, related species tend to have similar characteristics of adaptability. If related species are similarly vulnerable to the effects of climate change, the losses of related species would be more obvious in the tree of life diagram. To measure the effects of climate change on the tree of life of European species, Thullier et al. examined 1,280 plant, 340 bird, and 140 mammal species found across Europe. The researchers used species distribution models and climate prediction models to find that variances in suitable climate were alike in related species. Using the information from ranges in suitable climate as a stand-in for extinction risk, the researchers then saw that although there would be a decrease in diversity among related species, however, the calculated decrease was not greater than the decrease under a random extinction model. By mapping present and future species distribution, the authors found that the future spatial distribution of species in Europe will change, with Northern Europe increasing in diversity and Southern Europe decreasing in diversity.
To find the changes in suitable climate for the plant, bird, and mammal species, the researchers used several species distribution models, high resolution global climate models, and four emission scenarios in periods of 29 years from 1969 to 2080. Vulnerability of species to effects of climate change was found as a value between –100 and >100 calculated by the change in area with suitable climate for each species. This value, the change in suitable climate (CSC), was used to represent the probability of extinction and was compared with a random extinction model which was found by randomizing the probability of extinction and finding the new amount of species diversity. To measure the relatedness of plant and bird species, the authors ran searches at the family level on a compilation of smaller trees of life to find the highest likelihood tree. For the mammal trees, the researchers used 100 evolutionary trees based on the work of Fritz et al. (2009). To find the spatial distribution of the species, the authors estimated the area where the species where projected to exist by the amount pixels taken up on a map.
It was found that closely related species had similar suitable climate ranges, but some species’ suitable climate was reduced, while others increased. Birds in Tringa and Numenius species had decreased suitable climate ranges, while Ardeidae species increased. Plants were mostly found to contract their ranges. Mammals were found to be least vulnerable to harm as a result of climate change. Comparing the results of the constructed and random models showed that the predicted effects of climate change on species diversity did not vary greatly from randomized effects. The modeling showed that some areas of Europe will have positive changes in species diversity, while other areas will have negative ones. Southern Europe currently experiences high species diversity, however in the future it will experience low species diversity. Northern Europe currently has low species diversity, but in the future it will experience high species diversity.
Changes in climate across Europe are changing the amount of suitable climate habitats where plant, mammal, and bird species can live. According to this study, the overall amount of species diversity will not change dramatically, however the spatial distribution of species on the tree of life will. Spatial distribution of species across Europe will also change, with greater species diversity at the higher elevations and latitudes of Northern Europe. Measures to control the speed of global warming must be taken in an effort to allow these species to adapt and to avoid major damage to the tree of life diagram.
Other Works cited
Fritz, S., Bininda-Emonds, O., Purvis, A. Geographical variation in predictors of mammalian extinction risk: big is bad, but only in the tropics. Ecology Letters 6, 538–549 (2009)