TROPICAL LATITUDES CONTAIN LESS

SPECILIZATION OF MUTUALISMS

Group B18Jason Zichettella, Arian Mizani,

Jingyu Zhu

Background Tropical rain forests have been known to be

“earth’s most complex biome” in terms of species, which leads biologists to believe that specialization is more prominent in tropical rain forests than temperate rain forests (Woodward). Two types of species that are present in all environments are Generalist Species and Specialist species.

Background Difference between Generalist Species and

Specialist Species’: Generalist Species are species that can withstand

many types of environments, such as “broad niches” (Sacks, Bannasch, Chomel, and Ernest 1392).

Specialist Species are species that are limited to exclusively a particular environment, which are known as “narrow niches” (Sacks, Bannasch, Chomel, and Ernest 1392).

Background Studies have shown increasing biotic

specialization toward the tropical regions near the equator in the western hemisphere. However, there was no strong latitudinal trend in the eastern hemisphere, but rather up north in the temperate forests of Europe away from the equator. Because of these results, latitudinal trend of specialization is still questionable.

Data/Results

Global distribution of pollination (red) and seed dispersal (blue)

Data set of 282 networks in 80 regions

Data/Results

Specialization increases as absolute latitude increases

Data/Results

Specialization consistently decreased with increasing cumulative annual temperature

Data/Results

Specialization decreases as plant diversity increases

Data/Results Specialization of both pollination and seed

dispersal networks decreased significantly toward tropical latitudesThis contradicts the assumption that biotic

interactions are more specialized in species rich tropical communities.

Specialization decreases with increased temperature

Discussion• According to the figures of data results, specialization is

actually more prevalent in the nontropics where at higher latitudes, there is more pollination and seed dispersal networks.

• Specialization increased as climate change velocity increased even though specialization decreased with higher annual temperatures. Specialization also decreased with increasing plant diversity in both regional and local regions.

• Pollinator species had a higher survival rate in tropical communities over temperate communities most likely due to different use resource availability.

Conclusion Specialization of pollination and seed dispersal networks

decreases toward tropical latitudes with a decrease in plant diversity

Contemporary climate patterns and plant diversity are more associated with specialization of pollination and seed dispersal than past climate stabilities are. (Specialization decreases with increasing temperature.)

Proposing that higher resource diversity triggers a more generalized dieting range of consumer species, the role of guild stucture gradients may supplement the effect of plant diversity and climate gradients in specilaiztion gradients.

Take-Home MessageThe gradient of mutaulistic specialization in pollination and seed dispersal networks gives credit to the hypothesis that specialization decreases with latitudinal gradient.

Works CitedSacks, Benjamin N., Danika L. Bannasch, Brumo B. Chomel, and Holly

B. Ernest. “Coyotes Demonstrate How Habitat Specialization by Individuals of a Generalist Species Can Diversify Populations in a Heterogeneous Ecoregion.” Oxford Journals 25.7 (2008): 1384-394. Oxford Journals. Oxford University Press, 7 Apr. 2008. Web. 27 Sept. 2012.

Schleuning et al., Specialization of Mutualistic Interaction Networks Decreases toward Tropical Latitudes, Current Biology (2012), http://dx.doi.org/10.1016/j.cub.2012.08.015

Woodward, Susan L. "Tropical Rainforest." Biomes of the World. Department of Geospatial Science, Radford University, 1997. Web. 27 Sept. 2012. <https://php.radford.edu/~swoodwar/biomes/?page_id=100>.