Herbivores Can Offset Loss of Plant Biodiversity in Grassland

Source: University of Minnesota 
Date: 3/9/14
http://phys.org/news/2014-03-herbivores-offset-loss-biodiversity-grassland.html


Summary: 
Two impacts often controlled by humans—being fertilized and being eaten—can combine to benefit biodiversity, according to researchers Elizabeth Borer and Eric Seabloom.

Scientists at 40 sites set up research plots with and without added fertilizer and with and without fences (to keep out herbivores). Following that, every year they measured plant growth, the amount of light reaching the ground, and number of species of plants growing in the plots.

The researchers found that fertilizing reduced the number of plant species in the plots, because species less able to tolerate a lack of light were covered by other, faster-growing plants. Additionally, the removal of vegetation by herbivores increased the amount of light that reached the ground, and thus plant species diversity increased. 

Relevance:

This article relates to many units, including ecosystems, evolution, and plants. As Global Warming poses an increasingly devastating threat to ecosystems, it is important to learn what conditions we as humans can control that will help them survive. It relates to evolution because it shows that the plants that grew faster were able to retain more light, and therefore had a better chance of surviving and reproducing, illustrating natural selection. It relates to the plants unit because it deals with the conditions that influence plant growth. Overall, it is important because humans are changing both herbivore distribution and the supply of nutrients like nitrogen or phosphorus. Understanding the connection between nutrients, herbivores and plant growth is critical to feeding a growing worldwide human population and to protecting threatened species and ecosystems.