The changeover of the grasslands into forest ecosystem has become an ever growing problem in the US.The expansion of trees is being viewed as a threat for the tall grass prairies and researchers are trying to thrash out a way to slow down the takeover.
Kansas State University reported that researchers have determined burn intervals can predict how quickly woody vegetation will expand along streams.
Walter Dodds, university distinguished professor of biology said, “This is an important issue regionally, because as trees expand into these grassland areas, people who are using grassland for cattle production have less grass for animals, too.”
The details of the findings can be found in the recent edition of journal PLOS ONE
The study involves analysis of 25 years of aerial photography in the Konza Prairie Biological Station. The focus of the scientists were on three factors
- Burn intervals
- Grazers, such as bison
- Historical presence of woody vegetation
The analysis showed that burn intervals predicted the rate of woody vegetation expansion in these regions. In other words, burning can help to halt tree takeover of grass land prairies.
Dodds said “It’s clear from this research that if you don’t burn at all, these grassland streams basically are going to switch to forests and will not be grassland streams anymore.”
Bison do not assist to decrease trees and shrub expansion along the streams because they hardly spend much time near the water.
A hypothesis suggests that increased carbon dioxide could be helping the woody vegetations into the grasslands. Grasses are normally better at conserving water and make use of the carbon dioxide. However as the atmospheric carbon dioxide increases trees have an easier time growing.
Veach, doctoral student in biology said, “The tall grass prairie is almost nonexistent on the globe. In order for us to preserve tall grass prairie, we need to look at woody encroachment because it has been an issue. Things like no fire or differences in climate change may allow woody plant species to competitively take over grasslands.”