Abundance and diversity of mushrooms in differently-aged forests of northern Michigan.

Abstract

The purpose of this study is to examine the relationship between forest age and the abundance and diversity of fungi within. To study this, we looked at four neighboring but distinct segments of forest which underwent controlled burns in 1936, 1954, 1980 and 1998, respectively. Within each plot we ran five transects approximately 75m long, and recorded the species and quantity of mushrooms within two meters of the transect on either side. We noted the greatest abundance of mushrooms in the 1954 plot, with 547 specimens, and the least mushrooms in the most recently burned 1998 plot – only 11 specimens. The number of species within the four plots ranged from eight to 22, with the greatest number in the 1936 plot. For each transect we calculated the Simpson Index and the Shannon Diversity Index. The Simpson Index showed the 1954 plot as the most diverse, while the Shannon Diversity Index showed the 1936 plot as the most diverse. However, a Tukey Test for both the Simpson Index and the Shannon Diversity Index comparing the four plots showed no statistically significant relationships. Observationally, though, there appears to be a trend in which the largest and most varied mushroom populations occurred in the 1954 plot – the second oldest plot. From this we propose that longer, more in-depth studies of forests undergoing controlled burns might show, to a statistically significant degree, the greatest fungi abundance and diversity in intermediately aged plots, in accordance with the Intermediate Disturbance Hypothesis.