Top-kill of vascular plants during a drought on granite bedrock glades in the Huron Mountains, Michigan

Document Type

Article

Publication Date

5-30-2024

Abstract

The impacts of drought have been less studied in terrestrial plant communities than other types of natural disturbance. Most drought studies have focused on regional impacts or used climate modeling over a broad geographic area. This study provides insight into the fine-scale impacts within a single natural community occupying a small area that is more susceptible to drought than its surroundings. This study was conducted on granite bedrock glades in the Huron Mountains in Michigan's Upper Peninsula. In May 2021, prior to drought conditions, 100-m-long transects were established; they were sampled with 1-m2 plots in September 2021 after an unusually dry spring and summer. Environmental variables were recorded at two scales (site and plot level), and cover values for alive and top-killed vegetation cover were given for each species. Among the 48 species in our study, 18 experienced at least some top-kill, and 26% of the total vegetation cover was top-killed in 2021. Nonmetric multidimensional scaling ordination was used to explain the variation in top-killed plant data among plots and species. A three-axis solution was reached in PC-ORD with a final stress of 7.55, and a total instability of 0.00 was achieved after 86 iterations. While the measured variables were not strongly correlated with the axes (r2 values < 0.07), the plots with the highest dead species cover were on south-facing slopes with no canopy cover. We hope this study can provide some insight into plant community response to drought at fine scales.

Publication Title

Journal of the Torrey Botanical Society

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