Biotic cover in crescentic gouges of New England 2021

In this study, I tested the hypothesis that crescentic gouges –
conspicuous, crescent-shaped troughs on recently glaciated granite
domes – are important microsites of alpine and subalpine biomat
development and plant establishment, and thus can be used to augment
montane ecosystem conservation and restoration efforts. To test my
hypothesis, in September 2021, I quantified biotic percent cover in
crescentic gouges and measured gouge proximity to upslope,
established biomat and plant assemblages (i.e., presumed propagule
sources), proximity to established hiking trails (i.e., distance
from disturbance), and gouge sizes at four mid-elevation granite
balds in NH, VT, and ME, USA. I used distance-based linear
regression modeling (DISTLMv.5) to evaluate the effects of these
predictor variables on biotic cover in the gouges. At all sites, all
three predictor variables (proximity to upslope, well-developed
assemblage, proximity to hiking trail, and gouge size) together
explained a statistically significant proportion of the variation in
total biotic cover in crescentic gouges. At one site (Speckled
Mountain, ME), all three predictors explained 71% of the variation
in biotic cover; the proportion of variance explained at other sites
was lower but still statistically significant. When I evaluated the
effects of predictor variables individually, each significantly
affected biotic cover in crescentic gouges at all sites. My data
suggest that crescentic gouges, particularly larger gouges not
overlain by pine canopy, support strong biomat and plant
colonization, and thus should be considered in alpine and subalpine
plant conservation and restoration initiatives. Cordoning off
crescentic gouges at mid-elevation sites would be a novel,
inexpensive, and relatively straightforward way to augment existing
alpine and subalpine conservation and restoration efforts.