Detecting community changes in response to management practices using bryophyte herbarium specimens collected in the southern Appalachians

Aim : Monitoring plant communities in response to drivers of global change is essential for understanding ecosystem health and conservation over time. Natural history collections are underutilized, open-source data that can be leveraged to study how communities change over time. This informs how under surveyed organisms, like bryophytes, may be impacted by drivers of global change. Location : We used herbarium specimen data to examine bryophyte community change in the southern Appalachians before and after the arrival of the balsam wooly adelgid (BWA). Methods : We used herbarium collections to examine raw and rarefied alpha diversity, as well as rarefied dissimilarity, over time. We compared two timespans, pre-BWA invasion and initial canopy recovery from invasion, to determine if species were either lost from, persisted in, or were new to high elevation areas and if these species had any shared features. Results : We found that mountains with greater disturbance resulted in lower levels of rarefied richness and that more extreme management practices may drive greater changes to the bryophyte community. However, this result cannot be decoupled from the disturbance with our data. Finally, we found that generalists significantly persisted through time compared to expected and compared to specialist species. Main conclusions : This is a promising use of herbarium specimens as the results match those of field-based experiments. As such, herbarium collections may be used as a substitute for permanent plots for lands with limited resources or a lack of expertise to determine the impacts management practices or invasion events have on ecological communities.