Ecosystem dynamics in Central Appalachian riparian forests affected by hemlock woolly adelgid
| Main Author: | |
|---|---|
| Language: | English |
| Published: |
The Ohio State University / OhioLINK
2012
|
| Subjects: | |
| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1337364581 |
| id |
ndltd-OhioLink-oai-etd.ohiolink.edu-osu1337364581 |
|---|---|
| record_format |
oai_dc |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Ecology Environmental Science Forestry Eastern hemlock Tsuga canadensis Hemlock woolly adelgid Adelges tsugae foundation species ecological resilience alternate state dynamics central Appalachians unglaciated Allegheny Plateau Central Hardwood Forest |
| spellingShingle |
Ecology Environmental Science Forestry Eastern hemlock Tsuga canadensis Hemlock woolly adelgid Adelges tsugae foundation species ecological resilience alternate state dynamics central Appalachians unglaciated Allegheny Plateau Central Hardwood Forest Martin, Katherine L. Ecosystem dynamics in Central Appalachian riparian forests affected by hemlock woolly adelgid |
| author |
Martin, Katherine L. |
| author_facet |
Martin, Katherine L. |
| author_sort |
Martin, Katherine L. |
| title |
Ecosystem dynamics in Central Appalachian riparian forests affected by hemlock woolly adelgid |
| title_short |
Ecosystem dynamics in Central Appalachian riparian forests affected by hemlock woolly adelgid |
| title_full |
Ecosystem dynamics in Central Appalachian riparian forests affected by hemlock woolly adelgid |
| title_fullStr |
Ecosystem dynamics in Central Appalachian riparian forests affected by hemlock woolly adelgid |
| title_full_unstemmed |
Ecosystem dynamics in Central Appalachian riparian forests affected by hemlock woolly adelgid |
| title_sort |
ecosystem dynamics in central appalachian riparian forests affected by hemlock woolly adelgid |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2012 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1337364581 |
| work_keys_str_mv |
AT martinkatherinel ecosystemdynamicsincentralappalachianriparianforestsaffectedbyhemlockwoollyadelgid |
| _version_ |
1719430608214556672 |
| spelling |
ndltd-OhioLink-oai-etd.ohiolink.edu-osu13373645812021-08-03T06:05:02Z Ecosystem dynamics in Central Appalachian riparian forests affected by hemlock woolly adelgid Martin, Katherine L. Ecology Environmental Science Forestry Eastern hemlock Tsuga canadensis Hemlock woolly adelgid Adelges tsugae foundation species ecological resilience alternate state dynamics central Appalachians unglaciated Allegheny Plateau Central Hardwood Forest In an era of rapid ecological change due to loss of biodiversity, climate change, and altered nutrient dynamics, predicting ecosystem dynamics and maintaining ecosystem services provided by complex natural ecosystems is an increasing concern. Novel disturbances, including those caused by invasive insects, provide an unfortunate opportunity to test the applicability of ecological theories to practical problems. One such case study is the loss of eastern hemlock (Tsuga canadensis, hemlock) from much of eastern North America due to the invasive pest hemlock woolly adelgid (Adelges tsugae; HWA). Foundation species such as hemlock are abundant and define the ecosystem processes of a community through a small number of strong interactions. As these interactions are lost, ecosystems are predicted to transition rapidly and develop distinctly different energy exchanges, nutrient cycles, and compositions that define a new community state. Much of the understanding of such transitions is conceptual. To advance the understanding of the function of foundation species and transitions to alternate community states when a foundation species is lost, my dissertation examines vegetation community composition and ecosystem function in 38 hemlock-dominated riparian forests across the central Appalachians. On the unglaciated Allegheny Plateau in Ohio, uninvaded forests provide baseline data on hemlock as a foundation species. Across West Virginia and Virginia, sites impacted by HWA for 9-32 years were selected as a chronosequence to compare changes in compostion and function. Hemlock forests exhibit low species richness, and thus have low resiliency. In uninvaded forests of Ohio, hemlock dominates the vegetation, although other species are structured by environmental gradients. Structural equation modeling indicates hemlock has a negative influence on vegetation species richness, light availability and productivity. Thus, a likely future HWA arrival will result in a complete reorganization of these ecosystems, but impacts will differ across environmental gradients. Data from sites impacted by HWA 9-32 years in West Virginia and Virginia indicate all hemlock forests will likely be impacted. Although mortality is initially slowed at higher elevations and on steeper slopes with northerly aspects, eventually, the duration of HWA invasion is the most important driver of mortality and ecosystem change. As decline progress, hemlock remains dominant in sites impacted for decades, although compositions are shifting and diverging across overstory hemlock decline classes. Some species, including the native evergreen shrub rhododendron (Rhododendron maximum) and other evergreen species including red spruce (Picea rubens), may be particularly influential during community reorganization. Environmental gradients, including elevation and soil characteristics, are also important ecologial drivers. Among overstory hemlock decline categories, resource availability and nutrient cycling are accelerating, but this varies with environmental context. This research supports broad patterns in compositional and functional shifts found in other regions, but also highlights the complexity of the loss of hemlock as a foundation species. As a model system, hemlock provides and example where resilience and atlternate state theories apply, but require some expansion for complex systems dominated by long-lived species. This indicates restoration and management will be more efficient when adapted based on the environmental context and component species. 2012-06-22 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1337364581 http://rave.ohiolink.edu/etdc/view?acc_num=osu1337364581 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |