Session Information
| Session | Poster Session | | Date | Monday (2008-04-07) | | Time | 5:00 PM - 7:00 PM | | Room | Grand Terrace |
Presentation Information
| Presenter | Stefanie Wacker | | Title | Understory vegetation response to timber harvest in the Black Hills, South Dakota, USA | | Affiliation | South Dakota State University | | Authors | Stefanie Wacker, Jack Butler, Michael Wimberly | | Keywords | Disturbance, Invasive species, Timber harvest | | Presentation Type | Poster | Abstract:
Invasive plant species are one of the most costly economical, environmental, and ecological threats to native, intact ecosystems. While a disturbance is not required, invasive plants often become established and expand in areas of disturbance, either natural or anthropogenic. In the Black Hills National Forest (BHNF) of western South Dakota and eastern Wyoming, extensive timber harvest has the potential of promoting an undesired influx of invasive plants. The 0.8 million hectare Black Hills are dominated by ponderosa pine (Pinus ponderosa) with various common understories of mixed grasses, bearberry (Arctostaphylos uva-ursi), coral berry (Symphoricarpos albus), and common juniper (Juniperus communis). To best combat invasive plants, a thorough understanding of the drivers of plant invasions following multi-scale disturbances is needed. The primary objective of this study is to evaluate the understory response to overstory removal by examining pre- and post-harvest species composition in relation to three timber harvest methods: 1) lop-and-scatter, where trees are hand-cut and leaving slash scattered over the entire site, 2) cut-to-length, where boles are mechanically cut to length and de-limbed and slash left scattered, and 3) whole tree, where boles are mechanically cut, skidded to a landing and de-limbed leaving slash in large piles. In 2007, 99 permanent plots were established within and outside of 5 timber sales prior to harvest, with additional timber sales to be added in subsequent field seasons throughout the spatial extent of the BHNF. Modified Whittaker plots were used to sample for species composition and foliar cover at multiple spatial scales, 1m2, 100m2, and 1000m2. Slope, aspect, topographic position, canopy closure, and total number of trees (over 0.3 m tall, DBH > 10 cm) were also recorded at each plot. We analyzed pre-treatment community composition data and identified several key environmental drivers of invasive species prevalence in undisturbed forests at the landscape level. This preliminary analysis will provide a baseline for interpreting the effects of disturbance on the composition, abundance, distribution, and persistence of invasive plants. Ultimately, the results of this research will assist land managers in developing adaptive management plans for invasive plants at a variety of spatial and temporal scales. |
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