Filters: Types: Citation (X) > partyWithName: Stohlgren, Thomas J (X) > partyWithName: Chong, Geneva W (X)
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Some theories and experimental studies suggest that areas of low plant species richness may be invaded more easily than areas of high plant species richness. We gathered nested-scale vegetation data on plant species richness, foliar cover, and frequency from 200 1-m2 subplots (20 1000-m2 modified-Whittaker plots) in the Colorado Rockies (USA), and 160 1-m2 subplots (16 1000-m2 plots) in the Central Grasslands in Colorado, Wyoming, South Dakota, and Minnesota (USA) to test the generality of this paradigm. At the 1-m2 scale, the paradigm was supported in four prairie types in the Central Grasslands, where exotic species richness declined with increasing plant species richness and cover. At the 1-m2 scale, five forest...
Studies to identify gaps in the protection of habitat for species of concern have been inconclusive and ham- pered by single-scale or poor multi-scale sampling methods, large minimum mapping units (MMU?s of 2 ha to 100 ha), limited and subjectively selected field observations, and poor mathematical and ecological models. We overcome these obstacles with improved multi-scale sampling techniques, smaller MMU?s (< 0.02 ha), an unbiased sampling design based on double sampling, improved mathematical models including species-area curves corrected for habitat heterogeneity, and geographic information system-based ecological models. We apply this landscape analysis approach to address resource issues in Rocky Mountain...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Geographic Information System (GIS),
Landscape Ecology,
ecosystem models,
keystone ecosystems,
map accuracy assessment,
Only a small portion of any landscape can be sampled for vascular plant diversity because of constraints of cost (salaries, travel time between sites, etc.). Often, the investigator decides to reduce the cost of creating a vegetation map by increasing the minimum mapping unit (MMU), and/or by reducing the number of vegetation classes to be considered. Questions arise about what information is sacrificed when map resolution is decreased. We compared plant diversity patterns from vegetation maps made with 100-ha, 50-ha, 2-ha, and 0.02-ha MMUs in a 754-ha study area in Rocky Mountain National Park, Colorado, United States, using four 0.025-ha and 21 0.1-ha multiscale vegetation plots. We developed and tested species?log(area)...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Ecological Applications,
Jaccard?s coefficients,
Modified-Whittaker plots,
keystone ecosystems,
minimum mapping unit,
We present a rapid, cost-efficient methodology to link plant diversity surveys from plots to landscapes using: (1) unbiased site selection based on remotely sensed information; (2) multi-scale field techniques to assess plant diversity; (3)mathematical models (species-area curves) to estimate the number of species in larger areas corrected for within-type heterogeneity; and (4) mathematical techniques to estimate total species richness and patterns of plant diversity in a landscape. We demonstrate the methodology in a 754 ha study area in Rocky Mountain National Park, Colorado, U.S.A.,using four 0.025 ha and twenty-one 0.1 ha multi-scale vegetation plots. We recorded 330 plant species (~1/3 the number of plants...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Environmental Monitoring and Assessment,
Springer Netherlands,
botanical surveys,
keystone ecosystems,
species overlap,
We demonstrate new multi-phase, multi-scale approaches for sampling and modeling native and exotic plant species to predict the spread of invasive species and aid in control efforts. Our test site is a 54,000-ha portion of Rocky Mountain National Park, Colorado, USA. This work is based on previous research wherein we developed vegetation sampling techniques to identify hot spots of diversity, important rare habitats, and locations of invasive plant species. Here we demonstrate statistical modeling tools to rapidly assess current patterns of native and exotic plant species to determine which habitats are most vulnerable to invasion by exotic species. We use stepwise multiple regression and modified residual kriging...
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