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Bryophytes disperse by small unicellular spores between 7 ?m und usually less than 100 ?m. A large percentage of species is sterile and propagates vegetatively either by special brood bodies or fragments of whole plants. It is shown that there is no difference in the effectiveness between generative and vegetative propagation. Size and weight of the diaspores suggest that both must easily be dispersed and the species must therefore have wide ranges. This does, however, not result in ubiquitous occurrence. This is only true for part of the species. Many, even sterile species show wide transcontinental ranges. On the other hand, there are many examples of limited to very limited distribution in spite of a rich production...
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Improved sampling designs are needed to detect, monitor, and predict plant migrations and plant diversity changes caused by climate change and other human activities. We propose a methodology based on multi-scale vegetation plots established across forest ecotones which provide baseline data on patterns of plant diversity, invasions of exotic plant species, and plant migrations at landscape scales in Rocky Mountain National Park, Colorado, USA. We established forty two 1000-m2 plots in relatively homogeneous forest types and the ecotones between them on 14 vegetation transects. We found that 64% of the variance in understory species distributions at landscape scales were described generally by gradients of elevation...
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We investigated butterfly responses to plot-level characteristics (plant species richness, vegetation height, and range in NDVI [normalized difference vegetation index]) and spatial heterogeneity in topography and landscape patterns (composition and configuration) at multiple spatial scales. Stratified random sampling was used to collect data on butterfly species richness from seventy-six 20 � 50 m plots. The plant species richness and average vegetation height data were collected from 76 modified-Whittaker plots overlaid on 76 butterfly plots. Spatial heterogeneity around sample plots was quantified by measuring topographic variables and landscape metrics at eight spatial extents (radii of 300, 600 to 2,400 m)....
Managers of natural landscapes need cost-efficient, accurate, and precise systems to inventory plant diversity. We investigated a nested-intensity sampling design to assess local and landscape-scale heterogeneity of plant species richness in aspen stands in southern Colorado, USA. The nested-intensity design used three vegetation sampling techniques: the Modified-Whittaker, a 1000-m2 multiple-scale plot (n 5 8); a 100-m2 multiple-scale Intensive plot (n 5 15); and a 100-m2 single-scale Extensive plot (n 5 28). The large Modified-Whittaker plot (1000 m2) recorded greater species richness per plot than the other two sampling techniques (P , 0.001), estimated cover of a greater number of species in 1-m2 subplots (P...
Wepresenttheresultsofarapidassessmentofbutterflydiversityinthe754haBeaverMeadows study area in Rocky Mountain National Park, Larimer County, Colorado. We measured butterfly species rich- ness and relative abundance as part of a landscape-scale investigation of diversity patterns involving sever- al groups of organisms. A stratified random sampling design was used to include replication in both rare and common vegetation types. We recorded 49 butterfly species from the twenty-four 0.1 ha plots that were sam- pled four times during June, July, and August 1996. Butterfly species richness, diversity, and uniqueness were highest in quaking aspen (Populus tremuloides Michaux) groves and wet meadows, which occupy only...


    map background search result map search result map Effects of spatial heterogeneity on butterfly species richness in Rocky Mountain National Park, CO, USA Monitoring shifts in plant diversity in response to climate change: a method for landscapes Effects of spatial heterogeneity on butterfly species richness in Rocky Mountain National Park, CO, USA Monitoring shifts in plant diversity in response to climate change: a method for landscapes