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We analyzed the conservation status of 73 vegetation cover types distributed across a 1.76 million km2 region in 10 states of the western USA. We found that 25 vegetation cover types had at least 10% of their area in nature reserves. These were generally plant communities located at higher elevations and thus more commonly associated with national parks and wilderness areas. All but three of the remaining 48 cover types occurred with sufficient area on publically owned lands in the region to imply that transforming land management intent on these lands could also increase their protection. We also analyzed the level of protection afforded each cover type across its entire geographic distribution in the region. Most...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Biological Conservation,
Conservation planning,
Gap analysis,
Nature reserves,
Plant community
Arbuscular mycorrhizal fungi (AMF) are important root symbionts that can provide benefits to plant hosts, yet we understand little about how neighboring hosts in a plant community contribute to the composition of the AMF community. We hypothesized that the composition of the plant neighborhood, including the identities of both host and neighbor, would alter AMF community composition. We tested this in a glasshouse experiment in which a native perennial grass (Nassella pulchra) and three annual grasses (Avena barbata, Bromus hordeaceaous and Vulpia microstachys) were grown in two neighborhoods: conspecific monocultures and heterospecific perennial-annual mixtures. To identify AMF taxa colonizing plant roots, we used...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Avena barbata,
Bromus,
Nassella pulchra,
New Phytologist,
Vulpia microstachy,
Black greasewood (greasewood) and gray rabbitbrush are important shrub components of several plant communities throughout western North America. Land managers may view these species differently depending on their goals. Greasewood and gray rabbitbrush shrub communities may be invaded by several invasive plants including Russian knapweed, perennial pepperweed, hoary cress, halogeton, and several annual mustards. Metsulfuron and chlorsulfuron are commonly used for controlling these and other invasive plants, but little is known regarding their impacts on greasewood and gray rabbitbrush. Our objective was to quantify the impact of these herbicides on greasewood and gray rabbitbrush communities from both an efficacy...
The indirect effects of native generalist insect herbivores on interactions between exotic and native grassland plants have received limited attention. Crested wheatgrass (Agropyron cristatum) is the most common exotic rangeland grass in western North America. Crested wheatgrass communities are resistant to colonization by native plant species and have strong competitive effects on native species, imposing problems for the restoration of native grasslands. Grasshoppers are generalist herbivores that are often abundant in Crested wheatgrass?dominated sites in the northern Great Plains. We conducted two experiments in a Crested wheatgrass?dominated grassland in western North Dakota to test the hypothesis that grasshopper...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Restoration Ecology,
crested wheatgrass,
generalist herbivore,
grasshoppers,
indirect effects,
Large predators potentially can help shape the structure and functioning of terrestrial ecosystems, yet strong evidence of top-down herbivore limitation has not been widely reported in the scientific literature. Herein we synthesize outcomes of recent tri-trophic cascades studies involving the presence and absence of large predators for five national parks in the western United States, including Olympic, Yosemite, Yellowstone, Zion, and Wind Cave. Historical observations by park biologists regarding woody browse species and recently compiled age structure data for deciduous trees indicate major impacts to woody plant communities by ungulates following the extirpation or displacement of large predators. Declines...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Biological Conservation,
National parks,
Predators,
Response ratio,
Trophic cascades,
Using a retrospective study of tamarisk removal sites across five states in the southwestern United States, we investigated (1) decreases in tamarisk cover; (2) the effects of tamarisk removal on vegetation; and (3) whether cutting or burning tamarisk has differing effects on plant communities. Our study provides an important first step in recognizing the effects of removing a dominant invasive species on meeting long-term goals of riparian restoration. We found that (1) both cutting and burning reduced mean tamarisk foliar cover by 82?95%, and this reduction was sustained over time. (2) Native foliar cover was 2- to 3-fold higher on tamarisk removal sites, but total foliar cover remained 60?75% lower than on control...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Restoration Ecology,
Tamarix,
invasive plant management,
plant community,
riparian restoration,
After a long period in which fuel loads were sparse, fire recently has occurred with high frequency in the ungrazed riparian zone of the Upper San Pedro River in southern Arizona’s Chihuahuan Desert. We studied four accidental fires that occurred during 1994–2003 (two in different years at the same site). Woody vegetation was contrasted between three burned sites and matched spatial controls, and before and after the most recent fire. Herbaceous vegetation was sampled in multiple years producing a chronosequence of time since fire (from 4 months to 8 years). Riparian fire was associated with reductions in woody plant species diversity and canopy cover. In contrast, fire caused a short-term (2 year) pulse of...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Restoration Ecology,
disturbance,
diversity,
dryland,
fire,
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