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Beavers (Castor canadensis Kuhl) can influence the competitive dynamics of plant species through selective foraging, collection of materials for dam creation, and alteration of hydrologic conditions. In the Grand Canyon National Park, the native Salix gooddingii C.R.Ball (Goodding?s willow) and Salix exigua Nutt. (coyote willow) are a staple food of beavers. Because Salix competes with the invasive Tamarix ramosissima Ledeb., land mangers are concerned that beavers may cause an increase in Tamarix through selective foraging of Salix. A spatial analysis was conducted to assess whether the presence of beavers correlates with the relative abundance of Salix and Tamarix. These methods were designed to detect a system-wide...
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Land management practices often directly alter vegetation structure and composition, but the degree to which ecological processes such as herbivory interact with management to influence biodiversity is less well understood. We hypothesized that intensive forest management and large herbivores have compounding effects on early-seral plant communities and plantation establishment (i.e., tree survival and growth), and the degree of such effects is dependent on the intensity of management practices. We established 225 m2 wild ungulate (deer and elk) exclosures nested within a manipulated gradient of management intensity (no-spray Control, Light herbicide, Moderate herbicide and Intensive herbicide treatments), replicated...
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A dataset of caterpillar performance in an experiment manipulating mean and variance of xanthotoxin levels in diet. Caterpillar growth, development time, and egg production of mated females is presented. Data were collected by all authors in 2017 in a laboratory at Colorado State University, Fort Collins, CO.
Pathogens and herbivores can severely reduce host fitness, potentially leading to altered succession rates and changes in plant community composition. Thus, to predict vegetation dynamics under climate change, it is necessary to understand how plant pathogens and herbivores will respond. Pathogens and herbivores are predicted to increase under climate warming because the amount of time available for growth and reproduction will increase. To test this prediction, we used a warming experiment in which heaters were suspended over a natural montane meadow for 12 years. In the summer of 2002, we quantified damage by all the observable (aboveground) pathogens and herbivores on six of the most common plant species (Artemisia...
This study examined whether an individual plant's risk of herbivory was affected by its nearest neighbor. Individually potted tillers of Bouteloua gracilis were placed in a natural habitat with one of two neighbors (B. gracilis conspecifics or Aristida spp.), and in one of two cover treatments (high: in center of neighbor canopy, and low: at periphery of canopy). After one month, the experimental tillers were collected and scored for herbivory. We found that the less palatable neighbor, Aristida spp., reduced the probability that herbivores would feed upon experimental tillers in one of the two years of our study, but in both years increased the amount of feeding on those tillers that were attacked. The amount of...
Presented by Don Spalinger & Nathan WolfThis seminar focuses on our concepts of regulation of nutrient flows through tundra ecosystems and the effect that climate (or weather) has on these processes. Nutrient flow and climate, in turn, should regulate plant phenology and production, and thus caribou behavior and nutrition. We will present some ideas for assessing the landscape patterns of these processes and monitoring their impacts. Finally, we will provide examples of such assessment and monitoring processes from our work in Western Alaska over the past two years.​
Categories: Data; Tags: ALPINE/TUNDRA, ALPINE/TUNDRA, CARBON, CARBON, CARBON CYCLE/CARBON BUDGET MODELS, All tags...
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Data on intraguild predation of arthropods on the tarweed Hemizonia congesta. Arthropod counts (predators, herbivores, etc) and counts of entrapped arthropod corpses on focal plants in an experiment manipulating arthropod carrion amount and plant damage. Quantifications of plant damage and reproduction are presented.
I investigated the individual and joint effects of simulated herbivory and interspecific competition on survival of Coleogyne ramosissima Torr. (blackbrush) seedlings. Seeds of C. ramosissima and Bromus rubens L. (red brome grass) were collected at mid-elevations (1220 to 1770 m) of the Spring Mountains in southern Nevada. A pot trial experiment was conducted for six months (27 wk) in a controlled environmental greenhouse. This trial experiment, consisting of a 2 � 2 factorial design with simulated rodent herbivory and interspecific competition with B. rubens as the main effects, resulted in four treatments. Herbivory on C. ramosissima by heteromyid and non-heteromyid species of rodents was simulated by clipping...
The tundra biome is the dominant terrestrial ecosystem of the circumpolar north, and its fate in a rapidly changing climate is of high scientific and socioeconomic concern. One of those concerns is that the majority of caribou herds throughout the circumpolar north are declining, perhaps as a result of climate change. The principal objective of this research is to reveal the connections between soil nutrient cycling, forage quality and caribou habitat selection. This framework is underpinned by the concept that tundra ecosystem productivity is ultimately driven by the thermodynamics of the system induced by climate.
Categories: Data, Publication; Types: Citation; Tags: ALPINE/TUNDRA, ALPINE/TUNDRA, CARBON, CARBON, CARBON CYCLE/CARBON BUDGET MODELS, All tags...
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Land management practices often directly alter vegetation structure and composition, but the degree to which ecological processes such as herbivory interact with management to influence biodiversity is less well understood. We hypothesized that intensive forest management and large herbivores have compounding effects on early-seral plant communities and plantation establishment (i.e., tree survival and growth), and the degree of such effects is dependent on the intensity of management practices. We established 225 m2 wild ungulate (deer and elk) exclosures nested within a manipulated gradient of management intensity (no-spray Control, Light herbicide, Moderate herbicide and Intensive herbicide treatments), replicated...
In southeastern Utah, Bromus tectorum occurs where Hilaria jamesii is dominant and rarely where Stipa hymenoides/S. comata dominate. To determine whether this distribution is due to soil characteristics or microhabitat, we transplanted H. jamesii soil to a Stipa site and vice versa during a severe drought (2001) and a wetter year (2002). Additionally, we planted B. tectorum under H. jamesii and Stipa canopies, with or without H. jamesii litter, and with or without herbivory. Bromus tectorum emergence and biomass in reciprocal transplants were similar at both sites; there were no site differences for all microhabitat treatments. Being under a plant canopy increased emergence in 2001 and decreased survival during...
The effect of herbivory on grassland whole-plant production is poorly understood. Herbivores can increase grassland aboveground productivity, and laboratory experiments suggest that herbivory should reduce grass root growth. However, few field studies have directly measured the response of grassland root production to herbivores. We examined the effect of native migratory ungulates on grassland primary production by comparing aboveground (NAP) and belowground (NBP) production in grazed vs. ungrazed (fenced) grassland at nine variable sites in Yellowstone National Park. NBP was determined with minirhizotrons to account for root turnover. Grazers stimulated aboveground, below-ground, and whole-grassland productivity...
We investigated the influence of long-term (56 years) grazing on organic and inorganic carbon (C) and nitrogen (N) contents of the plant-soil system (to 90 cm depth) in shortgrass steppe of northeastern Colorado. Grazing treatments included continuous season-long (May-October) grazing by yearling heifers at heavy (60-75% utilization) and light (20-35% utilization) stocking rates, and nongrazed exclosures. The heavy stocking rate resulted in a plant community that was dominated (75% of biomass production) by the C4 grass blue grama (Bouteloua gracilis), whereas excluding livestock grazing increased the production of C3 grasses and prickly pear cactus (Opuntia polycantha). Soil organic C (SOC) and organic N were not...
Invasion of natural ecosystems by exotic plant species is a major threat to biodiversity. Disturbance to native plant communities, whether natural or management induced, is a primary factor contributing to successful invasion by exotic plant species. Herbivory by both wild and domestic ungulates exerts considerable impact on structure and composition of native plant communities. Intensive herbivory by ungulates can enhance exotic plant invasion, establishment, and spread for three reasons: (1) many exotic plants are adapted to ground disturbances such as those caused by ungulate feeding, trampling, and movements; (2) many exotic plants are adapted for easy transport from one area to another by ungulates via endozoochory...
We compared beaver (Castor canadensis) foraging patterns on Fremont cottonwood (Populus deltoides subsp. wislizenii) saplings and the probability of saplings being cut on a 10 km reach of the flow-regulated Green River and a 8.6 km reach of the free-flowing Yampa River in northwestern Colorado. We measured the abundance and density of cottonwood on each reach and followed the fates of individually marked saplings in three patches of cottonwood on the Yampa River and two patches on the Green River. Two natural floods on the Yampa River and one controlled flood on the Green River between May 1998 and November 1999 allowed us to assess the effect of flooding on beaver herbivory. Independent of beaver herbivory, flow...
Although the variation in natural 15N abundance in plants and soils is well characterized, mechanisms controlling N isotopic composition of organic matter are still poorly understood. The primary goal of this study was to examine the role of NH3 volatilization from ungulate urine patches in determining 15N abundance in grassland plants and soil in Yellowstone National Park. We additionally used isotopic measurements to explore the pathways that plants in urine patches take up N. Plant, soil, and volatilized NH3d15N were measured on grassland plots for 10 days following the addition of simulated urine. Simulated urine increased 15N of roots and soil and reduced 15N of shoots. Soil enrichment was due to the volatilization...
Abstarct (from Oikos): Urban landscapes are characterized by high proportions of impervious surface resulting in higher temperatures than adjacent natural landscapes. In some cities, like those at cooler latitudes, trees may benefit from warmer urban temperatures, but trees in many cities are beset with problems like drought stress and increased herbivory. What drives patterns of urban tree health across urbanization and latitudinal temperature gradients? In natural systems, latitude–herbivory relationships are well‐studied, and recent temperate studies have shown that herbivory generally increases with decreasing latitudes (warmer temperatures). However, the applicability of this latitude–herbivory theory in already‐warmed...
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Land management practices often directly alter vegetation structure and composition, but the degree to which ecological processes such as herbivory interact with management to influence biodiversity is less well understood. We hypothesized that intensive forest management and large herbivores have compounding effects on early-seral plant communities and plantation establishment (i.e., tree survival and growth), and the degree of such effects is dependent on the intensity of management practices. We established 225 m2 wild ungulate (deer and elk) exclosures nested within a manipulated gradient of management intensity (no-spray Control, Light herbicide, Moderate herbicide and Intensive herbicide treatments), replicated...
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A pollen addition experiment was conducted on the leaves of Croton setiger, a Californian forb. Pollen was added to leaves of randomly selected plants, and control plants had no pollen added. Over 2013 and 2014 the number of predatory and herbivorous insects were counted on each plant, and the number of damaged leaves and plant size were measured.
The resilience of willow (Salix monticola Bebb, Salix geyeriana Anderss., Salix planifolia Pursh) stems released from intense elk (Cervus elaphus) browsing in Rocky Mountain National Park, Colorado, was quantified in 1998 with a retrospective study that compared biomass, number, and length of segments on willow stems located inside (protected) and outside (browsed) elk exclosures. Segment biomass increased each year after protection by about 3?12 g year?1 on browsed stems and 10?27 g year?1 on protected stems. The number of segments on stems was similar for browsed and protected stems in the first 2 years after exclusion but differed in the next 3 years, when they increased exponentially on protected stems. Nearly...
map background search result map search result map Forest management and cervid herbivory data from Western Oregon, USA, 2012 Forest management and cervid herbivory data from Western Oregon, USA, 2012 (Camera Data) Forest management and cervid herbivory data from Western Oregon, USA, 2012 (Community Data) Laboratory Data on Cabbage Looper Moth Response to Xanthotoxin, 2018 Intraguild predation dataset for arthropods on tarweed plants Croton setiger predators, herbivores, and damage collected in California 2013-2014 Croton setiger predators, herbivores, and damage collected in California 2013-2014 Forest management and cervid herbivory data from Western Oregon, USA, 2012 Forest management and cervid herbivory data from Western Oregon, USA, 2012 (Camera Data) Forest management and cervid herbivory data from Western Oregon, USA, 2012 (Community Data) Laboratory Data on Cabbage Looper Moth Response to Xanthotoxin, 2018 Intraguild predation dataset for arthropods on tarweed plants