scholarly journals Responses of Nematodes to Ungulate Herbivory on Bluebunch Wheatgrass and Idaho Fescue in Yellowstone National Park

1994 ◽  
Vol 18 ◽  
pp. 126-130
Author(s):  
Evelyn Merrill ◽  
Jon Hak ◽  
Nancy Stanton
Keyword(s):  
Root Growth ◽  
Yellowstone National Park ◽  
Root Biomass ◽  
National Park ◽  
Growing Season ◽  
Belowground Biomass ◽  
Winter Range ◽  
Bluebunch Wheatgrass ◽  
Festuca Idahoensis ◽  
Agropyron Spicatum

Above- and belowground biomass of Idaho fescue Festuca idahoensis and bluebunch wheatgrass Agropyron spicatum and nematode densities under these plant species were sampled during the growing season inside and outside a 2-year old exclosure on Crystal Bench in Yellowstone National Park. Early in the growing season, grazed plants of both species had lower shoot and root biomass than ungrazed plants. Standing biomass of grazed plants was equal to ungrazed plants at the end of the growing season. Densities/g root biomass of phytophagous and bacterial feeding nematodes were higher under grazed than ungrazed plants of both plant species only early in the growing season. Foliar concentrations of nitrogen in grazed plants were higher than ungrazed plants but there was no difference in root nitrogen between grazed and ungrazed plants. The effects of ungulate grazing on the Northern winter range of Yellowstone National Park has recently received considerable attention (Frank 1990, Coughenour 1991, Singer 1992, Wallace submitted). Early interest in this topic centered around the question to cull or not to cull elk in the Park. However, as the concepts of "maintaining ecological processes" (Houston 1982) and "ecosystem management" (Keiter 1991) have gained acceptance in Park management, understanding the dynamics and interactions of a broader array of herbivores inhabiting the Park have become increasingly important. In this paper, we describe the results of a study which focused on the effects of aboveground herbivory on nematode density and trophic structure. Root-feeding nematodes are major herbivores in other grassland systems and may consume twice as much biomass as aboveground consumers (Ingham and Detling 1984, Stanton 1988). Houston (1982) reported that nothing is known about the effects of nematodes on the native grasses of the northern range especially in combination with aboveground grazers. We hypothesized that if spring grazing is intense, grazed plants would initially show a decline in root growth and phytophagous nematodes. Cessation of root growth is a common response of plants to grazing and may occur within the first 2-24 hours (Hodgkinson and Baas Becking 1977). Evidence to date supports the idea that phytophagous nematode densities are highest under moderate levels of grazing and low under heavily grazed and ungrazed plants (Stanton 1983, Stanton et al. 1984, Seastedt 1985, Seastedt et al. 1988). Because senescing roots, subsequent to grazing, provide increased substrates for decomposers, we also hypothesized that microbial activity and nitrogen mineralization should increase (Stanton et al. 1984). As a result, we expected to detect an increase in microbial feeding nematodes. As root regrowth occurred, we expected phytophagous nematodes to increase. However, we predicted that populations would not reach levels found under ungrazed plants because plants in grazed areas experience higher levels of nitrogen mineralization (Holland and Detling 1990) than ungrazed plants and may produce proportionally fewer numbers of root hairs (nutrient absorption organs) which serve as feeding sites for nematodes. Because of reduced densities of phytophagous nematodes and increased mineralization rates under grazed plants, we expected grazed plants to recoup their losses rapidly. The net result we predicted would be no detectable differences in aboveground or belowground biomass during years of normal rainfall. Thus, our study addressed 3 null hypotheses. First, root and shoot biomass of grazed and ungrazed plants will be similar at the end of the growing season. Second, density of phytophagous and microbial feeding nematodes will not differ between grazed and ungrazed plants. Finally, nitrogen concentration of roots and aboveground foliage will not be higher in grazed than in ungrazed plants. We focused our attention on bluebunch wheatgrass Agropyron spicatum and Idaho fescue Festuca idahoensis because of their importance as winter range forages and because Mueggler (1975) reported that bluebunch wheatgrass was more sensitive and recovered more slowly to heavy clipping than Idaho fescue.

scholarly journals Responses of Nematodes to Ungulate Herbivory on Bluebunch Wheatgrass and Idaho Fescue in Yellowstone National Park

1991 ◽  
Vol 15 ◽  
pp. 231-234
Author(s):  
Evelyn Merrill ◽  
Nancy Stanton
Keyword(s):  
Yellowstone National Park ◽  
National Park ◽  
Ecological Processes ◽  
Winter Range ◽  
Ungulate Herbivory ◽  
Bluebunch Wheatgrass ◽  
Ungulate Grazing ◽  
Northern Winter ◽  
Festuca Idahoensis ◽  
Agropyron Spicatum

The effects of ungulate grazing on the Northern winter range of Yellowstone National Park has recently received considerable attention. Early interest in this topic centered around the question to cull or not to cull elk in the Park. However, as the concepts of "maintaining ecological processes" (Houston 1982) and "ecosystem management" (Keiter 1991) have gained acceptance in Park management, understanding the dynamics and interactions of a broader array of herbivores inhabiting the Park will become increasingly important. In 1990, we studied the responses of Idaho fescue (Festuca idahoensis) and bluebunch wheatgrass (Agropyron spicatum) and their associated nematode communities to ungulate herbivory.

scholarly journals Belowground biomass and its annual increment in a montane beech forest in Mavrovo National Park, north-west Macedonia

2012 ◽  
Vol 58 (No. 4) ◽  
pp. 152-164
Author(s):  
S. Hristovski ◽  
L. Melovski ◽  
M. Šušlevska ◽  
L. Grupče
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
National Park ◽  
European Beech ◽  
Belowground Biomass ◽  
Beech Forest ◽  
Volume Index ◽  
Annual Increment ◽  
North West ◽  
Trees And Shrubs

The aim of this paper is to present the results of the investigation on belowground biomass and its annual increment in a beech ecosystem (Calamintho grandiflorae-Fagetum) in Mavrovo National Park, Republic of Macedonia. Belowground biomass was estimated in three layers of the ecosystem (tree, shrub and herb layers) for seven years during the period 1997–2005. Allometric regressions were established for the relationship of root biomass from volume index (D<sup>2</sup>H, diameter squared × height) on a sample of 10 model trees and 13 model shrubs of European beech (Fagus sylvatica L.). Fine root biomass of trees and shrubs was estimated in soil samples to a depth of 145 cm and divided into live and dead fine roots and subdivided into thickness classes. Belowground biomass of the herb layer was assessed in 20 herb species. It was estimated that the total belowground biomass in the ecosystem was 57.75 ·ha<sup>–1</sup>. The contribution of shrub and herb layers was insignificant (less than 0.2%). Biomass of the live fine roots was 10.16 t·ha<sup>–1</sup>, i.e. 18% of the total belowground biomass. Annual increment of trees and shrubs was 1.03 t·ha<sup>–1</sup>·y<sup>–1</sup> and 4.6 kg·ha<sup>–1</sup>·y<sup>–1</sup>, respectively.    

scholarly journals Landscape-Level Interactions Among Ungulates, Vegetation, and Large-Scale Fires in Northern Yellowstone National Park

1991 ◽  
Vol 15 ◽  
pp. 263-275
Author(s):  
Monica Turner ◽  
Yegang Wu ◽  
William Romme ◽  
Linda Wallace
Keyword(s):  
Spatial Pattern ◽  
Cervus Elaphus ◽  
Resource Use ◽  
Yellowstone National Park ◽  
National Park ◽  
Large Scale ◽  
Field Studies ◽  
Bison Bison ◽  
Fire Size ◽  
Winter Range

The scale of the 1988 fires in Yellowstone National Park (YNP) raised numerous questions for the management of natural areas subject to large, infrequent disturbances. An important management issue in YNP involves the interaction of large-scale fire with the large assemblage of native ungulates and vegetation dynamics in the landscape. In this 2-year research project, we are using landscape modeling and field studies to address basic questions about the effects of fire scale and heterogeneity on (1) resource utilization and survival of free-ranging elk (Cervus elaphus) and bison (Bison bison) and (2) the production and regeneration of preferred forage grasses and aspen in northern YNP. We are testing a series of eight hypotheses within the framework of two basic questions. First, we ask whether there are thresholds in fire size that interact with winter severity and ungulate density to determine ungulate resource use and survival on the winter range in northern YNP. This question focuses on the effects of fire size, regardless of the spatial pattern of burning. Second we ask, if large fires occur, does the spatial distribution of burned areas (and hence of higher quality forage) influence ungulate resource use during winters subsequent to the first post-fire year. In this question, we are addressing the effects of spatial pattern on herbivory. We focus on elk and bison because these are by far the most numerous ungulates in the area (Houston 1982), and we have chosen to examine winter grazing and browsing for several reasons. Winter range conditions are the primary determinant of ungulate survival and reproduction in Yellowstone, and winter utilization of the vegetation by ungulates appears to be intense in some areas. Ungulates make distinct foraging choices in the winter as in the rest of the year, and burn patterns may influence those choices in ways that we represent as hypotheses described later. In addition, the activities of animals can be readily monitored in the winter, and the exact locations of feeding and bedding sites can be determined. Travel routes are easily monitored, and the ability to sight animals is high; therefore, group locations and sizes can be readily determined. This research complements ongoing studies in YNP by expanding the spatial scale at which plant-herbivore dynamics are considered and by explicitly addressing the effects of spatial heterogeneity. Our research will produce a spatially explicit simulation model of the 78,000 ha winter range that predicts plant and ungulate dynamics under varying fire sizes, fire patterns, winter weather scenarios, and ungulate densities. The model and field studies will allow quantitative comparisons of the effects of large and small fires on ungulate survival and will thereby permit the simulation of the effects of alternative fire management scenarios.

scholarly journals Riparian Vegetation of the Northern Range, Yellowstone National Park; Classification, Succession, and Environmental Relationships

1985 ◽  
Vol 9 ◽  
pp. 148-152
Author(s):  
Robert Pfister ◽  
Stephen Cooper
Keyword(s):  
Yellowstone National Park ◽  
Riparian Vegetation ◽  
National Park ◽  
Gradient Analysis ◽  
Primary Objective ◽  
Community Type ◽  
Winter Range ◽  
Field Season ◽  
Vegetation Samples ◽  
Type Classification

The primary objective of the 1985 field season was to acquire a sufficient number of wetland vegetation samples (plots) from across the range of environments present on the northern range (elk winter range) of Yellowstone National Park (YNP) to permit community and gradient analysis of these wetlands. These plots will contribute toward our first product, a wetlands community type classification suitable for management applications such as vegetation mapping and interpretation.

scholarly journals Landscape-Level Interactions Among Ungulates, Vegetation, and Large-Scale Fires in Northern Yellowstone National Park

1992 ◽  
Vol 16 ◽  
pp. 206-211
Author(s):  
Monica Turner ◽  
Yegang Wu ◽  
Scott Pearson ◽  
William Romme ◽  
Linda Wallace
Keyword(s):  
Populus Tremuloides ◽  
Cervus Elaphus ◽  
Yellowstone National Park ◽  
National Park ◽  
Large Scale ◽  
Field Studies ◽  
Bison Bison ◽  
Fire Size ◽  
Management Scenarios ◽  
Winter Range

The scale of the 1988 fires in Yellowstone National Park (YNP) raised numerous questions for the management of natural areas subject to large, infrequent disturbances. An important management issue in YNP involves the interaction of large-scale fire with the large assemblage of native ungulates and vegetation dynamics in the landscape. We used landscape modeling and field studies to address basic questions about the effects of fire scale and heterogeneity on resource utilization and survival of free-ranging elk (Cervus elaphus) and bison (Bison bison), and the production and regeneration of preferred forage grasses and aspen in northern Yellowstone Park. More specifically, we asked (1) how fire size interacts with winter severity to control ungulate feeding behavior and survival, both in the initial postfire winter, when fire reduces forage, and in later postfire winters, when fire augments forage; (2) how fire pattern (e.g., clumped vs. dispersed burn sites) modifies the effects of fire size; (3) which environmental factors, including fire, influence selection of feeding areas by wintering ungulates at a variety of scales, from a single feeding station to the entire northern winter range; and (4) how the size and spatial pattern of burning influence regeneration of aspen (Populus tremuloides), a preferred and heavily browsed species in YNP. We focus on elk and bison because these are by far the most numerous ungulates in the area (Houston 1982), and we have chosen to examine winter grazing and browsing for several reasons. Winter range conditions are the primary determinant of ungulate survival and reproduction in Yellowstone, and winter utilization of the vegetation by ungulates appears to be intense in some areas. Ungulates make distinct foraging choices in the winter as in the rest of the year, and burn patterns may influence those choices in ways that we represent as hypotheses described later. In addition, the activities of animals can be readily monitored in the winter, and the exact locations of feeding and bedding sites can be determined. Travel routes are easily monitored, and the ability to sight animals is high; therefore, group locations and sizes can be readily determined. This research complements ongoing studies in Yellowstone by expanding the spatial scale at which plant-herbivore dynamics are considered and by explicitly addressing the effects of spatial heterogeneity. We produced a spatially explicit simulation model of the winter range that predicts plant and ungulate dynamics under varying fire sizes, fire patterns, winter weather scenarios. The model and field studies will generate quantitative comparisons of the effects of large and small fires on ungulate survival and will thereby permit the simulation of the effects of alternative fire management scenarios.

scholarly journals Predicting biomass partitioning to root versus shoot in corn and velvetleaf (Abutilon theophrasti)

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 133-137 ◽  
Author(s):  
Kimberly D. Bonifas ◽  
John L. Lindquist
Keyword(s):  
Root Biomass ◽  
Plant Biomass ◽  
Growing Season ◽  
Belowground Biomass ◽  
Biomass Partitioning ◽  
Coordination Model ◽  
Normalized Error ◽  
C And N ◽  
Nitrogen Treatments ◽  
Daily Gain

Knowledge of how plants will partition their new biomass will aid in understanding competition between crops and weeds. This study determined if the amount of biomass partitioned to the root versus the shoot can be predicted from tissue carbon [C] and nitrogen [N] concentrations and the daily gain in C (GC) and N (GN) for each unit shoot and root biomass, respectively. Pots measuring 28 cm diameter and 60 cm deep were embedded in the ground, and each contained one plant of either corn or velvetleaf. Each plant received one of three nitrogen treatments: 0, 1, or 3 g of nitrogen applied as ammonium nitrate in 2001 and 0, 2, or 6 g of nitrogen in 2002. Measurements of total above- and belowground biomass and tissue [C] and [N] were made at 10 different sample dates during the growing season. Fraction of biomass partitioned to roots (Pr) was predicted from [C], [N], GC, and GN. Accurate prediction of the fraction of biomass partitioned to roots versus shoots was evaluated by comparing observed and predicted Pr across all treatments. The coordination model has potential as a reliable tool for predicting plant biomass partitioning. Normalized error values were close to zero for corn in 2001 and 2002 and for velvetleaf in 2001, indicating that biomass partitioning was correctly predicted.

scholarly journals Plant Responses to Spring Grazing by Elk in Yellowstone National Park

1990 ◽  
Vol 14 ◽  
pp. 147-150
Author(s):  
Evelyn Merrill ◽  
Nancy Stanton
Keyword(s):  
Population Growth ◽  
Yellowstone National Park ◽  
National Park ◽  
Plant Responses ◽  
Ecosystem Degradation ◽  
Controversial Subject ◽  
Winter Range ◽  
Northern Winter ◽  
Natural Regulation

Management of elk on the northern winter range of Yellowstone National Park has remained a controversial subject through most of this century (Singer 1989). Until 1968 elk were artificially controlled because it was believed that ranching outside the park excluded elk from winter ranges resulting in unnaturally high populations in the Park and uncontrolled elk numbers would result in overgrazing and ecosystem degradation. However, in 1968 elk reductions were terminated and by 1971 a hypothesis of natural regulation was formulated by Park biologists (Singer 1989). The natural regulation hypothesis asserts that the Yellowstone area used by elk is an ecologically complete habitat (all required components of the habitat are present) and that density dependant factors will limit population growth of elk without major range degradation.

Length and Timing of Grazing on Postburn Productivity of Two Bunchgrasses in an Idaho Experimental Range

1998 ◽  
Vol 8 (1) ◽  
pp. 15 ◽  
Author(s):  
SC Bunting ◽  
R Robberecht ◽  
GE Defosse
Keyword(s):  
Growing Season ◽  
Grazing Management ◽  
Plant Mortality ◽  
Grazing Tolerance ◽  
Regeneration Period ◽  
Postfire Regeneration ◽  
Defoliation Treatment ◽  
Management Policies ◽  
Festuca Idahoensis ◽  
Agropyron Spicatum

Plant mortality and productivity in semiarid grasslands may be affected by the length of time grazing is excluded during the postfire regeneration period. The degree of grazing tolerance for the semiarid bunchgrass species, Festuca idahoensis and Agropyron spicatum, exposed to fire, and how the variation in grazing tolerance was affected by the length of time allowed for undisturbed plant regeneration after fire, were central questions addressed in this study. We examined the degree of plant mortality and productivity that resulted from the interaction of fire and grazing. Plants exposed to fire alone, i.e., without subsequent defoliation, exhibited low plant mortality, although culm production was reduced relative to unburned plants. An early-season-defoliation treatment after fire resulted in the plant mortality as high as 50% for Festuca and 70% for Agropyron bunchgrasses. Plant height and the number of vegetative and reproductive culms were also most affected by this defoliation treatment. These detrimental effects were lessened when defoliation was delayed by one growing season after the fire. Although our results suggest that one growing season seems to be enough for both species to recover after the fire, more studies will be necessary to confirm these trends, and induce changes in current grazing management policies.

Sign in / Sign up

Export Citation Format

Share Document