Grazing and Range Management

Improvement in the Inland: Culture and Nature in the Australian Rangelands

by Nicholas Gill

with Kay Anderson, 2005, Australian Humanities Review, 34, www.australianhumanitiesreview.org

An individual-based model of swan-macrophyte conflicts on a chalk river

by Kevin Wood

Wood, K.A., Stillman, R.A., Daunt, F. & O’Hare, M.T. (2012). An individual-based model of swan-macrophyte conflicts on a chalk river. In: (Eds. Boon, P.J. & P.J. Raven) River Conservation and Management. Wiley-Blackwell, Chichester (UK): pp.339-343.

Foraging mute swans Cygnus olor can cause a substantial reduction of aquatic macrophyte biomass in chalk rivers in... more Foraging mute swans Cygnus olor can cause a substantial reduction of aquatic macrophyte biomass in chalk rivers in southern England. To reduce the adverse effects of this on ecology, hydrology and fisheries interests a river management strategy needs to be able to predict where and when grazing pressure will be greatest. To assess the suitability of mathematical modelling for this purpose, an individual-based model (IBM) was constructed and tested for swans grazing a 1.1km length of the River Frome and adjacent pasture land in Dorset, England. Comparison of predicted and observed data indicates that the model was good at estimating the number of swan days, macrophyte biomass depletion, swan feeding time and feeding patch use. The results indicate that IBMs used at the appropriate scale could help to reconcile river management conflicts involving swans.

Wild sheep and livestock in Nepal Trans-Himalaya: coexistence or competition?

by Rinjan Shrestha

squirespublicationsupdated2012

by Victor SQUIRES

Rural Economy

by Geoffrey Kron

in R. Bagnall, K. Broderson, A. Erskine, S. Heubner (eds.), The Encyclopedia of Ancient History (Oxford: Blackwell, in press

Diversity and distribution of terricolous lichens as indicator of habitat heterogeneity and grazing induced trampling in a temperate-alpine shrub and meadow

by Himanshu Rai

Himanshu Rai, D. K. Upreti and Rajan K. Gupta

Lichens are among the most sensitive biomonitors of ecosystem health and human induced disturbances. Terricolous... more Lichens are among the most sensitive biomonitors of ecosystem health and human induced disturbances. Terricolous lichens of Chopta–Tungnath (Garhwal, western Himalaya, India) were analysed for their ability to indicate habitat variability and disturbances induced by livestock grazing. Terricolous lichens were sampled from 12 sites, distributed across the three macrohabitats between 2,700 and 4,001 m, using 50 × 10 cm narrow frequency grids having five 10 × 10 cm sampling units. The terricolous lichen community of the area constituted, 20 species belonging to 10 genera, five families and four growth forms. Altitude and relative humidity were the major habitat factors found influencing the terricolous lichen community of the landscape. Fruticose and compound soil lichen growth forms were found indicative of habitat disturbance largely caused by grazing induced trampling. Terricolous lichen diversity of the area was delimited by grazing pressure at mid-altitudes (3,000–3,400 m) and by decreasing soil cover at higher altitudes (>3,400 m).

Range shift and winter foraging ecology of a population of Arctic tundra caribou

by Mike Ferguson

Ferguson, Gauthier and Messier.2001. Range shift and winter foraging ecology of a population of Arctic tundra caribou. Canadian Journal of Zoology 79:(5) 746-758

Some researchers have suggested that over periods of several decades, Arctic tundra caribou (Rangifer tarandus) may be... more Some researchers have suggested that over periods of several decades, Arctic tundra caribou (Rangifer tarandus) may be regulated by density-dependent forage depletion. Winter range shifts could potentially delay such regulation when a population is at or near long-term maximum abundance. In the 1980s, Inuit correctly predicted the mass emigration of caribou from a traditional winter range on Foxe Peninsula (FP) on southern Baffin Island, Nunavut, Canada. Most FP caribou subsequently emigrated to a new winter range on Meta Incognita Peninsula (MIP). To determine if MIP provided emigrating caribou with better foraging habitats, we compared winter forage resources and snow cover at caribou foraging sites, and food selection by caribou on FP and MIP in April 1992. Caribou that remained on FP dug feeding craters in shallower, softer snow than those on MIP did. Biomass of most fruticose lichens was greater within foraging sites on MIP than on FP. Biomass of shrubs, other than Cassiope tetragona and Dryas integrifolia, was also greater on MIP than on FP. Dryas integrifolia was the only plant class that had higher biomass on FP than on MIP. Cladina spp. Cladonia spp., Sphaerophorus fragilis, and Cetraria nivalis occurred less frequently in the rumens of FP caribou. Proportions of fruticose lichens in rumens of caribou on both peninsulas were similar to those on other overgrazed and High Arctic tundra winter ranges. Caribou on FP showed a higher preference for the shrub C. tetragona. Biomasses of plants sensitive to long-term feeding or trampling by caribou (i.e., the five most common fruticose lichens, other shrubs, and plant debris) were consistently lower on FP, which is congruous with Inuit reports that long-term cumulative overgrazing had reduced the supply of important forage plants on FP sites that were accessible to caribou in winter. FP caribou that emigrated to MIP gained access to more abundant, higher quality forage resources than those that remained on FP. Because most FP caribou had emigrated, this South Baffin subpopulation escaped, at least temporarily, the regulating effects of historical cumulative overgrazing.

The function of plant richness and diversity on eco-balancing of upland rangeland on Alborz Mountains (North of Iran)

by Ravindra Gavali

Journal of Biodiversity and Ecological Science

Ecological equilibrium of upland rangeland is guaranteed by the conserving of vegetation structures which save an... more Ecological equilibrium of upland rangeland is guaranteed by the conserving of vegetation structures which save an ecosystem from erosion. A range ecosystem can be safe with good condition of plant diversity and richness as symbols of ecosystem balancing. In this research, therefore, two aspects of northwest and northeast rangland from the highest uplands of mountain watersheds in northern Alborz [Javaherdeh - Ramsar] of Iran were selected. Vegetation status of rangeland habitats and soil erosion has been evaluated in two types of shrubland and grassland by the Daubenmire and the PSIAC methods. In order to determine the influence of plant diversity and richness on soil erosion and rangeland conditions, the data has been analyzed using multi regression technique and the mean between the two habitats have been compared using the T-test method using the SPSS software. The results showed that both grassland and shrubland habitats have not only had poor conditions but also much soil erosion. The research findings have also shown that the plant diversity and richness in both
types are significantly related to soil erosion and rangeland conditions. Some vegetation factors have affected both the habitat condition and soil erosion. It appears that the desirable rangeland conditions can be achieved by control of animal grazing which can then lead to the reduction of soil erosion with the help of vegetation canopy cover.

Management of grazing lands in Indian cold desert: A village level study in Spiti valley, India

by Ravindra Gavali

Authors: R. S. Gavali, K. S. Roa, K. G. Saxena, R. K. Maikhuri. Published.

Global Change, Biodiversity and Livelihoods in Cold Desert Region of Asia

Edited by K. G. Saxena, Luohui Liang, Xian Xue, 2011: pages 147-159; United Nations University & BSMPS Publications.

Comparative Ecology of Bison and Cattle on Mixed-Grass Prairie

by Lori Hidinger

A scale-depending grazing gradient in an Artemisia-desert steppe? A case study from western Mongolia.

by Claudia Oehmke

published in Basic and Applied Dryland Research (2007) 1 (1)

Abstract
Data about stand density, above-ground biomass, individual plant weight and the proportion of flowering... more Abstract
Data about stand density, above-ground biomass, individual plant weight and the proportion of flowering plants of the dwarf semi-shrub Artemisia xerophytica were collected along a grazing gradient defined by increasing distance (0 to 2000 m) from grazing hot spots in a desert steppe ecosystem in estern Mongolia. Soil data were used to distinguish between grazing and edaphic influences.
All parameters recorded for Artemisia xerophytica reflect the assumed gradient of grazing intensity up to 800 m distance from the grazing hot spot. As grazing pressure decreases, plant density and total biomass per plot increase. The average shrub weight, an indicator of plant vitality, is related to both: distance from the grazing hot spot and stand density; which may be explained by additional intraspecific competition at higher densities. At a longer distance these effects are masked by variations in soil parameters determining water availability, leading to quite similar degradation forms.
These results are in contrast to other studies carried out at the scale of plant communities, which did not detect significant changes along a grazing gradient. One explanation is the different map scale; our study took place only within a single plant community comparing different populations of one species.

Distributional Correlates of the Tibetan Gazelle Procapra Picticaudata In Ladakh, Northern India: Towards a Recovery Programme

by Sumanta Bagchi

Oryx 42:107-112. (2008)

The Tibetan gazelle Procapra picticaudata is on the verge of extinction in India with only c. 100 individuals... more The Tibetan gazelle Procapra picticaudata is on the verge of extinction in India with only c. 100 individuals remaining in the Hanle Valley of eastern Ladakh and Sikkim. Conservation planning and initiation of a recovery programme are hindered by lack of ecological information on the species and we therefore assessed the biotic and abiotic correlates of its occurrence in the Hanle Valley. Ecological attributes of areas selected by gazelles were compared with those of adjoining areas without gazelles. Resource selection functions revealed that gazelles use relatively flat areas (6-15°) disproportionately during both summer and winter, and preferred south-facing slopes and avoided north-facing slopes during winter. Measurements of plant production using exclosures showed that herbivores removed up to 47% of the forage biomass from areas without gazelles, whereas only 29% was removed from areas with gazelles. Although areas selected by gazelles were only marginally more productive than areas not selected, the proportional representation of forbs in plant biomass was significantly higher in the former. Spatial co-occurrence patterns examined using null models revealed a significant negative relationship between distribution of gazelles and goats and sheep, and a significant positive relationship between gazelles and wild kiang Equus kiang and domestic yak Bos grunniens. Future in situ recovery programmes for the Tibetan gazelle in Ladakh need to focus on securing livestock-free, forb-dominated areas, with participation from the local pastoral community.

Small Mammalian Herbivores As Mediators of Plant Community Dynamics In the High-Altitude Arid Rangelands of Trans-Himalaya

by Sumanta Bagchi

Biological Conservation 127: 438-442. (2006)

The high-altitude rangelands of the Trans-Himalaya represent a grazing ecosystem which has supported an indigenous... more The high-altitude rangelands of the Trans-Himalaya represent a grazing ecosystem which has supported an indigenous pastoral community for millennia alongside a diverse assemblage of wild herbivores including burrowing mammals (pikas and voles). Pastoralists consider the small mammals to cause rangeland degradation and as competitors for their livestock, and actively eradicate them at many places. We present data on the ways in which small herbivores like pikas and voles mediate plant community dynamics. Vegetation cover and plant species richness were compared on and off both active and abandoned small mammal colonies. Plant species richness was higher inside colonies (about 4–5 species/plot) than outside (about 3 species/plot) whereas vegetation cover was only marginally lower (52% compared to 60%). Soil disturbance due to small mammals is seen to be associated with higher plant diversity without causing dramatic decline in overall vegetation cover. Such disturbance-mediated dynamics and vegetation mosaics produce a rich array of testable hypotheses that can highlight how small mammals influence assembly processes, succession, and dominance hierarchies in plant communities in this arid ecosystem. So, eradicating small mammals may lead to declining levels of diversity in this ecosystem, and compromise ecosystem-functioning. Changes in traditional pastoral practices and overstocking are more likely to be responsible for degradation. We emphasize that eradicating small mammals can lead to loss of diversity in this ecosystem and it is not a solution for the degradation problems.

Conflicts Between Traditional Pastoralism and Conservation of Himalayan Ibex (Capra Sibirica) In the Trans‐Himalayan Mountains

by Sumanta Bagchi

Animal Conservation 7: 121-128. (2004)

There is recent evidence to suggest that domestic livestock deplete the density and diversity of wild herbivores in... more There is recent evidence to suggest that domestic livestock deplete the density and diversity of wild herbivores in the cold deserts of the Trans-Himalaya by imposing resource limitations. To ascertain the degree and nature of threats faced by Himalayan ibex (Capra sibirica) from seven livestock species, we studied their resource use patterns over space, habitat and food dimensions in the pastures of Pin Valley National Park in the Spiti region of the Indian Himalaya. Species diet profiles were obtained by direct observations. We assessed the similarity in habitat use and diets of ibex and livestock using Non-Metric Multidimensional Scaling. We estimated the influence of the spatial distribution of livestock on habitat and diet choice of ibex by examining their co-occurrence patterns in cells overlaid on the pastures. The observed co-occurrence of ibex and livestock in cells was compared with null-models generated through Monte Carlo simulations. The results suggest that goats and sheep impose resource limitations on ibex and exclude them from certain pastures. In the remaining suitable habitat, ibex share forage with horses. Ibex remained relatively unaffected by other livestock such as yaks, donkeys and cattle. However, most livestock removed large amounts of forage from the pastures (nearly 250 kg of dry matter/day by certain species), thereby reducing forage availability for ibex. Pertinent conservation issues are discussed in the light of multiple-use of parks and current socio-economic transitions in the region, which call for integrating social and ecological feedback into management planning.

NICHE RELATIONSHIPS OF AN UNGULATE ASSEMBLAGE IN A DRY TROPICAL FOREST

by Sumanta Bagchi

Journal of Mammalogy 84: 981-988. (2003)

Niches of 2 cervids (chital, Axis axis and sambar, Cervus unicolor) and 2 bovids (nilgai,
Boselaphus tragocamelus... more Niches of 2 cervids (chital, Axis axis and sambar, Cervus unicolor) and 2 bovids (nilgai,
Boselaphus tragocamelus and chinkara, Gazella bennetti) from semiarid forests in western
India were studied for habitat use and food habits. Habitat use was analyzed by discriminant
analysis using 20 variables, and food habits investigated by analyzing undigested plant
remains in pellets. Cervids and bovids differentiated primarily according to vegetation and
terrain features, and the 2 deer species showed separation in diet. The 2 cervids selected
forested areas, whereas the 2 bovids selected scrubland and were more tolerant of disturbances
like livestock grazing and also showed a high similarity in food habits. Habitat use
and food habits were analyzed with nonmetric multidimensional scaling to assess their
combined effects. A greater degree of similarity in resource use between the 2 bovids
suggests that they may be competitive, at least during periods of forage scarcity.

Herbivore Effects on Above-and Belowground Plant Production and Soil Nitrogen Availability In the Trans-Himalayan Shrub-Steppes

by Sumanta Bagchi

Oecologia 164:1075-1082. (2010)

Large mammalian herbivores may have positive, neutral, or negative effects on annual net aboveground plant production... more Large mammalian herbivores may have positive, neutral, or negative effects on annual net aboveground plant production (NAP) in different ecosystems, depending on their indirect effects on availability of key nutrients such as soil N. In comparison, less is known about the corresponding influence of grazers, and nutrient dynamics, over annual net belowground plant production (NBP). In natural multi-species plant communities, it remains uncertain how grazing influences relative allocation in the above- and belowground compartments in relation to its effects on plant nutrients. We evaluated grazer impacts on NAP, NBP, and relative investment in the above- and belowground compartments, alongside their indirect effects on soil N availability in the multiple-use Trans-Himalayan grazing ecosystem with native grazers and livestock. Data show that a prevailing grazing intensity of 51% increases NAP (+61%), but reduces NBP (−35%). Grazing also reduced C:N ratio in shoots (−16%) and litter (−50%), but not in roots, and these changes coincided with increased plant-available inorganic soil N (+23%). Areas used by livestock and native grazers showed qualitatively similar responses since NAP was promoted, and NBP was reduced, in both cases. The preferential investment in the aboveground fraction, at the expense of the belowground fraction, was correlated positively with grazing intensity and with improvement in litter quality. These results are consistent with hypothesized herbivore-mediated positive feedbacks between soil nutrients and relative investment in above- and belowground compartments. Since potentially overlapping mechanisms, such as N mineralization rate, plant N uptake, compositional turnover, and soil microbial activity, may contribute towards these feedbacks, further studies may be able to discern their respective contributions.

Introduced Grazers Can Restrict Potential Soil Carbon Sequestration Through Impacts on Plant Community Composition

by Sumanta Bagchi

Ecology Letters 13: 959-968. (2010)

Grazing occurs over a third of the earth’s land surface and may potentially influence the storage of 109 Mg year^−1 of... more Grazing occurs over a third of the earth’s land surface and may potentially influence the storage of 109 Mg year^−1 of greenhouse gases as soil C. Displacement of native herbivores by high densities of livestock has often led to overgrazing and soil C loss. However, it remains unknown whether matching livestock densities to those of native herbivores can yield equivalent soil C sequestration. In the Trans-Himalayas we found that, despite comparable grazing intensities, watersheds converted to pastoralism had 49% lower soil C than watersheds which retain native herbivores. Experimental grazer-exclusion within each watershed type, show that this difference appears to be driven by indirect effects of livestock diet selection, leading to vegetation shifts that lower plant production and reduce likely soil C inputs from vegetation by c. 25 gC m^−2 year^−1. Our results suggest that while accounting for direct impacts (stocking density) is a major step, managing indirect impacts on vegetation composition are equally important in influencing soil C sequestration in grazing ecosystems.

Multiple Use of Trans-Himalayan Rangelands: Reconciling Human Livelihoods With Wildlife Conservation

by Sumanta Bagchi

Book chapter (2009).
In du Toit, J., R. Kock, & J. Deutsch (eds.), Wild rangelands: Conserving wildlife while maintaining livestock in semi-arid ecosystems. Blackwell Publishing, London.

Keywords:

Trans-Himalayan rangeland multiple use;reconciling human livelihoods with wildlife... more Keywords:

Trans-Himalayan rangeland multiple use;reconciling human livelihoods with wildlife conservation;Trans-Himalayan rangeland wildlife;Trans-Himalayan mountain ungulates;pastoralism in Trans-Himalaya;livestock species diversity and herding practices;livestock grazing intensity and buffer or multiple-use landscape unit;Project Snow Leopard - Trans-Himalayan rangeland conservation;conservation management in Trans-Himalayan rangelands;human–wildlife conflicts and flexible and community-based management

Herbivory and Plant Tolerance: Experimental Tests of Alternative Hypotheses Involving Non-Substitutable Resources

by Sumanta Bagchi

Oikos 120:119-127. (2011)

A mechanistic understanding of the highly variable effects of herbivores on plant production in different ecosystems... more A mechanistic understanding of the highly variable effects of herbivores on plant production in different ecosystems remains a major challenge. To explain these patterns, the compensatory continuum hypothesis (CCH) predicts plants to compensate for defoliation when resources are abundant, whereas the growth rate hypothesis (GRH) makes the opposite claim of high herbivory tolerance under resource-poor conditions. The limiting resource model (LRM) tries to reconcile this dichotomy by incorporating the indirect effects of herbivores on plant resources and predicts that the potential for plant compensation is dependent upon whether, and how, herbivory influences limiting resources. Although extensively evaluated in laboratory monocultures, it remains uncertain whether these models can also explain the response of heterogeneous and multi-species natural plant communities to defoliation. Here we investigate community-wide plant response to defoliation and report data from a field experiment in the arid and primarily water-limited Trans-Himalayan grazing ecosystem in northern India involving clipping, irrigation and nutrient-feedback with herbivore dung. Without nutrient-feedback, plants compensated for defoliation in absence of irrigation but failed to compensate under irrigation. Whereas, in the presence of nutrient-feedback plants compensated for defoliation when irrigated. This divergent pattern is not consistent with the CCH and GRH, and is only partially explained by the LRM. Instead, these pluralistic results are consistent with the hypothesis that herbivory may alter the relative strengths of water and nutrient limitation since irrigation increased root:shoot ratio in absence of fertilization in unclipped plots, but not in the corresponding clipped plots. So, herbivory appears to increase relative strength of nutrient-limitation for plants that otherwise seem to be primarily water-limited. Extending the LRM framework to include herbivore-mediated transitions between water and nutrient-limitation may clarify the underlying mechanisms that modulate herbivory-tolerance under different environmental conditions.

Relative contribution of delaying senescence to growth compensation after defoliation

by Iker Dobarro

DOBARRO, I., GAZOL, E. & PECO, B. 2011. Relative contribution of delaying senescence to growth compensation after defoliation.Ecological Research. DOI: 10.1007/s11284-011-0901-9

Delaying senescence as a response to tissue losses has been reported in some studies, but there is not information... more Delaying senescence as a response to tissue losses has been reported in some studies, but there is not information about its influence in growth compensation. We performed a first test of the relative contribution of delaying senescence after defoliation to growth compensation in Dactylis glomerata L. by means of an iterative growth analysis modified to estimate tissue losses to senescent leaves. Dactylis glomerata overcompensated for relative growth rate after defoliation, mainly reducing the amount of tissue that enters in senescence, and partially increasing the newly assimilated mass allocated to leaves.