Livestock grazing is associated with seasonal reduction in pollinator biodiversity and functional dispersion but cheatgrass invasion is not: variation in bee assemblages in a multi-use shortgrass prairie

AbstractLivestock grazing and non-native plant species affect rangeland habitats globally. These factors may have important effects on ecosystem services including pollination, yet, interactions between pollinators, grazing, and invasive plants are poorly understood. To address this, we tested the hypothesis that cattle grazing and site colonization by cheatgrass (Bromus tectorum) impact bee foraging and nesting habitats, and the biodiversity of wild bee communities, in a shortgrass prairie system. Bee nesting habitats (litter and wood cover) were marginally improved in non-grazed sites, though foraging habitat (floral cover and richness) did not differ among grazed, non-grazed, or cheatgrass colonized sites. However, floral cover was a good predictor of bee abundance and functional dispersion. Mean bee abundance, richness, diversity and functional diversity were significantly lower in cattle-grazed habitats than in cheatgrass-colonized or non-grazed habitats. Differences in bee diversity among habitats were pronounced early in the growing season (May) but by late-season (August) these differences eroded. Fourth-corner analysis revealed that sites with high floral cover tended to support large, social, polylectic bees; sites with high grass cover tended to support oligolectic solitary bees. Both cattle-grazed and cheatgrass-colonized sites were associated with lower abundances of above-ground nesting bees but higher abundance of below-ground nesters. We conclude that cheatgrass-invaded sites are not associated with reduced bee biodiversity or abundance, but cattle grazing was negatively associated with bee abundances and altered species composition. Although floral cover is an important predictor of bee assemblages, this was not impacted by grazing and our suggests that cattle likely impact bee communities through effects other than those mediated by forbs, including soil disturbance or nest destruction. Efforts aimed at pollinator conservation in prairie habitats should focus on managing cattle impacts early in the growing season to benefit sensitive bee species.

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Livestock grazing is associated with seasonal reduction in pollinator biodiversity and functional dispersion but cheatgrass invasion is not: Variation in bee assemblages in a multi-use shortgrass prairie

PLoS ONE ◽

10.1371/journal.pone.0237484 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0237484

Author(s):

Khum Bahadur Thapa-Magar ◽

Thomas Seth Davis ◽

Boris Kondratieff

Keyword(s):

Growing Season ◽

Cattle Grazing ◽

Bare Soil ◽

Soil Disturbance ◽

Livestock Grazing ◽

Native Plant ◽

Shortgrass Prairie ◽

Functional Dispersion ◽

Bee Communities ◽

Bee Abundance

Livestock grazing and non-native plant species affect rangeland habitats globally. These factors may have important effects on ecosystem services including pollination, yet, interactions between pollinators, grazing, and invasive plants are poorly understood. To address this, we tested the hypothesis that cattle grazing and site colonization by cheatgrass (Bromus tectorum) impact bee foraging and nesting habitats, and the biodiversity of wild bee communities, in a shortgrass prairie system. Bee nesting habitats (litter and wood cover) were marginally improved in non-grazed sites with low cheatgrass cover, though foraging habitat (floral cover and richness, bare soil) did not differ among cattle-grazed sites or non-grazed sites with low or high cheatgrass cover. However, floral cover was a good predictor of bee abundance and functional dispersion. Mean bee abundance, richness, diversity and functional diversity were significantly lower in cattle-grazed habitats than in non-grazed habitats. Differences in bee diversity among habitats were pronounced early in the growing season (May) but by late-season (August) these differences eroded as Melissodes spp. and Bombus spp. became more abundant at study sites. Fourth-corner analysis revealed that sites with high floral cover tended to support large, social, polylectic bees; sites with high grass cover tended to support oligolectic solitary bees. Both cattle-grazed sites and sites with high cheatgrass cover were associated with lower abundances of above-ground nesting bees but higher abundance of below-ground nesters than non-grazed sites with low cheatgrass cover. We conclude that high cheatgrass cover is not associated with reduced bee biodiversity or abundance, but cattle grazing was negatively associated with bee abundances and altered species composition. Although floral cover is an important predictor of bee assemblages, this was not impacted by cattle grazing and our study suggests that cattle likely impact bee communities through effects other than those mediated by forbs, including soil disturbance or nest destruction. Efforts aimed at pollinator conservation in prairie habitats should focus on managing cattle impacts early in the growing season to benefit sensitive bee species.

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Individual plant species responses to phosphorus and livestock grazing

Australian Journal of Botany ◽

10.1071/bt11149 ◽

2011 ◽

Vol 59 (7) ◽

pp. 670 ◽

Cited By ~ 26

Author(s):

J. Dorrough ◽

S. McIntyre ◽

M. P. Scroggie

Keyword(s):

Species Composition ◽

Plant Species ◽

Native Species ◽

Livestock Grazing ◽

Individual Species ◽

Available Phosphorus ◽

Individual Plant ◽

Plant Species Composition ◽

Native Plant ◽

Native Plant Species

Livestock grazing and fertilisation are primary management activities that determine variation in plant species composition within grazed temperate grassy ecosystems of Australia. The present paper provides an extensive catalogue of the responses of individual species to grazing and fertilisation that can be used to guide management and restoration in differing situations. A hierarchical model that links plant species identities, simple plant traits and two continuous predictive variables (livestock density and available phosphorus) was used to estimate probability of occurrence of plant species across grazing and phosphorus gradients. Certain species and groups of species, particularly native perennial geophytes, ferns and shrubs, were especially sensitive to increases in each of these management gradients, whereas a small group of exotic plants were most tolerant. In the moderately intensive livestock production landscapes sampled, most native plant species preferred ungrazed areas with low available phosphorus. Many non-native plant species also tolerated or preferred such habitats. Less than 1% of all observed species are predicted to occur at high levels of available phosphorus (75 mg kg–1) and heavy stocking (9 dry sheep equivalents ha–1). There is, however, a suite of native species that persist at moderate livestock densities, but only if soils are not phosphorus-enriched. These data can be used to guide options for restoration including ranking of potential sites or selection of species for reintroduction. In most cases, livestock grazing intensity is thought to be the primary factor influencing plant species composition in grazed woodlands. These data, however, highlight the great importance of fertilisation history in limiting ground-layer plant diversity and determining options for management.

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Increasing Native Plant Species Richness can Increase Ecosystem Multifunctionality under Intense Livestock Grazing

10.31274/farmprogressreports-180814-1266 ◽

2010 ◽

Author(s):

Forest I. Isbell ◽

Brian J. Wilsey

Keyword(s):

Species Richness ◽

Plant Species ◽

Plant Species Richness ◽

Livestock Grazing ◽

Native Plant ◽

Native Plant Species ◽

Ecosystem Multifunctionality

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A Guide to Planting Wildflower Enhancements in Florida

EDIS ◽

10.32473/edis0in1180-2017 ◽

2017 ◽

Vol 2017 (5) ◽

Author(s):

Mary C. Bammer ◽

Josh Campbell ◽

Chase B. Kimmel ◽

James D.. Ellis ◽

Jaret C. Daniels

Keyword(s):

Management Practices ◽

Insect Pests ◽

Native Plant ◽

Agricultural Producers ◽

Native Plant Species ◽

Control Techniques ◽

Wild Bee ◽

Pollinator Species ◽

Nesting Sites ◽

The Right

The establishment of native wildflower plantings in Florida can benefit agricultural producers as well as native pollinators and other beneficial insects (predators and parasitoids). The plantings do this by: providing forage and nesting sites for bees, butterflies, and other pollinators, increasing wild bee numbers possibly across the farm, and increasing natural enemies of insect pests (that also depend on forage and nesting sites). This document discusses choosing the right mix of native plant species to benefit many pollinator species, as well as proper site selection, planting practices, and weed control techniques. Wildflower plots should be practical to manage, maximize benefits to wildlife, and fit into the overall management practices of the property.

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