Upland Grassland Research Articles

The Effects of Soil Acidity and Aluminium on the Root Systems and Shoot Growth of Lotus pedunculatus and Lupinus polyphyllus.

Lotus pedunculatus (lotus) and Lupinus polyphyllus (Russell lupin) persist in the upland grasslands of New Zealand, where soil acidity and associated aluminium (Al) toxicity impede conventional pasture legumes. This experiment investigated the response of lotus and Russell lupin to soil acidity and Al. The species were sown in 20 cm tall 1.2 L pots of acidic upland soil. A mass of 4.5 or 6.7 g lime (CaCO3)/L was added to either the top or bottom or both soil horizons (0-9 cm and 9-18 cm), resulting in six treatments across six randomised blocks in a glasshouse. The soil pH was 4.4, 4.9, and 5.4; the exchangeable Al concentrations were 24, 2.5, and 1.5 mg/kg for 0, 4.5, and 6.7 g lime/L. At 16 weeks post-sowing, the plants were divided into shoots and roots at 0-9 cm and 9-18 cm. Root morphology, shoot and root dry matter (DM), shoot nitrogen (N), and nodulation were measured. The total plant DM and shoot-to-root DM ratio were higher, and the shoot %N was lower for the lotus plants than the Russell lupin plants for the various lime rates (13.2 vs. 2.9 g plant-1, 5.6 vs. 1.6, and 2.4 vs. 3.3%, p < 0.05). No response to lime in terms of total DM or total root morphology parameters was exhibited in either species (p > 0.05). Root morphology adjustments in response to acidity between soil horizons were not observed. The results indicated that lotus and Russell lupin are tolerant to high soil acidity (pH 4.4-5.4) and exchangeable Al (1.5-24 mg kg-1), highlighting their considerable adaptation to grasslands with acidic soils.

Soil pH and phosphorus availability regulate sulphur cycling in an 82-year-old fertilised grassland

The application of lime and mineral fertiliser is known to mitigate soil acidification and improve soil quality in improved grasslands. However, the long-term effect of simultaneous lime and fertiliser amendments on soil carbon (C) and sulphur (S) cycling is still poorly understood. To examine if soil pH or nutrient availability are the dominant factors regulating C and S cycling, we evaluated the biodegradation of methionine (organic S), gross S transformation, and microbial S utilisation using 35S and 14C dual-labelling. Soil samples (0–10 cm) were collected from one unfertilised control and five annual limed (Ca) treatments with or without nitrogen (N), phosphorus (P), potassium (K) and sulphur (S) fertilisers (Ca, CaN, CaNP, CaNPKCl, CaNPK2SO4) in an 82-year-old upland grassland experiment in Rengen, Germany. Long-term lime application increased soil pH values but significantly (p < 0.05) decreased soil organic C content. Fertilisation had no significant effect on microbial utilisation of 35S-labelled methionine, while microbial immobilisation of 35SO42− in the limed soils was significantly reduced compared to the control. This is attributed to either the increased soil pH or decreased C availability after liming. Microbial carbon use efficiency (CUE) was significantly higher in soils with applied P fertiliser (i.e., CaNP: 0.66 ± 0.02, CaNPKCl: 0.68 ± 0.02, CaNPK2SO4: 0.65 ± 0.01) compared to the CaN treatment (0.58 ± 0.01). Moreover, compared to CaN, CaNP and CaNPKCl treatments significantly increased gross S turnover, while no significant effects were observed in the CaNPK2SO4 treatment. Soil P deficits decreased microbial CUE and S bioavailability. Although P fertiliser addition alleviated microbial P limitation when N fertiliser was added, S fertiliser (CaNPK2SO4) present constrained S transformation rates. Overall, the importance of P availability for global S cycling in grasslands is shown, especially under N-enrichment conditions. However, the subsequent potential for C loss from long-term liming should be carefully considered in grassland management.

Regional emissions of soil greenhouse gases across Tibetan alpine grasslands

Soil greenhouse gas (GHG) emissions play an important role in regional climate feedback on the Qinghai-Tibetan Plateau (QTP). Previous studies have focused on soil GHGs based on observations within a limited space on the QTP, however, the regional GHG emissions remain unclear. Analyzing soil samples from 25 sites along a 2,700 km transect across QTP, we showed significantly higher soil CO2 and N2O emission rates in alpine meadows than other upland grassland types, but similar soil CH4 uptake rates across all grassland types. The spatial variations of total soil GHG balance were dominated by CO2 emission. We found that CO2 emission was primarily constrained by high soil pH, low soil moisture and nutrient availability, and fungal abundance, N2O emission was inhibited by high soil pH, while CH4 uptake was dominated by methanotrophic abundance. Furthermore, we estimated a current regional total soil GHG balance of 144.4 Tg CO2-eq yr−1 for surface soil across Tibetan alpine grasslands, which increased by 17.6%, 24.8%, and 38.9% under warming scenarios of 1.5℃, 2℃ and 3℃, respectively. Our results provide a baseline for regional soil GHG emissions responding to climate warming on the QTP.

One Year of Grassland Vegetation Dynamics in Two Sheep-Grazed Agrivoltaic Systems

In agrivoltaic systems with solar fixed panels, the provision of ecosystem services by agricultural productions could be compromised due to very large changes in plant microclimate. But we still do not know properly the changes in grasslands ecosystem services. On two sheep-grazed sites located in lowland (Braize, Br) and upland (Marmanhac, Ma) grasslands of central France, we studied for one year the direct effects of various shading conditions induced by solar fixed panels on abiotic variables (light, water and soil temperature) and on vegetation (daily growth height, forage quantity and quality, number of species). Under exclosure of grazing, three treatments per site were set up, control (without solar-panel influence), inter-rows (variable influence) and panel (full influence). The results showed that light was reduced by 93% on average over the year in the shade of the panels with a cooler soil temperature of 2.6°C on Ma and 3.4°C on Br compared to the control. However, the soil moisture response varied between sites, depending on the different seasonal rainfall events and on soil texture. This resulted in 2.6 (Ma) to 3.2 (Br) times faster daily height growth and better forage quality. However, annual biomass production and species number showed no difference between the control and the panel. Only the inter-row treatment, which receives variable shading conditions throughout the day and seasons, shows variable biomass responses across sites. Experimental work will continue for several years in order to parameterise models to simulate the ecosystem services of agrivoltaic parks over the long term.

The influence of landscape composition and configuration on breeding waterfowl pair abundance in Wisconsin

AbstractHabitat loss and fragmentation have negatively impacted breeding birds across the world. Across guilds, grassland‐dependent birds have experienced the largest proportional loss of their breeding population while wetland‐dependent birds have realized overall net gains in part due to focused conservation efforts. However, some species within the wetland‐dependent guild have a strong dependence on non‐wetland land cover types during the annual cycle and therefore may be equally sensitive to reductions in the composition and altered configuration of upland landcover, such as grasslands. We explored the influence of landcover composition and configuration on the number of breeding pairs of a breeding habitat generalist, the mallard (Anas platyrhynchos), and a grassland‐dependent breeding species, the blue‐winged teal (Spatula discors), in agriculturally‐intensive landscapes of Wisconsin, USA. Because of the extensive landscape alteration and habitat fragmentation that has occurred, we expected mallards to have a more utilitarian response to varying landscape composition compared to a grassland nesting obligate like blue‐winged teal. We used helicopter surveys conducted across 8 years (2001–2003, 2006–2009, and 2012) and remotely‐sensed land cover data to investigate the influence of habitat associations on relative abundance of breeding pairs. Model selection indicated that landscape composition models outperformed landscape configuration and null models for both species. Consistent with our predictions, we found that mallard pair counts were positively influenced by a greater number of land cover covariates compared to blue‐winged teal. Both blue‐winged teal and mallard breeding pairs were positively related to increased composition of emergent and scrub‐shrub wetlands as well as upland grassland. Additionally, we found that mallard pairs were positively related to forested, cattail (Typha sp.), and open water wetland types, whereas predicted blue‐winged teal pair abundance was negatively related to forested wetlands and had a nonlinear relationship and declined when surveyed land sections were comprised of more than 30% cattail‐dominated wetlands and 20% open‐water wetlands. Increased quantities of cattail‐dominated and open‐water wetland cover types comparatively provide less habitat for blue‐winged teal and may reflect broader shifts in habitat composition that have likely resulted from agricultural intensification and stabilized hydrology. Conservation activities that preserve existing nesting land cover types or restore hydrologically‐dynamic emergent wetlands in proximity to upland grassland cover could mutually benefit both species.

Management of grassland: A necessary tool to maintain plant and earthworm diversity

In temperate grassland, earthworms contribute to the major soil processes which determine most of the ecosystem services. The characteristics of plant communities in grassland are key factors in maintaining earthworm communities, however effects of different herbage management on earthworms remain largely unknown. In this context, the aim of the present study was to determine the long-term effects of herbage management on grassland plant and earthworm communities. Plants and earthworms were sampled in a 14-years-old experiment in upland grasslands (Massif central, France). Abandoned grasslands were compared with mowed grasslands and with pastures grazed by cattle (at low or high intensities) or grazed by sheep (at low intensity). Compared to abandoned grassland, herbage management by grazing or by mowing display higher leguminous plant, community-weighted mean Ellenberg light values as well as plant richness while they display lower percentage of plant litter and community-weighted mean Ellenberg nitrogen values. The differences in plant richness were associated with a significant change in plant community structure. Compared to the abandoned grassland, herbage management by grazing or mowing significantly display higher earthworm biomass and total richness. Except for pastures grazed by cattle at high intensity, earthworm abundance was at least twice that in the grassland at low grazing intensity or mowing compared to the abandoned grassland. Earthworm communities were significantly different between grazed and mown treatments notably due to changes within Aporrectodea anecic and endogeic earthworm species. Overall, herbage management by animals or by mechanical export is beneficial for plant and earthworm diversity although no clear differences between management practices for earthworm richness, total biomass or total abundance were observed. Our results highlight that abandonment does not preserve biodiversity (plant, soil macrofauna) while management of grassland by grazing or mowing is a necessary tool for biodiversity conservation and improvement.

Experimental warming outside the growing season and exclusion of grazing has a mild effect on upland grassland plant communities in the short term

ABSTRACT Background Winters are expected to warm more than summers in central and northern Europe, with largely unknown effects on grassland plant communities. Aims By studying the interactions between winter warming and summer grazing, we aimed to disentangle their effects and give recommendations for future grassland management. Methods Our study area Upper Teesdale, England has winter temperatures close to 0°C and a well-studied vegetation, known for its arctic-alpine species growing at their climatic warm range limits. We set up a winter warming experiment using open top chambers (ca. +0.5°C) from mid-September until mid-May 2019 to 2022 and excluded sheep grazing during summer in a fully factorial design. Results Graminoid biomass increased, and bryophyte biomass decreased with winter warming. There was little to no evidence that winter warming affected any of the other plant response variables we measured, neither did grazing nor the interaction between winter warming and grazing. Conclusions Our experiment was relatively short in duration and treatments were realistic in magnitude, therefore the plant communities responded only slightly. Nevertheless, our data suggest a change towards more dominant vascular species and less bryophytes with winter warming, which might lead to lasting changes in the plant communities in the longer-term if not buffered by suitable grazing management.

Acidification of previously limed upland pastures – An overlooked flood risk factor?

In low-lying land, the impact of agriculture on flooding has focussed on soil compaction, whilst in the uplands there has been more interest in the influence of afforestation. The potential effect of acidification of previously limed upland grassland soils on this risk has been overlooked. The marginal economics of upland farms has led to inadequate lime application on these grasslands. In Wales, UK, agronomic improvement of upland acid grasslands with liming was widespread in the last century. The extent and topographical distribution of this land use in Wales was estimated and these characteristics were mapped in four catchments studied in more detail. Then 41 sites on improved pastures within the catchments were sampled, where lime had not been applied for periods of between two and 30 years; unimproved acid pastures adjacent to five of these sites were also sampled. Soil pH, organic matter, infiltration rates and earthworm populations were recorded. Grasslands at risk of acidification without maintenance liming were estimated to cover almost 20 % of upland Wales. The majority of these grasslands were located on steeper slopes (gradients >7o) where any reduction in infiltration would promote surface runoff and limit rainwater retention. The extent of these pastures varied markedly between the four study catchments. There was a 6-fold reduction in infiltration rates between high and low pH soils, and this trend was correlated with reductions in anecic earthworm abundance. The vertical burrows of these earthworms are important for infiltration and no such earthworms were present in the most acidic soils. Recently limed soils had infiltration rates similar to those of unimproved acid pastures. Soil acidification has the potential to exacerbate flood risk but further research is needed to assess the extent of any impact. Modelling of catchment specific flood risk should include the extent of upland soil acidification as an additional land use factor.

Inter-annual drought monitoring in northern mixed grasslands by a revised vegetation health index from historical Landsat imagery

Drought is defined as a natural phenomenon with comprehensive influences on ecosystems, economies, and the livelihood and health of people resident in the affected regions. Severe drought has affected the grassland ecosystem in the Canadian prairie region with increased frequency. Thus, it is essential to monitor the drought effects. With various temporal, spectral, and spatial resolutions, remote sensing data can detect vegetation's dynamic responses to drought. The objective of this study was to monitor inter-annual drought in the northern mixed grassland, over the last thirty-six years by using remote sensing approach through a revised vegetation health index (VHIr), which combined the vegetation condition index (VCI), the temperature condition index (TCI), and the dead fuel condition index (DCI) together. Historical Landsat imagery was explored to establish the VHIr and this index was tested in the Grasslands National Parks (GNP), a typical conserved northern mixed grasslands region. The results suggested that the VHIr can distinguish dry and wet years effectively and a VHIr map was able to depict the spatial distribution pattern of the drought severity. Compared with the original vegetation health index (VHI), VHIr was more correlated with the dead-to-green biomass ratio. Meanwhile, the spatial pattern indicated that the valley grasslands had relatively low drought sensitivity; the upland grasslands experienced severe to extreme drought severity during dry years, due to a large amount of dead vegetation existed; and the drought effect on sloped grasslands was due to relatively sparse vegetation cover. In addition, VHIr was significantly correlated with greenness and wetness components derived from the tasseled cap (K-T) transformation but the correlation coefficients (r) varied between dry and wet years and among different grassland landscapes. This study expanded our understanding of the spatial and temporal distribution of drought severity in the northern mixed grasslands, which can facilitate natural resource management in the arid and semi-arid regions.

Local and landscape environmental heterogeneity drive ant community structure in temperate seminatural upland grasslands.

Environmental heterogeneity is an important driver of ecological communities. Here, we assessed the effects of local and landscape spatial environmental heterogeneity on ant community structure in temperate seminatural upland grasslands of Central Germany. We surveyed 33 grassland sites representing a gradient in elevation and landscape composition. Local environmental heterogeneity was measured in terms of variability of temperature and moisture within and between grasslands sites. Grassland management type (pasture vs. meadows) was additionally included as a local environmental heterogeneity measure. The complexity of habitat types in the surroundings of grassland sites was used as a measure of landscape environmental heterogeneity. As descriptors of ant community structure, we considered species composition in terms of nest density, community evenness, and functional response traits. We found that extensively grazed pastures and within-site heterogeneity in soil moisture at local scale, and a high diversity of land cover types at the landscape scale affected ant species composition by promoting higher nest densities of some species. Ant community evenness was high in wetter grasslands with low within-site variability in soil moisture and surrounded by a less diverse landscape. Fourth-corner models revealed that ant community structure response to environmental heterogeneity was mediated mainly by worker size, colony size, and life history traits related with colony reproduction and foundation. We discuss how within-site local variability in soil moisture and low-intensity grazing promote ant species densities and highlight the role of habitat temperature and humidity affecting community evenness. We hypothesize that a higher diversity of land cover types in a forest-dominated landscape buffers less favorable environmental conditions for ant species establishment and dispersal between grasslands. We conclude that spatial environmental heterogeneity at local and landscape scale plays an important role as deterministic force in filtering ant species and, along with neutral processes (e.g., stochastic colonization), in shaping ant community structure in temperate seminatural upland grasslands.

Density of Axis Deer in Texas: Management Implications for Native White-tailed Deer and Associated Habitats

Abstract Axis deer Axis axis have been widely introduced to new geographic ranges, and in the United States, free-ranging axis deer have become well established in the Edwards Plateau ecoregion as well as other portions of Texas. However, no estimates of axis deer population density nor size have been conducted since 1994. It is hypothesized that axis deer on the Edwards Plateau are potentially competing with native white-tailed deer Odocoileus virginianus for food, space, and habitat resources, and causing damage to important riparian habitats. Our goal was to estimate regional densities of axis deer and white-tailed deer, and provide insight about the potential impacts axis deer may have on native wildlife and their habitats. Estimated using distance sampling techniques in 2018 and 2019, average axis deer density was 19.7 (95% CI: 14.1–25.6) axis deer/km2 compared with 23.0 (95% CI: 18.2–27.5) white-tailed deer/km2, and axis deer densities ranged from 16.9 to 171.0/km2 among eight different land cover types in Kimble County, Texas, with a county-wide estimate of 61,078 (95% CI: 30,407–100,369) axis deer. Axis deer densities were greatest in riparian land cover types, and they selected for two riparian land cover types and upland grasslands. Axis deer population estimates clearly indicate their population size has increased substantially since introduction to Texas in the 1930s. Population management of axis deer is warranted to limit impacts to native wildlife from potential habitat usurpation, or damage to riparian vegetation communities, soil, and water quality.

Distinguishing Saplings of Pines of Piedmont Upland Grassland Systems

The development and assessment of Piedmont upland grassland restoration efforts is hampered in part by continued challenges in identifying immature individuals of three associated pines, Pinus echinata, P. taeda, and P. virginiana, the penultimate of which is thought alien to the system. To help fill this gap, we studied three quantitative and 25 qualitative characters in 174, 2- to 5-year-old saplings in managed stands in Durham County (North Carolina) and 169 herbarium specimens of mature individuals from 94 Piedmont counties from Georgia to Virginia. Although mean short-shoot needle and fascicle sheath lengths differed significantly between lifestage classes of the three species (F8,335=185, p<0.0001 and F8,335=173.5, p<0.0001, respectively), there was substantial range overlap, likely contributing to diagnostic confusion in the field when existing keys are applied. For example, needle length ranges of all lifestage classes of all species overlapped with those of mature P. echinata and 2-year-old P. virginiana. In addition, at the apex of the previous season's growth, 2-year-old saplings of P. echinata and P. virginiana exhibited needles either predominantly or in higher percentages of threes, than the contrasting described preponderance of pairs for mature individuals. Of the 25 qualitative characters evaluated, we found (1) absence of decurrency glaucescence distinguishes 2- to 5-year-old saplings of P. taeda from P. echinata and P. virginiana, and (2) absence of stomatal plugs distinguishes P. virginiana from the others. A diagnostic key to saplings is provided.

Interactive effects of UV radiation and water deficit on production characteristics in upland grassland and their estimation by proximity sensing.

An increase in extreme weather and changes in other conditions associated with ongoing climate change are exposing ecosystems to a very wide range of environmental drivers that interact in ways which are not sufficiently understood. Such uncertainties in how ecosystems respond to multifactorial change make it difficult to predict the impacts of environmental change on ecosystems and their functions. Since water deficit (WD) and ultraviolet radiation (UV) trigger similar protective mechanisms in plants, we tested the hypothesis that UV modulates grassland acclimation to WD, mainly through changes in the root/shoot (R/S) ratio, and thus enhances the ability of grassland to acquire water from the soil and hence maintain its productivity. We also tested the potential of spectral reflectance and thermal imaging for monitoring the impacts of WD and UV on grassland production parameters. The experimental plots were manipulated by lamellar shelters allowing precipitation to pass through or to be excluded. The lamellas were either transmitting or blocking the UV. The results show that WD resulted in a significant decrease in aboveground biomass (AB). In contrast, belowground biomass (BB), R/S ratio, and total biomass (TB) increased significantly in response to WD, especially in UV exclusion treatment. UV exposure had a significant effect on AB and BB, but only in the last year of the experiment. The differences in the effect of WD between years show that the effect of precipitation removal is largely influenced by the potential evapotranspiration (PET) in a given year and hence mainly by air temperatures, while the resulting effect on production parameters is best correlated with the water balance given by the difference between precipitation and PET. Canopy temperature and selected spectral reflectance indices showed a significant response to WD and also significant relationships with morphological (AB, R/S) and biochemical (C/N ratio) parameters. In particular, the vegetation indices NDVI and RDVI provided the best correlations of biomass changes caused by WD and thus the highest potential to remotely sense drought effects on terrestrial vegetation.

The effect of 19 years of restoration managements on forage quality and herbage‐soil relationships within improved upland grassland

AbstractRestoration managements based on extensification strategies are commonly used to improve biodiversity on formerly improved grasslands. In this study the long‐term effects of six different restoration management regimes (extensive sheep grazing only, hay cutting only, hay cutting followed by aftermath extensive grazing; each with and without lime application) on forage quality, and soil/herbage/sward characteristics relationships were determined and compared with a conventionally fertilized, limed and extensively grazed control.Restoration managements incorporating cutting resulted in higher forage quality than forage from grazed‐only treatments; the latter featuring only a few forb species and large proportion of ungrazed matured grasses plus dead biomass. Concentrations of crude protein, neutral detergent fibre and K in the herbage were negatively correlated with cover of forbs and total number of plant species, whereas in vitro organic matter digestibility, and concentrations of water‐soluble carbohydrates, Ca, Mg, and Na were correlated positively. In contrast, concentrations of Ca, Mg, and Na were negatively correlated with the total cover of graminoids and dry matter standing biomass. Regardless of management treatment the forage was generally suitable only for sheep or beef cattle feeding. A positive relationship between P and K concentration in the soil and in the herbage was recorded. No effect of previous liming on forage quality was found. Overall, this study found introducing long‐term restoration managements to support biodiversity by postponing the timing of the first defoliation by cutting to mid growing season did not deteriorate forage quality in comparison with continual extensive sheep grazing in improved upland grassland.

Long-term effects of sheep-grazing and its removal on vegetation dynamics of British upland grasslands and moorlands; local management cannot overcome large-scale trends

The upland and mountainous regions of northern Europe provide a wide variety of ecosystem services. However, these ecosystem services are highly vulnerable to environmental and land-use change. To ensure their future conservation, it is therefore, essential to understand whether upland plant communities will respond positively or negatively to a range of environmental factors such as grazing pressure and landscape-scale factors such as changes in atmospheric SO2 and NOx deposition. To understand this, here, we describe the long-term trends in four UK upland communities (high-level grassland, intermediate grassland, blanket bog, high-level bog) using four replicated long-term experiments examining the effects of sheep grazing compared to no-sheep grazing in Moor House (from 1954 to 2016). Our results showed that species richness and abundance recovered in grazed plots after 2000, with improvements in species richness and abundance of vascular plants, mosses, and liverworts. Unfortunately, no improvement was found for lichens. Species richness, vascular plants, and mosses recovered the fastest, and much faster than liverworts. There was no evidence of slower recovery of species richness and abundance in plots where sheep grazing was removed. These results are consistent with longitudinal studies suggesting recovery after 2000 as a result of reduced atmospheric deposition. Although trends in diversity and abundance in the grazed and ungrazed plots were not identical, they were not markedly different either. The similar richness and abundance trends in the grazed and ungrazed plots found in each plant community suggest that within-community dynamics may overcome initial differences between the grazing treatments over time. In contrast, differences in richness and abundance among plant communities over time suggest that some landscape-scale trends, such as those caused by a reduction in nutrient inputs, initiate community-dependent recovery.

Agri-environment schemes are associated with greater terrestrial invertebrate abundance and richness in upland grasslands

Agri-environment schemes are a key mechanism by which agricultural sustainability is encouraged by subsidising farmers to adopt environmentally friendly management (e.g. reduction of inputs) to maintain and enhance the delivery of biodiversity-associated ecosystem services. Studies testing the efficacy of agri-environment schemes have yielded varying results, and few have focused on upland (marginal or Less Favoured Area) grassland (> 150 m above sea level) where productivity is poor. This study used a factorial field experiment to examine patterns in plant communities and terrestrial invertebrates between agri-environment scheme and conventionally managed semi-improved and improved upland grasslands, using 90 spatially paired fields. Total plant species richness and rare plant species richness (those with < 10% occurrence) were unaffected by agri-environment scheme management, but were significantly higher on semi-improved than improved grasslands. Total and rare invertebrate abundance and family-level richness were unrelated to grassland type (semi-improved or improved). Total and rare invertebrate abundances were 4% and 218% higher, and total and rare invertebrate family-level richness were 17% and 14% higher in agri-environment scheme than conventionally managed fields, respectively. Here, we show that agri-environment scheme management of marginal or Less Favoured Area upland grassland was associated with higher multi-taxa invertebrate abundance and richness associated with swards indicative of wetter conditions with lower dominance of perennial ryegrass (Lolium perenne) and greater coverage of other native grass species compared to conventional management. This suggests that agri-environment schemes may maintain, enhance or offset declines in terrestrial invertebrates and their associated ecosystem service delivery by maintaining more diverse swards, and suggests that they make a positive contribution to biodiversity conservation.

Taxonomic and functional structure of aquatic insect assemblages in headwaters from upland grasslands (Córdoba, Argentina)

Taxonomic and functional structure of aquatic insect assemblages in headwaters from upland grasslands (Córdoba, Argentina)

A theoretically-based overland flow resistance law for upland grassland habitats

Sediments conveyed from interrill areas to rills are transported by a thin flow (overland flow) and the knowledge of overland flow resistance is useful to evaluate overland flow velocity and sediment transport capacity.The aim of this paper was to verify the applicability of a theoretical overland flow resistance law, based on a power-velocity distribution, using field measurements for four upland grassland types used in different management strategies (Hay Meadows, Low-density Grazing, Rushes and Rank Grassland). Particular attention was deserved to the effects of vegetation growth cycles on the surface roughness and the corresponding reduction of overland flow velocity.The relationship between the parameter Γ of the power velocity profile, the flow Froude number and the Reynolds number, obtained by dimensional analysis, was calibrated using the available data. A specific calibration for each upland grassland type and taking into account the temporal phases of the vegetation growth was also carried out.The theoretical approach, checked by the available field measurements, allowed to establish that a) the proposed theoretical flow resistance law, which considers also the effect of the flow Reynolds number, allows an accurate estimate of the Darcy–Weisbach friction factor, b) the theoretical overland flow resistance law considers the temporal variability of vegetation characteristics, c) this flow resistance law can be specifically calibrated for taking into account for each upland grassland type the effect of the vegetation temporal variability and d) a low effect of the seasonal variation of roughness in grassland environments is detected.The interrill soil erosion processes are strongly related to hillslope hydraulics and the proposed overland flow resistance law is useful to model soil erosion processes.

Grazing Effects on the Composition, Diversity, and Function of Wet Meadow Grasslands in Manitoba, Canada

Wet grasslands are an important element of rangeland communities around the world and are key in the provision of many ecosystem services, including interception of runoff, filtration of pollutants, storage of carbon, and maintenance of wildlife habitat. In the northern Great Plains, wet grasslands are often more productive than upland grasslands and are an important source of seasonal forage or hay. As climates continue to limit growing conditions and yields of upland forages, grazing pressure on wet grasslands may increase. Our research focused on a wet meadow rangeland in Manitoba, Canada to test how the timing and intensity of grazing affect the composition, diversity, and function of plants and soils. Our results demonstrate that the effects of grazing on wet meadow grasslands depend on its timing and intensity. Early grazing shifted the composition of plants, increasing the abundance of weedy and invasive species, including foxtail barley (Hordeum jubatum). The effect of grazing on plant diversity also depended on its intensity. As a result, the spatial heterogeneity of wet grasslands increased following early, intense grazing but decreased following late-season grazing. Although the effect of grazing on a number of soil variables did not differ among grazing treatments, early, intense grazing increased soil bulk density. Our results demonstrate that late-season, moderate-intensity grazing can sustain the diversity and function of wet meadow grasslands. Our research also highlights the negative impacts of early-season, intense grazing on the proliferation of weedy and invasive plants. As changing climates across the Great Plains continue to increase grazing pressure on marginal rangelands, adaptive management must focus on increasing the resilience of wet grasslands. Our work points to an important gap in our understanding of interactions among grazing, ecosystem services, and belowground production in wet meadow grasslands.

Aerial invertebrate functional groups respond to landscape composition with only detritivores and predators responding to agri-environment scheme management

Landscape-scale agricultural intensification is a major driver of biodiversity loss. Highly mobile species, such as aerial invertebrates may be disproportionately affected by land cover at large spatial scales due to their ability to disperse. Assessing the efficacy of environmentally friendly farming, such as Agri-Environment Schemes (AES), therefore, requires establishing the influence of land cover beyond focal farms or fields, contextualising the impact of agricultural management. This study measured the response of aerial invertebrate functional groups to AES management in improved and semi-improved upland grasslands accounting for spatial autocorrelation and multi-scale effects of land cover within buffers varying from 100 m to 5 km at 88 paired fields. Total aerial invertebrate abundance and diversity, including detritivores, herbivores, nectivores, predators and parasitoids all responded to different land cover types at varying scales indicative of highly complex and idiosyncratic functional group responses to landscape.After accounting for spatial autocorrelation and multi-scale landscape composition, total aerial invertebrate abundance was unaffected by agricultural management but diversity was (5%) higher in AES than conventionally managed fields. Detritivore (mostly Mycetophilidae fungus gnat) diversity and abundance were higher in AES than conventional fields, but only on improved grasslands, while predator (adult Muscidae house fly, Scathophagidae dung fly and Dolichopodidae long-legged fly) diversity was lower but abundance higher in AES than conventional fields. Aerial invertebrate herbivores (Anthomyiidae root-maggot flies and Cecidomyiidae gall midges and gnats), nectivores (Syrphidae hoverflies and Apoidea bees) and parasitoids (Ichneumonidae wasps) responded to landscape composition, but not agricultural management. Synthesis and Applications: this study suggests that landscape composition drives aerial invertebrate functional group diversity and abundance at multiple spatial scales. Nevertheless, the responses of some functional groups (detritivores and predators) to local agricultural management suggest that AES management may contribute to the maintenance or enhancement of ecosystem service delivery (nutrient cycling and pest biocontrol). Explicitly accounting for multi-scale landscape effects is necessary when assessing the impact of agricultural management on highly mobile taxa.