A high proportion of regional plant biodiversity occurs in hotspots of species richness that cover small areas created and maintained by disturbance. Sustaining plant diversity in these areas ...requires region‐ and habitat‐specific management of disturbance and, increasingly, habitat expansion or restoration to offset species losses. Coastal sandplain grasslands are threatened, disturbance‐controlled plant biodiversity hotspots in the northeastern United States. We formed a network of grassland managers and scientists to review the published and unpublished sandplain grassland literature. Additionally, we conducted interviews with grassland managers about management challenges and successes. Principal concerns of managers were increases in woody plant cover, losses of rare species, increased cover and variety of invasive species, and constraints on the ability to use prescribed fire. The literature review and managers' experiences together led to the following recommendations: (1) increase applications of prescribed burning and mowing during the growing season when possible; (2) expand selective removal of woody plants including herbicide use; (3) test the application of harrowing or disking to reduce woody plant density especially in places where invasive plant densities are low; and (4) increase applications of combinations of disturbances in rotations with occasional fire. At regional scales, monitoring of management effects, identification of parcels for potential grassland expansion and restoration, and increased supplies of native seeds of plant ecotypes to use for restoration ahead of climate change are badly needed. Formation of networks of managers and scientists to share information and experiences has the potential to greatly improve land management within other biodiversity hotspots.
•Curlew, redshank, godwit, lapwing prefer moderately wet and flooded grasslands.•Waders avoid buildings, drainage canals and single trees.•Presence of corvids increases detectability of meadow ...waders.•Open and wet grasslands are recommended for wader conservation.
Populations of meadow waders have shown steep declines in Europe during recent decades. However, empirical evidence concerning habitat preferences of different species in east Europe is largely lacking. In this study we investigate occurrence of the Eurasian curlew (Numenius arquata), black-tailed godwit (Limosa limosa), common redshank (Tringa totanus) and northern lapwing (Vanellus vanellus) in 413 grassland plots (c. 50,000ha in total) located in Polish lowland surveyed three times during spring of 2015 and 2016. Using hierarchical occupancy models corrected for imperfect detection we link local water conditions, forest cover and scattered trees and presence of cows and buildings with occurrence of waders. Presence of godwit positively correlated with flooding and wetness while negatively with drainage ditches and single trees. Redshank was positively associated with flooding and negatively with ditches and proximity to buildings. Lapwing was less often observed in proximity to buildings and at sites with numerous trees whereas curlews, showed no clear associations with any of the environmental variables investigated. Detectability of studied species (except godwit) was higher when corvids were present suggesting that species interactions may affect detection. Field survey conditions (e.g. time of day, number of visit) also contributed to detectability of all studied species. Our study suggest that water availability, including natural flooding, increases habitat quality for breeding waders, while single trees and farm buildings may reduce grassland availability for these species. Thus waders-oriented agri-environment subsidies, besides adjusting grassland management to breeding phenology, should also focus on wetness and openness of grasslands.
1. Wetland ecosystems throughout the world are threatened by drainage and intensification of agriculture. Consequently, many wetland species of conservation concern are now restricted to fewer and ...smaller sites, and maintaining these species often requires intensive habitat management. 2. In Western Europe, breeding wader populations have declined severely as a result of wetland degradation, but very high levels of prédation on eggs and chicks are now preventing population recovery. Wet grassland management for breeding waders has focussed on providing suitable nesting habitats, but the potential for management of landscape features to influence prédation rates remains largely unknown. 3. Using a 7-year study of breeding lapwing Vanellus vanellus and redshank Tringa totanus we first identify features that influence nest predation, and then use this information to compare the magnitude of change in nest predation rates that could potentially result from future landscape management scenarios. 4. As lapwing nest predation rates are higher (i) in fields further from patches of tall vegetation, (ii) close (<50 m) to field edges in wet fields, (iii) further from field edges in dry fields and (iv) in areas of low lapwing nesting density, we modelled a series of realistic scenarios in which the area of tall vegetation and the extent and distribution of surface water were varied across the reserve, to quantify the magnitude of change in nest predation rate that could potentially have been achieved through management. 5. Modelled scenarios of changes in surface water and area of tall vegetation indicated that reduced surface flooding combined with removal of tall vegetation could result in significant increases in lapwing nest predation rates in areas with low nesting densities and nests in field centres. By contrast, a ~20% reduction in nest prédation, corresponding to -100 more chicks hatching per year, is predicted in scenarios with expansion of tall vegetation in areas with high lapwing nest density and nests close to field edges. 6. Synthesis and applications. These management scenarios suggest that, for breeding waders in wet grassland landscapes, creating areas of tall vegetation and concentrating surface flooding (to encourage high nesting densities and influence nesting distribution) can potentially help to reduce the unsustainably high levels of nest prédation that are preventing population recovery.
Species may benefit from green infrastructure, i.e. the network of natural and anthropogenic habitat remnants in human‐dominated landscapes, if it helps isolated populations in remaining habitat ...patches to be functionally connected. The importance of green infrastructure is therefore increasingly emphasized in conservation policy to counter biodiversity loss. However, there is limited evidence, particularly in plants, that green infrastructure promotes functional connectivity, i.e. supports the colonization of habitat patches across a landscape. We applied landscape genetics to test whether the green infrastructure supports structural and functional connectivity in the grassland perennial Galium verum, in 35 landscapes in Belgium, Germany and Sweden. We used multivariate genetic clustering techniques, nestedness analyses and conditional inference trees to examine landscape‐scale patterns in genetic diversity and structure of plant populations in the green infrastructure surrounding semi‐natural grasslands. Inferred functional connectivity explained genetic variation better than structural connectivity, yielding positive effects on genetic variation. The road verge network, a major structural component of the green infrastructure and its functional connectivity, most effectively explained genetic diversity and composition in G. verum. Galium verum ramets occupying the surrounding landscape proved to be genetic subsets of focal grassland populations, shaping a nested landscape population genetic structure with focal grasslands, particularly ancient ones, harbouring unique genetic diversity. This nested pattern weakened as road network density increased, suggesting road verge networks enable high landscape occupancy by increased habitat availability and facilitates gene flow into the surrounding landscape. Our study proposes that green infrastructure can promote functional connectivity, providing that a plant species can survive outside of core habitat patches. As this often excludes habitat specialist species, conservation practice and policy should primarily focus on ancient, managed semi‐natural grasslands. These grasslands both harbour unique genetic diversity and act as primary gene and propagule sources for the surrounding landscape, highlighting their conservation value.
Understanding patterns of seed predation in tallgrass prairie restorations is vital because seed additions are often used by managers to increase diversity and promote native species. However, the ...success of seed additions depends on the extent of seed predation. It is not clear how seed predation varies through time and to what extent it is affected by various commonly used management techniques in grasslands (e.g. spring or fall prescribed burns, mowing). We examined how predation of Sorghastrum nutans seeds changed during eight trials between June 2018 and April 2019 in plots that received one of four different plant litter removal treatments (fall mow, fall burn, spring burn, and unaltered control). Granivory varied throughout the year, reaching its peak in the late fall and early winter. However, we found that seed predators consumed significantly fewer seeds when litter was removed following fall burn and fall mow treatment applications. These treatments occurred during times when granivory was otherwise high in areas where litter remained intact (control and spring burn plots). Our findings highlight the importance of management decisions and how they interact with granivory in grassland restorations. Both time of year and litter cover determine seed predation rates; seed predators consume more seeds when seeds are abundant but rely on intact litter cover while foraging. This suggests that if seeds are added during the fall, litter should be removed to minimize the loss of seeds to granivory. Alternatively, seed additions during the spring are likely to experience lower rates of seed predation.
Grassland ecosystems play an essential role in climate regulation through carbon (C) storage in plant and soil. But, anthropogenic practices such as livestock grazing, grazing related excreta ...nitrogen (N) deposition, and manure/fertilizer N application have the potential to reduce the effectiveness of grassland C sink through increased nitrous oxide (N2O) and methane (CH4) emissions. Although the effect of anthropogenic activities on net greenhouse gas (GHG) fluxes in grassland ecosystems have been investigated at local to regional scales, estimates of net GHG balance at the global scale remains uncertain. With the data-model framework integrating empirical estimates of livestock CH4 emissions with process-based modeling estimates of land CO2, N2O and CH4 fluxes, we examined the overall global warming potential (GWP) of grassland ecosystems during 1961-2010. We then quantified the grassland-specific and regional variations to identify hotspots of GHG fluxes. Our results show that, over a 100-year time horizon, grassland ecosystems sequestered a cumulative total of 113.9 Pg CO2-eq in plant and soil, but then released 91.9 Pg CO2-eq to the atmosphere, offsetting 81% of the net CO2 sink. We also found large grassland-specific variations in net GHG fluxes, with pasturelands acting as a small GHG source of 1.52 ± 143 Tg CO2-eq yr−1 (mean ± 1.0 s.d.) and rangelands a strong GHG sink (−442 ± 266 Tg CO2-eq yr−1) during 1961-2010. Regionally, Europe acted as a GHG source of 23 ± 10 Tg CO2-eq yr−1, while other regions (i.e. Africa, Southern Asia) were strong GHG sinks during 2001-2010. Our study highlights the importance of considering regional and grassland-specific differences in GHG fluxes for guiding future management and climate mitigation strategies in global grasslands.
The long-term estimation of grassland aboveground biomass (AGB) is important for grassland resource management in the Three-River Headwaters Region (TRHR) of China. Due to the lack of reliable ...grassland AGB datasets since the 1980s, the long-term spatiotemporal variation in grassland AGB in the TRHR remains unclear. In this study, we estimated AGB in the grassland of 209,897 km2 using advanced very high resolution radiometer (AVHRR), MODerate-resolution Imaging Spectroradiometer (MODIS), meteorological, ancillary data during 1982–2018, and 75 AGB ground observations in the growth period of 2009 in the TRHR. To enhance the spatial representativeness of ground observations, we firstly upscaled the grassland AGB using a gradient boosting regression tree (GBRT) model from ground observations to a 1 km spatial resolution via MODIS normalized difference vegetation index (NDVI), meteorological and ancillary data, and the model produced validation results with a coefficient of determination (R2) equal to 0.76, a relative mean square error (RMSE) equal to 88.8 g C m−2, and a bias equal to −1.6 g C m−2 between the ground-observed and MODIS-derived upscaled AGB. Then, we upscaled grassland AGB using the same model from a 1 km to 5 km spatial resolution via AVHRR NDVI and the same data as previously mentioned with the validation accuracy (R2 = 0.74, RMSE = 57.8 g C m−2, and bias = −0.1 g C m−2) between the MODIS-derived reference and AVHRR-derived upscaled AGB. The annual trend of grassland AGB in the TRHR increased by 0.37 g C m−2 (p < 0.05) on average per year during 1982–2018, which was mainly caused by vegetation greening and increased precipitation. This study provided reliable long-term (1982–2018) grassland AGB datasets to monitor the spatiotemporal variation in grassland AGB in the TRHR.
Monitoring grazing activities on grassland is crucial for ensuring sustainable grassland development and for protecting it from grazing-led degradation. The Leaf Area Index (LAI), which measures leaf ...coverage over a surface area, is commonly used as a proxy for grassland condition. However, current studies focus on the year-round or seasonal aggregated LAI change rather than the change that can be attributed explicitly to grazing, which is the important indicator for quantifying grassland grazing. This paper presents a new exponential growth function under grazing with an estimation algorithm, the purpose of which is to extract grazing-led LAI changes for every 8 days' satellite observations. All the analyses are based on the Moderate Resolution Imaging Spectroradiometer (MODIS) MOD15A2H products. An improved MODIS LAI and an expected LAI are produced separately, considering both current and previous grazing-led LAI changes. The differences between expected LAI and improved LAI are then converted to the equivalent carbon mass of grazed material. This grazed carbon mass is then aggregated within the growing season, and compared with the expected carbon mass consumed by livestock (calculated from statistics yearbooks). In addition, Net Primary Productivity (NPP) is produced using the improved LAI, simulated by a Light Use Efficiency with Vegetation Photosynthesis Model (LUE-VPM). This is compared with the NPP produced by LUE-VPM based on original MODIS LAI, MODIS NPP products (MOD17A2H) and grassland monitoring stations' in situ measured data. Results show that the NPP calculated from the improved LAI is statistically the same as in situ converted NPP with a p-value equalling 0.998 (the RMSE between the two is 97.77 gC/m2). Conversely, the p-value between converted in situ measured carbon mass and the MODIS NPP product is 0.011 (the RMSE between the two is 133.98 gC/m2), indicating they are statistically different. The results detailed in this paper provide precise and almost real-time grassland grazing monitoring information for policy makers managing grassland.
•We use a new growth function to improve the MODIS LAI products.•Per-pixel grazing-led LAI changes are identified based on MOIDS LAI products.•Our improved LAI performs better than the MODIS LAI in NPP calculation.•NPP of grazing-led LAI changes matches with livestock consumption.•This method improves the estimation of grassland grazing with remote sensing data.
Marsh horsetail (
L.) is one of the most poisonous plants of wet grasslands in the northern hemisphere, which poses a major health threat to livestock. Available data on the levels of its main ...alkaloids are currently contradictory due to the inadequate analytical methods and the wide variation in toxicity levels reported. Here, we tested the hypothesis that the ontogenetic stage of plant development may explain a significant part of the variations in the main
-type alkaloids. Two populations of marsh horsetail were sampled over two growing seasons. The plant material was classified according to their developmental stages and subsequently the main alkaloids were determined by hydrophilic interaction liquid chromatography and high-performance liquid chromatography electrospray tandem mass spectrometry (HILIC HPLC-ESI-MS/MS) analysis. ANOVA revealed significant effects of the ontogenetic stage but not the site on the main
-type alkaloids (sum of palustrine and palustridiene) ranging from 213 to 994 mg/kg dry matter (DM). The highest alkaloid content was found in the stages of early development. Not the season itself, but the growth temperature co-influenced the alkaloid content. Our results help to resolve the seemingly contradictory information provided by previous studies on the toxicity of
and are of practical relevance for the prevention of contamination risks in wet grassland use.
Land‐use and land‐cover change associated with agriculture is one of the main drivers of biodiversity loss. In heavily modified agricultural landscapes, grazing lands may be the only areas that can ...provide essential resources for native grassland species. Management decisions, such as choice of livestock species, affect the extent to which grazing lands provide suitable habitat for native species such as pollinators.
Our study compared how sheep versus cattle herbivory affected floral resources and butterfly abundance across low‐diversity, former Conservation Reserve Program (CRP) pastures managed with patch‐burn grazing.
Across all years (2017–2019), flowering species richness and abundance were significantly higher in cattle pastures than sheep pastures. On average, we recorded 6.9 flowering species/transect in cattle pastures and 3.8 flowering species/transect in sheep pastures. The average floral abundance per transect was 1278 stems/transect in cattle pastures and 116 stems/transect in pastures grazed by sheep.
Similarly, we observed higher butterfly species richness, diversity, and abundance in cattle than in sheep pastures. In cattle pastures, we observed an average of 75 butterflies and 6.75 species per transect, compared with an average of 52 butterflies and 3.37 species per transect in sheep pastures. However, the butterfly community composition did not significantly differ between grazing treatments likely because agricultural‐tolerant, habitat generalists comprised the majority of the butterfly community. Five generalist butterflies comprised 92.3% of observations; Colias philodice was the most abundant (61% of observations). Speyeria idalia and Danaus plexippus, two butterflies of conservation concern, comprised less than 0.5% of butterfly observations.
Our results, which are among the first attempt quantifying butterfly use of post‐CRP fields grazed by livestock, show that increased precipitation and cattle grazing promoted higher forb abundance and richness. However, additional interventions may be needed to enhance floral resources to sustain and improve pollinator diversity in these landscapes.
Sheep grazing resulted in significantly lower floral abundance compared with cattle grazing. However, butterfly communities were fairly homogenous and did not differ between grazers.
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