Land-use intensification is a major driver of biodiversity loss. However, understanding how different components of land use drive biodiversity loss requires the investigation of multiple trophic ...levels across spatial scales. Using data from 150 agricultural grasslands in central Europe, we assess the influence of multiple components of local- and landscape-level land use on more than 4,000 above- and belowground taxa, spanning 20 trophic groups. Plot-level land-use intensity is strongly and negatively associated with aboveground trophic groups, but positively or not associated with belowground trophic groups. Meanwhile, both above- and belowground trophic groups respond to landscape-level land use, but to different drivers: aboveground diversity of grasslands is promoted by diverse surrounding land-cover, while belowground diversity is positively related to a high permanent forest cover in the surrounding landscape. These results highlight a role of landscape-level land use in shaping belowground communities, and suggest that revised agroecosystem management strategies are needed to conserve whole-ecosystem biodiversity.
Climate change and anthropogenic disturbances have threatened the ecosystem functions including ecological, production and livelihood functions (EPLFs) of the alpine grassland on the Qinghai-Tibet ...Plateau (QTP). Integrating the trade-offs and synergies among the EPLFs into the regional development decision-making system is important for achieving sustainable development goals on the QTP. This study constructed an ecological-production-livelihood functions (EPLFs) index system to quantify and compare the functions of various cooperative and individual management grasslands. A comprehensive functions index (CFI), a total functions value (TF) and a trade-off index (TOI) were built to evaluate these two types of grasslands. The results indicated that production function (PF) of cooperative management grasslands were significantly higher and lower than those of individual management grasslands due to higher productive fixed assets of cooperative management grasslands. By contrast, ecological and livelihood function of cooperative and individual management grasslands did not show significant difference. In addition, the correlation between PF and CFI was also higher in cooperative management grasslands than individual management grasslands. The SEM analysis revealed that the ecological and production functions have positive direct effects on TF. Furthermore, the PF have negative direct effects on TOI. The cooperative management grasslands with higher PF can reduce TOI and enhance TF, and in turn increase the CFI, compared with individual management grasslands. The improvement of PF is critical for enhancing overall EPLFs and decreasing the trade-off of EPLFs. Therefore, we recommend that policymakers attach importance to the multi-objective optimization potential offered by cooperative management grasslands, and provide corresponding policy support to decrease trade-offs and increase synergies of EPLFs on the QTP.
•Cooperative management model has positive effects on productions functions and reducing trade-off intensity.•The productive fixed assets are the key indicator in production function.•The high production function of grassland can directly affect the total functions and reduce the trade-offs.
ABSTRACT
A European transect was established, ranging from Sweden to the Azores, to determine the relative influence of geographic factors and agricultural small-scale management on the grassland ...soil microbiome. Within each of five countries (factor ‘Country’), which maximized a range of geographic factors, two differing growth condition regions (factor ‘GCR’) were selected: a favorable region with conditions allowing for high plant biomass production and a contrasting less favorable region with a markedly lower potential. Within each region, grasslands of contrasting management intensities (factor ‘MI’) were defined: intensive and extensive, from which soil samples were collected. Across the transect, ‘MI’ was a strong differentiator of fungal community structure, having a comparable effect to continental scale geographic factors (‘Country’). ‘MI’ was also a highly significant driver of bacterial community structure, but ‘Country’ was clearly the stronger driver. For both, ‘GCR’ was the weakest driver. Also at the regional level, strong effects of MI occurred on various measures of the soil microbiome (i.e. OTU richness, management-associated indicator OTUs), though the effects were largely regional-specific. Our results illustrate the decisive influence of grassland MI on soil microbial community structure, over both regional and continental scales, and, thus, highlight the importance of preserving rare extensive grasslands.
Across a European transect, comprising five countries, we did show that small-scale agricultural grassland management can affect soil fungal community structure as much as continental scale geographic patterns.
Grasslands absorb and release carbon dioxide (CO
), emit methane (CH
) from grazing livestock, and emit nitrous oxide (N
O) from soils. Little is known about how the fluxes of these three greenhouse ...gases, from managed and natural grasslands worldwide, have contributed to past climate change, or the roles of managed pastures versus natural grasslands. Here, global trends and regional patterns of the full greenhouse gas balance of grasslands are estimated for the period 1750 to 2012. A new spatially explicit land surface model is applied, to separate the direct effects of human activities from land management and the indirect effects from climate change, increasing CO
and regional changes in nitrogen deposition. Direct human management activities are simulated to have caused grasslands to switch from a sink to a source of greenhouse gas, because of increased livestock numbers and accelerated conversion of natural lands to pasture. However, climate change drivers contributed a net carbon sink in soil organic matter, mainly from the increased productivity of grasslands due to increased CO
and nitrogen deposition. The net radiative forcing of all grasslands is currently close to neutral, but has been increasing since the 1960s. Here, we show that the net global climate warming caused by managed grassland cancels the net climate cooling from carbon sinks in sparsely grazed and natural grasslands. In the face of future climate change and increased demand for livestock products, these findings highlight the need to use sustainable management to preserve and enhance soil carbon storage in grasslands and to reduce greenhouse gas emissions from managed grasslands.
The economic management of lignocellulosic biomass from semi-natural grasslands is now a challenge across Europe. The abandonment of mowing these grasslands leads to the gradual degradation of these ...ecosystems. This study investigates how chemical and biological factors affect the suitability of biomass from abandoned grasslands for biogas production. We sampled 30 mown and 30 abandoned grassland sites in the Sudetes Mountains (Poland and Czechia). The cover contribution of short herbs was found to be significantly higher in mown grasslands (p < 0.001), while that of tall herbs was more prevalent in abandoned grasslands (p < 0.01). The specific biogas yield (SBY, NL kg−1 volatile solids) is negatively affected by an increased percentage of herbs in the biomass of mown and abandoned grasslands. This is due to the inhibitory effect of herbs on biodegradation, the increase in lignin content and the decrease in cellulose. This study highlights the importance of individual plant species in assessing grassland biomass for area biogas yield (ABY, m3 ha−1) and provides new insights into a field that has not yet been extensively investigated. In mown grasslands, ABY was most positively correlated with grass species (Arrhenatherum elatius, Trisetum flavescens and Festuca pratensis). In abandoned grasslands, the ABY was most correlated with herbaceous species (Galium aparine, Urtica dioica and Chaerophyllum aromaticum) and grasses (A. elatius and Elymus repens). Mown grasslands had significantly higher species richness (p < 0.001) compared to abandoned grasslands, but the number of species sampled did not correlate with SBY and ABY. This study contributes to the development of a sustainable bio-economy by highlighting the need for efficient use of grassland biomass. This approach helps protect semi-natural ecosystems and facilitates sustainable management of renewable resources.
•Certain grassland plant species significantly impact area biogas yield.•Species richness has no negative effect on specific and area biogas yield.•Grassland management maintains an appropriate ratio of herbs to grasses.•Biogas production from hay can help restore abandoned grassland.
We expand the concept of "old growth" to encompass the distinct ecologies and conservation values of the world's ancient grass-dominated biomes. Biologically rich grasslands, savannas, and ...open-canopy woodlands suffer from an image problem among scientists, policy makers, land managers, and the general public, that fosters alarming rates of ecosystem destruction and degradation. These biomes have for too long been misrepresented as the result of deforestation followed by arrested succession. We now know that grassy biomes originated millions of years ago, long before humans began deforesting. We present a consensus view from diverse geographic regions on the ecological characteristics needed to identify old-growth grasslands and to distinguish them from recently formed anthropogenic vegetation. If widely adopted, the old-growth grassland concept has the potential to improve scientific understanding, conservation policies, and ecosystem management.
Effective and accurate monitoring of grassland above-ground biomass (AGB) is important for pastoral agriculture planning and management. In this study, we combined 1433 AGB field measurements and ...remotely sensed data with the goal of establishing a suitable model for estimating grassland AGB in the Three-River Headwaters Region (TRHR) of China, which is one of the most sensitive regions to the warming climate. A back-propagation artificial neural network (BP ANN) was used to select the variables that contribute the most to the model's estimation of AGB, and then we built the model. Out of 13 variables, 5 variables were selected to build the BP ANN model, and we used cross validation for the accuracy assessment. The results show that: (1) the modeled mean AGB (2001–2016) provides a reasonable spatial distribution that is similar to the field measurements but reveals more details and has better spatial coverage than the limited field measurements are able to provide; (2) the overall trend of AGB in the TRHR is increasing more than decreasing (44.4% vs 29.2%, respectively) and has a stable area of 26.4%; and (3) the BP ANN model achieves better results than do the traditional multi-factor regression models (R2: 0.75–0.85 vs 0.40–0.64, RMSE: 355–462 vs 537–689kgDW/ha). This study presents an effective and operational BP ANN model that estimates grassland AGB for the study area with high accuracy at 500m spatial resolution, providing a scientific basis for the determination of reasonable stocking capacity and possible future development.
•NDVI, grass height & cover, longitude and latitude are crucial to the AGB model.•The BP ANN model is much better than the traditional multi-factor regression models.•The overall trend of AGB in the TRHR is increasing more than decreasing (2001–2016).
Grassland is the significant composition of the terrestrial carbon pool. Its belowground carbon turnover process is sensitive to land use changes and has a huge impact on atmospheric CO2 contents. ...However, the interpretation of the vertical distribution of δ13C values of soil organic carbon (SOC-δ13C), the SOC turnover rate (β value) and their changes in the soil profile remain uncertain after fencing (grazing exclusion). Grasslands that have been fenced for 39 years and grazed (as the control) on the Loess Plateau, China were selected to evaluate the vertical distribution of SOC-δ13C and β values and their influencing factors across the 0–100 cm soil profile (0–10, 10–20, 20–40, 40–60, 60–80, 80–100 cm). The results showed that SOC gradually decreased but SOC-δ13C overall increased with soil depths. Fencing significantly decreased the SOC-δ13C in 10–80 cm depth. The SOC-δ13C had a positive correlation with δ13C values of microbial biomass carbon (MBC-δ13C), but negative correlations with root biomass. Besides, the β values of 0–60 cm depth were higher in fencing grasslands (−2.70) than that in grazing grasslands (−11.38). Overall, carbon input, microbial fractionation and soil leaching contributed to the increasing trend of SOC-δ13C with soil depths, and fencing increased the SOC content in the profile but decreased the SOC turnover rate in 0–60 cm soils. The results provide direct evidence for the change of SOC-δ13C and a more comprehensive understanding of SOC-δ13C and SOC turnover dynamics with long-term fencing across the soil profile. The information on SOC dynamics and their feedback to long-term fencing can aid in developing reasonable grassland management measures.
•SOC gradually decreased but SOC-δ13C overall increased with soil depths.•Grazing exclusion increased soil C contents but decreased the C turnover rate.•SOC-δ13C was positively correlated with δ13C values of microbial biomass carbon.•SOC-δ13C in grazing grasslands was affected by pH, cPOC, C/N and enzyme activity.•SOC-δ13C in fencing grasslands was affected by C/N.
•Phosphorus input into croplands is expected to increase 51–86% by the year 2050.•In developed and transition regions, legacy phosphorus attenuates the increasing need for fertilizer.•Developing ...regions will likely continue to increase fertilizer use to meet the growing agricultural demand.
A spatially explicit, two-pool soil phosphorus (P) model was used to analyze cropland P dynamics and fertilizer demand based on future crop production as projected in the shared socioeconomic pathways (SSPs). The model was initialized with historical data on P inputs and uptake, which governed the soil P accumulation up to present day. In contrast to existing scenario studies, the model accounts for both soil characteristics relevant to P retention and changing land use. At the global scale, crop uptake and the fraction of the applied P fertilizer that is directly taken up by plant roots govern the P quantities present in the soil. Despite the differences in the storylines among the SSPs, the quantitative implementation results in estimates for crop production and P inputs that are quite similar, which contrasts with the stark divergence in terms of population and incomes. In addition to global fertilizer P inputs in croplands increasing from 14.5 Tg P yr−1 in 2005 to 22–27 Tg P yr−1 in 2050, this study also estimates that 4–12 Tg P yr−1 would be needed in 2050 in global intensively managed grasslands to maintain fertility. Our new model approach can pinpoint the contribution of area expansion and crop yield improvement toward the total production, whereby the latter is shown to contribute 100% to 69%, depending on the scenario.
ABSTRACT
Despite growing recognition of the conservation values of grassy biomes, our understanding of how to maintain and restore biodiverse tropical grasslands (including savannas and open‐canopy ...grassy woodlands) remains limited. To incorporate grasslands into large‐scale restoration efforts, we synthesised existing ecological knowledge of tropical grassland resilience and approaches to plant community restoration. Tropical grassland plant communities are resilient to, and often dependent on, the endogenous disturbances with which they evolved – frequent fires and native megafaunal herbivory. In stark contrast, tropical grasslands are extremely vulnerable to human‐caused exogenous disturbances, particularly those that alter soils and destroy belowground biomass (e.g. tillage agriculture, surface mining); tropical grassland restoration after severe soil disturbances is expensive and rarely achieves management targets. Where grasslands have been degraded by altered disturbance regimes (e.g. fire exclusion), exotic plant invasions, or afforestation, restoration efforts can recreate vegetation structure (i.e. historical tree density and herbaceous ground cover), but species‐diverse plant communities, including endemic species, are slow to recover. Complicating plant‐community restoration efforts, many tropical grassland species, particularly those that invest in underground storage organs, are difficult to propagate and re‐establish. To guide restoration decisions, we draw on the old‐growth grassland concept, the novel ecosystem concept, and theory regarding tree cover along resource gradients in savannas to propose a conceptual framework that classifies tropical grasslands into three broad ecosystem states. These states are: (1) old‐growth grasslands (i.e. ancient, biodiverse grassy ecosystems), where management should focus on the maintenance of disturbance regimes; (2) hybrid grasslands, where restoration should emphasise a return towards the old‐growth state; and (3) novel ecosystems, where the magnitude of environmental change (i.e. a shift to an alternative ecosystem state) or the socioecological context preclude a return to historical conditions.
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