Grassland Productivity Research Articles

Climate Change and Human Activities: Their Roles in Shaping Land Productivity in Northern Nigeria

ABSTRACTThe Northern Nigeria Region (NNR) has historically suffered from land productivity changes due to anthropogenic and climatic factors. The development of methodologies that can evaluate these changes at the pixel level and spatialize the effects of driving factors is a key requisite to provide targeted solutions for land degradation, in a country with population growth and desert advancement. In this study, we applied MODIS series data to assess land productivity changes in the NNR (2001–2021) using NDVI trend analysis. We also used correlation and RESTREND analyses to discriminate between climate and human factors and map their effects. The results indicated that approximately 30.7% of the NNR showed land degradation, whereas 27.1% showed an increase in land productivity. There was a clear spatial pattern, with increasing productivity closer to the northern Nigeria boundary with Niger, and decreasing productivity concentrated in the central and southern parts of the NNR. Anthropogenic factors had a greater impact on land degradation and improvement, compared with rainfall. The climate forcing contributed most to land productivity in the northeastern part of the NNR. Land degradation is mainly associated with overgrazing and unsustainable agricultural practices, which lead to decreasing productivity of grasslands and crops. On the other hand, human influence on improvements involves land abandonment and recovery programs. These results can be used to planning initiatives to better integrate food production with environmental protection in the NNR, contributing to policies to Nigeria achieving land degradation neutrality as soon as possible.

Impact of Human Activities and Climate Change on Grassland Productivity in Xilingol League

Impact of Human Activities and Climate Change on Grassland Productivity in Xilingol League

Plant production and community structure in a mesic semi-natural grassland: Moderate soil textural variation has a much stronger influence than experimentally increased atmospheric nitrogen deposition

Plant production and community structure in a mesic semi-natural grassland: Moderate soil textural variation has a much stronger influence than experimentally increased atmospheric nitrogen deposition

Phenology forecasting models for detection and management of invasive annual grasses

AbstractNon‐native annual grasses can dramatically alter fire frequency and reduce forage quality and biodiversity in the ecosystems they invade. Effective management techniques are needed to reduce these undesirable invasive species and maintain ecosystem services. Well‐timed management strategies, such as grazing, that are applied when invasive grasses are active prior to native plants can control invasive species spread and reduce their impact; however, anticipating the timing of key phenological stages that are susceptible to management over vast landscapes is difficult, as the phenology of these species can vary greatly over time and space. To address this challenge, we created range‐wide phenology forecasts for two problematic invasive annual grasses: cheatgrass (Bromus tectorum), and red brome (Bromus rubens). We tested a suite of 18 mechanistic phenology models using observations from monitoring experiments, volunteer science, herbarium records, timelapse camera imagery, and downscaled gridded climate data to identify the models that best predicted the dates of flowering and senescence of the two invasive grass species. We found that the timing of flowering and senescence of cheatgrass and red brome were best predicted by photothermal time models that had been adjusted for topography using gridded continuous heat‐insolation load index values. Phenology forecasts based on these models can help managers make decisions about when to schedule management actions such as grazing to reduce undesirable invasive grasses and promote forage production, quality, and biodiversity in grasslands; to predict the timing of greatest fire risk after annual grasses dry out; and to select remote sensing imagery to accurately map invasive grasses across topographic and latitudinal gradients. These phenology models also have the potential to be operationalized for within‐season or within‐year decision support.

Integrated modelling of fertilizer and climate change scenario impacts on agricultural production and nitrogen losses in Austria

The European Commission's Farm to Fork strategy aims at reducing nutrient losses and fertilizer use, but has been criticized for its expected negative impacts on European economy, agriculture, and food supply. We apply an integrated modelling framework to analyze potential effects of fertilizer reductions on land use, nitrogen losses, and agricultural output of two fertilizer and four climate change scenarios. The fertilizer scenarios comprise a uniform 20 % reduction of mineral N fertilizer (f20) and a combination of several fertilizer restrictions (fcm). The model results indicate that the restrictions in fertilization lead to decreases in crop production of 6 to 9 %, whereas intensive and extensive grassland production increases. N losses to air, water, and soil are substantially reduced by 9 % (f20) and 20 % (fcm), yet fall short of the intended 50 % reduction. The regional heterogeneity of the model results shows that tailored measures need to be elaborated by taking climate change developments, the regional heterogeneity of prevalent farming systems, and bio-physical conditions into account. Uniform measures applied to the national policy context fall short to attain policy targets cost-effectively. N emission capping, taxes or managerial measures such as crop rotational N balancing are options to be explored in future research.

Cumulative and Lagged Effects: Seasonal Characteristics of Drought Effects on East Asian Grasslands

With the acceleration of global warming, droughts are expected to both intensify and become more frequent. More so than forests, the productivity of grasslands is largely controlled by soil moisture and is highly susceptible to drought. Drought can impact grasslands though the effects may lag and accumulate over time. Because prior research has mainly focused on the annual or growing season scale, it remains unclear whether there are seasonal differences in the cumulative and lagged effects (CALEs) of drought. This study uses Normalized Difference Vegetation Index (NDVI) and Standardized Precipitation Evapotranspiration Index (SPEI) data to explore the seasonal characteristics of the CALEs of drought on grassland growth in East Asia from 2001 to 2020. The main results include the following: (1) More than 40% of grasslands are significantly affected by the CALEs of drought for all three seasons (spring, summer, and autumn). (2) Grasslands are more sensitive to the CALEs of drought in summer. The spatial variability of the cumulative time scale is the greatest in spring, whereas the spatial variability of the lagged time scale is the greatest in summer. The lag time scale gradually shortens as moisture decreases in summer and autumn but shows an inverted U-shape in spring. As drought conditions intensify, the cumulative time scale gradually increases in spring and autumn, while gradually decreasing in summer. (3) The dominant drought effects vary among different seasons: the lagged effect (LE) predominates in spring and autumn, whereas in summer it is the cumulative effect (CE) that dominates. The LE exceeds the CE in 54.89% of the study area during the growing season. We emphasize that annual- or growing season-scale studies of drought CE and LE may obscure seasonal response characteristics. Given the seasonal nature of droughts and the seasonally varying sensitivities of grassland growth to these droughts, the impacts on vegetation fluctuate significantly across different seasons. The results help us more accurately predict grassland ecosystem changes under the background of global warming and the increasing probability of severe drought, providing important reference values for future grassland ecological protection and planning.

The Response of Grassland Production to N and P Fertilizer Management Mediated soil Nematode Community in Qinghai-Tibet Plateau of China

The Response of Grassland Production to N and P Fertilizer Management Mediated soil Nematode Community in Qinghai-Tibet Plateau of China

Mitigating the negative effects of droughts on alpine grassland productivity in the northern Xizang Plateau via degradation-combating actions

The Qinghai-Xizang Plateau, hosting the world’s largest alpine pastures, plays a pivotal environmental role in Asia. These ecosystems face alterations driven by both climate change and anthropogenic activities, resulting in the widespread consideration of grassland degradation. From 2000 to 2020, the northern Xizang Plateau experienced a pronounced escalation in drought conditions, particularly following a management policy aimed at combating grassland degradation, via restricting livestock numbers and implementing fencing enclosures, initiated in 2009. Specially, following the enforcement of this policy (2010–2020), there was a substantial 13.5 % reduction in soil moisture levels compared to the pre-implementation period (2000–2009), accompanied by a 42.8 % increase in drought severity (measured by the Palmer Drought Severity Index, PDSI) and an 11.6 % rise in drought duration. Under these challenging drought conditions, we identified negative trends of potential grassland Net Primary Productivity (NPP) which in absence of anthropogenic influence, as simulated by terrestrial ecosystem model (TEM). Contrary to this simulation, satellite time series observations revealed a widespread increase in actual grassland productivity. Remarkably, despite the challenging drought conditions between 2010 and 2020, we observed a substantial increase of 4.8 % in actual NPP (measured by light use efficiency model), 2.7 % in Normalized Difference Vegetation Index (NDVI), 10 % in solar-induced chlorophyll fluorescence (SIF), and 7.95 % in Gross Primary Productivity (GPP), respectively. Much of this enhancement in grassland productivity occurred in areas where livestock populations had markedly declined. Notably, the percentage of NPP increase mainly caused by degradation-combating actions doubled from 24.8 % during 2000–2009 to 49.8 % during 2010–2020 across the northern Xizang Plateau. In conclusion, our findings highlight the potential of large-scale degradation-combating actions to mitigate the negative impacts of climate change and contribute to a greener Earth.

Discovering the role of fairy ring fungi in accelerating nitrogen cycling to promote plant productivity in grasslands

Soil microorganisms play a key role in the provision of plant-bioavailable nutrients, which is crucial for ecosystem functioning and plant productivity. Fairy rings are widespread features in grasslands accompanied by lush dark-green vegetation bands. This enigmatic feature is caused by increased soil bioavailable nitrogen (N) due to the expansion of fairy ring fungi (FRF). However, little is known about how FRF enhance soil bioavailable N concentrations. Here, we conducted a survey of 35 fairy rings in temperate grasslands to reveal the role of FRF in regulating soil microorganisms and N cycling using amplicon and metagenomic sequencing. The presence of FRF accelerated organic N mineralization via promoting extracellular enzyme (β-1,4-N-acetylglucosaminidase) activity, leading to a 455% increase in ammonium-N. This further stimulated nitrification to enhance nitrate-N concentration by favoring ammonia-oxidizing archaea. Concomitantly, the increased nitrate-N did not promote denitrification or affect the potential risk of N loss. Furthermore, the relative abundance of other saprotrophic and symbiotrophic fungi was significantly reduced by FRF but the changes in these fungi did not affect the activity of extracellular enzymes involved in N mineralization. Our results suggest that FRF can act as ecosystem engineer species shaping fairy rings by driving soil N cycling without the involvement of other microbial functional groups of saprotroph and symbiotroph to boost plant productivity. Thus, due to the stronger N mobilizing ability, FRF show great potential to be exploited as beneficial microorganisms in plant production and sustainable agricultural development.

Assessing Ecological Compensation Policy Effectiveness: A Case Study in the Inner Mongolia Autonomous Region, China

As a vital component of the terrestrial ecosystem, grassland accounts for one-third of the global vegetation system. Grassland degradation has been exacerbated due to extreme overgrazing in China’s Inner Mongolia Autonomous Region (IMAR). While conservation was carried out via the Ecological Subsidy and Award Program (ESAP) to mitigate grassland degradation, little is known about its effectiveness in improving the biophysical conditions of grassland. This paper integrates the conceptual frameworks of total socio-environmental systems (TSESs) to assess how ecological systems respond to the ESAP, investigate the spatial heterogeneity of the ESAP, and explore the meddling effects of socio-environmental interactions on the ESAP. We integrated ecological, climate, and socioeconomic data and developed several hierarchical linear mixed models (HLMMs) to investigate how these factors interact with the ESAP in the IMAR. Our findings prove that the above-ground biomass between 2011 and 2015 responds significantly to variations in socioeconomic conditions and ecological communities. Available land resources, hospital and medical facilities, and net farmer and herdsman income are the most critical factors positively related to grassland productivity. Primary industries like mining, total consumer retail value, farming, forestry, animal husbandry, fishery productions, and GDP are the most damaging factors affecting biomass. Our study recommends a regionally or locally tailored ecological recovery policy, instead of a generalized one, in future efforts to conserve grassland.

From crisis to opportunity: climate change benefits livestock production in Somalia

Abstract While livelihoods of Somalian livestock smallholders rely heavily on seasonal climate conditions, little is known of long-term implications of the changing climate for this nation. Here, we quantify implications of the changing climate on the productivity and profitability of livestock smallholders across a rainfall gradient in northwestern Somalia. Using the Sustainable Grazing Systems (SGS) model, we explore 80 future climate realisations, with global climate model projections including low- and high-impact socio-economic pathways (SSP245 and SSP585), two climate horizons (2040 and 2080) and four case study farm regions. In general, future seasonal and annual rainfall and temperature relative to the baseline period (1981–2020) increased for most regions. Mean annual temperatures increased by 9%–14%, while cumulative annual precipitation increased by 37%–57% from mid to late century, respectively. Grassland production increased with later climate horizons, as higher average annual rainfall together with elevated atmospheric carbon dioxide drove up growth rates in spring and autumn. Under the low emissions scenario (SSP245), changes in farm profit were modest or positive, ranging from negative 4% in Berbera–20% plus in Sheikh. Under the higher emissions scenario (SSP585), farm profits were higher, ranging from 23% to 42% above baseline profits, largely due to greater pasture production and lower requirements for supplementary feed. We conclude that future climates will benefit the productivity and profitability of smallholder farmers in Somalia, although more agile farm management will be required to cope with increased seasonal climate variability.

Paralleled grazing and mowing differentially affected plant community diversity and productivity in a semi-arid grassland

BackgroundNumerous previous studies have investigated the effects of grazing or mowing on plant community diversity and productivity in grasslands; however, few have deliberately made sound comparison between the effects of paralleled grazing and mowing in terms of biomass removal on plant community diversity and productivity in semi-arid grasslands. Using a 4-year field manipulative experiment, we investigated how moderate intensity of domestic cattle (Bos taurus) grazing and mowing can affect plant community diversity and productivity in the semi-arid grassland in northeastern China, with the attempt to find a better management practice.ResultsOur results showed that grazing significantly increased plant species richness by 9% but did not change plant biomass, whereas mowing did not alter plant species richness but significantly reduced total plant biomass and root biomass by 18% and 12%, respectively, and significantly altered plant community composition, reflected by 32% increase of grass to forb biomass ratio.ConclusionsCattle grazing exerted a neutral effect on plant biomass and a positive effect on plant species richness, suggesting that cattle grazing is a better management practice compared to the paralleled mowing, but longer-term experiments are needed to explore the lasting influences of grazing vs. mowing on grassland productivity, plant diversity and the sustainability.

Impact of water stress on Mediterranean oak savanna grasslands productivity: Implications for on-farm grazing management

This study analyzes the productivity of grasslands in a Mediterranean oak-savanna ecosystem, focusing on its linkages with water availability. In these water-controlled ecosystems, grassland environmental preservation and sustainable management depend on quantitatively understanding these links. Productivity and water stress were modeled in southern Spain (2001–2018), integrating meteorological information and MODIS sensor data into a light-use efficiency model and a surface energy balance. The results provided valuable insights into how grasslands behaved during droughts at different spatiotemporal scales. During the most significant droughts, 2004/2005 and 2011/2012, aerial biomass production was reduced by 42 % and 67 %, respectively. The spatial analysis identified the central east side of the region, with low slopes and moderate tree cover, as the most productive area. The biomass production time series classification identified four distinct trends, all showing shifted relationships with similar slopes between production and anomalies of relative evapotranspiration. The seasonal analysis highlighted the importance of autumn, accounting for nearly 30 % of the annual biomass production, which was essential in years with spring water deficits. The proposed methodology provides on-farm grassland production curves depending on water availability (max-mean-min range with a mean error of 15.5 %). Together with weather forecast data, this could help farmers decide on the optimal level of management intensification and stocking rate. Although the regional specificity may limit the study’s direct applicability, this scheme offers valuable metrics that could be adapted to other areas under water scarcity conditions.

Soil health is associated with higher primary productivity across Europe.

Soil health is expected to be of key importance for plant growth and ecosystem functioning. However, whether soil health is linked to primary productivity across environmental gradients and land-use types remains poorly understood. To address this gap, we conducted a pan-European field study including 588 sites from 27 countries to investigate the link between soil health and primary productivity across three major land-use types: woodlands, grasslands and croplands. We found that mean soil health (a composite index based on soil properties, biodiversity and plant disease control) in woodlands was 31.4% higher than in grasslands and 76.1% higher than in croplands. Soil health was positively linked to cropland and grassland productivity at the continental scale, whereas climate best explained woodland productivity. Among microbial diversity indicators, we observed a positive association between the richness of Acidobacteria, Firmicutes and Proteobacteria and primary productivity. Among microbial functional groups, we found that primary productivity in croplands and grasslands was positively related to nitrogen-fixing bacteria and mycorrhizal fungi and negatively related to plant pathogens. Together, our results point to the importance of soil biodiversity and soil health for maintaining primary productivity across contrasting land-use types.

Ecosystem multifunctionality is more related to the indirect effects than to the direct effects of human management in China's drylands

Drylands provide a wide range of important ecosystem functions but are sensitive to environmental changes, especially human management. Two major land use types of drylands are grasslands and croplands, which are influenced by intensive grazing activities and agricultural management, respectively. However, little is known about whether the ecosystem functioning of these two land use types is predominated affected by human management, or environmental factors (intrinsic environmental factors and factors modified by human management). This limits our understanding of the ecosystem functions under intensive human management in drylands. Here we reported a study where we collected data from 40 grassland and 30 cropland sites along an extensive aridity gradient in China's drylands to quantify the effects of human management intensity, intrinsic environmental factors (i.e., aridity), and environmental factors modified by human management (i.e., soil bulk density and plant density) on specific ecosystem functions (ecosystem multifunctionality, productivity, carbon storage, soil water, and soil nutrients). We found that the relative importance of each function differed between croplands and grasslands. Ecosystem functions varied with human management intensity, with lower productivity and plant carbon storage in grasslands under high grazing intensity than un-grazed, while multifunctionality and carbon storage increased with greater fertilization only in arid croplands. Furthermore, among environmental factors, soil bulk density had the greatest negative effects, which directly reduced multifunctionality in grasslands and indirectly reduced multifunctionality in croplands via suppressing crop density. Crop density was the major environmental factor that positively related to multifunctionality in croplands. However, these effects would be exacerbated with increasing aridity. Our study demonstrated that compared with the direct impacts of human management, environmental factors modified by human management (e.g., soil bulk density) are the major drivers of ecosystem functions, indicating that improving soil structure by alleviating human interferences (e.g., reducing livestock trampling) would be an effective way to restore ecosystem functions in drylands under global warming and drying.

Resistance of grassland productivity to drought and heatwave over a temperate semi-arid climate zone

Drought and heatwave are the primary climate extremes for vegetation productivity loss in the global temperate semi-arid grassland, challenging the ecosystem productivity stability in these areas. Previous studies have indicated a significant decline in the resistance of global grassland productivity to drought, but we still lack a systematic understanding of the mechanisms determining the spatiotemporal variations in grassland resistance to drought and heatwave. In this study, we focused on temperate semi-arid grasslands of China (TSGC) to assess the spatiotemporal variations of grassland productivity resistance to different climate extremes: compound dry-hot events, individual drought events, and individual heatwave events that occurred during 2000–2019. Based on the explainable machine learning model, we explored the resistance to the interaction of drought and heatwave and identify the dominant factors determining the spatiotemporal variations in resistance. The results revealed that grassland resistance to climate extremes had decreased in Xilingol Grassland and Mu Us Sandy Land, and had a not significant increase in Otindag Desert during 2000–2019. Human activities and the increase in CO2 concentration causes a decline in resistance in Mu Us Sandy Land, and the increase of VPD and shift of vegetation loss event timing caused a decline in resistance in Xilingol Grassland, while the weakening of climate extremes, especially the shortening of drought duration, increase the resistance in Otindag Desert. Mean annual temperature dominates the spatial differences in resistance among different grasslands. When drought and heatwave occur simultaneously, there is an additive effect on resistance and causes lower resistance to compound dry-hot events compared to individual drought and heatwave events. Our analysis provides crucial insights into understanding the impact of climate extremes on the temperate semi-arid grasslands of China.

Extraction of grassland irrigation information in arid regions based on multi-source remote sensing data

Irrigation is a vital measure for maintaining grassland productivity in arid and semi-arid regions. Grasslands typically have characteristics such as unclear boundaries, complex vegetation types, and relatively small irrigation amounts, making it challenging to extract irrigation information. Currently, research on extracting grassland irrigation information is scarce. This study proposes a method for extracting grassland irrigation information using high spatiotemporal resolution (30 m, 1 day) downscaled surface soil moisture data, combined with Landsat 8/9 and Sentinel 1/2 data. This method was applied to extract the irrigation area, timing, and frequency of grasslands in the Delingha Piedmont, northwestern China. The results showed that the overall classification accuracy of irrigated grassland was 93.43 %, and the kappa coefficient was 0.91, indicating high extraction accuracy. The average values of recall, precision, and F-score for irrigation timing and frequency were 82.54 %, 72.25 %, and 77.03 %, respectively, with most irrigation events accurately identified, indicating commendable overall efficacy. The combined use of multi-source remote sensing data is crucial for the extraction of grassland irrigation information. Among these, The high spatiotemporal resolution downscaled surface soil moisture data, by providing detailed spatiotemporal surface soil moisture dynamics, demonstrate a potent capacity for capturing irrigation events, thus effectively enhancing the accuracy of grassland irrigation data extraction.

Effects of soil characteristics on grassland productivity in long-term artificial grassland establishment

The long-term establishment of artificial grasslands is considered one of the most rational management models for restoring the "Black Soil Beach, BSB" which promotes ecological succession characterized by increased biodiversity and improved soil health in the BSB. However, the relationship between grassland productivity recovery and soil stoichiometric balance during the long-term establishment process remains unclear. To elucidate this relationship, this study explored the impact mechanisms of soil nutrients, carbon and nitrogen sequestration, and soil stoichiometric features on grassland biomass across eight establishment periods (BSB, 1 year, 2 years, 5 years, 6 years, 10 years, 11 years, and 20 years). The results indicated that compared to the baseline BSB conditions, the aboveground biomass in artificial grasslands showed an increase ranging from 237.48 % to 815.1 %. The soil organic carbon stocks (SOCS) for 1-year-old artificial grassland (AG1), 2-year-old artificial grassland (AG2), 5-year-old artificial grassland (AG5), 6-year-old artificial grassland (AG6), 10-year-old artificial grassland (AG10), 11-year-old artificial grassland (AG11), and 20-year-old artificial grassland (AG20) increased by 79.7 %, 62.8 %, 60.6 %, 59.9 %, 87.5 %, 38.5 %, and 59.3 %, respectively, and the soil nitrogen stocks significantly increased during the early and middle stages of establishment. Moreover, as the establishment period prolonged, the 0–30 cm soil stoichiometric ratios (C:N, C:P, C:K, N:K, and P:K) significantly improved. Structural equation modeling revealed that soil stoichiometric ratios did not directly affect biomass, while the establishment period influenced plant uptake of total and available soil nutrients by altering soil physical properties, ultimately affecting biomass. This study unveils the mechanisms by which soil carbon and nitrogen sequestration, soil nutrients, soil stoichiometric ratios, and plant characteristics affect the productivity of long-term established artificial grasslands. These findings contribute to the development of management strategies for the sustainable restoration and conservation of alpine meadow ecosystems.

Disembedding and Disentangling Grassland Valuation: Insights into Grassland Management Institutions and Ecological Research in China

After two decades of implementing top-down grassland restoration projects focused on reducing livestock numbers and pastoralist populations, the Chinese government’s well-funded efforts have not significantly reversed grassland degradation. This study reviews the institutional changes in grassland management over the past forty years, highlighting the Livestock and Grassland Double Contract Household Responsibility System of the early 1980s and the Grassland Ecological Reward and Compensation Policy introduced in 2011. It demonstrates how these institutional transformations have shaped pastoralists’ evolving understanding of grassland value and reveals that commodifying grassland’s economic and ecological value has led to the capitalization of nature, disembedding husbandry from grassland production, and undermining the effectiveness of conservation projects. This article also showcases the development of grassland ecology research in China, noting its increasing detachment from a holistic understanding of ecosystems and the interdisciplinary needs of management practices. The disjunction between grassland ecology research and practical management has resulted in a lack of techniques aligned with local ecological and socioeconomic contexts. This article champions active engagement with and protection of pastoralist communities to reintegrate grasslands’ true economic and ecological value into management practices, thereby effectively restoring degraded grasslands and achieving sustainable management.

Characterizing microenvironmental factors and the forest component in the production of natural grasslands in a silvopastoral system with Eucalyptus grandis

Characterizing microenvironmental factors and the forest component in the production of natural grasslands in a silvopastoral system with Eucalyptus grandis