Rangeland Ecology & Management最新文献

Rangelands cover half of the world's land surface, yet they are often threatened by multiple factors, such as the encroachment of woody plant populations. This comprehensive review investigates the fusion of ecohydrology, remote sensing, and modeling approaches to tackle this global issue. We discuss the consequences of woody plant encroachment (WPE) and consider effective strategies for preventing or mitigating encroachment in rangeland ecosystems. We highlight the importance of understanding the complex interactions between biotic and abiotic factors that accelerate these processes and the need for interdisciplinary approaches to address this issue. We also identify a range of challenges intrinsic to WPE management, including the need for deeper insights into the catalysts of WPE and their impacts on ecohydrological connectivity across diverse ecosystems. This review also emphasizes the role of remote sensing in monitoring WPE and the potential of modeling approaches to inform management decisions. We highlight the significance of comprehending regional nuances, and the influences of climate change, and encourage the development of strategies to improve collaboration among stakeholders engaged in management initiatives. We also reiterate the necessity of integrating the human dimension, including policy formulation and landowner perspectives, into effective WPE management and restoration projects. We advocate for a holistic, integrated approach to shaping the future of rangeland management in an ever-evolving global landscape.

Spring and summer rainfall patterns in Mongolian semi-arid grazing lands vary greatly from year to year, and are thought to affect the energy balance and nutritional conditions of sheep via plant community changes. To test this, climatic and vegetation data in Mongolian semiarid grasslands were obtained from spring to summer over 3 yr. For 2 yr, sheep energy intake and expenditure were calculated, and the energy balance and nutrition indicators were compared among years with different seasonal rainfall patterns. In 2019 and 2022, rainfall patterns were characterized by the presence and absence of early summer drought, respectively. Compared to 2019, plants were tall and abundant in 2022; thus, the mean bite size, energy intake, and body weight were higher. Estimated energy intake and expenditure were 4.56 and 2.10 Mcal in 2019, and 6.75 and 1.63 Mcal in 2022, respectively, indicating that rainfall timing and amount affected vegetation assemblage, plant height, herbage nutrition, grazing behavior, animal energy balance, and nutrition conditions. Insufficient rainfall before early summer in semiarid grazing lands resulted in low energy intake and balance, and delayed body weight gain could not be recovered. These results can inform the management of grazing lands to ensure optimal livestock conditions.

Management of grasslands for agriculture and other land uses is a critical issue for the conservation of grassland animals, both due to direct effects on mortality, as well as indirect effects such as altered predation regimes. In this study, we investigated the effect of mowing on the predation pressure by birds on an endangered snake, the Hungarian meadow viper (Vipera ursinii rakosiensis), using plasticine snake models. We placed 200 snake models each in mowed hayfields and grazed pastures (as controls) in two study periods, before and after mowing on hayfields, in 2021 and 2022. We found no strong negative effects of mowing on attack rates by birds in our study. Attack rates on snake models were higher before mowing than after mowing, and in general lower in the second year of the study than in 2021. However, in 2021 attack rates on snake models in pastures were higher than on hayfields, but this pattern reversed in 2022, when attacks were more frequent on hayfields than pastures. Our study highlights the importance of considering potential factors influencing predation pressure and predator-prey dynamics in grassland habitats, as well as the need for further research to provide results for evidence-based conservation management strategies to mitigate population declines and local extinction risk.

Rangeland ecosystems, and their managers, face the growing urgency of climate change impacts. Researchers are therefore seeking integrative social-ecological frameworks that can enhance adaptation by managers to these climate change dynamics through tighter linkages among multiple scientific disciplines and manager contexts. Social-ecological framings, including resilience and vulnerability, are popular in such efforts, but their potential to inform meaningful rangeland adaptation science is limited by traditional disciplinary silos. Here, we provide reflective lessons learned from a multidisciplinary Rangelands, Ranching, and Resilience (R3) project on U.S. western rangelands that addressed 1) biophysical science projections of forage production under future climate scenarios, 2) ranchers’ views of resilience using social science methods, and 3) outreach efforts coordinated through extension professionals. Despite the project's initial intentions, human dimensions and ecological researchers largely worked in parallel sub-teams during the project, rather than weaving their expertise together with managers. The R3 project was multidisciplinary, but it provides a case study on lessons learned to suggest how social and ecological researchers can move towards approaches that transcend individual disciplines. Transdisciplinary science and management in rangelands requires more than just conceptual social-ecological frameworks. Additional methodological concepts need to include: 1) relationship building; 2) shared meaning making; and 3) a commitment to continual conversations and learning, or staying with the trouble, following Haraway (2016). If the goal is to address meaningful rangeland adaptation science rather than just produce academic products, researchers, outreach professionals, and rangeland-based communities should address a series of critical troubling questions. In the process of addressing these, deeper engagement among and beyond disciplines will occur as relationship building, shared meaning, and continual conversations and learning facilitate staying with the trouble.

In savanna ecosystems, fire is common, yet little is known on the direct and long-term effects of prescribed burns on arthropod abundance, richness, diversity, and composition. To understand the impact of fire on arthropods at Kruger National Park (KNP), standardized pitfall traps and active searches were used to collect arthropods at unburnt, annually burnt, and triennially burnt plots of the long-term experimental burnt plots (EBPs). Abundance, richness, diversity, and assemblage composition of arthropods were compared across EBPs. Results showed that arthropods from the order Hymenoptera, particularly those in the family Formicidae, were the most abundant (76.4%), followed by Coleoptera (18.6%), Araneae (3%), Orthoptera (1%), and other small/less dominant orders (1%). However, the species richness of arthropods from Coleoptera was high (30.2%) compared with Formicidae (24.6%), Araneae (24.6%), and Orthoptera (4%). Abundance, richness, diversity, and assemblage composition of multitaxon and Formicidae were significantly different among EBPs. Although the abundance of multitaxon and Formicidae was significantly high at unburnt plot, species richness and diversity were low while the assemblage composition was unique at this plot compared with the annually and triennially burnt. Furthermore, the assemblage of arthropods in annually burnt EBP differed compared with those collected at unburnt and triennially burnt EBPs. We conclude that the frequency of prescribed fires improves the richness, diversity, and assemblage composition of arthropods with a significant reduction of abundances. Thus, fire can be used as a conservation tool for arthropods in the protected savanna of KNP.

Land use and land cover change (LULC) play a critical role in influencing ecosystem processes, biodiversity, hydrology, and climate. In recent years, human activities have greatly influenced changes in LULC more than ever before. The Yayo Coffee Forest Biosphere Reserve (YCFBR) is currently experiencing major effects from human activities, such as the spread of forest fires and the expansion of coffee plantations. The objective of this study is to quantify changes in LULC and their effects on ecological preservation within the YCFBR from 1992 to 2022. Landsat images from 1992, 2002, 2012, and 2022 were used for the study after the application of common image preprocessing techniques such as geometric and radiometric correction algorithms. A supervised image classification method using maximum likelihood algorithms was used to create LC maps consisting of six different LULC types in ERDAS Imagine software. The results revealed that throughout the study period, there was a consistent 80.81% of open forests that remained unchanged, while 79.08% of high forests stayed high forests. Similarly, the percentage of agricultural land that remained unchanged was 72.77%, while the percentage of built-up areas that remained the same was 62.84%. Grazing land experienced a conversion of about 58%, followed by high forest with (13.65%) conversion into open forest, whereas 22% of the agricultural land was converted to built-up area. About 62% of the YCFBR landscape persisted during the study period, while the total net change accounted for 59% of the total change in the area. The study's results can be used as valuable input for planning biodiversity management in the region, helping policymakers improve management strategies for LU, and potentially reducing pressure on high forest areas.

Domestic livestock grazing is the primary land use across the planet, but the relationship between grazing and rangeland productivity is difficult to determine because it is influenced by a variety of ecological and management factors. Fine-scale environmental data available through remote sensing are increasingly used to understand land use changes, such as grazing. In this study, we assessed the relationship between a variety of grazing and rangeland productivity metrics while accounting for environmental complexity within the sagebrush steppe ecosystem of Montana. We created mixed-effect generalized linear models using remotely sensed productivity as response variables. Explanatory variables included management and field-based grazing data combined with remotely sensed abiotic and biotic environmental factors. We found point-level field measures of grazing (e.g., cow patties, percentage of dung in Daubenmire plots, and number of plants grazed) showed positive effects, especially on perennial forbs and grasses. Grazing measures at the pasture-level showed a small negative effect on annual forbs and grasses. Grazing metrics tended to have smaller covariate effects on rangeland productivity compared to environmental factors, and interaction effects between grazing and environmental factors were common. This study provides insight into the relationship between grazing and plant productivity in the sagebrush steppe rangeland of Montana and highlights the importance of assessing the effects of grazing using multiple scales while accounting for environmental complexity.

High-density short-duration grazing (SDG) is widely suggested to increase productivity. Among various SDG practices, the most widespread and popular, “holistic grazing,” claims to mimic the movement patterns of wild African ungulate herds to improve rangeland health and promote biodiversity. However, this claim has rarely been empirically tested. Focusing on Karoo Escarpment Grasslands in the eastern Karoo, South Africa, we compared patch use patterns of black wildebeest (Connochaetes gnou) in a continuously grazed wildlife system with cattle paddock use on farms implementing SDG management in the same landscape. Camera trap data revealed heterogeneous wildebeest patch use over the 26-mo sampling period, with wildebeest consistently using some patches more intensely than others. Mean intensity of patch use by wildebeest varied with a factor of 10, from 0.05 LSU · ha⁻¹ · day⁻¹ to 0.51 LSU · ha⁻¹ · day⁻¹ across patches. The relative difference in mean intensity of paddock use among farms ranged across a similar magnitude from < 0.01 to 0.18 LSU · ha⁻¹ · day⁻¹ for least to most intensely grazed paddocks, respectively. Grazing durations in wildebeest patches ranged from 3-15 d (mean = 8 d), compared to the range of 3-60 d (mean = 18 d) for cattle. Intense grazing periods in wildebeest patches ranged from 0 to 2 d (mean = 1 d) and from 1 to 30 d (mean = 7 d) across cattle farms. The greatest difference was between rest intervals, lasting from 1 to 5 d on average across wildebeest patches, compared to 60–365 d across cattle farms. Our findings suggest that SDG systems prevalent in Karoo Escarpment Grasslands differ from the patch use patterns of black wildebeest in most aspects. These findings add to growing literature on grazing behavior of wild herbivores, and effectively contrasts these patterns with SDG cattle farming practices in the same landscape.

Although several strategies can be used for pasture recovery, pasture degradation remains an issue in Brazilian cattle raising. The use of shrub legumes can change the environment (microclimate and water consumption) and productive potential of the pasture. Therefore, the objective of this study was to evaluate the effect of two pasture recovery strategies on the microclimate, soil water dynamics, and forage accumulation of tropical pastures. The research was conducted between 2020 and 2022 in signalgrass (Urochloa [syn. Brachiaria] decumbens Stapf cv. Basilisk) pastures managed under continuous and variable stocking rate throughout the experimental period in São Carlos, SP, Brazil. Three production systems were assessed: 1) degraded pasture without N fertilization (DEG); 2) recovered pasture with application of 200 kg N-urea ha⁻¹ yr⁻¹ (REC); and 3) recovered pasture by intercropping with pigeon pea (Cajanus cajan L. Millsp. cv. BRS Mandarim) (MIX). Soil moisture in the 0–60 cm layer and microclimate, which included photosynthetically active radiation and the animal thermal comfort index, were assessed. The vegetative and productive characteristics of pastures, as well as the total mass production of the production systems, were also evaluated. Overall, intercropping pigeon pea plants with tropical pasture did not significantly affect the soil water content or the animal thermal comfort index. However, it did alter the transmission of photosynthetically active solar radiation to the pasture (0%‒65%) and decreased wind speed (0%‒60%). During the 2 yr, the pigeon pea exhibited a great forage accumulation potential (12 615 kg·ha⁻¹·yr⁻¹). Additionally, pigeon pea provided high-quality forage available during the dry season. Forage accumulation increased in both pasture recovery strategies (REC and MIX), with a significantly greater amount of crude protein (CP) content in the MIX. Intercropping tropical pastures with pigeon pea can be used as a strategy for pasture recovery and dry season forage supplementation.