Semi-arid Rangelands Research Articles

Social interactions and movement patterns of rangeland-raised beef cows and their calves

Understanding the spatial and temporal relationships between beef calves and their dams is crucial for effective rangeland management. This study investigated these dynamics on semiarid rangeland using GPS collars fitted on cow-calf pairs. Data were collected on 46 crossbred cows and 34 calves grazing two adjacent 219 and 146 ha pastures. The primary objective was to determine the proximity of calves to their dams and other adult cows at different calf ages (1, 2 and 4 mos.). Over a 24 h period, calves spent on average 10.5 and 17.5 h within 5 or 10 m of an adult cow, respectively, and spent 2.6, 5.6 and 2.3 h within 5 m of their dams, other adult cows and a guard cow (cow other than the dam that spent the most time in the proximity of a calf), respectively. Calves spent more time within 5 or 10 m of an adult cow during night vs. daytime hours and spent detectably (P < 0.05) more time within 5 or 10 m of other adult cows vs. their dam (5.6 vs. 2.6 or 10.3 vs. 3.5 h). Calves spent a similar (P > 0.05) amount of time within 5 or 10 m of their dam vs. the guard cow (2.6 vs. 2.3 or 3.5 vs. 3.7 h) regardless of age during both day and nighttime hours. In general, calves spent more time within 5 and 10 m of an adult cow at 2 vs. 1 or 4 mos. of age. Greater mother-offspring clustering occurred at 2 vs. 1 or 4 mos. of age regardless of the spatial threshold considered. Regardless of calf age, calves and nursing cows traveled on average 4.5 and 6.7 km/day, respectively. Calves at 4 mo of age traveled farther than younger calves. Nursing cows traveled farther when calves were 4 mo. vs. 1 or 2 mos. of age and tended to travel farther when calves were 1 vs. 2 mos. old. Calves spent more time close to other nursing cows vs. their dam. These findings suggest that while dams play a crucial role in calf development, other nursing cows may also influence their foraging behaviors. Further research is needed to fully understand the dynamics of these relationships and their implications for rangeland management, such as optimizing grazing strategies and improving calf health and productivity.

GPS-Based Hidden Markov Models to Document Pastoral Mobility in the Sahel.

In agrarian systems where animal mobility is crucial for feed management, nutrient cycles and household economy, there is a notable lack of precise data on livestock mobility and herding practices. We introduce a methodology leveraging GPS-based behavioural models to analyse and document pastoral mobility in the Sahel. Over 2.5 years, we conducted a continuous collection of GPS data from transhumant and resident cattle herds in the Senegalese agropastoral semiarid rangelands. We developed a Hidden Markov Model robustly fitted to these data to classify recordings into three states of activity: resting (47% overall), foraging (37%) and travelling (16%). We detail our process for selecting the states and testing data subsets to guide future similar endeavours. The model describes state changes and how temperature affects them. By combining the resulting dataset with satellite-based land-use data, we show the distribution of activities across landscapes and seasons and within a day. We accurately reproduced key aspects of cattle mobility and characterised rarely documented features of Sahel agropastoral practices, such as transhumance phases, nocturnal grazing and in-field rainy season paddocking. These results suggest that our methodology, which we make available, could be valuable in addressing issues related to the future of Sahelian pastoralism.

DEMYSTIFYING AGRICULTURAL POPULISM IN MAASAI RANGELANDS IN THE SOUTHWESTERN KENYA

Agricultural expansion in Kenya’s Amboseli region has resulted in proven negative effects both on native megafauna that use the ecosystem as a dispersal area, as well as on grazing and water resources utilized by local livestock herds. While community conservancy programs supported by non-governmental organizations (NGOs) provide an ecologically sustainable alternative to farming’s increasing popularity, the claim that agriculture is the most profitable land-use option for the region remains dominant –– even as increasingly frequent droughts interrupt agricultural processes. This study presents a comparative analysis of the overall benefit of land-use– agriculture and conservancies– in the Amboseli region. We draw on fieldwork conducted between March - May 2023, in the former Kimana Group Ranch in the Amboseli region of southwestern Kenya. Data was collected through household surveys with 150 landowners, and key informant interviews with leaders and officers of various conservancies and NGOs in the area. We conducted approximate analyses of the annual cash flow reported by each household to compare the profitability of different land-use options. The results of the study show that, while agriculture is by far the most popular land-use option in Amboseli, the region’s traditional pastoralist practices remain the most financially stable and lucrative land-use option. Leasing land for conservation through community conservancies was the second most profitable. Irrigated agriculture, mostly practiced by non-Maasai people, showed relatively short-lived financial returns. We argue that increased farming in Maasai rangelands is fueled primarily by land privatization and the promise of immediate profits –– promises whose benefits are far outweighed by long-term economic and socio-ecological consequences. Considering that indigenous Maasai pastoralism is most sustainable for the semiarid rangeland and that our research indicated agriculture is practiced most by non-Maasai, we argue for an examination of how traditional ecological knowledge (TEK) competes with non-indigenous practices, especially considering that rangelands in East Africa are increasingly becoming fragile due to climate change.&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt; Article visualizations:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;img src="/-counters-/soc/0821/a.php" alt="Hit counter" /&gt;&lt;/p&gt;

Multiple plant-community traits improve predictions of later-stage outcomes of restoration drill seedings: Implications for metrics of success

Success of ecological restoration is often only knowable if treatments meet criteria defined by biotic thresholds, but analytical frameworks to determine metrics of success and their underlying thresholds are needed. Early indicators of longer-term recovery trajectories are particularly critical where re-treatments may be required, such as in harsh climates or where repeated disturbances or invasive pressures prevail. We developed a framework for identifying which biotic traits would provide the best initial indication of longer-term target restoration goals and applied the framework to restoration drill-seedings of deep-rooted perennial bunchgrasses (DRPBGs) used to rehabilitate and restore semiarid rangelands threatened by exotic annual grasses (EAGs, e.g. cheatgrass) and the recurrent wildfire that EAGs cause. Initial traits measured included cover, basal diameter, height, and density (#plants/area) of DRPBGs and cover of EAGs and Sandberg bluegrass (Poa secunda, POSE, a disturbance-adapted perennial). The longer-term target objective was ≥25 % DRPBG cover and ≤13 % EAG cover by the 5th year following drill-seedings. Measurements were made on 112 plots spanning 113,000 ha in sagebrush steppe on the Soda wildfire scar, in the Northern Great Basin, USA. Traits of DRPBGs tended to be uncorrelated with one another, thus each was informative in describing vegetation condition. Where DRPBG cover was initially >17 %, it tended to become >25 % by the 5th-year post-seeding. In plots that overcame an initial risk of not meeting the target objective (i.e. <17 % initial DRPBG cover), DRPBG tended be large DRPBGs (>22.8 cm height) and plots also had >7 % cover of POSE. Additional “sets” of initial vegetation traits were also predictive of longer-term restoration success or failure. Restoration drill-seeding of DRPBGs is a key but varied-outcome tool for breaking the exotic grass-fire cycle, and, contrary to a conventional tendency to rely on a limited number of mean traits such as % cover, a suite of biotic traits appears necessary to monitor to reliably know if trials are likely to yield success.

Relative abundance of a mesocarnivore in a human-dominated, semi-arid rangeland in Namibia

Mesocarnivores fill important roles in ecological communities globally, but their distribution and abundance are often understudied. Many species have historically been regarded as vermin and subject to lethal control due to their role in livestock predation. Identifying the factors influencing mesocarnivore populations can help disentangle their relationship within ecological communities and inform conflict mitigation and conservation priorities. To help identify these factors, we used camera traps to study the community of medium and large mammals in four communal conservancies of northeastern Namibia covering the wet and dry seasons using 99 and 97 camera trap stations, respectively. We modelled black-backed jackal (Lupulella mesomelas) abundance using the robust Royle-Nichols model. Black-backed jackal were widespread, with a mean per site abundance of 2.01 (SD=0.66) in the wet season and 2.41 (SD=0.49) in the dry season. Black-backed jackal showed seasonally contrasting covariate associations, with lower abundance in areas with medium and large-sized wild prey during the wet season, and higher abundance in areas with more villages and close to African wild dog (Lycaon pictus) dens in the dry season. We identified localized hotspots of black-backed jackal abundance during the dry season, which may indicate that when resources are scarce, black-backed jackals rely on anthropogenic food sources despite an elevated risk for conflict, and on carcass remains from African wild dog kills. These findings highlight potential drivers of mesocarnivore abundance that would be obscured in a conventional occurrence modelling framework, and illustrate how local abundance may be influenced by seasonal variability, wild and anthropogenic food sources, and a likely facilitative relationship with a large carnivore. Further investigations in areas with more complex carnivore guilds and higher density of dominant predators are needed to understand black-backed jackal-African wild dog interactions and impacts on population dynamics.

Relationship between Vegetation and Soil Moisture Anomalies Based on Remote Sensing Data: A Semiarid Rangeland Case

Relationship between Vegetation and Soil Moisture Anomalies Based on Remote Sensing Data: A Semiarid Rangeland Case

Fine spatial scale assessment of structure and configuration of vegetation cover for northern bobwhites in grazed pastures

BackgroundMonitoring forage in livestock operations is critical to sustainable rangeland management of soil and ecological processes that provide both livestock and wildlife habitat. Traditional ground-based sampling methods have been widely used and provide valuable information; however, they are time-consuming, labor-intensive, and limited in their ability to capture larger extents of the spatial and temporal dynamics of rangeland ecosystems. Drones provide a solution to collect data to larger extents than field-based methods and with higher-resolution than traditional remote sensing platforms. Our objectives were to (1) assess the accuracy of vegetation cover height in grasses using drones, (2) quantify the spatial distribution of vegetation cover height in grazed and non-grazed pastures during the dormant (fall–winter) and growing seasons (spring–summer), and (3) evaluate the spatial distribution of vegetation cover height as a proxy for northern bobwhite (Colinus virginianus) habitat in South Texas. We achieved this by very fine scale drone-derived imagery and using class level landscape metrics to assess vegetation cover height configuration.ResultsEstimated heights from drone imagery had a significant relationship with the field height measurements in September (r2 = 0.83; growing season) and February (r2 = 0.77; dormant season). Growing season pasture maintained residual landscape habitat configuration adequate for bobwhites throughout the fall and winter of 2022–2023 following grazing. Dormant season pasture had an increase in bare ground cover, and a shift from many large patches of tall herbaceous cover (40–120 cm) to few large patches of low herbaceous cover (5–30 cm) (p < 0.05).ConclusionsDrones provided high-resolution imagery that allowed us to assess the spatial and temporal changes of vertical herbaceous vegetation structure in a semi-arid rangeland subject to grazing. This study shows how drone imagery can be beneficial for wildlife conservation and management by providing insights into changes in fine-scale vegetation spatial and temporal heterogeneity from livestock grazing.

Dynamics in bush cover, local uses of encroaching woody plants and their preferences by foraging livestock in semi-arid rangeland in northern Tanzania

Bush cover is high in some semi-arid African grasslands, and these woody plants have various socio-cultural uses and potential as livestock feed resources. The current study was conducted in northern Tanzania to investigate the changes in bushland cover, identify general uses of woody plants by agro-pastoral farmers, determine livestock preferences, and the nutritional values of selected plants. We determined bush cover changes from 2000 to 2022 by Google Earth Engine using the Random Forest algorithm during land cover classification. Livestock observation and participatory rural appraisal were used to sample woody plants foraged by livestock. Farmers named woody plants in a local language, listed their uses and ranked them as livestock feed. Farmer-preferred plants were analysed for nutritional values and screened for preference using goats. Bush cover had increased by 6.9–90.2% at 0.6–4.5% per year in the studied area, where 32 woody plant species were ranked and had other socio-cultural uses. These uses were medicine (78%), firewood (59%), a food source (31%) and construction (28%), with Grewia bicolor and Cordia sinensis possessing many of the uses. Farmers ranked woody plants highly as the feed if they were available all year round, readily eaten by livestock (palatable) and led to high performance. The coefficient of preference (COP) varied (p < 0.001) among goats fed the selected plants. Grewia similis (COP = 1.8) and Haplocoelum foliolosum (COP = 1.7) were highly preferred, while Combretum campestris and C. sinensis were the least preferred. There were differences in nutritional values among key woody plants, and G. similis had the highest digestibility (59%), making it a suitable species for agroforestry. Encroaching non-invasive woody plants can be used as livestock feed or serve other socio-cultural uses; their control should be informed by participatory appraisal involving locals in semi-arid areas.

Variation in the role of the flag‐leaf in reproductive effort of semiarid rangeland bunchgrasses

AbstractUnderstanding the mechanisms underlying viable seed production of perennial bunchgrasses is critical to improving restoration and conservation success in Great Basin sagebrush steppe rangelands. We studied the effects of pre‐ and post‐anthesis flag‐leaf removal and post‐anthesis seed‐head shading on reproductive effort in two important rangeland restoration species, the exotic crested wheatgrass (Agropyron cristatum) and native squirreltail (Elymus elymoides). Flag‐leaf removal had distinct, species‐specific effects on seed filling. Pre‐anthesis flag‐leaf removal in crested wheatgrass reduced the proportion of filled seeds, while post‐anthesis removal did not. In contrast, squirreltail increased filled seed proportions regardless of flag‐leaf removal timing. Neither flag‐leaf removal treatment affected seed quality, as quantified by seed‐specific mass (in grams per square meter), which significantly reduced with seed‐head shading in both species. Seed‐head shading reduced total propagule production (unfilled + filled seeds) in crested wheatgrass but increased it in squirreltail, possibly due to our shading method protecting from seed‐head herbivory or high‐light stress. Flag‐leaf removal in the squirreltail also induced a negative shading effect on filled seed area, mass, and specific mass. These findings suggest flag leaves can modulate reproductive effort outside of seed provisioning, either by maintaining pre‐fertilized seed viability, as in crested wheatgrass, or acting as a competitive sink to the fully emerged seed‐head, as in squirreltail. Moreover, this study demonstrates photosynthetic activity by the seed‐head itself is critical to the expression of seed quality traits important to seedling establishment success of semiarid perennial bunchgrasses.

The LTAR Grazing Land Common Experiment at the Central Plains Experimental Range: Collaborative adaptive rangeland management.

Semiarid rangelands throughout the western Great Plains support livestock production and many other ecosystem services. The degree to which adaptive multi-paddock (AMP) grazing management approaches can help achieve desired ecosystem services remains unclear. At the Central Plains Experimental Range in northeastern Colorado, a management-science partnership with a diverse stakeholder group is comparing collaborative adaptive rangeland management (CARM), designed to incorporate AMP principles, to traditional rangeland management (TRM), consisting of season-long grazing during the growing season. Each treatment was implemented on a set of 10, 130-ha pastures paired by soils, topography, and plant communities to evaluate how CARM affects vegetation (composition and production), livestock production (steer weight gain), and wildlife habitat (vegetation structure for grassland birds). For the first 5 years of the experiment, CARM cattle were managed as a single herd using AMP grazing with planned year-long rest in 20% of the pastures. Relative to TRM, CARM enhanced heterogeneity in vegetation structure across the landscape, benefiting two grassland bird species. However, this came at the cost of 12%-16% lower steer weight gains in CARM versus TRM and declining populations of a third bird species of conservation concern in both treatments. Here we discuss how increased understanding of ecological and social processes during the experiment's first 5 years led to changes in the CARM treatment and management objectives during the next 5 years. We also discuss how innovations in remote sensing, environmental sensors, ecosystem modeling, social learning, and economic analyses are being integrated into and supported by the CARM experiment.

Soil multifunctionality increases after grazing abandonment in semiarid rangelands

Grazing by domestic animals is an economic activity that can alter the ecosystem structure and functioning of drylands. Some rangelands are experiencing a temporary or complete abandonment of grazing, but the effects of these practices on the ecology of drylands are poorly studied. Plant patches are recognized as fertility islands in drylands. Unvegetated inter-patches, far from being lifeless, harbor diverse soil microbial communities, habitually in the form of biocrusts. Here, we determined changes in plant, biocrust, and bare soil cover after grazing cessation over a 63-year period in Patagonian semiarid drylands. We also quantified, at microsite (2.25 m2) and plot (2500 m2) scales, temporal changes in soil multifunctionality by using four specific soil multifunctionality indexes associated with soil carbon, fertility, biogeochemical cycling, and stability. Our results indicate that biocrusts, although with low cover values, colonize new soil areas following grazing cessation, whereas bare soil cover increases at the expense of plants. We found that soil multifunctionality consistently increased with time since grazing cessation at the microsite scale, with biocrusts showing the highest multifunctionality values. We also observed that soil multifunctionality increased over time after grazing cessation at the plot scale, with bare soil and plants being more important than biocrusts due to their greater cover. Overall, our field study shows that the abandonment of grazing leads to a natural recovery of soil functioning in semiarid rangelands, with biocrusts and microbial communities of bare soils playing central roles, but at different spatial scales.

Using multisource remotely sensed data and cloud computing approaches to map non-native species in the semi-arid savannah rangelands of Mpumalanga, South Africa

ABSTRACT Semi-arid savannah rangelands are diverse environments (in terms of species) that play an important role in sustaining biodiversity and providing ecosystem services. However, the emergence of non-native species, as well as bush encroachment, are currently threatening these (semi-arid rangeland and grassland) ecosystems. The purpose of this study was therefore to map and quantify the spatial extents of non-native woody vegetation in the Kruger National Park and surrounding communal areas in Mpumalanga, South Africa. To achieve the study’s objectives, Sentinel-1 and Sentinel-2 remotely sensed data were combined and analysed using the random forest (RF) machine-learning algorithm in the Google Earth Engine (GEE) cloud computing platform. Specifically, spectral bands and selected spectral derivatives, e.g. enhanced vegetation index (EVI2), normalized difference moisture index (NDMI) and normalized difference phenology index (NDPI) were computed and used to map non-native woody vegetation. After optimizing the model combination, the classification outputs had an overall accuracy of 70%, with class accuracies such as producer’s accuracy (PA) and user’s accuracy (UA) ranging from 67% to 95%.It was shown in this study that using Sentinel-2 and Sentinel-1 data together led to better overall accuracy than using single sensor models when mapping semi-arid savannah rangelands. It was also found in this study that the overall classification accuracy of non-native (invasive) species using optical sensors was higher than in previous studies. On a free platform like GEE, it was possible to utilize advanced classification processes to fully exploit the informative content of Sentinel-1 and Sentinel-2 data.

Spatio-temporal patterns of rangeland forage nutritive value and grazer selection with patch-burning in the US northern Great Plains

Understanding how management influences forage nutritive value and grazer selection within grazing seasons is an ongoing effort for researchers and land managers globally. We used six, 65 ha pastures managed with patch-burn grazing and stocked with either cow-calf pairs (0.45–0.5 ha • AUM−1) or gestating ewes (0.4–0.48 ha • AUM-1) to explore how patterns in rangeland forage drive grazer selection in semi-arid rangeland over four summer grazing seasons at monthly intervals. We used near-infrared spectroscopy to determine nutritive value parameters from monthly forage clippings. We evaluated livestock performance as the average daily weight gains of each animal. We used mixed-effect models and ordination to compare patch and grazer types across the time-since-fire gradient and found that time-since-fire was significant for all measured variables. Cattle and sheep consistently preferred recently burned patches throughout grazing seasons. These recently burned patches typically contained available forage with higher crude protein and moisture content, lower biomass, and lower acid detergent fiber, acid detergent lignin, and neutral detergent fiber compared to intermediate time since fire patches and patches burned three years ago. Differences between patch-burn grazing with cattle and sheep were observed as additional patch contrasts for available biomass and crude protein, but grazer type and ecological site were not statistically significant factors for the nutritive value ordination. Our study indicates that patch-burn grazing is capable of imposing and maintaining heterogeneous, grazer selection, forage biomass, and nutritive value patterns desirable for heterogeneity focused land management, regardless of grazer type. These findings are especially relevant to the northern Great Plains where introduced grasses are homogenizing the structural environment of remaining rangelands. With prescribed fire currently an uncommon practice throughout the region, these findings provide a baseline of expectations for practitioners and land managers implementing patch-burn grazing and illustrate how grazing livestock can benefit from the patch contrast in forage nutritive value and biomass.

Effects of land-use intensity on vegetation dynamics across elevation in Savanna Grassland, Southern Ethiopia

The rangeland ecosystem is currently one of the area’s most sensitive to biodiversity because of both natural and human effects. There is still much to learn about the sustainable management of dry and semi-arid rangelands in order to protect their rich biodiversity resources. This is due to the uncertain indirect effects of environmental factors, such as dryness, on vegetation species, which are mediated by shifting both living and non-living components. The purpose of this project was to ascertain the effects of land use intensity (LUI) on the various species of rangeland flora along the elevation gradient in the Borana Rangeland. We gathered a total of 37 plant species, comprising 22 grasses, 7 graminoids, and 8 forbs, from the nine sampling locations, which were exposed to LUI and included three locations within each elevation range of 500–900, 1000–1400, and 1500–1900 m.a.s.l. At every sampling site, we evaluated the dynamics of the plant species, taking into account their diversity, richness, percentage of undesirable species, and properties of the soil. We used structural equation modeling (SEM) to examine the effects of LUI on the different vegetation species along the elevation gradient. We found that the density and diversity of vegetative species decreased and the fraction of undesired species increased as elevation climbed (from lower to higher). Because of the heavy livestock grazing, these impacts were substantially linked with high LUI at lower elevations. According to our research, the complex relationships between elevation gradient and LUI have a big influence on the diversity and density of the flora. This demonstrates that we need to account for environmental gradients in order to generalize LUI's effects on rangeland biodiversity. This study sheds important light on the complex interactions between vegetation dynamics and LUI in savanna grasslands. To create practical strategies for maintaining ecosystem health and biodiversity in the Southern Ethiopian Savanna Grasslands, policymakers, environmentalists, and land managers should take these findings into account.

Shrub encroachment in semi-arid rangelands of southwestern Buenos Aires, Argentina does not affect plant diversity and composition

Shrub encroachment in semi-arid rangelands is a phenomenon associated with changes in floristic composition, loss of diversity and ecosystem degradation, enhanced by inappropriate grazing practices. However, the outcome depends on the species' identity and the management carried out. The objective of this study was to evaluate shrub species dynamics and their effect on plant community composition in a Monte rangeland of Argentina, under conservative grazing management at two different working scales. During two years, ground-based vegetation and soil cover measurements were performed in patches with and without shrubs using Daubenmire and Canfield's methods. Herbaceous and woody species recorded were classified according to their functional traits and forage value. Specific richness, Shannon's diversity index and Pielou's evenness were calculated. At a larger-scale evaluation, Sentinel-2A satellite images from year 2016–2022 were classified into three cover classes to evaluate the shrub encroachment process. Although an increase in shrub presence was observed over the years at both scales no effect was found on the diversity and specific composition, nor on the occurrence of forage species. Shrub presence promotes the coexistence of species with different functional traits and creates favorable conditions for soil protection and the establishment of desirable species for livestock purposes.

Influence of different temperatures on seedling growth and development of Calobota sericea, a semi-arid rangeland species of South Africa

This study determined how temperature affected the early growth of seedlings of Calobota sericea (Thunb.) Boatwr. & B.-E.van Wyk. One-month-old C. sericea seedlings were grown at constant temperatures of 2.5, 5, 10 and 20 °C for 30 days. After 30 days the plants were removed and shoot length, root length, stem thickness, number of leaves, middle leaflet length, leaf width, petiole length, shoot fresh and dry mass, and cell membrane stability through electrolyte leakage from the leaves, and shoot water content were measured. Results showed that the optimum temperature for C. sericea seedling growth was approximately 10 °C. Significant seedling mortality was observed at 20 °C, while no mortality was observed between 2.5 and 5 °C, and less than 4% of seedlings died at 10 °C. The majority of measured morphological variables in this study increased significantly from 2.5 °C and 5 °C, reaching a maximum at 10 °C before decreasing significantly at 20 °C. Electrolyte leakage from leaves was significantly more at 2.5 °C and at 20 °C, suggesting that seedlings were more stressed at these temperatures. In conclusion, even though C. sericea has a wide optimum germination temperature range, early seedling growth requires a narrow temperature range for optimum growth and development.

A Key Interaction Behind the Scenes: Dung Beetles in Livestock Production from Arid and Semi-Arid Rangelands.

Pastoralism is a dominant agricultural activity in arid and semi-arid ecosystems. The interaction between coprophagous insects and livestock is a key but an undervalued topic in rangeland management decisions. The objective was to identify similarities and differences in the composition of coprophagous insects and nesting strategies, associated with different climatic conditions within these regions. We performed a literature review of research articles available in the Scopus database which resulted in 17 articles. We examined the taxonomic diversity of dung beetles and their nesting strategies in relation to temperature and precipitation at the study sites. Results revealed a rich and varied interaction between dung beetles and livestock in arid and semi-arid environments, with 364 species from the Scarabaeoidea superfamily documented worldwide. The greatest diversity of dung beetles was reported in hot arid and semi-arid conditions with dry winters and in cold semi-arid ones with no marked annual precipitation cycle. These insects displayed diverse nesting strategies, with endocoprid strategies predominating in colder and drier settings, and paracoprid and telecoprid strategies in warmer, more humid environments. Domestic animal species are currently key components in promoting this interaction, which indicates that the ecological processes involving coprophagous fauna are occurring in production systems, which are under the influence of human decisions. We discuss the design and planning of livestock and rangeland management in arid and semi-arid environments, emphasizing in a more formalized manner the inclusion of this kind of interaction.

Interplay between Livestock Grazing and Aridity on the Ecological and Nutritional Value of Forage in Semi-arid Mediterranean Rangelands (NE Spain)

Rangeland-based livestock production constitutes a primary source of livelihood for many inhabitants of dryland regions. Their subsistence relies heavily on maintaining the productivity, biodiversity and services of these ecosystems. Harsh environmental conditions (e.g., drought) combined with land use intensification (e.g., overgrazing) make dryland ecosystems vulnerable and prone to degradation. However, the interplay between livestock grazing intensity and aridity conditions in driving the conservation and nutritional value of forage in arid and semi-arid rangelands is still not fully understood. In this study, we performed structural equation models (SEM) to assess the simultaneous direct and indirect effects of livestock grazing intensity and aridity level on community structure, diversity, biomass, forage production, forage C:N ratio and forage fiber composition in two semi-arid Mediterranean rangelands, NE Spain. Not surprisingly, we found that higher livestock grazing intensity led to lower community plant cover, especially when combined with higher aridity. However, both increasing grazing intensity and aridity were associated with higher forage production after one year of grazing exclusion. We did not find any adverse effect of livestock grazing on plant diversity, although plant species composition differed among grazing intensity levels. On the other hand, we found an aridity-driven trade-off in regard of the nutritional value of forage. Specifically, higher aridity was associated with a decrease in the least digestible fiber fraction (i.e., lignin) and an increase in forage C:N ratio. More interestingly, we found that livestock grazing modulated this trade-off by improving the overall forage nutritional value. Altogether, our results provide further insights into the management of semi-arid Mediterranean rangelands, pointing out that maintaining traditional rangeland-based livestock production may be a sustainable option as long as rangeland conservation (e.g., community plant cover) is not severely compromised.

Soil quality and vegetation cover characteristics as influenced by diverse grazing regimes and soil disturbance histories in a semi-arid rangeland (Iran)

This study investigates the soil functioning and regeneration processes in a semi-arid rangeland subject to an eleven-year conservation grazing (CG) program within the Gonbad paired watershed in Hamadan, Iran. Five distinct sites with varying rangeland vegetation cover were selected based on differences in grazing regimes and soil disturbance histories. These sites include: CG site with Astragalus-Artemisia vegetation (CG(A-A)); CG site with Astragalus-Bromus vegetation (CG(A-B)); CG site, easily accessible to grazing livestock, with Astragalus-Lactuca vegetation (CG(EA)); CG site with a history of past rainfed farming and Centaurea-Grasses vegetation (CG(PRF)); and free grazing (FG) site with Astragalus-Euphorbia vegetation. In addition, a long-term rainfed farming site (RF) was studied as the dominant land use. Rangeland management practices had a discernible impact on nearly all soil quality (SQ) indicators. However, due to their strong interdependence, only soil aggregate stability, carbohydrates, and phosphatase activity proved to be critical indicators representing soil functioning in the area. The general SQ index illustrated a decline in soil functioning at RF (58%), CG(PRF) (55%), FG (42%), and CG(EA) (22%) sites compared to sites classified as "good" (CG(A-A) and CG(A-B)). Total organic carbon and carbon stock were only recovered in well-restored sites, characterized by a predominance of shrubs and perennial grasses. Meanwhile, active carbon and carbohydrates revealed the positive effects of conservation grazing in moderately and poorly restored sites, characterized by a predominance of forbs and annual grasses. Our findings suggest that soil disturbance history and grazing accessibility are critical factors for successfully implementing conservation grazing management in the area.

An Assessment of Plant Growth and Soil Properties Using Coal Char and Biochar as a Soil Amendment

Soil degradation due to loss of soil organic carbon is a serious concern in semiarid agroecosystems. Biochar and other organic char products have long been known to increase soil organic carbon. In this study, three-year field observations were carried out on use of coal char (CC) and biochar (BC) as soil amendments in unirrigated semiarid rangeland soil. Coal was pyrolyzed at three different temperatures of 650, 750, and 800 °C to form CC650, CC750, and CC800, respectively, and BC was obtained from a local commercial producer. Manure, CC, and BC were incorporated in soil at 10% (v/v). Analyses of plant growth (aboveground biomass) and soil properties were performed and compared with the control treatment without char. In all three years, CC applied with manure (CC650M) produced significantly greater grass biomass, by 95, 42, 101%, and BC applied with manure (BCM) increased grass biomass by 89, 39, 52% in 2018, 2019, and 2020, than the controls in the respective years. Soil tests a year after application of char indicated significantly increased soil organic matter (OM) with CC and BC treatments (1.60–2.93%) compared with the control (1.37%). However, further detailed studies are required to investigate CC and BC interactions with soil in unirrigated semiarid rangelands.