Semi-arid Rangelands Research Articles

Investigating distribution of ecosystem services in rangeland landscapes: an approach based on weighted key functional traits

Abstract It is important to understand the distribution of multiple ecosystem services and their underlying basic ecological sources. In this study, a novel trait-based approach was developed to address different natural landscapes potential to supply multiple ecosystem services in three rangeland landscapes (highland, hillside and plain rangelands). First, key related functional traits and their weights for measuring each ecosystem service were determined using multi-criteria decision analysis (MCDA). Potential of each landscape to supply each ecosystem service was determined through abundance and functional values of species in providing that service. Results showed that highland rangelands had the highest potential for forage production, medical source, fuel, carbon stock, wind erosion control and water regulation. The highest potential for pollination, honey and aesthetic belonged to hillside sites. Arid plain site provided the least ecosystem services in the study region. There were significant relationships between species diversity and ecosystem services forage, medical sources and aesthetic. Richness did not represent potential of arid and semi-arid rangeland landscapes to supply multiple ecosystem services. Climate was the main factor in driving multiple ecosystem services across landscape gradient. Pearson’s correlation revealed a synergy between pollination, honey and aesthetic and they tradeoff with water regulation, carbon stock, medical source, wind erosion control. Soil fertility as a supporting service was correlated with other ecosystem services. Our approach provides useful information to identify ecosystem potential in supplying multiple ecosystem services and to assist ecological interventions for supporting multiple ecosystem services in different rangeland landscapes.

Fire effects on germination of soil seed bank in a semi-arid rangeland (a case study in Darehshahr, Ilam Province)

The size and longevity of soil seed bank in rangeland ecosystem change continuously due to natural and anthropogenic disturbances such as seed mortality, decomposition, consumption by seedivores, fire, and germination. This study aimed to examine the influence of human-induced fire on seeds germination rate in soil seed bank of a semi-arid rangeland. The study was carried out in Darehshahr, southeast of Ilam Province, western Iran in 2016 with two treatments, i.e. burned and unburned sites, in three replications. Soil samples was randomly taken at two different layers of 0-5 and 5-10 cm. Totally, 30 soil samples were taken in each soil layers at each site. Soils were spread on 15 × 20 cm sterilized sand bed and germinated seed was monitored for 3 months. Seedlings were counted every 10 days and then removed from the trays. Diversity and richness of seedling were calculated using respective indices. The Repeated Measure Analysis of Variance was used to compare the diversity and richness of seedlings. The values of the Margalef and Menhinick richness indices in the burned site were 31.12 and 25.15% greater than that in unburned site. In addition, the values of the Simpson’s and also Shannon-Wiener diversity indices in the burned site were 26.6 and 23.27% greater than that in the unburned site, respectively.

FACTORS ASSOCIATED TO GASTROINTESTINAL NEMATODES INFECTIONS IN DAIRY GOATS GRAZING ON SEMI-ARID RANGELANDS OF NORTHEASTERN MEXICO

<p>There is a lack of information about the epidemiology of gastrointestinal nematode (GIN) infections on dairy goats. The objective of this study was to evaluate factors associated with the prevalence of GIN infection in mixed-breeds dairy goat grazing on semi-arid rangelands of northeastern Mexico. Mixed-breed dairy goats (n = 668) including Boer, Nubian, Alpine, Saanen and Toggenburg in 18 flocks were used. The goats were weighted and sampled of faeces and blood. The egg counts per gram of faeces (EPG) and the percentage of packed cell volume (PCV) was determined. Age, body condition score (BCS), and FAMACHA were estimated. Environmental temperature, annual rainfall, and altitude were the independent variables. The association between EPG, PCV, BCS, and FAMACHA was determined. Temperature, rainfall, altitude, and live weight affected the EPG of GIN excretion (P <0.01). Older goats had the highest EPG counts and lower values for BCS, PCV, and FAMACHA (P <0.05) than young goats. Goats with poor BCS had a higher EPG count and lower values of PCV and FAMACHA (P <0.05). The correlations between EPG and FAMACHA; EPG and BCS; EPG and PCV were 0.58, -0.55 and -0.55, respectively (P <0.01). Correlations between FAMACHA and PCV and BCS were -0.69 and -0.66, respectively (P <0.01). It concluded, that the prevalence of infections with GIN in mixed-breeds dairy goat is high; the BCS, live weight, ambient temperature, rainfall, and altitude were factors that influence the GIN infections on dairy goats grazing on semi-arid rangeland of northeastern Mexico.</p>

A comparison of methods for detecting association between plant species

The type and significance of association between twenty-three pairs of species were detected in nine plant associations in arid and semiarid rangelands of Yazd, Iran. Six methods including L12 function, Pielou's, Dixon's and Goodall's tests, Chi square test using presence-absence data from circular quadrat and circular density-sized quadrat and four measures including Ochiai, Dice, Jaccard and Cole indices were compared to determine the type and significance of association. If a significant positive or negative association is likely to occur between two species with approximately similar density, or a significant negative association may occur between an infrequent and frequent species, the Pielou's and the Dixon's tests can provide efficient and approximately similar results and can be used with L12 function to detect the scales at which the significant association may occur. If a significant positive association is likely to occur between two species and the density of one of the species is much lower than the other, i.e., most of the individuals of an infrequent species occur in close association with a frequent species, Chi-square test and Ochiai and Dice indices using presence- absence data can be used to detect the type and significance of association. If a non-significant association exists between two species, the results of a combination of the tests may well complement each other.

Managing Grazing Intensity Linked to Forage Quantity and Quality Trade-off in Semiarid Rangelands

Knowledge of herbivory tolerance of dominant plant species and their responses to varying grazing intensity is required for sustainable grazing management in semiarid rangeland ecosystems. In a field experiment, we studied the effects of simulated grazing 0%, 30%, 50%, and 80% leaf removal (control, partial, intermediate, and heavy leaf removal) of three dominant perennial legumes: Astragalus cyclophyllon, Astragalus effuses, and Hedysarum criniferum in semiarid rangelands of southwestern Iran for 2 yr and tested 1) differential herbivory tolerance in terms of regrowth ability of belowground and aboveground biomass (AGB), fecundity, and nonstructural carbohydrate reserves; and 2) trade-off between forage quantity and quality—less defoliated plants produce larger amount of biomass with less forage quality and vice versa. The results showed a reduction in AGB and reproduction in each of the three plants. However, three forbs exhibited some sort of variations in shoot and root growth, reproduction and forage quality under intermediate and heavy leaf removal. Leaf removal in individuals of A. effusus and H. criniferum are more likely to compensate for tissue loss by allocating the available resources to the expansion of root biomass, at the cost of AGB and reproductive effort. Leaf removal also led to an increase in forage quality in each of the three forb species, depending on the level of height removal. The control plant had a higher amount of biomass production and lower amount of crude protein compared with heavy leaf removal treatments (i.e., 80%), by contrasting responses of acid detergent fiber and neutral detergent fiber, indicating a trade-off between forage quality and forage quantity. The results indicate that there is a balance among forage quantity, quality, and regrowth ability of belowground and aboveground tissues in intermediate leaf removal treatments of these forb species. This balance is used to develop principles for grazing management of steppe rangelands because such a regime meets different criteria including forage quantity, quality, and nonstructural carbohydrate reserves.

Correction to: Establishing a Suitable Soil Quality Index for Semi-Arid Rangeland Ecosystems in Northwest of Iran

There was an error in this article as originally published. The surname of coauthor Farzin Shahbazi was misspelled as “Shahbzi”. The original article has been corrected.

Estimation of spatial and temporal changes in net primary production based on Carnegie Ames Stanford Approach (CASA) model in semi-arid rangelands of Semirom County, Iran

Net primary production (NPP) is an indicator of rangeland ecosystem function. This research assessed the potential of the Carnegie Ames Stanford Approach (CASA) model for estimating NPP and its spatial and temporal changes in semi-arid rangelands of Semirom County, Iran. Using CASA model, we estimated the NPP values based on monthly climate data and the normalized difference vegetation index (NDVI) obtained from the MODIS sensor. Regression analysis was then applied to compare the estimated production data with observed production data. The spatial and temporal changes in NPP and light utilization efficiency (LUE) were investigated in different rangeland vegetation types. The standardized precipitation index (SPI) was also calculated at different time scales and the correlation of SPI with NPP changes was determined. The results indicated that the estimated NPP values varied from 0.00 to 74.48 g C/(m2·a). The observed and estimated NPP values had different correlations, depending on rangeland conditions and vegetation types. The highest and lowest correlations were respectively observed in Astragalus spp.-Agropyron spp. rangeland (R2=0.75) with good condition and Gundelia spp.-Cousinia spp. rangeland (R2=0.36) with poor and very poor conditions. The maximum and minimum LUE values were found in Astragalus spp.-Agropyron spp. rangeland (0.117 g C/MJ) with good condition and annual grasses-annual forbs rangeland (0.010 g C/MJ), respectively. According to the correlations between SPI and NPP changes, the effects of drought periods on NPP depended on vegetation types and rangeland conditions. Annual plants had the highest drought sensitivity while shrubs exhibited the lowest drought sensitivity. The positive effects of wet periods on NPP were less evident in degraded areas where the destructive effects of drought were more prominent. Therefore, determining vegetation types and rangeland conditions is essential in NPP estimation. The findings of this study confirmed the potential of the CASA for estimating rangeland production. Therefore, the model output maps can be used to evaluate, monitor and optimize rangeland management in semi-arid rangelands of Iran where MODIS NPP products are not available.

Multiple processes at different spatial scales determine beta diversity patterns in a mountainous semi-arid rangeland of Khorassan-Kopet Dagh floristic province, NE Iran

The study of local and regional mechanisms driving spatial patterns in beta diversity is essential to the understanding of biodiversity. We aimed to predict the roles of multiple mechanisms operating at regional to fine spatial scales in structuring the beta diversity in a mountainous semi-arid rangeland of the Khorassan-Kopet Dagh floristic province located in NE Iran. We evaluated the relative contributions of three main filters, at the regional (stochastic but spatially structured dispersal filter), local (abiotic filter), and fine (biotic filter) spatial scales on beta diversity across communities. We partitioned beta diversity constrained by spatial, environmental, and biotic variables in 23 communities studied here, and used simple RDA and RDA-based variation partitioning to assess the contributions of studied filters on beta diversity. Moreover, spatial autocorrelation analyses were used to test neutral theory predictions. The relative contributions of the studied ecological filters explained 55% of variation in beta diversity. Although differences in the explained variations between unique fractions are low, the abiotic and biotic filters (signifying the niche-based processes) represent stronger effects directly and indirectly (via impact on significantly of other ecological filters) than dispersal (signifying neutral processes) on beta diversity. In addition, 45% of the variation in beta diversity was not explained by the studied ecological filters. In conclusion, independent and shared impacts of processes at different spatial scales determine beta diversity in our plant communities. However, unexplained variation in beta diversity requires further study of other facets of biodiversity and community assembly processes.

Rehabilitating benefits and its sustainability of a degraded semi-arid Rangeland in Yabello Southern Ethiopia

Rehabilitating the degraded rangeland in Ethiopia is very crucial issue for improving the livelihood of pastoralist life style and the environmental sustainability of the country. In Yabello rangeland area the local communities used enclosure method in order to rehabilitate the degraded rangeland area and try to address their livelihood problems. In general the current study tried to assess the benefits obtained from the rehabilitated rangeland area from the three study site chosen through purposively techniques based on the information gathered from different aspect. Semi- structured interview, Focal group discussion was held with key informants and different stakeholders at each kebele level have been conducted to gather information from the total of 150 respondents (50 from each kebele) and analyzed both in qualitative and quantitative approaches. The result showed that the rehabilitated rangeland area mainly used to get both numerical and non-numerical benefits like livestock fattening, grazing purpose, wood cutting and charcoal production and among this livestock fatting is the major source of income across the whole study site and Dida Tuyura (A1) is the most productive site among the rest. From this we recommend that there is a need to enhance market linkages for restored rangeland products that would then drive the adoption of rangeland restoration initiatives and those helps for sustainable utilization of the rehabilitated.

Value of endemic legumes for livestock production on Caatinga rangelands

Rangelands and other native pastures occupy a large area of the planet, with greater temporal and spatial botanical composition and productivity variability. Despite the continuous and historical use of these areas, including overgrazing and fire exclusion, endemic legume species persist in some semiarid rangelands. The objective this work was to review current knowledge of legume use, especially those of the Brazilian Caatinga rangeland. Studies that measure the qualitative and quantitative variations of native legumes are essential for ruminant feed supplementation, to the sustainability of animal production, as well as for economic and environmental improvements in rangelands. Caatinga vegetation of northeastern Brazil consists of deciduous shrubs and small trees which mostly lose their leaves at the beginning of the dry season. The legume family contributes to the greatest number of endemic species but little is known about their productivity or nutritive values. Livestock select Orelha de onca [Macroptilium martii (Benth.) Marechal & Baudet] and Mororo (Bauhinia cheilantha (Bong.) Steud.) and these should, during rangeland clearing, be preserved. In addition, although Caatinga legumes have great crude protein content, their biological fixation of atmospheric N has yet to be thoroughly studied. On the negative side, some native Caatinga legumes have great levels of neutral detergent fiber-bound N (NDFN) and condensed tannin. As a result, animal performance in Caatinga is often poor, notably in the dry period. Forage legumes also provide several environmental services such as N input via BNF and rehabilitation of degraded land.

Assessing resilience to underpin implementation of Land Degradation Neutrality: A case study in the rangelands of western New South Wales, Australia

Land degradation through loss of ground cover, wind erosion and woody scrub encroachment affects rangelands globally, threatening the resilience of communities and ecosystems. Climate change is anticipated to exacerbate land degradation in the rangelands, through increased incidence of drought. In the semi-arid rangelands of Australia, land managers have limited capacity to manage land degradation. Recent Australian climate policy initiatives could provide opportunities to improve land management, and increase resilience of rangeland pastoral systems. The Australian government’s Emissions Reduction Fund enables landholders to obtain carbon credits for sequestering carbon in vegetation and soil. In western New South Wales (NSW), landholders have received funding for avoiding clearing or allowing the regrowth of native vegetation. These carbon farming projects could provide financial resources for landholders to manage drivers of land degradation and thus contribute to achieving “land degradation neutrality” (LDN). However, the impacts of carbon farming, particularly at regional level, are highly uncertain.The conceptual framework for LDN proposes that planning for LDN should be underpinned by assessment of resilience of the current and alternative lands use, using tools such as the Resilience Adaptation Pathways and Transformation Approach (RAPTA). RAPTA is a framework developed to guide the application of resilience concepts in management of social-ecological systems. It encourages a systems approach to identify critical linkages in the system, that become the focus of assessment of the system’s resilience, and development of management plans to enhance resilience, and facilitate transformation where required.We present a case study of the application of RAPTA to support assessment of the resilience of current management and alternative land use strategies involving carbon farming. RAPTA facilitated a holistic assessment of social, biophysical and economic impacts of carbon farming in western NSW, that improved understanding of the opportunities, trade-offs, synergies and risks. RAPTA was found to be an effective tool to support LDN planning. Constraints to application of RAPTA include gaps in knowledge of thresholds, and resource requirements to enable effective stakeholder engagement, to inform integrated landscape management.

Establishing a Suitable Soil Quality Index for Semi-arid Rangeland Ecosystems in Northwest of Iran

Establishing soil quality index (SQI) is a common procedure in assessing soil capacity function. Various SQIs can be designed and used in soil evaluations upon the aspects including data set, efficiency, and sensitivity. This study was conducted to distinguish a representative soil minimum dataset (MDS) among 16 total dataset (TDS) properties in semi-arid rangeland ecosystems of northwest Iran. Appropriate SQIs were calculated applying the models of integrated quality index (IQI) and Nemoro quality index (NQI). IQI by simple additive and weighted additive approaches and also NQI were calculated for both MDS and TDS based on linear transformation of soil parameters. Totally, different SQIs including simple additive IQI, weighted additive IQI, and NQI were separately established to TDS and MDS. Sensitivity index (SI) and efficiency ratio (ER) of each SQI were then calculated for prioritizing and selecting suitable index. Principal component analysis (PCA) revealed that seven indicators are appropriate MDS for accounting 70.27% of data variations. Maximum and minimum SI belonged to MDS-NQI and TDS-weighted additive IQI, with values of 2.597 and 2.056, respectively. MDS-NQI has the highest value of ER (85.71), while TDS (both weighted and simple additive)-IQI has received the lowest value of ER (71.43). Final prioritizing according to ranks of SI and ER showed that MDS-NQI is the most suitable approach in soil quality assessment of semi-arid rangelands. Therefore, it could reduce cost due to measuring fewer indicators in the laboratory on contrary premise to have more dense soil samples in the field.

Soil carbon in arid and semiarid rangelands: controlling factors

There are contested views on the effects of grazing on soil carbon. A study was done to assess the effect of grazing and other controlling factors on soil organic carbon in arid and semiarid rangelands. Five rangeland sites were selected for sampling. Each rangeland was divided into three grazing intensities: ungrazed, moderately grazed, and severely grazed. In each region, plots were randomly placed and their vegetation and environmental factors were measured. Soil samples were taken from 0- to 30-cm depths in each plot. The differences in soil carbon content between different rangeland sites and also different grazing intensities were tested. Principal component analysis (PCA) was used to determine the main environmental factor controlling soil organic carbon. The results showed significant differences between different rangeland sites in soil carbon content, although there were no significant differences between different grazing intensities. So, it can be concluded that factors other than grazing are effective on soil carbon content. The results of PCA revealed that vegetation cover, climatic factors, parental material, and elevation are the main environmental factors controlling soil carbon content in arid and semiarid rangelands.

Do soil-adjusted or standard vegetation indices better predict above ground biomass of semi-arid, saline rangelands in North-East Iran?

ABSTRACTSatellite remote sensing has greatly facilitated the assessment of aboveground biomass in rangelands. Soil-adjusted vegetation indices have been developed to provide better predictions of aboveground biomass, especially for dryland regions. Semi-arid rangelands often complicate a remote sensing based assessment of aboveground biomass due to bright reflecting soils combined with sparse vegetation cover. We aim at evaluating whether soil-adjusted vegetation indices perform better than standard, i.e. unadjusted, vegetation indices in predicting dry aboveground biomass of a saline and semi-arid rangeland in NE-Iran. 672 biomass plots of 2 × 2 m were gathered and aggregated into 13 sites. Generalized Linear Regression Models (GLM) were compared for six different vegetation indices, three standard and three soil-adjusted vegetation indices. Vegetation indices were calculated from the MODIS MCD43A4 product. Model comparison was done using Akaike Information Criterion (AICc), Akaike weights and pseudo R2. Model fits for dry biomass showed that transformed NDVI and NDVI fitted best with R2 = 0.47 and R2 = 0.33, respectively. The optimized soil-adjusted vegetation index (OSAVI) behaved similar to NDVI but less precise. The soil-adjusted vegetation index (SAVI), the modified soil-adjusted vegetation index (MSAVI2) and the enhanced vegetation index (EVI) performed worse than a null model. Hence, soil-adjusted indices based on the soil-line concept performed worse than a simple square root transformation of the NDVI. However, more studies that compare MODIS based vegetation indices for rangeland biomass estimation are required to support our findings. We suggest applying a similar model comparison approach as performed in this study instead of relying on single vegetation indices in order to find optimal relationships with aboveground biomass estimation in rangelands.

Temperature sensitivity of soil organic matter decomposition in response to land management in semi-arid rangelands of Iran

The biotic and abiotic factors can alter the temperature sensitivity of soil organic matter (SOM) decomposition in rangeland areas. This is a key issue that directly affects soil fertility and productivity. On the other hand, most of the rangelands in Iran are involved overgrazing. However, there is a lack of information about these effects, especially, in semi-arid environments. Therefore, the aim of this study was to assess the effect of land management on soil nutrient contents and their stoichiometry on the temperature sensitivity of SOM decomposition (Q10) in semi-arid rangeland ecosystems. Soil samples (at three different soil depths) were collected in adjacent rangeland areas with different management in Iran. Soils were incubated at three different temperatures. The soil heterotrophic respiration was measured using an Alkali absorption method and then was calculated Q10. The decrease in Q10 values was observed with increasing carbon (C), nitrogen (N) and phosphorus (P) of soil content. Changes of Q10 in relation to stoichiometry C:N and P:N showed a linear model and a second-order polynomial model in grazed and ungrazed rangeland respectively. Ungrazed rangeland had the lower Q10 value (0.97) compared to grazed rangeland (1.21). Labile C variability at soil due to effects in land management such as trampling and erosion, altering plant biomass and microbial communities may be able to partly explained variation of Q10 values. Overall, trend of decreasing Q10 values associated with increasing C, N and P contents of soil in all rangeland management can be explained by the high microbial CUE. The obtained results presumably indicated that stoichiometry of C:P:N can play as an important determinant in increase CUE and decrease Q10 in rangeland ecosystems. Overall, the results of this research will valuable for prediction of the condition and succession trend via Q10 and C losses in various grazing management in semi-arid rangeland ecosystems.

The impacts of season and livestock management strategy on the quality of diets selected by goats and sheep in the semi-arid rangelands of Namaqualand, South Africa

Access to good-quality forages is one of the major limitations to livestock production in semi-arid pastoral systems. This study aimed to determine whether there are differences in the nutritional quality of diets selected by herded and free-ranging goat and sheep flocks utilising Namaqualand Granite Renosterveld vegetation during the wet and dry seasons. Plant samples collected along the grazing routes of livestock were dried and analysed for their fibre, condensed tannin, total phenolic and mineral nutrient contents. The study showed that a large variety of forages were on offer and livestock groups selected different diets of which some were different to the total diet on offer. In general, significant deficiencies in phosphate, protein and energy in the diets selected by herded and free-ranging goats and sheep were observed in both wet and dry season. The quality of the diets selected by herded and free-ranging livestock was also found to be different from each other, with herded livestock generally selecting more nutrient-dense diets. Herding, therefore, allows livestock to access better-quality forage in the Namaqualand Granite Renosterveld rangeland, where it is generally poor.

Managing cow herd dynamics in environments of limited forage productivity and livestock marketing channels: An application to semi-arid Pacific island beef production using system dynamics

Sustainable ranching operations require access to adequate forage reserves and suitable means to market livestock, both of which are critical determinants of adaptive capacity (defined here as the ability to manipulate stocking rate). Ranch adaptive capacity is most relevant during times of forage shortages from drought. Unfortunately for island beef production systems, traditional adaptive measures used in continental systems are unavailable, such as transporting livestock to less affected areas, importing feed resources (cost prohibitive), intensive grazing practices or stockpiling forage (since forages mature too rapidly and are generally low quality), or destocking through cull cow sales (due to limited marketing and processing capacities). Located on an island of Hawaii, the case study ranch investigated here is challenged by each of these environmental and market constraints. The ranch resides on the leeward side of its island such that it receives minimal rainfall and forage productivity is similar to semi-arid rangelands in the western United States. The ranch's livestock management problem is compounded during drought, since island slaughter capacity is limited and there is no financially feasible means of marketing and transporting culled livestock off the island. Therefore, when forage is limited, managers are forced to retain ownership of culled mature cows, who are moved into a terminal herd to await the next available harvest or shipping availability. Terminal herds occupy areas with lower quality forages to conserve the most productive pastures for higher valued calves. This backlog of cull cows creates extended periods of stress on forage resources, since grazing pressure is not relieved as drought intensifies and increases operational expenses. A simulation model was created in an effort to identify key leverage points within the ranching operation that have the greatest impact on forage availability, herd size and net income. Upon completion of the model, sensitivity analyses were conducted to identify key drivers of model behaviors and several what-if scenarios were run based on questions provided by island ranch managers. Results showed that reducing terminal herd size through increased island processing capacity would not relieve forage pressure or eliminate the backlog of terminal cull cows, although net income was improved through greater cow sales. Several follow up tests were then run to evaluate changes to internal ranch decision making, which showed that reductions in heifer retention would provide a wider array of ecological and economic benefits. The ranch's ability to manipulate heifer retention rates, rather than cull cow rates, terminal herd shipping, or island processing capacity, was shown to be the critical aspect which drives ranch adaptive capacity.

Spatiotemporal variability of soil moisture in arid vegetation communities using MODIS vegetation and dryness indices

Among the methods devised to delineate soil and water information, optical/thermal remote sensing offers great capabilities by providing spatiotemporally multi-scale data and products like surface dryness indices. In this context, the present study utilized the MODIS-based TVDI, iTVDI, and VDI indices to scrutinize the effect of dryness on soil moisture in three vegetation communities: Artemisia spp. (sagebrush), Astragalus spp. (astragale) and grassland in central Iran during a wet (2004) and a dry year (2008). The MOD13A2, MOD11A2, and MOD09A1 products acquired on DOYs (day of the year) 97, 129, 161, and 193 were used to extract dryness and vegetation indices. The downscaled 32-day interval PERSIANN-CCS products and field-measured soil moisture were used to appraise the validity of indices. The results showed statistically significant relationships (P < .05) between iTVDI and cumulative precipitation and soil moisture in all vegetation communities and on most DOYs, suggesting iTVDI as an effective indicator to monitor dryness status. Foremost among the vegetation indices, NDVI was found as a good complementary indicator to estimate vegetation-soil moisture conditions due to exhibiting stronger linear associations with precipitation, particularly in grassland during the wet (R2 = 0.81) and the dry (R2 = 0.72) year. The lowest values of dryness indices were observed in western and southern parts of the study area. In general, it was concluded that side by side assessment of vegetation and dryness indices was a more promising approach to dryness assessment and management over arid and semi-arid rangelands.

Comparing the effects of continuous grazing and long term exclosure on floristic composition and plant diversity in rangeland ecosystems of Saral, Iran

Continuous grazing as the most common land us in Kurdistan rangeland is practiced wildly. Along with continuous grazing, long term exclosure has been implemented in research site in Saral. The main objective of this study was to investigate the changes in plant diversity, floristic composition and plant groups of the major life forms in response to 40 years of continuous grazing and long terrm exclosure in Saral rangelands, Iran. This research was conducted in cold semi-arid rangeland of Baharestan located in Saral’s agricultural and natural resources station (including grazed and excluded sites). In total, six transects were sampled in both grazed and excluded sites and ten plots were randomly placed per transect to measure vegetation and plant characteristics. Sampling was carried out in late May to early June (peak biomass) in 2017. T test was used to compare the means of total plant material, and Shannon’s diversity index was used based on the total cover percentage in both grazed and exclosure sites. Our results indicated that long-term grazing exclosure significantly increased canopy covers and species richness of annuals, perennial grasses, perennial forbs and shrubs. Conversely, continuous grazing caused some species to disappear namely Ferula haussknechtii and Prangos ferulacea. There was statistically a significant difference between litter and total plant material in experimental sites (p < 0.001). Apart from palatability, exclosure increased floristic diversity by 17.8%. Our findings elucidated that exclosure in degraded vegetation is an effective strategy and management policy to recover and restore missing vegetation cover.

Adaptation strategies to environmental and policy change in semi-arid pastoral landscapes: Evidence from Ngamiland, Botswana

Semi-arid rangeland pastoral areas have been affected by diverse pressures; livestock diseases, human-wildlife conflicts, droughts and resource scarcity as a result of fragmented landscapes that constrain pastoral livelihoods. In Botswana, pastoralists' adaptations remain insufficiently documented. Adaptation strategies are responses to livelihood constraints and if mainstreamed into development programmes can counter negative impacts arising from ecosystem deterioration. Using iterative participatory rural appraisal methods, this study examines adaptation strategies that pastoral societies in Ngamiland, Botswana have used to cope with pressures in their pastoral socio-ecological system. Findings show a move towards mixed and spatially varied livelihood strategies. Mixed agro-pastoral farming, intensification of flood recession farming, fishing and a network of self-help groups have developed over the last few decades of significant policy and environmental change. Pastoralists have become more sedentary with increases in petty trade and higher dependency on social welfare programmes. As the ability to adapt has positive attributes for livelihood sustainability and resilience, there is a need for practical initiatives that improve pastoralists' adaptive capacity, such as reforming pastoralists' institutions and expanding infrastructural development in pastoral areas so as to enable access to markets. These also include the need to share insights more widely across the district, nationally and regionally.