Effects of Livestock Grazing on Vegetation Composition and Soil Moisture Properties in Grazed and Non-Grazed Range Site

Moderate grazing is the best measure to achieve the optimal conservation and soil resource utilization (case study: Bozdaghin rangelands, North Khorasan, Iran)

The study of the variability of physical and chemical factors of soil due to different intensities of livestock grazing can help in the management and maintenance of soil and vegetation. Accordingly, the effect of livestock grazing intensities on soil properties and vegetation in Bozdaghin rangelands of North Khorasan province was investigated. To investigate the effect of different livestock grazing intensities, Three 5-hectare plots in the study area were determined under different treatments (ungrazed (UG), moderate grazing (MG), and heavy grazing (HG)), and the effect of three grazing intensities on vegetation and soil physicochemical and erodibility properties (SPEP) was evaluated. The soil sampling process was performed at depths of 0-15, 15-30 cm and SPEP including soil saturation moisture (SSM), soil texture (percentage of clay, sand, and silt), absorbable potassium (K), electrical conductivity (EC), soil organic matter (SOM), absorbable phosphorus (P), acidity (pH), and bulk density were evaluated, and Soil Erodibility Index (SEI) was calculated by implementing the modified clay ratio relation. To assess the impact of various grazing intensities on all measured characteristics, multivariate analysis of variance (MANOVA) and Duncan tests were utilized to compare the means and their grouping. The results showed that HG compared to MG causes worrying consequences in the first soil depth. Also with increasing grazing intensity, plant production percentage (P < 0.05) and vegetation density (P < 0.01) decreased, and the amount of bare soil (P < 0.01) increased. Also, with increasing grazing intensity, the amount of pH, EC, clay, saturated moisture, and N decreased (P < 0.01), but the amount of silt, sand, K, P, calcium (Ca), lime, and SOM increased (P < 0.01). UG improves soil quality, MG intensity causes optimal conservation and utilization of soil resources, and HG intensity causes severe changes in rangeland soil properties. In areas with MG intensity, due to the increase of the percentage of vegetation (an increase of SOM and prevents the direct impact of raindrops on the soil aggregates) and as a result improvement of soil structure and texture, an increase of water infiltration, and decrease of runoff, and the rate of soil erodibility and water erosion, the rangeland soil decreases and results in sustainable production. This results in optimal conservation and utilization of soil resources. So to sustainably exploit and balance the conservation of biodiversity, livestock production, and soil carbon and nitrogen management, MG is recommended.

The History of Pastoral Activities in S Italy Inferred from Palynology: A Long-Term Perspective to Support Biodiversity Awareness

The present-day Mediterranean landscape is a result of the long-term human–environment–climate interactions that have driven the ecological dynamics throughout the Holocene. Pastoralism had (and still has) an important role in shaping this landscape, and contributes to maintaining the mosaic patterns of the Mediterranean habitats. Palaeoecological records provide significant multi-proxy data on environmental changes during the Holocene that are linked to human activities. In such research, the palynological approach is especially useful for detailing the complexity of anthropogenically-driven landscape transformations by discriminating past land uses and pastoral/breeding activities. This paper focuses on the palynological evidence for the impact of centuries of grazing on the vegetation of Basilicata, a region of southern Italy where animal breeding and pastoralism have a long tradition. A set of 121 pollen samples from eight archaeological sites (dated from the 6th century BC to the 15th century AD) and five modern surface soil samples were analyzed. The joint record of pollen pasture indicators and spores of coprophilous fungi suggests that continuous and intense pastoral activities have been practiced in the territory and have highly influenced its landscape. The palaeoecological results of this study provide us with better knowledge of the diachronical transformations of the habitats that were exposed to continuous grazing, with a shift toward more open vegetation and increase of sclerophyllous shrubs. The palynological approach gives insights into the vocation and environmental sustainability of this southern Italy region on a long-term basis.

Can changes to pasture management reduce runoff and sediment loss to the Great Barrier Reef? The results of a 10-year study in the Burdekin catchment, Australia

Excess sediments from agricultural areas are having a detrimental impact on the Great Barrier Reef, and threaten the long-term viability of rangeland grazing. Changes to grazing management have been promoted as a mechanism for reducing excess sediment loss from grazed rangelands. This paper summarises the results of a 10-year study (2002–11) on a property in the Burdekin catchment that investigated the role of reduced stocking rates and rotational wet season resting on hill-slope and catchment runoff and sediment yields. Ground cover and pasture biomass were evaluated using on-ground surveys and remote sensing. During this study, average ground cover increased from ~35 to ~80% but pasture biomass was low due to the dominance of Bothriochloa pertusa (77% of composition). The percentage of deep-rooted perennial species increased from ~7% of pasture composition in 2002 to ~15% in 2011. This is still considerably lower than the percentage that occupied this property in 1979 (~78%). The increased ground cover resulted in progressively lower hill-slope runoff coefficients for the first event in each wet season, but annual catchment runoff did not respond significantly to the increasing ground cover during the study. Hill-slope and catchment sediment concentrations did decline with the increased ground cover, yet catchment sediment yields increased proportionally to annual runoff due to the contribution of sub-surface (scald, gully and bank) erosion. This study has demonstrated that changes to grazing management can reduce sediment concentrations leaving B. pertusa-dominated pastures, as B. pertusa is an effective controller of surface erosion. To further reduce the runoff that is fuelling gully and bank erosion, the proportion of deep-rooted native perennial grasses needs to be increased. It is argued that more than 10 years will be required to restore healthy eco-hydrological function to these previously degraded and low productivity rangelands. Even longer timescales will be needed to meet current targets for water quality.

An investigation of management effects on range functionality (case study: Karkaboud and Kouin, Taleghan)

Ecosystem function is affected by management activities in rangeland ecosystems. Hence, it is necessary to consider management effects on rangeland ecosystem to reduce its degradation. In order to determine the effects of management activities on rangeland ecosystem, four management treatments were chosen in Taleghan, Iran. Functionality characteristics including: stability, infiltration and nutrient cycling were calculated using Landscape Function Analysis (LFA). LFA calculates these parameters using 11 soil surface indicators. Results showed that stability, infiltration and nutrient cycle were higher in Karkaboud than the other locations because of low grazing pressure and non-accessibility conditions. As grazing pressure increased we witnessed less stability, infiltration and nutrient cycling in Karkaboud cascade, Kouin and Kouin-Marjan. Main causes of decline in stability, infiltration and nutrient cycling are perennial vegetation removal, soil trampling and decrease in soil organic matter and subsequent increase in erosion and soil instability.