Tag: grazing
Contribution of grazing to soil atmosphere CH4 exchange during the growing season in a continental steppe
Degradation of steppes induced by overgrazing may affect the uptake of atmospheric methane (CH4) by soil sinks. However, uncertainty is associated with the very limited knowledge of gas fluxes in rapidly degrading steppe. In this study, we investigated the effects of grazing on CH4 uptake during the growing season in three types of steppe (meadow steppe, typical steppe and desert steppe and) in Inner Mongolia, China, to quantify and compare CH4 uptake in steppe ecosystems under different grazing management conditions. The CH4 fluxes were measured using an automatic cavity ring-down spectrophotometer at three steppe locations that differed primarily in grazing intensity. The results indicated that steppe soils were CH4 sinks throughout the growing season. CH4 uptake at all sites averaged 7.98 kg CH4-C ha-1 yr-1 (ranging from 1.53 to 18.74 kg CH4-C ha-1 yr-1), of which approximately 43.8% occurred in the desert steppe. CH4 uptake in the desert steppe increased 20.4% and 51.2% compared with the typical steppe and meadow steppe, respectively. Light grazing (LG) of steppe did not significantly change CH4 uptake compared with un-grazed (UG) steppe, but moderate and heavy grazing (MG, HG) reduced CH4 uptake significantly (by 6.8-37.9%, P < 0.05). These findings imply that reducing the grazing pressure on steppe would help increase the atmospheric CH4 sinks in steppe soils. Our results suggest that HG exerts a considerable negative impact on CH4 uptake in a continental steppe. Further studies involving year-round, intensive measurements of CH4 uptake are needed.
Grazing lands in Sub-Saharan Africa and their potential role in climate change mitigation: What we do and don’t know
In 2014, the USAID project ‘Grazing lands, livestock and climate resilient mitigation in Sub-Saharan Africa’ held twoworkshops, hosted by the Colorado State University, which brought together experts from around the world. Two reportsresulted from these workshops, one an assessment of the state of the science, and the other an inventory of related activitiesin the region to date.. In this short communication we summarize the main points of the first report – The state of thescience (Milne and Williams, 2015). A second report is in preparation.
Land use/cover dynamics in northern Afar rangelands, Ethiopia
This study uses a combination of remote sensing data, field observations and information from local people to analyze the patterns and dynamics of land-use/cover changes for 35 years from 1972 to 2007 in the arid and semi-arid Northern Afar rangelands, Ethiopia. A pixel-based supervised image classification was used to map land-use/cover classes. People’s perceptions and ecological time-lines were used to explain the driving forces linked to the changes. A rapid reduction in woodland cover (97%) and grassland cover (88%) took place between 1972 and 2007. Bushland cover increased more than threefold, while the size of cultivated land increased more than eightfold. Bare land increased moderately, whereas bushy grassland and scrubland remained stable. According to accounts from local people, major events that largely explain the changes include: (1) severe droughts in 1973/74 and 1984/85; (2) increase in dry years during the last decade; and (3) immigration and increased sedentarization of pastoralists. If the present land-use/cover change were to continue, coupled with a drier climate, people’s livelihoods will be highly affected and the pastoral production system will be under increasing threat.
Analysis of the impact of management scenarios in tackling land degradation in sub-Saharan Africa: multi-criteria approach to match a problem to its potential solution
Land degradation is a serious environmental problem with widespread effect at differ- ent scales. Due to its complexity and wide geographical coverage, it is not economi- cally and technically possible to manage all areas affected. Tackling land degradation and restoring degraded landscapes thus require information on hotspots that require priority intervention. Long-term (1982–2003) satellite based vegetation greenness signal (NDVI) and rainfall data were used to analyse land productivity and identify major areas of concern in sub-Saharan Africa (SSA). Next, available literature has been consulted to identify suitable management options that can be adapted to the environmental conditions of hotspots. The impacts of the identi fi ed management and restoration options in reversing land degradation were then assessed using scenario analysis. Results show that application of conservation agriculture to restore degraded croplands can improve land productivity and food security of about 14 million people. Setting-aside degraded areas and allowing them to recover ( e.g. , through enclosures) could improve productivity of ca. 0.3 million km 2 land. However, this intervention requires designing ways of accommodating the needs of about 8.7 million people who utilise those ’marginal’ areas for cultivation or livestock grazing. The study illustrates the impact of land degradation on land productivity and the feasibility of suitable land management and restoration measures to tackle the problem. Such analyses can make an important contribution to achieving the Millennium Development Goals 1 and 7, enhancing food security without compromising ecological health and integrity.
Management intensity controls soil N2O fluxes in an Afromontane ecosystem
Studies that quantify nitrous oxide (N2O) fluxes from African tropical forests and adjacent managed land uses are scarce. The expansion of smallholder agriculture and commercial agriculture into the Mau forest, the largest montane forest in Kenya, has caused large-scale land use change over the last decades. We measured annual soil N2O fluxes between August 2015 and July 2016 from natural forests and compared them to the N2O fluxes from land either managed by smallholder farmers for grazing and tea production, or commercial tea and eucalyptus plantations (n = 18). Air samples from 5 pooled static chambers were collected between 8:00 am and 11:30 am and used within each plot to calculate the gas flux rates. Annual soil N2O fluxes ranged between 0.2 and 2.9 kg N ha- 1 yr- 1 at smallholder sites and 0.6–1.7 kg N ha- 1 yr- 1 at the commercial agriculture sites, with no difference between land uses (p = 0.98 and p = 0.18, respectively). There was marked variation within land uses and, in particular, within those managed by smallholder farmers where management was also highly variable. Plots receiving fertilizer applications and those with high densities of livestock showed the highest N2O fluxes (1.6 ± 0.3 kg N2O-N ha- 1 yr- 1, n = 7) followed by natural forests (1.1 ± 0.1 kg N2O-N ha- 1 yr- 1, n = 6); although these were not significantly different (p = 0.19). Significantly lower fluxes (0.5 ± 0.1 kg N ha- 1 yr- 1, p < 0.01, n = 5) were found on plots that received little or no inputs. Daily soil N2O flux rates were not correlated with concurrent measurements of water filled pore space (WFPS), soil temperature or inorganic nitrogen (IN) concentrations. However, IN intensity, a measure of exposure of soil microbes (in both time and magnitude) to IN concentrations was strongly correlated with annual soil N2O fluxes.
Regenerative grazing for climate, ecosystem, and human health
The brief is about the case study of two transformative land regeneration approaches developed in Africa: agroforestry and regenerative grazing management. These two approaches come together in silvopastoral systems – livestock grazing and browsing in tree-dotted grasslands – which have been ranked among the most effective carbon drawdown tools at our disposal. This was presented in COP27 in Sharm El-Sheikh, Egypt venue.
Traditional ecological knowledge-based calendar system for sustainable seasonal grazing in the Pamir Mountains
Indigenous mountain communities are on the cutting edge of environmental threats, their responses, and the preservation of traditional knowledge that ensures the harmony between the environment and sustainable resource use. In the context of seasonal grazing, a key livelihood activity in the eastern Pamir Mountains, this study aimed to document a traditional ecological calendar-like management system and scientifically validate its effectiveness. Through an ethno-ecological survey comprising focus group discussions and semi-structured interviews, we examined the variations in seasonal grazing practices based on ecological calendars. The study quantified and evaluated the indicators’ efficacy in guiding these seasonal activities by analyzing time series satellite data of Normalized Difference Vegetation Index (NDVI). Additionally, the research assessed the potential alterations required in the future under anticipated climatic scenarios (SSP126 and SSP585) using the random forest algorithm. The findings underscored the alignment between seasonal migration patterns, grazing as the primary seasonal activity, and spatiotemporal variations in vegetation phenology. Our analysis revealed that in the future local herders may need to spend more or shorter time in pastures at different elevation compared to present because of possible change in the phenology. Our findings demonstrate the high validity of this calendar system in local resource management, and with modification it would be equally important in the future under new climatic scenarios.
Seedling survival after simulating grazing and drought for two species from the Pamirs, northwestern China
For plant populations to persist, seedling recruitment is essential, requiring seed germination, seedling survival and growth. Drought and grazing potentially reduce seedling recruitment via increased mortality and reduced growth. We studied these seed–related processes for two species indigenous to the Pamir Mountains of Xinjiang in northwestern China: Saussurea glacialis and Plantago lessingii. Seeds collected from Taxkorgan, Xinjiang, had a viability rate of 15.8% for S. glacialis but 100% for P. lessingii. Of the viable seeds, the highest germination rates were 62.9% for S. glacialis and 45.6% for P. lessingii. In a greenhouse experiment, we imposed a series of stressful conditions, involving a combination of simulated grazing and drought events. These had the most severe impact on younger seedlings. Modelling showed that 89% of S. glacialis mortality was due to early simulated grazing, whereas 80% of P. lessingii mortality was due to early simulated drought. Physiological differences could contribute to their differing resilience. S. glacialis may rely on water storage in leaves to survive drought events, but showed no shifts in biomass allocation that would improve grazing tolerance. P. lessingii appears more reliant on its root system to survive grazing, but the root reserves of younger plants could be insufficient to grow deeper in response to drought. After applying all mortality factors, 17.7 seedlings/parent of P. lessingii survived, while only <0.1 seedlings/parent of S. glacialis survived, raising concerns for its capacity to persist in the Pamirs. Inherent genetic differences may underlie the two species’ contrasting grazing and drought responses. Thus, differing conservation strategies are required for their utilization and protection.
Evaluating woody species composition and regeneration in controlled and free grazing systems for scaling up agroforestry in the highlands of northern Ethiopia
Understanding the performance of agroforestry woody species in controlled and free grazing systems is crucial for scaling up agroforestry practices. The objective of this study was to identify and evaluate the determinants of agroforestry woody species composition and regeneration in free and controlled grazing systems in the Ethiopian highlands. Household and field surveys were conducted on 83 and 171 households selected from controlled grazing (CG) and free grazing (FG) systems, respectively. Woody species performance was compared between the two grazing systems using independent T-test. Seemingly unrelated regression (SUR) was used to identify the factors determining woody species density/abundance, diversity and regeneration. Most trees were grown for fuel wood and timber rather than for fodder. CG users owned more diversified species and abundant regenerates and mature trees/shrubs than FG users. The SUR results showed that herd size, farmland size, fencing, plantation of seedlings, education, wealth, grazing system, farmland distance from homestead and slope were the major factors affecting the composition and regeneration of species. Specifically the SUR results per-household indicated that woody species regeneration was highly affected by grazing system. Fencing is the common underlying factor positively affecting species diversity, regeneration and density of mature trees. Homestead distance from road and number of planted seedlings significantly affected density of regenerates and mature trees. Density of mature trees and species diversity were significantly affected by agroecology and slope. Woody species diversity was significantly affected by education, wealth, farmland size and project participation. Our findings revealed that the scaling up of woody species in agroforestry requires not only CG and favorable agroecology but also matching of agroforestry options with household and farmland characteristics.