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.
Tag: degradation
Interacting regional-scale regime shifts for biodiversity and ecosystem services
Current trajectories of global change may lead to regime shifts at regional scales, driving coupled human-environment systems to highly degraded states in terms of biodiversity, ecosystem services, and human well-being. For business-as-usual socioeconomic development pathways, regime shifts are projected to occur within the next several decades, to be difficult to reverse, and to have regional- to global-scale impacts on human society. We provide an overview of ecosystem, socioeconomic, and biophysical mechanisms mediating regime shifts and illustrate how these interact at regional scales by aggregation, synergy, and spreading processes. We give detailed examples of interactions for terrestrial ecosystems of central South America and for marine and coastal ecosystems of Southeast Asia. This analysis suggests that degradation of biodiversity and ecosystem services over the twenty-first century could be far greater than was previously predicted. We identify key policy and management opportunities at regional to global scales to avoid these shifts.
An Assessment of the Socio-Economic and Ecological Impacts of Environmental Changes on Rural Livelihood: A Study Across Addado, Buhodle and Northern Galkaayo of Central and Northern Somalia
The international community has long recognized desertification as a significant global social, economic and environmental problem of concern with detrimental effects on the livelihoods of people in many countries world-wide. To explore this critique, this study examined local people’s views on the causes, effect and socio-economic impact of desertification and degradation to the community. The study involved a cross-sectional survey conducted with four community categories, namely nomadic pastoralist, agro-pastoralists, villagers and Internally Displaced Persons (IDPs), from Addado, Buhodle and northern Galkaayo of central and northern part of Somalia; through questionnaire-based interviews. Descriptive statistics attribute environmental changes to negative implications of human activities on the environment: the menace of which led to a decline in forage, current loss of biodiversity and the related changes in the environment, permanent migration, increased poverty and health problems. The startling results of this study conclusively demonstrate that the challenges involve proper interventions for tree planting against desertification as well as for community empowerment through public education and formation of community based environmental associations to coordinate the overall environmental management activities and to raise public awareness.
Advances in knowledge of processes in soil–tree–crop interactions in parkland systems in the West African Sahel: A review
The’parklands’ that form the most widespread farming systems in the Sahelian zone of West Africa are farming systems in which annual crops are grown under scattered trees preserved from the natural vegetation by farmers following clearing the woodlands to make crop fields. Being mixed agricultural systems, the interactions between trees and crops have always been a key element determining the management options applied by farmers. This has also attracted the attention of scientists, with the first studies of this nature dating back to the 1960’s. A combination of field trials, observational studies and modeling has been deployed to understand soil-tree-crop interactions, including sharing of growth resources by the system components. Based on this understanding, management options have been discussed with farmers. The most common experimental designs used are transects from the base of tree trunk toward the open field, concentric zones around trees or sectors under trees where various experimental treatments are applied, depending on the objectives of the studies. Key findings disentangled the contributions of each component of the system to the island of high fertility around trees using isotopic techniques, tree effects on adjacent C4 cultivated plants and alternative C3 crops that tolerate tree shade. Tree management practices such as pruning have been tested to modify the crown architecture and the patterns of root distribution in order to improve light availability and resource use efficiency. Increases in land use intensity require more active management by farmers of tree regeneration. Despite scientific advances, there are still some methodological challenges in determining the “park effect”, the tradeoffs and synergies between and among goods and services, and how to boost the provisioning, supporting and regulating functions of such agroforestry systems. Providing such ecosystem service functions is critical in the quest for ensuring food security while achieving adaptation and mitigation goals in vulnerable environments like the drylands.
Ground- and satellite-based evidence of the biophysical mechanisms behind the greening Sahel
After a dry period with prolonged droughts in the 1970s and 1980s, recent scientific outcome suggests that the decades of abnormally dry conditions in the Sahel have been reversed by positive anomalies in rainfall. Various remote sensing studies observed a positive trend in vegetation greenness over the last decades which is known as the re-greening of the Sahel. However, little investment has been made in including long-term ground-based data collections to evaluate and better understand the biophysical mechanisms behind these findings. Thus, deductions on a possible increment in biomass remain speculative. Our aim is to bridge these gaps and give specifics on the biophysical background factors of the re-greening Sahel. Therefore, a trend analysis was applied on long time series (1987–2013) of satellite-based vegetation and rainfall data, as well as on ground-observations of leaf biomass of woody species, herb biomass, and woody species abundance in different ecosystems located in the Sahel zone of Senegal. We found that the positive trend observed in satellite vegetation time series (+36%) is caused by an increment of in situ measured biomass (+34%), which is highly controlled by precipitation (+40%). Whereas herb biomass shows large inter-annual fluctuations rather than a clear trend, leaf biomass of woody species has doubled within 27 years (+103%). This increase in woody biomass did not reflect on biodiversity with 11 of 16 woody species declining in abundance over the period. We conclude that the observed greening in the Senegalese Sahel is primarily related to an increasing tree cover that caused satellite-driven vegetation indices to increase with rainfall reversal
Linking environmental security to transboundary water governance to manage the Mekong River
Since the 1990s, as global economic development has become increasingly integrated and environmental problems have worsened, perspectives on resource management that link social and ecological problems have become more influential (Ostrom, 1990). Over this same period, understanding of security has also evolved. Driven by environmental and economic change in an interdependent world, state security considerations are expanding from the traditional focus on maintaining borders through military means to begin to include nontraditional elements of security such as ecological degradation, resource scarcity, and human well-being (Floyd & Matthew, 2013). As this broadening evolves, scholars and experts have used the phrase “environmental security studies” to capture some of these developments. Floyd and Matthew (2013, p. 2) point out that environmental security encompasses “a wide range of analytical and normative meanings and positions”. For the purposes of this chapter, environmental security represents efforts to inject interdisciplinary understanding of ecological and social concerns into international deliberations with the goal of influencing states toward more adaptive, transboundary behaviour. A major goal would be the creation and implementation of policies to reduce risk and maintain critical ecological functions while supporting human capacity to adapt to change.
The socio-economic potential of under-utilized species to small holder farmers: The case of Khat (Catha edulis) in Ethiopia
“Agriculture is an important part of Ethiopia’s economy constituting a significant proportion of it’s Gross Domestic Product (GDP) and total export earnings. The method of agricultural production inEthiopia has led to increased deforestation and degradation. In order to reverse the trend, governmentof Ethiopia together with its development partners are in search of strategies to address the situation.Among others, Agroforestry has been considered as a potential strategy that can reduce the increasingdeforestation and degradation; whilst at the same time can enhance food production and increased theincome of small holder farmers. Khat (Catha edulis), an indigenous shrub species offers the potential tobe intercropped with other food crops in an Despite its potential, limited attention has been given to itin terms of assessing its potential and profitability. The aim of this article is to assess thecompetitiveness of khat production and commercialization as a complementary source of income forfarmers in the West Shewa and East Wollega zones in Ethiopia. Three focus group discussions (FGD)with khat producers were conducted in 3 villages to obtain data for the analysis. This wassupplemented with key informant interviews with traders in order to obtain further information about itsproduction and marketing. Porters’ five forces was adopted as the conceptual framework for analysis.The results indicate that demand for khat exceeds its current supply and farmers have power todetermine the price. However, there is high level of competition among traders in sourcing from thefarmers leading to price competition among traders. The agro ecological suitability for khat productionin the area indicates that more farmers can produce it if the awareness of its market potential is created.The study concludes that khat can be promoted as a profitable crop for agroforestry practices inEthiopia.
Forest governance in DRC: an analysis from actors’ participation in REDD+ policy development
The Democratic Republic of Congo (DRC) has implemented Reduced Emissions from Deforestation and forest Degradation (REDD+), a process that requires inclusive decision making and accountability. Our research analyses the participation of policy actors in DRC by asking: (1) Who is involved in national REDD+ policy making and what is their interest in participating in core policy events? (2) What level of participation do the different political actors have in core policy events? (3) To what extent do the outcomes, of REDD+ policy events incorporate different preferences of policy actors? We found that although actors’ interest in REDD+ policy events have increased over time, their concerns have rarely been taken into account in decision-making processes. The presence of local civil society and indigenous group organizations is weak while international organizations play a major role in the REDD+ arena. REDD+ is treated as a project rather than being embedded in national politics.
Reducing forest degradation by managing bushfires in The Gambia
Key findings:
- Over 90% of bushfires in the Gambia are aggravated by human activities such as fuelwood and charcoal production, forest and farm clearing activities, pests and disease control, smoking, and increased fuel loads that accelerate fire spread
- Bushfires affect half of the Gambia forests, which are estimated at 423,000 hectares (about 47% of total land area), with 70% of them facing one or more forms of degradation
- In The Gambia, precipitation patterns are critical predictors of bushfire occurrence. Bushfires are highest during the dry and hot seasons and lowest during the rainy/wet seasons
- There is a wide human and institutional capacity gap in bushfire management in the Gambia, including an inadequate number of well-trained personnel, inadequate equipment and resources to suppress bushfires, inadequate communications and coordination on wildfire management, and lack of incentives towards preventing, suppressing and recovering after bushfires.
An assessment of recent peat forest disturbances and their drivers in the Cuvette Centrale, Africa
The largest tropical peatland complex in the Cuvette Centrale is marked by persistent knowledge gaps. We assessed recent peat forest disturbances and their direct drivers from 2019 to 2021 in Cuvette Centrale, spanning the Republic of Congo (ROC) and the Democratic Republic of Congo (DRC). Utilizing peatland maps and Radar for Detecting Deforestation alert data, we analyzed spatial and temporal patterns of disturbances. Further, we examined 2267 randomly sampled peat forest disturbance events through visual interpretation of monthly Planet and Sentinel 2A data to identify direct drivers. Our findings revealed that between 2019 and 2021, about 91% of disturbances occurred in DRC, with hotspots concentrated in the northwest Sud-Ubangi district. Disturbances predominantly followed a sharp seasonal pattern, recurring during the first half of each year with temporal hotspots emerging between February and May, closely associated with smallholder agriculture activities. Smallholder agriculture accounted for over 88% of disturbances in Cuvette Centrale, representing a leading role both in ROC (∼77%) and DRC (∼89%). While small-scale logging contributed 7% to the disturbances in the region, it constituted an important driver (18%) in the ROC. Other drivers included floods, roads, and settlements. Approximately 77% of disturbances occurred outside managed forest concessions in Cuvette Centrale, with 40% extending into protected areas. About 90% of disturbances were concentrated within 1 km of peat forest edges and ∼76% of the disturbances occurred within 5 km of road or river networks. The insights underscore the crucial need for effective peat forest conservation strategies in Cuvette Centrale and can inform national policies targeting peatland protection, aligning with commitments in the Brazzaville Declaration and the Paris Agreement. Further, our findings on direct driver assessment could serve as a reference dataset for machine learning models to automate the visual interpretation and upscale the assessment across the entire region.