• Energy Research

Ruminant livestock production is arguably the most varied, complex, impactful, and controversial land use sector of our global food system today. Despite calls for improved sustainability across the sector, progress has been limited. To advance effective solutions, there is a need to understand livestock systems and outcomes at regional scales, grounded enough in local conditions to be relevant, yet broad enough to be generalizable for policy or funding interventions. Using a comparative qualitative analysis of ten expert-led case studies from diverse agroecological regions and production systems around the world, we offer an updated approach to categorizing livestock systems, discuss relevant outcomes, and offer insight into the key contextual factors that influence current systems and potential for change. We find that in addition to livestock production system classes, economic (local, regional, and global economics and markets), environmental (biome suitability for ruminant grazing, land condition, precipitation), and social and cultural factors (land tenure, cultural embeddedness of livestock) are important to consider. Our case study analysis also shows that livestock management is typically motivated by at least five outcomes, with priority outcomes shifting from region to region, highlighting that livestock plays different roles, with different implications, in different places. We conclude that use of a context-based lens considering multiple outcomes and perspectives will likely improve the pace of progress toward environmental and social sustainability of livestock production.

Fire and herbivory are important natural disturbances in grassy biomes. Both drivers are likely to influence belowground microbial communities but no studies have unravelled the long-term impact of both fire and herbivory on bacterial and fungal communities. We hypothesized that soil bacterial communities change through disturbance-induced shifts in soil properties (e.g. pH, nutrients) while soil fungal communities change through vegetation modification (biomass and species composition). To test these ideas, we characterised soil physico-chemical properties (pH, acidity, C, N, P and exchangeable cations content, texture, bulk density, moisture), plant species richness and biomass, microbial biomass and bacterial and fungal community composition and diversity (using 16S and ITS rRNA amplicon sequencing, respectively) in six long-term (18 to 70 years) ecological research sites in South African savanna and grassland ecosystems. We found that fire and herbivory regimes profoundly modified soil physico-chemical properties, plant species richness and standing biomass. In all sites, an increase in woody biomass (ranging from 12 to 50%) was observed when natural disturbances were excluded. The intensity and direction of changes in soil properties were highly dependent on the topo-pedo-climatic context. Overall, fire and herbivory shaped bacterial and fungal communities through distinct driving forces: edaphic properties (including Mg, pH, Ca) for bacteria, and vegetation (herbaceous biomass and woody cover) for fungi. Fire and herbivory explained on average 7.5 and 9.8% of the fungal community variability, respectively, compared to 6.0 and 5.6% for bacteria. The relatively small changes in microbial communities due to natural disturbance is in stark contrast to dramatic vegetation and edaphic changes and suggests that soil microbial communities, having evolved with disturbance, are resistant to change. This represents both a buffer to short-term anthropogenic-induced changes and a restoration challenge in the face of long-term changes.

AbstractRangelands face threats from climate and land-use change, including inappropriate climate change mitigation initiatives such as tree planting in grassy ecosystems. The marginalization and impoverishment of rangeland communities and their indigenous knowledge systems, and the loss of biodiversity and ecosystem services, are additional major challenges. To address these issues, we propose the wilder rangelands integrated framework, co-developed by South African and European scientists from diverse disciplines, as an opportunity to address the climate, livelihood, and biodiversity challenges in the world’s rangelands. More specifically, we present a Theory of Change to guide the design, monitoring, and evaluation of wilder rangelands. Through this, we aim to promote rangeland restoration, where local communities collaborate with regional and international actors to co-create new rangeland use models that simultaneously mitigate the impacts of climate change, restore biodiversity, and improve both ecosystem functioning and livelihoods.