25 research outputs found
Diverging climate trends in Mongolian taiga forests influence growth and regeneration of Larix sibirica
Central and semiarid north-eastern Asia was subject to twentieth century warming far above the global average. Since forests of this region occur at their drought limit, they are particularly vulnerable to climate change. We studied the regional variations of temperature and precipitation trends and their effects on tree growth and forest regeneration in Mongolia. Tree-ring series from more than 2,300 trees of Siberian larch (Larix sibirica) collected in four regions of Mongoliaâs forest zone were analyzed and related to available weather data. Climate trends underlie a remarkable regional variation leading to contrasting responses of tree growth in taiga forests even within the same mountain system. Within a distance of a few hundred kilometers (140â490Â km), areas with recently reduced growth and regeneration of larch alternated with regions where these parameters remained constant or even increased. Reduced productivity could be correlated with increasing summer temperatures and decreasing precipitation; improved growth conditions were found at increasing precipitation, but constant summer temperatures. An effect of increasing winter temperatures on tree-ring width or forest regeneration was not detectable. Since declines of productivity and regeneration are more widespread in the Mongolian taiga than the opposite trend, a net loss of forests is likely to occur in the future, as strong increases in temperature and regionally differing changes in precipitation are predicted for the twenty-first century
Pathways towards coexistence with large carnivores in production systems
Coexistence between livestock grazing and carnivores in rangelands is a major challenge in terms of sustainable agriculture, animal welfare, species conservation and ecosystem function. Many effective non-lethal tools exist to protect livestock from predation, yet their adoption remains limited. Using a social-ecological transformations framework, we present two qualitative models that depict transformative change in rangelands grazing. Developed through participatory processes with stakeholders from South Africa and the United States of America, the models articulate drivers of change and the essential pathways to transition from routine lethal management of carnivores towards mutually beneficial coexistence. The pathways define broad actions that incorporate multiple values in grazing systems including changes to livestock management practices, financial support, industry capacity building, research, improved governance and marketing initiatives. A key fnding is the new concept of âPredator Smart Farmingâ, a holistic and conscientious approach to agriculture, which increases the resilience of landscapes, animals (domesticated and wild) and rural livelihoods. Implementation of these multiple pathways would lead to a future system that ensures thriving agricultural communities, secure livelihoods, reduced violence toward animals, and landscapes that are productive and support species conservation and coexistence
Monitoring to detect change on rangelands: physical, social and economic /policy drivers
Agents that can cause important changes in properties of biological communities are referred to as drivers. Drivers may be classed as physical, social and economic/policy, referring to their origin and mode of action. Physical drivers include environmental (weather, climate) and management (livestock grazing, prescribed burning) factors. Social drivers include attitudes and values of land mangers and the public. Economic/policy drivers refer to factors such as tax laws and environmental policies (including penalties and incentives). These drivers seldom operate independently, at similar scales, or in isolation from other drivers, and subtle interactions may confound both interpretation and response. While it is difficult to identify the impact of a specific driver on a specific biological property at a specific time, it is important to monitor changes in drivers to both predict likely impacts on ecological systems and design effective response tactics and strategies. Risk assessments, adaptive management analyses, or management by hypothesis require understanding linkages between environmental drivers and various management options on ecological properties of managed systems. Though our abilities to generate accurate predictions are currently limited, conceptual models of system response to drivers are improving. Continued incorporation and refinement of understanding and monitoring effects and interactions of different drivers will contribute to improvements in these predictive capacities. It is important to remember we are developing monitoring systems for the future, as well as for today.
Keywords: adaptive management, environmental, long-term monitoring, risk assessment
African Journal of Range & Forage Science 2004, 21(2): 115â12