77 resultados para rangelands communities
Resumo:
Ecological theory predicts that communities using the same resources should have similar structure, but evolutionary constraints on colonization and niche shifts may hamper such convergence. Multitrophic communities of wasps exploiting fig fruits, which first evolved about 75MYA, do not show long-term “inheritance” of taxonomic (lineage) composition or species diversity. However, communities on three continents have converged ecologically in the presence and relative abundance of five insect guilds that we define. Some taxa fill the same niches in each community (phylogenetic niche conservatism). However, we show that overall convergence in ecological community structure depends also on a combination of niche shifts by resident lineages and local colonizations of figs by other insect lineages. Our study explores new ground, and develops new heuristic tools, in combining ecology and phylogeny to address patterns in the complex multitrophic communities of insect on plants, which comprise a large part of terrestrial biodiversity.
Resumo:
Given the decision to include small-scale sinks projects implemented by low-income communities in the clean development mechanism of the Kyoto Protocol, the paper explores some of the basic governance conditions that such carbon forestry projects will have to meet if they are to be successfully put in practice. To date there are no validated small-scale sinks projects and investors have shown little interest in financing such projects, possibly to due to the risks and uncertainties associated with sinks projects. Some suggest however, that carbon has the potential to become a serious commodity on the world market, thus governance over ownership, rights and responsibilities merit discussion. Drawing on the interdisciplinary development, as well as from the literature on livelihoods and democratic decentralization in forestry, the paper explores how to adapt forest carbon projects to the realities encountered in the local context. It also highlights the importance of capitalizing on synergies with other rural development strategies, ensuring stakeholder participation by working with accountable, representative local organizations, and creating flexible and adaptive project designs.