桑给巴尔岛附近硬珊瑚的分布和丰度模式

东非珊瑚礁的特点是它位于一个离散的动物地理学分区[1],具有经由赤道流接纳和重新分配偏远的种属物质的潜在重要性[2].尽管如此,该地区仍然是世界上研究最少的地区之一.例如,在坦桑尼亚,尽管珊瑚礁是众多的人赖以为生的重要自然资源,却没有受到应有的重视和研究[3～5].为数不多的研究定量分析过坦桑尼亚的珊瑚礁结构[6～13],而且大部分只是限于对一些礁砰进行基线研究.     

Indicators as ‘circular argumentation constructs’? An input–output analysis of the variable structure of five environmental sustainability country rankings

This paper is concerned with the normative underpinnings of popular sustainability indicators and country rankings. Attempts to quantify national sustainability in the form of composite indicators and rankings have increased rapidly over past decades. However, questions regarding validity and interpretability remain. This article combines theoretical and statistical tools to explore how input variables in five popular sustainability indicators can be related to different theoretical paradigms: weak and strong sustainability. It is shown that differences in theoretical interpretations affect input variable selection, which in turn affects indicator output. This points towards the risk of indicators becoming a sort of ‘circular argumentation construct’. The article argues that sustainability indicators and country rankings must be treated as theoretical just as much as statistical instruments. It is proposed that making underlying normative assumptions explicit, and making input variable selection more clear in a theoretical sense, can enhance indicator validity and usability for policy makers and researchers alike.     

Building future scenarios and uncovering persisting challenges of participatory forest management in Chilimo Forest, Central Ethiopia

We examined the changes in forest status and people's livelihoods through building future scenarios for Chilimo Forest in Central Ethiopia where participatory forest management (PFM) is being implemented. Participatory methods were employed to collect data, and a dynamic modeling technique was applied to explore trends over time. By integrating the more quantitative model outputs with qualitative insights, information on forests and livelihoods was summarized and returned to users, both to inform them and get feedback. A scenario of open access without PFM provides higher income benefits in the short term but not over the longer term, as compared to a scenario with PFM. Follow up meetings were organized with national decision makers to explore the possibility of new provisions in the national forest proclamation related to joint community-state ownership of forests. Project implementers must constantly work towards improving short term incentives from PFM, as these may be insufficient to garner support for PFM. Other necessary elements for PFM to succeed include: ensuring active participation of the communities in the process; and, clarifying and harmonizing the rules and regulations at different levels.     

Inverse modeling for effective dispersal: Do we need tree size to estimate fecundity?

The estimation of the dispersal kernel for the seedling and sapling stages of the recruitment process was made possible through the application of inverse modeling to dispersal data. This method uses the spatial coordinates of adult trees and the counts of seedlings (or saplings) in small quadrats to estimate the dispersal kernel. The unknown number of recruits produced by an adult tree (the fecundity) is estimated - simultaneously with the dispersal kernel - via an allometric linear model relating the unknown quantity with a (easily) measured characteristic of the adult tree (usually the basal area). However, the allometric relation between tree size and reproductive success in the sapling (or seedling) stage may not be strong enough when numerous, well-documented, post-dispersal processes (such as safe-site limitation for recruitment) cause large post-dispersal seedling mortality, which is usually unrelated to the size of the tree that dispersed them. In this paper we hypothesize that when tree size and reproductive success in the seedling/sapling stage are not well correlated then the use of allometry in inverse modeling is counter-productive and may lead to poor model fits. For these special cases we suggest using a new model for effective dispersal that we term the unrestricted fecundity (UF) model that, contrary to allometric models, makes no assumptions on the fecundities; instead they are allowed to vary freely from one tree to another and even to be zero for trees that are reproductively inactive. Based on this model, we examine the hypothesis that when tree size and reproductive success are weakly correlated and the fecundities are estimated independently of tree size the goodness-of-fit and the ecological meaning of dispersal models (in the seedling or sapling stage) may be enhanced. Parameters of the UF model are estimated through the EM algorithm and their standard errors are approximated via the observed information matrix. We fit the UF model to a dataset from an expanding European beech population of central Spain as well as to a set of simulated dispersal data were the correlation between reproductive success and tree size was moderate. In comparisons with a simple allometric model, the UF model fitted the data better and the parameter estimates were less biased. We suggest using this new approach for modeling dispersal in the seedling and sapling stages when tree size (or other adult-specific covariates) is not deemed to be in strong relation to the reproductive success of adults. Models that use covariates for modeling the fecundity of adults should be preferred when reproductive success and tree size guard a strong relationship.     

桑给巴尔岛附近硬珊瑚的分布和丰度模式

东非珊瑚礁的特点是它位于一个离散的动物地理学分区[1],具有经由赤道流接纳和重新分配偏远的种属物质的潜在重要性[2].尽管如此,该地区仍然是世界上研究最少的地区之一.例如,在坦桑尼亚,尽管珊瑚礁是众多的人赖以为生的重要自然资源,却没有受到应有的重视和研究[3～5].为数不多的研究定量分析过坦桑尼亚的珊瑚礁结构[6～13],而且大部分只是限于对一些礁砰进行基线研究.     

The Expansion of Farm-Based Plantation Forestry in Vietnam

This study targets plantation forestry by farm households (small holders), which is increasing globally and most rapidly in China and Vietnam. By use of an interdisciplinary approach on three study sites in Vietnam, we examined the trends in farmers’ tree planting over time, the various pre-requisites for farm-based plantation forestry and its impact on rural people’s livelihood strategies, socio-economic status, income and security. The findings indicated a change from subsistence to cash-based household economy, diversification of farmers’ incomes and a transformation of the landscape from mainly natural forests, via deforestation and shifting cultivation, to a landscape dominated by farm-based plantations. The trend of transformation, over a period of some 30 years, towards cash crops and forestry was induced by a combination of policy, market, institutional, infrastructural and other conditions and the existence of professional farming communities, and was most rapid close to the industrial market.     

Just Turn on the Faucet: A Content Analysis of PSAs About the Global Water Crisis on YouTube

Water is essential for human life, yet safe drinking water is a limited resource. Critical to fighting the global water crisis are public awareness campaigns, including Public Service Announcements (PSAs). While YouTube has become a popular medium for disseminating prosocial content such as PSAs, environmental communication efforts on this platform remain largely uninvestigated. This study examines the content and characteristics of global water crisis PSAs on YouTube by applying two communication models: the Extended Parallel Process Model, and the Elaboration Likelihood Model. These models are used to evaluate the potential effectiveness of the PSAs. Content analysis reveals that threat messages often outweigh efficacy messages in the videos, central route processing cues are more prevalent than peripheral route cues, and a focus on quality or quantity issues differed by sponsoring organization (non-profit, for-profit, government). Implications and avenues for potential future research are discussed.     

Government plans and farmers intentions: a study on forest land use planning in Vietnam

In 1998, the Vietnamese National Assembly approved a Five Million Hectare Reforestation Program, (5MHRP) 1998-2010. It would increase forest cover by some 45%, use barren hills, produce wood, and generate socioeconomic development. It would, however, also put demands on Vietnamese planning. Experiences from a former development project and two case studies from a commune and village are used as a basis for analyzing the planning system. The study describes the objectives and strategies of government and farmers in one commune and one village and analyzes how planning data influence scenarios on future development. Official planning data do not reflect reality but are derived through negotiations. In the commune and village studied, it would be difficult for the 5MHRP to materialize, as most of the forest land, officially not yet used, is actually used for food production. The approach and method used by the study offers alternatives to current planning practices.