Forestry Mitigation Potential and Costs in Developing Countries Preface

Mitigation and Adaptation Strategies for Global Change -     

Editorial

Mitigation and Adaptation Strategies for Global Change -     

肯尼亚退化红树林港湾悬浮泥沙交换和输移动力机制

本文主要研究了肯尼亚姆瓦彻湾(属于浅潮滩红树林湿地)泥沙交换的动力机制.该港湾属于半日潮,大、小潮的潮差分别为.2m和1.4m,大潮高水位的水面面积为17km2.     

A proposed Multi Criteria Analysis decision support tool for international environmental policy issues: a pilot application to emissions control in the international aviation sector

Policy making at the level of international environmental problems appears to lack a transparent, multi criteria based, decision support ‘tool’. This is due mainly to the highly political, volatile, and contextual nature of issues at this level. The environmental problem of how to regulate emissions from international civil aviation due to their transboundary nature, and the participation of international and domestic players, makes it a ‘wicked’ international environmental problem where policy making has proved problematic. This problem has been used as the basis for developing and pilot testing a tool for contributing to international policymaking, the Multi Criteria Decision Support System (MCDSS). This tool is based on simplifying and integrating key components of Multi Criteria Analysis with a Decision Support System. A preliminary application of the tool explored three options for progressing the reduction of aviation emissions. Testing was based on the allocation of weights to environmental, social, economic and institutional categories, which were each then internally weighted to reflect key criteria in the policy process. Finally, likely performances of each option, against the criteria, were evaluated against Likert scale measures. The outputs from each of these steps were combined to generate a summed best policy option. Conclusions have been drawn and they indicate that the tool is potentially useful especially in the initial stages of policy development. The MCDSS is not an alternative to the international policy process, but rather complements, and makes explicit key tradeoffs in, that process.     

Habitat influences on reproductive allocation and growth of the mummichog (<Emphasis Type="Italic">Fundulus heteroclitus</Emphasis>) in a coastal salt marsh

To determine whether life history differences can occur in salt marsh fishes that occupy different habitats within the same marsh, we compared reproductive allocation in female mummichog (Fundulus heteroclitus) inhabiting creeks and ponds of a coastal salt marsh in southern New Jersey, USA during the spring and summer of 2001 and 2002. Females were collected in phase with the lunar spawning cycle from four sites of each habitat type, and assessed for gonad-to-body-mass ratio and growth increment. Annual reproductive allocation, expressed as a percent of somatic mass, was estimated for each site and year from the gonadosomatic indices of individuals collected during each spawning period. Mummichogs from creeks showed little change in annual reproductive allocation from 2001 to 2002, whereas those inhabiting ponds showed a significant increase between these years. Seasonal reproductive patterns indicated that pond females cease spawning at least one lunar cycle earlier than creek fish. While ponds experienced considerably higher maximum summer temperatures than creeks as well as near-anoxic pre-dawn conditions, neither of these variables explained a significant amount of variation in annual reproductive allocation. In contrast, annual reproductive allocation of mummichogs in a pond correlated with its flood frequency in both years of study. Our results suggest that while the length of the spawning season differs in mummichogs inhabiting marsh creeks and ponds, annual reproductive allocation depends more upon the hydrodynamic conditions of the particular waterbody than its habitat type per se.     

Social dynamics of juvenile marmots: Role of kinship and individual variability

Summary A population of eight juvenile female yellow-bellied marmots (Marmota flaviventris) was introduced into a marmot locality from which all other marmots were removed. Social interactions were monitored in the field and the individual behavioral profile of each animal was determined by mirror image stimulation. Social interactions were unequally distributed among the eight juveniles. Neither body size nor kinship were significantly related to frequencies of social interactions. Social interactions were significantly related to individual differences.     

A combination line transect and capture-recapture sampling model for multiple observers in aerial surveys

We present a robust sampling methodology to estimate population size using line transect and capture-recapture procedures for aerial surveys. Aerial surveys usually underestimate population density due to animals being missed. A combination of capture-recapture and line transect sampling methods with multiple observers allows violation of the assumption that all animals on the centreline are sighted from the air. We illustrate our method with an example of inanimate objects which shows evidence of failure of the assumption that all objects on the centreline have probability 1 of being detected. A simulation study is implemented to evaluate the performance of three variations of the Lincoln-Petersen estimator: the overall estimator, the stratified estimator, and the general stratified estimator based on the combined likelihood proposed in this paper. The stratified Lincoln-Petersen estimator based on the combined likelihood is found to be generally superior to the other estimators.     

A capture-recapture model with heterogeneity and behavioural response

We develop the non-parametric maximum likelihood estimator (MLE) of the full M_bh capture-recapture model which utilizes both initial capture and recapture data and permits both heterogeneity (h) between animals and behavioural (b) response to capture. Our MLE procedure utilizes non-parametric maximum likelihood estimation of mixture distributions (Lindsay, 1983; Lindsay and Roeder, 1992) and the EM algorithm (Dempsteret al., 1977). Our MLE estimate provides the first non-parametric estimate of the bivariate capture-recapture distribution.Since non-parametric maximum likelihood estimation exists for submodels M_h (allowing heterogeneity only), Mb (allowing behavioural response only) and M₀ (allowing no changes), we develop maximum likelihood-based model selection, specifically the Akaike information criterion (AIC) (Akaike, 1973). The AIC procedure does well in detecting behavioural response but has difficulty in detecting heterogeneity.     

Mineral depletion with cost as the extraction limit: A model applied to the behavior of prices in the nickel industry

This article follows papers by Pindyck and Heal and Barrow in applying a Hotelling-type depletion model to a particular resource industry: in this case that of nickel. By means of the model the resource rent per ton of nickel is calculated as the proper index of extractive resource scarcity. The time path of this resource rent indicates that the model explains industry behavior well and that, as in the two previous studies, depletion has been an important determinant of prices and rents in this industry.     

Mining of the forest and the time path of the price of timber

The paper analyzes the effect of transportation (site specific) costs and the effect of mining (depletion) of the forest on the time path of the price and of the net price of timber in two forestry models. The models differ in that one has zero costs and the other has positive costs. The analyses yield the standard mining theory results for certain cases. They also yield extentions of these results for cases with growth of the harvested trees and/or regeneration on the harvested land. The paper concludes, as one would expect, that the theory of the mine is useful in analyzing the time path of the price of timber.