为了确定影响农田生态系统固碳能力的影响因子,在收集2000—2006年鲁西南地区农业生产统计数据的基础上,分析了该地区农田人为能量投入现状,并利用回归和逐步回归的方法研究了鲁西南地区人为能量投入对农田生态系统净初级生产力(NPP)的影响。结果表明:鲁西南地区农田人为能量投入中农膜的投入逐年增加,由2000年的14.6 kg/hm2增长到2006年的20.5 kg/hm2;化肥投入相对稳定(1200~1300 kg/hm2),但总量仍增加;农药的投入呈先增加后降低的趋势,2004年达到最高(11.03 kg/hm2);排灌机械、农用车辆的投入呈增长趋势,而单位面积劳动力的投入不断下降,2006年与2000年相比约减少0.65人/hm2。该地区农田生态系统NPP存在着东高西低的空间分布格局,历年均以东部(枣庄、济宁)高,平均NPP分别为616 g C/(m2?a)和588 g C/(m2?a),西部(菏泽)低,仅有448 g C/(m2?a);年际间呈现一定的波动性,但整体呈上升趋势。该地区农田NPP主要受人为能量投入的影响而与温度和降水的关系不大。单位面积化肥使用量、单位面积农膜使用量和农田灌溉比例在逐步回归模型中可以解释本区农田NPP方差的74.6%。因此,化肥、农膜、有效灌溉比等人为能量投入是影响该地区农田NPP提升的主要因素。 相似文献
Payments for environmental services (PES) are conservation instruments in place in various Latin American countries. They are generally undergoing adjustment and implementation changes, and they are widely implemented in indigenous communities. This article aims to suggest a relevant group of context variables in PES implementation. Characterizing the local context of two indigenous communities located in Oaxaca, Mexico, and analyzing the relationship between the local context and PES implementation and outcomes perceptions.
The work is based on 75 surveys administered to beneficiary families of the instrument in the two localities. The results suggest three conclusions:
The pertinence of the nine focal variables: “Forest cover, Opportunity costs, Livelihoods, Trust and cooperation, Motivations toward conservation, Management practices, Internal organization, Land tenure and Rules for the management and use” to the characterization of the local context. And the relevance of the new focal variable “Presence and experience with Civil Society Organizations”.
The coincidence between the contextual variables and the determinants of the success of conservation instruments.
Finally, the incidence of “Trust and cooperation” and “Internal organization” in the implementation of equitable PES schemes. And the importance of linking sustainable production to PES conservation schemes. 相似文献
Abstract Bioprospecting has had a bumpy ride over the last twenty years. High expectations for bioprospecting peaked in 1991 when Costa Rica's INBio program reached a signature deal with Merck Pharmaceuticals. But hopes have waned as bioprospecting has yielded few promising compounds and little in the way of conservation benefits. This paper examines the potential for bioprospecting to contribute to conservation efforts, both broadly and within the specific context of Panama. Today, global markets for bioprospecting services stand at an estimated $60 million per year. A new model for bioprospecting, exemplified by Panama's ICBG project, may be emerging, one that takes a more business-oriented approach to finding drugs. By using ecological insights to guide sample collection, monetizing compounds earlier, and leveraging institutional clout, ICBG Panama may be increasing its odds of scientific success and contributing to conservation in non-monetary ways. I argue that in addition, ICBG Panama, its funders, and other bioprospectors must increase the scale of their operations if they are to create sustainable entities in the Darwinian world of drug discovery. Finally, I make specific policy recommendations for improving the supply and demand of bioprospecting in Panama and globally. 相似文献