Factor Biases and Promoting Sustainable Development: Adaptation to Drought in the Senegal River Basin

The ongoing drought in the Sahel region of West Africa highlights the vulnerability of food-producing systems to climate change and variability. Adaptation to climate should therefore increase the sustainability of agriculture under a long-term drought. Progress towards sustainability and adaptation in the the Senegal River Basin is hampered by an existing set of social and ecological relationships that define the control over the means of production and how people interact with their environment. These relationships are sensitive to the technological inputs and the administration of food production, or the factor bias in the different policy alternatives for rural development. One option is based on state-controlled, irrigated plantations to provide rice (Oryza) for the capital, Dakar. This policy emphasizes a top-down management approach, mechanized agriculture and a reliance on external inputs which strengthens the relationships introduced during the colonial period. A time series decomposition of the annual flow in the Senegal River at Bakel in Senegal suggests that water resources availability has been substantially curtailed since 1960, and a review of the water resources budget or availability in the basin suggests that this policy's food production system is not sustainable under the current climate of the basin. Under these conditions, this program is exacerbating existing problems of landscape degradation and desertification, which increases rural poverty. A natural resource management policy offers two adaptation strategies that favour decentralized management and a reduction of external inputs. The first alternative, “Les Perimetres Irrigués”, emphasizes village-scale irrigation, low water consumption cereal crops and traditional socio-political structures. The second alternative emphasizes farm-level irrigation and agro-forestry projects to redress the primary effects of desertification.     

农林复合经营研究──桉树间种山毛豆对林木和土壤的影响

本文研究了桉树人工林间种山毛豆的适应性及其对林木和土壤的影响．结果表明，在一年生桉树人工林下，山毛豆生长正常，以后，随着林地的逐浓荫蔽，生长有逐渐衰退现象；间种山毛豆当年，可能对林木生长有一定影响，但可通过改善间种方式而消除．第二年以后对桉树生长的促进作用逐渐显著；间种山毛豆对提高土壤肥力也有一定作用，对促进林业生产的持续发展有重要意义．     

农林复合经营在农村可持续发展中的地位和作用

论述了农林复合经营的概念及内涵，现代农林复合经营崛起的历史必然性，并通过对农林复合经营在农林牧相互促进、协调发展方面，实现经济、社会、生态三大效益统一的论述，充分揭示了其在农村可持续发展中的重要地位和作用。     

川中浅丘农区坡地林农复合系统的综合评价

本文从生物量与生产力、能量转化率、营养元素利用率、价值转换效益方面对坡地林农复合系统进行了研究，并用层次分析法（ＡＨＰ）进行了综合效益评价。结果表明，复合系统与对应的对照农地系统相比，前者具有生物量、能量、营养元素、价值的积累效应和较大生物生产潜力，对辅助能、光能、营养元素利用率以及经济效益均比较好。在８个系统中，以一台地林农复合系统的综合效益为最高。     

Examples of sustainable development efforts in Costa Rica

SUMMARY

Efforts towards sustainable development are now being undertaken at all levels and the concept has increasingly entered the consciousness of the average person. For many Costa Ricans however, it is not just an abstract concept but a matter of survival as input costs increase, natural resources diminish and the soil loses fertility or is washed away. This paper reviews three case studies representing different approaches towards achieving sustainable development by different types of organization which are each innovative in preventing further destruction of tropical forest resources.     

A Small‐Scale Land‐Sparing Approach to Conserving Biological Diversity in Tropical Agricultural Landscapes

Two contrasting strategies have been proposed for conserving biological diversity while meeting the increasing demand for agricultural products: land sparing and land sharing production systems. Land sparing involves increasing yield to reduce the amount of land needed for agriculture, whereas land‐sharing agricultural practices incorporate elements of native ecosystems into the production system itself. Although the conservation value of these systems has been extensively debated, empirical studies are lacking. We compared bird communities in shade coffee, a widely practiced land‐sharing system in which shade trees are maintained within the coffee plantation, with bird communities in a novel, small‐scale, land‐sparing coffee‐production system (integrated open canopy or IOC coffee) in which farmers obtain higher yields under little or no shade while conserving an area of forest equal to the area under cultivation. Species richness and diversity of forest‐dependent birds were higher in the IOC coffee farms than in the shade coffee farms, and community composition was more similar between IOC coffee and primary forest than between shade coffee and primary forest. Our study represents the first empirical comparison of well‐defined land sparing and land sharing production systems. Because IOC coffee farms can be established by allowing forest to regenerate on degraded land, widespread adoption of this system could lead to substantial increases in forest cover and carbon sequestration without compromising agricultural yield or threatening the livelihoods of traditional small farmers. However, we studied small farms (<5 ha); thus, our results may not generalize to large‐scale land‐sharing systems. Furthermore, rather than concluding that land sparing is generally superior to land sharing, we suggest that the optimal approach depends on the crop, local climate, and existing land‐use patterns. Un Método para Reservar Tierras a Pequeña Escala para Conservar la Biodiversidad en Paisajes Agrícolas Tropicales     

Assessing the strength of climate and land-use influences on montane epiphyte communities

Epiphytes, air plants that are structurally dependent on trees, are a keystone group in tropical forests; they support the food and habitat needs of animals and influence water and nutrient cycles. They reach peak diversity in humid montane forests. Climate predictions for Central American mountains include increased temperatures, altered precipitation seasonality, and increased cloud base heights, all of which may challenge epiphytes. Although remaining montane forests are highly fragmented, many tropical agricultural systems include trees that host epiphytes, allowing epiphyte communities to persist even in landscapes with lower forest connectivity. I used structural equations models to test the relative effects of climate, land use, tree characteristics, and biotic interactions on vascular epiphyte diversity with data from 31 shade coffee farms and 2 protected forests in northern Nicaragua. I also tested substrate preferences of common species with randomization tests. Tree size, tree diversity, and climate all affected epiphyte richness, but the effect of climate was almost entirely mediated by bryophyte cover. Bryophytes showed strong sensitivity to mean annual temperature and insolation. Many ferns and some orchids were positively associated with bryophyte mats, whereas bromeliads tended to establish among lichen or on bare bark. The tight relationships between bryophytes and climate and between bryophytes and vascular epiphytes indicated that relatively small climate changes could result in rapid, cascading losses of montane epiphyte communities. Currently, shade coffee farms can support high bryophyte cover and diverse vascular epiphyte assemblages when larger, older trees are present. Agroforests serve as valuable reservoirs for epiphyte biodiversity and may be important early-warning systems as the climate changes.     

Achieving sustainable development goals through participatory forest management: Examples from South-Eastern Bangladesh

Forests managed through peoples' participation can help to achieve a number of sustainable development goals (SDGs). This paper, drawing data from four participatory forest management (PFM) projects in south-eastern Bangladesh, explored: (a) the factors that influenced the outcomes of PFM; and (b) contribution of PFM towards achieving selected SDGs. The research used observation, semi-structured household interviews, group discussions, vegetation survey and Ostromʼs design principles for data collection, Divergent forest conditions and factors in four PFM sites have had differential contribution to SDGs. Heterogeneity of user groups, insufficient coordination, absence of motivation, and land tenure conflicts had affected the attainment of SDGs. The PFM helped to achieve 9–11 SDGs comprising poverty reduction (Goal 1), improving food security (Goal 2), maintaining health and well-being (Goal 3), enhancing childrensʼ education (Goal 4), fair access to jobs and committees (Goals 5 and 10), sources of clean drinking water (Goal 6), affordable energy for cooking (Goal 7), increased household economy (Goal 8), climate change through carbon sequestration (Goal 13), forest conservation (Goal 15), and partnerships with relevant institutions (Goal 16). In order to achieve SDGs, PFM could be viewed as an integral part of government development strategies, which needs sectoral coordination and integration of relevant policies.     

Competition of the active roots of Cassia siamea Lam. and Zea mays L.(cv.Katumani Composite B) in an alley cropping trial in semi arid Kenya

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林农复合生态系统空气负离子浓度日进程比较

选择河南境内黄淮海平原主体区域的商丘市民权林场与梁园区黄河故道国家森林公园的林农复合生态系统,测定了生态系统1年内各月份的空气离子的日进程,分析其空气负离子的变化规律。结果表明：空气负离子浓度在不同林农复合生态系统中有一定差别,在系统内各点差别较小;杨树生态系统的日进程格局基本一致,表现出近似的＂U＂型,一天中的高峰值出现在09：00～10：00与17：00前后;泡桐生态系统的日进程虽然在09：00～10：00也出现高峰值,但随后表现出单调下降趋势。研究结果为林农复合生态系统生态效益计量提供基础依据。