Habitat selection of endangered and endemic large flying-foxes in Subic Bay, Philippines

Large flying-foxes in insular Southeast Asia are the most threatened of the Old World fruit bats due to high levels of deforestation and hunting and effectively little local conservation commitment. The forest at Subic Bay, Philippines, supports a rare, large colony of vulnerable Philippine giant fruit bats (Pteropus vampyrus lanensis) and endangered and endemic golden-crowned flying-foxes (Acerodon jubatus). These large flying-foxes are optimal for conservation focus, because in addition to being keystone, flagship, and umbrella species, the bats are important to Subic Bay’s economy and its indigenous cultures. Habitat selection information streamlines management’s efforts to protect and conserve these popular but threatened animals. We used radio telemetry to describe the bats’ nighttime use of habitat on two ecological scales: vegetation and microhabitat. The fruit bats used the entire 14,000 ha study area, including all of Subic Bay Watershed Reserve, as well as neighboring forests just outside the protected area boundaries. Their recorded foraging locations ranged between 0.4 and 12 km from the roost. We compared the bats’ use to the availability of vegetative habitat types, riparian areas, and bat trees. The fruit bats’ locations showed a preference for undisturbed forest types and selection against disturbed and agricultural areas. Bat locations also showed selection for particular fruiting/flowering bat trees. The bats showed strong preference for riparian areas; locations were in riparian areas over four times more than expected. From these results we recommend that management focus flying-fox conservation efforts on undisturbed forest and riparian areas.     

Conservation of seed-dispersing migrant birds in Mediterranean habitats: Shedding light on patterns to preserve processes

Migratory frugivorous birds disperse the seeds of many plant species, forming mutualistic associations that render frugivores a priority for conservation in many habitats worldwide. We analysed the distribution of seed-dispersing frugivorous passerines in southern Spain, which is an important area for the conservation of European birds during winter. Frugivorous birds showed similar regional abundance and richness during four winters, although fruit availability changed among years. However, the spatial distribution of frugivorous birds in the area changed among years. These changes were principally determined by annual variation in the distribution of fruits in the area, revealing a clear ability of birds to track the distribution of fruits. The unpredictable distribution of fruits each year suggests that regional fruit crops, rather than selected habitat patches, need to be protected for the long-term conservation of frugivorous bird populations in wintering grounds. Remarkably, the distribution of frugivores was independent of forest development or general cover of shrubs, which helps to reconcile the protection of fruiting shrubs with forest cleaning, an usual management to prevent devastating summer fires that is destroying fleshy-fruited plant communities in many areas of southern Spain. Thus, leaving a part of the fruiting shrubs untouched when cleaning forest undergrowth will allow the settlement of frugivorous birds. Interestingly, both abundance and richness of frugivores decreased with elevation, probably as a consequence of impaired climatic conditions at high altitude, revealing the importance of lowland shrublands as wintering grounds for frugivorous birds. These habitats deserve special conservation efforts, as they are seriously threatened by the ongoing encroachment of agricultural and urban areas along the Mediterranean coasts.     

Landraces in central Italy: where and why they are conserved and perspectives for their on-farm conservation

Four hundred and twenty-seven landraces belonging to different plant species (forages, cereals, pulses, garden crops and fruit trees) were found on-farm in central Italy during exploration and collecting missions carried out since 1981. Open field crops are mostly grown under modern agricultural techniques by relatively young farmers on quite large farms for Italian standards. Garden crops are mostly grown by elderly farmers, running small farms or home gardens and using traditional farming systems which include the use of mechanical tools for soil preparation and occasionally the use of chemical fertilisers. There is no unique situation in on-farm conservation and management in the investigated area: the main factors involved appear to be a fragmented habitat and the presence of relatively elderly farmers. Most landraces are directly used by farmers' families, but a part is sold at local and wider markets. The main reasons why these landraces have been maintained on-farm are: their resistance/good productivity under difficult or harsh climatic conditions, traditional reasons or organoleptic peculiarities, which make them highly valued and expensive on the local and city markets and/or simply because they are appreciated by the families. Three example cases of effective on-farm conservation are presented. Social problems seem to be the main cause of genetic erosion. Perspectives and constraints to on-farm conservation and management are briefly discussed.     

山地农业与水土保持相关产业的地位和配置

牧草业开发的生态经济性、粮食生产的战略性和林业建设的生态性 ,决定了这些行业在山区农业经济中的地位和发展方向。山区生态环境建设应从区域生态资源实际出发 ,按照林草建设疏林化 ,粮果生产梯田化 ,刈割草场轮作化 ,森林利用畜牧化 ,水土保持产业化的战略原则和技术要求 ,镶嵌配置。达到山区生态环境建设和经济开发相结合 ,这是实现山地农业和水土保持事业健康发展的重要途径     

北京平原区粮菜林三地类时空转变特征

该文利用遥感与地理信息系统技术研究北京平原区农用地内部粮田、菜地和林地三大类农地利用类型的变化。结果表明:2004年至2014年这10 a间,粮田转变为林地与菜地是北京平原区农地利用变化主流。粮田转变为林地面积是969.97 km~2,其土地利用变化重要性指数高达72.11%,在各类农地利用变化类型中居首。而粮田转为菜地则主要是粮田转变为设施菜地,10 a间粮田转变为设施菜地面积是163.53 km~2,其土地利用变化重要性指数为12.16%,在各类农地利用变化类型中居次;同时,10 a间北京平原区农地利用变化存在空间分异特征。主城近郊区与远郊平原区农地利用变化主要是粮田转为林地,两大分区中该变化类型土地利用变化重要性指数分别为84.18%、76.21%,明显高于其他农地利用变化类型土地利用变化重要性指数。在城市新区,粮田则分别转为林地与设施菜地;10 a间北京平原区农地利用空间分布均具有圈层特征,由近郊向远郊,农地内部结构都呈现林地为主类型,到粮田、菜地与林地混合利用类型,再到粮田与林地组合利用类型的空间格局。而10 a间随着主城区的外扩,上述农地利用圈层特征出现了由近郊向远郊外移、且林地与蔬菜面积占比增加的现象。研究认为:农地内部粮、菜、林3地类的转变和农地利用圈层外移是农户追求经济效益最大化与政府为改善生态环境所致;而改善生态不应以牺牲粮田为代价,应充分利用粮田的生态系统服务功能以实现生态绿化目的。     

The role of remnant trees in seed dispersal through the matrix: Being alone is not always so sad

Remnant trees within the non-forest matrix are common structures of forest landscapes which have high conservation value due to their supposed roles as biological legacies and stepping stones in fragmented forest scenarios. Fleshy-fruited remnant trees are dispersal foci for many forest plants, as seeds accumulate under their canopies after visitation by forest frugivores. Despite this recognized effect, little is known about the relative role of remnant trees in maintaining their seed dispersal function after forest fragmentation. In this work, conducted in the Cantabrian Range (Northern Spain), seed deposition by frugivorous birds and post-dispersal seed predation by rodents were compared beneath the canopies of hawthorn (Crataegus monogyna) trees scattered in the non-forested matrix, to those embedded in forest patches. We studied two years which had strong differences in community-wide fruit abundance (high in 2004, and low in 2005). Hawthorn and holly (Ilex aquifolium) seeds dominated the seed rain. The density of dispersed seeds differed between years and tree type, with higher values under patch trees relative to remnant ones. However, the effect of tree type depended on both the year and the seed species, as larger differences were found in the year of high fruit availability, and with holly seeds. Higher levels of post-dispersal seed predation on holly seeds also contributed to offset the differences between tree types. Our results suggest that remnant trees, by functioning as dispersal foci, facilitate the dispersal of the two most abundant plant species for forest succession through the matrix. More importantly, we demonstrated that in years of low fruit availability in which forest frugivores are forced to exploit scattered fruit resources, the role of remnant trees may even be equivalent to that played by forest trees.     

Maintaining soil fertility under increasing land use pressure in the Middle Mountains of Nepal

Abstract. Nepal is facing a serious problem of being unable to maintain soil fertility in agriculture and forestry. Land use practices initiated over the past 10–15 years have resulted in insufficient nutrient inputs, while biomass use and production have increased. Changes in forest soil fertility have resulted from intensive use of forest biomass for animal feed and collection of forest litter for use in agriculture. The agricultural fertility changes have resulted from intensifying annual crop rotations from 1.5 to 2.5 crops and insufficient inputs. The removal of biomass from the forest has curtailed the natural organic cycle by virtually eliminating nutrient inputs.
The soils are very acidic and have little C, N, P and exchangeable bases, but have large amounts of active iron. Basic nutrients are not sustained in agriculture and differences in inputs and management between irrigated and rainfed agricultural systems are becoming visible. Irrigated fields show the largest cation content because of input from irrigation water. Rainfed agricultural sites, which receive the most nutrients (fertilizers and manure), have the highest pH values and C and N contents. All soil fertility conditions are marginal and put into question the long-term sustainability of current levels of production. Alterations in the cropping intensity are needed and the introduction of nitrogen fixing trees and crops seems to be the most viable option towards sustainability.     

Green labelling,sustainability and the expansion of tropical agriculture: Critical issues for certification schemes

The expansion of agricultural plantations at the expense of forest drives dramatic losses of biodiversity and carbon. Consumers are now demanding sustainability in tropical agriculture and producers are responding with questionable certification standards. Many certification schemes—including those for oil palm, soy, sugar cane and cacao—rely upon the High Conservation Value (HCV) concept to prevent unacceptable losses of biodiversity to agricultural conversion. This concept protects very rare species or habitats, exceptional concentrations of wildlife, or large landscape-level areas of forest. Yet much biodiversity persists below these thresholds yielding the spectre of unsustainable conversion of forest to certified plantation crops under a green label. To meet more rigorous standards of sustainability, tropical plantations would have to retain large patches of native forests in the matrix. We highlight six critical areas in need of consideration by conservation scientists, practitioners and certification processes. In particular, the application of HCV to sustainable agricultural development at the national-level, the use of Imperata grasslands and abandoned agriculture, the creation of Biobanks, and increased price premiums for certified crops could redound to the long-term protection of tropical biodiversity.     

A comparison of orang-utan density in a logged and unlogged forest on Sumatra

Several studies have shown that there is a strong decline in orang-utan densities shortly after logging. Nevertheless, there is little information on whether orang-utan densities return to their pre-logging values when logged forest is left to recover. This study investigates the orang-utan density in a 22-year-old selectively logged forest and compares it with the orang-utan density in a nearby ecologically similar primary forest. The results show that the orang-utan density did not differ significantly between primary forest and the selectively logged forest. Since we found no difference in fruit availability between the selectively logged and primary forest, we suggest that the selectively logged forest regenerated sufficiently well to sustain pre-logging levels of orang-utans. This study confirms previous studies that suggest fruit availability is the best ecological predictor of orang-utan densities and found a positive overall correlation between orang-utan density and fruit availability. The food attraction hypothesis, which explains local fluctuations in orang-utan density as a result of variation in fruit availability, was not supported.     

Land‐use and cover changes (1988–2002) around budongo forest reserve,NW Uganda: implications for forest and woodland sustainability

Land‐use and cover changes around Budongo Forest Reserve (BFR) were analysed from multi‐temporal LandSat images (1988 and 2002) and associated field‐based studies in 2003–2004. Three major land‐use and cover classes: forest/woodland, sugarcane plantations and grassland/shifting‐cultivation/settlements were clearly discriminated. The area under sugarcane cultivation increased over 17‐fold, from 690 ha in 1988 to 12729 ha in 2002, with a concomitant loss of about 4680 ha (8·2 per cent) of forest/woodland, mainly on the southern boundary of BFR. Land‐use and cover changes were a result of (a) agricultural expansion, (b) increasing human population, exacerbated by large influxes of refugees, (c) conflicts of interest and political interference in the management of BFR and (d) unclear land tenure. Agriculture is the main land‐use practice and source of income to local people, with commercial sugarcane and tobacco as the primary cash crops. Individual smallholder sugarcane plantations covered distances ranging from 30 to 1440 m along the BFR edge, with no buffer zone, resulting in direct conflicts between farmers and forest wild animals. There is an ever‐increasing need for more land for agricultural expansion, resulting in continued loss of forest/woodland on private/communal lands and encroachment into BFR. This unsustainable agricultural expansion and the local people's perception of BFR as an obstacle to agriculture, threatens the conservation of its threatened wild plants (e.g. Raphia farinifera) and the endangered chimpanzees. Therefore, their sustainable management for both development and conservation will require strong and incorruptible institutions that will seek a balance between resource exploitation and conservation. Copyright © 2008 John Wiley & Sons, Ltd.     

近20年海南省耕地林果化的时空分异及驱动因素分析

耕地林果化是指原本种植粮食作物的耕地被用于植树种果的现象,揭示耕地林果化时空分异及驱动因素对科学管理耕地、稳定粮食生产具有重要意义。基于土地类型变化视角,以海南省2000、2010和2020年3期土地利用数据为基础,综合利用转移矩阵、地理探测器和多元线性回归模型,系统分析了近20年海南省土地类型变化视角下的耕地林果化利用总体态势、时空分异特征及其驱动因素。研究表明：2000－2020年海南省林果化耕地规模呈降低态势,耕地林果化增量规模从2000－2010年的1 314.35 km2下降到了2010－2020年的472.45 km2,且前时段的林果化耕地有397.61 km2在后时段转回为了耕地。两个时段内,市县尺度耕地林果化利用现象空间差异明显,文昌、儋州的耕地林果化规模较高;网格尺度的耕地林果化空间分布格局基本相似,但格网耕地林果化比例具有明显差异。各时段驱动因子的解释能力不同,GDP增速、自然地形、区位因素是解释力较强的驱动因子;驱动因子是通过因子间交互作用影响耕地林果化利用,表现为双因子增强或非线性增强。     

Hedgerows in an agri-natural landscape: Potential habitat value for native bees

Recent declines in North American honeybee populations have highlighted the importance of native bee conservation, and the need for research on the ecological requirements of native bees in farmland. In this study, we investigated the value of hedgerows as foraging habitat for native bees in mosaics of small-scale agriculture and natural vegetation in two riparian landscapes in southeast Arizona, USA. In the summers of 2002 and 2003, we surveyed bees and flowers in four habitats: hedgerows, agricultural fields, woodlots, and native woodland. We asked: (1) How do hedgerows compare to other available habitats in bee abundance and species richness? (2) How does bee species composition in hedgerows compare to species composition in agricultural fields and woodland? (3) How do flower resources in hedgerows compare to those in fields and woodland?We found that hedgerows were attractive foraging habitat for native bees, especially in early summer, when hedgerows tended to have higher species richness than other agricultural or natural habitats. Cumulative species richness was highest in agricultural fields, although cumulative species richness did not significantly differ among fields, hedgerows, and woodland. While bee faunas overlapped among habitats, bee assemblages in hedgerows were more similar to those in woodland than to those in fields. The hedgerow herbaceous flora was roughly intermediate to that of fields and woodland; hedgerows also supported high densities of woodland-characteristic shrubs. These flowering shrubs were important in attracting bees that were otherwise uncommon in the landscape, including some species that are potentially valuable pollinators of agricultural crops.     

试论我国水土保持学科的性质与定位——川陕“长治工程”中期评估考察的思考

 以小流域为单元实施山、水、田、林、路、渠综合治理的理论与技术体系是在我国水土保持长期生产实践和科学研究中形成的具有中国特色的水土保持学科体系。通过川陕"长治工程"中期评估考察,分析"长治工程"小流域综合治理的特色与创新,并据此讨论我国水土保持学科的性质与定位。水土保持学科无论从法律地位还是学术地位,均应归属于资源保护与利用的范畴,与环境保护和生态学科的本质区别在于,水土保持更具有突出的生产功能。现阶段水土保持学科仍应首先赋予其防治水土流失,治理江河,提高农业生产综合能力,发展农村经济,改善农村基础设施及农民生活质量的内涵,并努力使之与农村生态建设结合,以不断深化和丰富其内涵,同时应在开发建设项目水土保持、饮用水水源地水土保持等方面拓展其学科外延。     

韩城市花椒护埂调查研究

<正> 韩城市山塬地区的群众,在地埂上栽花椒,以椒促农,农椒互补,粮椒双丰收,使群众走上了脱贫致富的道路,为我省在地埂利用方面树立了一面先进旗帜。为了总结推广他们的经验,我们组织地、市有关部门的同志深入实地作了大量现场考察,并和有关领导、行家进行了座谈,查阅了资料。经过分析研究,认为该市的花椒护埂,方向正确,经验丰富,规模宏大,集中连片,效益突出,在治理水土流失、建设生态环境、增加群众收入方面有很大突破,值得大力推广。最近,有关部门组织专家鉴定,韩城花椒护埂获得“全国领先水平”的高度评价。     

稀土农用的经济效应和环境生态效应

从农业经济效应和环境生态效应二方面,论述了稀土肥料促进作物生长、发育,提高作物产量,改善作物品质的效应与机理;影响土壤区系中微生物种群数量和土壤脱氢酶、碱性磷酸酶、脲酶及蔗糖酶的功能,继而反馈调节作物生长;缓解酸雨、紫外辐射和重金属伤害作物的生态生理学效应;并以稀土在作物体内分布与富集规律为参考,探讨了稀土农用的安全性。实践证明,稀土农用只要严格控制剂量就能实现增强作物抗逆性和提高作物经济效益的目标。     

紫色土丘陵区坡耕地退耕对水土流失的影响及其效益评价

 认识退耕对水土流失的影响,对耕地利用结构的调整和评价退耕还林还草的水土保持效益具有重要的科学意义。在中国科学院盐亭紫色土农业生态试验站通过2年(2003—2004年)的小区试验,观测了紫色土坡耕地种作物(小麦-玉米)、饲草(黑麦草)、果树(枇杷)和“果树+饲草”这4种模式的水土流失状况,并用层次分析法等对其水土保持效益进行了综合评价。观测结果表明:坡耕地退耕种草和种“果树+饲草”这2种模式,较作物模式显著减少水土流失超过30％,其中“果树+饲草”模式的侵蚀量减少60％以上。同时发现,退耕地如果只种果树,水土流失量反而多于种作物地,揭示了控制水土流失的关键之一是提高地表盖度。效益分析结果表明,4种模式水土保持综合效益的大小次序是:“果树+饲草”>饲草>作物>果树。     

Allocation of hunting effort by Amazonian smallholders: Implications for conserving wildlife in mixed-use landscapes

Most tropical forest landscapes are modified by humans, but the effects of these changes on rural hunting patterns and hunted vertebrate populations remain poorly understood. We investigated subsistence hunting patterns across a highly heterogeneous landscape mosaic in the Brazilian Amazon, where hunters from three villages had access to primary forest, active and fallow agricultural fields, and active and fallow Eucalyptus plantations. Landscape composition and the areas used by hunters were defined using a remote-sensing approach combined with mapping. We quantified hunting effort accounting for the availability and spatial distribution of each habitat. Overall, 71% of the kills were sourced in primary forest, but hunting in primary forest, which was often combined with other extractive activities (such as Brazil nut harvesting), yielded the lowest catch-per-unit-effort of all habitats. Hunting effort per unit area was highest in fallow fields, followed by primary forest, and both of these habitats were over-represented within village hunting catchments when compared to the composition of the available landscape. Active and fallow fields sourced a limited number of species known to be resilient to hunting, but hunting had additional benefits through crop-raider control. In contrast, hunting pressure in active and fallow plantations was low, despite a high catch-per-unit-effort, presumably because there were limited additional benefits from visiting these habitats. These results indicate that large-scale tree plantation and forest regeneration schemes have limited conservation potential for large vertebrates, as they support few forest specialists and fail to attract hunters away from primary forest.     

林农间作模式下和田绿洲特色林果结构遥感信息提取

实时准确地获取林农间作模式下的果树结构信息对推进新疆特色林果业的提质增效，增加农民收入，稳定脱贫攻坚成果，实现乡村振兴具有重要意义。该研究以新疆和田绿洲林农间作区为研究对象，提出一种综合高分遥感数据的纹理和光谱特征以及中分遥感数据的时序物候特征的果树提取方法。基于GF-2遥感数据利用面向对象方法提取高分辨率的林田地块空间信息；基于多时相Sentinel-2遥感数据构建植被归一化指数（Normalized Difference Vegetable Index，NDVI）时间序列产品，并依据果树物候特征建立决策树模型，提取间作核桃、纯核桃、枣树和葡萄4种类型；最后将多时相的分类结果与高分的林田地块叠加，获取和田绿洲特色林果作物分布信息。该方法对2020年和田绿洲核桃、枣树和葡萄提取结果的用户精度和总体分类精度均在90%以上，Kappa系数为0.95，能够满足县市级尺度的林果遥感监测精度需求。基于遥感提取的和田绿洲主要林果作物面积为4.28×105 hm2，以核桃（间作和纯核桃）为主，间作核桃面积占比63.80%，其次为枣树（19.38%）和葡萄（3.30%）。该方法可为林农间作立体种植模式下的果树类型和面积精确信息提取研究提供参考和借鉴。     

对三川河流域发展经济林的几点意见

本文提出的发展三川河流域经济林、提高综合治理经济效益的意见主要是:引进优良果树树种与品种,推广果园覆膜、覆草保水技术,施行果园间作绿肥和根外追肥技术,改造小老树和合理密植等。作者根据试验结果与实践经验,对以上问题进行了较为具体的讨论,将对解决这方面的实际问题起到一定的作用。     

Landscape changes influence the reproductive behaviour of a key ‘capital breeder’ snake (Boa constrictor occidentalis) in the Gran Chaco region, Argentina

Many wild reptile species are threatened by habitat loss. However, the way in which changes in landscape patterns influence intraspecific ecological processes is not completely understood. Boa constrictor occidentalis is an endangered species and has a special conservation value since it is endemic of dry forests in the Gran Chaco region. Because the Gran Chaco is largely threatened due to habitat loss it is necessary to know how landscape changes influence this species. Therefore, we evaluated the effects of forest loss and landscape composition on the reproductive life-history parameters. Landscape changes were assessed by analyzing satellite imagery and reproductive parameters were determined by ultrasound images of the reproductive structures. The obtained results indicate that habitat loss may affect body condition, clutch size and testicular volume of the Argentine boa constrictor. We also found that the spatial pattern of vegetation influences the distribution of females and males in the landscape. Matting aggregations are scarce in shrublands. Therefore, our study shows that forest loss could enhance vulnerability to extirpation through constraints placed on reproduction. We encourage resource managers to evaluate sensitive reproductive life-history parameters as well as habitat deterioration to asses the conservation status of the populations of the Argentine boa constrictor. Since the Gran Chaco forest, a key habitat to the species’ reproduction, is largely threatened, strong conservation action is needed to halt and reverse forest loss in this region.