Is landscape context important for riparian conservation? Birds in grassy woodland

An important challenge for riparian management is to determine the extent to which landscape context influences the faunal assemblages of riparian habitats. We examined this challenge in the variegated landscapes of southeastern Queensland, Australia where riparian vegetation is surrounded by both extensive grazing and intensive cropping. We investigated whether riparian habitats adjacent to different landuses support similar bird assemblages. Three types of riparian habitat condition were sampled (uncleared ungrazed; uncleared grazed; cleared grazed) in four different land-use contexts (ungrazed woodland; grazed woodland; native pasture; crop) although only six of the 12 possible treatment combinations were available. Eighty percent of bird species responded significantly to changes in both riparian habitat condition and landscape context, while fewer than 50% of species were significantly influenced by landscape context alone. The influence of landscape context on the bird assemblage increased as the surrounding land use became more intensive (e.g., woodland to native pasture to crop). Riparian zones have been shown to have consistently high biodiversity values relative to their extent. These findings suggest it is not enough to conserve riparian habitats alone, conservation and restoration plans must also take into consideration landscape context, particularly when that context is intensively used land.     

基于GPS与无人机遥感反演草地生物量的放牧场利用强度评估

天然草地是放牧畜牧业生产赖以生存的物质基础。为了评估天然草地利用情况,该文通过GPS获取牧群采食轨迹数据来估算采食强度,利用无人机遥感估算模型反演草地生物量的时空分布,将畜群采食强度与天然草地生物量进行融合,探索不同区域畜群的采食强度与草地生物量;分别将采食强度与生物量分类进行对比,根据两者的取值情况,获得各区域草地的利用情况,采食强度与天然草地生物量分类满足以下关系可得草地利用情况:若两者等级相等,则草地利用适中;若前者等级大于后者,则草地过度利用;若前者等级小于后者,则草地轻度利用。以新疆生产建设兵团第八师一五一团紫泥泉牧场为例,对研究区进行监测评估。结果表明,研究区中区域3被合理利用的草地面积最大,为612 m2,其他区域草地被不合理利用的面积占所在区域面积的50%以上。该方法对合理利用草地,实行划区轮牧,促进畜牧业健康发展具有重要意义。     

Longitudinal patterns in bird reporting rates in a threatened ecosystem: Is change regionally consistent?

Work in many parts of the world has discussed the decline of biodiversity in regions dominated by agriculture. We report the results of a major study documenting the longitudinal profiles of birds between 1998 and 2009 within 66 patches of temperate woodland in a heavily cleared and grazed agricultural region of south-eastern Australia. Many researchers have forecast the loss of bird biota from this region and others that also were formerly dominated by temperate woodland.We had sufficient high quality data to analyse the longitudinal profiles of reporting rates for 76 of the 116 individual bird species recorded in our 12-year study. Unexpectedly, only four of the 76 species analysed (5.6%) exhibited a significant negative linear decrease in reporting rate. More surprisingly, 32 (42.1%) exhibited a significant positive linear increase in reporting rate, including several taxa of conservation concern. These increases occurred despite a series of below-average rainfall years. Reporting rates were too low to formally model long-term trends in some other bird species widely considered to be of conservation concern such as the Diamond Firetail (Stagonopleura guttata) and Speckled Warbler (Chthonicola sagittata).Many authors have used functional (and other) groups to forecast bird species likely to be lost from Australia’s temperate woodlands. However, we found no clear links between life history attributes and long-term trend patterns of species.Our findings contrast with recent findings from other temperate woodland-dominated regions in eastern Australia where losses in bird populations have been documented. However, they parallel other investigations such as in central New South Wales. These similarities among, and differences between, studies suggest regional differences in temporal patterns in bird population dynamics. Many of the observed changes in reporting rates were positive and they provide hope that forecast future losses of a large proportion of existing temperate woodland bird assemblages in south-eastern Australia may not be realised uniformly in all regions.     

黄土丘陵区沟间地与沟谷地面积比例问题探讨

本文利用航空相片沟间地与沟谷地分异明显的特点,在陕北黄土丘陵区按地表形态,选出典型地段的样片,勾绘谷缘线,量算沟间地与沟谷地的面积。得出:1.陕北黄土丘陵区沟间地与沟谷地的面积比例关系有区域性差异,但不存在地带性规律;2.二者的面积比例既受古地形制约,也受人类开垦历史的影响;3.有深层滑坡的地域,沟间地比例小,在35%左右;4.河源区沟间地比例大,在45%左右;5.其余大部分地区沟间地比例均在40%左右。     

GIS支持下1985～2000年北京林地数量、质量演变与驱动分析

在收集、研究1985年、1995年、2000年北京土地覆盖类型的图像和矢量数据的基础上,提取了不同时间段北京林地相关的数据信息,并从多个角度分析了研究区内各类林地与其它土地覆盖类型之间相互转化和各类林地之间的演替情况,得出2000年北京各类林地面积总量与1985年相比有少量增加,但林地总体质量水平却有下降趋势;并从经济社会发展以及国家及北京的生态环保政策等方面对林地演变的驱动因子进行了分析。     

半干旱丘陵地区林地在荒漠化中作用及其成因分析研究——以内蒙古四子王旗南部为例

干旱、半干旱区的林地在保护国土、改善生态环境、维护生态平衡、拓宽人类活动空间、优化生存环境质量等方面起到了重要作用;尤其是在生态失衡,环境遭到破坏的荒漠化发生地区,以某种特殊目的营建起的农防林、水土保持林、水源涵养林等既是农牧业的人工防护屏障,又是整个农业生态系统的骨架;但是同时也讨论由于过度放牧、樵采和垦荒等破坏植被后导致的沙化,使林地成为沙源地的特殊情况。     

Nature,extent and severity of soil erosion in upland Scotland

This paper examines the nature, extent and severity of soil erosion in upland Scotland, an area subject to land management pressures typical of temperate maritime uplands. Erosion features were classified and their area measured from aerial photographs. Some 12 per cent of the upland area sampled was subject to some form of erosion, which is very similar to the percentage for Europe as a whole. The most significant erosion category was peat erosion, with 6 per cent of the area being affected; a figure which increased to 20 per cent in one sub-region. Peat erosion varied in severity, with the most severe erosion being in areas of eastern Scotland with the greatest land management pressures. Gully erosion of slopes on mineral soils was found in almost 5 per cent of the area sampled, particularly in sub-regions with large amplitude of relief. Debris flow/cone features and screes were less extensive and largely found at higher altitudes. Footpath erosion was mapped in popular mountain areas, but overall the mean length of eroded footpaths was less than that of large gullies. There was little evidence of spatial linkages between erosion of mineral soils and land management at the scale of the survey. Separating the roles of upland management and extreme rainfall events in the inception of erosion remains a key issue in the study of accelerated erosion in temperate maritime upland areas. Some guidance for management is presented.     

无人机遥感影像面向对象分类方法估算市域水稻面积

针对如何高效地从无人机遥感影像中提取农作物样方数据,用于农作物面积遥感估算,该文以浙江省平湖市为例,利用面向对象分类方法对无人机影像进行水稻自动化识别,作为样方数据与卫星遥感全覆盖空间分布分类结果结合,采用分层联合比估计进行2014年单季晚稻面积估算。然后,与人工目视解译识别方法获取的水稻样方数据推断的区域水稻面积估算的结果进行精度、效率对比分析。研究结果表明:1)利用面向对象分类方法对无人机影像进行分类,总体分类精度达到93%以上,满足构建样本的要求;2)通过区域作物估算对比分析发现,面向对象分类方法对无人机影像进行水稻识别,构建平湖市单季晚稻的样方数据,能够替代人工目视解译样方准确推断区域作物种植面积,有效地提高了无人机影像在遥感面积估算中的应用效率。     

Short and medium-term evolution of a coastal sector in Cadiz,SW Spain

The present paper is a combined study on the medium and short-term evolution of the littoral between Chipiona and Rota (SW Spain). The analysis of coastal evolution over a period of 24 years (i.e. medium-term), was carried out using six, well temporally spaced, photogrammetric flights. Cliff top and dune toe were used as shoreline indicators to solve problems related to the use of watermark in tidal environments. Short-term littoral variations were monitored monthly by means of an electronic theodolite over a period of 2 years. The width variations of the dry beach were surveyed by always using a constant, average value for the mean sea level position derived from the numerous surveys carried out. The obtained data was representative of both seasonal and annual variations.     

GIS支持下1985-2000年北京林地数量、质量演变与驱动分析

在收集、研究1985年、1995年、2000年北京土地覆盖类型的图像和矢量数据的基础上,提取不同时间段北京林地相关的数据信息,并从多个角度分析研究区内各类林地与其它土地覆盖类型之问相互转化和各类林地之间的演替情况,得出2000年北京各类林地面积总量与1985年相比有少量增加,但林地总体质量水平却有下降趋势;并从经济社会发展以及国家及北京的生态环保政策等方面,对林地演变的驱动因子进行分析.     

丘陵山区林地土壤养分状况研究——以江西省兴国县为例

在江西省兴国县林地采集84个耕层样品,样地按坡向、海拔、土壤类型和林分类型分类,用来比较和确定对林地土壤肥力的影响。分析结果表明:该区林地土壤pH、全N、有机质、全P和速效P的含量均较低,坡向朝南的低海拔土壤比坡向朝北的高海拔土壤的全N和有机质含量低;全N、有机质、全P含量在马尾松纯林中最低,全K含量却最高;全N和有机质含量在阔叶林中最高;全N和有机质含量由黄壤、黄红壤、棕红壤到红壤依次降低;坡向和全N、有机质含量呈显著正相关关系,海拔和全N、有机质含量呈极显著正相关关系;海拔和全P的相关关系达显著水平,呈显著正相关关系。