河岸植被缓冲带生态水文功能研究进展

河岸植被缓冲带是河岸生态系统的重要组成部分,对河岸生态系统的生态及水文过程具有重要的影响。世界上许多国家已将河岸植被缓冲带列为河岸生态系统管理的一个重要内容,并在一些国家被作为控制农业流域非点源污染的最佳管理措施。河岸植被缓冲带的生态水文功能体现在控制河岸侵蚀、截留地表径流泥沙和养分、保护河溪水质、调节水温、为水陆动植物提供生境、维护河溪生物多样性和生态系统完整性以及提高河岸景观质量等多个方面。本文综述河岸植被缓冲带生态水文功能方面的研究进展,总结了一些研究中提出的不同河岸植被缓冲带功能发挥所需要的宽度,同时指出由于河岸生态系统保护的目标,侧重的功能,研究区域土壤、地形、植被、排水特征等因素各异,河岸植被缓冲带生态水文功能发挥所要求的实际宽度也有所不同。     

黄河中下游河岸缓冲带土壤粒径分形特征

在人类活动与自然因素的共同作用下,黄河中下游河岸缓冲带土壤结构和植被等受到不同程度的破坏.本研究选择黄河中下游郑州一开封段河岸缓冲带作为研究区,探讨河岸人工林表层0～20 em土壤颗粒组成和分形维数在不同植被类型和河岸缓冲距离的分布特征及其与群落特征的关系.结果表明:1)研究区土壤颗粒质量分数呈非均匀分布,土壤质地空间分布表现为同质性,不同植被类型和河岸缓冲距离对土壤颗粒组成与土壤颗粒分形维数D值的影响差异不显著,D为2.75左右,土壤结构良好;2)D值与黏粒质量分数均与土壤全碳(TC)、总有机碳(TOC)和全氮(TN)的质量分数显著正相关(P＜0.01),砂粒质量分数则与TC、TOC和TN质量分数呈显著的负相关(P＜0.01),粉粒质量分数只与TN质量分数在0.05水平显著正相关;3)草本高度、乔木胸径、高度和郁闭度与D值、粉粒和黏粒质量分数呈正相关,与砂粒质量分数呈负相关.说明河岸人工林覆盖和生物量越大,土壤结构越好.     

沈阳地区河岸植被缓冲带对氮、磷的削减效果研究

为充分了解河岸植被缓冲带对地表径流污染物的去除效果, 本研究选取辽宁省沈阳市两条典型河流——浑河与蒲河为对象, 研究其滨水不同河岸植被缓冲带对地表径流氮、磷污染物的削减效果。结果表明: 在6 种河岸植被带中, 人工林草地对氮的削减效果最好, 对总氮、硝态氮和铵态氮的平均削减率分别为47%、36%和31%; 人工林地对磷的削减效果较好, 平均削减率为74%; 而人工林地对氮以及人工草地对磷的削减效果较差。随长度增加, 河岸植被缓冲带对地表径流污染物的削减效果基本呈增强趋势。以上研究结果说明不同河岸植被缓冲带对地表径流中氮、磷的削减各有优点。在对遭受污染的河流进行生态修复时, 应考虑环境污染特点和地表特征, 以充分发挥河岸植被缓冲带对污染物的削减优势。     

华北土石山区草本植被覆盖度对降雨溅蚀的影响北大核心CSCD

通过野外人工模拟降雨试验,研究植被覆盖度对雨滴动能和土壤溅蚀量的影响。结果表明:(1)在相同植被覆盖度条件下,溅蚀量随雨强的增大而增大。植被覆盖度与植被拦截后雨滴的动能呈负指数函数关系;(2)相同降雨强度条件下,溅蚀量与植被覆盖度呈负相关,这一关系可用以e为底的指数函数来表示。溅蚀量随植被覆盖度的增大而减小,在植被覆盖度为40%前十分显著,可认为植被覆盖度40%是一个临界值;(3)在同一雨强相同植被覆盖度的情况下,溅蚀量随溅蚀距离的增大而减少,各溅蚀距离内的溅蚀量与植被覆盖度呈负相关。植被覆盖对溅蚀的影响随距离的增加而逐渐减弱。     

城市扩张对农田景观中非农生境的影响*——以辽宁省沈阳市沈北新区为例

农田景观因其巨大面积和更高的生产力,在全球生物多样性维持,甚至濒危物种的维持中扮演着重要角色。而农田景观中非农生境被蚕食的现象较为突出,尤其城市周边农田景观中更为普遍。本文以沈阳市沈北新区为例,采用景观紊乱度法将其划分为城市、城市边缘区和乡村3个区域,利用GIS技术分析3个区域农田景观中非农生境类型、数量与面积比例,探讨城市扩张对农田景观中非农生境影响程度。结果表明,随着与城市中心距离的增加,由城市、城市边缘区至乡村,非农生境类型呈现逐渐增加趋势,靠近城市中心的非农生境仅有林地,而在乡村区域有草地、林地、水域和农村道路4种类型。非农生境斑块数量比例呈现总体增加趋势,城市平均比例为8.63%、城市边缘区平均比例为17.08%、乡村平均比例为22.48%。非农生境面积比例呈现先增后减的倒"U"字型变化,城市边缘区的非农生境面积比例最高,值为1.93%。非农生境斑块密度呈现先增加、再减少和后增加的变化趋势,城市边缘区的非农生境斑块密度最小。最大斑块指数和聚集度指数呈现先减少后再增加的趋势,城市边缘区的非农生境最大斑块指数和聚集度指数最小。景观形状指数和多样性指数呈现先增加后减少的趋势,城市边缘区景观形状指数和多样性指数最大。总体而言,距离城市中心最近的城市区域受城市化强烈影响后,保留在城市景观之中的农田景观重新建立一种相对稳定的景观格局,残留其间的非农生境类型单一、斑块数量低,斑块较大、形状规则;正在受到城市建设切割的城市边缘区农田景观中非农生境面积比例、景观形状指数和多样性指数表现为虚高,但其斑块密度、最大斑块指数和聚集度指数均较小;距离城市中心最远的乡村区域非农生境受城市化影响较弱,类型趋于多样、斑块数量比例高、景观异质性较高。     

基于像元二分法的沙地植被景观格局特征变化分析

景观格局与过程的关系研究是目前景观生态学的主要目标和研究热点,而沙漠化是一种典型的景观演化过程。基于景观生态学原理,运用遥感与地理信息系统技术,以古尔班通古特沙漠南缘为研究区,选择近40 a(1977-2010年)间不同年降水量梯度的代表年份(1977年、1990年、2001年和2010年),利用Landsat MSS/TM/ETM+遥感数据对沙地植被景观格局变化进行了分析。结果表明:1977-2010年间,古尔班通古特沙漠南缘沙地植被呈现恢复—退化—恢复交替变化趋势,总体处于恢复趋势中;景观水平上沙地植被破碎化程度处于增加趋势,景观异质性增强,斑块形状趋于复杂;类型水平上不同盖度沙地植被破碎化程度呈不同趋势波动,总体呈盖度相对高的植被破碎化程度增加,而盖度相对低的植被破碎化程度降低的趋势。1977-2010年间,沙地植被斑块重心在西南-东北方向交替呈现,重心轨迹形成"Z"形。总体来看,植被斑块由沙漠西南缘向沙漠腹地东北方向扩张。年降水量波动与沙地植被盖度演化方向、景观破碎化程度、不同盖度沙地植被比例、不同盖度沙地植被破碎化程度、不同盖度沙地植被斑块重心迁移方向均具有密切关系,即干旱区沙地植被景观格局演化特征与年降水波动具有很强的关联性。     

翠屏区植被覆盖及其景观格局变化遥感分析

植被覆盖变化对区域生态环境质量有着重要的影响.分析翠屏区近年来植被覆盖变化趋势,可为该区域植被覆盖动态变化提供监测方法.利用Landsat数据以及相关辅助数据,通过最大值合成的NDVI的变化趋势和像元二分模型,分析翠屏区2001-2009年植被覆盖变化.结果表明:近9 a来翠屏区植被整体覆盖变化改善与退化同时存在,但改善面积大于退化面积;高覆盖度植被面积明显增加,整体植被面积呈增加趋势.此外,选用7个景观指数分析了2001年与2009年不同植被盖度的景观格局变化,发现2009年高盖度植被斑块密度比2001年低,但其整个区域破碎度比2001年高.2009年斑块周长面积分维数和Shannon's多样性指数比2001年小,但2009年高盖度植被最大斑块面积和聚合度都较大,其具有的生态自然保护功能明显强于2001年.因此,应继续加强和完善植被覆盖保护措施,以维护植被高覆盖的良好趋势.     

空间粒度变化及土地利用分类对景观指数的影响——以山西省闻喜县为例

以山西省闻喜县为例,利用该县1:10000土地利用现状图作为数据源,应用GIS技术以及景观格局软件Fragstats,研究了土地利用类型数不同时景观格局指数的空间粒度效应和不同粒度下土地利用类型数对景观指数的影响。结果表明:随粒度增加,斑块密度、景观形状指数、景观聚集度呈逐渐下降趋势,且下降幅度逐渐减小,周长面积比分维数总体呈上升趋势,最大斑块指数和Shannon多样性指数无明显变化。随土地利用类型数目的增多,斑块密度、景观形状指数、Shannon多样性指数呈阶梯式上升趋势,最大斑块指数呈阶梯式下降趋势,周长面积比分维数无明显变化,景观聚集度的变化曲线比较复杂。     

泾河流域植被景观格局对流域径流的调节作用

对黄土高原腹地泾河流域12个子流域植被景观格局和流域径流动态的关系进行了探讨。结果表明景观层次上植被的整体空间格局对流域径流动态有着如下调节作用:(1)泾河流域4种植被景观类型中,森林灌丛植被景观流域年径流量最大,径流年内分配比较均匀,但年际变化很大;其次为复合植被景观,农业植被景观流域径流量较小,且主要集中在汛期;草地植被景观流域径流极小,主要发生在汛期的7~8月份,年际变化比较小。(2)在主要植被景观指数中,景观破碎度、景观多样性与流域径流正相关,景观聚集度、景观优势度与流域径流负相关,景观形状与流域径流相关不显著。(3)结构复杂的植被景观对流域径流具有较好的调洪补枯作用。随着景观破碎度和景观多样性的增大,流域径流年内分配趋于均衡;而随景观聚集度的增大,流域径流年内分配则趋向集中,景观形状对流域径流调节作用不明显。(4)多样性高的植被景观可降低极端径流出现,维持流域生态系统的稳定性。     

嘉陵江流域3大水系的植被景观异质性差异

利用景观指数从景观空间组分、空间构型以及空间梯度变化3方面比较和分析了嘉陵江流域内3大水系的植被景观异质性差异。结果表明：（1）涪江水系和嘉陵江干流以栽培植被和针叶林为优势,渠江水系则以栽培植被和阔叶林为主。针叶林和草甸在涪江水系中的破碎化程度较高。而嘉陵江干流和渠江水系中针叶林和灌丛的破碎化程度较高。（2）嘉陵江干流水系在植被景观总体上破碎化程度高、斑块聚合性弱。景观多样性高。而渠江水系则表现为景观破碎化较高,斑块聚合性强,景观多样性低的分布特点。除景观破碎化程度最低外,涪江水系在其它方面均处于前两者之间。（3）沿着河流汇聚方向,3水系在异质性方面均表现出斑块数量减少、斑块间距缩小、聚合性增强、植被景观破碎化和多样性明显降低的总趋势。     

延河流域植被景观格局与水文连通性关系

为探究延河流域植被景观格局对水文连通性的影响,基于土地利用分类成果和水文连通指数空间分布,探讨了延河流域植被景观和水文连通性的格局特征,并借助Geoda软件平台基于空间自相关理论探究了林草植被景观格局与水文连通在空间上的相关性。结果表明:(1)延河流域草原带、森林草原带和森林带中林草景观与水文连通性都呈现空间自相关性。3个地带中林地景观的平均斑块面积、聚合度指数和斑块面积百分比都与水文连通性呈现显著的统计学上的正相关性以及空间正相关性; 景观分离度和斑块破碎化指数与水文连通性呈显著的统计学上的负相关性以及空间负相关性。(2)林地景观的优势度和聚集程度的增加并不能带来水文连通性的降低,而其斑块破碎化的增加会带来水文连通性的降低。对于3个地带的草地景观,其表现则与林地完全相反,增加草地景观的面积,提高草地植被的优势度,使草地斑块连续集中可以促使水文连通性降低。(3)在探究水文连通性和植被景观格局相关关系的空间回归模型中,空间滞后模型和空间误差模型拟合效果远好于普通线性回归模型,综合来看,空间滞后模型对植被景观格局与水文连通性的空间关系的解释能力更强。研究结果可为延河流域植被景观格局的设计和规划,提供有效的参考。     

Thresholds in landscape parameters: occurrence of the white-browed treecreeper Climacteris affinis in Victoria, Australia

The concept of critical thresholds of habitat loss has recently received considerable attention in conservation biology and landscape ecology, yet empirical examples of thresholds are scarce. Threatened species management could benefit from recognition of thresholds because conditions under which populations are at risk can be specified. In this study, 56 woodland patches in north-west Victoria were surveyed for the white-browed treecreeper Climacteris affinis, a threatened insectivorous bird of the semi-arid zone of southern Australia. Comparisons with historic records indicate the species’ range is contracting in Victoria. Using logistic regression and hierarchical partitioning, two models of patch occupancy were developed. Tree species composition was an important factor in both models, confirming the treecreepers’ affinity for belah Casuarina pauper and slender cypress-pine Callitris gracilis-buloke Allocasuarina luehmannii woodlands in north-west Victoria. The first model emphasized the importance of demographic isolation: probability of patch occupancy decreased with distance to the nearest occupied patch. A threshold response in demographic isolation was apparent. In agricultural landscapes, most suitable woodland patches within 3 km of an occupied patch were occupied, whereas patches beyond the threshold were vacant. The threshold distance increased to a minimum of 8 km in a matrix of native vegetation, suggesting landscape context affects the response of white-browed treecreepers to habitat fragmentation. Demographic isolation is a quasi-dependent variable and therefore a second model was developed using surrogate variables for demographic isolation. A positive relationship with the proportion of woodland cover in the landscape (100 km²) emerged as the pre-eminent explanatory factor. Depending on woodland quality, a threshold of patch occupancy was apparent at levels of woodland cover between 15 and 25%. However, belah and slender cypress-pine-buloke woodlands now cover only 10% of their original extent in the region. These results highlight the inter-dependence of patch isolation with the amount and quality of habitat in the landscape and the implications this has for maintaining functional connectivity. The retention (or restoration) of suitable habitat is the critical issue for conservation of the white-browed treecreeper, but in landscapes below the threshold of habitat cover, viability of local populations may be influenced by the configuration and quality of remaining habitat.     

黄土丘陵小流域景观空间格局动态分析——以固原市上黄试区为例

 为黄土高原土地资源合理利用及区域可持续发展提供参考,以上黄试区为例,在地理信息系统支持下获得计算景观多样性的有关参数,选取斑块大小及数量、分维数、斑块伸长指数、多样性、优势度、均匀度和破碎度等指标,对黄土丘陵小流域10年来景观多样性动态变化进行分析。结果显示:1995—2004年,该试区总斑块数增加了6个,斑块变化明显的主要表现为:坡耕地及天然草地斑块分别减少19个和12个,人工草地斑块及梯田分别增加15个和9个;平均斑块面积及平均斑块周长分别下降了0.14hm2和185.36m2;梯田、天然草地、疏林地、园地及居民点用地分维数,都有不同程度的下降,而坡耕地、人工草地、灌木林地及未利用地景观的分维数有所上升,水浇地、川台地、乔木林地、水域景观分维数保持不变;上黄试区景观异质性特征表现为:均匀度指数下降5.86,景观破碎度指数上升0.002,人为干扰度增加1.95,景观类型多样性指数下降0.25,优势度指数上升0.25。目前,试区从耕地及草地为主的景观生态系统,转变为以林地和草地景观为主的高度异质化的景观生态系统,人类活动的干预,是驱动该试区景观空间格局变化的主要驱动因素。     

河岸带不同植被类型对土壤有机碳和全氮分布特征的影响-- 以北京地区温榆河为例

河岸带生态系统是河流生态系统和陆地生态系统之间的生态交错带,也是一个敏感和脆弱的生态区域。由于受河道周边人类活动的干扰,河岸带生态系统的植被类型发生了巨大变化。本文以北京市地区的温榆河为研究对象,分析了河岸带7种植被类型对土壤有机碳和全氮含量及其空间分布特征的影响。结果表明:(1)河岸带不同植被类型对土壤有机碳和全氮的影响主要表现在表层土壤,尤其是0~5 cm土层,而对5 cm以下土层的影响相对较小。(2)河岸带不同植被类型土壤全氮和有机碳含量的空间分布特征具有显著差异。随着土层深度增加,土壤全氮和有机碳整体上呈下降趋势,但不同植被类型的垂直变化规律有较大差异,如自然草地、退耕撂荒地和林地的土壤有机碳、全氮含量随土层深度加深而降低的速率明显高于农田生态系统。(3)在0~30 cm土壤剖面上,土壤有机碳平均含量从高到低依次为杨树林(9.54 g.kg 1)、自然荒草地(9.33 g.kg 1)、梨树果园(9.18 g.kg 1)、火炬树林地(8.89 g.kg 1)、退耕撂荒地(7.91 g.kg 1)、玉米地(7.22 g.kg 1)和黄豆地(7.17g.kg 1);土壤全氮的平均含量从高到低依次为自然荒草地(1.30 g.kg 1)、杨树林(0.91 g.kg 1)、梨树果园(0.90g.kg 1)、火炬树林地(0.83 g.kg 1)、退耕撂荒地(0.80 g.kg 1)、玉米地(0.72 g.kg 1)和黄豆地(0.70 g.kg 1)。     

基于CA-Markov模型的土地利用景观格局预测研究

土地利用景观格局分析及预测,对平衡经济发展和生态保护、实现土地可持续生态利用和保护管理具有重要意义。本文以江西省抚州市东乡县为例,利用2005年和2015年两期遥感影像,获取东乡县土地利用类型转化数据,结合景观生态学研究了东乡县近10年的土地利用景观格局变化特征;运用CA-Markov模型对土地利用变化过程进行模拟,预测和分析了东乡县未来10年土地利用景观格局特征。结果表明:东乡县在过去10年建设用地、耕地分别增加了71.82、10.76 km~2,水域、林地和未利用地相应减少,减少幅度顺序为未利用地水域林地;各景观斑块分布均匀,景观多样性增加;景观形状趋于简单,相互之间连通性降低、关系变弱。人类经济活动及土地利用政策对东乡县景观格局有显著影响。到2025年东乡县建设用地将增加68.72 km~2,水域、林地和未利用地仍将不断减少,但耕地有所增加;景观斑块数增加,形状略趋复杂;景观异质程度提高,有向多样化、均匀化发展的变化趋势。总体来说,东乡县景观格局正逐步朝着稳定、均匀和多样的方向发展,但仍需加大力度保护和增加耕地资源,控制和合理规划建设用地,维持生态环境平衡。     

Riparian zones provide for distinct bird assemblages in forest mosaics of south-east Australia

Riparian zones are a characteristic component of many landscapes throughout the world and increasingly are recognised as key areas for biodiversity conservation. Their importance for bird communities has been well recognised in semi-arid environments and in modified landscapes where there is a marked contrast between riparian and adjacent upslope vegetation. The value of riparian zones in largely intact landscapes with continuous vegetation cover is less well understood. In this study, birds were surveyed at 30 pairs of riparian and adjacent non-riparian sites in extensive mesic forests of the Victorian Highlands, Australia. Riparian sites were floristically distinct from non-riparian sites and had a more complex vegetation structure, including a mid-storey tree layer mostly absent from non-riparian sites. Bird assemblages at riparian sites had significantly greater richness, abundance and diversity of species than was recorded at adjacent non-riparian sites. Species composition also differed significantly between these habitat types. Compositional differences in assemblages were due to a suite of distinctive species in each habitat and to significant contrasts in the densities of species that occurred in both habitat types. Many species (36%) attained a significantly greater abundance in riparian habitats. The distinctiveness and richness of the riparian avifauna contribute to the diversity of continuous forest landscapes. The spatial patterning of the avifauna, the occurrence of complementary assemblages, the presence of rare species and the potential for riparian habitats to serve as refuges, all point to the value of riparian zones and highlight the importance of landscape-level planning and management for avifaunal conservation.     

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.     

A river runs through it: Land-use and the composition of vegetation along a riparian corridor in the Cape Floristic Region, South Africa

Riparian zones are important for the many ecosystem services they supply. In settled areas, the vegetation of such zones is shaped by human land-use; this often creates conditions under which alien plant species thrive. Alien plants have been shown to induce large-scale changes in riparian habitats, and they pose a major threat to the continued provision of key ecosystem services. We used direct gradient analysis to assess correlations between land-use and the composition of vegetation along a riparian river corridor in the highly transformed landscape surrounding Stellenbosch in South Africa’s Western Cape Province. Vegetation plots were sampled along the entire length of the river from headwaters to estuary (ca. 40 km). Plant community composition was analyzed in relation to land-use data collected in the field, and additional land-use variables computed from digital land-cover data. Patterns of plant community structure were found to be directly related to land-use, with measures of cover, richness, and diversity differing significantly among land-use types. Portions of the riparian zone adjacent to agricultural land had the greatest level of alien plant cover, while areas bordered by urban land maintained the highest alien species richness. Areas adjacent to grazing and natural lands showed intermediate and low levels of invasion, respectively. Several native species were found to persist in areas with high abundance and diversity of invasive alien plants, suggesting that they will be valuable focal species for future restoration attempts. Due to the level of human-mediated change in many areas of the riparian zone, restoration to historic conditions over most of the river is not considered feasible. These areas should be recognized as examples of novel ecosystems, and management efforts should focus on restoring or creating desirable ecosystem functions, rather than on achieving assemblages comprising only native species.     

The influence of social behaviour, dispersal and landscape fragmentation on population structure in a sedentary bird

White-browed Babblers Pomatostomus superciliosus lived in groups of up to 13 birds in the highly fragmented landscape of the WA wheatbelt. Contacts between these groups and sexual differences in dispersal behaviour interacted with the landscape mosaic at a number of spatial scales to produce a hierarchically structured population with four levels of organization: (1) groups, which were the basic breeding unit; (2) social neighbourhoods, where group interactions were frequent, and male dispersal and female post-natal and breeding dispersal occurred; (3) local population neighbourhoods, which contained social neighbourhoods between which female natal dispersal was frequent; and (4) metapopulations, which contained local population neighbourhoods between which dispersal was infrequent. The boundaries of these structural units, with the exception of the group, were not discrete and were influenced by the structure of the landscape they occupied.Interactions between groups occupying different patches were rare, and the frequency of group interactions was lower in small patches. Male dispersal was restricted to groups within the same patch or in patches less than 1 km apart. Therefore, decreasing patch size and increasing patch isolation resulted in smaller social neighbourhoods. Males generally dispersed to smaller groups and these dispersals may have enhanced the productivity of these groups by increasing their size. Therefore, habitat loss and fragmentation are likely to disrupt social neighbourhoods resulting in lower levels of social interaction and reduced productivity.The size and configuration of local populations were dependent on female natal dispersal, which in turn depended on landscape connectivity. White-browed Babblers used remnant vegetation in preference to other landscape elements when dispersing, but were not dependent solely on corridors. The permeability to dispersal of the boundaries between remnants and agricultural vegetation was dependent on patch configuration. Changes in boundary permeability were found to alter connectivity between habitat patches in a complex and asymmetric manner. Therefore, it is essential to consider landscape connectivity in a spatially explicit context for species that use some elements of the landscape mosaic in preference to others when dispersing.Habitat loss and fragmentation impose a complex set of changes, at a number of different scales, to processes that affect aspects of a species' life history. In order to manage species in fragmented agricultural landscapes it is necessary to understand the hierarchical structure of their populations, and how processes affect the different organizational levels within this structure.