土地利用方式对土壤动物多样性的影响

为了解不同利用方式下土壤动物多样性状况及其演变,对广州市东部郊区的水稻田、蔬菜地、果园旱地和林地4种土地利用类型0～5、5～10、10～15、15～20cm土层进行了土壤动物取样调查,共获得土壤动物24683只,分别隶属于4门10纲23类。统计分析结果表明,土壤动物多样性受土地利用方式的影响明显。果园旱地和林地的个体数显著高于蔬菜地和水稻田,但果园旱地与林地、蔬菜地与水稻田之间无显著差异;果园旱地和林地的土壤动物类群数显著高于水稻田,但果园旱地与林地、林地与蔬菜地、蔬菜地与水稻田之间的差异不显著;林地和果园旱地的复杂性指数显著高于蔬菜地,但林地与果园旱地和水稻田、水稻田与蔬菜地之间的差异不显著（P〈O．05）。土壤动物的个体数和类群数量随着土壤深度的增加而明显减少,但不同土地利用方式下各层土壤动物的丰富度及其随土层加深而递减的程度则有明显不同,其中,林地和果园旱地的土壤动物在不同土层中较丰富,垂直变化比较和缓,水稻田和蔬菜地的类群数和个体数则随土层的加深而急剧减少。     

不同利用方式下吴江市耕地土壤环境质量变化

土地利用方式的不同影响着土壤环境质量的变化。文章采用了2003年江苏省吴江市耕地质量监测中资料,分析了6种不同土地利用方式下的土壤养分及Pb、Cr、Hg、As、Cd等5种重金属元素全量的变化,并采用土壤质量综合指数(SQI)法计算不同利用下的土壤环境质量指数。结果表明:近20多年来,吴江市土地利用方式发生了明显的变化,这种变化对本土壤养分和重金属含量产生了十分明显的影响。在稻田、林地、桑园、菜地、果园、旱地六种吴江常见的土地利用方式中,稻田土壤环境质量综合指数显著高于其他利用下,而其他五种利用方式下土壤质量的差别不明显。可见稻田不仅是一种太湖地区传统的利用方式,更是保持环境质量相对最佳的土地利用方式。     

不同利用方式下黄壤旱坡地磷素状况及环境影响分析

通过对贵州黄壤进行采样以及采用无界径流小区法收集地表径流,探索不同利用方式下黄壤旱坡地磷素水平及其地表径流磷浓度的差异。结果表明,不同利用方式下黄壤旱坡地中全磷和有效磷(Olsen-P)含量的大小顺序为连作烟地>烤烟-玉米轮作地>连作玉米地>林地;CaCl_2浸提磷(土壤易解吸磷)和Na0H浸提磷(藻类可利用的土壤总磷)与土壤全磷和有效磷有显著的相关性;土壤富磷化的同时,其磷素的流失风险明显地提高。连作烟地地表径流总磷(TP)和磷酸根态磷(Ortho-P)浓度明显大于连作玉米地.而林地地表径流TP浓度明显小于旱地;黄壤旱坡地地表径流中TP和Ortho-P与土壤有效磷之间存在极显著的相关性(r为0.957、0.875),因而连作烟地磷素的环境影响潜能明显高于其它旱地以及林地。     

典型喀斯特区侵蚀性降雨特征及坡面生物措施水土流失防控效应

降雨类型和生物措施是坡面水土流失的重要影响因素。为研究喀斯特区降雨类型和不同坡面生物措施共同作用下的水土保持效益,以贵州蚂蟥田小流域水土保持监测站2014—2018年5年的径流小区实测数据为基础,分析了112场次的侵蚀性降雨特征,并以降雨量、降雨历时、平均降雨强度为指标对其进行分类。同时,分析了不同侵蚀性降雨类型下6个生物措施径流小区的产流产沙量,生物措施包括自然恢复草地、水土保持林(水保林)和经济果木林(经果林)。结果表明,侵蚀性降雨可以分为3类,通过分析降雨侵蚀力和各生物措施坡面的产流产沙能力,得出降雨的侵蚀能力表现为B雨型(中历时、大雨量、中雨强)>C雨型(短历时、小雨量、大雨强)>A雨型(长历时、中雨量、小雨强),B和C雨型的产沙量占全年总产沙量的85%以上。侵蚀性降雨集中发生在5—10月,占全年总产沙量的92.6%和总产流量的93.2%;3种生物措施的产流产沙量大小为:自然恢复草地>水保林>经果林,水保林和经果林的侵蚀产流量差异不显著(P<0.05)。对比自然恢复草地,水保林和经果林均能够减少侵蚀达50%以上。此外,其削减能力与降雨类型有关,在不同雨型下两种林地的减沙能力为:A雨型>C雨型>B雨型。研究结果可为喀斯特地区以生物措施治理坡面水土流失提供参考。     

LUCC及气候变化对龙川江流域径流的影响

土地利用与土地覆被变化(Land Use and Land Cover Change,LUCC)及气候变化对流域的径流变化影响巨大。为揭示龙川江流域LUCC和气候变化对径流变化的影响,基于SWAT模型,通过设置不同情景,定量分析了不同土地利用类型和气候要素对流域内径流的影响,并结合RCP4.5、RCP8.5两种气候情景对流域未来径流的变化进行了预估。结果显示,(1)SWAT模型在龙川江流域径流模拟中具有较好的适用性,可用SWAT模型进行流域的径流模拟,率定期的模型参数R~2、Ens分别达到0.73、0.71,验证期的模型参数R~2、Ens分别达到0.75、0.74。(2)从土地利用方面考虑,将农业用地转化为林地或草地,均会导致流域径流量的减少,而将林地转化为草地则会引起流域径流量的增加,农业用地、林地、草地三者对径流增加的贡献大小顺序为农业用地?草地?林地。从气候变化方面考虑,流域径流量与降雨量呈正比,与蒸发量呈反比。(3)2006-2015年间龙川江流域LUCC引起的月均径流增加幅度小于气候变化引起的月均径流减少幅度,龙川江径流的变化由气候变化主导,月均径流量总体上减少1.59 m~3·s~(-1)。(4)预估结果显示,RCP4.5和RCP8.5气候情景下,2021-2050年间龙川江流域径流减少趋势明显,分别为1971-2015年减速的2.65倍、3.43倍。     

广州流溪河流域典型农业集水区降雨径流污染物输出特征分析

选取广州市流溪河流域典型农业集水区--新田小流域为研究对象,对研究区降雨地表径流进行定点监测,探讨降雨-径流条件下农业非点源污染物的动态变化规律和不同利用类型的地表景观对非点源污染的贡献情况.结果表明:在降雨事件下,污染物输出浓度总体上高于日常非降雨条件的污染物浓度,T-N、T-P和CODCr的平均输出浓度分别是非降雨条件下的3.8倍、7.8倍和32.1倍;整个降雨-径流过程中,降雨初期是非点源污染物流失的高峰期,污染物浓度变化总体趋势滞后于降雨强度的变化,但与径流量变化趋势总体上相似;从不同地表景观径流产污来看,经生活区的径流CODCr输出浓度显著上升,水田田面径流是引起水体环境N、P污染的主要原因.     

黄土丘陵沟壑区不同土地利用类型对坡地产流、产沙的影响

于甘肃省安家沟流域选择设计15个径流小区,通过对径流小区1986-1999年的水文监测资料进行年尺度上的方差分析、多重比较和相关分析,研究不同土地利用类型对坡地产流、产沙的影响,同时分析年降雨量与坡地单位面积年产流、产沙量的相关关系.结果表明,相同坡度等级下5种土地利用类型坡地的单位面积年产流量之间及单位面积年产沙量之间都存在显著差异,大小顺序均表现为:坡耕地>人工草地>乔木林地>自然草地>灌木林地;在研究的坡度(10°～20°)范围内,同一土地利用类型、不同坡度径流小区的单位面积年产流量差异不显著,坡耕地和人工草地的单位面积年产沙量差异显著;年降雨量分别与坡地单位面积年产流量、产沙量无显著相关性.     

城市小集水区降雨径流污染来源解析

利用深圳市王家庄集水区的降雨径流水质监测数据,运用正定矩阵因子分解法（PMF）定量解析了单个城市小集水区降雨径流污染的主要来源。结果表明：研究区降雨径流的主要污染源为城市污水、管内沉积物和地表径流。其中城市污水以输出氨氮（NH3-N）和总氮（TN）为主,管内沉积物是化学需氧量（CODCr）、总磷（TP）和生化需氧量（BOD5）的主要来源,地表径流为固体悬浮物（SS）的主要来源。PMF模型可作为土地利用方式均一的单个城市小集水区降雨径流污染源解析的有效方法之一,主要污染源的廓线能否保持相对稳定是该模型在降雨径流污染源解析时的主要约束条件。     

岷江流域不同土地利用方式下紫色土有机碳储量特征

以岷江中下游流域紫色土为研究对象,按流域分上中下游区段3个抽样层采样,研究不同土地利用方式下紫色土有机碳储量特征,为紫色土退化评估及地力维护提供参考.结果显示,紫色土有机碳总量以林地(14.151g/kg)显著高于果园地(9.458g/kg)、菜园地(8.542g/kg)、草坡地(7.875g/kg),以玉米地(6.226g/kg)最低.水溶性有机碳含量呈现林地>果园地>菜园地>草坡地>玉米地趋势.同时,流域上、中、下游紫色土有机碳总量总体上差异显著,且以上游区段紫色土有机碳总量最高.流域中下游紫色土有机碳总量变化较大,其中,林地以下游高于中游,果园及草坡地以中游高于下游.菜园地、玉米地在3个区段上差异未达显著水平.岷江流域紫色土有机碳储量总体特征表现上游最高,中下游变化复杂,下游略高于中游区域.图1表4参10     

巢湖典型低山丘陵区不同土地利用类型壤中流养分流失特征

以巢湖典型低丘山区坡地的6种主要土地利用类型（弃耕地、尾矿裸地、灌木林地、荒草地、马尾松林地和人工恢复林地）为研究对象,通过定位观测与收集坡面壤中流,探讨该地区壤中流养分流失动态变化特征。结果表明,巢湖低丘山区典型土地利用类型壤中流发生概率为灌木林地和荒草地较高,尾矿裸地最低（仅在0～20cm土层产生）;表层壤中流氮含量为尾矿裸地最高,人工恢复林地最低,壤中流磷含量为弃耕地最高,尾矿裸地最低;壤中流氮素流失以溶解态NO3-N为主,并随雨季的到来而呈下降趋势,随土层加深呈先下降后升高趋势;磷主要以有机溶解态形式流失,随土层加深而呈下降趋势。相关分析表明,地表总盖度、地表植被均匀度、土壤养分含量与壤中流氮、磷含量间存在显著相关性,而降雨特征（降雨量、降雨强度）与壤中流氮、磷含量问相关性不显著。由于人为开采严重,在分析该地区壤中流氮素含量时,应注意干湿沉降的影响。     

Representation of the world's biophysical conditions by the global protected area network

Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.     

Quantitative composition of the defensive secretion ofBledius species (Coleoptera: Staphylinidae: Oxytelinae) is adapted to naturally occurring predators

Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.     

Democracy versus development: New urban debates

The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.     

Achieving Open Access to Conservation Science

Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación     

A framework to measure the wildness of managed large vertebrate populations

As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.     

Sexual Predators,Energy Development,and Conservation in Greater Yellowstone

Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.     

Comparison of the insecticidal effects of water extracted and intact aromatic plants onAcanthoscelides obtectus,a bruchid beetle pest of kidney beans

Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

Some polyphagous Homoptera gain protection from their natural enemies by feeding on the toxic plantsSpartium junceum andErythrina corallodendrum (Leguminosae)

Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.