南岳珍稀濒危动物的调查研究

在南岳野生动物中,珍稀濒危动物共有28种,一级1种,即黄腹角雉TragopanCaboti;二级23种,其中哺乳类5种,鸟类15种,两栖类2种;中国生物多样性保护行动计划优先保护名录二级动物1种;中国优先保护动物中国特有种(A级)4种.本文主要介绍了它们的分类位置、形态特征和在我国的分布,根据南岳现有的资源状况,提出了保护措施与对策.     

不同品种蔬菜重金属污染评价和富集特征研究

运用单因子污染指数法和综合污染指数法,并通过因子分析和变异系数分析对17种不同的蔬菜品种进行了重金属污染评价和富集特征研究,以期在保证蔬菜安全生产的前提下为耕地资源的充分利用提供合理的建议。重金属污染评价结果表明,17个蔬菜品种中,污染程度处于安全的有4种:水东红灯笼脆甜芥菜(Brassica juncea(L.)Czern.et Coss.)、大坪铺大肉包心芥菜(Brassica juncea(L.)Czern.et Coss)、大坪铺中迟熟包心芥菜(Brassica juncea(L.)Czern.et Coss.)、南畔洲迟萝卜(Raphanus sativus);警戒线的有8种:四九31号油青甜菜心(Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee)、70d油菜心(Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee)、31号甜菜心(Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee)、玉兔5号青梗小白菜(Brassica pekinensis Rupr.),如意快菜(Brassica pekinensis Rupr.)、北京小杂56(Brassica pekinensis Rupr.)、荷兰豆(Pisum sativum)、短叶13号白萝卜(Raphanus sativus);轻度污染的有2种:60 d油菜心(Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee)、毛豆(Glycine max);中度污染的有2种:全年抗热油麦菜(Lactuca sativa var longifoliaf Lam.)、特选青梗莙荙菜(Beta vulgaris L.),重度污染的有1种:芫荽(Coriandrum sativum L.)。处于安全范围内的4种蔬菜品种可以作为该农田蔬菜安全生产的优选品种。因子分析表明,Cd是造成该批蔬菜重金属污染的主要因子。通过对该批蔬菜富集特征进行研究:不同品种蔬菜对Cr的富集差异较大,Cd次之,Pb、Hg和As则相对较小。17种蔬菜品种中,对Cr、Cd、Pb的富集系数最小的是萝卜1(南畔洲迟萝卜);对As富集系数最小的是芥菜1(精选水东红灯笼脆甜芥菜);对Hg富集系数最小的则有多种蔬菜,包括2种豆类(荷兰豆、毛豆)和2种萝卜(南畔迟萝卜、短叶13号白萝卜)。以上结果可以作为重金属低积累型蔬菜品种筛选的一个依据。     

5种喀斯特生境植物叶片解剖结构特征

对我国喀斯特地区几种不同生活型植物——常绿植物桂花(Osmanthus fragrans Lour.)、竹叶椒(Zanthoxylunarmatum DC),落叶植物红背山麻杆(Alchornea trewioides Muell.),草本植物石上莲(Oreocharis benthamii Clark var.reticulata Dunn),草本植物单枝竹(Monocladus saxatilis Chia,Fung et Y.L.Yang)的叶片形态解剖特征(叶片厚度、气孔密度、气孔结构等)进行了观察和测量,发现差异较大:竹叶椒角质层较厚,红背山麻杆的叶片较厚,单枝竹叶片上下表皮均有气孔,桂花气孔密度最高,石上莲的气孔纵径最长.结果表明:1)喀斯特生境植物存在着普遍的抗旱功能性解剖结构,用以适应喀斯特地区的特殊干旱气候;2)不同生活型植物对干旱选择的策略不同.表3参20     

大巴山国家地质公园珍稀濒危植物资源

珍稀濒危植物是生物多样性和生态系统的重要组成部分,考察研究特定地区的珍稀濒危植物对于区域生物多样性保护、生态环境质量评估及区域生态恢复都具有重要的意义。采用查阅资料、走访和路线踏勘结合植物群落样方调查等方法研究了四川大巴山国家地质公园的珍稀濒危植物种类组成和分布状况,并参照《中国种子植物区系》中划分的属的分布区类型,统计了珍稀濒危植物属的分布区类型及其在同类分布区中的占比,并探讨了该公园珍稀濒危植物的区系特征。结果表明,大巴山国家地质公园有珍稀濒危维管植物67种,隶属36科56属。被《国家重点保护野生植物名录》收录48种,其中Ⅰ级重点保护野生植物5种,Ⅱ级43种;被《中国植物红皮书》(第一批)收录的种类共45种,包括渐危种15种、濒危种7种及稀有物种14种,另有《中国植物红皮书》(第二批)8种。在这67种植物中,崖柏(Thuja sutchuensis)被列为世界自然保护联盟(International Union for Conservation of Nature,IUCN)红色植物名录的极危物种,另有濒危种6种,易危种7种,还有11种为近危或无危种。珍稀濒危植物区系成分复杂多样,共有10种分布区类型,属的分布区以温带成分为主,共41属,是热带成分的3倍之多。起源古老的孑遗物种丰富,且中国特有成分占了非常大的比例,以单型属和寡型属为主,单型属11属,寡种属7属,二者占总属数的32.1%。这与该公园古老的地质构造和奇特的地形地貌密切相关,古老的地质构造为珍稀植物提供了避难所,复杂奇特的地形地貌也为特有物种提供了生存环境。     

锌冶炼渣堆场优势植物的重金属累积特征研究

金属冶炼废渣未经处理露天堆存,经降雨和地表水的冲刷及风扬扩散,重金属会进入周围土壤和地下水,严重威胁周边自然生态环境和人体健康。以黔西北某锌冶炼厂的废渣堆场为研究对象,通过实地调查分析废渣堆场土壤和18种优势植物的重金属含量,研究优势植物对重金属的吸收、转运和富集特征,筛选出适应该地区生态修复的先锋植物。结果表明,该场地土壤Cd、Pb、Zn、Cu、Cr和Ni存在不同程度超标,以Cd、Pb、Zn污染最为严重,三者平均含量分别是贵州省土壤背景值的48、311、141倍。废渣场土壤受有效态Cd污染的风险较大,其生物有效性系数为49.12%。调查的优势植物均能适应废渣堆重金属元素较高的环境,对重金属具有一定的耐性。所有植物对重金属的吸收虽然都没有达到超临界植物规定的临界值,但植物体的重金属含量都远远超过了正常范围,且不同植物对重金属的吸收和蓄积特征不同。其中,鬼针草Bidens pilosa L.和土荆芥Chenopodium ambrosioides L.对Cd、Pb、Zn的吸收量大、运输能力强,且覆盖率高、生物量较大,对复合重金属具有一定的耐性,可以作为该地区生态恢复中的先锋物种。根据优势植物对重金属的富集和转运特征,研究区优势植物可分别富集型(如马刺蓟Cirsium monocephalum、蒲公英Taraxacum mongolicum Hand.-Mazz.和土荆芥Chenopodium ambrosioides L.)、根部囤积型(如牛筋草Eleusine indica(L.)Gaertn.、车前草Plantago asiatica L.和节节草Equisetum ramosissimum Desf)和规避型(如红花酢浆草Oxalis articulata Savigny)等3种类型。     

中国特有植物猪血木的濒危原因及保护对策

猪血木(Euryodendron excelsum H.T.Chang)为中国特有的山茶科单型属猪血木属的珍稀濒危植物,现仅分布于广东省阳春县八甲镇地区,且仅残存一个居群,居群内个体数量仅100余株,该物种已被列为国家二级保护植物。物种濒危原因分析是生物多样性保护的关键环节,文章从猪血木的地理分布、生活史特性、种群分布现状及生态环境因素影响等方面分析了该物种的濒危现状,猪血木种群地理分布的局限性限制了其空间拓展;种子萌发和幼苗生长对生境要求特殊和种群现状不利于其更新和发展,人为干扰对猪血木影响严重。其濒危的主要原因是人为因素引起的生境破碎化和过度砍伐所导致的个体数量下降,文章认为现存种群和生境的保护是濒危物种保护的最有效手段,针对猪血木的濒危现状和原因,提出了就地保护,促进自然种群的繁衍更新,建立猪血木繁育基地进行迁地保护和回归引种的保护策略,以期为猪血木的保护和种群恢复提供科学的理论指导,也为中国珍稀濒危物种和生物多样性的保护提供基础资料。     

10种园林植物功能性状对大气污染的生理生态响应

为了解植物叶功能性状对大气污染的响应,以兰州市安宁区(轻度污染区)和西固区(重度污染区)10种常见的园林植物圆柏(Sabina chinensis L.)、紫叶李(Prunus cerasifera Rehd.)、木槿(Hibiscus syriacus L.)、国槐(Sophorajaponica L.)、大叶黄杨(Buxus megistophylla Levl.)、雪松(Cedrus deodara G.)、云杉(Picea asperata Mast.)、月季(Rosa chinensis Jacq.)、紫叶矮樱(Prunus×cisterna N.E.)、旱柳(Salix matsudana Koidz.)为研究对象,运用单因素方差分析、相关性分析和冗余分析方法,对园林植物叶功能性状以及与大气污染的关系进行分析,以期为兰州市空气质量监测提供科学依据。结果表明,(1)随着大气污染浓度的增加,10种绿化植物的比叶面积(SLA)、可溶性糖(SS)以及可溶性蛋白(SP)含量显著下降,表现为安宁区西固区;叶干物质含量(LDMC)、丙二醛(MDA)以及脯氨酸(Pro)含量显著增大,表现为西固区安宁区。(2)10种园林绿化植物的叶功能性状间存在相对一致的相关性,SLA与LDMC之间存在极显著负相关性(P0.01),与Pro、SS及SP含量之间存在极显著正相关性(P0.01);LDMC和MDA含量呈极显著正相关性(P0.01),与SP含量呈极显著负相关性(P0.01);MDA含量与SP含量呈极显著负相关性(P0.01);SS含量与SP含量之间呈极显著正相关性(P0.01)。(3)冗余分析结果表明,植物叶功能性状受大气污染的影响大小为:ProMDALDMCSLASSSP,表明随大气污染程度的增加,植物Pro含量受大气环境的影响最大。     

中国东南部丹霞地貌区珍稀濒危保护物种的初步分析

根据野外调查和丹霞地貌申遗委员会提供的各丹霞地貌区的资料,中国东南部丹霞地貌区共有各类珍稀濒危保护植物178种,隶属于39科93属;其中国家重点保护植物27科,34属,41种,Ⅰ级5种,Ⅱ级36种;被中国植物红皮书<中国物种红色名录>(2004)收录128种,隶属33科、77属,极危2种,濒危7种,易危65种;被(2006)收录的植物共14科15属17种,濒危种(EN)3种、易危种(VU)6种,极危种(CR)1种;CITES(野生动植物保护国际贸易公约)收录的有5科,46属,107种.根据国家重点保护野生动物名录(1999),国家重点保护动物71种,其中Ⅰ级重点保护10种,Ⅱ级重点保护61种;被IUCN收录85种,其中,濒危种8种,易危种20种,极危种2种,其他为低危种;CITES收录100种,隶属于14目29科,其中单目单科单种的有5种;中国动物红皮书的动物有72种,其中,濒危种(EN)7种、易危种(VU)26种,极危种(CR)1种,其他为低危种.珍稀濒危动植物资源极其丰富.通过比较可以看出,丹霞地貌区的野生重点保护植物数目高于黄山、神农架、武夷山,与三清山的相近.但从被子植物的野生重点保护植物来看,要比黄山、武夷山丰富,说明了丹霞地貌植物区系的丰富性和独特性,丹霞山可能是历史变迁过程中一个重要的避难所.     

新记录的水蕨种群特征和群落的物种多样性

近几十年来,由于人类活动的影响,水蕨在我国的分布范围和种群数量正日趋减少,濒临灭绝,现被列为国家二级重点保护野生植物.根据标本记载和相关研究资料,于2003年8月至2006年10月,对分布在我国热带和亚热带的濒危植物水蕨进行广泛的野外调查.在每一调查点,用全球定位系统(GPS)测定了各样点的经纬度,记录了其生境特征和种群的生长状况,采集和鉴定水蕨及其主要伴生种,研究了其群落的结构特征.结果发现濒危植物水蕨的7个分布新记录.它们分别位于云南勐腊县郊区和勐仑、广东英德和阳春、浙江临安、海南三亚以及湖南郴州.新发现的水蕨种群主要生长在稻田或废弃稻田、水沟、菜地、旅游区.与水蕨相伴生的物种主要有11科15属17种,分别隶属于7个群丛.人类活动是导致水蕨濒危的主要原因.凭证标本均保存于武汉大学植物标本馆.     

南沙湿地公园红树林物种多样性与空间分布格局

红树林是海岸的特有植被类型,研究其物种多样性与空间分布,对红树林的恢复与保护具有重要意义。本文以南沙湿地公园红树林为典型案例,采用遥感影像解译和样方调查的方法,对红树林物种多样性、群落特征与空间分布格局进行研究。结果表明:(1)南沙湿地公园红树林物种多样性指数高于其他与之纬度相近的红树林群落;(2)以无瓣海桑Sonneratia apetala Buch-Ham.、桐花树Aegiceras corniculatum(L.)Blanco.、黄槿Hibiscus tiliaceus L.和芦苇Phragmites australis(Cav.)Trin.ex Steud.为优势种;(3)主要的群落类型为无瓣海桑群落、黄槿群落和芦苇群落等3种,总面积百分比达86.72%,无瓣海桑群落和黄槿群落面积占比分别为41.13%和36.44%,成为红树林的绝对优势群落;(4)红树林群落在空间上呈聚集态分布,聚集度最高的是无瓣海桑群落,其次是黄槿群落,面积占比最低的是木榄群落;(5)引进种无瓣海桑,发展态势好,抑制了乡土种红树植物生长。建议扩种白骨壤Avicennia marina(Forsk.)Vierh.、桐花树和秋茄Kandelia candel(L.)Druce.,扩大其斑块面积,以提升乡土红树植物群落的稳定性,达到有效保护红树林的目的。     

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.