贵州喀斯特山区植物营养元素含量特征

贵州喀斯特山区是我国乃至世界喀斯特分布面积最大的片区之一,由于其生态系统的脆弱性,加之人类活动的干扰,使得该区的植被退化较为严重。文章选择该区的12种主要植物作为研究对象,对其营养元素进行了研究。结果表明:>1000μg·g-1的元素有N、P、K、Ca、Mg、S,100～1000μg·g-1的元素有Fe、Mn、Al,10～100μg·g-1的元素有Zn、Sr,<10μg·g-1的元素为Cu、Mo,其中Mo含量最低,仅为0.17μg·g-1。这些元素中,Ca、P、K元素高于所报道的陆生植物的含量范围。元素含量特点是Ca>K>Mg型。N、P、K、Mg元素的频数分布为正态分布,Ca、Al、Fe、Mn、Cu、Zn、Sr、S元素为对数正态分布。变异系数大于100%的元素有Al、Fe、Mn、Sr,变异系数小于60%的元素有N、P、K、Ca、Mg、S、Cu,其中Ca的变异系数最小,仅为11.8%。不同生境下相同植物的营养元素含量有较大的差异,石灰土上植物的N、P、K、Ca、Mg、Al、Cu、Mo元素含量要高于黄壤上植物的。元素间的相关分析表明:P和K、P和Cu、Al和Fe、Al和Zn、Fe和Zn元素具有显著相关关系;N和P、P和Mg、K和Al、K和Cu、Ca和Sr、S和Mo元素具有一般相关关系。     

不同地区何首乌无机元素含量的比较

采用ICP法测定了不同地区何首乌植物及其生境土壤中的15种元素(Al、B、Ba、Ca、Cu、Fe、K、Mg、Mn、Na、Ni、P、Sr、Ti、Zn),分析比较了各种元素在不同地区何首乌体内和生境土壤中的分布规律及不同地区何首乌对无机元素的吸收富集能力.结果表明,不同地区何首乌和土壤中无机元素含量存在着显著差异,德庆、井冈山、靖西三地何首乌的Mn含量较高;不同地区何首乌对元素的富集系数无显著性差异,而何首乌对不同无机元素的富集系数则有显著差异,主要表现在对Ca、K、Mg、Sr的吸收富集能力较强.表6参14     

不同攀援角度裂叶牵牛叶片金属元素含量变化及其相关性分析

为研究攀援角度对藤本植物金属元素含量的影响,采用原子吸收分光光度法测定了不同攀援角度裂叶牵牛叶片中10种金属元素含量,并对金属元素含量的相关性进行了分析.结果表明:攀援角度处理对裂叶牵牛叶片的金属元素含量产生不同程度的影响.攀援角度对Ca、K、Mg、Fe、Mn、Zn、Cd含量影响显著.大量元素对攀援角度的敏感性小于微量元素.随攀援角度增加(从0°到90°攀援角),叶片Mg、Zn和Mn含量显著增加,而Cd含量显著下降;K、Ca、Na和Fe含量呈"U"型变化趋势;从30°到90°攀援角,Pb含量呈增加趋势;Cu含量的变化规律不明显.相关分析表明,攀援角度与Mg、Zn、Mn含量呈显著的正相关,与Cd含量呈显著负相关;攀援角度与Ca、Na、K、Fe、Cu和Pb含量之间的相关性未达到显著水平.10种金属元素中呈正相关的元素多于负相关元素.其中,Mg、Zn、Mn和Cd在金属元素之间的协同或拮抗中发挥主要作用.     

广西热带亚热带典型森林岩溶区土壤-植物系统元素分布特征

对广西热带亚热带典型岩溶区土壤-植物系统13种元素分布特征及相关性进行了研究.结果表明:与非岩溶区植物相比,岩溶植物Ca、Al含量比较高,Na、Fe、Mn、Si、K、P的含量较低.植物体内元素的分布特点是:叶>茎>根;石灰土更易富集Fe、P、K、Cu、Zn和Co.大多数土壤元素含量随纬度的降低而降低,Fe和Zn表现较为明显,而Mn和Si在热带较中亚热带的更易淋失.土壤中与Fe元素明显相关的元素最多,包括Mn、Zn、Co、S、Al,其相关性分别为Mn> Al > Co > Zn > S,其中,Fe与Mn、S呈负相关,与Zn、Co、Al呈正相关;植物中的Na、Fe、Si、P、Al与土壤中对应的元素相关性显著,呈正相关关系,主要体现在土壤的A层;植物对大量元素的吸收强于对微量元素的吸收,其中,对Mn的吸收能力最强(8229.38%),主要集中在根部的Al(0.57%)和Fe(0.0049%)的吸收能力最小.     

新疆博尔塔拉河湖流域土壤元素空间变异性及其影响因素

中国西北干旱区是典型的温带大陆性干旱气候区,随着人口增多、工农业的迅速发展,人类活动产生的污染物日愈增多,区域土壤环境安全受到威胁。为了解西北干旱区典型河湖流域表层土壤元素的空间变异性,利用经典统计学及地统计分析对博尔塔拉河湖流域地表40个采样点土壤样品中19种元素的空间变异特征及其影响因素进行分析,并通过富集系数法和Hakanson潜在生态风险指数法对重金属潜在生态风险进行评价。博尔塔拉河流域表层土壤样品中Ba、Mn、V、Pb、Cr、Co、Ni、Cu等元素含量平均值均低于新疆表层土壤元素背景值,其他元素含量平均值均偏高。通过系统聚类分析,可将19种元素分为二组:第一组元素主要包括Al、K、Be、Fe、Co、Cr、Mn、V、Ti、Ba、P、Zn、Pb、Cu、Ni等元素,其中Al、K、Be、Fe、Co、Cr、Mn、V、Ti、Ba等元素为第一亚组,元素P单独为第二亚组,重金属Zn、Pb、Cu、Ni为第3亚组;第2组元素为Ca、Sr、Mg和Na,其中,Ca、Sr、Mg等表生环境中地球化学性质较为活跃的元素为第四亚组,Na单独为第五亚组。地统计学分析表明,Al、Fe、K、Ti、Ba、Be、Mn、V、Ti、Ba等稳定性元素表现为中等或较强的空间自相关。元素P和重金属元素Zn、Pb、Ni、Cu由于受到局部随机因素如耕作施肥、交通、工农业生产等小尺度因素影响,空间结构较为复杂,但整体上还没有破坏区域原有的空间格局。Ca、Mg、Sr在表生环境中地球化学活性较强,除受区域整体自然环境的控制外,还容易受人为耕作、径流等因素的影响导致空间结构性较差。Na由于受到区域自然环境变化和人为耕作的影响,空间结构性较差。最后通过富集系数计算得出研究区Co、Cr、Cu、Ni、Pb、V和Zn等7种重金属的富集系数平均值均低于1.5,表明虽然受到人为活动影响,但富集程度较低。Hakanson潜在生态风险指数分析表明,7种重金属的riE值范围在0.8~25.7之间,平均值均小于5,为轻微污染风险。综合生态风险指数RI值表明博河流域表层土壤中重金属总体处于轻微污染风险水平,但局部采样点仍然存在中等生态风险程度。     

太湖梅梁湾水体悬浮颗粒物中重金属的含量

用ICP—AES方法测定太湖梅梁湾水体悬浮颗粒物中的Co,Cr,Cu,Ni,Pb,Zn等重金属元素,以及Al,Ba,Be,Ca,Fe,K,Mg,Mn,Na,Sr,Ti,V等相关金属元素的含量,并分析了沉积物中相关元素的含量和分布特征．悬浮物中Cr,Cu,Mn,Ni,Zn的含量显著高于表层沉积物,Al,Ba,Be,Ca,Co,Fe,K,Mg,Pb,V等元素的含量高出表层沉积物10％-30％,Sr和Ti与沉积物中的含量相当,Na的含量则显著低于沉积物．重金属元素在悬浮物中表现出较强的富集作用．从污水入湖口到湾心,悬浮物中Cr,Cu,Pb,Zn含量呈明显降低的趋势,反映出直湖港对太湖的污染作用仍十分严重．但沉积物中重金属含量并未表现出自港口到湾心显著降低的趋势,说明该区域沉积物对水体重金属污染的记录信息可能失真．水体悬浮物的重金属含量可以很好地反映水体的污染状况及其潜在的生态效应．     

厦门市大气降尘中重金属形态分布及生物有效性

采集了2012年11月至2013年1月期间厦门市大气降尘样品,用改进的BCR四步连续提取法分析了12种重金属元素(Ba、Ti、Co、Cr、Cu、Fe、Mn、Zn、Ni、Pb、Sr、V)的含量、赋存形态和生物有效性.结果显示,重金属元素四态含量之和均值(mg·kg~(-1))顺序为:Fe(43733)Zn(4495)Ti(2728)Ba(747)Mn(723)Cu(444.4)Sr(176)Cr(171)Pb(160)Ni(40.4)V(27.6)Co(11.2);Zn和Cu含量分别为我国土壤环境质量标准第二类标准限值(250和100 mg·kg~(-1))的18倍和4.4倍;除Fe、Ti、Ba、Cr和V外,大气降尘中其他元素生物有效态含量占有相当的比例(32.2%—88.6%).Zn、Sr主要以弱酸溶态存在,Pb主要以可还原态存在,Cu主要以可氧化态存在,其余元素主要以残渣态存在.大气降尘中重金属的平均生物有效性系数顺序为:Sr(0.87)Zn(0.85)Cu(0.80)Pb(0.67)Mn(0.50)Co(0.47)Ni(0.39)Ba(0.19)≈Cr(0.19)V(0.12)Fe(0.08)Ti(0.01),Ti、Fe、V、Cr和Ba为生物不可利用元素,Ni、Co、Mn和Pb为潜在生物可利用元素,Cu、Zn和Sr为生物可利用元素.     

规模化养殖场鸡粪营养物质和污染元素的组成特点

营养物质和有害元素的状况直接影响畜禽粪的利用价值.从浙江省代表性规模化养殖场收集19个鸡粪样,分析其营养物质、污染元素含量及P、Cu、Zn的化学形态.结果表明,鸡粪中含有较为丰富的粗蛋白和矿物质,但同时也含有较高量的Cu、Zn及可溶性盐分.鸡粪中P、Cu和Zn主要以可提取态存在,有较高的生物有效性和移动性.鸡粪中微量元素和重金属含量明显高于饲料,并受饲料中相应元素含量的影响;鸡粪与饲料之间的Ca、Mg、P、K、As、Cd、Cr、Cu、Fe、Mn、Pb和Zn含量显著相关,饲料质量是影响鸡粪重金属元素含量的主要因素.     

冀北山地山杨桦木林生态系统水化学特征研究

降水是森林生态系统的一个主要的养分输入源,观测并分析降水化学对于准确地估算森林生态系统养分循环的养分元素浓度与量显得极为重要。对冀北山地山杨桦木林穿透雨、树干茎流和枯透水中的Ca、Fe、K、Mg、Mn、Zn共6种养分元素进行了测定。结果表明：（1）大气降水经过林冠层后其水化学特征明显发生了变化,化学元素含量均有不同程度增加,化学元素含量排序为Ca〉K〉Mg〉Fe〉Mn〉Zn,其中Mn元素的增长倍数最多。树干径流各项指标均增长很多,化学元素含量排序为K〉Ca〉Mg〉Fe〉Mn〉Zn。枯落物水中K和Ca元素浓度增加最大。（2）大气降雨中Zn的变异系数最大,达2.853;K和Ca元素的变异系数最小,为0.158、0.163。穿透雨、树干茎流和枯透水中最大变异系数分别为Mn元素0.717、Zn元素为1.588、Fe元素为0.553。（3）经过淋洗后水样中各元素的浓度均有所增加,穿透水、树干径流和枯透水中K、Ca增加较多,Fe、Zn的淋溶量较少。     

内蒙古羊草草原植物营养元素的含量特征

植物对营养元素的吸收利用是生态系统物质循环的关键过程,同时也是退化草地生态系统恢复和重建的重要问题。为探讨草原生态系统植物对元素的吸收利用规律,在内蒙古锡林河流域的羊草草原选取羊草(Leymus chinensis、冰草(Agropyron cristatum)、大针茅(Stipa grandis)、西伯利亚羽茅(Achnatherum.sibirica)、芯芭(Cymbaria dahurica.)、洽草(Koeleria cristata)等11种主要植物为研究对象,分析比较了10种营养元素的含量特征。结果表明,(1)研究区主要植物各元素含量特征属于w(K)w(Ca)w(Mg)型。元素的变异系数均小于1,元素种间差异不显著。(2)相关性分析表明,C和Fe、C和Cu、N和K、N和Mg、P和K、P和Mg、Ca和Mg、Fe和Cu均为极显著相关(P≤0.01),C和Fe、C和Cu是负相关,其它均为正相关;N和P、N和Ca、K和Mg显著正相关(P≤0.05)。(3)禾本科植物具有低N-P-K-Ca特征,Fe、Cu元素含量较高,非禾本科物种Mn、Zn、P、Mg、Ca、K、N、C元素含量较高,其中Ca、K、Mg元素达到极显著差异(P≤0.01),N达到显著差异(P≤0.05)。(4)利用主成分分析法对植物营养元素水平进行综合评价,表明芯芭、洽草、菊叶委陵菜的营养元素含量水平较高,吸收营养元素的能力较强。     

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     

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.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Sequestration of cucurbitacin analogs by New and Old World chrysomelid leaf beetles in the tribe Luperini

Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.     

Effects of Controlled Fire and Livestock Grazing on Bird Communities in East African Savannas

Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture     

What Every Conservation Biologist Should Know about Economic Theory

Abstract: The last century has seen the ascendance of a core economic model, which we will refer to as Walrasian economics. This model is driven by the psychological assumptions that humans act only in a self‐referential and narrowly rational way and that production can be described as a self‐contained circular flow between firms and households. These assumptions have critical implications for the way economics is used to inform conservation biology. Yet the Walrasian model is inconsistent with a large body of empirical evidence about actual human behavior, and it violates a number of basic physical laws. Research in behavioral science and neuroscience shows that humans are uniquely social animals and not self‐centered rational economic beings. Economic production is subject to physical laws including the laws of thermodynamics and mass balance. In addition, some contemporary economic theory, spurred by exciting new research in human behavior and a wealth of data about the negative global impact of the human economy on natural systems, is moving toward a world view that places consumption and production squarely in its behavioral and biophysical context. We argue that abandoning the straightjacket of the Walrasian core is essential to further progress in understanding the complex, coupled interactions between the human economy and the natural world. We call for a new framework for economic theory and policy that is consistent with observed human behavior, recognizes the complex and frequently irreversible interaction between human and natural systems, and directly confronts the cumulative negative effects of the human economy on the Earth's life support systems. Biophysical economics and ecological economics are two emerging economic frameworks in this movement.