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111.
Maintenance of biodiversity through seed banks and botanical gardens, where the wealth of species’ genetic variation may be preserved ex situ, is a major goal of conservation. However, challenges can persist in optimizing ex situ collections if trade-offs exist among cost, effort, and conserving species evolutionary potential, particularly when genetic data are not available. We evaluated the genetic consequences of population preservation informed by geographic (isolation by distance [IBD]) and environmental (isolation by environment [IBE]) distance for ex situ collections for which population provenance is available. We used 19 genetic and genomic data sets from 15 plant species to assess the proportion of population genetic differentiation explained by geographic and environmental factors and to simulate ex situ collections prioritizing source populations based on pairwise geographic distance, environmental distance, or both. Specifically, we tested the impact prioritizing sampling based on these distances may have on the capture of neutral, functional, or putatively adaptive genetic diversity and differentiation. Individually, IBD and IBE explained limited population genetic differences across all 3 genetic marker classes (IBD, 10–16%; IBE, 1–5.5%). Together, they explained a substantial proportion of population genetic differences for functional (45%) and adaptive (71%) variation. Simulated ex situ collections revealed that inclusion of IBD, IBE, or both increased allelic diversity and genetic differentiation captured among populations, particularly for loci that may be important for adaptation. Thus, prioritizing population collections based on environmental and geographic distance data can optimize genetic variation captured ex situ. For the vast majority of plant species for which there is no genetic information, these data are invaluable to conservation because they can guide preservation of genetic variation needed to maintain evolutionary potential within collections. 相似文献
112.
Identification of policies for a sustainable legal trade in rhinoceros horn based on population projection and socioeconomic models
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Enrico Di Minin Jussi Laitila Federico Montesino‐Pouzols Nigel Leader‐Williams Rob Slotow Peter S. Goodman Anthony J. Conway Atte Moilanen 《Conservation biology》2015,29(2):545-555
Between 1990 and 2007, 15 southern white (Ceratotherium simum simum) and black (Diceros bicornis) rhinoceroses on average were killed illegally every year in South Africa. Since 2007 illegal killing of southern white rhinoceros for their horn has escalated to >950 individuals/year in 2013. We conducted an ecological–economic analysis to determine whether a legal trade in southern white rhinoceros horn could facilitate rhinoceros protection. Generalized linear models were used to examine the socioeconomic drivers of poaching, based on data collected from 1990 to 2013, and to project the total number of rhinoceroses likely to be illegally killed from 2014 to 2023. Rhinoceros population dynamics were then modeled under 8 different policy scenarios that could be implemented to control poaching. We also estimated the economic costs and benefits of each scenario under enhanced enforcement only and a legal trade in rhinoceros horn and used a decision support framework to rank the scenarios with the objective of maintaining the rhinoceros population above its current size while generating profit for local stakeholders. The southern white rhinoceros population was predicted to go extinct in the wild <20 years under present management. The optimal scenario to maintain the rhinoceros population above its current size was to provide a medium increase in antipoaching effort and to increase the monetary fine on conviction. Without legalizing the trade, implementing such a scenario would require covering costs equal to approximately $147,000,000/year. With a legal trade in rhinoceros horn, the conservation enterprise could potentially make a profit of $717,000,000/year. We believe the 35‐year‐old ban on rhinoceros horn products should not be lifted unless the money generated from trade is reinvested in improved protection of the rhinoceros population. Because current protection efforts seem to be failing, it is time to evaluate, discuss, and test alternatives to the present policy. 相似文献
113.
114.
广州城市生态环境变化 总被引:5,自引:0,他引:5
对广州城市生态环境因子的大气,水,固体废弃物和噪声污染状况近十年数据结合广州城市发展,分析其环境污染变化特征,结果表明,广州市大气环境污染已由煤烟型向石油型转变;环境中有机污染严重,主要表现为氨氮,BOD5,砷化物和汞化物污染,固体垃圾产出量逐年增加,声环境在逐步好转。 相似文献
115.
Felicita?ScapiniEmail author Lorenzo?Chelazzi Isabella?Colombini Mario?Fallaci Lucia?Fanini 《Marine Biology》2005,147(4):919-926
Orientation experiments were carried out on Talitrus saltator (Crustacea Amphipoda) at four points along 3 km on a dynamic sandy beach inside the Maremma Regional Park (Grosseto, Italy) to highlight behavioural variation related to distance from a river mouth, to erosion or accretion of shoreline, and to human trampling on the beach. Tests were performed using circular transparent Plexiglas arenas, contemporaneously at the four points. Replicates were made in 2 different months (September 2002 and May 2003), on 2–3 successive days, in the morning and afternoon. The distributions of the angles of orientation were compared for the different points and seasons, and multiple regression analysis was performed to test the effects of environmental and intrinsic variables on orientation. Sandhoppers showed the highest scatter at the eroded shoreline, intermediate scatter at the accreting beach most distant from the river mouth, and consistent orientation seaward at the least disturbed point. Orientation of sandhoppers was significantly affected by season, global radiation, time of day, distance from the river mouth, and human trampling. Sex and air humidity were of minor significance in the multiple regression model. The results, on the one hand, confirm plasticity in orientation of sandhoppers living on a dynamic shoreline, and on the other hand, show that variation in orientation could potentially be used as a bioindicator of shoreline changes.Communicated by R. Cattanevo-Vietti, Genova 相似文献
116.
Mario F. Teisl Brian Roe Robert L. Hicks 《Journal of Environmental Economics and Management》2002,43(3):339
In this paper we test whether the dolphin-safe labels altered consumer purchases of tuna. We also provide a partial measure of the total welfare effects of the dolphin-safe labeling policy. The results confirm our hypothesis that the dolphin–tuna controversy and the subsequent implementation of dolphin-safe labeling affected consumer behavior. Further, the paper provides market-based evidence that consumers can respond to eco-labels; the dolphin-safe label increased the market share of canned tuna. The welfare analysis provides a partial measure of society's willingness to pay to avoid personally contributing to dolphin mortality as a result of tuna fishing. 相似文献
117.
Summary. We report field and laboratory evidence indicating that the defensive compounds secreted by the millipedes Amplinus bitumidus (Diplopoda: Polydesmida) and Anadenobolus putealis (Diplopoda: Spirobolida) attract the carrion scarab Canthon morsei (Scarabaeidae: Scarabaeinae). In a Mexican tropical rain forest, C. morsei was mostly caught in pitfall traps baited with the carcasses of both millipede species. Only a few beetles were attracted
to fish carrion. Experimental evidence indicates that C. morsei is attracted to freshly dead millipedes. Benzaldehyde and HCN were identified from Amplinus bitumidus; but 2-methyl-1,4-benzoquinone (toluquinone) and 2-methoxy- 3-methyl-1,4-benzoquinone from Anadenobolus putealis. Benzaldehyde attracted significantly more C. morsei individuals than fish meat, or millipedes of both species did after rinsing in hexane. This is the first report of Polydesmida
attracting dung beetles. 相似文献
118.
Tal Svoray Shiri Bar-Yamin Gancharski Zalmen Henkin Mario Gutman 《Ecological modelling》2004,180(4):537-556
Herbaceous plant production plays a key role in determining the function of rangeland ecosystems in the semi-arid and Mediterranean regions. Therefore, assessment of herbaceous plant habitats is important for understanding the ecosystem functioning in these regions and for applied purposes, such as range management and land evaluation. This paper presents a model to assess herbaceous plant habitats in a basaltic stony environment in a Mediterranean region. The model is based on geographic information systems (GIS), remote sensing and fuzzy logic, while four indirect variables, which represent major characteristics of herbaceous habitats, are modeled: rock cover fraction; wetness index (WI); soil depth; and slope orientation (aspect). A linear unmixing model was used to measure rock cover on a per pixel basis using a Landsat TM summer image. The wetness index and local aspect were determined from digital elevation data with 25 m × 25 m pixel resolution, while soil data were gathered in a field survey. The modeling approach adopted here is process-based and assumes that water availability plays a crucial role in determining herbaceous plant production in Mediterranean and semi-arid environments. The model rules are based on fuzzy logic and are written based on the hypothesized water requirements of the herbaceous vegetation. The results show that on a polygon basis there is positive agreement between the model proposed here and previous mapping of the herbaceous habitats carried out in the field using traditional methods. Intrapolygon tests show that the use of a continuous raster data model and fuzzy logic principles provide an added value to traditional mapping. Moreover, herbaceous biomass measurements at two time intervals—mid- and peak winter season—corresponded with the habitat assessment predictions achieved using a new scenario that is proposed in this research. This scenario suggests that rockiness increases herbaceous production on south-facing slopes, while in other slope aspects the rock cover has lower impact on herbaceous growth. Due to its simplicity, the model suggested here can be used by planners and managers, to adjust range activities over large areas. The process-based approach should allow adaptation of the model to other regions more effectively than models that were formulated on a purely empirical basis. The model could also be used to study the relationship between water availability and ecosystem productivity on a regional scale. 相似文献
119.
Tonio Di Battista 《Environmental and Ecological Statistics》2003,10(1):83-93
In many surveys in environmental and natural phenomena the aim is to evaluate the heterogeneity, and the skewness of the distribution of the number point-objects in the study area opportunely partitioned in sub-regions. For this purpose, in this paper the estimation of dispersion indices is considered by using simple random sampling and adaptive sampling with initial simple random sampling selected with replacement or without replacement. The jackknife and the bootstrap procedures are proposed in both cases for reducing bias. Finally, both a simulation study and a case study on biological population referred to a Oidium tuckeri contamination in a growing vineyard is performed to assess the accuracy of the proposed estimators. 相似文献
120.
以质量比9∶1的活性炭和乙炔黑制备气体扩散电极,着重研究电流密度、pH值、曝气量等因素对H2O2产生量的影响.结果表明:pH值在较大范围内均适用;电流密度控制在50~75 mA/cm2,曝气量确定为5 L/min时,反应产生H2O2较多.另外,利用该气体扩散电极做阴极,石墨电极做阳极,以Na2SO4为电解质,研究了电解时间、电流密度、pH值、初始苯酚浓度、曝气量等因素对苯酚降解效果的影响.结果表明:在电流密度为75 mA/cm2、曝气量为5 L/min、初始pH=3的条件下,当苯酚的初始浓度为80 mg/L时,1 h后其去除率达77%. 相似文献