Spatial-temporal patterns in Mediterranean carnivore road casualties: Consequences for mitigation

Many carnivores have been seriously impacted by the expansion of transportation systems and networks; however we know little about carnivore response to the extent and magnitude of road mortality, or which age classes may be disproportionately impacted. Recent research has demonstrated that wildlife-vehicle-collisions (WVC) involving carnivores are modulated by temporal and spatial factors. Thus, we investigated road mortality on a guild of small and medium-sized carnivores in southern Portugal using road-kill data obtained from a systematic 36 months monitoring period along highways (260 km) and national roads (314 km) by addressing the following questions: (a) which species and age class are most vulnerable to WVC? (b) are there temporal and/or spatial patterns in road-kill? and (c) which life-history and/or spatial factors influence the likelihood of collisions? We recorded a total of 806 carnivore casualties, which represented an average of 47 ind./100 km/year. Red fox and stone marten had the highest mortality rates. Our findings highlight three key messages: (1) the majority of road-killed individuals were adults of common species; (2) all carnivores, except genets, were more vulnerable during specific life-history phenological periods: higher casualties were observed when red fox and stone marten were provisioning young, Eurasian badger casualties occurred more frequently during dispersal, and higher Egyptian mongoose mortality occurred during the breeding period; and (3) modeling demonstrated that favorable habitat, curves in the road, and low human disturbance were major contributors to the deadliest road segments. Red fox carcasses were more likely to be found on road sections with passages distant from urban areas. Conversely, stone marten mortalities were found more often on national roads with high of cork oak woodland cover; Egyptian mongoose and genet road-kills were found more often on road segments close to curves. Based on our results, two key mitigation measures should help to reduce WVC in Portugal. The first involves the improvement of existing crossings with buried and small mesh size fence to guide the individuals towards to the passages, in road segments with high traffic volume (>1200 vehicles/night) and located in preferred carnivore habitats. The second mitigation involves cutting or removal of dense vegetation in verges of road segments with curves to aid motorists in seeing animals about to cross.     

Simple modelling to assess if offsets schemes can prevent biodiversity loss, using examples from Australian woodlands

Offset schemes are advocated as a way that continued development and environmental restoration can be achieved concurrently. We used a simple modelling approach to evaluate proposed offsets schemes, with scenarios that required offsetting the impacts of clearing woodlands either by revegetation of cleared land or by improving the habitat value of degraded woodland. Each simulation used the attribute table of a single GIS polygon layer to obtain data and record results. We investigated the likely consequences of these schemes for three groups of species with different foraging resource requirements: shrub-dependent; canopy-dependent and old tree-dependent. Only the shrub-dependent group, whose requirements could be rapidly grown, saw increases in suitable habitat in the landscape within our 30 year simulations. The habitat of the canopy-dependent group initially declined but began to increase towards the end of some simulations, while the old tree-dependent group’s habitat declined. When a simple measure of spatial configuration was considered further differences between the schemes were highlighted. The simulation results demonstrate that assessing only the eventual benefit score of a scheme can hide the losses sustained by some elements of biodiversity. We recommend this type of simple modelling approach as the first step in determining whether a proposed offsets scheme is worth investigating further. In particular, the ability to represent the scheme’s predicted consequences as maps and graphs assists decision makers in judging whether the scheme has sufficient merit to warrant a full assessment and subsequent implementation; or needs some adjustments to achieve its aims, or is seriously flawed.     

Effect of urease and nitrification inhibitors on N transformation, gaseous emissions of ammonia and nitrous oxide, pasture yield and N uptake in grazed pasture system

Nitrogen (N) losses via nitrate (NO₃⁻) leaching, ammonia (NH₃) volatilization and nitrous oxide (N₂O) emissions from grazed pastures in New Zealand are one of the major contributors to environmental degradation. The use of N inhibitors (urease and nitrification inhibitors) may have a role in mitigating these N losses. A one-year field experiment was conducted on a permanent dairy-grazed pasture site at Massey University, Palmerston North, New Zealand to quantify these N losses and to assess the effect of N inhibitors in reducing such losses during May 2005-2006. Cow urine at 600 kg N ha⁻¹ rate with or without urease inhibitor N-(n-butyl) thiophosphoric triamide (nBTPT) or (trade name “Agrotain”) (3 L ha⁻¹), nitrification inhibitor dicyandiamide (DCD) (7 kg ha⁻¹) and the use of double inhibitor (DI) containing a combination of both Agrotain and DCD (3:7) were applied to field plots in autumn, spring and summer. Pasture production, NH₃ and N₂O fluxes, soil mineral N concentrations, microbial biomass C and N, and soil pH were measured following the application of treatments during each season. All measured parameters, except soil microbial biomass C and N, were influenced by the added inhibitors during the three seasons. Agrotain reduced NH₃ emissions over urine alone by 29%, 93% and 31% in autumn, spring and summer respectively but had little effect on N₂O emission. DCD reduced N₂O emission over urine alone by 52%, 39% and 16% in autumn, spring and summer respectively but increased NH₃ emission by 56%, 9% and 17% over urine alone during those three seasons. The double inhibitor reduced NH₃ by 14%, 78% and 9% and N₂O emissions by 37%, 67% and 28% over urine alone in autumn, spring and summer respectively. The double inhibitor also increased pasture dry matter by 10%, 11% and 8% and N uptake by the 17%, 28% and 10% over urine alone during autumn, spring and summer respectively. Changes in soil mineral N and pH suggested a delay in urine-N hydrolysis with Agrotain, and reduced nitrification with DCD. The combination of Agrotain and DCD was more effective in reducing both NH₃ and N₂O emissions, improving pasture production, controlling urea hydrolysis and retaining N in NH₄⁺ form. These results suggest that the combination of both urease and nitrification inhibitors may have the most potential to reduce N losses if losses are associated with urine and improve pasture production in intensively grazed systems.     

Monitoring the impacts of mountain pine beetle mitigation

Since 1999, the mountain pine beetle (Dendroctonus ponderosae Hopk. [Coleoptera: Scolytidae]) has impacted over 13 million hectares of pine forests in western Canada. Successful mitigation of the beetle depends on the accurate and timely identification of currently infested trees and on sustained control activities over several successive years. We monitored the success of mitigation activities in reducing damage caused by mountain pine beetle at two sites (A and B) on the leading edge of the current beetle epidemic in western Canada. Using three years of digital high spatial resolution aerial imagery (2006–2008) and one season of field measurements (2008), we estimated retrospective ratios of trees attacked by beetle in the current year (green attack) to trees attacked in the previous year (red attack), hereafter referred to as G:R. Our results indicate that mitigation activities slowed the rate of population growth, with G:R found to be decreasing or stable over sites A and B while mitigation was ongoing in 2005 and 2006 (site A 1.06:1; site B 0.32:1). When mitigation was discontinued over site A in 2007, the G:R increased markedly (1.94:1), while continued mitigation at site B in 2007 further reduced the G:R (0.22:1). Despite the cost associated with mitigation, its efficacy is rarely assessed and even more rarely documented. The approach presented herein enables a sample-based appraisal of mitigation efforts.     

发展有机农业对缓解气候变化的作用

农业生态系统中的碳库是全球碳库中最活跃的部分,土壤可以通过团聚体-有机物的固碳作用降低大气中CO2浓度,从而缓解气候变暖。有机农业因其只施用有机肥、对土壤的保护性开发利用,不仅能够改善土壤形成和结构,增加养分和能量循环,而且与常规农业相比土壤的固碳能力有所增强,对缓解气候变化起到积极的作用,保护生态环境,维持农业的可持续发展。因此,发展有机农业能够实现结构优化、产业产品升级,是新时期农业和农村经济发展的方向,能够真正实现环境、经济和社会效益的完美结合。但同时,我国现阶段发展有机农业还存在很多难题,需要加大研发和宣传力度,更好地发展有机农业。     

Integrated weight longlines with paired streamer lines - Best practice to prevent seabird bycatch in demersal longline fisheries

To evaluate a new technology - integrated weight longlines (IW) - as a viable seabird mitigation technology for demersal longline fisheries, we compared three experimental mitigation treatments, IW line alone, IW with paired streamer lines (IWPS) and unweighted longlines (UW) with PS (UWPS), to a control of no deterrent (UW alone). Trials took place on two vessels targeting Pacific cod (Gadus macrocephalus) over a five-month period in the Bering Sea, Alaska, USA. We used multiple criteria for evaluations - catch rates of all taxa, seabird abundance and attack rate, and gear sink rate and performance - making this study the largest and most comprehensive experiment of its kind.All mitigation technologies dramatically decreased seabird bycatch rates while having little to no effect on fish catch rates. Mitigation was more effective for surface foraging seabirds (Fulmarus glacialis and Larus spp.) than for diving seabirds (short-tailed shearwaters, Puffinus tenuirostris), reducing mortality rates by 91-100% and 80-97%, respectively. Based on multiple criteria, IWPS performed best, sinking gear within the protection of streamer lines eliminating surface forager catch completely and reducing shearwater catch by 97%, relative to the control. UWPS, status quo in the Alaska fishery, and IW alone performed similarly reducing surface forager catch rates by 98% and 91%, respectively, and shearwater rates by 87% and 80%, respectively. Seabird abundance and attack rate were poor proxies of seabird mortality, especially for IW gear. IW lines reduced the distance astern that birds have access to sinking baits by near half and its handling qualities proved superior to UW. We conclude that IW longlines and paired streamer lines are the core mitigation techniques and when deployed together, constitute the best management practice for seabird conservation in demersal longline fisheries using autoline systems.     

Options for increasing carbon sequestration in West African soils: an exploratory study with special focus on Senegal

The organic matter content of many soils in West Africa has been depleted due to overgrazing, agricultural mismanagement, deforestation and overexploitation of the natural resources. Degraded agro(eco)systems can be managed to increase carbon sinks in vegetation and soil, and to reduce carbon emissions to the atmosphere. The capacity for sequestering carbon will increase as annual precipitation increases, and generally as mean temperature decreases, provided the soil and terrain conditions are not limiting for crop (biomass) growth. The agroecological suitability of three pilot sites, proposed for soil carbon sequestration projects in Senegal, is assessed and the feasibility of various management options to increase organic carbon levels in the soil is discussed. For the future, a Land Resources Information System should be developed to consider detailed data on climate, soil and terrain conditions, status of soil degradation, and land‐use systems for West Africa. Upon its linkage to a dynamic soil carbon model and a socio‐economic module, such an integrated system can be used to assess the ecotechnological and socio‐economic potential for carbon sequestration projects in the context of the Clean Development Mechanism (CDM) proposed under article 12 of the Kyoto Protocol to the United Nations Framework Convention on Climate Change. If adopted, this mechanism could confer funds to West African countries for the sustainable use and conservation of their natural resources, thereby providing economic, environmental and societal benefits for local populations, while simultaneously contributing to climate change mitigation. Copyright © 2001 John Wiley & Sons, Ltd.     

河北省沿海赤潮的成因及调控对策研究

赤潮是河北省沿海地区主要海洋生态灾害之一。对河北省沿海赤潮的成因进行了剖析并提出调控对策。研究表明：河北省沿海赤潮发生的内因是存在赤潮生物;外因是具备适宜的环境条件,如近海海域富营养化、适量的微量元素和有机物以及水文、气象和海水理化因子的变化等。     

新型期权模型研究

分别介绍了篮子期权和亚式期权这两种新型期权定价模型.使用Mellin变换法在Black-Scholes模型框架下研究了常值波动率及无风险利率情况下,求解和分析了一篮子期权的定价模型;以算术平均价格的平均价格型亚式看涨期权为例来建立亚式期权定价模型.这两种新型定价模型较之标准期权定价模型有较大优势,因而对它们的研究具有现实意义.