Defining the Impact of Non‐Native Species

Non‐native species cause changes in the ecosystems to which they are introduced. These changes, or some of them, are usually termed impacts; they can be manifold and potentially damaging to ecosystems and biodiversity. However, the impacts of most non‐native species are poorly understood, and a synthesis of available information is being hindered because authors often do not clearly define impact. We argue that explicitly defining the impact of non‐native species will promote progress toward a better understanding of the implications of changes to biodiversity and ecosystems caused by non‐native species; help disentangle which aspects of scientific debates about non‐native species are due to disparate definitions and which represent true scientific discord; and improve communication between scientists from different research disciplines and between scientists, managers, and policy makers. For these reasons and based on examples from the literature, we devised seven key questions that fall into 4 categories: directionality, classification and measurement, ecological or socio‐economic changes, and scale. These questions should help in formulating clear and practical definitions of impact to suit specific scientific, stakeholder, or legislative contexts. Definiendo el Impacto de las Especies No‐Nativas     

Effect of Planning for Connectivity on Linear Reserve Networks

Although the concept of connectivity is decades old, it remains poorly understood and defined, and some argue that habitat quality and area should take precedence in conservation planning instead. However, fragmented landscapes are often characterized by linear features that are inherently connected, such as streams and hedgerows. For these, both representation and connectivity targets may be met with little effect on the cost, area, or quality of the reserve network. We assessed how connectivity approaches affect planning outcomes for linear habitat networks by using the stock‐route network of Australia as a case study. With the objective of representing vegetation communities across the network at a minimal cost, we ran scenarios with a range of representation targets (10%, 30%, 50%, and 70%) and used 3 approaches to account for connectivity (boundary length modifier, Euclidean distance, and landscape‐value [LV]). We found that decisions regarding the target and connectivity approach used affected the spatial allocation of reserve systems. At targets ≥50%, networks designed with the Euclidean distance and LV approaches consisted of a greater number of small reserves. Hence, by maximizing both representation and connectivity, these networks compromised on larger contiguous areas. However, targets this high are rarely used in real‐world conservation planning. Approaches for incorporating connectivity into the planning of linear reserve networks that account for both the spatial arrangement of reserves and the characteristics of the intervening matrix highlight important sections that link the landscape and that may otherwise be overlooked. El Efecto de la Planeación para la Conectividad en Redes de Reservas Lineales     

Enrichment and Isolation of a Mixed Bacterial Culture for Complete Mineralization of Endosulfan

In the present study, we isolated three novel bacterial species, namely, Staphylococcus sp., Bacillus circulans–I, and Bacillus circulans–II, from contaminated soil collected from the premises of a pesticide manufacturing industry. Batch experiments were conducted using both mixed and pure cultures to assess their potential for the degradation of aqueous endosulfan in aerobic and facultative anaerobic condition. The influence of supplementary carbon (dextrose) source on endosulfan degradation was also examined. After four weeks of incubation, mixed bacterial culture was able to degrade 71.82 ± 0.2% and 76.04 ± 0.2% of endosulfan in aerobic and facultative anaerobic conditions, respectively, with an initial endosulfan concentration of 50 mg l^?1. Addition of dextrose to the system amplified the endosulfan degradation efficiency by 13.36 ± 0.6% in aerobic system and 12.33 ± 0.6% in facultative anaerobic system. Pure culture studies were carried out to quantify the degradation potential of these individual species. Among the three species, Staphylococcus sp. utilized more beta endosulfan compared to alpha endosulfan in facultative anaerobic system, whereas Bacillus circulans–I and Bacillus circulans–II utilized more alpha endosulfan compared to beta endosulfan in aerobic system. In any of these degradation studies no known intermediate metabolites of endosulfan were observed.     

Effects of Forest Fragmentation on Understory Hummingbirds in Amazonian Brazil

We sampled understory hummingbirds in Amazonian forest fragments from before isolation through nine years after isolation. We recorded 377 captures of eight species in five 1-ha fragments and four 10-ha fragments. The three species netted before isolation, Phaethornis superciliosus, Phaethornis bourcieri , and Thalurania furcata , were nearly equally abundant at that time. After isolation abundance of P. bourcieri and T. furcata did not change, but P. superciliosus became nearly twice as common. Five additional species that were netted only after isolation represented about 10% of the post-isolation sample. The species recorded only after isolation were forest species usually found above the levels of nets; fragments were not colonized by nonforest species. Use of fragments did not differ between 1- and 10-ha fragments. The landscape surrounding the fragments included active cattle pasture, abandoned pasture, and Cecropia -dominated second growth, but this variation had little effect on use of fragments by hummingbirds. The results suggest that these understory hummingbirds can persist in a matrix of fragments, secondary growth, and large forest patches. This response is much different than that of the insectivorous birds that dominate the understory bird community at the site, which are much more vulnerable to fragmentation.     

Deforestation in Brazilian Amazonia: History, Rates, and Consequences

Abstract:  Brazil's Amazon forest remained largely intact until the "modern" era of deforestation began with the inauguration of the Transamazon Highway in 1970. Amazonian deforestation rates have trended upward since 1991, with clearing proceeding at a variable but rapid pace. Although Amazonian forests are cut for various reasons, cattle ranching predominates. The large and medium-sized ranches account for about 70% of clearing activity. Profit from beef cattle is only one of the income sources that make deforestation profitable. Forest degradation results from logging, ground fires (facilitated by logging), and the effects of fragmentation and edge formation. Degradation contributes to forest loss. The impacts of deforestation include loss of biodiversity, reduced water cycling (and rainfall), and contributions to global warming. Strategies to slow deforestation include repression through licensing procedures, monitoring, and fines. The severity of penalties for deforestation needs to be sufficient to deter illegal clearing but not so great as to be unenforceable. Policy reform is also needed to address root causes of deforestation, including the role of clearing in establishing land claims.     

Climatic Change, Wildfire, and Conservation

Abstract:  Climatic variability is a dominant factor affecting large wildfires in the western United States, an observation supported by palaeoecological data on charcoal in lake sediments and reconstructions from fire-scarred trees. Although current fire management focuses on fuel reductions to bring fuel loadings back to their historical ranges, at the regional scale extreme fire weather is still the dominant influence on area burned and fire severity. Current forecasting tools are limited to short-term predictions of fire weather, but increased understanding of large-scale oceanic and atmospheric patterns in the Pacific Ocean (e.g., El Niño Southern Oscillation, Pacific Decadal Oscillation) may improve our ability to predict climatic variability at seasonal to annual leads. Associations between these quasi-periodic patterns and fire occurrence, though evident in some regions, have been difficult to establish in others. Increased temperature in the future will likely extend fire seasons throughout the western United States, with more fires occurring earlier and later than is currently typical, and will increase the total area burned in some regions. If climatic change increases the amplitude and duration of extreme fire weather, we can expect significant changes in the distribution and abundance of dominant plant species in some ecosystems, which would thus affect habitat of some sensitive plant and animal species. Some species that are sensitive to fire may decline, whereas the distribution and abundance of species favored by fire may be enhanced. The effects of climatic change will partially depend on the extent to which resource management modifies vegetation structure and fuels.     

重稀土元素钇对短程反硝化工艺的影响

研究重稀土元素钇（Y（III））对短程反硝化工艺的短期和长期影响.结果表明,1~50mg/L的Y（III）对亚硝酸盐的积累量无明显影响,60~100mg/L的Y（III）会影响硝酸盐的还原和亚硝酸盐的积累.1~10mg/L的Y（III）对细菌活性呈现促进作用,20~100mg/L的Y（III）对细菌活性呈现抑制作用.胞外吸附的Y（III）是抑制细菌活性的主要因子,线性拟合的相关性系数R²为0.957,半抑制浓度IC_50（吸附）为1.079mg/L（以湿重计）,对应水中Y（III）浓度为54.35mg/L.SEM显示,添加Y（III）会使细菌产生更多的胞外聚合物（EPS）将细菌包裹以抵抗Y（III）的毒性,EDS显示被包裹的细菌表面碳、氮元素含量大幅度降低,EPS影响了底物的传质.130d的长期实验表明,5mg/L的Y（III）会使反应器的反硝化性能逐渐消失,停止添加稀土后,反应器的亚硝酸盐积累功能也不能恢复.     

The Future of Scattered Trees in Agricultural Landscapes

Abstract: Mature trees scattered throughout agricultural landscapes are critical habitat for some biota and provide a range of ecosystem services. These trees are declining in intensively managed agricultural landscapes globally. We developed a simulation model to predict the rates at which these trees are declining, identified the key variables that can be manipulated to mitigate this decline, and compared alternative management proposals. We used the initial numbers of trees in the stand, the predicted ages of these trees, their rate of growth, the number of recruits established, the frequency of recruitment, and the rate of tree mortality to simulate the dynamics of scattered trees in agricultural landscapes. We applied this simulation model to case studies from Spain, United States, Australia, and Costa Rica. We predicted that mature trees would be lost from these landscapes in 90–180 years under current management. Existing management recommendations for these landscapes—which focus on increasing recruitment—would not reverse this trend. The loss of scattered mature trees was most sensitive to tree mortality, stand age, number of recruits, and frequency of recruitment. We predicted that perpetuating mature trees in agricultural landscapes at or above existing densities requires a strategy that keeps mortality among established trees below around 0.5% per year, recruits new trees at a rate that is higher than the number of existing trees, and recruits new trees at a frequency in years equivalent to around 15% of the maximum life expectancy of trees. Numbers of mature trees in landscapes represented by the case studies will decline before they increase, even if strategies of this type are implemented immediately. This decline will be greater if a management response is delayed.     

Designing Systematic Conservation Assessments that Promote Effective Implementation: Best Practice from South Africa

Abstract:  Systematic conservation assessment and conservation planning are two distinct fields of conservation science often confused as one and the same. Systematic conservation assessment is the technical, often computer-based, identification of priority areas for conservation. Conservation planning is composed of a systematic conservation assessment coupled with processes for development of an implementation strategy and stakeholder collaboration. The peer-reviewed conservation biology literature abounds with studies analyzing the performance of assessments (e.g., area-selection techniques). This information alone, however, can never deliver effective conservation action; it informs conservation planning. Examples of how to translate systematic assessment outputs into knowledge and then use them for "doing" conservation are rare. South Africa has received generous international and domestic funding for regional conservation planning since the mid-1990s. We reviewed eight South African conservation planning processes and identified key ingredients of best practice for undertaking systematic conservation assessments in a way that facilitates implementing conservation action. These key ingredients include the design of conservation planning processes, skills for conservation assessment teams, collaboration with stakeholders, and interpretation and mainstreaming of products (e.g., maps) for stakeholders. Social learning institutions are critical to the successful operationalization of assessments within broader conservation planning processes and should include not only conservation planners but also diverse interest groups, including rural landowners, politicians, and government employees.     

Gene Flow and Genetic Restoration: The Florida Panther as a Case Study

Populations of some endangered species have become so small that they have lost genetic variation and appear to have become fixed for deleterious genetic variants. To avoid extinction from this genetic deterioration individuals from related subspecies or populations may have to be introduced for genetic restoration i.e., elimination of deleterious variants and recovery to a normal level of genetic variation. I construct a general population genetics framework from which to evaluate the potential for genetic restoration, and I discuss its specific application to the Florida panther. The translocation of Texas cougars into the free-ranging Florida panther population has been recommended to genetically restore the Florida panther, a subspecies of Felis concolor that appears to have both a low level of genetic variation and low fitness. Specific recommendations recently given by a scientific panel are to introduce enough animals so that there is approximately 20% gene flow in the first generation of translocation and approximately 2–4% in the generations thereafter. I evaluated these recommendations in a theoretical population genetics framework and found that they should result in the removal of most detrimental genetic variation and an increase in the standing genetic variation without a high probability of loss of any adaptive Florida panther alleles. Unless the population of the free-ranging Florida panthers is very small, the planned translocation should result in genetic restoration of the Florida panther.