Limited Conservation Funds Research Articles

Species and ecological communities as management surrogates for threatened biodiversity

In the face of the ongoing biodiversity crisis and limited conservation funding, surrogate approaches have become a valuable tool to represent biodiversity. Management surrogates are those that indirectly benefit an ecological system or species by representing the management requirements of co-occurring biodiversity. Recent findings highlight the cost-effective potential of surrogate species in managing threatened species, however, evaluating higher levels of biodiversity as management surrogates remains unexplored. Here, we sought to maximize conservation outcomes for threatened species and threatened ecological communities (TECs) by prioritizing management based on overlapping distributions, threats, and costs. We describe a prioritization framework for identifying TECs that could serve as cost-effective surrogates, and compare it with prioritizing threatened species only or both species and TECs. We show that when the objective is to maximize benefits for threatened species, a community approach performs poorly due to limited geographic overlap and high costs, while prioritizing species returned 7.5 times more benefits delivered to species under the same budget. Yet, if the objective is to maximize benefits across species and TECs simultaneously, a combined approach including both as surrogates delivers the greatest benefit for the same costs as a species-only approach. Range sizes and taxonomic groups significantly influenced the priority list, with threatened invertebrates and TECs of smaller ranges more likely to be selected as surrogates. Overall, this study emphasizes the importance of incorporating accurate data on factors such as threats and costs for identifying effective management surrogates, and highlights the potential benefits of prioritizing across multiple biodiversity features.

Total response models as a conceptual management framework for conserving vulnerable secondary prey

AbstractMany of the world's native fauna suffer unsustainable losses from invasive mammalian predators. Conservation managers control predators on the premise that if large numbers are removed, prey will respond. This is sometimes true, but not always. Empirical relationships between predator densities and responses of vulnerable prey in Oceania often show little or no response across a broad range of predator reductions, with positive responses only at low threshold predator densities. Even then, some prey populations fail to respond. More research is required to identify predator thresholds across a range of prey taxa. This uncertainty of outcomes, coupled with the considerable cost of mammalian pest control, risks little or no return from limited conservation funds. A unifying theory is required to help understand why conservation outcomes from predator control are so variable despite the best efforts of conservation managers, and to expedite the right kind of management for a given prey species. We argue that a modern synthesis of numerical and functional response theory, in the form of total response models, provides such a theory. Stochastic consumer‐resource models are recommended for dynamic systems, but they are difficult to parameterize. Total response models, on the other hand, present a simple conceptual framework that managers can use as a heuristic to understand predator–prey systems, help explain some of the variability in predator control outcomes and stimulate thinking about other management options that can be integrated with predator control to improve conservation outcomes. Five rules of thumb are suggested to assist conservation managers.

Tracking the global application of conservation translocation and social attraction to reverse seabird declines

The global loss of biodiversity has inspired actions to restore nature across the planet. Translocation and social attraction actions deliberately move or lure a target species to a restoration site to reintroduce or augment populations and enhance biodiversity and ecosystem resilience. Given limited conservation funding and rapidly accelerating extinction trajectories, tracking progress of these interventions can inform best practices and advance management outcomes. Seabirds are globally threatened and commonly targeted for translocation and social attraction ("active seabird restoration"), yet no framework exists for tracking these efforts nor informing best practices. This study addresses this gap for conservation decision makers responsible for seabirds and coastal management. We systematically reviewed active seabird restoration projects worldwide and collated results into a publicly accessible Seabird Restoration Database. We describe global restoration trends, apply a systematic process to measure success rates and response times since implementation, and examine global factors influencing outcomes. The database contains 851 active restoration events in 551 locations targeting 138 seabird species; 16% of events targeted globally threatened taxa. Visitation occurred in 80% of events and breeding occurred in 76%, on average 2 y after implementation began (SD = 3.2 y). Outcomes varied by taxonomy, with the highest and quickest breeding response rates for Charadriiformes (terns, gulls, and auks), primarily with social attraction. Given delayed and variable response times to active restoration, 5 y is appropriate before evaluating outcomes. The database and results serve as a model for tracking and evaluating restoration outcomes, and is applicable to measuring conservation interventions for additional threatened taxa.

Prioritizing Irrigation‐System Upgrades to Maximize Improvements to Agricultural Drain‐Network Water Quality: A Graph‐Theoretic Approach

AbstractWe develop and demonstrate an approach to optimally prioritize fields for irrigation‐system upgrades to improve agricultural‐drain discharge water quality. The approach accounts for the attenuation of pollutants transported along complex drain networks from fields to drain‐network outlets. The approach produces a Pareto‐optimal cost curve of irrigation‐system upgrade combinations that compromise between maximizing the reduction of drain‐outlet loads and minimizing upgrade implementation costs. The approach utilizes a graph‐theoretic data structure to organize drain‐network data, route drain‐network flow paths, and formulate objectives and constraints for multi‐objective optimization. Due to the linearity of the objective functions and constraints, Pareto‐optimal solutions are obtained along the cost curve by prioritizing fields by decreasing load‐reduction/cost ratio (pollutant load‐reduction per cost). Multi‐objective optimization will identify additional Pareto‐optimal solutions along the cost curve providing additional compromises. The approach allows for a computationally efficient prioritization, providing a level of complexity that is able to incorporate commonly available data. The cost curve is highly sensitive to the pollutant attenuation coefficient, with higher attenuation coefficients resulting in low sensitivity of load reduction to cost. While the focus of this work is on irrigation‐system upgrades, there are other conservation actions and/or land‐use change scenarios that this method could also prioritize. Analyses of this nature could prove valuable in improving the allocation of limited conservation funding and/or developing cost‐effective water quality trading programs. We demonstrate the approach on a collection of drain networks around Grand View, Idaho, USA with the objective to reduce total phosphorus loads to the Snake River.

Upgrading protected areas can improve or reverse the decline in conservation effectiveness: Evidence from the Tibetan Plateau, China

Protected areas (PAs) are considered essential for maintaining biodiversity. Several governments would like to strengthen the management levels of their PAs (as shorthand for a hierarchy in PA administrative governance) to consolidate their conservation effectiveness. This upgrade (e.g., from provincial- to national-level PAs) means stricter protection and increased funds for PA management. However, confirming whether such an upgrade can produce the expected positive outcomes is key given limited conservation funds. Here, we used the Propensity Score Matching (PSM) method to quantify the impacts of upgrading PAs (i.e., from provincial to national) on vegetation growth on the Tibetan Plateau (TP). We found that the impacts of PA's upgrading can be divided into two impact types: 1) curbed or reversed declines in conservation effectiveness and 2) rapidly increased conservation effectiveness before the upgrade. These results indicate that the PA's upgrading process (including the pre-upgrade operations) can improve PA effectiveness. Nevertheless, the gains did not always occur after the official upgrade. This study demonstrated that in comparison to other PAs, those with more resources or stronger management policies were more effective.

An investment strategy to address biodiversity loss from agricultural expansion

The landmark 2019 Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment cited land-use change as the primary driver of biodiversity loss. The 2016 peace agreement in Colombia has led to increasing agricultural expansion into biodiversity-rich forests. We have focused on the case of Colombia to demonstrate an approach to maximize the biodiversity benefits from limited conservation funding while ensuring that landowners maintain economic returns equivalent to agriculture. We applied a quantitative model that relates conservation investment to national biodiversity outcomes. Then we identified six regions with high potential return on investment by spatially modelling the risk of forest conversion and the expected impact of conservation actions. Our results suggest that agricultural expansion, left unchecked, would increase national biodiversity loss by 38–52% by 2033, and that doubling investment is necessary to counteract this loss. Our approach can be broadly used to target investment to weigh development and biodiversity goals. We demonstrate the approach in Colombia with its accelerated social and environmental changes and show how the efficiency of conservation options can be improved by considering opportunity cost of conservation to communities whose livelihoods depend on agriculture. This approach can be applied to other contexts to examine development and policy priorities to estimate financial needs for achieving biodiversity goals.

Bound within boundaries: Do protected areas cover movement corridors of their most mobile, protected species?

Abstract Conserving and managing large portions of land to connect wildlife reserves is an increasingly used strategy to maintain and restore connectivity among wildlife populations. Boundaries of such conservation areas are often determined based on expert opinion and socio‐political constraints, yet the extent to which they match species' movement corridors is rarely examined. This is mainly due to a lack of data, particularly on wide‐ranging movement behaviour such as dispersal. Nevertheless, empirically assessing the adequacy of protected areas is key for the implementation of targeted management actions and efficient use of limited conservation funds. Between 2011 and 2019, we collected high‐resolution GPS data on 16 dispersing African wild dog Lycaon pictus coalitions from a free‐ranging population in the Kavango–Zambezi Transfrontier Conservation Area (KAZA‐TFCA). Spanning five countries and 520,000 km2, the KAZA‐TFCA is the world's largest transboundary conservation area and a prime example for international conservation efforts. We used integrated step selection analysis to estimate habitat selection of dispersers and to create a permeability surface for the KAZA‐TFCA. We compared landscape permeability across different regions within the KAZA‐TFCA as well as outside its boundaries. Lastly, we calculated least‐cost paths and corridors to verify that major movement routes were adequately encompassed within the KAZA‐TFCA. Permeability within the boundaries of the KAZA‐TFCA was more than double compared to areas outside it. Furthermore, we observed a fivefold permeability difference among the five KAZA‐TFCA countries. We also showed that major movement corridors of wild dogs ran within the KAZA‐TFCA, although some minor routes remained formally unprotected. Differences in permeability were mainly related to different degrees of human activities across regions, and to the presence or absence of rivers, swamps and open water. The relationship between permeability and other landscape features was less pronounced. Synthesis and applications. In this study, we showed how pertinent dispersal data of a highly mobile species can be used to empirically evaluate the adequacy of already existing or planned protected areas. Furthermore, we observed regional differences in landscape permeability that highlight the need for a coordinated effort towards maintaining or restoring connectivity, especially where transboundary dispersal occurs.

Conservation Priorities Analysis of Chinese Indigenous Pig Breeds in the Taihu Lake Region.

Most indigenous pig resources are known to originate from China. Thus, establishing conservation priorities for these local breeds is very essential, especially in the case of limited conservation funds. Therefore, in this study, we analyzed 445 individuals belonging to six indigenous breeds from the Taihu Lake Region, using a total of 131,300 SNPs. In order to determine the long-term guidelines for the management of these breeds, we analyzed the level of diversity in the metapopulation following a partition of diversity within and between breed subpopulations, using both measures of genic and allelic diversity. From the study, we found that the middle Meishan (MMS) pig population contributes the most (22%) to the total gene diversity while the Jiaxing black (JX) pig population contributes the most (27%) to the gene diversity between subpopulations. Most importantly, when we consider one breed is removed from the meta-population, the first two breeds prioritized should be JX pig breed and Fengjing pig breed followed by small Meishan (SMS), Mizhu (MI), and Erhualian (EH) if we pay more attention to the gene diversity between subpopulations. However, if the priority focus is on the total gene diversity, then the first breed to be prioritized would be the Shawutou (SW) pig breed followed by JX, MI, EH, and Fengjing (FJ). Furthermore, we noted that if conservation priority is to be based on the allelic diversity between subpopulations, then the MI breed should be the most prioritized breed followed by SW, Erhuanlian, and MMS. Summarily, our data show that different breeds have different contributions to the gene and allelic diversity within subpopulations as well as between subpopulations. Our study provides a basis for setting conservation priorities for indigenous pig breeds with a focus on different priority criteria.

Mitigation translocation as a management tool.

Mitigation translocation is a subgroup of conservation translocation, categorized by a crisis-responsive time frame and the immediate goal of relocating individuals threatened with death. However, the relative successes of conservation translocations with longer time frames and broader metapopulation- and ecosystem-level considerations have been used to justify the continued implementation of mitigation translocations without adequate post hoc monitoring to confirm their effectiveness as a conservation tool. Mitigation translocations now outnumber other conservation translocations, and understanding the effectiveness of mitigation translocations is critical given limited global conservation funding especially if the mitigation translocations undermine biodiversity conservation by failing to save individuals. We assessed the effectiveness of mitigation translocations by conducting a quantitative review of the global literature. A total of 59 mitigation translocations were reviewed for their adherence to the adaptive scientific approach expected of other conservation translocations and for the testing of management options to continue improving techniques for the future. We found that mitigation translocations have not achieved their potential as an effective applied science. Most translocations focused predominantly on population establishment- and persistence-level questions, as is often seen in translocations more broadly, and less on metapopulation and ecosystem outcomes. Questions regarding the long-term impacts to the recipient ecosystem (12% of articles) and the carrying capacity of translocation sites (24% of articles) were addressed least often, despite these factors being more likely to influence ultimate success. Less than half (47%) of studies included comparison of different management techniques to facilitate practitioners selecting the most effective management actions for the future. To align mitigation translocations with the relative success of other conservation translocations, it is critical that future mitigation translocations conform to an established experimental approach to improve their effectiveness. Effective mitigation translocations will require significantly greater investment of time, expertise, and resources in the future.

A case study of improved cook stoves in primate conservation from Democratic Republic of Congo.

Human communities living near nonhuman primate habitats often depend on wood from forests for their energy needs. Improving the efficiency of local cook stoves is a potential "win-win" solution that is commonly promoted to protect forests and improve human health and development. Despite the popularity of improved stove projects in primate conservation, few outcomes have been formally published. As a result, it is currently unclear whether this approach is a wise investment of limited conservation funds. This paper describes a pilot study conducted by the Gorilla Rehabilitation and Conservation Education Center to evaluate the potential for using improved stoves for the conservation of an important habitat for Grauer's gorillas and chimpanzees in eastern Democratic Republic of Congo. Community surveys and observations of human forest use revealed a heavy local reliance on forest-derived wood. Wood was the main source of fuel used in households, the most highly valued forest resource, and the primary resource extracted during forest observations. It was primarily collected by women and children. The use of traditional, inefficient three-stone hearths for cooking was also widespread. A 2-year campaign using a community-based social marketing approach resulted in an increase in improved stove installations from 18% to 78% of households in one village. After stove adoption, weekly household wood consumption was reduced by half. Campaign elements that showed promise include promotion using women's networks and intensive follow-up assessment and support. We conclude that, if scaled up, improved stoves may be a useful strategy for reducing encroachment into our target protected area but that successful implementation will require a significant long-term commitment with evaluation and oversight. It is recommended that before investing in improved stoves, primate conservation projects take long-term and evaluation requirements into consideration.

To Achieve Big Wins for Terrestrial Conservation, Prioritize Protection of Ecoregions Closest to Meeting Targets

Most of the terrestrial world is experiencing high rates of land conversion despite growth of the global protected area (PA) network. There is a need to assess whether the current global protection targets are achievable across all major ecosystem types and to identify those that need urgent protection. Using recent rates of habitat conversion and protection and the latest terrestrial ecoregion map, we show that if the same approach to PA establishment that has been undertaken over the past three decades continues, 558 of 748 ecoregions (ca. 75%) will not meet an aspirational 30% area protection target by 2030. A simple yet strategic acquisition plan that considers realistic futures around habitat loss and PA expansion could more than double the number of ecoregions adequately protected by 2030 given current funding constraints. These results highlight the importance of including explicit ecoregional representation targets within any new post-2020 global PA target.

Weighing the benefits of expanding protected areas versus managing existing ones

Protected areas are a fundamental mechanism for conserving global biodiversity. Given limited conservation funds and shortfalls in funding for existing protected area management needs, a critical question is: should countries and states spend new funds on purchasing more land or managing existing protected areas to an acceptable standard? We used a non-spatial dynamic landscape model to compare the relative importance of expansion of protected areas versus improved protected area management in diverse contexts. We provide guidance on how to allocate funding across these two actions, and the order in which these actions should be prioritized. We discover that, in contrast with spending patterns, which focus on expansion rather than management, management is often the better first investment. The relative priority of expansion and management is determined by observable factors: the relative costs of the two actions and rates of degradation in protected and unprotected areas. Importantly, regardless of these factors, the final recommended action is always to split the budget across expansion and management such that there is adequate money for management. This highlights that, while our existing protected areas are an important asset, increased investment in management is essential to maximize their potential to protect biodiversity.

The application of environmental DNA in the monitoring of the Yangtze finless porpoise, Neophocaena phocaenoides asaeorientalis

PDF HTML阅读 XML下载 导出引用 引用提醒 环境DNA在长江江豚监测中的应用 DOI: 作者: 作者单位: 1. 南京农业大学无锡渔业学院, 江苏 无锡 214128;2. 中国水产科学研究院淡水渔业研究中心, 江苏 无锡 214128 作者简介: 吴昀晟(1992-),男,硕士研究生.E-mail:wysh6666@126.com 通讯作者: 中图分类号: S931 基金项目: 江苏省长江江豚繁育项目（苏财农2016-36号）；中国水产科学研究院基本科研业务费项目（2017HY-XKQ0201）；修复向家坝库区渔业资源及保护长江珍稀特有物种合作项目（F02西江保护区江豚迁入及驯养）. The application of environmental DNA in the monitoring of the Yangtze finless porpoise, Neophocaena phocaenoides asaeorientalis Author: Affiliation: 1. Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214128, China;2. Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214128, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了从水体环境中提取到高质量的eDNA环境DNA（environmental DNA，eDNA），应用于长江中长江江豚（）的分布调查，本研究比较了滤膜孔径和水样保存方式对eDNA获取的影响，同时对比了eDNA技术与传统调查法对长江江豚的检测结果。结果显示水样抽滤时间与滤膜孔径大小呈负相关关系，且都可以检出目标生物；水样采集后需在6 h内完成抽滤处理，或在冷藏条件下短期保存48 h；长江流域江苏段中观测到长江江豚出现的8个检测点均检测出长江江豚eDNA，而在10个未观测到长江江豚的水域中有3个检测出其eDNA。研究结果表明，相比传统目视监测方法，eDNA技术在长江江豚监测中不仅具有较高的准确性，还具有更高的灵敏性，可作为长江江豚种群调查的有效辅助检测工具。 Abstract:The Yangtze finless porpoise, (YFP) is the flagship of aquatic protection species in the Yangtze River in China. The number of Yangtze finless porpoises is continuously decreasing because their living conditions are affected by human factors. Determining the distribution of the finless porpoises is necessary to protect them; however, surveys all along the Yangtze River are time-consuming and expensive. Environmental DNA (eDNA) technology used for the detection of organisms is economical, efficient, accurate, sensitive, and non-invasive and can narrow the scope of investigation, which allows limited conservation funds to be used more efficiently. It has already been applied to detect and estimate the distribution of endangered or invasive aquatic species. Environmental DNA technology often deals with a small amount of degraded and short DNA fragments, which implies that maximizing the eDNA yield is required to improve the accurate detection of the target organism from turbid stream systems. In this study, we compared the effects of four different pore-sized filters (10 μm, 5 μm, 1 μm, 0.45 μm) on the filtration time of eDNA during its extraction from stream water. Also, we compared the eDNA yield from water samples stored under two different conditions (room temperature 20℃, refrigerated 4℃) over a 14 day period. Results showed that the target eDNA was detected from the four different pore-sized filters; however, the filtration time was negatively correlated with the pore sizes of the filters. Considering the filtration time, the combination of a large pore-sized filter (5 μm) and a high volume of water (1 L) from the samples is a good choice to extract eDNA from the Yangtze River. Different storage methods and times significantly affected the eDNA yield. Thus, our results also support the recommendation that the water samples from the Yangtze River should be filtered within 6 hours of collection at room temperature or be stored at 4℃ for a short period of time (i.e., 48 hours). The eDNA concentration in the water samples dropped below the threshold for detection when they were stored at room temperature for 10 days or at 4℃ for 14 days; thus, the eDNA in the water samples is not suited for long-term preservation. Compared with traditional field investigations, the eDNA survey exhibited a 100% detection rate from the Yangtze river in the Jiangsu Province where the finless porpoise has emerged. Three positive results were also detected from 10 survey points where the finless porpoise has not yet been observed. The fitted curve between the number of finless porpoises and the eDNA yield was built to estimate the biomass of the porpoises within an area of water. Although eDNA production and degradation is affected by many environmental factors such as temperature, pH, and microbial communities, the technology was still more sensitive than traditional field investigations for the detection of the Yangtze finless porpoise in the Yangtze River. 参考文献 相似文献 引证文献

Assessment of repeat‐visit surveys as a viable method for estimating brood abundance at the 10.4‐km2 scale

ABSTRACTRegional estimates of duck brood abundance could help conservation managers assess landscape productivity and thereby improve spatially explicit allocation of limited conservation funds in the Prairie Pothole Region. We assessed the utility of repeat‐visit brood counts from 2012 to 2013 surveys in the Prairie Pothole Region (ND, SD, and MT, USA) and hierarchical N‐mixture models for providing estimates of abundance at a 10.4‐km2 scale. Models provided reliable estimates of brood abundance and underscored the importance of small wetlands and landscape characteristics to some dabbling duck broods in the Prairie Pothole Region. © 2018 The Wildlife Society.

Bigger or better: The relative benefits of protected area network expansion and enforcement for the conservation of an exploited species

AbstractThe global portfolio of protected areas is growing rapidly, despite widely recognized shortfalls in management effectiveness. Pressure to meet area‐coverage and management effectiveness objectives makes it essential to determine how limited conservation funds should be allocated between expanding protected area networks and better enforcing existing reserves. We formally explore this question for the particular case of an exploited species in a partially protected system, using a general model linking protection, enforcement and legal/illegal resource extraction. We show that, on average, funds should be disproportionately invested in enforcement rather than expansion. Further, expansion alone, without additional enforcement, can actually reduce conservation outcomes. To help guide future decisions, we calculate the optimal allocation of resources between these two actions given any current level of enforcement and protected area coverage. In most cases, simultaneously investing in expansion and enforcement is the optimal decision. However, in places with low enforcement and high protection, protected area contraction, or strategically concentrating enforcement effort, produces the greatest benefits.

Effectiveness of seed sowing techniques for sloped restoration sites

AbstractPractitioners are challenged with choosing among many potentially effective methods for sowing seed in ecological restoration projects to achieve sufficient native plant establishment. We tested the effectiveness of seed sowing techniques on moderate and steep slopes in a Mediterranean climate by measuring native seedling density immediately following germination, as well as plant density, recruitment success, and soil movement through the second growing season. We calculated cost effectiveness of different methods as the native plant density per dollar spent sowing seed. While all sowing techniques resulted in significant native establishment compared with unseeded controls, hydro seeding on moderate slopes was the most cost effective (native seedlings established per dollar spent). Although all steep‐sloped seeding techniques resulted in high densities of native species, all methods also resulted in significant soil loss. Shrubs preferred hand seeding followed by jute netting on steep slopes, while forbs reached greatest densities with hydro seeding on moderate slopes. Seedlings of species with heavy seeds were present in greater densities than species with lighter seeds in imprint sowing treatments. The “best” seed sowing technique varied depending on slope and metric of success (native density, species richness, shrub density, or forb density). Different combinations of slope, technique, and success metric resulted in significantly different project costs, which implies opportunities for savings given careful decision‐making relative to mitigation needs on heterogeneous landscapes. Evaluations of techniques for restoring slopes are limited, yet critical for expanding the area capable of being restored and the application of limited conservation funding.

Optimizing expenditures for agricultural land conservation: Spatially-explicit estimation of benefits, budgets, costs and targets

This paper presents an empirical analysis of the optimal use of financial resources for agricultural land conservation in the Alberta Capital Region, Canada. All elements of the analysis are spatially explicit, including estimation of benefits and budgets from a choice experiment with Capital Region residents, assessed farmland value and list price data on conservation costs, and priority targets for conservation. The performance and efficiency of four targeting criteria are evaluated and compared for alternative budgets that are derived from the benefit study, applied to two sets of data on costs. The results show considerable interest in farmland conservation in the Alberta Capital Region: we estimate that a one-time increase in property taxes or rent that would generate $CAD 17.6 million would be acceptable to 75% of the population. Willingness to pay for conservation was highest for land used for commercial vegetable production, located near to primary highways and outside of city limits. However, the difference in willingness to pay to conserve such land generally does not offset the higher costs of that type of land, and efficient use of limited conservation funds would result in the targeting of lower-cost grazing lands located further from the main population centres. As expected, the branch-and-bound optimization (OPT) and benefit-cost ratio targeting (BCRT) provide more efficient use of conservation funds than either benefit targeting (BT) or cost targeting (CT).

Co-occurring nonnative woody shrubs have additive and non-additive soil legacies.

To maximize limited conservation funds and prioritize management projects that are likely to succeed, accurate assessment of invasive nonnative species impacts is essential. A common challenge to prioritization is a limited knowledge of the difference between the impacts of a single nonnative species compared to the impacts of nonnative species when they co-occur, and in particular predicting when impacts of co-occurring nonnative species will be non-additive. Understanding non-additivity is important for management decisions because the management of only one co-occurring invader will not necessarily lead to a predictable reduction in the impact or growth of the other nonnative plant. Nonnative plants are frequently associated with changes in soil biotic and abiotic characteristics, which lead to plant-soil interactions that influence the performance of other species grown in those soils. Whether co-occurring nonnative plants alter soil properties additively or non-additively relative to their effects on soils when they grow in monoculture is rarely addressed. We use a greenhouse plant-soil feedback experiment to test for non-additive soil impacts of two common invasive nonnative woody shrubs, Lonicera maackii and Ligustrum sinense, in deciduous forests of the southeastern United States. We measured the performance of each nonnative shrub, a native herbaceous community, and a nonnative woody vine in soils conditioned by each shrub singly or together in polyculture. Soils conditioned by both nonnative shrubs had non-additive impacts on native and nonnative performance. Root mass of the native herbaceous community was 1.5timeslower and the root mass of the nonnative L.sinense was 1.8timeshigher in soils conditioned by both L.maackii and L.sinense than expected based upon growth in soils conditioned by either shrub singly. This result indicates that when these two nonnative shrubs co-occur, their influence on soils disproportionally favors persistence of the nonnative L.sinense relative to this native herbaceous community, and could provide an explanation of why native species abundance is frequently depressed in these communities. Additionally, the difference between native and nonnative performance demonstrates that invasive impact studies focusing on the impact only of single species can be insufficient for determining the impact of co-occurring invasive plant species.

Using Public Preferences to Weight Species Prioritization Criteria in Conservation Decision Making: A Case Study to Explore Potential Strengths and Weaknesses

ABSTRACTThe conservation of biodiversity depends on the implementation of policy with limited financial resources. Due to this shortage of resources, conservation activities must be prioritized so that scarce funds are used rationally to prevent long-term biodiversity loss. To assure funding continuity, since it is the public that pays a significant part of conservation costs, it is imperative that managers and policymakers apply limited conservation funds in a way that makes people feel that their concerns about biodiversity loss are addressed. Here we argue for public preferences to be incorporated in species conservation decision making through criteria weighting. Public preferences were analyzed in two different contexts (abstract vs. concrete) to understand how stable public preferences are across different elicitation procedures. Our results show some resilience in criteria ranking, with functional importance being considered as the top criterion across different ways of questioning.

Using counterfactuals to evaluate the cost-effectiveness of controlling biological invasions.

Prioritizing limited conservation funds for controlling biological invasions requires accurate estimates of the effectiveness of interventions to remove invasive species and their cost-effectiveness (cost per unit area or individual). Despite billions of dollars spent controlling biological invasions worldwide, it is unclear whether those efforts are effective, and cost-effective. The paucity of evidence results from the difficulty in measuring the effect of invasive species removal: a researcher must estimate the difference in outcomes (e.g. invasive species cover) between where the removal program intervened and what might have been observed if the program had not intervened. In the program evaluation literature, this is called a counterfactual analysis, which formally compares what actually happened and what would have happened in the absence of an intervention. When program implementation is not randomized, estimating counterfactual outcomes is especially difficult. We show how a thorough understanding of program implementation, combined with a matching empirical design can improve the way counterfactual outcomes are estimated in nonexperimental contexts. As a practical demonstration, we estimated the cost-effectiveness of South Africa's Working for Water program, arguably the world's most ambitious invasive species control program, in removing invasive alien trees from different land use types, across a large area in the Cape Floristic Region. We estimated that the proportion of the treatment area covered by invasive trees would have been 49% higher (5.5% instead of 2.7% of the grid cells occupied) had the program not intervened. Our estimates of cost per hectare to remove invasive species, however, are three to five times higher than the predictions made when the program was initiated. Had there been no control (counter-factual), invasive trees would have spread on untransformed land, but not on land parcels containing plantations or land transformed by agriculture or human settlements. This implies that the program might have prevented a larger area from being invaded if it had focused all of its clearing effort on untransformed land. Our results show that, with appropriate empirical designs, it is possible to better evaluate the impacts of invasive species removal and therefore to learn from past experiences.