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Although the ecological impacts of biological invasions are well studied, comprehensive analyses of spending on invasive species management are lacking. Such analyses could inform both effective resource allocation and management planning. We evaluated long‐term invasive plant management expenditures and their potential geographic, economic, and ecological drivers for freshwater and terrestrial conservation areas in Florida, USA. Average expenditures for managing invaders were approximately US$45M annually, with over 90% of funding provided by the state. Our model showed that expenditures were best predicted by the prevalence of waterways and abundance of invaders, indicating that funding was allocated towards asset protection in highly invaded aquatic and terrestrial habitats. Higher spending was directly correlated with reduced area invaded for the costliest invader (Hydrilla verticillata, ~$10M/year), demonstrating management efficacy and constructive use of resources. Our study highlights that significant funding is required to manage plant invaders in Florida and that greater funding would likely limit the extent of invasions. Additional analyses of management cost‐effectiveness for Florida and other regions would benefit from consistent collection and reporting of high‐resolution management data. Given the exponential rate of spread of many invaders, additional and sustained management funding is needed for early detection and rapid, effective control of invasive species.

China's South to North Water Diversion (SNWD) project connects portions of the Yangtze River in the south to the Yellow River system in the north, overcoming biogeographic barriers to water movement. The diversion will supply potable water to over 110 million people and provide multiple other socioeconomic benefits. However, an inadvertent negative impact of this connection includes creation of conduits for species invasions. Alligator weed (Alternanthera philoxeroides), water hyacinth (Eichhornia crassipes), and water lettuce (Pistia stratiotes) are the only aquatic plant species on China's shortlists for special control. These species are mainly invasive in the Yangtze River basin. If these species are able to invade the SNWD and further spread via the SNWD, they have the potential to alter water supply, including water quantity and quality, as well as local ecology and agriculture, threatening the goals of the diversion. Understanding the full potential for these species to invade northern China is critical to early management decisions to avoid costly negative impacts. We used Maxent modeling to evaluate the probability that each of these species might become invasive in the receiving water regions. The models predict that all three species will be able to expand their ranges northward, with alligator weed and water hyacinth having the greatest potential for range expansion. These results suggest the need for prevention, monitoring, and management strategies for these species to reduce the risk and costs of impacts.

Background Schistosomiasis is a globally important water-borne zoonotic disease carried by parasitic schistosome species, which are obligately dependent on freshwater snails as intermediate hosts. In China, Oncomelania hupensis Gredler is the only endemic snail host of the schistosome species, Schistosoma japonicum. The current distribution of the snail along the Yangtze River basin has limited schistosomiasis in the region to five Chinese provinces along the middle and lower reaches. However, northward movement of snails is now possible via the South to North Water Diversion (SNWD), which transfers water from the Yangtze to northern China. Methods Data on the distribution of O. hupensis were collected from the Global Biodiversity Inventory Facility (http://www.gbif.org/) and published literature, and 19 bioclimatic variables from the WorldClim database (http://www.worldclim.org ) were used to describe the environmental characteristics of O. hupensis habitat. We obtained BCC_CSM1.1 data for the Representative Concentration Pathways (RCP) 4.5 scenario for 2050 and 2070 from WorldClim(http://www.worldclim.org/), and modeled the potential future distribution of O. hupensis using MaxEnt method. Findings Sections of the water-receiving provinces, Shandong and Henan, have suitable conditions for the snail, providing a conduit for disease movement into new regions. Snail control and schistosomiasis prevention work should focus on the southern part of Henan Province and on Nansi Lake in Shandong Province. Interpretation This work demonstrates the value of modeling for anticipating and preventing spread of schistosomiasis by targeting the regions where snail spread is most probable and focusing early detection and rapid response efforts to break the transmission link. Funding Statement: Partly supported by Improving project of Shandong Association of Science & Technology for Society, Shandong Science &Technology Program. DRG was supported by Environmental Defense Fund. Declaration of Interests: We declare no competing interests.

Risk assessment tools for non-native species can avert ecological and economic harm when they inform regulatory or voluntary management actions that seek to reduce the probability of introducing high-risk species. The Laurentian Great Lakes region contains many aquatic invasive plants, non-native species whose introduction causes economic or environmental harm or harm to human health. Additionally, new species continue to arrive, including through trade (e.g., aquarium, water garden). Currently, each Great Lakes jurisdiction manages a separate risk assessment program, leading to a regional situation with diverse assessment methods and large discrepancies in assessed and regulated species. Because the Great Lakes ecosystem crosses state and national borders, each jurisdiction will be best protected when all jurisdictions prevent the import of potentially harmful species. We have modified an existing risk assessment tool for use across the Great Lakes Basin to assess the invasion risks posed by aquatic plants. The tool comprises 38 questions, with points associated with each response that are summed to give a total score. We assessed all known established aquatic plant species in the Great Lakes (n=40) and found this score to be positively correlated with invasiveness, allowing thresholds to be identified that distinguish between invasive and non-invasive species with 84% to 90% accuracy. Assessing species proposed for introduction with this tool, and using these thresholds to determine acceptable risk, could reduce the number of future invasions. If widely adopted, this risk assessment tool would enable a common suite of species to be regulated and thus a more effective approach to reducing the risk of future invasions. Regional risk assessment approaches should reduce the threat of invasive species where environmental and climate conditions are relatively consistent across jurisdictional boundaries.

In her 1998 essay in Science (http://io.aibs.org/sci1), Jane Lubchenco boldly called for a new “Social Contract for Science,” one that would acknowledge the scope and scale of environmental problems and have “all scientists devote their energies and talents to the most pressing problems of the day in proportion to their importance.” We were entering a new millennium, and Lubchenco was worried that the scientific enterprise was unprepared to address the challenges related to climate change, pollution, health, and technology. Here we are, 20 years later, and our global challenges have only grown in complexity and urgency. Never before have we had such a clear understanding of our environmental crises and yet also been so far from delivering the investment in actionable research that Lubchenco called for. If the March for Science is any indication, researchers are ready to engage. But will universities — both leaders and the faculty who govern—acknowledge the need for reform?

Doria R. Gordon, S. Luke Flory, Deah Lieurance, Philip E. Hulme, Chris Buddenhagen, Barney Caton, Paul D. Champion, Theresa M. Culley, Curt Daehler, Franz Essl, Jeffrey E. Hill, Reuben P. Keller, Lisa Kohl, Anthony L. Koop, Sabrina Kumschick, David M. Lodge, Richard N. Mack, Laura A. Meyerson, Godshen R. Pallipparambil, F. Dane Panetta, Read Porter, Petr Pysek, Lauren D. Quinn, David M. Richardson, Daniel Simberloff, and Montserrat Vila*

Reintroduction of native species has become increasingly important in conservation worldwide for recovery of rare species and restoration purposes. However, few studies have reported the outcome of reintroduction efforts in plant species. Using data from the literature combined with a questionnaire survey, this paper analyses 249 plant species reintroductions worldwide by assessing the methods used and the results obtained from these reintroduction experiments. The objectives were: (1) to examine how successful plant species reintroductions have been so far in establishing or significantly augmenting viable, self-sustaining populations in nature; (2) to determine the conditions under which we might expect plant species reintroductions to be most successful; (3) to make the results of this survey available for future plant reintroduction trials. Results indicate that survival, flowering and fruiting rates of reintroduced plants are generally quite low (on average 52%, 19% and 16%, respectively). Furthermore, our results show a success rate decline in individual experiments with time. Survival rates reported in the literature are also much higher (78% on average) than those mentioned by survey participants (33% on average). We identified various parameters that positively influence plant reintroduction outcomes, e.g., working in protected sites, using seedlings, increasing the number of reintroduced individuals, mixing material from diverse populations, using transplants from stable source populations, site preparation or management effort and knowledge of the genetic variation of the target species. This study also revealed shortcomings of common experimental designs that greatly limit the interpretation of plant reintroduction studies: (1) insufficient monitoring following reintroduction (usually ceasing after 4 years); (2) inadequate documentation, which is especially acute for reintroductions that are regarded as failures; (3) lack of understanding of the underlying reasons for decline in existing plant populations; (4) overly optimistic evaluation of success based on short-term results; and (5) poorly defined success criteria for reintroduction projects. We therefore conclude that the value of plant reintroductions as a conservation tool could be improved by: (1) an increased focus on species biology; (2) using a higher number of transplants (preferring seedlings rather than seeds); (3) taking better account of seed production and recruitment when assessing the success of reintroductions; (4) a consistent long-term monitoring after reintroduction.

Twelve taxa under exploration as bioenergy crops in Florida and the U.S. were evaluated for potential invasiveness using the Australian Weed Risk Assessment system (WRA) modified for separate assessment at the state and national scales. When tested across a range of geographies, this system correctly identifies invaders 90%, and non-invaders 70% of the time, on average. Predictions for Florida were the same as for the U.S. Arundo donax, Eucalyptus camaldulensis, Eucalyptus grandis, Jatropha curcas, Leucaena leucocephala, Pennisetum purpureum, and Ricinus communis were found to have a high probability of becoming invasive, while Miscanthus × giganteus, Saccharum arundinaceum, Saccharum officinarum, and the sweet variety of Sorghum bicolor have a low probability of becoming invasive. Eucalyptus amplifolia requires further evaluation before a prediction is possible. These results are consistent with reports on other tests of these taxa. Given the economic and ecological impacts of invasive species, including the carbon expended for mechanical and chemical control efforts, cultivation of taxa likely to become invasive should be avoided.

Lightning- and human-ignited fires have shaped many of Florida's natural communities. Plant persistence in these habitats requires adaptation to survive high temperatures, ability to respond to aboveground tissue loss, or avoidance of these conditions through survival in unburned patches or in the soil seed bank. Limited distribution of many rare species in increasingly fragmented habitats and uncertainty of whether rare species tolerate, require, or persist through avoidance of fire hampers fire management when it is possible and threatens long-term viability of plants. We review up to 14 years of monitoring data for 18 rare plant species from 14 families occurring on sandhill, scrub, pine rockland, and mixed deciduous hardwood communities across Florida. For a number of variables measured, including density, frequency, flowering, and recruitment, 50% of the species showed significant positive responses to burning and 50% of the species showed a neutral or no response. None of the species were ...

Understanding the proximate causes of post-fire conifer mortality due to smoldering duff fires is essential to the restoration and management of coniferous forests throughout North America. To better understand duff fire-caused mortality, we investigated tree stress and radial growth following experimental fires in a long-unburned forest on deep sands in northern Florida, USA. We burned basal fuels surrounding 80 mature Pinus palustris Mill. in a randomized experiment comparing the effects of basal burning treatments on stem vascular meristems; surficial roots; root and stem combinations; and a non-smoldering control. We examined the effects of duration of lethal temperatures (>60 8C) on subsequent pine radial growth and root non-structural carbohydrates (starch and sugar). Duff and mineral soil temperatures in the experimental fires consistently exceeded 60 8C for over an hour following ignition, with lethal temperatures of shorter duration recorded 20 cm below the mineral soil surface. Duff heating was best explained by day-of-burn Oe horizon moisture (P = 0.01), although little variation was explained (R 2 = 0.24). Post-fire changes in latewood radial increment in the year following fires was related to duration of temperatures >60 8C 10 cm deep in the mineral soil (P = 0.07), but explained little variability in post-fire growth (R 2 = 0.17). In contrast, changes in non-structural carbohydrate content in coarse roots (2–5 mm diameter) 120 days following burning were more strongly correlated with the duration of lethal heating 5 cm below the mineral soil surface (P = 0.02; R 2 = 0.53). Results from this study implicate the role of mineral soil heating in the post-fire decline of

The magnitude of the invasive plant species problem necessitates prioritization of species for control, regulatory, and public-education programs. Many such priority lists exist but few have been developed according to specified procedures and criteria. We reviewed approaches to assessing the status of nonnative plant species currently occurring in natural areas (status assessments). We identify four generalized types of status assessments, which reflect a gradation from those that simply adopt existing lists from elsewhere (type 1), to those with relatively easy and rapid development and implementation (type 2), to those that are more time-consuming and costly but may be more robust in the face of challenges (types 3 and 4). These latter assessments explicitly have greater transparency, objectivity, and consistency than the other types. We use a matrix of assessment characteristics to distinguish the types of 17 example status assessments. We also review the factors related to assessment intent, scope, structure, content, and implementation that must be considered during the development of new status assessments so that the resulting tool and its products are appropriate for the user's purposes. These analyses should facilitate evaluation of different assessment methods and provide a basis for development of improved assessments. Identification of the relatively low percentage of nonnative plant species that are inflicting ecological and economic harm using well-understood and accepted assessment methods should facilitate a more comprehensive, collective approach to implementation of effective management efforts.

The economic, health, and environmental costs of invasive plant species suggest the need for screening systems to reduce the probability of importing new harmful invaders. We assessed 105 plant species introduced to the United States since 1995 using the Australian Weed Risk Assessment system and a secondary screen to evaluate the proportion of species that would have been prohibited from import were such a screening system implemented. These tools are likely to result in correct decisions to accept or reject species of unknown invasive potential over 80% of the time. The species tested spanned temperate and tropical locations of origin and represented all vascular plant life forms with the exception of aquatic plants. We had insufficient data to complete assessment of 4% of the species. None of the remaining 101 species were predicted to become invasive: 88% were predicted to be noninvasive and 12% required further evaluation. On average, we required 8 hours to assess each species. These results, in combination with the savings incurred when likely invaders are identified and prohibited prior to import, suggest that this screening system could be implemented to protect the economy and environment and would be unlikely to significantly preclude opportunities for the horticultural industry.

Screening tools that effectively predict which nonnative species are likely to become invasive are necessary because of the disproportionate ecological and economic costs associated with invaders. We tested the effectiveness of the Australian Weed Risk Assessment system (WRA) in distinguishing plant species that are major invaders, minor invaders, and noninvaders in Florida. The test included 158 annuals and perennials in six growth forms from 52 families in 27 orders. The WRA with a secondary screen met all hypothesized accuracy levels: it correctly rejected 92% of test species that have been documented to be invasive in Florida and correctly accepted 73% of the noninvaders. The incorrect rejection of noninvaders was 8% with the remaining 19% of noninvaders falling into the “evaluate further” outcome. Only 10% of the 158 species required further evaluation. Invaders of natural areas and agricultural systems were identified with equal accuracy. Receiver operating characteristic analysis demonstra...

In forests historically maintained by frequent fire, reintroducing fire after decades of exclusion often causes widespread overstory mortality. To better understand this phenomenon, we subjected 16 fire-excluded (ca. 40 years since fire) 10 ha longleaf pine ( Pinus palustris Mill.) stands to one of four replicated burning treatments based on volumetric duff moisture content (VDMC): wet (115% VDMC); moist (85% VDMC); dry (55% VDMC); and a no-burn control. During the first 2 years postfire, overstory pines in the dry burns suffered the greatest mortality (mean 20.5%); pine mortality in the wet and moist treatments did not differ from the control treatment. Duff reduction was greatest in the dry burns (mean 46.5%), with minimal reduction in the moist and wet burns (14.5% and 5%, respectively). Nested logistic regression using trees from all treatments revealed that the best predictors of individual pine mortality were duff consumption and crown scorch (P < 0.001; R2 = 0.34). Crown scorch was significant only in dry burns, whereas duff consumption was significant across all treatments. Duff consumption was related to moisture content in lower duff (Oa; R2 = 0.78, P < 0.001). Restoring fire to long-unburned forests will require development of burn prescriptions that include the effects of duff consumption, an often overlooked fire effect.

The Weed List Criteria Workshop consisted of four invited speakers and an animated discussion about the value of developing a standardized criteria system for developing lists of invasive plants. The presentations addressed the importance of having lists and criteria that are sufficiently robust to withstand legal challenges, the sophistication of a national prioritization system, some alternative strategies to the use of “one-size-fits-all” invasive plant lists, and the variety of lists that are already in use. Participants agreed that a standardized criteria system might need a modular format (e.g., agriculture or natural areas modules) with options for different thresholds for some criteria (e.g., rigor of documentation) to satisfy diverse listing objectives. Many participants expressed interest in future participation in this endeavor. Additional index words: List standardization, status assessment, weed lists.

The moth Cactoblastis cactorum (Berg), the poster child of weed biological control in Australia, has recently invaded the United States and threatens native cacti. Concern is greatest for the endangered semaphore cactus, Opuntia corallicola, of which only two known populations exist in the wild. We made three separate outplantings of O. corallicola, designed to bolster the number of extant cacti and to test the effectiveness of three different treatments to protect the cacti from Cactoblastis. In one outplanting, we tested the associational susceptibility hypothesis and found that cacti planted more than 20 m away from the common prickly pear cactus, Opuntia stricta, which act as a reservoir of Cactoblastis, were just as frequently attacked and killed by Cactoblastis as cacti planted within 5 m. In addition, Cactoblastis attack was greater in the shade than in the sun. In the second outplanting, we minimized the attack from Cactoblastis by using protective cages planted at least 500 m from O. stricta in areas not inhabited by cacti. Cages attracted the attention of local animals, which destroyed the cages and trampled the cacti inside to death. Crown rot caused high mortality in this outplanting. In the third outplanting, again conducted at least 500 m away from O. stricta, fertilization did not reduce crown rot mortality. We suggest that increasing populations of O. corallicola in Florida, by means of outplantings, will remain a challenge because of death from Cactoblastis when planted in areas where cacti normally grow and because of death from crown rot in areas where they do not. Because Cactoblastis is moving rapidly northward and westward and has already reached Charleston, South Carolina, rare cacti in the rest of the U.S. Southeast may be in danger. Eventually, many cactus species in the U.S. South, Southwest, and Mexico will likely be threatened by this moth.