Natural Resources Science Faculty Publications Copyright (c) 2013 University of Rhode Island All rights reserved. http://digitalcommons.uri.edu/nrs_facpubs Recent documents in Natural Resources Science Faculty Publications en-us Sun, 05 May 2013 01:40:25 PDT 3600 Impact of Ectoparasites on the Demography of a Small Reef Fish http://digitalcommons.uri.edu/nrs_facpubs/24 http://digitalcommons.uri.edu/nrs_facpubs/24 Fri, 03 May 2013 08:09:52 PDT In marine systems, empirical studies demonstrating effects of macroparasites on host population dynamics are relatively few. We tested the effects of a copepod macroparasite infecting the gills of a small coral reef fish, the bridled goby Coryphopterus glaucofraenum. Fish that were naturally infected and uninfected were tagged as individuals and tracked in the field for 5 mo. Parasitism was associated with an increase in gill ventilation rate, and a reduction in feeding. More importantly, parasitized fish showed significantly reduced growth (by 66%) and gonad mass (by 68%) compared to uninfected fish, and parasitism increased instantaneous mortality by a factor of 1.8. Since the prevalence of infection was higher in areas of high goby density, parasiteinduced mortality is a possible cause of host density dependence. These results imply a major effect of parasitism on host population dynamics and suggest that parasitism warrants closer attention by marine ecologists.

]]> Rachel J. Finley et al. Parasitism and a Shortage of Refuges Jointly Mediate the Strength of Density Dependence in a Reef Fish http://digitalcommons.uri.edu/nrs_facpubs/23 http://digitalcommons.uri.edu/nrs_facpubs/23 Wed, 01 May 2013 10:02:15 PDT Various predator-prey, host-pathogen, and competitive interactions can combine to cause density dependence in population growth. Despite this possibility, most empirical tests for density-dependent interactions have focused on single mechanisms. Here we tested the hypothesis that two mechanisms of density dependence, parasitism and a shortage of refuges, jointly influence the strength of density-dependent mortality. We used mark recapture analysis to estimate mortality of the host species, the bridled goby {Coryphopterus glaucofraenum). Sixty-three marked gobies were infected with a copepod gill parasite {Pharodes tortugensis), and 188 were uninfected. We used the spatial scale at which gobies were clustered naturally (~4 m2) as an ecologically relevant neighborhood and measured goby density and the availability of refuges from predators within each goby's neighborhood. Goby survival generally declined with increasing density, and this decline was steeper for gobies with access to few refuges than for gobies in neighborhoods where refuges were common. The negative effects of high density and refuge shortage were also more severe for parasitized gobies than for gobies free of parasites. This parasite has characteristics typical of emerging diseases and appears to have altered the strength of a preexisting density-dependent interaction.

]]> Graham E. Forrester et al. Methane and Carbon Monoxide Production, Oxidation, and Turnover Times in the Caribbean Sea as Influenced by the Orinoco River http://digitalcommons.uri.edu/nrs_facpubs/22 http://digitalcommons.uri.edu/nrs_facpubs/22 Wed, 01 May 2013 09:48:34 PDT The surface distribution of CH4, photoproduction capacity of seawater for CO, and CH 4 and CO microbial oxidation rates and turnover times were determined for the surface waters of the southeastern Caribbean Sea and Gulf of Pafia as affected by the Orinoco River. Measurements were made during the spring (low fiver flow) and the fall (high fiver flow) in order to determine the influence of Orinoco River discharge on these parameters. Methane concentrations were generally lower in the fall than in the spring.L ow CH 4 oxidationr ates and similars urfaced istributionsw ere observedd uring both seasons. Methane oxidation in the fiver plume was significantly higher in the fall. Potential CO photoproduction and CO oxidation rates were generally higher during the fall. Possible effects of the Orinoco River on potential CO photoproduction capacity were observed as far as Puerto Rico. Turnover times for CH 4 were in the order of years, whereas CO turnover times were in the order of hours. The Orinoco River has a significant impact on the consumption of CO and CH 4 and the photoproduction of CO in the southeastern Caribbean Sea, presumably resulting from inputs of fivefine carbon and nutrients.

]]> Ronald D. Jones et al. Structure and composition of leachfield bacterial communities: role of soil texture, depth and septic tank effluent inputs http://digitalcommons.uri.edu/nrs_facpubs/21 http://digitalcommons.uri.edu/nrs_facpubs/21 Wed, 01 May 2013 08:47:19 PDT Although groundwater quality depends on microbial processes in the soil treatment area (STA) of onsite wastewater treatment systems (OWTS), our understanding of the development of these microbial communities is limited. We examined the bacterial communities of sand, sandy loam, and clay STAs at different depths in response to septic tank effluent (STE) addition using mesocosms. Terminal restriction fragment length polymorphism (TRFLP) analysis was used to compare the bacterial community structure and composition of STE, native soil prior to STE addition (UNX) and soil exposed to STE (EXP). Principal component analysis separated communities with depth in sand but not in sandy loam or clay. Indices of richness, diversity, and evenness followed the order: sandy loam > sand > clay. Analysis of TRF peaks indicated that STE contributed least to the composition of STA bacterial communities (5%–16%), followed by UNX soil (18%–48%), with the highest proportion of the community made up of TRFs not detected previously in either UNX or STE (50%–82%) for all three soils. Soil type and depth can have a marked effect on the structure and composition of STA bacterial communities, and on the relative contribution of native soil and STE to these communities.

]]> Jose A. Amador et al. Predators, Prey Refuges, and the Spatial Scaling of Density-Dependent Prey Mortality http://digitalcommons.uri.edu/nrs_facpubs/20 http://digitalcommons.uri.edu/nrs_facpubs/20 Fri, 29 Mar 2013 06:09:53 PDT We tested the biological cause of density-dependent mortality in the bridled goby (Coryphopterus glaucofraenum), a small coral reef fish, and evaluated whether this knowledge allowed us to detect density dependence at different spatial scales in natural habitats. To identify the biological cause of density dependence, we manipulated both population density and the availability of shelter (crevices used as refuges from predators) in small plots of continuous reef. We detected strong density-dependent mortality in plots with few refuges, but mortality was density independent in plots with abundant refuges, indicating that limited shelter causes density dependence. Predator density was unrelated to the density of gobies and refuges, suggesting that predators displayed a type III functional response in patches with few refuges. In a second experiment, we manipulated goby density within replicate plots of three sizes (4, 16, and 64 m2) that varied naturally in the availability of refuges. If refuge availability was ignored, mortality appeared to be density independent at all scales. If, however, plots were grouped by refuge availability, mortality was density dependent in plots with few refuges, but low and density independent in plots with many refuges at all spatial scales. Understanding the mechanism of density dependence (refuge shortage) was thus required to measure the strength of density dependence in natural, spatially variable, habitat. We suggest that density dependence was detectable in plots of different sizes because the relationships between the densities of gobies, refuges, and goby predators were similar across the spatial scales we studied. Our work demonstrates that identifying the biological interactions that cause density dependence, and characterizing the spatial domains at which those interactions operate, will be important to accurately assess the effects of density dependence on population dynamics.

]]> Graham E. Forrester et al. Spatial Density Dependence Scales up but Does Not Produce Temporal Density Dependence in a Reef Fish http://digitalcommons.uri.edu/nrs_facpubs/19 http://digitalcommons.uri.edu/nrs_facpubs/19 Fri, 29 Mar 2013 06:05:28 PDT Field experiments provide rigorous tests of ecological hypotheses but are typically of short duration and use small spatial replicates. We assessed empirically whether the results of experiments testing for density dependence applied at larger spatial domains and explained temporal population dynamics. We studied a small coral reef fish, the goldspot goby {Gnatholepis thompsoni), in the Bahamas. We assessed the effects of interactions with conspecifics and with an ecologically similar species, the bridled goby {Coryphopterus glaucofraenum). Two density manipulations on small reef patches revealed that goldspot goby mortality over one month increased as conspecifics became crowded. On five large natural reefs, we correlated the initial year-class density of both species (annual larval settlement) with the subsequent decline of goldspot goby year-classes for five years. Mortality was correlated with conspecific density among reefs for all years, but not among years for all reefs. Thus, spatial density dependence in mortality scaled up qualitatively from small patches to entire reefs but was not associated with temporal density dependence. Our results support the conclusion that field experiments may be extrapolated to larger spatial domains with care, but that using small spatial comparisons to predict temporal responses is difficult without knowing the underlying biological mechanisms.

]]> Graham E. Forrester et al. Inter-Cohort Competition Drives Density Dependence and Selective Mortality in a Marine Fish http://digitalcommons.uri.edu/nrs_facpubs/18 http://digitalcommons.uri.edu/nrs_facpubs/18 Fri, 22 Mar 2013 08:40:22 PDT For organisms with complex life cycles, the transition between life stages and between habitats can act as a significant demographic and selective bottleneck. In particular, competition with older and larger conspecifics and heterospecifics may influence the number and characteristics of individuals successfully making the transition. We investigated whether the availability of enemy-free space mediated the interaction between adult goldspot gobies (Gnatholepis thompsoni), a. common tropical reef fish, and juvenile conspecifics that had recently settled from the plankton. We added rocks, which provide refuge from predators, to one-half of each of five entire coral reefs in the Bahamas and measured the survival and growth of recent settlers in relation to adult goby densities. We also evaluated whether mortality was selective with respect to three larval traits (age at settlement, size at settlement, and presettlement growth rate) and measured the influence of refuge availability and adult goby density on selection intensity. Selective mortality was measured by comparing larval traits of newly settled gobies (postsettlement) with those of survivors (2-3 week postsettlement juveniles). We detected a negative relationship between juvenile survival and adult goby density in both low- and high-refuge habitats, though experimental refuge addition reduced the intensity of this density dependence. Juvenile growth also declined with increasing adult goby density, but this effect was similar in both low- and high-refuge habitats. Refuge availability had no consistent effect on selective mortality, but adult goby density was significantly related to the intensity of size-selective mortality: bigger juveniles were favored where adults were abundant, and smaller juveniles were favored where adults were rare. Given the typically large difference in sizes of juveniles and adults, similar stage-structured interactions may be common but underappreciated in many marine species.

]]> Jameal F. Samhouri et al. Using Long-Term Constant-Effort Banding Data to Monitor Population Trends of Migratory Birds: A 33-Year Assessment of Adjacent Coastal Stations http://digitalcommons.uri.edu/nrs_facpubs/17 http://digitalcommons.uri.edu/nrs_facpubs/17 Wed, 20 Mar 2013 08:30:44 PDT One technique for monitoring population trends of many species of migratory songbirds is to assess changes in population indices at constant-effort mist-netting stations located at sites of migration stopover. However, few studies have attempted to validate this approach. We compared long-term (1969–2001) population trends based on annual variation in capture rates at two banding stations located 30 km apart in southern Rhode Island, with one on the mainland, the other on an offshore island. Of 24 species with sufficient sample sizes, 21 species exhibited a significant linear decline at one or both stations. There was a high degree of conformity in trend-slope directions observed at each station. Annual fluctuations and trend magnitude conformed less well, although there was more concordance for nine transient species that do not breed in southern New England. At both stations trends were similar to those at a migration-monitoring station ~95 km away in coastal Massachusetts. The trends at this network of three migration-monitoring stations were more negative than those of Breeding Bird Surveys in northern New England and southeastern Canada. Our results demonstrate that constant-effort mist-netting stations could be used to monitor population trends of many species of migratory songbirds, although it is not clear which breeding populations are being monitored. This suggests that banding stations could be used to supplement existing large-scale monitoring programs.

]]> Jason E. Osenkowski et al. Are Wetland Regulations Cost Effective for Species Protection? A Case Study of Amphibian Metapopulations http://digitalcommons.uri.edu/nrs_facpubs/16 http://digitalcommons.uri.edu/nrs_facpubs/16 Wed, 20 Mar 2013 08:30:42 PDT Recent declines in amphibian populations have raised concern among conservation biologists, with habitat loss and degradation due to human activities among the leading causes. The most common policies used to protect the habitat of pond-breeding amphibians are wetland regulations that safeguard the wetland itself. However, many amphibians spend much of their adult lives foraging and over-wintering in upland habitats and exist as metapopulations with dispersal among ponds. With no consideration of lands in the dispersal matrix, wetland policies may be ineffective at protecting amphibians or other wetland species that disperse across the landscape. This paper examined the adequacy and cost effectiveness of alternative conservation policies and their corresponding land use patterns on the long-term persistence of pond-breeding amphibians in exurban landscapes. We used computer simulations to compare outcomes of wetland buffer policies and broader landscape wide conservation policies across a variety of landscape scenarios, and we conducted sensitivity analyses on the model's species parameters in order to generalize our results to other wetland species. Results showed that, in the majority of human-dominated landscapes, some amount of dispersal matrix protection is necessary for long-term species persistence. However, in landscapes with extremely low-intensity land use (e.g., low-density residential housing) and high pond density, wetland buffer policies may be all that is required. It is not always more cost effective to protect core habitat over the dispersal matrix, a common conservation practice. Conservation costs that result from forgone residential, commercial, or agricultural activities can vary substantially but increase in a nonlinear manner regardless of land use zoning. There appears to be a threshold around an average habitat patch occupancy level of 80%, after which opportunity costs rise dramatically.

]]> Dana M. Bauer et al. Components of Reproductive Effort and Yield in Goldenrods http://digitalcommons.uri.edu/nrs_facpubs/15 http://digitalcommons.uri.edu/nrs_facpubs/15 Tue, 12 Mar 2013 09:10:19 PDT Four components of reproductive yield (the weight of reproductive tissue) were examined in relationt o their effect on reproductive effort and their relative contributions to reproductive yield in five species of goldenrods (Solidago, Compositae). The yield components were number of flowing stems per plant, number of flowering branches per stem, number of flowering heads per branch, and number of seeds per seed head. Individuals within populations increase their reproductive effort by increasing their reproductive weight, not by decreasing their vegetative weight. Each species shows a different pattern of positive correlations of yield components with reproductive yield and reproductive effort, indicating that each species has its own mech-anisms for regulating reproduction. The yield components were not significantly intercorrelated.

]]> Richard B. Primack et al. BLUE-WINGED TEAL NESTING IN HAWAII http://digitalcommons.uri.edu/nrs_facpubs/14 http://digitalcommons.uri.edu/nrs_facpubs/14 Tue, 12 Mar 2013 09:10:18 PDT Peter W. C. Paton et al. Survival Estimates for Snowy Plovers Breeding at Great Salt Lake, Utah http://digitalcommons.uri.edu/nrs_facpubs/13 http://digitalcommons.uri.edu/nrs_facpubs/13 Tue, 12 Mar 2013 08:55:43 PDT Peter W. C. Paton Biosecurity: Moving toward a Comprehensive Approach http://digitalcommons.uri.edu/nrs_facpubs/12 http://digitalcommons.uri.edu/nrs_facpubs/12 Fri, 08 Mar 2013 11:20:19 PST Laura A. Meyerson et al. SITE FIDELITY, PHILOPATRY, AND SURVIVAL OF PROMISCUOUS SALTMARSH SHARP-TAILED SPARROWS IN RHODE ISLAND http://digitalcommons.uri.edu/nrs_facpubs/11 http://digitalcommons.uri.edu/nrs_facpubs/11 Fri, 08 Mar 2013 11:20:18 PST We investigated site fidelity and apparent survival in a promiscuous population of Saltmarsh Sharp-tailed Sparrows (Ammodramus caudacutus) in southern Rhode Island. Based on capture–recapture histories of 446 color-banded sparrows studied from 1993 to 1998 at our primary study site, Galilee, we observed significant variation in apparent survival rates among years, but not between sexes. Return rates of adult males (37.6%) and females (35.6%) were not significantly different during any year. Juveniles exhibited high return rates, ranging from 0 to 44%, with males (61% of returns) more likely to return than females (35%). In addition, we monitored movements of 404 color-banded sparrows at nine satellite marshes in 1997 and 1998, which supported our findings at Galilee and documented intermarsh movements by 10% of all banded birds. Lack of gender-bias in adult dispersal and strong natal philopatry of sparrows in Rhode Island occurs regularly among passerines possessing a variety of mating systems. Despite emancipation from parental and resource defense duties, adult male Saltmarsh Sharp-tailed Sparrows exhibited apparent survival rates similar to adult females. Availability of high-quality breeding habitat, which is patchy and saturated, may be the most important factor limiting dispersal for Saltmarsh Sharptailed Sparrows in Rhode Island. Received 5 January 2000, accepted 24 April 2001.

]]> DEBORAH A. DIQUINZIO et al. Mineralization of ancient carbon in the subsurface of riparian forests http://digitalcommons.uri.edu/nrs_facpubs/10 http://digitalcommons.uri.edu/nrs_facpubs/10 Mon, 04 Feb 2013 09:52:11 PST Microbial activity in saturated, subsurface sediments in riparian forests may be supported by recent photosynthate or ancient (>500 ybp) soil organic carbon (SOC) in buried horizons. Metabolism of ancient SOC may be particularly important in riparian zones, considered denitrification hot spots, because denitrification in the riparian subsurface is often C-limited, because buried horizons intersect deep flow paths, and because low C mineralization rates can support ecosystem-relevant rates of denitrification. Buried horizons are common where alluvial processes (stream migration, overbank flow) have dominated riparian evolution. Our objectives were to determine: (1) the extent to which ancient SOC directly supports subsurface microbial activity; (2) whether different C sources support microbial activity in alluvial versus glaciofluvial riparian zones; and (3) how microbial use of ancient SOC varies with depth. In situ groundwater incubations and 14C dating of dissolved inorganic carbon revealed that ancient SOC mineralization was common, and that it constituted 31–100% of C mineralization 2.6 m deep at one site, at rates sufficient to influence landscape N budgets. Our data failed to reveal consistent spatial patterns of microbially available ancient C. Although mineralized C age increased with depth at one alluvial site, we observed ancient C metabolism 150 cm deep at a glaciofluvial site, suggesting that subsurface microbial activity in riparian zones does not vary systematically between alluvial and glaciofluvial hydrogeologic settings. These findings underscore the relevance of ancient C to contemporary ecosystem processes and the challenge of using mappable surface features to identify subsurface ecosystem characteristics or riparian zone N-sink strength.

]]> Noel P. Gurwick et al. Improvement of Hydraulic and Water Quality Renovation Functions by Intermittent Aeration of Soil Treatment Areas in Onsite Wastewater Treatment Systems http://digitalcommons.uri.edu/nrs_facpubs/9 http://digitalcommons.uri.edu/nrs_facpubs/9 Wed, 05 Sep 2012 07:45:14 PDT We tested intermittent aeration of the soil treatment area (STA) of onsite wastewater treatment systems (OWTS) for its ability to restore and maintain STA hydraulic flow and improve the water quality functions of conventional OWTS. Evaluation was conducted on hydraulically-failed conventional OWTS at three state-owned medical group homes in Washington County, RI, USA. Testing was conducted in two phases, with Phase I (before intermittent soil aeration (ISA)) comprising the first 6 months of the study, and Phase II (during ISA) the remaining 7 months. Intermittent soil aeration restored STA hydraulic function in all three systems despite a marked reduction in the STA total infiltrative surface. Soil pore water was collected from 30 and 90 cm below the STA during both phases and analyzed for standard wastewater parameters. Although the STA infiltrative surface was reduced—and the contaminant load per unit of area increased—after installation of the ISA system, no differences were observed between phases in concentration of total N, NO3, total P, or dissolved organic carbon (DOC). Apparent removal rates—which do not account for dilution or differences in infiltrative area—for total N, total P, and DOC remained the same or improved during Phase II relative to the pre-operation phase. Furthermore, intermittent soil aeration enhanced actual removal rates —which do account for dilution and differences in infiltrative area. The effects of ISA on actual removal of contaminants from STE increased with increasing hydraulic load—a counterintuitive phenomenon, but one that has been previously observed in laboratory studies. The results of our study suggest that intermittent soil aeration can restore and maintain hydraulic flow in the STA and enhance carbon and nutrient removal in conventional OWTS.

]]> Jose A. Amador et al. Phenotopic Plasticity of Leaf Shape Along a Temperature Gradient in <i>Acer Rubrum</i> http://digitalcommons.uri.edu/nrs_facpubs/8 http://digitalcommons.uri.edu/nrs_facpubs/8 Wed, 05 Sep 2012 07:35:15 PDT Both phenotypic plasticity and genetic determination can be important for understanding how plants respond to environmental change. However, little is known about the plastic response of leaf teeth and leaf dissection to temperature. This gap is critical because these leaf traits are commonly used to reconstruct paleoclimate from fossils, and such studies tacitly assume that traits measured from fossils reflect the environment at the time of their deposition, even during periods of rapid climate change. We measured leaf size and shape in Acer rubrum derived from four seed sources with a broad temperature range and grown for two years in two gardens with contrasting climates (Rhode Island and Florida). Leaves in the Rhode Island garden have more teeth and are more highly dissected than leaves in Florida from the same seed source. Plasticity in these variables accounts for at least 6–19 % of the total variance, while genetic differences among ecotypes probably account for at most 69–87 %. This study highlights the role of phenotypic plasticity in leaf-climate relationships. We suggest that variables related to tooth count and leaf dissection in A. rubrum can respond quickly to climate change, which increases confidence in paleoclimate methods that use these variables.

]]> Dana L. Royer et al. Hybridization of common reed in North America? The answer is blowing in the wind http://digitalcommons.uri.edu/nrs_facpubs/7 http://digitalcommons.uri.edu/nrs_facpubs/7 Fri, 03 Aug 2012 09:37:14 PDT Background and aims: We review evidence for hybridization of P. australis in North America and the implications for the persistence of native Phragmites australis ssp. americanus populations in North America. We also highlight the need for an updated classification system, which takes P. australis intraspecific variation and hybridization into account.

Methodology: We reviewed available published, in press, and in preparation literature to assess the likelihood of hybridization and interbreeding in genotypes of Phragmites australis present in North America.

Principal results: Experimental results demonstrate that hybridization among introduced and native haplotypes is possible within the genus Phragmites, yet evidence that hybridization has naturally occurred is only starting to emerge. The lag in identifying hybridization in Phragmites in North America may be related to undersampling in some parts of North America and to a lack of molecular tools that provide the capability to recognize hybrids.

Conclusions: Our understanding of the gene flow within and between species in the genus Phragmites is moving at a fast pace, especially on the east and Gulf coasts of North America. More attention should also be focused on the Great Lakes region, the southwestern and the west coast of the U.S. where sympatry has created opportunities for hybridization. Where hybridizations have been detected, there is currently no published data on how hybridization affects plant vigor, morphology, invasiveness, or conservation of the genetic integrity of the North American native subspecies. We conclude that detection of more hybridization is highly likely and that there is a need to develop new markers for the different Phragmites species and lineages to fill current knowledge gaps. Finally, we suggest that the classification system for P. australis should be updated and published to help clarify the nomenclature.

]]> Laura A. Meyerson et al. Mapping Shallow Coastal Ecosystems: A Case Study of a Rhode Island Lagoon http://digitalcommons.uri.edu/nrs_facpubs/6 http://digitalcommons.uri.edu/nrs_facpubs/6 Wed, 01 Aug 2012 06:56:03 PDT In order to effectively study, manage, conserve, and sustain shallow-subtidal ecosystems, a spatial inventory of the basic resources and habitats is essential. Because of the complexities of shallow-subtidal substrates, benthic communities, geology, geomorphology, and water column attributes, few standard protocols are fully articulated and tested that describe the mapping and inventory processes and accompanying interpretations. In this paper, we describe a systematic approach to map Rhode Island’s shallow-subtidal coastal lagoon ecosystems, by using, integrating, and reconciling multiple data sets to identify the geology, soils, biological communities, and environments that, collectively, define each shallow-subtidal habitat. We constructed maps for these lagoons via a deliberate, step by step approach. Acoustics and geostatistical modeling were used to create a bathymetric map. These data were analyzed to identify submerged landforms and geologic boundaries. Geologic interpretations were verified with video and grab samples. Soils were sampled, characterized, and mapped within the context of the landscape and geologic boundaries. Biological components and distributions were investigated using acoustics, grab samples, video, and sediment profile images. Data sets were cross-referenced and ground-truthed to test for inconsistencies. Maps and geospatial data, with Federal Geographic Data Committee (FGDC)-compliant metadata, were finalized after reconciling data set inconsistencies and made available on the Internet. These data allow for classification in the revised Coastal and Marine Ecological Classification Standard (CMECS). With these maps, we explored potential relationships among and between physical and biological parameters. In some cases, we discovered a clear match between habitat measures; in others, however, relationships were more difficult to distinguish and require further investigation.

]]> Mark Stolt et al. Ecological and socioeconomic impacts of invasive alien species in island ecosystems http://digitalcommons.uri.edu/nrs_facpubs/5 http://digitalcommons.uri.edu/nrs_facpubs/5 Tue, 31 Jul 2012 13:34:42 PDT Minimizing the impact of invasive alien species (IAS) on islands and elsewhere requires researchers to provide cogent information on the environmental and socioeconomic consequences of IAS to the public and policy makers. Unfortunately, this information has not been readily available owing to a paucity of scientific research and the failure of the scientific community to make their findings readily available to decision makers. This review explores the vulnerability of islands to biological invasion, reports on environmental and socioeconomic impacts of IAS on islands and provides guidance and information on technical resources that can help minimize the effects of IAS in island ecosystems. This assessment is intended to provide a holistic perspective on island- IAS dynamics, enable biologists and social scientists to identify information gaps that warrant further research and serve as a primer for policy makers seeking to minimize the impact of IAS on island systems. Case studies have been selected to reflect the most scientifically-reliable information on the impacts of IAS on islands. Sufficient evidence has emerged to conclude that IAS are the most significant drivers of population declines and species extinctions in island ecosystems worldwide. Clearly, IAS can also have significant socioeconomic impacts directly (for example human health) and indirectly through their effects on ecosystem goods and services.These impacts are manifest at all ecological levels and affect the poorest, as well as richest, island nations. Themeasures needed to prevent and minimize the impacts of IAS on island ecosystems are generally known. However, many island nations and territories lack the scientific and technical information, infrastructure and human andfinancial resources necessary to adequately address the problems caused by IAS. Because every nation is an exporter and importer of goods and services, every nation is also a facilitator and victim of the invasion of alien species.Wealthy nations therefore need to help raise the capacity of island nations and territories to minimize the spread and impact of IAS.

]]> Jamie K. Reaser et al.