Biological Invasions最新文献

The spread of marine non-indigenous species (NIS) is driven largely by shipping and global trade. Biofouling on vessel hulls is a major source of invasions, but many biofouling organisms are sessile (non-motile) and require reproduction, which often produces mobile, waterborne propagules (e.g., larvae) that can colonize new regions. The ability of biofouling organisms to reproduce, however, can depend strongly on abiotic conditions at the time of reproduction but also potentially prior to any reproductive event. For many organisms, past environments can influence performance later in life via within-generation carryover effects, but how carryover effects influence potential NIS introductions is unclear. We conducted a laboratory experiment to explore within-generation carryover effects of salinity and how they operate across different environments in the barnacle Amphibalanus improvisus, a common biofouling organism. We exposed newly settled barnacles to two different salinities (15 and 28 psu) for three weeks, maintained them in a common salinity for five weeks, then re-exposed them to the two initial salinities in a fully-factorial design prior to measuring their reproductive output. We found that barnacles that switched salinities between the initial and final exposures tended to produce more nauplii larvae (up to 50%) than those that remained in the same salinity conditions, possibly because of a stress response induced by physiological acclimation to early life environments. Because adult biofouling species are likely to be exposed to variable environmental conditions during vessel transits, carryover effects and their impact on propagule output may be important to consider when evaluating potential NIS introductions via biofouling.

The golden twin-spot moth, Chrysodeixis chalcites Esper (Lepidoptera: Noctuidae), is a polyphagous, polyvoltine crop pest occurring natively from northern Europe to Mediterranean Africa and the Canary Islands. Larvae feed on a wide variety of naturally occurring plants as well as soybean and other legume crops, short staple cotton, tomato, potato, peppers, tobacco, and banana. Chrysodeixis chalcites has been recorded in agricultural lands in the Ontario peninsula in eastern Canada and in northern counties of Indiana, USA. Given the strong potential for C. chalcites to invade USA crop lands, it is important to identify environments most likely to sustain growing populations of this pest. Though C. chalcites is native to Europe and North Africa, it has invaded sub-Saharan Africa. Using occurrence data form the native and invaded ranges, and environmental predictors including bioclimatic conditions and human disturbance, we trained three ecological niche models to estimate an ensemble prediction of environmental suitability in the contiguous US. Because human impact is potentially a confounding predictor, models were trained both with and without it. High environmental suitability was projected for the Atlantic coast from New England to Florida, the Gulf coast, the lower Midwest, and the Pacific coast and Central Valley of California.

Solidago gigantea, a notorious invasive species in Europe and Asia, has been shown in previous studies to impact soil properties such as nutrient availability and pH. However, the strength and direction of these alterations have varied across studies. Additionally, the species reduces species richness in invaded communities, though the susceptibility of different plant communities to invasion remains unclear. To address these inconsistencies, we investigated invasion effects on soil properties and plant communities across various soil types, nitrogen and pH levels, and plant communities. Soil samples were collected from invaded and nearby uninvaded plots, with measurements taken for extractable nitrogen, pH, and moisture content. Plant species richness, diversity, Sorensen similarity, mean Ellenberg indicator values and some community mean plant traits were compared between invaded and uninvaded plots. Lastly, S. gigantea stand density and size in invaded plots were quantified. Solidago gigantea significantly altered soil extractable-N and pH, with the extent and direction of changes depending on initial soil conditions. Alterations were most pronounced in acid, N-poor soils. Species richness and diversity consistently decreased in invaded plots. However, this decline was not due to direct competition with native species but to the replacement of specialized, local plant communities with less diverse, fast growing generalist communities adapted to fertile habitats. Solidago gigantea acts as an invasive ecosystem engineer, modifying soil conditions after introduction. This not only facilitates its spread but also leads to lasting effects that can persist even after its removal. Further studies on other invasive species are needed to establish general patterns due to their varied effects on ecosystem properties.

An increase in the establishment and spread of invasive alien plant species (IAPS) poses significant socioeconomic and environmental impacts. This study aimed to detect potential variations in the density, biomass, and fruit and seed production of Argemone mexicana L. IAPS along with land uses and agroecologies in south Wollo, Ethiopia. Using a stratified sampling method, eight kebeles, which are Ethiopia’s small administrative divisions, were sampled. The data were collected from four land use types covering two agroecology. One-way ANOVA, Tukey’s HSD test, and an independent t-test were used to examine the differences between land use and agroecology respectively. The associations of density, biomass, fruit, and seed density with slope and elevation were assessed using simple linear regression, using R4.2.1 program software. The mean A. mexicana ha⁻¹ s’ varied, significantly from 19,000 to 82,416 and 35,079 to 47,062, the aboveground dry biomass in kg m⁻² was 0.032 to 1.59 and 0.1395 to 0.689, and the belowground dry biomass in kg m⁻² was 0.048 to 0.506 and 0.0988 to 0.2408 between land use and agroecology respectively. The mean fruit per A. mexicana varied from 19 to 97 and 35 to 56, and seed per fruit of A. mexicana was 330 to 400 and 351 to 378 between land use and agroecology, respectively. As the slope and elevation increased, the values of all the measured variables decreased. Grazing land and highland agroecology had the lowest mean values, whereas farmlands and agroecology in the midlands had the highest values. Intervention should began in farmland and midland agroecology to prevent A. mexicana invasion.

Invasive mammalian predators are a key threat to native fauna globally. Island ecosystems that developed in isolation from mammals are particularly threatened by introduced mammalian predators. This is the case in New Zealand, where introduced mammalian predators have caused the decline of native birds, lizards, and invertebrates. In alpine areas of New Zealand, predator control targets stoats, rats, and cats as they are recognised as the key threats to native birds. Mice, which are known predators of invertebrates at lower elevations, are not actively controlled. As a result, alpine invertebrates in New Zealand represent an ideal focus for a natural experiment to understand the effects of predator control efforts and invasive mice on native invertebrates that evolved in isolation from mammals. In the Fiordland region of New Zealand, we assessed the large-bodied alpine invertebrate community at eight different sites that vary in their occurrence of mice and control of higher-order predators. We found that the recent presence of mice influenced the invertebrate community: wētā (a group of native orthopterans) were less common at sites where mice were present, and the mean body size of invertebrates collected in pitfall traps was larger at sites where mice were absent compared to sites where they were present. Control of other predators (specifically rats and mustelids) did not influence invertebrate body size, abundance, or community composition. Our findings suggest that, as in lowland environments, mice are an important predator of large-bodied invertebrates in the alpine zone and should be incorporated into future predator management programmes.

Islands harbor a significant proportion of global biodiversity and also have disproportionately high richness of introduced species relative to continents. Given the sensitivity of island ecosystems to introduced species, data deficiencies on introduction pathways, patterns of establishment, and potential impacts of introduced species can hamper mitigation and conservation efforts on islands. The Caribbean region is emerging as a hotspot for introduced amphibian and reptile (herpetofaunal) species, but patterns associated with herpetofaunal introductions on specific islands are not well explored. Here, we perform a detailed investigation of Aruba, a small Caribbean island with an exceptionally high number of introduced herpetofaunal species. We compile a database from the literature of introduction pathways, introduction years, source locations, native ranges, establishment outcomes, habitat use, and ecological impacts for three newly documented species and the 12 previously documented introduced herpetofaunal species on Aruba. From this database we synthesize emergent introduction patterns on Aruba and highlight areas of data deficiency. Overall, the patterns on Aruba echo the patterns exhibited in the greater Caribbean region. Introduction rates on Aruba have been increasing exponentially, yet the introduction pathways and source locations of most species are unknown. Following introduction, most species successfully establish localized populations in anthropogenic habitat, but the ecological impacts of most species have not been well-assessed. We suggest increased monitoring of shipments will help identify potential pathways to slow the introduction of new species, and further studies of ecological impacts of introduced species are needed.

Biological invasions are significant threats to biodiversity and are often exacerbated by human activities. This study consolidates occurrence data of Eriotremex formosanus (Matsumura) (Hymenoptera: Siricidae), models its ecological niche, and analyzes spatial congruence with global Pinus L. occurrences to identify at-risk areas across continents. Through a combination of techniques utilizing distribution records and environmental predictor variables, the study predicts the E. formosanus ecological niche. The models show high accuracy with AUC values of 0.959 ± 0.023, TSS of 0.852 ± 0.048, and Jaccard coefficients of 0.865 ± 0.037. The findings reveal a widespread global suitability for E. formosanus, encompassing previously unreported regions in Papua New Guinea, South Korea, Europe, Africa, and Australasia, with notable suitability in the Americas and a well-established presence from Japan to India in Asia. South American regions from northern Guyana to western Venezuela and along the Brazilian Atlantic coast are particularly suitable. The identified suitable areas significantly overlap with Pinus occurrences, primarily in temperate zones, pinpointing potential regions at invasion risk. Additionally, we recorded for the first time the occurrence of E. formosanus in South America. Given the recent discovery of this species in Brazil, this overlap necessitates urgent attention to potential invasion regions and pathways. The study underscores the importance of focused sampling in potential distribution areas and highlights the utility of ecological niche modeling in predicting and managing the spread of invasive species.

Quantifying attitudes towards invasive alien species (IAS) is fundamental to understanding the extent to which conservation scientists agree and can collaborate in their management. We tested the IAS Management Attitude scale (IMA), a shortened version of the Pest Management Attitude Scale, originally invented to quantify attitudes towards pests in New Zealand, as a tool to quantify broader attitudes towards IAS among bioinvasion experts in Italy. We administered an online questionnaire to a sample of experts working on biological invasions in Italy. We collected 316 answers, both from conservation practitioners (26.6%) and researchers (73.4%), and we used structural equation modeling to test for the psychometric properties of the scale and compare attitude scores between groups. The scale showed both a good reliability (Cronbach’s alpha = 0.7), validity (CFI = 0.99, TLI = 0.99, SRMR = 0.03, RMSE = 0.02) and measurement invariance, when comparing researchers and practitioners, as well as when comparing respondents working on different invasive taxa. Both researchers and practitioners, as well as respondents of a different age, had similar attitudes about IAS and their management. Our study shows that this shortened version of PMA scale, a simple scale originally conceived to measure attitudes towards invasive alien mammals, could indeed be used to quantify the attitudes of experts towards IAS, even in countries where the public debate about biological invasions is much more recent than in New Zealand. The scale could potentially be used both for large-scale and long-term research about the attitudes of experts about IAS.

It has become increasingly apparent that even mature forests are susceptible to plant invasions. However, invasive plants are often more abundant in younger forest stands. It is difficult to disentangle possible mechanisms that would explain this pattern due to the scarcity of long-term studies in successional forests. Several mechanisms have been proposed to explain patterns of invasions as forests age, including biotic resistance, window of opportunity, historical legacies, and invasion debt. We explored patterns and potential mechanisms of plant invasions over 70 years in a regenerating forest with different land-use histories in the Bolleswood Natural Area, Connecticut, USA. We examined how environmental factors related to colonization patterns of invasive and non-invasive introduced species over time, and whether these patterns were consistent with the proposed mechanisms. Non-invasive introduced species declined rapidly with canopy closure, while many invasive plants persisted or even increased over time as the forest aged. Colonization was focused in younger post-agricultural areas, although this declined with time. Dispersal distance, soil conditions, and land-use history played important roles in patterns of colonization, while the effect of shading was less clear. There was some evidence for each mechanism, but the relative importance of each mechanism was species-dependent, making generalizations about how invasive plants invade forests difficult. We found that land-use history impacted invasion more strongly than forest age, but over time even mature forests were slowly being invaded by some species. Thus, invasive species management may be required even in mature forests.

Reproductive success is a strong determinant of invasive species success. It is common for studies on invasive species to assess reproduction by measuring size-specific fecundity and scaling this up using population size or densities. Yet, reproductive success is influenced by numerous factors that are not accounted for in such calculations. We examined the influence of several factors on fecundity (clutch size) and egg size in the Asian shore crab Hemigrapsus sanguineus, including body size, spatial variation throughout the invaded range, season, fertilization success, brood loss, and diet. We show that all of these factors influence reproduction simultaneously within the invaded North American range of this species, though the relative importance of these different factors varied across sites or sampling times. Our study demonstrates that numerous factors may influence the reproductive success of invasive species and that studies that rely on fecundity measured at a single place and time, or that ignore factors such as offspring quality or brood loss, may provide a skewed picture of reproduction, and thus of potential invasive success.