Biological Invasions最新文献

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.

Invasive species can have complex direct and indirect impacts on ecosystems. The impacts of invasive prey species on native prey can be difficult to observe if the latter migrate seasonally, and when the interaction is indirect. We hypothesize that invasive lagomorphs and snow dynamics indirectly drive predation risk for guanaco by puma. We employed camera-trapping data collected over multiple years and seasons in an altitudinal gradient in the Andes of Central Chile. We predicted a high spatial and temporal association between puma and lagomorph detections, given these prey species comprise most of puma diet in the area. We also expected a higher spatiotemporal association between guanaco and puma detections towards higher snow cover in the study area, because of downward altitudinal migration of the ungulate. We obtained 4863 mammalian detections. Our data shows that the detection of puma was positively associated with hare capture rate year-round. In addition, puma detection was positively associated with the interaction of snow cover and guanaco capture rate. Puma temporal activity strongly overlapped with hare, whereas puma apparently increased diurnal activity with an increase in guanaco capture rate. Predation risk for guanaco increased when snow cover was higher and decreased when guanaco migrated to higher altitudes during dryer months. We conclude it is of conservation concern that lagomorphs may be subsidizing pumas and modifying patterns of consumptive and non-consumptive effects of the predator on native prey populations.

Estimates of the cost of damage caused by invasive alien speices and the money spent addressing biological invasions are needed to guide policy and management. Here, we quantify the known monetary costs of biological invasions to South Africa, using data from the InvaCost database, literature searches, and stakeholders. The Department of Forestry, Fisheries and the Environment, and agencies directly funded by them, provided most of the information on money spent, with very little information was available from other government agencies and the private sector. There was also very little information on the monetary costs due to the impacts of invasions. Between 1960 and 2023, ZAR9.6 billion (adjusted to 2022 values) was spent managing biological invasions in South Africa. This is only 4% of the money predicted as being necessary for management, which amounted to ZAR231.8 billion in 2022 values. There is uncertainty in the obtained estimates due to a paucity of information on both impacts and management costs. A few key points emerged from our analysis: the cost of damage caused by invasions far exceeds expenditure on control; the amount spent on control is much less than what is predicted to be needed; almost all management has focussed on a few invasive plant species; and there are large gaps in information that reduce the confidence in our estimates. Transparent cost reporting, strategic public–private collaborations, standardised impact metrics, and reliable assessments of management effectiveness are needed to enable South Africa to more effectively account for and prioritise investments.

The aquarium pet trade is one of the leading pathways for the introduction of invasive species into natural ecosystems. In 2018, we surveyed pet shops across South Africa to obtain a checklist of ornamental fish species in the aquarium pet shop trade and to assess their invasion potential using sourced data (e.g., natural environment, native range, introduction status, impact status and climatic zone). We evaluated selected common aquarium fish species with high invasion potential according to previous invasion history. We highlighted the need for the development of a management strategy for the aquarium pet trade in South Africa. We identified 312 fish species belonging to 77 families and 182 genera. Most pet shops were in Gauteng Province (n = 38), with few in Limpopo Province (n = 3). Gauteng had the highest number of fish species (n = 271), while North West Province had the lowest number (n = 95). Pet shops were dominated by freshwater species (68%), followed by marine species (22%), while the origin of 30 species (10%) was transitional aquatic ecosystems. Most freshwater taxa were native to South America and Asia, while most marine species were from the Pacific and Indo-Pacific Oceans. Most (88%) species were tropical, 10% subtropical, and 1% temperate. Several (n = 28) species had more than 50% frequency of occurrence, representing the most popular ornamental fishes. Several (n = 13) species are invasive in South Africa and other parts of the world. The system of importation of ornamental fish in South Africa is not clear. Although there is a recommendation that these importations must be regulated according to the whitelist and blacklist in South Africa, it is not clear how this is implemented in practice. We demonstrated a high risk of alien fish species introduction in South Africa through the aquarium pet shop trade.

Conflicting hypotheses regarding the factors underlying the invasibility of plant species persist, as portrayed by Darwin’s naturalization conundrum. This is particularly critical in arid and semiarid ecosystems, for which understanding remains elusive. We test how similarities between exotic and native plants in the Brazilian semiarid Caatinga affect the invasion stage and distribution of invasive species. We estimate diversity fields for exotic species, representing the composition of native species that co-occur with each exotic species and calculated phylogenetic metrics of the distance of focal species to its field. We also assess whether changes in stage from exotic to naturalized and from naturalized to invasive are influenced by phylogenetic relatedness and functional traits. We also test whether the observed phylogenetic distance values of the invasive species differ from those expected by chance. Finally, we analyze whether there are functional similarities between the stages of exotic species and native plants. Plants that are phylogenetically closer to the more frequent native species of the Caatinga are more likely to become naturalized and invasive. Among invasive species with a significant pattern of phylogenetic relatedness, those that are closer to native species are more prevalent. Naturalized and invasive plants are shorter and have smaller leaves and seeds than native plants. The observed functional differences suggest that naturalized and invasive species adopt strategies similar to those of competitive native plants, such as seed bank formation and dense populations.

Mitigating exotic species invasions requires reliable information on abundance and source-sink dynamics to evaluate effectiveness of control efforts. Despite being present in the southeastern United States for centuries, wild pigs (Sus scrofa) continue to invade new areas, including the Sam D. Hamilton Noxubee National Wildlife Refuge (NNWR) in Mississippi, a forested landscape with an emerging wild pig population. Considering the early stage of invasion, we designed and implemented a non-invasive hair sampling technique to estimate abundance and relatedness of wild pigs within the NNWR. Following 8-week sampling periods in 2021 (n = 160 samples) and 2022 (n = 159 samples), we identified 38 and 26 unique individuals, respectively, although recapture rates were too low to yield precise abundance estimates. We also identified low heterozygosity indicating high relatedness among our population which likely reflected lack of barrier features to gene flow and/or a limited number of external source populations. Finally, we observed positive trends in viable samples collected relative to sampling week, suggesting more optimal sampling period(s) may exist (e.g., autumn). We also acknowledge that use of grain in more accessible areas rather than our remote approach using scent-only attractants may increase hair snare attractiveness and wild pig encounters, while permitting increased sampling frequency. Collectively, these modifications (i.e., altered season, bait type, and access) provide viable pathways to increase precision for abundance estimates. When used concomitantly with ongoing monitoring and control efforts, non-invasive hair sampling will contribute to a more holistic understanding of this exotic species and better inform management actions.

Seed predation by rodents can act as a recruitment barrier during community assembly, limiting the establishment of exotic species. Predation rates of exotic seeds may depend on their attractiveness, determined by their traits, and how different they are from natives. Additionally, at the naturalization stage of the invasion process, exotic seeds may escape post-dispersal predation because they are rare in the community. To test these ideas, we assessed granivory in a Patagonian forest, where two species with contrasting seed sizes are naturalized. Rubus idaeus seeds are of similar size of natives, whereas Prunus cerasus seeds are four times larger. The relative abundance of their seeds within the landscape is low compared to native seeds. Throughout the fruiting season, we offered seeds from all species present in the community (native and exotics), whenever they were available in the landscape. To consider the effects of vegetation structure on rodent foraging behavior, we offered seeds in areas with and without understory cover. We found a hump-shaped relationship between predation rates and seed size. Consequently, rodents strongly avoided large exotic Prunus seeds, but removed Rubus seeds at similar rates to natives. Contrary to our expectations, seed abundance did not affect predation, and hence, rarity did not confer an advantage to exotic seeds. The presence of shrub cover increased 2.3 times the removal rates compared to open areas. We suggest that the dissimilarity in seed size compared to native species and the presence of shrub cover influenced predation pressure on exotic species within our community.