Biological Invasions最新文献

Until recently, the Kara Sea was a stable ecosystem unaffected by alien species invasions. However, at the beginning of the twenty-first century, the snow crab (Chionoecetes opilio) was detected. Studies conducted between 2013 and 2022 in Blagopoluchiya Bay (Novaya Zemlya Archipelago, Kara Sea) provided an opportunity to observe the establishment of a population of this species and its influence on benthic communities. Various sampling methods, such as trawl and grab surveys, as well as video observations, were used to study two main seabed habitats, one in the deep inner basin and the other at the sill at the bay’s exit. The study revealed significant changes in benthic ecosystems, including declines in integral benthic characteristics such as abundance, biomass, diversity, and shifts in dominant species. The response of megabenthos and macrobenthos varied between habitats, but in general, there was a sharp decline in the abundance of large bivalves and brittle stars. The observed changes were not related to environmental variability but most likely to the abundance and size structure of the snow crab. The taxonomic and size structure of the benthos changed as crab individuals increased in size, and the changes were faster and more pronounced in the area with higher crab abundance. These findings raise concerns about the potential long-term effects of the snow crab invasion on the Kara Sea ecosystem, including reduced biodiversity and changes in food webs.

This study addresses the broader issue of invasive species management, particularly within the context of highly biodiverse yet threatened ecosystems such as the Atlantic Forest in Brazil. Effective management strategies are paramount to mitigate the ecological impact of invasive species on native ecosystems. Using the case of Artocarpus heterophyllus Lam. (Moraceae), a tree native to Southeast Asia that has become invasive in some urban tropical forests in Brazil, we developed a management approach based on the tree’s life cycle and vital rates. Our disturbance analysis showed that a management strategy focused on the survival and growth of JUVENILES 1 and ADULTS 1 would be effective in reducing the population growth rate (λ). Elasticity analyses, on the other hand, indicate that the best management options are those based on the survival rates of JUVENILES 1, ADULTS 1, and ADULTS 2. To reduce the population’s λ, our management simulations suggest that small interventions are sufficient, targeting a reduction of up to 5% in survival rates, particularly in the reproductive classes. In contrast, our simulations highlight that interventions involving the removal of 30% of the population or more per year have a minimal effect on reducing the population growth rate, while gradual, long-term management is more effective. Excessive management, defined as large-scale interventions that can open large gaps in the forest (e. g. exceeding 70% removal per year), would be unnecessary, could result in the waste of financial resources, and could hinder native species’ ability to colonize the environment.

Ecosystems worldwide are struggling with increasingly high levels of human-induced stressors, impacting their ecological health at local, regional, and global scales. Among the factors affecting freshwater organisms, temperature stands out, especially given the recent escalation of global warming, with possible adverse effects. In this study, we examined the basal levels of oxidative stress parameters in the round goby Neogobius melanostomus, spanning its native and non-native ranges of occurrence. We aimed to assess five populations across transcontinental scale (Turkey, Croatia, Slovakia, Poland, Finland) to determine whether individuals already experiencing conditions other than their thermal optimum (such as those in Turkey and Finland) would display elevated non-enzymatic indicators (level of lipid peroxidation and reduced glutathione levels) and enzymatic indicators (activity of glutathione peroxidase and catalase activity) of oxidative stress compared to those inhabiting milder ecosystems. The results obtained did not align with our initial predictions. The native Turkish population exhibited the lowest values for both antioxidants and oxidative damage, indicating an efficient redox system in this species. All tested parameters showed variation among populations, as well as between tissues and sexes. Temperature did not emerge as significant factor in any of the parameters tested, while for glutathione peroxidase, our analysis indicated a positive relationship with enzyme activity and salinity. The lack of a continuous latitudinal pattern in the non-native populations suggests the species’ potential for adaptive shifts, indicating superior adaptive abilities, especially in human affected ecosystems, rather than strictly adhering to environmental gradients.

The prevention of aquatic invasive species is one of the most cost-effective management strategies for reducing negative ecological, economic, and social impacts to freshwater ecosystems. The release of leftover baitfish via the live bait trade has been identified as a high-risk pathway for introducing invasive species beyond physical barriers (e.g., mountains, dams). To assess differences in behavior surrounding live bait use and angler knowledge of invasive species, we conducted in-person angler surveys at waterbody access sites (i.e. boat ramps with available shore fishing and a shore fishing location with no boat ramp) along the Missouri River, above and below Gavins Point Dam (Yankton, South Dakota, USA). We were primarily interested in whether angler behavior and knowledge differed among fishing locations over the course of a year because of potential variation in risk. Gavins Point Dam is impervious to fish passage and prevents the spread of invasive silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis (collectively known as bigheaded carp), but bigheaded carp could be transported above this dam by the use of live baitfish. Regardless of where respondents fished (above the dam/carp absent, below the dam/carp present, or both), 70% ± 11.12 of anglers used live baitfish and 57% ± 3.14 participated in ‘higher risk’ baitfish practices including release. Knowledge of bigheaded carp was limited, as only 2% ± 1.31 of respondents identified both bigheaded carp as invasive in an image collage, 51.82% ± 4.48 could not identify where invasive carp are present/absent, and 40% ± 3.34 of anglers had not received any information regarding bigheaded carp. These findings highlight limitations in angler knowledge, compliance, and identification of native and invasive species. Future implementable actions could include invasive species and baitfish release outreach via electronic media sources or additional signage that address these knowledge gaps.

The reproductive strategy of the European bitterling (Rhodeus amarus) involves an obligatory parasitic relationship with freshwater mussels from the family Unionidae. This study sets out to assess the possible threat that the invasive unionid species Sinanodonta woodiana poses to bitterling. The objective was accomplished by analysing the bitterling's reproductive preferences for S. woodiana and four native species of unionid mussels (Anodonta anatina, Unio crassus, U. pictorum and U. tumidus). We performed three experiments in a sand bottom tank. Experiments A and B lasted 20 for days and experiment C lasted 10 days. The highest numbers of eggs and embryos of bitterling in the experiment A were found in A. anatina. On the other hand, U. tumidus had the greatest number of embryos in the most developed embryonic stage (stage VI), followed by U. crassus, U. pictorum and lastly A. anatina, whereas U. crassus had the largest densities of eggs and embryos per unit gill area in cm². As hypothesized, S. woodiana did not contain a single egg or embryo which was also confirmed in the experiments B and C. Results of the experiment C had shown that the first few days bitterlings laid eggs in Unio spp. and only after that in A. anatina. Furthermore, it is evident that bitterlings favour mussels without glochidia. In conclusion, European bitterling will be threatened if an invasive species S. woodiana outcompetes the native unionid species.

Invasive ants are among the world’s most damaging invaders and are considered a significant threat to urban, natural, and agricultural habitats worldwide. Populations of invasive ants are notoriously difficult to eradicate once established and are typically managed using chemical tools, predominantly toxic baits and residual sprays. Most studies evaluating control efforts do not quantify post-treatment community-level response to control efforts, so the overall outcome of management efforts remains unknown and the efficacy of management efforts in mitigating invader impacts remains unclear. The potential of insecticide treatments to cause secondary ant invasions has not been previously examined. Secondary ant invasions, the proliferation of non-target invasive ants following efforts to suppress the dominant target invader is a potentially ubiquitous, yet rarely studied problem. Additionally, limited understanding of the interactions between co-occurring invaders can be problematic for predicting how the removal of only one invasive, a common management scenario, will affect the other invaders and native communities. The current study reports on the potential threat of secondary ant invasions following insecticide treatments and highlights future research needs to address this problem. Residual spray insecticide treatments were applied in an urban setting to control the invasive Argentine ant, Linepithema humile. While the study was limited to a single geographic area, results demonstrate that insecticide treatments can affect target and non-target species in unpredicted ways. Specifically, insecticides applied to control invasive L. humile provide effective short-term control but degrade relatively quickly and lead to secondary invasions by other invasive ants. Therefore, insecticide treatments are capable of causing secondary invasions by multiple invaders. Results demonstrate that invasive ant control is not simply precision removal of the target invader but a form of ecological disturbance with multiple positive and negative impacts on the ecosystem.

Community resistance plays a crucial role in the successful invasion of alien plants. However, our understanding of how soil legacy effects of native species richness, parasitic plants, competition and soil microbes contribute to community resistance remain unclear. To compare the legacy effects of soil conditioning and the current effects of plant interactions, we performed an experiment in which Chromolaeana odorata (invader) growth was measured with or without competition on live and sterile soils with different conditioning histories (species richness). Overall, our research indicated that C. odorata outperformed two native species across treatments, however, this advantage was smaller on soils with species rich histories and with competition from current plant growth. Our findings also revealed that both the soil legacy effects of native richness and competition negatively impact the growth of C. odorata, and native plants tend to produce more biomass in soils with greater diversity and under competitive conditions (5.0%). Interestingly, the holoparasitic plant C. chinensis decreased native plant growth (− 40%) more than C. odorata growth (− 11%). Further, C. chinensis did not parasitize C. odorata on sterilized soil. Furthermore, C. odorata did not experience limitations from parasitism in sterilized soil, as indicated by a slight increase in biomass of 2.3%. These results indicated that soils with diverse plant histories, competition from native plants, and lower C. chinensis parasitism will synergistically decrease C. odorata invasion. This study underscores that community resistance to C. odorata is governed by an interplay of multiple biotic factors, both individually and in combination. Simultaneously, this study contributes to a theoretical foundation for understanding the successful invasion of alien plants.

The Argentine ant is one among the 100 worst invasive animal species of the world. It has invaded six continents, and poses significant threats to the native invertebrate fauna. Prior knowledge on the suitable ecological niches of Argentine ants may help to devise better management plans. This study delineates the niches of Argentine ants using the ecological niche modeling approach by maintaining the temporal match between the distributional information and environmental data. We used an exhaustive methodological framework to understand the niche characteristics of Argentine ants in their native and invaded ranges. The model developed using combined native and invaded range distributional information provided better habitat suitability predictions in the invaded ranges. Efforts were also made to identify the suitable niches of this invasive species globally. The current global model was projected onto two future periods (2041–2070 and 2071–2100) under two different emission scenarios (SSP126 and SSP585). Our study highlights four important features related to the ecological niches of Argentine ants: (1) large habitat preference towards permanent streams in the native ranges, (2) native ecological niche is only partly conserved across invaded ranges, (3) invaded range niches are largely differentiated, and (4) global warming induces an increase in habitat suitability in the northern hemisphere. The results of this study may provide potential insights for the effective implementation of management strategies.

When introduced species hybridize with native relatives, spread of advantageous invasive genes into native populations (introgression) is a conservation concern. Genome-scale SNP (single nucleotide polymorphism) analysis can be a powerful approach to detect hybridization and identify candidate loci experiencing selection in hybrid zones. However, followup studies are critical to verify and interpret potentially impactful patterns of introgression. In an earlier publication we identified three outlier loci (out of 68 unlinked SNPs) where non-native alleles appeared to have introgressed 90 km into the range of a threatened native salamander, while the other 65 markers showed no evidence of spread further than 12 km. This was consistent with strong selection favoring a few invasive traits, but our inferences necessarily depended on limited reference samples of the native species. Here, we further tested our initial interpretation by interrogating the outlier markers in greater detail. First, we isolated DNA from two museum specimens of native salamanders collected several decades before the introduction. Both had the putatively invasive SNPs, indicating that the SNP alleles were present before the introduction and therefore not diagnostic for nonnative ancestry. Second, we developed a novel genealogical analysis of DNA sequences (rather than SNPs) to infer allelic ancestry, since genealogical analysis of haplotypes minimizes the ancestry assignment errors that can occur with SNPs. When applied to the original loci, this analysis confirmed that the genotypes formerly interpreted as ‘superinvasive’ are native variants, and non-native alleles remain limited to areas near the original introduction sites.

The abundance of an invasive species within an ecosystem after introduction can depend on multiple factors. Although large-scale abiotic data are typically used to model the distribution of invasive species, there may be other fine-scale environmental or biotic factors within the invaded range influencing changes in the species’ distribution and abundance. Here, we examined the abundance of the invasive tropical/subtropical green porcelain crab, Petrolisthes armatus (Gibbes, 1850), at 33 oyster reef sites along 150 km of coastline within the northerly portion of its invaded range. We measured a suite of biological, physical, and landscape level metrics to examine which factors (other than temperature) were most associated with the abundance of this invasive species. P. armatus were present at 32 reefs across our spatial range and densities were highest at the northern sites in our domain. Our results revealed native mud crab density is positively correlated with P. armatus density, accounting for 23% of the spatial variation in abundance of P. armatus within its invaded range, more than 30 years after initial invasion. We hypothesize that the positive associations between native predatory mud crabs and this invasive crab may be a result of hydrodynamics aggregating both species within the same areas, or attraction by both crabs for the same fine-scale habitat structural attributes (i.e., interstitial space). These data emphasize the importance of collecting high-resolution survey data to understand the variables that are correlated with the abundance and distribution of invasive species at regional scales within its invaded range.