Introduction Of Non-native Species Research Articles

Half of global islands have reached critical area thresholds for undergoing rapid increases in biological invasions.

Biological invasions are among the threats to global biodiversity and social sustainability, especially on islands. Identifying the threshold of area at which non-native species begin to increase abruptly is crucial for early prevention strategies. The small-island effect (SIE) was proposed to quantify the nonlinear relationship between native species richness and area but has not yet been applied to non-native species and thus to predict the key breakpoints at which established non-native species start to increase rapidly. Based on an extensive global dataset, including 769 species of non-native birds, mammals, amphibians and reptiles established on 4277 islands across 54 archipelagos, we detected a high prevalence of SIEs across 66.7% of archipelagos. Approximately 50% of islands have reached the threshold area and thus may be undergoing a rapid increase in biological invasions. SIEs were more likely to occur in those archipelagos with more non-native species introduction events, more established historical non-native species, lower habitat diversity and larger archipelago area range. Our findings may have important implications not only for targeted surveillance of biological invasions on global islands but also for predicting the responses of both non-native and native species to ongoing habitat fragmentation under sustained land-use modification and climate change.

Assessing the role of non-native species and artificial water bodies on the trophic and functional niche of Mediterranean freshwater fish communities

Habitat alterations and the introduction of non-native species have many ecological impacts, including the loss of biodiversity and a deterioration of ecosystem functioning. The effects of these combined stressors on the community trophic web and functional niche are, however, not completely clear. Here, we investigated how artificial ecosystems (i.e. reservoirs) and non-native species may influence the trophic and functional niche space of freshwater fish communities. To do so, we used carbon and nitrogen stable isotope and abundance data to compute a set of isotopic, trait, and functional metrics for 13 fish communities sampled from 12 distinct ecosystems in Türkiye. We show that in reservoirs, fish were more similar in their trophic niche compared to lakes, where the trophic niche was more variable, due to higher habitat complexity. However, there were no differences in the trait and functional metrics between the two ecosystem types, suggesting a higher prey diversity than assumed in reservoirs. We also found that the number of non-native species did not affect the trophic niche space, nor the trait or functional space occupied by the fish community. This indicates that non-native species tended to overlap their trophic niche with native species, while occupying empty functional niches in the recipient community functional space. Similarly, the proportion of non-native species did not affect any trophic, trait, or functional metric, suggesting that changes in community composition were not reflected in changes in the community niche space. Moreover, we found that trait richness, but not functional richness, was positively related to the isotopic niche width and diversity, indicating that a wider occupied trait niche space corresponded with a wider occupied trophic niche and lesser interspecific similarity. Our findings underscore the complexity of ecological relationships within freshwater ecosystems and highlight the need for comprehensive management strategies to mitigate the impacts of human activities and biological invasions.

Anthropogenic Eutrophication Drives Major Food Web Changes in Mwanza Gulf, Lake Victoria

Discerning ecosystem change and food web dynamics underlying anthropogenic eutrophication and the introduction of non-native species is necessary for ensuring the long-term sustainability of fisheries and lake biodiversity. Previous studies of eutrophication in Lake Victoria, eastern Africa, have focused on the loss of endemic fish biodiversity over the past several decades, but changes in the plankton communities over this same time remain unclear. To fill this gap, we examined sediment cores from a eutrophic embayment, Mwanza Gulf, to determine the timing and magnitude of changes in the phytoplankton and zooplankton assemblages over the past century. Biogeochemical proxies indicate nutrient enrichment began around ~ 1920 CE and led to rapid increases in primary production, and our analysis of photosynthetic pigments revealed three zones: pre-eutrophication (prior to 1920 CE), onset of eutrophication with increases in all pigments (1920–1990 CE), and sustained eutrophication with cyanobacterial dominance (1990 CE–present). Cladoceran remains indicate an abrupt decline in biomass in ~ 1960 CE, in response to the cumulative effects of eutrophication and lake-level rise, preceding the collapse of haplochromine cichlids in the 1980s. Alona and Chydorus, typically benthic littoral taxa, have remained at relatively low abundances since the 1960s, whereas the abundance of Bosmina, typically a planktonic taxon, increased in the 1990s concurrently with the biomass recovery of haplochromine cichlid fishes. Overall, our results demonstrate substantial changes over the past century in the biomass structure and taxonomic composition of Mwanza Gulf phytoplankton and zooplankton communities, providing a historical food web perspective that can help understand the recent changes and inform future resource management decisions in the Lake Victoria ecosystem.

A Report on the Accidental Introduction of Asian House Gecko (<i>Hemidactylus frenatus</i> Duméril et Bibron, 1836) into the Heuksan Island of South Korea

Recently, as trade between countries has flourished, the sale of living creatures has become more active. In this process, whether intentional or not, the introduction of non-native species is increasing as well. When non-native species are intentionally introduced, the route is evident which enables swift management. However, when accidentally introduced, the management of non-native species is difficult, because the route of the introduction is unclear. In this paper, we report a non-native species introduced into a small island in South Korea. On July 17, 2020, a gecko species was found on Heuksan Island. Based on its external traits, the gecko was identified as Hemidactylus frenatus, one of the rapidly increasing invasive species in the world. The gecko was dead in a packed box upon discovery, 88 km from the nearest port, and about 320 km from Seoul, where the package was shipped from. This case is yet another evidence of how non-native species can be introduced to other countries and even islands.

A global analysis of the introduction pathways and characteristics associated with non-native fish species introduction, establishment, and impacts

BackgroundThe invasion success of introduced freshwater fishes is influenced by many factors, including ecological, species, and socioeconomic characteristics. Most studies that document the importance of these characteristics are conducted at local scales and/or focus on a single step of the invasion process. In this study, we aim to determine the species characteristics, ecological characteristics, and socioeconomic characteristics of non-native freshwater fish invasions. Our assessment was done at the global scale and considers all three steps of the invasion (i.e., introduction, establishment, and impact). For this purpose, we applied generalized linear models to 20 variables collected for 307 non-native species and modeled them as a function of ecological characteristics (i.e., environmental features), species traits (i.e., functional and morphological), and socioeconomic characteristics (i.e., human use and introduction pathways). We considered the number of countries in which each species was introduced, established, or had ecological impacts as a proxy of invasion step success. We also explored the specifics of species introduced through the aquaculture and the ornamental fish trade pathways.ResultsWe found that non-native freshwater fishes with broad diets, high parental care, and multiple introduction pathways are the most widely introduced and established worldwide. The number of countries with impacts reported was best explained by the type of introduction pathway (i.e., aquaculture or fisheries). Moreover, among non-native species introduced through aquaculture, those belonging to Cypriniformes and having broad diets were the most widely introduced and established species. In contrast, the species introduced through the ornamental fish trade pathway belonged to various taxonomic orders but were mainly native to tropical regions.ConclusionsConsidering several types of factors is important when analyzing the invasion success of freshwater fish and disentangling the different invasion steps. These findings have strong implications for anticipating the profile of species with a high potential to invade many countries.

Live‐bait industry as a pathway for movement of nonnative and invasive species: Implications for conservation of native Texas fishes

AbstractObjectiveLive‐bait species are widely used in recreational fishing throughout the United States. However, the use of invasive fish species as live bait has been identified as a common pathway for their introduction into aquatic ecosystems. We assessed the role that the live‐bait industry has in facilitating the introduction of nonnative and invasive species into Texas rivers. We focused on two invasive cyprinodontid species, the Sheepshead Minnow Cyprinodon variegatus and Gulf Killifish Fundulus grandis, which are believed to have been introduced into inland Texas rivers via bait‐bucket releases by anglers.MethodsWe conducted telephone and in‐person surveys of live‐bait shops in Texas on a seasonal basis (summer, fall, winter, spring) for 1 year. Locally owned bait shops and regional aquaculture facilities and hatcheries were included in the surveys.ResultSurveys did not reveal the presence of these invasive cyprinodontids in inland bait shops but did reveal the sale of nonnative Goldfish Carassius auratus and their black color morph, the black salty goldfish. Surveys conducted among inland and coastal live bait shops confirmed the sale of only one nonnative bait fish and six bait items native only to certain regions of Texas. Telephone surveys with aquaculture industry experts revealed that the aquaculture industry was also facilitating the movement of nonnative game and nongame fish species throughout the state.ConclusionGiven the potential for nonnative and invasive species to negatively affect recipient aquatic ecosystems, the continued distribution of such species within the aquaculture industry represents a potential threat in Texas. Our findings highlight the need for close monitoring of the live‐bait industry in the state to prevent further introductions into inland waters and reduce potential ecological risks to native fish populations and overall ecosystem functions and services.

Irrigation dams threaten Brazilian biodiversity.

Brazil is among the main contributors to global biodiversity, which, in turn, provides extensive ecosystem services. Agriculture is an activity that benefits greatly from these ecosystem services, but at the same time is degrading aquatic and terrestrial ecosystems and eroding Brazilian biodiversity. This conflict is growing, as emerging unsustainable legislative proposals that will benefit the agricultural sector are likely to accelerate the decline of biodiversity. One such initiative (Bill 1282/2019) would change Brazil's "Forest Code" (Law 12,651/2012) to facilitate construction of irrigation dams in Permanent Preservation Areas, a category that includes strips (with or without vegetation) along the edges of watercourses. Two other similar bills are advancing through committees in the Chamber of Deputies. Here we provide details of these three bills and discuss their consequences for Brazil's biodiversity if they are approved. Expected negative impacts with changes in the legislation include: increased deforestation; siltation; habitat fragmentation; introduction of non-native species; reduction in the availability of aquatic habitats; and changes in biogeochemical process. These proposals jeopardize biodiversity and may compromise the negotiations for an agreement between Mercosur and the European Union.

Non-native fish species as an important part of Zambia's food system: a case study of the Lake Kariba fishery

Fish have an important role in food systems of Zambia and are a cheaper source of animal protein, vitamins and minerals. Presently, fish catches are dwindling and many children and women in rural Zambia are malnourished because their diet consists mainly of maize, vegetables and legumes. The main component of the diet is nsima, a form of thick porridge prepared from maize flour, which provides energy as carbohydrates. This study was done to assess the impact of a non-native fish species (Oreochromis niloticus, Nile tilapia) which has both positive and negative impacts on Zambia’s food system, with particular reference to the Lake Kariba fishery. The study was based on a networked systems framework, achieved through the administration of questionnaires, interviewing 377 randomly selected respondents from the three areas of the lake (I, II and IV) and 156 respondents from 7 selected open fish markets. Focus group discussions (FGD) were done with women, men and youth, who were key informants. Analysis of results using chi-square analysis, which cross-tabulated variables were used to obtain the results. Non-native fish were introduced in the early 1980s for cage culture production in Lake Kariba but some fish accidentally escaped. This has changed the composition and abundance of fish species in the lake. Despite the negative ecological impact on native biodiversity, results showed that more fish are available to households, improving nutrition and disposable income from fish sales. The disposable income is used to purchase other foods, thereby reducing malnutrition among rural households. Thus, the introduction of appropriate non-native species might benefit households and the nation as a whole. Key words: Malnutrition, non-native fish species, Lake Kariba, Zambia, tilapia, Oreochromis niloticus

Trophic niche partitioning among non-native fish species coexisting in a Colombian high Andean reservoir

The introduction of non-native species to a new environment poses a threat to local biological diversity, causing instability in the functioning of the ecosystem. The ecological effects caused by these species have been scarcely documented in the Magdalena basin. By studying predator–prey interactions, we characterized the trophic niche of three non-native species (Cyprinus carpio, Micropterus salmoides, and Oncorhynchus mykiss) that dominate a high Andean reservoir in the Magdalena basin. This study allows us to understand their specific feeding behaviors and how these behaviors facilitate their establishment in the reservoir. We evaluated the diversity of the prey they consume, their feeding strategy, and possible differences in the feeding scheme. Forty individuals were analyzed, with the highest representation of M. salmoides with 17 individuals, followed by C. carpio (13 individuals), and finally O. mykiss with 10 individuals. We identified twenty categories of food as prey for these species, with aquatic invertebrates and vegetation material being the predominant prey. The analysis of stomach contents in these samples suggested that they are representative for determining specialized or generalist feeding strategies. There were no differences in the number of prey items consumed by these three species. The analysis revealed that the feeding strategies are specific for each species. There was no overlap in the diet of C. carpio with the other two species, however, the composition of the diet is similar between M. salmoides and O. mykiss. Analyzing the diet of these non-native fish provides a useful tool for describing trophic interactions in this aquatic environment. Our results contribute information on the existing interactions amongst non-native species in the Magdalena basin, which is important for the development of strategies to manage and mitigate their impact.

Past and recent anthropogenic pressures drive rapid changes in riverine fish communities

Understanding how and why local communities change is a pressing task for conservation, especially in freshwater systems. It remains challenging because of the complexity of biodiversity changes, driven by the spatio-temporal heterogeneity of human pressures. Using a compilation of riverine fish community time series (93% between 1993 and 2019) across the Palaearctic, Nearctic and Australasia realms, we assessed how past and recent anthropogenic pressures drive community changes across both space and time. We found evidence of rapid changes in community composition of 30% per decade characterized by important changes in the dominant species, together with a 13% increase in total abundance per decade and a 7% increase in species richness per decade. The spatial heterogeneity in these trends could be traced back to the strength and timing of anthropogenic pressures and was mainly mediated by non-native species introductions. Specifically, we demonstrate that the negative effects of anthropogenic pressures on species richness and total abundance were compensated over time by the establishment of non-native species, a pattern consistent with previously reported biotic homogenization at the global scale. Overall, our study suggests that accounting for the complexity of community changes and its drivers is a crucial step to reach global conservation goals.

Economic costs of invasive non-native species in urban areas: An underexplored financial drain

Urbanization is an important driver of global change associated with a set of environmental modifications that affect the introduction and distribution of invasive non-native species (species with populations transported by humans beyond their natural biogeographic range that established and are spreading in their introduced range; hereafter, invasive species). These species are recognized as a cause of large ecological and economic losses. Nevertheless, the economic impacts of these species in urban areas are still poorly understood. Here we present a synthesis of the reported economic costs of invasive species in urban areas using the global InvaCost database, and demonstrate that costs are likely underestimated. Sixty-one invasive species have been reported to cause a cumulative cost of US$ 326.7 billion in urban areas between 1965 and 2021 globally (average annual cost of US$ 5.7 billion). Class Insecta was responsible for >99 % of reported costs (US$ 324.4 billion), followed by Aves (US$ 1.4 billion), and Magnoliopsida (US$ 494 million). The reported costs were highly uneven with the sum of the five costliest species representing 80 % of reported costs. Most reported costs were a result of damage (77.3 %), principally impacting public and social welfare (77.9 %) and authorities-stakeholders (20.7 %), and were almost entirely in terrestrial environments (99.9 %). We found costs reported for 24 countries. Yet, there are 73 additional countries with no reported costs, but with occurrences of invasive species that have reported costs in other countries. Although covering a relatively small area of the Earth's surface, urban areas represent about 15 % of the total reported costs attributed to invasive species. These results highlight the conservative nature of the estimates and impacts, revealing important biases present in the evaluation and publication of reported data on costs. We emphasize the urgent need for more focused assessments of invasive species' economic impacts in urban areas.

Increasing fish biodiversity in high elevation Albertan lakes in response to global environmental change over the past 50 years

IntroductionThe diversity of freshwater fishes is threatened by multiple environmental stressors, including climate change, alterations in land use, and introduction of non-native species. However, the quantification of temporal biodiversity in freshwater communities is limited. Here, we asked: i) how has alpha (species richness), beta (changes in freshwater species composition), and gamma diversity (total species diversity in a landscape) changed over time for lakes over a 50 year period?; and ii) What are the climatic, land use, and lake morphological drivers associated with higher diversity?MethodsWe assembled a database of fish species occurrence from 20 lakes across subalpine and alpine regions in Alberta from 1970-2019, in addition to lake morphological, climatic, and land use characteristics of the watersheds. ResultsWe observed an overall increase in alpha, beta, and gamma diversity from the 1970s to 2009s. However, all measures of diversity declined from 2010-2019. We found that more lakes and species assemblages were influenced by species gains, rather than species losses (with the exception of the last decade of sampling). DiscussionGenerally, we found that coolwater species were expanding and coldwater fishes were being lost throughout our study lakes. We highlight temporal heterogeneity in fish biodiversity responses to substantial environmental pressures in this region.

Floristic homogenization of South Pacific islands commenced with human arrival

The increasing similarity of plant species composition among distinct areas is leading to the homogenization of ecosystems globally. Human actions such as ecosystem modification, the introduction of non-native plant species and the extinction or extirpation of endemic and native plant species are considered the main drivers of this trend. However, little is known about when floristic homogenization began or about pre-human patterns of floristic similarity. Here we investigate vegetation trends during the past 5,000 years across the tropical, sub-tropical and warm temperate South Pacific using fossil pollen records from 15 sites on 13 islands within the biogeographical realm of Oceania. The site comparisons show that floristic homogenization has increased over the past 5,000 years. Pairwise Bray–Curtis similarity results also show that when two islands were settled by people in a given time interval, their floristic similarity is greater than when one or neither of the islands were settled. Importantly, higher elevation sites, which are less likely to have experienced human impacts, tended to show less floristic homogenization. While biotic homogenization is often referred to as a contemporary issue, we have identified a much earlier trend, likely driven by human colonization of the islands and subsequent impacts.

An Influx of Non-Native Bird Species into the Natural Environment Owing to the Accidental Release of Pet Birds in Japan.

The escape of pet birds into the wild raises concerns about the introduction of invasive avian species. This study investigated the impact of escaped pet birds on the introduction of non-native species in Japan. Data sourced from four lost-and-found pet websites between January 2018 and December 2021 revealed 12,125 recorded escapes exhibiting both daily occurrences and seasonal fluctuations. Statistical modeling identified the monthly average temperature (positively correlated) and maximum electricity demand (negatively correlated) as influential factors. Text analysis revealed "window" and "open" as frequently cited reasons for escapes. Budgerigars (Melopsittacus undulatus) and Cockatiels (Nymphicus hollandicus) accounted for 76% of the total escape, suggesting a low perceived risk of establishment in nonnative environments. Interestingly, two globally established invasive species, the Rose-ringed Parakeet (Psittacula krameri) and Monk Parakeet (Myiopsitta monachus), were among the escaped birds. While the Rose-ringed Parakeet is locally naturalized in Tokyo and its adjacent prefectures, the Monk Parakeet failed to establish itself in Japan. Despite the limited number of escaped Monk Parakeets, ongoing efforts are crucial for preventing the potential re-establishment of species with such capabilities.

Invasive Alien Plant Species on Hiking Trails in Mount Prau, Indonesia

Hiking tourism activities create habitats that support the introduction of non-native (alien) plant species and encourage their further spread in mountainous areas. Consequently, this will change the species composition of mountain plant communities. This research aims to investigate the richness of plant species and examine alien plant species that have the potential to be invasive on one of the mountains that is popular as a tourist destination, namely Mount Prau, Indonesia. Plant data collection was carried out using exploration methods according to hiking routes. PAST statistical software was used to carry out cluster analysis based on the composition of the plant community species and the composition of invasive alien species. The results of exploration on several hiking routes on Mount Prau found 192 species of plants. A total of 22 species are known to be invasive alien plants dominated by the Asteraceae family. Traditional hiking routes have a higher species richness value than commercial hiking routes for nature tourism. The research results also strengthen predictions that hiking routes for tourism activities have potentially increased the presence of invasive alien species of plants in mountainous areas.

Preserving Uruguay’s freshwater systems: the need to restrict invasive species introductions for sustainable production

This manuscript critically examines the history of non-native aquatic species introductions in Uruguay, emphasizing the role of public institutions. Despite global concerns about biodiversity threats from these introductions, Uruguay’s reliance on animal production and aquaculture involving non-native species has grown since the 1980s. State institutions, despite past failures, have promoted these introductions without comprehensive risk assessments. Notable cases, including failed attempts with species like the herbivorous carp, American bullfrog, Nile tilapia, Australian redclaw crayfish, and American mink, raise concerns about invasive populations due to a lack of proper risk assessments and prevention measures. Previous examples were deficient in escape monitoring, oversight of specimens after farm closures, and considerations for the presence of new pathogens. This highlights the need for more informed and responsible approaches to prevent invasive species’ establishment, advocating for rigorous analysis and risk assessments before any introduction. We propose overcoming historically fragmented decision-making processes by establishing a bridging structure that coordinates inter- and intra-institutional efforts, engages with the academic sector and social organizations, and evaluates the introductions. This platform can prioritize protecting aquatic ecosystems, fostering sustainable growth, and maintaining ecological balance, contributing to the solution of the problem by facilitating coordinated efforts and engaging diverse stakeholders.

Examining the Effects of Bio Fouling on Ships and How It Contributes to the Introduction of Non-native Species in Newly Discovered Coastal Areas in Bio Fouling on Ship Hulls and Its Ecological Ramification

Examining the Effects of Bio Fouling on Ships and How It Contributes to the Introduction of Non-native Species in Newly Discovered Coastal Areas in Bio Fouling on Ship Hulls and Its Ecological Ramification

Insights into the ecological impact of trout introduction in an oligotrophic lake using sedimentary environmental DNA

Introduced trout can induce trophic cascades, however, a lack of pre-introduction data limits knowledge on their impact in many lakes. Traditional paleolimnological approaches have been used to study historic species changes, but until recently these have been restricted to taxa with preservable body-parts. To explore the ecosystem effects of Salmo trutta (brown trout) introduction on an oligotrophic lake in Aotearoa-New Zealand, we used a multi-marker sedimentary environmental DNA (sedDNA) approach coupled with pigments to detect changes across multiple trophic levels. DNA was extracted from core depths capturing approximately 100 years before and after the expected arrival of S. trutta, and metabarcoding was undertaken with four primer sets targeting the 12S rRNA (fish), 18S rRNA (eukaryotes) and cytochrome c oxidase (COI; eukaryotes) genes. The earliest detection of S. trutta eDNA was 1906 (1892–1919 CE with 95% high probability density function) suggesting their introduction was shortly before this. Native fish diversity (12S and 18S rRNA) decreased after the detection of S. trutta, albeit the data was patchy. A shift in overall eukaryotic and algal communities (18S rRNA and COI) was observed around 1856 (1841–1871 CE) to 1891 (1877–1904 CE), which aligns with the expected S. trutta introduction. However, taxonomy could not be assigned to many of the 18S rRNA and COI sequences. Pigment concentrations did not change markedly after S. trutta introduction. SedDNA provides a new tool for understanding the impact of disturbances such as the introduction of non-native species; however, there are still several methodological challenges to overcome.

Distribution of invasive Procambarus clarkii (Girard, 1852) (Decapoda: Astacidea: Cambaridae) in South Korea, with a study of the spatial variation of benthic macroinvertebrate taxa

Abstract The introduction and spread of non-native species pose major threats to biodiversity and ecosystem stability. We conducted a study to assess the spread, growth rate, and interactions of the exotic crayfish Procambarus clarkii (Girard, 1852) throughout South Korea. A total of 343 individuals (223 from reservoirs, 120 from streams) were studied in four provinces. This species has expanded its distribution to 24 regions in South Korea. The length-weight relationship indicated positive allometric growth, expressed as W = 2.855L3.0073. The highest number of adult P. clarkii individuals eradicated was 11,438 in 2022. Using the MaxEnt model and environmental variables related to the climate, a highly accurate forecast was generated for the potential distribution of P. clarkii in South Korea. The factors influencing the current distribution probability were identified as the highest temperature of the warmest month, mean temperature of the wettest quarter, and mean temperature of the warmest quarter, which contributed the most to the present distribution probability. The predicted distribution indicated a rapid increase in P. clarkii density in the southwestern region, extending towards the southeastern and central regions, including the brackish zone. Non-metric multidimensional scaling analysis (stress = 0.07) was conducted based on benthic macroinvertebrates, revealing distinct variations among the four sampling sites. The distribution of benthic macroinvertebrates was significantly influenced by the proportion of sand in the substrate (R = 0.39, P < 0.05) and water quality as estimated by the electrical conductivity (R = 0.51, P < 0.05).

Simultaneous detections of Olenecamptus bilobus (Fabricius, 1801) (Cerambycidae, Dorcaschematini) in Europe

Europe has a long history of non-native species introductions given its central role in global trade in recent centuries. Currently, approximately two hundred cerambycid species have been found in Europe, as the result of introductions between and within biogeographical regions; still, despite better monitoring and stronger restrictions, the arrivals and spread of non-native Cerambycidae continue. The aim of this contribution is to report and discuss the first European records of the non-native longhorn beetle Olenecamptus bilobus (Fabricius, 1801) on the basis of three specimens recorded almost simultaneously in Spain and Greece, respectively.