Introduction Of Exotic Species Research Articles

Cage farming in the environmental mix of Lake Victoria: An analysis of its status, potential environmental and ecological effects, and a call for sustainability

AbstractLake Victoria is the second largest freshwater lake in the world that was once a biodiversity hotspot hosting over 500 endemic haplochromine cichlids that were later decimated by exotic introductions and anthropogenically driven environmental and ecological changes. The environmental and ecological changes in the lake over the years have been attributed to overfishing, eutrophication, introduction of exotic species, pollution and possibly climate change. The lake's capture fishery, which is the main economic activity directly and indirectly supporting over 40 million people, has continued to decline after experiencing a boom between the 1970s and 1990s following the introduction of Nile Perch (Lates niloticus) and Nile Tilapia (Oreochromis niloticus). In order to augment capture fisheries from the lake, cage culture was introduced in 2005, but its sustainability and influence on the ecology of the lake are not well understood. In this review, we examine the genesis of degradation of Lake Victoria and assess the role of cage culture as both a solution to the current situation and a cause for concern for the ecology of the lake. To compile this review, we utilized data in the grey and published literature. Studies show that the degradation of the lake can be traced back to the 1930s when the trophic status and ecology of the lake started showing signs of anthropogenic influence. The Nile Perch was introduced in early 1960s to replenish the fishery but its ecological impacts were felt in 1970s and 1980s when the native haplochromine species started to disappear from catches. Progressively, the ecological changes and management concerns in the lake have become a complex mix of exotic species introductions, eutrophication, and overfishing. In this mix of persistent ecological changes, the once thriving capture fisheries revolving around the two exotic species (L. niloticus and O. niloticus) have significantly declined threatening the livelihoods of millions of people directly and indirectly involved in the fisheries. These declines necessitated the introduction of cage culture in 2005 to fill the increasing demand for fish from the lake. Ever since, cage numbers have increased tremendously (>6 000 by 2020) and is now operated by over 60 different firms which are owned either individually or by groups. Over 70% of the cages have been installed in shallow areas within the Winam Gulf which goes against the guidelines on cage installation and operation; regulations on cage farming were introduced after the activity had gained momentum in the lake. Limnological data in areas of the lake that have been stocked with cages has shown evidence of negative effects on water quality. This decline in water quality can be attributed to remnant feeds used in cages, of which 50% are the sinking types, and wastes from fish excretion and egestion. Although data are limited, the potential influence of cage farming on the already altered ecology and environment of Lake Victoria needs to be recognized and investigated. This study recommends studies targeting operations of cages in the lake, including a comprehensive environmental audit to inform their sustainability and relevant policy.

Novel food resources and conservation of ecological interactions between the Andean Araucaria and the Austral parakeet.

In fragile ecosystems, the introduction of exotic species could alter some ecological processes. The Austral parakeet (Enicognathus ferrugineous) shows close ecological and evolutionary relationships with the Andean Araucaria (Araucaria araucana), so any alteration in these interactions may have negative consequences for both partners and for ecosystem functioning and structure. We conducted extensive roadside surveys to estimate the abundance of parakeets in the northern Patagonian Andes over 4 years and recorded the food plants consumed by foraging flocks. The use of native habitats and humanized areas like villages and farms was influenced by the Araucaria seed crop. In masting years, the large seed crop allowed a massive use of this resource during the non‐breeding season, and even during the breeding season. The exploitation of exotic plants was minor in the masting year, but became predominant in non‐masting years, especially during the non‐breeding season. This feeding switch towards exotic plants primarily arose because the low Araucaria seed crop in non‐masting years is entirely consumed just after production by domestic and wild exotic mammals living in Araucaria forests year‐round, thus forcing the displacement of parakeets towards anthropic habitats to exploit exotic plants. Given the degradation of the remaining Andean Araucaria forests due to the impact of exotic mammals on the ecological interaction between Araucaria and Austral parakeets, ambitious programs to exclude or reduce the density of these alien mammals, including livestock, are warranted.

Spatio-temporal dynamics of exotic fish species in the Mediterranean Sea: Over a century of invasion reconstructed.

With over a thousand of introduced species, the Mediterranean is the most heavily invaded marine region in the world. Yet, the spatio-temporal dynamics of this bioinvasion has never been analysed. Examination of a comprehensive dataset of 4015 georeferenced observations, extracted from the scientific literature, allowed (i) reconstructing the invasion and the introduction and post-introduction dynamics of exotic fish species, (ii) calculating introduction and spread rates, and (iii) investigating the time correlates since introduction. Our analysis encompasses 188 fish species that entered the Mediterranean from 1896 to 2020, including 25 Atlantic species that naturally expanded their range through the Strait of Gibraltar. Cumulative occurrences, reported in 264 distribution maps, documented the progressive expansion of the most represented species and the spatio-temporal patterns associated with three introduction routes: the Suez Canal (CAN); other human-mediated vectors (HM) and the Strait of Gibraltar (NRE). The arrival rate of the species introduced through all three routes increased steeply after 1990, without a sign of saturation. Data analysis highlighted some temporal and geographical patterns, such as the effect and eventual weakening of the biogeographical barriers represented by the Strait of Sicily and the North Aegean Sea and the asymmetrical distribution of occurrences along the northern and southern Mediterranean coasts. Finally, there was an exponential increase in the secondary spread rates of CAN and NRE immigrants, as the more recent introductions achieved the fastest geographical expansions. Our findings provide a detailed and spatially explicit summary of a massive invasion that has changed the history of the Mediterranean biota and represent a remarkable example of rapid biotic homogenization in the global ocean.

Status of the zooplankton ecology in freshwater ecosystems from Argentina

In this contribution, we reviewed ecological studies on zooplankton that were carried out in freshwater systems of Argentina. The diversity of landscapes of the country hosts a great variety of freshwater systems, from large rivers to shallow and deep lakes. We divided Argentina into five different regions: 1- shallow lakes and streams and rivers of the pampas, 2- potamoplankton of great rivers and shallow lakes of the northeast, 3- west and northwest lakes, 4- Patagonian Plateau lakes, and 5- Deep glacial lakes of the Patagonian Andes. Our review showed that there are contributions of almost all modern aspects of zooplankton ecology: herbivory, predation, nutrient recycling, trophic cascade, ecological stoichiometry. Researchers were also able to identify the most important factors, and different threats affecting ecological processes related to zooplankton in each region. However, these aspects are not evenly developed in all regions, as the region of West and northwest lakes has been less studied as almost all topics of zooplankton ecology need to be widened. Finally, we identified five topics that deserve further research including applied aspects like the effect of land use, climate change, exotic species introduction, connectivity and restoration practices.

Floristic homogenization as a result of the introduction of exotic species in China

AbstractAimThe introduction of exotic plants can both increase (homogenize) and decrease (differentiate) floristic similarity between areas. We have a poor understanding of the degree to which plant species introductions tend to homogenize or differentiate floras, and relevant studies covering large spatial extent are scarce. China has been heavily invaded by exotic plants. Here, we analyse a comprehensive dataset of vascular plants to determine whether the introduction of exotic plant species has homogenized or differentiated species composition in regions across China.LocationChina.MethodsWe calculated the Jaccard index and Simpson index of similarity for each pair of province‐level regions for native and exotic species separately and jointly, and calculated a homogenization index for each pair of regional floras. We correlated species richness of native and exotic plants to climatic factors, and correlated the Jaccard index and Simpson index to geographic and climatic distances. We used variation partitioning analysis to determine the relative importance of geographic and climatic distances on species turnover. We also examined the effect of human population density on florisitic similarity of exotic species.ResultsWe found that the geographic range of each species was, on average, larger for exotics than for natives; floristic similarity between regions was greater for exotics than for natives; the vast majority of pairwise regional floras have been homogenized; the introduction of exotic species has caused stronger biotic homogenization for pairwise floras with greater dissimilarity in their species composition; geographic distributions of exotic and native species were determined by different sets of climatic factors; and distributions of exotic species were determined by climatic factors more strongly, compared to those of native species. Human population density had a moderate effect on florisitic similarity of exotic species.Main conclusionsThe introduction of exotic plant species has homogenized regional floras across China. Because strong international trades between China and other countries and dramatic development of transportation systems are continuing in China, which help spread of exotic species, we predict that exotic species will continue to spread and will strengthen biotic homogenization in China.

The Bugs in the Bags: The Risk Associated with the Introduction of Small Quantities of Fruit and Plants by Airline Passengers.

Simple SummaryThis study was carried out with the aim of emphasizing the importance of checking the plant material that can be imported in the baggage of airline passengers. Travelers are often unaware of the regulations in place and of the risks connected with such importation. The risk of the introduction of harmful organisms correlated with this pathway is yet not well studied and its frequency is underestimated. The results of the research underline the need for continuous checks at entry points and the establishment of a specialized position for inspections.Among European countries, Italy is the most exposed to the risk of biological invasions, principally for its numerous entry points (ports and airports) and for climatic conditions favorable for the acclimatization of several invasive species. Here it was assessed that the greatest threats to our agro-ecosystems come mainly from the passenger baggage in which a variety of fruits and vegetables are carried. From 2016 to 2021, large quantities of plant products were found in the luggage of passengers travelling from outside the EU and seized at the BCPs (border control posts) in the Campania region. Inspections and the following laboratory analyses were conducted on the plant material to assess the presence of exotic pests. Inspections led to several non-native species being recorded, and among the intercepted organisms, some should be considered “alarming”, such as Bactrocera dorsalis, Anastrepha obliqua, and Leucinodes africensis. Despite a well-organized border inspection system, travelers transporting infested material unknowingly contribute to increasing the risk of the introduction of exotic species. Given the current situation, it is necessary to impose stricter controls and greater attention, ensuring compliance with the requirements of the new phytosanitary regulations by the actors involved in the transport of plant material. Finally, it is essential to improve awareness through a phytosanitary campaign on plant health risks, especially for people wishing to transport fruits and vegetables in their luggage.

Future Role of Exotic Tree Species in Hungarian Built Heritage Environments

Although some exotic tree species, new to the country at the time, had already been introduced at the turn of the 18th and 19th century in the Hungarian landscape gardens, using foreign tree species in the space composition became widely popular only from the second half of the 19th century. This research focused on determining the date of appearance and compositional role of exotic trees in Hungarian landscape gardens. We can still find aged exotic woody taxa which determine the historical spatial structure in numerous landscape gardens nowadays. The nationwide distribution of these species, and their location within the gardens, can be an important addition to the questions of the revitalization of historical gardens, the more so because they may be indicative of the climate adaptability and, therefore, resilience of built heritage environments. An experimental approach to the introduction and use of new exotic tree species in historic gardens where this approach can be proven to have existed is also discussed as an opportunity to use these gardens in search of new foreign taxa to adapt to climate change.

Predicting the Risk of Exotic Plant Invasions in the Orinoco Region: Importance of Distribution Models, Climatic Niche and Functional Richness

The process of biological invasions resulting from the introduction of exotic species is one of the most critical components of global environmental change. Although many hypotheses try to explain the processes underlying biological invasions, changes in land use are essential drivers mediating the colonization of exotic species at the landscape level. We used potential species distribution models developed in Maxent and a database of nine functional traits associated with invasion success for 18 exotic species with a high risk of establishment and difficulty of control in the Orinoco region from Colombia. We found that 67% of the species differed from the centroid in the climatic niche when comparing native and invaded localities. Overall, the native distribution localities showed a more restricted dispersal in their climatic niche, and for most species, native distribution was found within the broad environmental gradients of the invaded localities. Additionally, we found high climatic suitability for all exotic species across all the biomes and ecosystems; however, transformed ecosystems showed exotic plant species’ higher potential functional richness. Our research allowed us to identify key geographical areas that are highly susceptible to invasions and prioritize species that need control in particular ecosystems and biomes. This work provides early warnings on the potential risks of invasion of exotic species, and it will improve the monitoring and management efforts in the Orinoco region of Colombia.

Millipedes and centipedes (Myriapoda: Diplopoda, Chilopoda) in Swiss heated greenhouses, with seven species new for Switzerland

The international plant trade provides opportunities for the introduction of exotic species into tropical greenhouses around the world. The millipede and centipede fauna of greenhouses is barely known in Switzerland. We conducted a survey in greenhouses of nine botanical gardens and other institutions across Switzerland. We captured and identified 1390 individuals belonging to 14 millipede species and 43 individuals belonging to 9 centipede species. Most millipede individuals recorded (80.3%) were non-native as were the species (8/14). Most centipede individuals (55.3%) were non-native, but not the majority of the species (4/10). The species composition varied strongly among greenhouses with species originating from different parts of the world. Seven species already known from greenhouses in other European countries are reported for the first time in Switzerland. These are the millipedes Cylindrodesmus hirsutus Pocock, 1889, Poratia obliterata (Kraus, 1960), Paraspirobolus lucifugus (Gervais, 1836) and the centipedes Mecistocephalus guildingii Newport, 1843, Tygarrup javanicus Attems, 1929, Lamyctes (Lamyctes) coeculus (Brölemann, 1889b), and Cryptops (Cryptops) doriae Pocock, 1891. The relevance of these findings is discussed.

Coupling human and natural systems for sustainability: experience from China's Loess Plateau

Abstract. Addressing the sustainability challenges that humanity is facing in the Anthropocene requires the coupling of human and natural systems, rather than their separate treatment. To help understand the dynamics of a coupled human and natural system (CHANS) and support the design of policies and measures that promote sustainability, we propose a conceptual cascade framework of “pattern–process–service–sustainability”, which is characterized by coupling landscape patterns and ecological processes, linking ecological processes to ecosystem services, and promoting social–ecological sustainability. The use of this framework is illustrated by a review of CHANS research experience in China's Loess Plateau (LP), a well-known region for its historically severe soil erosion and successful ecological restoration achieved in recent decades. Ecological restoration in the LP has greatly increased its vegetation coverage and controlled its soil erosion. However, some accompanied issues, like soil drying in some areas due to the introduction of exotic plant species and the mismanagement of planted vegetation and water use conflicts between vegetation and humans caused by the trade-off between carbon sequestration and water supply, have started to threaten the long-term sustainability of the LP. Based on a comprehensive understanding of CHANS dynamics, the social–ecological sustainability of the LP can be improved through enhancing water and food security, implementing basin-wide governance, maintaining ecological restoration achievements, and promoting rural livelihood transition. The research experience accumulated on the LP offers examples of the application of the pattern–process–service–sustainability framework. Future research using this framework should especially focus on the integrated research of multiple processes; the cascades of ecosystem structure, function, services, and human well-being; the feedback mechanisms of human and natural systems; and the data and models for sustainability.

서울시 남산 신갈나무림 생태계 특성과 변화 연구

The purpose of this study is to secure objective and precise data through ecosystem monitoring, to reveal ecological characteristics through comparison and analysis with past survey data, and to accumulate basic data for diagnosing the current situation and predicting changes in the ecosystem. The target site is the ‘<italic>Quercus mongolica</italic> forest on the Buksa-myeon of Namsan’, which was designated as an Ecological Landscape Conservation Area (ELCA) of Seoul in July 2006. The research contents are analysis of soil environment change (1986~2016), change of actual vegetation (1978~2016), and change of plant community structure (1994~2016). A total of 8 fixed surveys (400∼1,200㎡) were established in 1994 and 2000. Analysis items are importance value, species and population, and Shannon’s species diversity. The soil environment of Namsan is acidic (pH 4.40 in 2016), which is expected to have a negative impact on tree growth and vegetation structure due to its low capacity for exchangeable cations. <italic>Quercus mongolica</italic> forest in Namsan is mainly distributed on the northern slopes. The actual vegetation area changed from 49.4% in 1978 → 80.7% in 1986 → 82.4% in 2000 → 88.3% in 2005 → 88.3% in 2009 → 70.3% in 2016. In 2016, the forest decreased by 18% compared to 2009. While there was increased growth of <italic>Quercus mongolica</italic> in the tree layer from 2009 to 2016, the overall decline in vegetation area was due to logging and fumigation management following the spread of oak wilt in 2012. As for the changes in the plant community structure, <italic>Quercus mongolica</italic> of the tree layer was damaged by oak wilt, and the potential vegetation that can form the next generation was ambiguous. In the subtree layer, the force of urbanization tree species such as <italic>Styrax japonicus</italic>, <italic>Sorbus alnifolia</italic>, and <italic>Acer palmatum</italic>. was maintained or increased. In the shrub layer, the number of trees and species increased significantly due to the open tree crown, and accordingly, the species diversity of Shannon for woody plants also increased. In <italic>Quercus mongolica</italic> forest of Namsan, various ecological changes are occurring due to the effects of urban environments such as air pollution and acid rain, the limitation of <italic>Quercus mongolica</italic> pure forest due to oak wilt, and the introduction of exotic species, thus, it is necessary to establish a management plan through continuous monitoring.

The monitoring of diet and habitat preferences indicates competitive effect of exotic Ictalurus nebulosus on native fish under food-limited conditions

Due to the increasing globalization and ongoing introduction of exotic species, native species are confronted with competitors with unknown outcomes. Catfish Ictalurus nebulosus Le Sueur, 1819 is native to eastern regions of North America. The species was introduced to some European countries, including Poland, in the 1880s for hobby and farming purposes, and it is currently present in freshwater bodies of almost the whole Europe. In this study, stomach content analyses were used to study food and habitat partitioning between catfish and native fish coexisting in a nutrient-poor lake. The results suggest strong competition between catfish and native perch, resulting in the dominance structure of fish untypical for nutrient-poor lakes. Moreover, catfish, which are opportunistic food generalists, displayed a very narrow food niche and selectively foraged on the most nutritional food items. This may suggest that the foraging opportunity of catfish undoubtedly supports the spreading of this species among various habitats, but catfish may become specialists when colonizing some ecosystems. In the context of the current expansion of catfish towards the eastern periphery of Europe, monitoring of its population sizes, trophic niches and effects on lower trophic levels are essential for the management and mitigation of its potential impacts on invaded freshwater ecosystems in Europe.

A predatory gastropod as the potential biological control agent of the Korean invasive mussel, Mytilus galloprovincialis (Lamarck, 1819)

The classical biological control, which is the intentional introduction of exotic species to manage the biological invasion, is the standard measure if the human-mediated management is no longer effective. This method, however, involves a latent risk that the introduced exotic species brings about the nontarget effect on indigenous native species. Applying the native natural predator is the best alternative to control the invasive alien species without the substantial change into the ecosystem of the area invaded. Here, we introduced an indigenous Korean muricid gastropod Reishia bronni (Dunker, 1860), a potential natural predator of the Mediterranean mussel Mytilus galloprovincialis (Lamarck, 1819), a well-known invasive alien species successfully settled down in Korea. In the biomonitoring survey on the Korean ports of the east coast between 2007 and 2011, we have observed the spread of R. bronni within the Mytilus galloprovincialis community. The observed decrease of the mussel density around the gastropod assemblage led us to the idea that R. bronni is the natural predator of M. galloprovincialis . In order to clarify such a predator-prey interaction between both species, we performed a field observation from two Korean ports in August 2012, keeping R. bronni and M. galloprovincialis individuals together into the cages for 18 days. Then, we counted the number of latter ones consumed and estimated the average time spent feeding per individual of R. bronni . We observed the positions of the drill holes made on the consumed shells by it. Our results showed that R. bronni is the active natural predator of M. galloprovincialis with the high feeding intensity and the unique foraging behavior targeting the lateral margin of the shell, so-called “Marginal drilling”. Therefore, we could suggest the possibility that R. bronni can be applied to control the mass spread of M. galloprovincialis .

Looking ahead, guided by the past: The role of U.S. national parks in amphibian research and conservation

Protected areas like national parks are essential elements of conservation because they limit human influence on the landscape, which protects biodiversity and ecosystem function. The role of national parks in conservation, however, often goes far beyond limiting human influence. The U.S. National Park Service and its system of land units contribute substantively to conservation by providing protected lands where researchers can document trends in species distributions and abundances, examine characteristics important for generating these trends, and identify and implement conservation strategies to preserve biodiversity. We reviewed the contribution of U.S. national parks to amphibian research and conservation and highlight important challenges and findings in several key areas. First, U.S. national parks were instrumental in providing strong support that amphibian declines were real and unlikely to be simply a consequence of habitat loss. Second, research in U.S. national parks provided evidence against certain hypothesized causes of decline, like UV-B radiation, and evidence for others, such as introduced species and disease. However, describing declines and identifying causes contributes to conservation only if it leads to management; importantly, U.S. national parks have implemented many conservation strategies and evaluated their effectiveness in recovering robust amphibian populations. Among these, removal of invasive species, especially fishes; conservation translocations; and habitat creation and enhancement stand out as examples of successful conservation strategies with broad applicability. Successful management for amphibians is additionally complicated by competing mandates and stakeholder interests; for example, past emphasis on increasing visitor enjoyment by introducing fish to formerly fishless lakes had devastating consequences for many amphibians. Other potential conflicts with amphibian conservation include increasing development, increased risk of introductions of disease and exotic species with increased visitation, and road mortality. Decision science and leveraging partnerships have proven to be key components of effective conservation under conflicting mandates in national parks. As resource managers grapple with large-scale drivers that are outside local control, public-private partnerships and adaptive strategies are increasing in importance. U.S. national parks have played an important role in many aspects of identifying and ameliorating the amphibian decline crisis and will continue to be essential for the conservation of amphibians in the future.

Alien vs. predator: influence of environmental variability and predation on the survival of ascidian recruits of a native and alien species

Drivers of successful introduction of exotic species remain a major headline in marine invasion biology. We ran two experiments aiming to disentangle the effects of abiotic factors like contaminants and the effect of predation on recruits’ survival of one native and one alien ascidian species. A feeding experiment allowed us to monitor microscale variation of generalist fish predation, which varied significantly within a marina. We also monitored the in situ survival of lab-grown ascidians at three locations within the marina, half with predator cage exclusion. The survival of the native Ciona intestinalis was conjointly highly influenced by location and caging. We were able to identify a link between predation intensity exerted by mobile generalist macropredators and C. intestinalis survival, whereas none of the measured contaminants accounted for site variability of survival. The non-indigenous Styela clava had significant higher survival and biomass when uncaged, suggesting a positive effect of predation for this species. The natural in situ recruits of C. intestinalis showed higher biomass when caged and may have competed with lab-grown S. clava. Our results suggest that generalist fish predation may play a crucial role in the success of non-indigenous species due to facilitation through competitive release.

New records of the occurrence of Megaleporinus macrocephalus () (Characiformes, Anostomidae) from the basins of the Itapecuru and Mearim rivers in Maranhão, Northeastern Brazil.

The "piaussu", Megaleporinus macrocephalus is an anostomatid fish species native to the basin of the Paraguay River, in the Pantanal biome of western Brazil. However, this species has now been recorded in a number of other drainages, including those of the upper Paraná, Uruguay, Jacuí, Doce, Mucuri, and Paraíba do Sulrivers. This study presents two new records of the occurrence of M. macrocephalus, in the basins of the Itapecuru and Mearim rivers in the state of Maranhão, in the Brazilian Northeast. The piaussu is a large-bodied fish of commercial interest that is widely raised on fish farms, and its occurrence in the Itapecuru and Mearim rivers is likely the result of individuals escaping from fish tanks when they overflow during the rainy season. Morphological analyses and sequences of the Cytochrome Oxidase Subunit I (COI) gene confirmed the taxonomic identification of the specimens as M. macrocephalus. The COI sequences were 99.66% similar to those of M. macrocephalus deposited in the BOLDSystems database. These records extend the known distribution of M. macrocephalus to the basins of the Itapecuru and Mearim rivers in the Brazilian Northeast, highlighting a new case of introduction of exotic fish species into Brazilian river basins.

O sol do meio-dia revela o que as águas escondem: Podocnemis unifilis Troschel, 1848 (Testudines, Podocnemididae), outra espécie exótica no Pantanal mato-grossense

Abstract The process of exotic species introduction is recognized as one of the greatest threats to the ecology and economy of the planet, due to changes in interactions in native biological communities. In this sense, reporting bioinvasions is the first step to understanding its introduction process and creating strategies to mitigate possible socio-environmental damages. Here we report the first records of Podocnemis unifilis introduced in the Northern Pantanal, Mato Grosso, Brazil. We obtained the species’ first records occasionally during 2014 and 2015. In the following years from 2016 to 2019, we carried out systematic observations through nautical incursions on the Paraguay River, between the Sepotuba River mouth and the Taiamã Ecological Station (TES). We also included third part records, when it was possible to prove the species identification and registration sites. Podocnemis unifilis adults, hatchling and nests were recorded at different points along the Paraguay River. Our results indicate that P. unifilis was introduced close to the urban nucleus of Cáceres about 30 years ago. Currently, it has an established population, recording nests and hatchling for years in a row. A particular one is its occurrence at the TES, an important natural fish nursery and refuge for the wetland fauna. Thus, continuous monitoring is suggested from P.unifilis, since the Pantanal’s environment with several different aquatic environments, offers favorable conditions for the species population increase in the Northern Pantanal.

Molecular identification of seed‐feeding flies dissected from herbarium specimens clarifies the 100‐year history of parasitism by Japanagromyza tokunagai in Japan

AbstractInsect pests, particularly seed‐feeding flies, can cause serious damage to the fruits of many wild orchid species. Evidence of fly damage has been observed in 55 orchid species, belonging to 25 genera, distributed throughout Japan. Although some authors suggested that the observed increase in fly damage to orchids in recent years is related to the introduction of exotic species, the timing and route of spread remain unclear. We examined herbarium specimens of seven orchid species, collected between 1923 and 2016, to collect coarctate pupae and empty puparia, with minimal damage to the specimens. Genomic DNA was then extracted from the insect tissue and species were identified using mitochondrial cytochrome oxidase subunit 1 barcode regions. Long amplicons (660 base pairs [bp]) were obtained from 45.2% of samples and short amplicons (162 bp) were obtained from 90.3% of samples. In total, 51 of 62 samples had nucleotide sequences homologous to Japanagromyza tokunagai, with specimens distributed across collection years and geographic locations. Therefore, the severe damage to Japanese orchids observed in recent years is not related to the recent introduction of an exotic species; it may be related to a rapid increase in a native species. This work highlights the value of herbaria as important resources for elucidating the history and distribution of parasitic insects.

Invasion and Dispersion of the Exotic Species Procambarus clarkii (Decapoda Cambaridae) in Yeongsan River Basin, South Korea.

Simple SummaryCurrently, the dispersion of the exotic species Procambarus clarkii in the Yeongsan River basin is a major issue in South Korea, where the majority of domestic crayfish occur in upstream river sections, while P. clarkii is mainly abundant in the middle and lower river reaches. In 2018, the species was initially observed only in the Jiseok Stream, a tributary stream of the Yeongsan River. Since then, the species has gradually dispersed in the Yeongsan River basin, and by 2021, the species was recorded in most of the main basin and tributary streams. The larvae of P. clarkii were abundant in areas with dense aquatic plants, whereas adults inhabited areas with silt/clay cover. However, P. clarkii appears to cause little impact on the freshwater ecosystem, despite its extensive dispersion. The species did not utilize native biological communities as food sources and is unlikely to be consumed by predators.The introduction of exotic species negatively affects the distribution and interactions within local biological communities in an ecosystem and can threaten ecosystem health. This study aimed to provide the basic data required to manage P. clarkii in the Yeongsan River basin. We identified the dispersion pattern and evaluated the ecosystem risk of this newly introduced species. The distribution survey investigated Procambarus clarkii populations at 25 sites in the Yeongsan River basin over a four-year period. The initial introduction occurred in Jiseok Stream. The larvae of P. clarkii were most abundant in areas with a dense aquatic plant cover, whereas adults preferred silt/clay areas. The alterations in the water flow by the river refurbishment project (carried out in 2012) increased their preferred habitats and contributed to P. clarkii dispersion. However, stable isotope analysis showed that the dispersion has had little effect on the freshwater ecosystem. The interrelationship between P. clarkii (i.e., larvae and adults) and other biological communities has been limited. Although the rapid dispersion by P. clarkii in the Yeongsan River basin has not impacted the freshwater ecosystem, further ecological information is required on how to manage P. clarkii beyond this early stage of invasion.

Review of threatened Malagasy freshwater fishes in zoos and aquaria: The necessity of an ex situ conservation network-A call for action.

Madagascar's biota is characterized by an extraordinary species richness, with a high degree of endemism. The island's freshwater habitats harbor numerous micro‐endemic species, restricted to particular regions and thus particularly at risk of extinction, due to deforestation, overfishing, and introduction of exotic species. The present study investigates for which threatened Malagasy freshwater fish species ex situ populations have already been established, as a baseline to prioritize actions to develop an effective ex situ conservation breeding network. Populations in zoos and aquaria were primarily determined using the Zoological Information System. Of 173 fish species recorded from Malagasy freshwater habitats, 123 exclusively inhabit freshwater; 79 of these are endemic to Madagascar, and 50 are classified as threatened. Our survey found 21 Malagasy freshwater fish species kept in zoos worldwide, of which 19 are endemic and threatened (22 if counting species kept by private breeders). Nine of the 19 Malagasy freshwater fish species kept in zoos have successfully reproduced within the 12 months preceding our survey. The ex situ conservation activities for threatened Malagasy freshwater fishes thus have not improved significantly since the strong start in the early 2000s. More than half of the 50 threatened endemic Malagasy freshwater fish species (viz. 31 species) are not kept ex situ, including 11 species ranked as Critically Endangered. Based on these findings we call for a better distribution of offspring among institutions, including private breeders in the framework of citizen conservation initiatives; a closer connection of ichthyological field research in Madagascar with conservation breeding efforts to set up ex situ populations—both in Madagascar and abroad—of species not yet kept in captivity; and the development of effective, integrated in situ and ex situ conservation strategies.