First record of the coypu Myocastor coypus (Molina, 1782)for the Arthur Thomas Municipal Park in themunicipality of Londrina, Paraná / Primeiro registro de ratão-do-banhado Myocastor coypus(Molina, 1782) para o Parque Municipal ArthurThomas no município de Londrina, Paraná

Myocastor coypus (coypu or nutria) is considered one of the 100 worst invasive species in the world due to its risk to local wildlife, such as waterfowl, zoonotic risks, and environmental damage, such as riverbank erosion, arising from its habit of constructing burrows along the edge of water bodies. The presence of M. coypus is already known locally in the municipality of Londrina based on records at Igapó Lake. This paper presents the first record of M. coypus in Arthur Thomas Municipal Park, a Conservation Unit of Integral Protection located in the urban area of Londrina. The records were obtained through direct observation of one live individual and one carcass during campaigns to monitor medium and large mammals. Subsequently, ten records were obtained using camera traps, of unknown gender, located near waterbodies. We emphasize the need for continuous fauna monitoring in conservation units to detect and verify potential increases in invasive alien species populations that can result in environmental damage.

A espécie Myocastor coypus (ratão-do-banhado) é considerada uma das 100 piores espécies invasoras do mundo por representar risco para a fauna local, como aves aquáticas, e risco de zoonoses, além de causar danos ambientais, como desbarrancamento de encostas de rios, devido ao seu hábito de construção de tocas nas margens de corpos d'água. A presença de M. coypus já é conhecida localmente no município de Londrina a partir de registros no Lago Igapó. Assim, este estudo apresenta o primeiro registro de M. coypus no Parque Municipal Arthur Thomas, uma Unidade de Conservação de Proteção Integral localizada na zona urbana de Londrina. Os registros foram obtidos através da observação direta de um indivíduo vivo e uma carcaça durante campanhas de monitoramento de mamíferos de médio e grande porte. Posteriormente foram obtidos dez registros por armadilha fotográfica de indivíduos de sexo desconhecido, próximos a corpos d'água. Enfatiza-se a necessidade do monitoramento contínuo da fauna em áreas de conservação para a detecção do potencial aumento na população de espécies exóticas e invasoras que podem causar severos danos ambientais.

The Mediterranean Mussel Mytilus galloprovincialis (Mollusca: Bivalvia) in Chile: Distribution and Genetic Structure of a Recently Introduced Invasive Marine Species.

The genetic characteristics of invasive species have a significant impact on their ability to establish and spread. The blue mussel (Mytilus galloprovincialis), native to the Mediterranean Sea, is a leading invasive species of intertidal coasts throughout much of the world. Here, we used mitochondrial DNA sequence data to investigate the genetic diversity and phylogeographic structure of invasive (M. galloprovincialis) versus native (Mytilus chilensis) populations of blue mussels in Chile. We evaluated whether genetic diversity in invasive populations could be explained by the genetic characteristics of the native sources from which they might be derived. A phylogenetic analysis confirmed two lineages of the invasive M. galloprovincialis, i.e., the NW Atlantic and the Mediterranean lineages. We found no evidence of genetic structure in the invasive range of M. galloprovincialis in Chile, most probably because of its recent arrival. We did, however, detect a spatial mixture of both M. galloprovincialis lineages at sampling locations along the Chilean coast, giving rise to higher levels of genetic diversity in some areas compared to the population of native M. chilensis. The coastal area of the invasion is still small in extent (~100 km on either side of two large ports), which supports the hypothesis of a recent introduction. Further expansion of the distribution range of M. galloprovincialis may be limited to the north by increasing water temperatures and to the south by a natural biogeographic break that may slow or perhaps stop its spread. The use of internal borders as a tool to minimise or prevent M. galloprovincialis spread is therefore a genuine management option in Chile but needs to be implemented rapidly.

Inverse priority effects: A role for historical contingency during species losses.

Communities worldwide are losing multiple species at an unprecedented rate, but how communities reassemble after these losses is often an open question. It is well established that the order and timing of species arrival during community assembly shapes forthcoming community composition and function. Yet, whether the order and timing of species losses can lead to divergent community trajectories remains largely unexplored. Here, we propose a novel framework that sets testable hypotheses on the effects of the order and timing of species losses-inverse priority effects-and suggests its integration into the study of community assembly. We propose that the order and timing of species losses within a community can generate alternative reassembly trajectories, and suggest mechanisms that may underlie these inverse priority effects. To formalize these concepts quantitatively, we used a three-species Lotka-Volterra competition model, enabling to investigate conditions in which the order of species losses can lead to divergent reassembly trajectories. The inverse priority effects framework proposed here promotes the systematic study of the dynamics of species losses from ecological communities, ultimately aimed to better understand community reassembly and guide management decisions in light of rapid global change.

A simulation study evaluating how population survival and genetic diversity in a newly established population can be affected by propagule size, extinction rates, and initial heterozygosity.

The introduction and establishment of invasive species in regions outside their native range, is one of the major threats for the conservation of ecosystems, affecting native organisms and the habitat where they live in, causing substantial biological and monetary losses worldwide. Due to the impact of invasive species, it is important to understand what makes some species more invasive than others. Here, by simulating populations using a forward-in-time approach combining ecological and single polymorphic nucleotides (SNPs) we evaluated the relation between propagule size (number of individuals = 2, 10, 100, and 1,000), extinction rate (with values 2%, 5%, 10%, and 20%), and initial heterozygosity (0.1, 0.3, and 0.5) on the population survival and maintenance of the heterozygosity of a simulated invasive crab species over 30 generations assuming a single introduction. Our results revealed that simulated invasive populations with initial propagule sizes of 2-1,000 individuals experiencing a high extinction rate (10-20% per generation) were able to maintain over 50% of their initial heterozygosity during the first generations and that under scenarios with lower extinction rates invasive populations with initial propagule sizes of 10-1,000 individuals can survive up to 30 generations and maintain 60-100% of their initial heterozygosity. Our results can help other researchers better understand, how species with small propagule sizes and low heterozygosities can become successful invaders.

Effects of substratum type and orientation on the recruitment of bryozoans in an artificial area of the Western Atlantic.

Bryozoans are commonly associated with various artificial structures in marine environments and have been responsible for several bioinvasion events worldwide. Understanding the interactions between bryozoans and artificial structures is therefore essential to prevent the establishment and spread of potential bioinvaders. This study investigated bryozoan recruitment on four different substrates (PET, nautical ropes, metal, and PVC) placed in three orientations (vertical, horizontal facing down and facing up) in an area of the Western Atlantic. In total, 15 species of bryozoans were found. The results revealed significant variations in assemblages' richness, with bryozoans showing a preference for settling on PVC (14 species found) and on the underside of horizontal substrates (15 species found), resulting in the higher representativity observed in this study. Cryptogenic (nine species) and exotic (five species) bryozoans dominated the assemblages in all treatments, indicating that the type of substrate (especially artificial) and its orientation can favor the settlement of bryozoans, particularly non-native species. Therefore, the availability of multiple types of artificial substrates in marine environments should be treated as a cause for concern.

Rocky reef incursions: challenges faced by reef fishes in a Brazilian Hope Spot region.

Biodiversity conservation has been a critical challenge faced by environmental managers worldwide. From 2020 to 2022, a total of 576 underwater visual censuses focused on reef fishes, marine litter (ML), and non-native species were performed in the newest Brazilian Hope Spot, to understand the distribution, characteristics, and effects of ML and Tubastraea spp., on the reef fish community. Plastic was the main category recorded (34.54 %), followed by Metal and Line (mostly fishing gear within a Marine Protected Area). Tubastraea spp. was widely distributed, especially between 10-20 meters deep. The t-test analysis showed that fish abundance and richness were significantly higher at low Tubastraea cover areas. Our efforts present the baseline of ML (mean 1.92 ± 1.5 items/100 m2) and non-native species occurrence (15) and distribution (including three new records) showing their negative impacts on rocky reef ecosystems and provide managers support in the elaboration of marine conservation strategies.

Ecosystem variables importance in the presence and abundance of a globally invasive fish.

Changes in physical habitat that are associated with anthropogenic disturbances facilitate the establishment and expansion of non-native species in receiving environments. Here, we evaluated the relative importance of ecosystem variables for the presence and abundance of the invasive fish Poecilia reticulata in Brazil. We collected fish species and assessed environmental variables through an established physical habitat protocol in 220 stream sites located in southeastern and midwestern Brazil. A total of 14,816 P. reticulata individuals were collected in 43 stream sites, and 258 variables that describe the physical characteristics of streams were assessed, including measures of channel morphology, substrate size and type, habitat complexity and cover, riparian vegetation cover and structure, and human influence. Dimensionality reduction methods were employed to limit redundancy, resulting in a smaller set of the most relevant environmental variables. Subsequently, we used random forest models to assess the relative importance of these variables in determining the presence and abundance of P. reticulata. The presence of this invasive fish was primarily explained by human disturbance variables related to urbanization (total impact, pavement, artificial structure areal cover, riparian canopy cover, electrical conductivity, mean thalweg depth, and sand), whereas channel morphology (mean bank full height) and fish cover variables (natural fish cover, and aquatic macrophyte areal cover) were important predictors of its abundance. Identifying which ecosystem variables are favorable to the establishment of non-native species is an important step in preventing future biological invasions, as well as managing those that already occur.

A critical review of the precautionary approach of the IUCN impact classification for non-native taxa.

The International Union for the Conservation of Nature (IUCN) proposes the use of the Environmental Impact Classification for Alien Taxa to standardize the classification of introduced species (IS) based on their environmental impact. The IUCN invoked the precautionary principle (PP) via 2 rules: the impact assigned to a taxon must be the maximum recorded impact across different impact assessments, and when the main driver of environmental damage is unclear, it must be assumed to be caused by the IS. The validity of PP is conditioned on the degree of emergency that warrants urgent decisions and on the scientific evidence demonstrating the advantages of applying a preventive measure. The application of an impact classification system does not arise in the context of an emergency that requires management; it occurs before the decision-making phase. Thus, PP should not be used in early steps of the risk analysis process. The IUCN also did not provide enough scientific basis to justify the use of PP. Instead, the PP rules appear to be rooted primarily in the ethical value system underlying conservation science. Conservationists assign intrinsic value to native species by virtue of their roles and relationships within ecological and evolutionary systems and processes; thus, individuals introduced in new environments not only cease to have value because they are no longer part of that natural diversity and lack those links with the rest of the ecosystem, but they become a threat to what conservationists value most. The consequence of this belief is that all introduced taxa will have an impact at some level, suggesting that values justify the PP rules.

La Unión Internacional para la Conservación de la Naturaleza (UICN) propone usar la Clasificación del Impacto Ambiental para Taxones Exóticos (CIATE) para estandarizar la clasificación de las especies introducidas con base en su impacto ambiental. La UICN invocó el principio de precaución (PP) mediante dos reglas: el impacto asignado a un taxón debe ser el mayor impacto registrado en diferentes evaluaciones de impacto y cuando no sea claro el principal causante del daño ambiental, se debe asumir que lo causa la especie introducida. La validez del PP está condicionada por el grado de emergencia que amerite decisiones urgentes y por la evidencia científica que demuestre las ventajas de aplicar una medida preventiva. La aplicación de un sistema de clasificación de impactos no surge del contexto de una emergencia que requiere gestión, sino que ocurre antes de la fase de toma de decisiones. Por esto, el PP no debería usarse durante los primeros pasos del proceso de análisis de riesgo. La UICN tampoco proporcionó suficientes fundamentos científicos para justificar el uso del PP. En su lugar, las reglas del PP parecen estar ancladas principalmente en el sistema de valor ético subyacente a las ciencias de la conservación. Los conservacionistas les asignan un valor intrínseco a las especies nativas por su papel y sus relaciones dentro de los sistemas y procesos ecológicos y evolutivos; los individuos introducidos en ambientes nuevos no sólo dejan de tener valor porque ya no forman parte de la diversidad natural y carecen de esas conexiones con el resto del ecosistema, sino también se vuelven una amenaza para lo que más valoran los conservacionistas. Esta creencia tiene como consecuencia que todos los taxones introducidos tendrán un impacto a cierto nivel, lo que sugiere que el valor justifica las reglas del PP.

Antibiotic usage patterns in exotic pets: A study in Curitiba, Paraná, Brazil.

Background: The link between the reckless use of antimicrobials with the increasing development of multidrug-resistant strains of antibiotics is well established. To control the spread of antimicrobial resistance (AMR), action plans, recommendations and guidelines on the prudent use of antibiotics have been developed for food-producing animals and companion animals but appear to be lacking in exotic pets due to the scarcity of data and information on the use of antibiotics in these species. Aim: The purpose of this study is to bring qualitative and quantitative data regarding the use of antimicrobials in exotic pets in a veterinary center in southern Brazil, seeking to measure the consumption of these animals to determine and guide future actions to combat AMR. Methods: A retrospective observational study was conducted by surveying 2,190 open care records in a specialized clinic of wildlife medicine in 2018. Data evaluation was performed in a descriptive, qualitative, and quantitative way, and the analysis of antimicrobial consumption was performed by calculating the daily dose/g of animal ml/day/kg by animal order, condition and active principle, adaptation to DDDVet. For statistical analysis, Levene´s, ANOVA followed by Tukey´s tests were used. Results: Approximately 57% (1250/2190) of the visits made use of one or more antimicrobials in the treatment of animals referred to the clinic. Of these, 67% (n = 839) were birds, 26% (n = 327) were mammals, and 7% (n = 84) were reptiles. In 2018, the total consumption of antimicrobials prescribed was 2.21 l for a total biomass of 129.24 kg. The relation between the dosages of the main antimicrobials used and the conditions treated showed that there is no variation between the treatments by disease and by animal class, due to the great variation within each group. Conclusion: The antimicrobial prescription in exotic pets requires a multifaceted and dynamic approach applied to safeguard the efficacy of the antimicrobials, optimizing consumption, minimizing the emergence of AMR and other possible adverse effects, and considering the physiological differences present within each species. The doses between the different classes and conditions do not obtain a significant difference, reflected in a possible nonstandardization of the dosages used, requiring further investigation of the recommended dosages for each animal species, avoiding the over or underdosing of these drugs. It is worth highlighting that professionals must always make rational use of antimicrobials in these species.

An overview of fish stocking in Brazil

Fish stocking is a common management strategy in Brazil, yet no assessment has examined its real extent and features. The present work investigated fish stocking practices in Brazil between 2010 and 2019 to characterize propagule pressure, species composition, the use of non-native species, geographical and temporal trends, environment types, and responsible agencies. Based on information disseminated on the internet, the study detected 1,155 stocking events (ca. 115 events/year). In total, ca. 56.4 million fish were stocked, with an average of ca. 90 thousand fish/event. We found events in all Brazilian regions involving 436 municipalities and 21 states. Most events occurred in the Northeast region (66.3%), which received alone ca. 41 million fish. Reservoirs were the primary target environment, and the public sector conducted most events. Fish stocking involved 63 taxa, including 14 non-native taxa and three hybrids. Considering the events that informed composition, 62.4% released non-native species, which summed 19.7 million fish. These results provide a broad overview of fish stocking practices in Brazil, and reveal that this action is widely disseminated. Its frequent use, associated with the lack of proper criteria and the illegal stocking of non-native species, raise concerns about technical aspects, outcomes, and potential environmental impacts.

A estocagem de peixes é uma estratégia de manejo comum no Brasil, mas nenhum estudo investigou sua real extensão e características. O presente trabalho investigou práticas de estocagem de peixes realizadas no Brasil entre 2010 e 2019, para caracterizar a pressão de propágulos, composição de espécies, participação de espécies não-nativas, variação espaço-temporal, ambientes e órgãos responsáveis. Com base em informações divulgadas na internet, o estudo detectou 1155 eventos de estocagem (ca. 115 eventos/ano). No total, ca. 56,4 milhões de peixes foram liberados, com média de ca. 90 mil peixes/evento. Encontramos eventos em todas as regiões brasileiras, envolvendo 436 municípios e 21 estados. A região nordeste somou a maioria dos casos (66,3%), e sozinha recebeu cerca de 41 milhões de peixes. Os reservatórios foram o principal ambiente alvo, sendo o setor público o principal responsável pelas ações. A estocagem de peixes envolveu 63 táxons, incluindo 14 táxons não-nativos e três híbridos. Considerando os eventos que informaram a composição das espécies, 62,4% liberaram espécies não-nativas, que somaram 19,7 milhões de peixes. Estes resultados fornecem um amplo panorama das práticas de estocagem de peixes no Brasil, e revelam que essa ação de manejo é amplamente disseminada. Seu uso frequente, associado com a falta de critérios apropriados e a soltura ilegal de espécies não-nativas, suscita preocupações quanto a aspectos técnicos, resultados, e potenciais impactos ambientais.

Diversidad específica y taxonómica de la ictiofauna del Río Amacuzac, Morelos, México / Specific and taxonomic diversity of the ichthyofauna of the Amacuzac River, Morelos, Mexico

Resumen Introducción: La diversidad de una comunidad biológica es el resultado de procesos ecológicos e históricos, los cuales, analizados en conjunto, producen una mejor comprensión de las causas que la generan. Objetivo: Actualizamos y analizamos la diversidad específica y taxonómica de la ictiofauna del río Amacuzac, México. Métodos: Durante cinco temporadas de muestreo (2019-2020), recolectamos peces de diez sitios en el río y aplicamos un análisis de conglomerados a las variables del hábitat. Resultados: Recolectamos 7 638 individuos, siete de especies nativas y nueve no nativas, incluyendo Copadichromis borleyi, un nuevo registro para el Amacuzac. La riqueza por sitio osciló entre ocho y 13 especies. Las variables del hábitat definieron cuatro grupos. Las especies más abundantes fueron: Poeciliopsis gracilis, Poecilia maylandi y Amatitlania nigrofasciata. Las especies menos abundantes fueron: Pterygoplichtys pardalis, Ilyodon whitei, Copadichromis borleyi e Ictalurus punctatus. Las especies más relevantes fueron: A. nigrofasciata, Amphilophus istlanus, Andinoacara rivulatus, Notropis boucardi, Oreochormis sp., P. maylandi, P. gracilis y Thorichthys maculipinis. Las especies más restringidas fueron: Atherinella balsana, C. borleyi e I. punctatus. Conclusiones: Las especies en peligro de extinción, A. istlanus y N. boucardi, aun prevalecen en el río. Además, se muestra un aumento en el número de especies no nativas. Analizar la diversidad desde dos perspectivas, aporta una visión más completa de los cambios que se dan en el Río Amacuzac como consecuencia del establecimiento de especies, información que es importante para futuras estrategias de conservación.

Abstract Introduction: The diversity of a biological community is the result of ecological and historical processes, which, when analyzed jointly, produce a better understanding of the causes that generate it. Objective: We update and analyze the specific and taxonomic diversity of the ichthyofauna of the Amacuzac River, Mexico. Methods: During five sampling seasons (2019-2020) we collected fishes from ten sites in the river and applied a cluster analysis to habitat variables. Results: We collected 7 638 individuals; seven were native species and nine were non-native, including Copadichromis borleyi, a new record for the Amacuzac. Richness per site ranged from eight to 13 species. Habitat variables defined four groups. The most abundant species were Poeciliopsis gracilis, Poecilia maylandi and Amatitlania nigrofasciata. The least abundant species were: Pterygoplichtys pardalis, Ilyodon whitei, Copadichromis borleyi and Ictalurus punctatus. The most prevalent species were: A. nigrofasciata, Amphilophus istlanus, Andinoacara rivulatus, Notropis boucardi, Oreochormis sp., P. maylandi, P., gracilis and Thorichthys maculipinis. The most restricted species were: Atherinella balsana, C. borleyi and I. punctatus. Conclusions: Endangered species such as A. istlanus and N. boucardi are still prevalent in the river, but non-native species continue to increase. Analyzing the diversity from two perspectives provides a more complete view of the changes taking place in the Amacuzac River as a consequence of species establishment, information that is important for future conservation strategies.

Do People Care about the Origin of Wildlife? The Role of Social Stereotypes on Public Preference for Exotic Animals.

People's attitudes to animals are becoming increasingly important for the success of invasive species management. We asked college students from Argentina to fill a questionnaire that included a question about their favorite free-living animal. A total of 159 responses were obtained. Native species were significantly less preferred than non-native species. We tested if these preferences were associated with animal stereotypes. The stereotype hypothesis predicts that animals from the contemptible stereotype (invertebrate, rodents, and reptiles) should be the least preferred taxa, and animals from the protective stereotype (pets, horses, and primates) should be the most preferred taxa; animals from the subordination (lagomorphs and birds) and threatening-awe stereotype (large carnivores) should show intermediate preferences. The first prediction was supported. However, students showed significant preference for non-native taxa included in the threatening-awe stereotype. We proposed that people prefer large carnivores (stereotypically strong, intelligent, and beautiful animals) when they are exotic, because they did not represent a risk.

The alien octocoral Carijoa riisei is a biogenic substrate multiplier in artificial Brazilian shipwrecks.

Despite the obvious negative effects caused by invasive species, some recent studies have shown that the impacts at local scale are diverse and not necessarily negative. Arborescent benthic organisms such as octocorals form three-dimensional structures capable of increasing the amount of substrate available and providing shelter for epibiont species. We investigated the role of the alien octocoral Carijoa riisei on the diversity of benthic communities in three shipwrecks on the north-eastern coast of Brazil. We expected that (a) the fauna associated with the octocoral are richer and more diverse compared to the adjacent; (b) some species are exclusively associated with C. riisei; (c) the species that are present both in the areas with and without C. riisei have a greater abundance when associated with the octocoral. For this, we compared the macrobenthic communities associated with C. riisei to those found in adjacent areas where the octocoral was absent. Our study showed that the communities associated with the octocoral were 1.5 times richer and 10 times more abundant than adjacent communities, with 29 exclusive taxa. The dominant taxa were the amphipods Ericthonius brasiliensis and Podocerus brasiliensis and polychaetes of the family Syllidae. These taxa were present in areas with presence and absence of C. riisei, but their abundance was significantly greater where the octocoral was present. Our results reinforce the idea that Carijoa riisei acts as an ecosystem engineer in coastal reefs, creating new habitats and increasing diversity at a local scale, even though it is an alien species.

The disruption of a keystone interaction erodes pollination and seed dispersal networks.

Understanding the impacts of global change on ecological communities is a major challenge in modern ecology. The gain or loss of particular species and the disruption of key interactions are both consequences and drivers of global change that can lead to the disassembly of ecological networks. We examined whether the disruption of a hummingbird-mistletoe-marsupial mutualism by the invasion of non-native species can have cascading effects on both pollination and seed dispersal networks in the temperate forest of Patagonia, Argentina. We focused on network motifs, subnetworks composed of a small number of species exhibiting particular patterns of interaction, to examine the structure and diversity of mutualistic networks. We found that the hummingbird-mistletoe-marsupial mutualism plays a critical role in the community by increasing the complexity of pollination and seed dispersal networks through supporting a high diversity of interactions. Moreover, we found that the disruption of this tripartite mutualism by non-native ungulates resulted in diverse indirect effects that led to less complex pollination and seed dispersal networks. Our results demonstrate that the gains and losses of particular species and the alteration of key interactions can lead to cascading effects in the community through the disassembly of mutualistic networks.

Counterurbanization: A neglected pathway of forest transition.

Human settlement into rural areas (counterurbanization) is generating new patterns of reforestation, with distinctive features compared to the previously considered pathways of forest transition through "economic development" and "forest scarcity". Here, we discuss the specific features of this neglected pathway of forest recovery and describe the process with the support of study cases around the world. This pathway includes specific motivations (e.g., natural amenities, outdoor recreation), particular socio-economic processes, conflicts between newcomers and locals, and specific ecological outcomes (e.g., a larger proportion of non-native species in the new forests). Although this pathway locally affects small areas, as a widespread and expanding process around the world, counterurbanization could have a growing global effect, with the potential to modify biodiversity, ecosystem services, and cultural values. These novel characteristics should be further explored to better understand the patterns and processes of forest transitions in a context of a globally connected world.

A keystone mutualism promotes resistance to invasion.

It is not uncommon for one or a few species, and their interactions, to have disproportionate effects on other species in ecological communities. Such keystone interactions might affect how communities respond to the invasion of non-native species by preventing or inhibiting the establishment, spread or impact of non-native species. We explore whether a keystone mutualism among a hummingbird-mistletoe-marsupial promotes ecological resistance to an invasive pollinator, the bumblebee Bombus terrestris, by comparing data collected at sites prior to bumblebee invasion to data collected 11 years after the invasion in sites with and without the keystone mutualism. We built pollination networks and focused on network motifs, regarded as building blocks of networks, to identify the central pollinators and estimate the change in their interactions after invasion of B. terrestris. We also estimated the interaction rewiring across the season in post-invasion networks and tested it as a possible mechanism explaining how the keystone mutualism increased ecological resistance to invasion. We found two times more species in post-invasion sites with the keystone mutualism than in post-invasion sites without the keystone mutualism. Moreover, we found that invasive bumblebee reduced the strength and interaction niche of the five central pollinator species while increasing its own strength and interaction niche, suggesting a replacement of interactions. Also, we found that the keystone mutualism promoted resistance to B. terrestris invasion by reducing its negative impacts on central species. In the presence of the keystone mutualism, central species had three times more direct interactions than in sites without this keystone mutualism. The higher interaction rewiring, after invasion of B. terrestris, in sites with the keystone mutualism indicates greater chances of central pollinators to form new interactions and reduces their competence for resources with the non-native bumblebee. Our results demonstrate that a keystone mutualism can enhance community resistance against the impacts of a non-native invasive pollinator by increasing species diversity and promoting interaction rewiring in the community. This study suggests that the conservation of mutualisms, especially those considered keystone, could be essential for long-term preservation of natural communities under current and future impacts of global change.

Es común que una o unas pocas especies y sus interacciones tengan efectos desproporcionado sobre otras especies en las comunidades. Estas especies y sus interacciones claves podrían afectar el modo en que las comunidades responden a la invasión de especies no nativas al prevenir o disminuir su establecimiento, su propagación o el impacto de las mismas. En este estudio evaluamos si un mutualismo clave entre un colibrí, un muérdago y un marsupial promueve la resistencia de la comunidad frente a un polinizador invasor, el abejorro Bombus terrestris, mediante la comparación de datos colectados en sitios previos a la invasión del abejorro y datos colectados 11 años después de su invasión, en sitios con y sin el mutualismo clave. Construimos redes ecológicas planta-polinizador y nos centramos en los modos de interacción ("interaction motifs"), los cuales son usados como bloques en la construcción de las redes, para identificar los polinizadores centrales y estimar el cambio en sus interacciones después de la invasión de B. terrestris. Además, en las redes posteriores a la invasión estimamos la reconexión de interacciones a lo largo de la temporada y la evaluamos como un posible mecanismo mediante la cual el mutualismo clave aumentó la resistencia a la invasión. En sitios posteriores a la invasión con el mutualismo clave encontramos dos veces más especies que en sitios posteriores a la invasión ausentes de éste. Además, en los sitios ausentes del mutualismo clave, encontramos que el abejorro invasor redujo la fuerza y el nicho de interacción de los cinco polinizadores centrales mientras incrementó su propia fuerza y nicho de interacciones, sugiriendo un reemplazo de interacciones. Asimismo, encontramos que el mutualismo clave promovió la resistencia de la comunidad a la invasión de B. terrestris al reducir sus impactos negativos sobre las especies centrales. En presencia del mutualismo clave, las especies centrales presentaron tres veces más interacciones directas que en sitios ausentes de esta interacción. La gran reconexión de interacciones encontrada en sitios posteriores a la invasión con el mutualismo clave indica mayores probabilidades de que los polinizadores centrales formen nuevas interacciones y reduzcan la competencia por recursos con el abejorro no nativo. Nuestros resultados demuestran que un mutualismo clave puede mejorar la resistencia de la comunidad frente a los impactos de especies invasoras al incrementar la diversidad de especies y promover la reconexión de interacciones en la comunidad. Este estudio sugiere que la conservación de las interacciones mutualistas, principalmente aquellas consideradas claves, podría ser esencial para preservar las comunidades naturales frente a los impactos del cambio global.

Do cage fish farms interfere with the food aspects of the wild species Metynnis lippincottianus (Characiformes, Serrasalmidae)? / Pisciculturas em tanques-rede interferem sobre os aspectos alimentares da espécie silvestre Metynnis lippincottianus (Characiformes, Serrasalmidae)?

We evaluated the differences in the diet and trophic guild of Metynnis lippincottianus under the in-fluence of cage fish farms in the Neotropical reservoir. We collected samples from two areas (cage farm and control) in March and June 2019. Stomach contents were examined, and food items were identified and quantified using the volumetric method. Differences in diet composition were evaluated using PERMANOVA and SIMPER analyses, while trophic niche breadth was determined using PERMDISP. The trophic guild for each area was also determined. Significant differences in diet between cage farm and control areas were observed, due to consumption of pelleted feed, mi-crocrustaceans, Egeria sp., and filamentous algae. In both sampling areas, M. lippincottianus was classified as algivorous. Despite the pelleted feed consumption in the cage farm area, no differen-ces were observed in trophic niche breadth and the trophic guild. In addition, algae and macro-phytes still accounted for the majority of this species' diet in both areas, indicating partitioning of resources. This resource partitioning may favor coexistence, but it is worth mentioning that pelleted feed consumption still indicates the influence of cage fish farms on the diet of wild fish.(AU)

Avaliamos as diferenças na dieta e guilda trófica de Metynnis lippincottianus sob a influência de pis-ciculturas em um reservatório neotropical. Coletamos amostras de duas áreas (tanques-rede e con-trole) em março e junho de 2019. O conteúdo estomacal foi examinado e os itens alimentares foram identificados e quantificados usando o método volumétrico. As diferenças na composição da dieta foram avaliadas usando as análises PERMANOVA e SIMPER, enquanto a amplitude do nicho trófico foi determinada usando PERMDISP. A guilda trófica para cada área também foi determinada. Foram observadas diferenças significativas na dieta entre as áreas tanques e controle, devido ao consumo de ração, microcrustáceos, Egeria sp. e algas filamentosas. Em ambas as áreas de amostragem, M. lippincottianus foi classificado como algívoro. Apesar do consumo de ração na área tanque, não foram observadas diferenças na amplitude do nicho trófico e na guilda trófica. Além disso, algas e macrófitas ainda representam a maior parte da dieta desta espécie em ambas as áreas, indicando partilha de recursos. Essa partilha de recursos pode favorecer a coexistência, mas vale ressaltar que o consumo de ração ainda indica influências das pisciculturas em tanques-rede sob a dieta dos peixes silvestres.(AU)

Is the southern crab Halicarcinus planatus (Fabricius, 1775) the next invader of Antarctica?

The potential for biological colonization of Antarctic shores is an increasingly important topic in the context of anthropogenic warming. Successful Antarctic invasions to date have been recorded exclusively from terrestrial habitats. While non-native marine species such as crabs, mussels and tunicates have already been reported from Antarctic coasts, none have as yet established there. Among the potential marine invaders of Antarctic shallow waters is Halicarcinus planatus (Fabricius, 1775), a crab with a circum-Subantarctic distribution and substantial larval dispersal capacity. An ovigerous female of this species was found in shallow waters of Deception Island, South Shetland Islands in 2010. A combination of physiological experiments and ecological modelling was used to assess the potential niche of H. planatus and estimate its future southward boundaries under climate change scenarios. We show that H. planatus has a minimum thermal limit of 1°C, and that its current distribution (assessed by sampling and niche modelling) is physiologically restricted to the Subantarctic region. While this species is presently unable to survive in Antarctica, future warming under both 'strong mitigation' and 'no mitigation' greenhouse gas emission scenarios will favour its niche expansion to the Western Antarctic Peninsula (WAP) by 2100. Future human activity also has potential to increase the probability of anthropogenic translocation of this species into Antarctic ecosystems.

The role of artificial habitats on fouling bryozoan fauna in the southwestern Atlantic.

Artificial habitats, such as harbours and marinas, are entry doors for the introduction and dispersal of species. Surveys on fouling community in these habitats help to understand preventing environmental impacts and management of invasive species. Thus, a survey on fouling bryozoan fauna was carried out along 17 artificial habitats (eight harbours and nine marinas) from three coastal stretches in Southwestern Atlantic. A total of 55 species were identified, including 13 non-native, 33 cryptogenic and nine native taxa. Only five bryozoan species were found in more than 75% of sampled sites. Our analysis revealed that bryozoan fouling communities in artificial habitats do not vary significantly between commercial and recreational localities. However, we also found that faunal assemblages varied significantly along Brazilian coastal stretches that are distinguished by environmental conditions, such as salinity and temperature.

A new species of Satanoperca (Teleostei: Cichlidae) from the Rio Tocantins basin, Brazil

A new species of Satanoperca is described from the Rio Araguaia, Rio Tocantins basin, Brazil, and non-native records are available in the upper Rio Paraná basin. It differs from congeneric species by color pattern characters, such as head and flank marks. It is included in the Satanoperca jurupari species group, characterized by the absence of black rounded blotches on the flank, and low meristic values. A description of the ontogeny of melanophore marks of the S. jurupari species group revealed two different types of arrangement on the flank and numerous melanophore marks on the head. A discussion on morphologically diverse assemblages in the S. jurupari species group is also provided.(AU)

Uma nova espécie de Satanoperca é descrita do rio Araguaia, bacia do rio Tocantins, Brasil, e registros não-nativos estão disponíveis para a bacia do alto rio Paraná. Pode ser diagnosticada de suas congêneres por caracteres do padrão de colorido como marcas na cabeça e flanco. É incluída no grupo Satanoperca jurupari pela ausência de máculas pretas arredondadas no flanco e menores valores de contagens. Uma descrição da ontogenia das marcas melanofóricas do grupo S. jurupari revelou dois tipos diferentes de arranjos no flanco e várias marcas melanofóricas na cabeça. Uma discussão sobre assembleias morfologicamente diversas no grupo S. jurupari também é fornecida.(AU)