Long-term studies on West Antarctic Peninsula phytoplankton blooms suggest range shifts between temperate and polar species.

The Western Antarctic Peninsula (WAP) experiences one of the highest rates of sea surface warming globally, leading to potential changes in biological communities. Long-term phytoplankton monitoring in Potter Cove (PC, King George Island, South Shetlands) from the 1990s to 2009 revealed consistently low biomass values, and sporadic blooms dominated by cold-water microplankton diatoms. However, a significant change occurred between 2010 and 2020, marked by a notable increase in intense phytoplankton blooms in the region. During this period, the presence of a nanoplankton diatom, Shionodiscus gaarderae, was documented for the first time. In some instances, this species even dominated the blooms. S. gaarderae is recognized for producing blooms in temperate waters in both hemispheres. However, its blooming in the northern Southern Ocean may suggest either a recent introduction or a range shift associated with rising temperatures in the WAP, a phenomenon previously observed in experimental studies. The presence of S. gaarderae could be viewed as a warning sign of significant changes already underway in the northern WAP plankton communities. This includes the potential replacement of microplankton diatoms by smaller nanoplankton species. This study, based on observations along the past decade, and compared to the previous 20 years, could have far-reaching implications for the structure of the Antarctic food web.

Detection of Apicystis bombi (Apicomplexa: Neogregarinorida) in carpenter bees of Argentina.

Historically, the neogregarine Apicystis bombi was isolated almost exclusively from bumble bees (Bombus spp.) where it disrupts adipose tissue, increasing hosts' mortality rates. Records in solitary bees are scarce worldwide. To check for its presence in carpenter bees (genus Xylocopa), campaigns were performed in Argentina capturing 154 individuals of five species (X. augusti, X. splendidula, X. atamisquensis, X. frontalis, X. nigrocincta). The presence of A. bombi was detected by molecular means in X. augusti, X. atamisquensis, and X. nigrocincta in four of the nine provinces screened. The pathogenesis and eventual impact that A. bombi may cause in individuals or populations of Xylocopa species remain unknown. The presence of A. bombi in northern Argentina would be contradictory to the hypothesis that its occurrence is the exclusive result of its introduction to South America through invasive, infected exotic bumble bees.

Aliens Coming by Ships: Distribution and Origins of the Ocellated Skink Populations in Peninsular Italy.

The ocellated skink (Chalcides ocellatus) is a widespread lizard, naturally distributed between the Maghreb and coastal Pakistan, with few insular populations in the Mediterranean coastal area. Some populations of this species have also been recorded in peninsular Italy, Campania and Southern Tuscany due to accidental introductions via touristic and commercial routes. In this work, we conducted genetic analyses on mitochondrial DNA COXI, cytb and 16S mtDNA genes on a sample of Italian insular and peninsular populations. Differently from what previously suggested, the nucleus in Portici (Southern Italy) may have originated from Sardinia. The intense trade and touristic traffic between Sardinia and Southern Tuscany may have been responsible for the introduction of this lizard also to Central Italy.

Evaluating unintended consequences of intentional species introductions and eradications for improved conservation management.

Increasingly intensive strategies to maintain biodiversity and ecosystem function are being deployed in response to global anthropogenic threats, including intentionally introducing and eradicating species via assisted migration, rewilding, biological control, invasive species eradications, and gene drives. These actions are highly contentious because of their potential for unintended consequences. We conducted a global literature review of these conservation actions to quantify how often unintended outcomes occur and to elucidate their underlying causes. To evaluate conservation outcomes, we developed a community assessment framework for systematically mapping the range of possible interaction types for 111 case studies. Applying this tool, we quantified the number of interaction types considered in each study and documented the nature and strength of intended and unintended outcomes. Intended outcomes were reported in 51% of cases, a combination of intended outcomes and unintended outcomes in 26%, and strictly unintended outcomes in 10%. Hence, unintended outcomes were reported in 36% of all cases evaluated. In evaluating overall conservations outcomes (weighing intended vs. unintended effects), some unintended effects were fairly innocuous relative to the conservation objective, whereas others resulted in serious unintended consequences in recipient communities. Studies that assessed a greater number of community interactions with the target species reported unintended outcomes more often, suggesting that unintended consequences may be underreported due to insufficient vetting. Most reported unintended outcomes arose from direct effects (68%) or simple density-mediated or indirect effects (25%) linked to the target species. Only a few documented cases arose from more complex interaction pathways (7%). Therefore, most unintended outcomes involved simple interactions that could be predicted and mitigated through more formal vetting. Our community assessment framework provides a tool for screening future conservation actions by mapping the recipient community interaction web to identify and mitigate unintended outcomes from intentional species introductions and eradications for conservation.

Evaluación de las Consecuencias Involuntarias de las Introducciones y Erradicaciones Intencionales de Especies para el Manejo Mejorado de la Conservación Resumen Actualmente se despliegan estrategias cada vez más intensas para mantener la biodiversidad y la función del ecosistema como respuesta a las amenazas antropogénicas mundiales, incluyendo la introducción y erradicación intencionales de especies por medio de la migración asistida, el retorno a la vida silvestre, el control biológico, la erradicación de especies invasoras y la genética dirigida. Estas acciones son muy polémicas por el potencial que tienen para generar consecuencias involuntarias. Realizamos una revisión de la literatura mundial sobre estas acciones de conservación para cuantificar cuán seguido ocurren las consecuencias involuntarias y cuáles son sus causas subyacentes. Para evaluar los resultados de conservación, desarrollamos un marco de trabajo de evaluación comunitaria para mapear sistemáticamente el rango de posibles interacciones para 111 estudios de caso. Con la aplicación de esta herramienta cuantificamos el número de tipos de interacción consideradas en cada estudio y documentamos la naturaleza y la fuerza de los resultados involuntarios. Se reportaron los resultados voluntarios en 51% de los casos, una combinación de resultados voluntarios e involuntarios en 26% de los casos y estrictamente los resultados involuntarios en el 10% de los casos. Por lo tanto, los resultados involuntarios fueron reportados en el 36% de todos los casos evaluados. En la evaluación general de los resultados de conservación (sopesando los efectos voluntarios y. los involuntarios), algunos efectos involuntarios fueron bastante inocuos en relación con el objetivo de conservación, mientras que otros resultaron en consecuencias involuntarias severas para las comunidades receptoras. Los estudios que evaluaron un mayor número de interacciones comunitarias con la especie objetivo reportaron resultados involuntarios con mayor frecuencia, lo que sugiere que las consecuencias involuntarias pueden estar subvaloradas debido al escrutinio insuficiente. La mayoría de los resultados involuntarios reportados surgieron de los efectos directos (68%) o de los efectos indirectos o mediados por la densidad (25%) vinculados con la especie diana. Solamente unos cuantos casos documentados surgieron de interacciones más complejas (7%). Por lo tanto, la mayoría de los resultados involuntarios involucran interacciones simples que podrían ser pronosticadas y mitigadas por medio de un escrutinio más formal. Nuestro marco de trabajo de evaluación comunitaria proporciona una herramienta para la revisión de las acciones de conservación en el futuro mediante el mapeo de la red de interacciones entre comunidades receptoras y para la mitigación de los resultados involuntarios surgidos de las introducciones y erradicaciones intencionales de especies a favor de la conservación.

An intercontinental comparison of insect seed predation between introduced and native oaks.

Novel interactions between introduced oaks and their natural enemies across different continents provide an opportunity to test the enemy release hypothesis (ERH) at local and global scales. Based on the ERH, we assessed the impacts of native seed-feeding insects on introduced and native oaks within and among continents. We combined a common-garden experiment in China and biogeographic literature surveys to measure seed predation by insects and the proportion of acorn embryos surviving after insect infestation among 4 oak species with different geographical origins: Quercus mongolica origin from China, Q. robur and Q. petraea from Europe, and Q. rubra from North America. Mostly supporting the ERH, oaks in introduced continents escaped seed predation compared to those in native continents and compared to other native oaks in introduced continents. Common-garden comparisons showed that total acorn infestation rate of introduced Q. rubra (section Lobatae) was considerably lower than that of native oaks (section Quercus) in China and Europe, likely because of the differences in seed traits associated with different oak sections. Literature surveys showed that seed predation of introduced oaks was lower in the introduced continent than in the native continent. Embryo survival was higher in introduced Q. rubra than native oaks in China and Poland. However, insect seed predation of recently introduced Q. rubra in China was similar to that in Europe, which is not consistent with the ERH. Our results suggest that reduced acorn attack by native insects and higher embryo survival after acorn damage could increase the establishment success or invasion risk of introduced oaks in non-native continents.

Revealing the Introduction History and Phylogenetic Relationships of Passiflora foetida sensu lato in Australia.

Genomic analysis can be a valuable tool to assistmanagement of non-native invasive species, through determining source and number of introductions as well as clarifying phylogenetic relationships. Here, we used whole chloroplast sequencing to investigate the introduction history of Passiflora foetida sensu lato in Australia and clarify its relationship with other Passiflora species present. Phylogenetic analysis of chloroplast genome data identified three separate genetic lineages of P. foetida s. l. present in Australia, indicating multiple introductions. These lineages had affinities to samples from three separate areas within the native range in Central and South America that represented phylogenetically distinct lineages. These results provide a basis for a targeted search of the native range of P. foetida s. l. for candidate biological control agents that have co-evolved with this species and are thus better adapted to the lineages that are present in Australia. Results also indicated that the Passiflora species native to Australia are in a separate clade to that of P. foetida s. l. and other introduced Passiflora species cultivated in Australia. This knowledge is important to assess the likelihood of finding biological control agents for P. foetida s. l. that will be sufficiently host-specific for introduction in Australia. As P. foetida s. l. is a widespread non-native invasive species across many regions of the world, outcomes from this work highlight the importance of first evaluating the specific entities present in a country before the initiation of a biological control program.

Assessment of interspecific interactions between the invasive red-claw crayfish (Cherax quadricarinatus) and the Mozambique tilapia (Oreochromis mossambicus) / Avaliação das interações interespecíficas entre o lagostim invasivo de garra vermelha (Cherax quadricarinatus) e a tilapia de Moçambique (Oreochromis mossambicus)

Abstract The Australian red-claw crayfish, Cherax quadricarinatus, has been introduced for aquaculture purposes worldwide and consequently colonized natural environments, where it might cause ecosystem services losses or adversely affect native species and the local environment. This species was first found in Pequenos Libombos Reservoir in Maputo Province, Southern Mozambique in the late 2009 and is linked to reduction in tilapia fisheries. This study, conducted in 2015 under controlled conditions, aimed to assess the interspecific relationships between the Mozambique tilapia (Oreochromis mossambicus) and the alien crayfish. For both species, no significant differences in growth and survival rates were found between animals reared in the presence versus the absence of heterospecifics, indicating no direct deleterious interspecific effects. Behavioural observations revealed that fish and crayfish competed for shelter and food. Both species reduced the foraging in the presence of heterospecifics during feeding period, in the daytime. Crayfish seemed to have an advantage in competition for shelter, suggesting that they may interfere with tilapia sheltering activity and make tilapia vulnerable to predators in natural habitats.

Resumo O lagostim australiano, Cherax quadricarinatus, tem sido introduzido para fins de aquicultura em todo o mundo e, consequentemente, colonizado ambientes naturais, onde pode coexistir com a biota local sem causar perdas nos serviços dos ecossistemas ou afetar negativamente as espécies nativas e o meio ambiente local. Esta espécie foi encontrada pela primeira vez na Albufeira dos Pequenos Libombos, na Província de Maputo, sul de Moçambique, no final de 2009 e foi relacionada à redução da pesca de tilápias registrada na mesma localidade. Este estudo, conduzido em 2015 sob condições controladas, teve como objetivo avaliar as relações interespecíficas entre a tilápia de Moçambique (Oreochromis mossambicus) e o lagostim invasor (C. quadricarinatus). Para ambas espécies, não foram encontradas diferenças significativas nas taxas de crescimento e sobrevivência entre animais criados na presença versus ausência de heteroespecíficos, indicando ausência de efeitos deletérios interespecíficos diretos. Observações comportamentais revelaram que peixes e lagostins competiam por abrigo e comida. Ambas espécies reduziram o forrageamento na presença de heteroespecíficos durante o período de alimentação, no período diurno. O lagostim parece ter uma vantagem na competição por abrigos, sugerindo que, em habitats naturais eles podem provocar o deslocamento de tilápias de seus abrigos, e deste modo tornar as tilápias vulneráveis aos predadores.

Heat stress tolerance determines the survival and growth of introduced Canadian sugar maple in subtropical China.

The introduction of species contributes to both ecological restoration and regional economics, while serving as a potential strategy to conserve species under rapid climate change. Despite an anticipated significant increase in temperature at high latitudes by the end of the 21st century, very few experimental migration trials have been conducted regarding large climate range changes. We employed a provenance trial by introducing a temperate sugar maple (Acer saccharum Marsh) of three provenances with a mean annual temperature of 3.0 °C in Manitoba, 4.2 °C in Quebec and 9.4 °C in Ontario, Canada, to 15.8 °C at an introduced site in subtropical China. We measured survival, growth, summer photosynthesis in the field and stress-resistance responses under a temperature gradient in growth chambers with first-year seedlings. We found that the Ontario provenance had the highest propensity for survival and growth, followed by the Quebec provenance, while the Manitoba provenance had the lowest. The photosynthetic parameters of the seedlings changed over time of the day, with the Ontario provenance having a higher photosynthesis rate and stomatal conductance than the Quebec and Manitoba provenances. Furthermore, the growth chamber results revealed that the Ontario provenance had the best physiological adjustment for self-protection from heat stress, followed by the Quebec and Manitoba provenances. Our results suggested that the change in climate range drove the survival and growth of introduced seedlings and that the tolerance to summer heat stress through physiological mechanisms was responsible for the success of species introduction, from a cold to a warm climate.

Public perception of river fish biodiversity in four European countries.

Public support for biodiversity conservation is shaped by people's values and their knowledge, beliefs, and attitudes toward the environment. We conducted the first multinational representative survey of the general public's perceptions of river fish biodiversity in France, Germany, Norway, and Sweden. For the online survey, 1000 respondents per country were randomly selected from large panels following country-specific quotas set on age, gender, and educational level. Questions covered people's level of knowledge, beliefs, values, and attitudes toward river fish, environmental threats, and conservation measures. We found that the public had limited knowledge of freshwater fishes. Two non-native species, rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis), were widely perceived as native, whereas native Atlantic salmon (Salmo salar) was mostly classified as native in Scandinavia and largely as non-native in central Europe. These results suggest an extinction of experience paralleling the extirpation or decline of salmon stocks in countries such as Germany and France. Respondents thought pollution was the dominant threat to riverine fish biodiversity. In reality, habitat loss, dams, and the spread of non-native fishes are equally important. Despite limited biological knowledge, respondents from all countries held an overwhelmingly proecological worldview, supported conservation stocking, and appreciated native fishes, although only a minority interacted with them directly. Differences among the 4 countries related to several conservation issues. For example, threats to biodiversity stemming from aquaculture were perceived as more prevalent in Norway compared with the other 3 countries. Promoting fish conservation based on charismatic species and use values of fishes may work well in countries with a strong economic and cultural link to the freshwater environment, such as Norway. In countries where people rather abstractly care for nature, focusing conservation messaging on broader ecosystem traits and non-use values of fishes is likely to win more support.

Predicting the establishment success of introduced target species in grassland restoration by functional traits.

Species-rich semi-natural grasslands are highly endangered habitats in Central Europe and numerous restoration efforts have been made to compensate for the losses in the last decades. However, some plant species could become more easily established than others. The establishment success of 37 species was analyzed over 6 years at two study sites of a restoration project in Germany where hay transfer and sowing of threshing material in combination with additional sowing were applied. The effects of the restoration method applied, time since the restoration took place, traits related to germination, dispersal, and reproduction, and combinations of these traits on the establishment were analyzed. While the specific restoration method of how seeds were transferred played a subordinate role, the establishment success depended in particular on traits such as flower season or the lifeform. Species flowering in autumn, such as Pastinaca sativa and Serratula tinctoria, became established better than species flowering in other seasons, probably because they could complete their life cycle, resulting in increasingly stronger seed pressure with time. Geophytes, like Allium angulosum and Galium boreale, became established very poorly, but showed an increase with study duration. For various traits, we found significant trait by method and trait by year interactions, indicating that different traits promoted establishment under different conditions. Using a multi-model approach, we tested whether traits acted in combination. For the first years and the last year, we found that models with three traits explained establishment success better than models with a single trait or two traits. While traits had only an additive effect on the establishment success in the first years, trait interactions became important thereafter. The most important trait was the season of flowering, which occurred in all best models from the third year onwards. Overall, our approach revealed the potential of functional trait analysis to predict success in restoration projects.

Assessment of interspecific interactions between the invasive red-claw crayfish (Cherax quadricarinatus) and the Mozambique tilapia (Oreochromis mossambicus)

Abstract The Australian red-claw crayfish, Cherax quadricarinatus, has been introduced for aquaculture purposes worldwide and consequently colonized natural environments, where it might cause ecosystem services losses or adversely affect native species and the local environment. This species was first found in Pequenos Libombos Reservoir in Maputo Province, Southern Mozambique in the late 2009 and is linked to reduction in tilapia fisheries. This study, conducted in 2015 under controlled conditions, aimed to assess the interspecific relationships between the Mozambique tilapia (Oreochromis mossambicus) and the alien crayfish. For both species, no significant differences in growth and survival rates were found between animals reared in the presence versus the absence of heterospecifics, indicating no direct deleterious interspecific effects. Behavioural observations revealed that fish and crayfish competed for shelter and food. Both species reduced the foraging in the presence of heterospecifics during feeding period, in the daytime. Crayfish seemed to have an advantage in competition for shelter, suggesting that they may interfere with tilapia sheltering activity and make tilapia vulnerable to predators in natural habitats.

Resumo O lagostim australiano, Cherax quadricarinatus, tem sido introduzido para fins de aquicultura em todo o mundo e, consequentemente, colonizado ambientes naturais, onde pode coexistir com a biota local sem causar perdas nos serviços dos ecossistemas ou afetar negativamente as espécies nativas e o meio ambiente local. Esta espécie foi encontrada pela primeira vez na Albufeira dos Pequenos Libombos, na Província de Maputo, sul de Moçambique, no final de 2009 e foi relacionada à redução da pesca de tilápias registrada na mesma localidade. Este estudo, conduzido em 2015 sob condições controladas, teve como objetivo avaliar as relações interespecíficas entre a tilápia de Moçambique (Oreochromis mossambicus) e o lagostim invasor (C. quadricarinatus). Para ambas espécies, não foram encontradas diferenças significativas nas taxas de crescimento e sobrevivência entre animais criados na presença versus ausência de heteroespecíficos, indicando ausência de efeitos deletérios interespecíficos diretos. Observações comportamentais revelaram que peixes e lagostins competiam por abrigo e comida. Ambas espécies reduziram o forrageamento na presença de heteroespecíficos durante o período de alimentação, no período diurno. O lagostim parece ter uma vantagem na competição por abrigos, sugerindo que, em habitats naturais eles podem provocar o deslocamento de tilápias de seus abrigos, e deste modo tornar as tilápias vulneráveis aos predadores.

From richer to poorer: successful invasion by freshwater fishes depends on species richness of donor and recipient basins.

Evidence for the theory of biotic resistance is equivocal, with experiments often finding a negative relationship between invasion success and native species richness, and large-scale comparative studies finding a positive relationship. Biotic resistance derives from local species interactions, yet global and regional studies often analyze data at coarse spatial grains. In addition, differences in competitive environments across regions may confound tests of biotic resistance based solely on native species richness of the invaded community. Using global and regional data sets for fishes in river and stream reaches, we ask two questions: (1) does a negative relationship exist between native and non-native species richness and (2) do non-native species originate from higher diversity systems. A negative relationship between native and non-native species richness in local assemblages was found at the global scale, while regional patterns revealed the opposite trend. At both spatial scales, however, nearly all non-native species originated from river basins with higher native species richness than the basin of the invaded community. Together, these findings imply that coevolved ecological interactions in species-rich systems inhibit establishment of generalist non-native species from less diverse communities. Consideration of both the ecological and evolutionary aspects of community assembly is critical to understanding invasion patterns. Distinct evolutionary histories in different regions strongly influence invasion of intact communities that are relatively unimpacted by human actions, and may explain the conflicting relationship between native and non-native species richness found at different spatial scales.

Diet shift of Red Belly Pacu Piaractus brachypomus (Cuvier, 1818) (Characiformes: Serrasalmidae), a Neotropical fish, in the Sepik-Ramu River Basin, Papua New Guinea

Introduction of fish species is a globally widespread practice that causes losses of native species and homogenization of diversity within and across continents. Diet assessments are important tools to depict the ecological function of species introduced into novel ecosystem and possible direct and indirect ecological effects. In this study, we compare the diet of Piaractus brachypomus, a mainly frugivorous Neotropical fish, introduced into the Sepik-Ramu River Basin (Papua New Guinea) nearly two decades ago, to that of similar size individuals from Neotropical populations in the Amazon and Orinoco River basins (South America). In contrast to native populations that feed mainly on terrestrial plants and invertebrates, the diet of introduced P. brachypomus is mainly composed of fish remains and aquatic plants, while terrestrial plants are frequently consumed but in relatively smaller amounts. These findings show that P. brachypomus has an inherently plastic diet that can be adjusted when displaced to a novel geographic area. While trophic plasticity increases the likelihood of a species to establish breeding populations after its introduction, it also reduces our ability to predict negative effects on native species.

La introducción de peces es una práctica que se extiende globalmente y que causa perdida de especies nativas y homogenización de la diversidad dentro y entre continentes. Los estudios de dieta son herramientas útiles para definir la función ecológica de una especie introducida en un ecosistema nuevo y los posibles efectos directos e indirectos. En este estudio describimos la dieta de Piaractus brachypomus, una especie de pez Neotropical principalmente frugívora, que fue introducida en el río Sepik (Papua Nueva Guinea) hace casi dos décadas; y la comparamos con aquella de individuos de tamaño corporal similar de poblaciones nativas en las cuencas de los ríos Amazonas y Orinoco (América del Sur). En contraste con las poblaciones nativas que se alimentan principalmente de frutas y semillas, plantas e invertebrados terrestres, la dieta de individuos de P. brachypomus introducidos se compone principalmente de restos de peces y plantas acuáticas, mientras que plantas terrestres son consumidas frecuentemente pero en pequeñas cantidades. Estos resultados indican que P. brachypomus tiene una dieta plástica que puede adaptarse cuando la especie se desplaza a un área geográfica nueva. A pesar de que la plasticidad trófica aumenta la probabilidad de que una especie establezca poblaciones reproductivas después de la introducción, también reduce nuestra habilidad de predecir los efectos negativos sobre especies nativas.

Molecular identification of Cichla (Perciformes: Cichlidae) introduced in reservoirs in Southern Brazil / Identificação molecular de Cichla (Perciformes: Cichlidae) introduzidas nos reservatórios do Sul do Brasil

Species of peacock bass were introduced in several watersheds in South America and worldwide, mainly due to its importance to sport fishing, by being a fighting fish. A recent revision of the genus Cichla showed that the species introduced in reservoirs of the South, Southeast and Northeast regions of Brazil are two new species, described as Cichla kelberi (yellow peacock bass) and Cichla piquiti (blue peacock bass), erroneously identified as C. monoculus and C. ocellaris. With the purpose to identify the populations of Cichla in Paranapanema and Paraná rivers, a total of 323 base pairs (bp) of the mtDNA control region were sequenced, obtained from 84 specimens of Cichla in six different localities (Tapajós river, Solimões river, Capivara, Taquaruçu and Rosana reservoirs in the Paranapanema river, and in the upper Paraná river floodplain). The analyses revealed the genetic diversity of Cichla monoculus, introduced into the Capivara reservoir, originally from the region of Manaus (Amazonas State), and spread in the reservoirs downstream (Taquaruçu and Rosana). The occurrence of the same haplotypes in the three reservoirs suggests one single introduction. This study confirmed the introduction of Cichla in the Capivara reservoir and showed the genetic diversity of Cichla in the Paranapanema river.

Espécies de tucunaré foram introduzidas em inúmeras bacias hidrográficas da América do Sul e em outras regiões do planeta, principalmente pelas suas características esportivas, de peixe lutador. Revisão recente das espécies do gênero Cichla mostraram que as espécies que foram introduzidas nos reservatórios das regiões Sul, Sudeste e Nordeste, são duas espécies novas, descritas como Cichla kelberi (tucunaré amarelo) e Cichla piquiti (tucunaré azul) identificadas erroneamente como C. monoculus e C. ocellaris. Com o objetivo de identificar as populações de Cichla presentes no rio Paranapanema e Paraná, foram sequenciadas um total de 323 pares de bases (pb) da região controle (mtDNA) obtidas de 84 espécime de Cichla em seis localidades diferentes (rio Tapajós, rio Solimões, Reservatórios de Capivara, Taquaruçu, Rosana localizados no rio Paranapanema e na bacia do alto rio Paraná. Os dendrogramas e as análises das populações revelaram fortes evidências de que Cichla monoculus foi introduzida no reservatório de Capivara, proveniente da região de Manaus e se dispersou para os reservatórios localizados a jusante (Taquaruçu e Rosana). A ocorrência dos mesmos haplótipos nos três reservatórios sugerem uma única introdução. Este trabalho confirma a introdução de Cichla no reservatório de Capivara e revela a diversidade genética das espécies presentes no rio Paranapanema.

Germination and allometry of the native palm tree Euterpe edulis compared to the introduced E. oleracea and their hybrids in Atlantic rainforest / Germinação e alometria de Euterpe edulis comparadas à palmeira introduzida Euterpe oleracea e seus híbridos na floresta Atlântica

Palms are distinctive plants of tropics and have peculiar allometric relations. Understanding such relations is useful in the case of introduced species because their ability to establish and invade must be clarified in terms of their responses in the new site. Our purpose was to assess the survival and invasive capacity of an introduced palm species in the Atlantic rainforest, Euterpe oleracea Mart., compared to the native Euterpe edulis Mart. and to the hybrids produced between the two species. Considering this, we compared the allometry in different ontogenetic stages, the germination rates, and aspects of the initial development. The ontogenetic stages proposed for both Euterpe illustrated the growth patterns described for palm trees. E. oleracea and hybrids adjusted to the geometric similarity allometric model, while E. edulis presented a slope greater than would be expected considering this model, indicating a greater height for a given diameter. E. oleracea showed the same amount of pulp per fruit as E. edulis and a similar initial development of seedlings. The main differences observed were a lower germination rate and a faster height gain of E. oleracea seedlings. We conclude that E. oleracea, which is similar to E. edulis in aspects of allometry, development, seed and seedling morphology, may be an important competitor of this native palm tree in the Atlantic Forest.

Palmeiras são plantas características dos trópicos que apresentam relações alométricas peculiares. Compreender tais padrões pode ser útil no caso de espécies introduzidas, uma vez que sua habilidade de estabelecimento e invasão deve ser esclarecida em relação as suas respostas à nova localidade. Nosso propósito foi compreender a sobrevivência e a capacidade de invasão de uma palmeira introduzida na floresta Atlântica, Euterpe oleracea Mart. (açaizeiro) comparada à palmeira nativa Euterpe edulis Mart. (juçara), também considerando seus híbridos. Para isso comparamos suas relações alométricas em estádios ontogenéticos, sua germinação e seu desenvolvimento inicial. Os estádios ontogenéticos propostos para ambas as Euterpe ilustraram os padrões de crescimento esperados para palmeiras. E. oleracea e híbridos apresentaram-se sob o modelo alométrico de similaridade geométrica e E. edulis apresentou inclinação maior do que este modelo. E. oleracea produziu a mesma quantidade de polpa por fruto que E. edulis. As principais diferenças observadas foram menor taxa de germinação e maior velocidade de crescimento em altura para as plântulas de E. oleracea. Em conclusão, nossos resultados indicam que E. oleracea, sendo similar a E. edulis em termos de alometria, desenvolvimento e morfologia de sementes e plântulas, pode ser um importante competidor para a espécies nativa na Floresta Atlântica.

Invasion triangle: an organizational framework for species invasion.

Species invasion is a complex, multifactor process. To encapsulate this complexity into an intuitively appealing, simple, and straightforward manner, we present an organizational framework in the form of an invasion triangle. The invasion triangle is an adaptation of the disease triangle used by plant pathologists to help envision and evaluate interactions among a host, a pathogen, and an environment. Our modification of this framework for invasive species incorporates the major processes that result in invasion as the three sides of the triangle: (1) attributes of the potential invader; (2) biotic characteristics of a potentially invaded site; and (3) environmental conditions of the site. The invasion triangle also includes the impact of external influences on each side of the triangle, such as climate and land use change. This paper introduces the invasion triangle, discusses how accepted invasion hypotheses are integrated in this framework, describes how the invasion triangle can be used to focus research and management, and provides examples of application. The framework provided by the invasion triangle is easy to use by both researchers and managers and also applicable at any level of data intensity, from expert opinion to highly controlled experiments. The organizational framework provided by the invasion triangle is beneficial for understanding and predicting why species are invasive in specific environments, for identifying knowledge gaps, for facilitating communication, and for directing management in regard to invasive species.

Ichthyofauna of the Diamante stream, Caiuá Ecological Station (Diamante do Norte, Paraná State): monitoring its composition and structure - DOI: 10.4025/actascibiolsci.v31i2.3907 / Ictiofauna do ribeirão Diamante, Estação Ecológica do Caiuá (Diamante do Norte, Estado do Paraná): monitoramento de sua composição e estrutura - DOI: 10.4025/actascibiolsci.v31i2.3907

The aim of this study was to assess of composition and structure of ichthyofauna over two distinct periods: three and eleven years after the establishment of the protected area. The results of composition and structure of the ichthyofauna of the Diamante River, sampled quarterly from November 2005 to August 2006, were compared to results obtained by Abilhoa and Bastos (2005) in studies conducted between August 1997 and December 1998. The 2.4 to 16 cm-mesh gillnets were exposed for 24 hours and checked every 8 hours. In order to characterize the ichthyofauna, patterns of species richness, diversity, evenness and frequency of occurrence of species were analyzed. A total of 673 individuals, distributed among 36 species, 13 families and four orders were sampled. Significant changes were found in ichthyofauna composition, with a reduction in diversity and evenness as compared to the previous study. The high representativeness of alien species indicates instability in the studied area, through changes in diversity, species replacement, predominance of opportunistic species, and physical changes such as silting and degradation of the body of water.

O objetivo do presente trabalho foi investigar as assembleias de peixes do ribeirão Diamante (Estação Ecológica do Caiuá), visando avaliar sua composição e estrutura, ao longo de dois períodos distintos: três e 11 anos após sua criação. Para tanto, foram comparados os resultados obtidos nas amostragens realizadas trimestralmente no presente estudo, entre novembro de 2005 e agosto de 2006, com os resultados apresentados por Abilhoa e Bastos (2005) para o período de agosto de 1997 a dezembro de 1998. Neste estudo, os aparelhos de pesca foram constituídos de redes de espera simples com malhas de 2,4 a 16 cm (entre nós opostos), expostas por 24h, com revistas a cada 8h. Para a caracterização da ictiofauna, foram analisados padrões de riqueza específica, diversidade, equitabilidade e frequência de ocorrência das espécies. Foram capturados 673 indivíduos, distribuídos em 36 espécies, 13 famílias e quatro ordens. Verificou-se significativa alteração na composição da ictiofauna do ribeirão, com redução na diversidade e equitabilidade em relação ao trabalho anterior. Observou-se alta representatividade de espécies exóticas, o que indica instabilidade na área de estudo pelas alterações na diversidade, substituição de espécies, predomínio de oportunistas e alterações físicas como assoreamento e degradação do corpo de água.