Predation On Native Anurans By Invasive Vertebrates In The Atlantic Rain Forest, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)203 Specia lissue7074161812/2011-2, CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico303776/ 2015-3, CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico3855/13-9, CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Introdução de peixes em ecossistemas continentais brasileiros: revisão, comentários e sugestões de ações contra o inimigo quase invisível

The introduction of species is a major threat to the conservation of biodiversity, being the main precursor of a prominent global biotic homogenization. In the case of perception, control or eradication, aquatic species are among the most problematic. In this sense, fish introductions become serious threats because these organisms are very widespread, mobile and of difficult perception and/or detection by the society. In the early stages of introduction, they may be considered “invisible” (e.g. less exposed than the majority of the introduced organisms, especially terrestrial organisms). Thus, it is common fact that introductions of this group of organisms are perceived only when they are already in advanced stages of the invasion process and the damage is irreversible. A species of fish can be considered non-native, even at the level of basins or sub-basins. This makes the perception or detection of introduced fish even more complex in Brazil, due to its continental dimensions and rich continental aquatic environments. Often, the cultural aspects and time of release contribute to the “invisibility” of the problem. Even fish coming from other continents, such as carp, tilapia and trout are incorporated in the country for so long that they are considered “native”. Even in the scientific field the theme is under-explored in Brazil, but information about problems that may arise from biological invasions is building up. Indeed, not all introductions have catastrophic consequences, but many do. However, we can understand older impacts and detect new ones in the near future if we want to do so. In view of the exposed, and given the magnitude of the problem, and disproportion in the search for answers and impacts, a review of the theme with suggestions for actions is presented. Key words: introduction of species, threats, non-native species, biological invasions, biodiversity, aquatic ecosystems.A introdução de espécies é uma grande ameaça para a conservação da diversidade biológica, e a principal precursora da homogeneização global. Em se tratando de percepção, controle ou erradicação, espécies aquáticas encontram-se entre as mais problemáticas. Neste sentido, os peixes tornam-se graves ameaças, pois são organismos muito disseminados, móveis e de difícil percepção por parte da sociedade. Nas fases iniciais da introdução, peixes não-nativos podem ser considerados ameaças “invisíveis”, pois são menos expostos que a maioria dos organismos introduzidos, principalmente os terrestres. Assim, se torna comum que introduções deste grupo sejam percebidas apenas quando já se encontram em estágios avançados e os danos são irreversíveis. Também é imprescindível se compreender que uma espécie de peixe pode ser considerada não-nativa, numa mesma bacia ou sub-bacia hidrográfica. Isto torna a percepção ou detecção de peixes introduzidos ainda mais complexa no Brasil, devido a suas dimensões continentais e riqueza de ambientes. Aspectos culturais e tempo de introdução contribuem para a “invisibilidade” do problema. Mesmo peixes advindos de outros continentes, como as carpas e tilápias, já se encontram incorporados há tanto tempo no país, que são considerados “nativos” por algumas comunidades ribeirinhas e/ou ignorados pela população. No campo científico o tema das introduções ainda é sub-explorado no Brasil, mas as informações sobre problemas estão crescendo. Nem todas as introduções causam problemas, mas muitas causam. Além dos problemas ecológicos de curto prazo, introduções podem estar causando mudanças que só serão percebidas em longo prazo. Em vista da magnitude do problema e da discrepância entre o número de introduções e a busca por suas consequências ou impactos é feita uma revisão sobre o tema com comentários e sugestões de ações prioritárias e urgentes. Palavras-chave: introdução de espécies, ameaças, espécies não nativas, invasões biológicas, biodiversidade, ecossistemas aquáticos

Structuring evidence for invasional meltdown: broad support but with biases and gaps

Negative interactions have been suggested as a major barrier for species arriving in a new habitat. More recently, positive interactions drew attention from community assembly theory and invasion science. The invasional meltdown hypothesis (IMH) introduced the idea that positive interactions among non-native species could facilitate one another’s invasion, even increasing their impact upon the native community. Many studies have addressed IMH, but with contrasting results, reflecting various types of evidence on a multitude of scales. Here we use the hierarchy-of-hypotheses (HoH) approach to differentiate key aspects of IMH, organizing and linking empirical studies to sub-hypotheses of IMH. We also assess the level of empirical support for each sub-hypothesis based on the evidence reported in the studies. We identified 150 studies addressing IMH. The majority of studies support IMH, but the evidence comes from studies with different aims and questions. Supporting studies at the community or ecosystem level are currently rare. Evidence is scarce for marine habitats and vertebrates. Few sub-hypotheses are questioned by more than 50% of the evaluated studies, indicating that non-native species do not affect each other’s survival, growth, reproduction, abundance, density or biomass in reciprocal A ↔ B interactions. With the HoH for IMH presented here, we can monitor progress in empirical tests and evidences of IMH. For instance, more tests at the community and ecosystem level are needed, as these are necessary to address the core of this hypothesis

Invasive aquatic pets: failed policies increase risks of harmful invasions

Businesses in the pet trade collect and transport many aquatic species around the globe, and some of these individuals are released into new habitats. Some jurisdictions have introduced laws intended to regulate this trade, but these regulations have rarely had the desired effects. Laws regarding pets and the pet trade are often poorly communicated, poorly enforced, and not aligned with hobbyists’ beliefs. Consequently, some laws may increase the number of unwanted introductions instead of decreasing them. A significant change in approach is needed, involving far greater communication with scientists, administrations, politicians, the pet industry, and pet owners, promoting euthanasia of unwanted pets rather than release, and the creation and promotion “white lists” of low risk species that can be sold in the pet trade

The genetic characteristics of invasive Largemouth Bass in southern Brazil

Largemouth Bass (Micropterus salmoides) have been introduced on a global scale for sport fishing but represent a conservation concern given their documented negative impacts on native faunal diversity and abundance. Recent research using molecular data to characterize invasive Largemouth Bass populations elsewhere has demonstrated that populations are typically characterized by limited genetic diversity, or represent a combination of Largemouth Bass and Florida Bass (Micropterus floridanus). To test whether these traits were consistent with invasive populations in Brazil, we generated mitochondrial sequence data from four established populations of Largemouth Bass collected in southern Brazil as well as a local aquaculture facility to confirm species identity and quantify levels of genetic diversity. We identified the exclusive presence of Largemouth Bass in the region and observed limited levels of haplotype (haplotype diversity = 0.0684, SE = 0.038) and nucleotide diversity (0.0003, SE = 0.0002) which suggested the presence of a founder effect associated with introduction. Each of the four populations were dominated by a single haplotype that was identical to one recovered from a nearby aquaculture facility, which identified this facility as a potential introduction source

Ecologia alimentar do lambari, Deuterodon langei Travassos, 1957 (Characidae, Tetragonopterinae), de diferentes tamanhos em um riacho da Floresta Atlântica, Paraná (Brasil)

Estudos sobre a alimentação de uma determinada espécie geralmente resultam em uma contribuição para o conhecimento da mesma e são fundamentais para a compreensão do funcionamento do ecossistema do qual esta faz parte. O presente trabalho buscou ampliar o conhecimento sobre a ecologia alimentar de Deuterodon langei Travassos, 1957, por meio de análises sobre a composição da dieta, partilha de recursos, estratégia alimentar e o papel dos componentes intra- e inter-individuais na amplitude do nicho alimentar da espécie, enfocando variações entre diferentes classes de comprimento num mesmo intervalo temporal e espacial. A dieta de D. langei foi considerada de um modo geral como onívora, apesar da notável diminuição dos itens animais e concomitante aumento da importância de itens de origem vegetal durante o processo ontogenético. Foi constatada a existência de diferentes estratégias alimentares e de uma certa partilha de recursos entre as diferentes classes de comprimento. ABSTRACT Studies on feeding behaviour in general contribute significantly for the knowledge about the biology of the species, and are crucial for the understanding functional relations within the ecosystem in which the species is inserted. The present study aimed the knowledge about the feeding ecology of Deuterodon langei Travassos, 1957, through analyses of diet composition, resource partitioning, feeding strategies, and the role of intra- and inter-individual components on the determination of the amplitude of the species´ feeding niche. The study was conducted focusing on variations between different size classes within a same time and space interval. The diet of D. langei was in general considered omnivorous despite the remarkable reduction in animal items and concomitant increase in vegetal items during ontogenesis. Different feeding strategies and a certain degree of resource partitioning between different size classes of this species was thus detected. RESUMÉ Des récherches sur la nourriture concourent pour la connaissance des espèces et sont rélevants pour la compréhension du fonctionnement de lécosystème. On a déterminé dans ce travail la composition du régime de nourriture de Deuterodon langei Travassos, 1957, la partage de ressources, la stratégie de la nourriture et le rôle des composantes intra et interindividuales dans lamplitude du créneau alimentaire de lespèce, en focalisant variations entre des classes différentes de longueur dans un même intervalle temporal et spatial. Le régime de D. langei est omnivore, malgré la remarquable réduction des itens animaux et augmentation de la rôle de itens végétales pendant son développement ontogénétique. On a été constatée lexistence de différentes stratégies de nourriture et de partage de ressources entre les différentes classes de longueur

Predation risk by largemouth bass modulates feeding functional responses of native and non-native crayfish

Context-dependency is prevalent in nature, challenging our understanding and prediction of the potential ecological impacts of non-native species (NNS). The presence of a top predator, for example, can modify the foraging behaviour of an intermediate consumer, by means of non-consumptive effects. This raises the question of whether the fear of predation might modulate consumption rates of NNS, thus shaping the magnitude of ecological impacts. Here, we quantified the functional feeding responses of three non-native crayfish species – red swamp crayfish Procambarus clarkii, rusty crayfish Faxonius rusticus and virile crayfish Faxonius virilis – compared to the native analogue signal crayfish Pacifastacus leniusculus, considering the predation risk imposed by a top fish predator, the globally invasive largemouth bass Micropterus salmoides. We applied the comparative functional response (FR) approach using snails as prey and exposing crayfish to water containing predator and dietary chemical cues or not. All crayfish species presented a destabilising Type II FR, regardless of the presence of chemical cues. Predation risk resulted in significantly longer handling times or lower attack rates in non-native crayfish; however, no significant differences were observed in signal crayfish. We estimated per capita impacts for each species using the functional response ratio (FRR; attack rate divided by handling time). The FRR metric was lower for all crayfish species when exposed to predation risk. Rusty crayfish demonstrated the highest FRR in the absence of chemical cues, followed by signal crayfish, virile crayfish and red swamp crayfish. By contrast, the FRR of signal crayfish was nearly twice that of rusty crayfish and virile crayfish and ten times greater than red swamp crayfish when chemical cues were present. The latter result agrees with the well-recognised ecological impacts of signal crayfish throughout its globally-introduced range. This study demonstrates the importance of considering the non-consumptive effects of predators when quantifying the ecological impacts of intermediate non-native consumers on prey. The direction and magnitude of the modulating effects of predators have clear implications for our understanding of NNS impacts and the prioritisation of management actions