Made available in DSpace on 2016-06-02T18:57:49Z (GMT). No. of bitstreams: 1 5843.pdf: 20411510 bytes, checksum: 6c8a32aab0699c1288fb33bf02ffdf15 (MD5) Previous issue date: 2014-03-17 / Financiadora de Estudos e Projetos / Digitonthophagus gazella is known worldwide because it has been introduced in tropical and subtropical regions of several countries. The aim of this introduction was to assist in the removal of dung pats in pasture areas and to aid in the biological control of flies of veterinary importance. Thus, although D. gazella has a preference for open and sunny habitats and herbaceous vegetation, there is evidence that it apparently has been adapting to closed-canopy areas. Therefore, this study aimed at evaluating the ability of D. gazella to develop in a forest environment. The study was conducted in 2012 and 2013 in the Farm of UNESP - Ilha Solteira in Mato Grosso do Sul, Brazil. To evaluate the presence of D. gazella in the forest were used pitfall traps and to verify its capability of develop in this habitat couples of this species were kept in pasture and forest fragment in the absence and presence of competitors. The results indicate that D. gazella is able to enter the forest fragment, but at short distances from the edge. Additionally, D. gazella was not able to develop and establishment in the forest fragment. / A espécie Digitonthophagus gazella é conhecida mundialmente pelo fato de ter sido introduzida em regiões tropicais e subtropicais de vários países. O objetivo dessas introduções foi o de auxiliar na remoção de massas fecais em áreas de pastagem e no controle biológico de moscas de importância veterinária. D. gazella apresenta preferência por habitats abertos e ensolarados e de vegetação herbácea, porém há indícios de que esta vem se adaptando a áreas fechadas. Com isso, este estudo objetivou avaliar a capacidade de D. gazella em se desenvolver em ambiente florestal. O estudo foi realizado nos anos de 2012 e 2013 na Fazenda de Pesquisa e Extensão da UNESP - campus de Ilha Solteira, em Selvíria/MS. Para avaliar a presença de D. gazella na mata foram utilizadas armadilhas pitfall e para verificar a capacidade de desenvolvimento um casal da referida espécie foi mantido no pasto e no fragmento florestal na ausência e presença de competidores. Os resultados indicam que D. gazella é capaz de entrar no fragmento florestal, porém a curtas distâncias da borda. E que de forma geral os indivíduos desta espécie não são capazes de se desenvolverem e se estabelecerem no fragmento florestal.

Orientador: Marcos Nogueira / Coorientador: Mario Luis Orsi / Banca: Fausto Foresti / Banca: Sirley F. Bennemann / Resumo: O Reservatório da UHE Escola Mackenzie (Represa de Capivara) Rio Paranapanema foi constituído em 1977 e representa o maior reservatório em extensão e volume ocupado na bacia hidrográfica do Rio Paranapanema e nas primeiras décadas (80 e 90) após sua formação foi palco de constantes introduções acidentais e intencionais dos mais diversos organismos, sendo uma destas espécies a Cichla monoculus. Neste contexto, diversos pesquisadores concluíram que espécies do gênero Cichla representam importante impacto à bacia do alto Rio Paraná onde foi introduzida, o que originou a presente proposta desse estudo. O objetivo central desse projeto foi realizar uma análise do processo de introdução da espécie Cichla monoculus no reservatório de Capivara, como forma de avaliar biologicamente se a mesma pode ser considerada como uma invasora ―latu senso‖. Foram compilados dados de captura dos anos de 1991 a 1999 (relativos ao projeto Tibagi, trecho reservatório). E as coletas relativas a este estudo foram realizadas trimestralmente correspondendo ao período de outono de 2001 a verão de 2002, outono de 2002 a verão de 2003 e outono de 2009 a verão de 2010 finalizando 3 ciclos (I, II e III, respectivamente). Os resultados nos possibilitaram verificar que após 3 anos da primeira introdução da espécie (1997 a 1998), a mesma já alcançou proporções de abundancia equivalente as nativas e com acréscimo populacional subseqüente até 2003, com forte indicativo de um processo de estabelecimento e conseqüente invasão no reservatório, com modesta depleção durante o ultimo ciclo de estudo (Ciclo III). Os dados de densidade (CPUEn) demonstram uma tendência ao decréscimo e o comprimento padrão médio não apresentou alterações significativas. A proporção sexual apresentou grande... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The UHE Escola Mackenzie (Capivara Reservoir) Paranapanema River, was build in 1977 and nowadays is de biggest reservoir in extension and volume in the Paranapanema River Basin. In the first two decades after your construction occurred several introduction (accidental or on purpose) of none native fishes in this area. One of this species was Cichla monoculus. In this context, several researches concluded that species belonging to the Cichla gender cause important impact to the Parana River Basin where it has been introduced. The idea of this project came from these observations. The aim of this study was to analyze the introduction process of the species Cichla monoculus in the Capivara reservoir and to evaluate biologically if this species is established or not in the reservoir. Data from an old project realized in the same area was used covering a period from 1991 to 1999 (Tibagi Project). The samples related to this study were spread in three different cycles (I, II and III): autumn 2001 to summer 2002, autumn 2002 to summer 2003 and autumn 2009 to summer 2010, respectively. The data shown that three years after the C. monoculus accidental escaping the species reach abundance proportions equivalent to de native species and further increase to 2003, indicating a establishment process and consequent invasion of the reservoir system, with small depletion during the last cycle (Cycle III). The CPUEn shown a decrease tendencies and the standard length did not present significant alterations. The sexual proportion presents variations and was attributed to the environmental factors. During the study, juveniles were sampled mainly (86.98% Cycle I; 81.81% Cycle II e 83.84% Cycle III) indicating a recruitment success. More than 55% of the specimens collected were between 6 to 11 centimeters of standard... (Complete abstract click electronic access below) / Mestre

Les modèles climatiques prédisent une augmentation globale de la température de 1 à 4°C d’ici 2100. Les modifications de climat engendrées par ce réchauffement devraient favoriser les invasions biologiques. L’objectif général de cette thèse est d’explorer l’impact du réchauffement et du changement climatique sur quatre espèces de macrophytes invasifs en Europe. Le travail réalisé a porté sur la germination, la croissance, la physiologie et la distribution des ces espèces à travers des expérimentations en conditions contrôlées, en jardin expérimental, et via des modèles de distribution d’espèces. Nous avons montré que i) des températures plus élevées améliorent modérément les capacités de germination de Ludwigia hexapetala et Ludwigia peploides subsp. montevidensis, diminuent la survie des plantules mais augmentent leur production de biomasse, ii) l’effet d’une augmentation de température sur les macrophytes dépend de la saison à laquelle elle a lieu, iii) une augmentation de 3°C peut avoir des conséquences sur le métabolisme sans pour autant affecter la croissance, iv) la Jussie L. hexapetala est la seule espèce qui a de meilleures capacités de croissance à la fois apicale et latérale face à un réchauffement, v) les modèles prédisent une augmentation de l’aire de distribution de Ludwigia spp., Myriophyllum aquaticum et E. densa dans leurs aires d’invasion, et une diminution de leur distribution sur les autres continents, y compris dans leur aire d’indigénat. Ce travail permet de mieux comprendre les conséquences possibles des modifications climatiques sur les macrophytes invasifs, afin d’appréhender et d’anticiper leur potentiel de colonisation futur. / Climatic models predict a rise of globale surface temperature about 1 to 4°C by 2100. Climate modifications generated by this warming might favor biological invasions. The general objectif of this thesis was to explore the impacts of climate warming and climate change on four macrophytes invasive in Europe. This work focused on germination, growth, physiology and distribution of these species, through experiments in controlled conditions, in experimental garden and by using species distribution models. We showed that i) higher temperatures favor moderately the germination capacity of Ludwigia hexapetala and Ludwigia peploides subsp. montevidensis, decrease the seedlings survivorship but improve their biomass production, ii) the effect of increased temperature on macrophytes depends on the season, iii) a 3°C warming can modify metabolism without generating changes on the growth, iv) the water primroses L. hexapetala is the only species that showed both better apical and lateral growth when facing a warming, v) models predict an increase of the distribution surface of Ludwigia spp., Myriophyllum aquaticum and E. densa in their invasive ranges, and a decrease of their distribution area in the other continents, including their native range. This thesis offer a better understanding of climate changes consequences on invasive macrophytes in order to anticipate their futur colonisation potential.

Les invasions biologiques étant des processus raisonnablement limités dans le temps et l’espace, elles fournissent un cadre propice à l’étude de modèles complexes par simulation numérique. Nous mettons à profit la méthode de Calcul Bayésien Approché (ABC) pour étudier l’invasion du frelon asiatique (Vespa velutina), en estimant les paramètres d’un modèle probabiliste démographique et génétique spatialement explicite. La croissance des populations dans chaque unité paysagère est décrite par une fonction des conditions environnementales locales, tandis que les flux migratoires entre populations sont tirés dans des lois dont les densités sont fonctions de la distance géographique à parcourir. Certains paramètres de ces fonctions sont inconnus et doivent être estimés. Conditionnellement à la démographie, un processus de coalescence permet de simuler l’histoire génétique de l’échantillon. Une fois la simulation achevée, la procédure ABC permet de accepter/rejeter les valeurs de paramètres en fonction de la plausibilité des données génétiques qu’ils permettent de générer. La comparaison de modèles étant une étape clé de la méthodologie ABC, cela impose que différentes versions de simulateurs de coalescence puissent être rapidement développées. A cette fin, cette thèse propose Quetzal, une bibliothèque assez générale pour pouvoir aisément s’adapter à un grand nombre de modèles possibles, et qui inclue des algorithmes originaux et génériques. Les principaux concepts de programmation permettant d’utiliser et d’étendre Quetzal sont également exposés à travers les différents chapitres. Enfin, nous mettons à profit les particularités du contexte d’étude du frelon asiatique pour développer une méthodologie spécifique reposant sur le formalisme des partitions floues et qui permet, en recentrant l’analyse sur les processus démographiques très récents, de réduire le nombre d’hypothèses, le nombre de paramètres et le coût simulatoire de l’analyse. / Because biological invasions are processes well delimited in both space and time, they offer a unique framework in which complex models can be studied by numerical simulations. We use the Approximated Bayesian Computation method (ABC)to study the Vespa velutina invasion, estimating the parameters of spatially explicit demographic and genetic probabilistic model. The population growth in each landscape unit is described by a function of the local environmental features, whereas the migration flux between populations are sampled in laws which densities are functions of the geographical distance. Some of the parameters of these functions are unknown and should be estimated. Conditionally to the demography, a coalescence process allows for simulating the genetic history of the sample. Once the simulation done, the ABC method allows for accepting/rejecting the parameters values as a function of the data plausibility they generate. Models comparison is a key step in ABC methodology: this requires that various versions of coalescence-based simulators can be quickly developed. To this end, this thesis offers Quetzal, a library general enough to be easily adapted to an open-ended number of models variants. It includes original and generic algorithms. The main programming concepts required to use and extend Quetzal are presented through the various chapters. Finally, we take advantage of the biological context to develop a specific methodology built on the fuzzy partitions formalism. It allows to focus only on the very recent demographic processes, and consequently to reduce the number of hypothesis,the number of parameters, and the simulation cost of the analysis.

La question de la coexistence entre espèces est cruciale dans le contexte des changements globaux, où certaines espèces colonisent de nouveaux écosystèmes, tel le cas des espèces invasives. Dans les habitats discontinus, la coexistence entre espèces invasives et natives gagne à être considérée à la lumière de la théorie des métacommunautés, et en particulier en examinant séparément les processus de dispersion et les interactions locales afin de déterminer leurs effets relatifs. Les approches observationnelles en milieux naturels permettent par ailleurs la prise en compte de la complexité des relations possibles. C’est le travail abordé dans cette thèse à travers l’exemple de l’effet de l’invasion de l’écrevisse de Louisiane sur les amphibiens natifs dans des réseaux de mares. La densité des larves et la distribution des amphibiens ont montré la conccurrence avec l’écrevisse dans les mares. Grâce à la génétique du paysage, la dispersion de l’écrevisse s’est révélée fortement contrainte par le caractère discontinu des habitats, contrairement à celle des amphibiens, bien qu’elle ait été variable parmi les trois espèces étudiées. Les analyses d’isotopes stables ont montré que malgré sa position centrale dans les réseaux trophiques, l’écrevisse n’avait pas de fortes interactions trophiques avec les amphibiens, tout au plus un effet indirect par la modification de l’habitat. Sur la base des mécanismes considérés ici, la coexistence entre les amphibiens natifs et l’écrevisse invasive semble ainsi envisageable. Des suites de ce travail sont envisageables à l’échelle des communautés grâce à l’ADN environnemental. / The question of species coexistence is crucial in the context of global changes, where some species colonize new ecosystems, such as the case of invasive species. In patchy habitats, the coexistence between invasive and native species gains at being considered in the light of the metacommunity theory, and particularly by examining separately the processes of dispersal and local interactions to determine their relative effects. Besides, observational approaches in natural habitats allow to account for the complexity of the possible relationships. It is the work tackled in this thesis through the example of the effect of the red swamp crayfish on native amphibians in pond networks. The density of larvae and the distribution of native amphibians showed the co-occurrence with the crayfish in ponds. Owing to landscape genetics, the dispersal of crayfish was shown to be highly constrained by the patchy nature of habitats, contrary to that of amphibians, although it was variable among the three species considered. The stable isotope analyses showed that, despite its central position in the food webs, the crayfish did not have strong trophic interactions with amphibians, all the more an indirect effect through habitat modification. On the basis of the mechanisms considered here, the coexistence between native amphibians and the invasive crayfish seem possible. Perspectives from this work are envisaged at the community scale using environmental DNA.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19529号 / 理博第4189号 / 新制||理||1601(附属図書館) / 32565 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 大串 隆之, 教授 中野 伸一, 教授 曽田 貞滋 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Resumo parte 1: A invasão biológica é uma das principais ameaças à biodiversidade em todo o mundo. Entretanto, apesar dos trópicos concentrarem a maior parcela desta diversidade, ainda é pouco e esparso o conhecimento científico disponível sobre plantas invasoras nos ecossistemas tropicais. Este capítulo tem como objetivo comparar a quantidade de trabalhos publicados sobre invasões biológicas por plantas terrestres em ambientes tropicais e não tropicais, assim como a abordagem seguida nesses artigos. Foram lidos, selecionados e revisados os artigos publicados no intervalo de 1995 a 2004, em oito revistas científicas de alto índice de impacto. Ao todo, foram encontrados 239 artigos sobre plantas invasoras, sendo que a maioria deles aborda ecossistemas da América do Norte e Europa. Este é um reflexo do desequilíbrio na produção científica atual, que não dá a devida atenção aos ambientes com a maior biodiversidade, sendo que esta recebe vários tipos de ameaças à sua conservação. Resumo parte 2: As palmeiras da espécie Archontophoenix cf. cunninghamiana são invasoras em um pequeno fragmento florestal na região metropolitana da cidade de São Paulo (SP). Este trabalho investigou a abundância das sementes dessa espécie na chuva e no banco de sementes nesse local. Foram coletadas cinqüenta amostras de solo e de sementes da chuva de sementes em doze coletas mensais. Os resultados indicam que a dispersão de sementes dessa espécie invasora é efetiva na mata e que há a possibilidade dessa espécie formar um banco de sementes sazonal. Portanto, o sucesso da invasão poderia ser explicado pela capacidade de dispersão dessa espécie na mata, assim como por outras características da espécie e pela baixa resistência à invasão da comunidade neste fragmento. / Biological invasion is one of the worst threats to the world biodiversity. The actual extent of the impact of biological invasions in the tropics is still unknown. The aim of this chapter is to survey the literature published on plant invasions, comparing the material concerning the tropics with that regarding the rest of the world. 239 articles published in 8 ecological journals over the past ten years were reviewed. Most of them focused on temperate ecosystems, in North America and Europe. There is a weak effort on research concerning plant invasions in tropical ecosystems. Much more research is needed to evaluate the real scenario in the countries that contain the highest biodiversity of the world. The exotic palm Archontophoenix cf. cunninghamiana invaded a small forest fragment in São Paulo (São Paulo, Brazil). The abundance of this species in the seed rain and seed bank were investigated. The results indicate that this species may form a seasonal seed bank in the soil and that the seed dispersal is effective in the community. The success of the invasion by this exotic palm can be attributed to its high dispersal ability and to the community high invasibility due to the isolation of the forest fragment.

Invasões biológicas são uma das maiores ameaças à biodiversidade mundial. O estabelecimento de espécies exóticas, principalmente de insetos, em vários países ocorreu por meio da utilização de controle biológico, quando se introduz uma espécie exótica para o controle de outra. Em alguns casos, por diferentes motivos, espécies introduzidas com este objetivo acabaram se tornando invasoras. O besouro coprófago Digitonthophagus gazella é um destes exemplos. O objetivo desta tese foi avaliar o impacto de D. gazella sobre a abundância, diversidade e turnover de uma comunidade de besouros coprófagos nativos no Brasil. A comunidade foi amostrada semanalmente, e no mesmo local, desde novembro de 1989, através de armadilha luminosa, obtendo-se dados até novembro de 2015. A espécie exótica invadiu a área após quatro anos do início das coletas, tendo-se no presente estudo 22 anos de coletas semanais dessa espécie exótica introduzida. Na comunidade já havia outra espécie coprófaga exótica presente, Labarrus pseudolividus, que possui hábito residente de nidificação. A invasão por D. gazella modificou substancialmente a comunidade local. A abundância, diversidade e riqueza da comunidade nativa apresentavam tendência de aumento antes, passando a diminuir após a invasão. As espécies com o mesmo hábito de nidificação de D. gazella (escavador) não mostraram sinais de recuperação dos impactos, com todos os índices apresentando decréscimo contínuo desde a invasão, principalmente do turnover, tamanho populacional e riqueza de espécies. Espécies residentes, exibindo hábito similar a L. pseudolividus, foram capazes de recuperar o status após alguns anos, mantendo-se mais estáveis a partir do ano 15. Quando analisado o turnover da comunidade atual, ou seja, espécies nativas e exóticas, observou-se que toda a dinâmica da comunidade foi mantida pelas espécies exóticas. A partir da diminuição da abundância de D. gazella houve aumento na de L. pseudolividus, levando a uma aparente estabilidade na diversidade e turnover, a despeito do comportamento oposto observado na comunidade nativa. A partir da invasão por D. gazella, variáveis climáticas, fatores responsáveis principais pela característica da comunidade, passaram a execer menor influência. / Biological invasions are one of the major threats to the global biodiversity. The use of exotic species as agents of biological control is one way to contribute to invasions. In some cases, the introduced species became invasive. The tunneler dung beetle (DB) Digothophagus gazella is a good example. Released in many countries, including Brazil, to improve dung pad removal, the species quickly spread to new ones, where it is considered as an invasive species. The objective of this thesis was to evaluate impacts of D. gazella on the abundance, alfa-diversity and turnover of a native DB community in Brazil. Another exotic DB species, the dweller Labarrus pseudolividus, was present in the study area. The community was sampled weekly, at the same location, from November 1989 until November 2015 using a black light trap. The exotic species was first recorded four years after the beginning of sampling. The invasion by D. gazella changed significantly the native community. Abundance, diversity and richness were increasing during the first years, however they all decreased since the invasion. Species with the same nesting behavior of D. gazella (tunneler) were not able to recover from the impacts, with turnover, abundance and species richness continuously decreasing after the invasion. Dweller species on the contrary were able to partially recovery after some years, rebound its abundance and turnover since year 15. Results from the turnover analysis of the current community, which is native and exotic, showed that it has been influenced by both exotic species. Following the decrease in abundance of D. gazella and native species, L. pseudolividus was able to increase its abundance, leading to stabilization of the turnover despite the opposite observed in the native community. Since the invasion by D. gazella, weather variables became less important on the changes observed.

Nos cerrados brasileiros, várias gramíneas africanas foram introduzidas, tornando-se invasoras e ameaçando a biodiversidade nativa. É, portanto, imprescindível a elaboração de medidas para seu controle. O objetivo deste estudo foi avaliar a eficiência e o custo de diferentes métodos para o controle das gramíneas invasoras Urochloa decumbens e Melinis minutiflora, em unidades de conservação de proteção ao cerrado. O trabalho foi desenvolvido no Cerrado Péde- Gigante e na Estação Ecológica de Itirapina (SP, Brasil), onde foram selecionadas seis manchas com dominância de U. decumbens e seis com M. minutiflora. Em cada mancha, aplicou-se um bloco randômico com os tratamentos: corte raso, uma vez (CRI, nov/2007) e duas vezes (CRII, nov/2007 e mar/2008), corte e revolvimento do solo, uma vez (CRSI, nov/2007) e duas vezes (CRSII, nov/2007 e mar/2008), sombreamento (SOM), abafamento (ABF), estes aplicados em julho/2007, permanecendo cobertos respectivamente com tela de nylon e lona até mar/2008. Ao final do experimento (jul/2008), a biomassa das parcelas foi cortada e separada em categorias (graminóides nativas, U. decumbens, M. minutiflora, dicotiledôneas). As análises basearam-se em testes de permutação. Posteriormente, foram calculados os custos de cada tratamento com mão-de-obra, materiais, ferramentas, transporte e descarte para o manejo das áreas. Para U. decumbens, os tratamentos mais eficientes para reduzir sua biomassa foram ABF, CRII e CRSII, sendo o ABF economicamente viável apenas para manejo de pequenas infestações; para áreas maiores, os tratamentos de corte mostram uma melhor relação benefício/custo. Para M. minutiflora, ABF, CRII, CRSII e CRSI são eficientes em reduzir sua biomassa e o tratamento CRSI é o que possui maior relação benefício/custo, portanto, o mais viável para o controle de desta gramínea. / Several African grasses introduced in the Brazilian savannas for cattle feeding became invasive, and now they severely threaten the native biodiversity. It is, therefore, fundamental to look for effective methods to control them. The objective of this study was to evaluate the efficiency and cost of different management techniques to control the invasive grasses Urochloa decumbens and Melinis minutiflora. The study was conducted in the Cerrado Pé-de-Gigante and Itirapina Ecological Station (SP, Brazil). Six plots dominated by U. decumbens and six by M. minutiflora were selected and a random block design was applied including the treatments: clipping once ( CRI, nov/2007) and twice (CRII, nov/2007 and mar/2008), clipping and soil digging once (CRSI, nov/2007) and twice (CRSII, nov/2007 and mar/2008), shading (SOM), mugging (ABF), being the last two applied in July/2007 and remained covered until mar/2008, respectively with nylon mesh and canvas. At the end of the experiment (jul/2008), all biomass in the blocks was cut and separated into categories (native grasses, U. decumbens, M. minutiflora and dicotyledons). The analyses were based on permutation tests. The cost of each treatment was calculated taking into account materials, tools, labor, transportation and discharge. The most effective treatments to reduce U. decumbens biomass were ABF, CRII and CRSII, being ABF economically viable only for small patches; the double-clipping treatments showed best benefit/cost value in large areas. The treatments ABF, CRII, CRSI and CRSII were effective in reducing M. minutiflora biomass, being CRSI the one which showed a best benefit/cost value; therefore, clipping and digging is the best way to control that grass.

Biological invasions of non-native species are one of the most serious factors threatening global biodiversity. Their negative impacts are particularly evident in the case of freshwater ecosystems and native crayfish populations that live there. Generally, the higher dominance of non-native crayfish species over the native species is relatively well known, but the interactions between non-native crayfish species are significantly less investigated. Although their distribution is increasingly more important and it is obvious that non-native crayfish species will dominate in European waters. However, it is not yet clear which of these crayfish will be more successful. The aim of this diploma thesis was to create a literature review on the topic of interspecific interactions in crayfish with emphasis on native and non-native crayfish species occurring in Europe. The experimental part of the thesis was focused on the comparison of direct interactions and competition for shelter between the widespread spiny-cheek crayfish Faxonius limosus (Rafinesque, 1817) and the newly increasingly occurring marbled crayfish Procambarus virginalis Lyko, 2017. These species are becoming increasingly common in the European wild, but about their mutual direct interactions and competition is largely unknown. During agonistic interactions the marbled crayfish won in significantly more fights than the spiny-cheek crayfish in the absence as well as presence of the shelter. The marbled crayfish established a significantly greater dominance over the females of the spiny-cheek crayfish in the absence and in the presence of shelter, but not over the males. It is also important to say that the presence of the shelter reduces the number of fights and their total duration. There was no significant difference in dominance established by occupation of shelter between the marbled crayfish and the spiny-cheek crayfish. Still, thanks to its aggressiveness, marbled crayfish is able to compete with other non-native species or displace them from freshwater ecosystems.