Global drivers of the conservation-invasion paradox.

The conservation-invasion paradox (CIP) refers to a long-term phenomenon wherein species threatened in their native range can sustain viable populations when introduced to other regions. Understanding the drivers of CIP is helpful for conserving threatened species and managing invasive species, which is unfortunately still lacking. We compiled a global data set of 1071 introduction events, including 960 CIP events (successful establishment of threatened species outside its native range) and 111 non-CIP events (unsuccessful establishment of threatened species outside its native range after introduction), involving 174 terrestrial vertebrates. We then tested the relative importance of various predictors at the location, event, and species levels with generalized linear mixed models and model averaging. Successful CIP events occurred across taxonomic groups and biogeographic realms, especially for the mammal group in the Palearctic and Australia. Locations of successful CIP events had fewer native threat factors, especially less climate warming in invaded regions. The probability of a successful CIP event was highest when species introduction efforts were great and there were more local congeners and fewer natural enemies. These results can inform threatened species ex situ conservation and non-native invasive species mitigation.

Causantes mundiales de la paradoja conservación­invasión Resumen La paradoja de conservación­invasión (PCI) se refiere al evento a largo plazo en el que las especies amenazadas en su distribución nativa puedan mantener poblaciones viables cuando se les introduce a otras regiones. Es de mucha ayuda para la conservación de especies amenazadas y el manejo de especies invasoras entender las causantes de la PCI, entendimiento que todavía es escaso. Compilamos un conjunto mundial de datos de 174 vertebrados terrestres en 1071 eventos de introducción, incluyendo 960 eventos de PCI (el establecimiento exitoso de especies amenazadas fuera de su distribución nativa) y 111 eventos no PCI (el fracaso en el establecimiento de especies amenazadas fuera de su distribución nativa después de la introducción). Después analizamos con modelos lineales mixtos generalizados y promedio de modelos la importancia relativa de varios pronosticadores en la localidad, en el evento y a nivel de especie. Los eventos exitosos de PCI ocurrieron en todos los grupos taxonómicos y en todos los reinos biogeográficos, especialmente para los mamíferos del Paleártico y Australia. Las localidades de los eventos exitosos de PCI tuvieron menos factores nativos de amenaza, especialmente un menor calentamiento climático en las regiones invadidas. La probabilidad de que un evento de PCI sea exitoso fue mayor cuando los esfuerzos de introducción fueron mayores y hubo más congéneres locales y menos enemigos naturales. Estos resultados pueden orientar la conservación ex situ de especies y la mitigación de especies invasoras no nativas.

Resolving whether botanic gardens are on the road to conservation or a pathway for plant invasions.

A global conservation goal is to understand the pathways through which invasive species are introduced into new regions. Botanic gardens are a pathway for the introduction of invasive non-native plants, but a quantitative assessment of the risks they pose has not been performed. I analyzed data on the living collections of over 3000 botanic gardens worldwide to quantify the temporal trend in the representation of non-native species; the relative composition of threatened, ornamental, or invasive non-native plant species; and the frequency with which botanic gardens implement procedures to address invasive species. While almost all of the world's worst invasive non-native plants occurred in one or more living collections (99%), less than one-quarter of red-listed threatened species were cultivated (23%). Even when cultivated, individual threatened species occurred in few living collections (7.3), while non-native species were on average grown in 6 times as many botanic gardens (44.3). As a result, a botanic garden could, on average, cultivate four times as many invasive non-native species (20) as red-listed threatened species (5). Although the risk posed by a single living collection is small, the probability of invasion increases with the number of botanic gardens within a region. Thus, while both the size of living collections and the proportion of non-native species cultivated have declined during the 20th century, this reduction in risk is offset by the 10-fold increase in the number of botanic gardens established worldwide. Unfortunately, botanic gardens rarely implement regional codes of conduct to prevent plant invasions, few have an invasive species policy, and there is limited monitoring of garden escapes. This lack of preparedness is of particular concern given the rapid increase in living collections worldwide since 1950, particularly in South America and Asia, and highlights past patterns of introduction will be a poor guide to determining future invasion risks.

Produção do mangarito em função do tamanho do rizoma-semente / Tannia yield in function of size seed-rhizomes

O objetivo deste trabalho foi avaliar a resposta produtiva do mangarito em função de diferentes tamanhos de rizomas-semente. O delineamento experimental utilizado foi de blocos casualizados com três tipos de rizomas-semente (rizoma mãe, rizoma filho 1 e rizoma filho 2) e sete repetições. A parcela experimental foi composta por 16 plantas, sendo avaliadas as oito plantas centrais. Foram avaliadas as seguintes características: massa fresca total, produção líquida e produção comercial. Verificou-se que a produção total, líquida e de rizoma-mãe e filho foi maior ao usar como semente o rizoma-mãe; no entanto, a produção comercial do rizoma-mãe foi estatisticamente igual à do rizoma filho 1. Recomenda-se o cultivo de Xanthosoma mafaffa Schott usando como semente propágulos de rizoma-mãe por apresentar uma maior produção e por não ser comercializável.

The aim of this work was to evaluate the productive response of the tannia in function of different sizes of seed-rhizomes. The experimental design was randomized block with three types of seed-rhizomes (cormel, cormel 1 and cormel 2) and seven replicates. The experimental plot consisted of 16 plants, whereas evaluated the eight central plants. It was evaluated the following characteristics: total fresh weight, net production and commercial production. It was verified that the total, net, cormel and of the cormel 1 production was greater when using the cormel rhizome as seed. However, the commercial production of the cormel was equal to the cormel 1. We recommend growing Xanthosoma mafaffa Schott using as seed cormel propagules by a larger production and for not being marketable.