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Background: Islands are particularly sensitive to biological invasions. The arrival of humans with their cohort of accompanying species has been cited as one of the primary causes for ecosystem change. Question: The introduction of these non-native species has been largely responsible for the tragic disappearance of native island biota and the dismantling of island ecosystems worldwide. Methods: Ordination analyses to determined changes in native and exotic species composition along the period analysed. Results: Mean temperature on the island of Tenerife has increased by around 0.6 °C in the last 70 years,°C in the last 70 years, C in the last 70 years, while minimum temperature has risen by approx. 1.5 °C. Despite overall warming being milder than in°C.Despite overall warming being milder than in C. Despite overall warming being milder than in the northern hemisphere, owing to the more sensitive biota these changes may have a strong influence on biodiversity. In addition, socioeconomic indicators have also changed significantly over the last 70 years with consequences for nature conservation. In this study, we analyse which parameters are best placed to explain the increase of introduced species, not just in terms of species richness, but also in species composition. We restrict the study to thermophile invasive and introduced species, as they respond more rapidly to climate change. Conclusions: We found that socioeconomic aspects of development are important elements that relate closely to the increase in richness and changes in species composition for native as well for introduced species. In the case of invasive species richness, the average minimum temperature is the most closely related variable. However, mean temperature anomalies did not reveal any relationship with these changes. Key words: Canary Islands, CCA, DCA, correlation, global warming, introduced species Aspectos socioeconómicos y anomalías de temperatura: responsables del incremento del número de especies introducidas en las Islas Canarias (1940-2010) ResumenAntecedentes: Las islas son particularmente sensibles a las invasiones. La llegada de humanos con sus especies acompañantes son una de las primeras causas de cambios ecosistémicos. Pregunta: ¿Se relacionan las especies introducidas con la desaparición de especies a lo largo de los ecosistemas insulares del planeta? Métodos: Análisis de ordenación para determinar cambios de riqueza de especies nativas e introducidas a lo largo del periodo. Resultados: La temperatura media de la isla de Tenerife se ha incrementado en 0.6 °C en los últimos 70 años, mientras que la media de las temperaturas mínimas en aproximadamente 1.5 °C. A pesar de que el calentamiento es inferior al sufrido en el hemisferio norte, la mayor sensibilidad de la especies a estos cambios puede provocar negativos efectos en la diversidad. Por otro lado, los indicadores socieconómicos también han cambiado en los últimos 70 años con importantes cambios para el medio natural. En este trabajo analizamos que parámetros se re...

Background – Species of Agave and Furcraea (Agavaceae, Asparagaceae s. lat.) are widely cultivated as ornamentals in Mediterranean climates. An increasing number is escaping and naturalising, also in natural habitats in the Canary Islands (Spain). However, a detailed treatment of variously naturalised and invasive species found in the wild in the Canary Islands is not available and, as a result, species identification is often problematic.Methods – The present study is based on many years of fieldwork on the islands of Fuerteventura, Gran Canaria, Lanzarote and Tenerife. Results – Fourteen species and several additional infraspecific taxa of Agave have been identified. In addition to the widely naturalised and invasive Agave americana, A. fourcroydes and A. sisalana (incl. the not previously reported var. armata), the following species of Agave were observed: A. angustifolia (incl. var. marginata), A. attenuata, A. filifera, A. franzosinii, A. lechuguilla, A. macroacantha, A. murpheyi, A. oteroi, A. salmiana (var. ferox and var. salmiana), A. aff. tequilana and A. vivipara. From the genus Furcraea three species were found: F. foetida, F. hexapetala and F. selloana. Several of these newly detected species of Agave and Furcraea are at least locally naturalised. A key for the identification of the representatives of these genera in the study area is presented and all species are illustrated. Additional nomenclatural, taxonomic and ecological notes are also provided.

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