Socioeconomics and temperature anomalies: drivers of introduced and native plant species composition and richness in the Canary Islands (1940-2010)

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 degrees C in the last 70 years, while minimum temperature has risen by approx. 1.5 degrees 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.