6 The highlands and mountains of Iceland (defined here as areas located above 400 m a.s.l) are one of the largest remaining wilderness areas in Europe. The present study was aimed to provide the first comprehensive and up-to-date data on non-native plant species from these areas. The study was aimed to answer the following questions: (1) How many non-native vascular plant species inhabit highla...

versity through genetic drift, founder effects, and genetic bottlenecks. Such events can reduce a population’s evolutionary potential and increase the risk of extinction. In this chapter, we use plant immigrants as a model system to examine the circumstances in which genetic bottlenecks do (and do not) occur and where in the hierarchical partitioning of genetic diversity such bottlenecks take p...

Mediterranean river systems are characterised by more diverse fish assemblages and regional ecological processes compared with the rest of Europe. A data set from Mediterranean France, Iberia and Greece ( 2000 sites) was used to describe the characteristics of fish assemblages, explore their responses to anthropogenic disturbance and analyse the implications for river quality assessment. There ...

More than 500 alien species were listed from the Mediterranean Sea. Though no extinction of a native species is known, sudden decline in abundance, and even local extirpations, concurrent with proliferation of aliens, had been recorded. Examination of the profound ecological impacts of some of the most conspicuous invasive alien species underscores their role, among multiple anthropogenic stres...

Alien plant invaders significantly threaten native community diversity, although it is poorly understood whether invasion initiates a linear or non-linear loss of resident species. Where low abundances of an invader have little impact on native species diversity, then a threshold level may exist, above which native communities rapidly decline. Our aim was to assess the broadscale effects of an ...

Nesting cavities are often a limited resource that multiple species use. There is an ongoing discussion on whether invasive cavity nesting birds restrict the availability of this key limited resource. While the answer to this question has important conservation implications, little experimental work has been done to examine it. Here, we aimed to experimentally test whether alien cavity nesting ...

Biological invasions cause ecological and economic impacts across the globe. However, it is unclear whether there are strong patterns in terms of their major effects, how the vulnerability of different ecosystems varies and which ecosystem services are at greatest risk. We present a global meta-analysis of 199 articles reporting 1041 field studies that in total describe the impacts of 135 alien...

Biological invasions are a major conservation threat for biodiversity worldwide. Islands are particularly vulnerable to invasive species, especially Mediterranean islands which have suffered human pressure since ancient times. In the Balearic archipelago, reptiles represent an outstanding case with more alien than native species. Moreover, in the last decade a new wave of alien snakes landed in...

What determines invasiveness of alien organisms is among the most interesting and urgent questions in ecology. In attempts to answer this question, researchers compare invasive alien species either to native species or to non-invasive alien species, and this is done in either the introduced or native ranges. However, inferences that can be drawn from these comparisons differ considerably, and f...