Date: August 28, 2018
Source: University of Vienna
Summary:
The
effects of island remoteness from the mainland on the number of species found
on islands differs strongly for non-native compared to native species. Numbers
of native species on islands decrease with greater remoteness, while numbers of
non-native species increase. An international research team has uncovered this
surprising finding. These findings have important implications for our
understanding global biodiversity.
The
effects of island remoteness from the mainland on the number of species found
on islands differs strongly for non-native compared to native species. Numbers
of native species on islands decrease with greater remoteness, while numbers of
non-native species increase. This surprising finding has been uncovered by an
international research team led by Dietmar Moser, Bernd Lenzner and Franz Essl
from the Department of Botany and Biodiversity Research of the University of
Vienna. The study has been published in the scientific journal Proceedings
of the National Academy of Sciences. These findings have important implications
for our understanding global biodiversity.
It is
widely accepted that island floras and faunas suffer from the introduction of
non-native species, with almost every third extinction event on islands being
directly or indirectly related to non-native species. Since many native island
species are endemic -- meaning they are exclusively present on "their
own" island and found nowhere else on Earth -- the introduction of
non-native species poses an imminent threat to global biodiversity. To
understand why some islands are more strongly affected than others by
non-native species, the team analyzed the effect of a number of influencing
factors on the number of native and non-native mammals, reptiles, ants, birds
and plants on 257 subtropical and tropical islands. The results confirm the
existence of long-suspected relationships, for example between the size of an
island and the number of native and non-native species present. However,
Dietmar Moser explains: "What really surprised us was to see that the
isolation of an island -- its distance from the mainland -- had opposite
effects on native and non-native species richness. Native species declined
whereas non-native species numbers increased with isolation."
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