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Around the world in 500 years: Inter‐regional spread of alien species over recent centuries
Author(s) -
Seebens Hanno,
Blackburn Tim M.,
Hulme Philip E.,
Kleunen Mark,
Liebhold Andrew M.,
OrlovaBienkowskaja Marina,
Pyšek Petr,
Schindler Stefan,
Essl Franz
Publication year - 2021
Publication title -
global ecology and biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.164
H-Index - 152
eISSN - 1466-8238
pISSN - 1466-822X
DOI - 10.1111/geb.13325
Subject(s) - alien , ecology , range (aeronautics) , taxon , alien species , geography , invertebrate , introduced species , invasive species , taxonomic rank , biology , demography , population , materials science , sociology , composite material , census
Aim The number of alien species has been increasing for centuries world‐wide, but temporal changes in the dynamics of their inter‐regional spread remain unclear. Here, we analyse changes in the rate and extent of inter‐regional spread of alien species over time and how these dynamics vary among major taxonomic groups. Location Global. Time period 1500–2010. Major taxa studied Vascular plants, mammals, birds, fishes, arthropods and other invertebrates. Methods Our analysis is based on the Alien Species First Record Database, which comprises >60,000 entries describing the year when an alien species was first recorded in a region (mostly countries and large islands) where it later established as an alien species. Based on the number and distribution of first records, we calculated metrics of spread between regions, which we termed “inter‐regional spread”, and conducted statistical analyses to assess variations over time and across taxonomic groups. Results Almost all (>90%) species introduced before 1700 are found in more than one region today. Inter‐regional spread often took centuries and is ongoing for many species. The intensity of inter‐regional spread increased over time, with particularly steep increases after 1800. Rates of spread peaked for plants in the late 19th century, for birds and invertebrates in the late 20th century, and remained largely constant for mammals and fishes. Inter‐regional spread for individual species showed hump‐shaped temporal patterns, with the highest rates of spread at intermediate alien range sizes. Approximately 50% of widespread species showed signs of declines in spread rates. Main conclusions Our results show that, although rates of spread have declined for many widespread species, for entire taxonomic groups they have tended to increase continuously over time. The large numbers of alien species that are currently observed in only a single region are anticipated to be found in many other regions in the future.