Origin of British and Irish mammals: disparate post-glacial colonisation and species introductions

摘要: Abstract Global climate changes during the Quaternary reveal much about broader evolutionary effects of environmental change. Detailed regional studies how lineages and novel communities ecosystems, emerge through glacial bottlenecks or from refugia. There have been significant advances in benthic imaging dating, particularly with respect to movements British (Scottish) Irish ice sheets associated sea level after Last Glacial Maximum (LGM). Ireland has isolated as an island for approximately twice long Britain no evidence any substantial, enduring land bridge between these islands ca 15 kya. Recent biogeographical show that Britain's mammal community is akin those southern parts Scandinavia, The Netherlands Belgium, but lower species richness unique needs explanation. Here, we consider physiographic, archaeological, phylogeographical i.e. molecular genetic, biological comprising ecological, behavioural morphological data, review recolonized western Europe LGM emphasis on and, particular, Ireland. We focus why close neighbours had such different fauna early Holocene, stability ecosystems subject change later introductions. general concordance archaeological genetic where data allow some insight into history LGM. Phylogeography reveals process recolonization, e.g. source colonizers anthropogenic influence, whilst timing more precisely carbon dating stratigraphy. More representative samples improved calibration ‘molecular clock’ will lead further insights regards influence successive glaciations. Species showing greatest morphological, ecological divergence comparison continental Europe, were also which arrived very Holocene either without assistance people. Cold tolerant quickly disappeared, potentially a result short period rapid warming. Other arrivals less cold succumbed colder conditions Younger Dryas shortly start (11.5 kya), area suitable habitat was insufficient sustain viable population especially larger species. Late Pleistocene mammals restricted able colonize up ca 15 kya, probably originating adjacent areas unglaciated now below level, south west (of Ireland). These few, retain diversity dates before Ireland, therefore, depleted complement Britain. Mammal species, colonising predominantly southeast east occupied only far ca 15 8 kya, excluded by Celtic Seas. Smaller particular failed colonise being ca. 8 kya similar composition lowland northwest its almost all strongest affinity populations neighbouring few retaining genotypes earlier, lineages. role people deliberate introduction distinct than reflecting latter link Europe. prime motivation moving likely be resource driven cultural; elsewhere, exploring uninhabited places introduced food materials they required survive. It possible commenced Mesolithic accelerated Neolithic established, variation traces their origins principally cases, Scandinavia Iberia. interest may forms absent populations. Further introductions, Bronze late Iron Ages, Viking Norman invasions, follow same pattern lack time Accidental introductions commensal considerable based numerous translocations along eastern Atlantic coastline. recent accidental are characterised other explicable one introduction. substantial understanding postglacial mammals, translocations, determination recently introduced, should inform policy decisions conservation. Conservation prioritise early, naturally recolonizing brought association islands. value mitigating across In contrast, disturb greatly, loss controlled. This challenge severe number proportion invasive 19th century present greater