Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2021
Erindi/veggspjald / Talk/poster V14
Höfundar / Authors: (1) Erpur Snær Hansen
Starfsvettvangur / Affiliations: Náttúrustofa Suðurlands
Kynnir / Presenter: Erpur Snær Hansen
Population growth rate (lambda) of Atlantic puffins (Fratercula artica) breeding in Iceland is illustrated for the four neritic zones and the whole country between 2010-2021 (since 2007 for the Westman Islands). The growth rate is calculated by running a Leslie Matrix script in R with Icelandic information on sexual maturity and survival, but most importantly direct measures of chick production from 12 colonies around Iceland within the Icelandic Puffin Population Monitoring Programme (the „Puffin Rally“). Population growth has been high and steady in the North region (λ>1). The same applies for the East region, save the breeding failure years of 2010 -11. West region started low but has been λ>1 since 2015. Westman Islands (South region) has about 40% of the Icelandic population and have experienced λ<1 until 2019. Westmans have reduced the national mean below λ=1 until 2021. Geometric mean λ = 0.967 between 2010-2020, or -2.5% reduction per year. Calculated population reduction 2003-2020 is -45%. Harvest is unsustainable when λ<1, and is additive to the rate of decline. Harvest has reduced 90% between 1995-2019, without a change in hunting effort. Population growth rate has been rising the whole period and is possibly entering a surplus production phase if this trend continues.