Dagens bild 4 november 2019

Snögässen i Kanada

Ok att äta, vackra att se på och har jagats mycket.

Skjut mer snögäss!!!!! Uppmaningen från kanadensiska myndigheter.

Kanadensiska experter på den Arktiska miljön uppmanar inuiter att skjuta mer snögäss för att populationerna har vuxit utom all kontroll. Fåglarna sägs nu förstöra sin egen miljö.

Det finns två arter av snögäss plus att den ena arten är uppdelad i två olika underarter som skiljer sig åt storleksmässigt.
 


 

https://www.theglobeandmail.com/news/national/too-many-geese-big-honking-problem-for-north-scientists/article12767802/

Större Snögås, Greater Snow Goose (Anser caerulescens atlantica)

Denna gås har ökat från några tusen individer på 1930-talet till att det finns närmare 1 miljon av den idag. Den jagas nu igen sedan 1998.

“The Greater Snow Goose population underwent a dramatic increase from a few thousand individuals in the 1930s to one million birds in 1999. The Greater Snow Goose has been designated as “overabundant” and has been subject to special conservation measures to control the numbers. In fact, harvest regulations were liberalized and a spring conservation season was established in Quebec in 1998; it was subsequently extended in 2012 to southeastern Ontario. Since the implementation of special conservation measures, the population has remained relatively stable, fluctuating annually between approximately 700 000 and 1 million birds. The harvest of Greater Snow Geese has increased since the end of the 1980s and has more than doubled since the introduction of special conservation measures in Canada and the U.S.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5316327/

Mindre snögås, Lesser Snow Goose (Anser caerulescens caerulescens)

Det finns nu tre populationer av denna gås. Två finns i Kanada på sammanlagt mellan 13 och 14 miljoner. På 1970-talet uppskattas det att det fans drygt två miljoner av denna. Minst en sexdubbling. Den tredje häckar på den ryska Wrangelön och är ca 100 000.

Jakt rekommenderas i Kanada för att kontrollera populationerna.

“Lesser Snow Geese nest in colonies ranging from a few hundred to over a million birds in coastal and inland areas of the Arctic. There are three populations of Lesser Snow Geese that nest in or migrate through Canada: the Mid-continent Population, the Western Arctic Population and the Wrangel Island Population. The Mid-continent Population of Lesser Snow Geese has increased dramatically from just below 2 million in the 1970s to more than 12 million adults in the last decade. This population was designated as overabundant in 1999 and has since then been subjected to special measures to increase harvest in an attempt to control the population size and growth. The Western Arctic Population has also increased significantly, from approximately 300,000 in the 1970’s to over 1,200,000 in 2016. In 2014, the Western Arctic Population was also designated as overabundant and special conservation measures to control the population were implemented in Alberta and the Northwest Territories. In recent years, the harvest of Lesser Snow Geese has slightly increased compared to harvest levels in the 1970s, although it appears to have stabilized in the last decade despite the implementation of special conservation measures.”

Mindre snögås är i genomsnitt knappt 1 kg lättare.

Dvärgsnögås, Ross’s Goose (Anser rossii)

På 1930-talet fans det ca 3000 kvar av denna art. Betraktades som sällsynt i början på 1900-talet. Den har ökat betydligt sedan 1960-talet. Nu finns det ca 2 miljoner av denna art.

“Ross’s Geese mainly breed in the Queen Maud Gulf Region in the central Canadian Arctic, but numbers are increasing along the western coast of Hudson Bay, and on Southampton and Baffin Island. Their wintering range has also expanded eastward from historical wintering areas in California. Considered a rare species in the early part of the last century, Ross’s Geese have shown increasing numbers since the 1960s, and are among the fastest growing populations of arctic-nesting geese in recent years.  Ross’s geese were declared overabundant in the midcontinent region of the United States in 1999 and in western Canada in 2014.  Lincoln estimates of population size averaged almost 1.9 million adults from 2012-2016. The harvest of Ross’s Geese in Canada and the U.S. increased slowly from the 1960s to the 1980s and then more rapidly through the 1990s”.

“Ross's geese – which migrate between Canada's northern coastline and as far south as California – were once hunted so extensively that their numbers were down to a few thousand in the 1930s. Environmental protections and the spread of agricultural practices that favour bird foraging have changed all that.Grazing geese strip the land bare, exposing soil and peat. Recovery is slow in the Arctic's cold climate and poor soil.Ripping out vegetation changes the flow of soil moisture. It draws salts to the surface and prevents normal plants from growing back. That, in turn, affects other birds and animals.”

Varför är det problematiskt med så många snögäss?

Svaret finns i den engelska texten ovan. De äter rent på tundramarken så att underliggande jord exponeras. Ej bra då återväxten går extra sakta i artisk miljö. Salt ansamlas i markytan pga annat flöde av vatten och fukt. När saltet samlas vid markytan får vanliga växter svårare att växa och det får negativa följder för övriga organismer.

Info hämtat från:

https://www.canada.ca/en/environment-climate-change/services/migratory-game-bird-hunting/consultation-process-regulations/report-series/population-status-2017.html

 

Dessa fåglar började bli sällsynta i början på 1900-talet så därför infördes skyddslagar 1917, både gällande jakt och äggplockning. Sedan komdet torra trettiotalet som ytterligare minskade på populationerna av fåglar som häckade i våtmarker och sjöar.

En organisation vid namn ”Ducks Unlimited” startade 1937 för att köpa in marker och skydda/omvandla dem till våtmarker. Denna organisation bildades av jägare.

Se https://www.ducks.org/

 

Ca 8 miljoner ha har skyddats för speciellt andfåglar men det gynnar även andra vadare så klart.

Allt är inte bara utrotning tack och lov!