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A boreal invasion in response to climate change? Range shifts and community effects in the borderland between forest and tundra.

Elmhagen B, Kindberg J, Hellström P, Angerbjörn A - Ambio (2015)

Bottom Line: However, in addition to climate warming, suggested drivers of change include land use and other anthropogenic factors.We hypothesize all these drivers interacted, primarily favoring southern generalists.Future research should aim to distinguish between effects of climate and land-use change in boreal and tundra ecosystems.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, Stockholm University, 106 91, Stockholm, Sweden, bodil.elmhagen@zoologi.su.se.

ABSTRACT
It has been hypothesized that climate warming will allow southern species to advance north and invade northern ecosystems. We review the changes in the Swedish mammal and bird community in boreal forest and alpine tundra since the nineteenth century, as well as suggested drivers of change. Observed changes include (1) range expansion and increased abundance in southern birds, ungulates, and carnivores; (2) range contraction and decline in northern birds and carnivores; and (3) abundance decline or periodically disrupted dynamics in cyclic populations of small and medium-sized mammals and birds. The first warm spell, 1930-1960, stands out as a period of substantial faunal change. However, in addition to climate warming, suggested drivers of change include land use and other anthropogenic factors. We hypothesize all these drivers interacted, primarily favoring southern generalists. Future research should aim to distinguish between effects of climate and land-use change in boreal and tundra ecosystems.

No MeSH data available.


Related in: MedlinePlus

Density of breeding pairs of common kestrel and rough-legged buzzard in Stora Sjöfallet National Park 1970–1978 and 2001–2011. Density estimates include breeders only, i.e., nests where egg clutches were initiated. Both species are rodent specialists at this site, and short-term variation in breeding density is largely explained by numerical responses to small mammal fluctuations. Thus, the density of breeding pairs during rodent peaks is the most reliable population estimate. The rough-legged buzzard declined in Sweden in 1980–2000 (Kjellén and Roos 2000). In Stora Sjöfallet National Park, the average rough-legged buzzard breeding density in rodent peak years was lower in 2001–2011 compared to that in 1970–1978 (this figure)
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Fig5: Density of breeding pairs of common kestrel and rough-legged buzzard in Stora Sjöfallet National Park 1970–1978 and 2001–2011. Density estimates include breeders only, i.e., nests where egg clutches were initiated. Both species are rodent specialists at this site, and short-term variation in breeding density is largely explained by numerical responses to small mammal fluctuations. Thus, the density of breeding pairs during rodent peaks is the most reliable population estimate. The rough-legged buzzard declined in Sweden in 1980–2000 (Kjellén and Roos 2000). In Stora Sjöfallet National Park, the average rough-legged buzzard breeding density in rodent peak years was lower in 2001–2011 compared to that in 1970–1978 (this figure)

Mentions: A large number of birds of prey, as well as the omnivorous gulls, are predators on small rodents (Krebs 2011). The common gull (Larus canus) and black-headed gull (Chroicocephalus ridibundus) expanded in inland northern Sweden in 1930–1950. The common gull also established in the alpine tundra in the 1960s (Svensson et al. 1999). The Eurasian kestrel (Falco tinnunculus) was a rare breeder in at least some mountain regions during the 1970s, but is now at least locally abundant in birch forest and alpine tundra (Fig. 5). In boreal and alpine Sweden, rodent specialists such as northern harrier (Circus cyaneus) and rough-legged buzzard (Buteo lagopus) declined in 1940–1960 and 1980–2000 (Kjellén and Roos 2000). Likewise, boreal owl (Aegolius funereus), short-eared owl (Asio flammeus), and long-eared owl (A. otus) declined in 1980–2000 (Svensson et al. 1999; Hörnfeldt et al. 2005). The snowy owl (Bubo scandiaca) breeds only in alpine tundra. It was probably more common in the southern alpine tundra in the nineteenth century and did not breed at all in Sweden in 1982–2001 (Svensson et al. 1999; Ottvall et al. 2009). The only northern mammalian predator, the arctic fox, was abundant in the alpine tundra until the population plummeted in the early 1900s. Excessive hunting was suggested to cause the decline (Lönnberg 1927), but the arctic fox did not recover despite protection in 1928. The population declined further in 1982–2001 (Angerbjörn et al. 1995, 2013).Fig. 5


A boreal invasion in response to climate change? Range shifts and community effects in the borderland between forest and tundra.

Elmhagen B, Kindberg J, Hellström P, Angerbjörn A - Ambio (2015)

Density of breeding pairs of common kestrel and rough-legged buzzard in Stora Sjöfallet National Park 1970–1978 and 2001–2011. Density estimates include breeders only, i.e., nests where egg clutches were initiated. Both species are rodent specialists at this site, and short-term variation in breeding density is largely explained by numerical responses to small mammal fluctuations. Thus, the density of breeding pairs during rodent peaks is the most reliable population estimate. The rough-legged buzzard declined in Sweden in 1980–2000 (Kjellén and Roos 2000). In Stora Sjöfallet National Park, the average rough-legged buzzard breeding density in rodent peak years was lower in 2001–2011 compared to that in 1970–1978 (this figure)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4289007&req=5

Fig5: Density of breeding pairs of common kestrel and rough-legged buzzard in Stora Sjöfallet National Park 1970–1978 and 2001–2011. Density estimates include breeders only, i.e., nests where egg clutches were initiated. Both species are rodent specialists at this site, and short-term variation in breeding density is largely explained by numerical responses to small mammal fluctuations. Thus, the density of breeding pairs during rodent peaks is the most reliable population estimate. The rough-legged buzzard declined in Sweden in 1980–2000 (Kjellén and Roos 2000). In Stora Sjöfallet National Park, the average rough-legged buzzard breeding density in rodent peak years was lower in 2001–2011 compared to that in 1970–1978 (this figure)
Mentions: A large number of birds of prey, as well as the omnivorous gulls, are predators on small rodents (Krebs 2011). The common gull (Larus canus) and black-headed gull (Chroicocephalus ridibundus) expanded in inland northern Sweden in 1930–1950. The common gull also established in the alpine tundra in the 1960s (Svensson et al. 1999). The Eurasian kestrel (Falco tinnunculus) was a rare breeder in at least some mountain regions during the 1970s, but is now at least locally abundant in birch forest and alpine tundra (Fig. 5). In boreal and alpine Sweden, rodent specialists such as northern harrier (Circus cyaneus) and rough-legged buzzard (Buteo lagopus) declined in 1940–1960 and 1980–2000 (Kjellén and Roos 2000). Likewise, boreal owl (Aegolius funereus), short-eared owl (Asio flammeus), and long-eared owl (A. otus) declined in 1980–2000 (Svensson et al. 1999; Hörnfeldt et al. 2005). The snowy owl (Bubo scandiaca) breeds only in alpine tundra. It was probably more common in the southern alpine tundra in the nineteenth century and did not breed at all in Sweden in 1982–2001 (Svensson et al. 1999; Ottvall et al. 2009). The only northern mammalian predator, the arctic fox, was abundant in the alpine tundra until the population plummeted in the early 1900s. Excessive hunting was suggested to cause the decline (Lönnberg 1927), but the arctic fox did not recover despite protection in 1928. The population declined further in 1982–2001 (Angerbjörn et al. 1995, 2013).Fig. 5

Bottom Line: However, in addition to climate warming, suggested drivers of change include land use and other anthropogenic factors.We hypothesize all these drivers interacted, primarily favoring southern generalists.Future research should aim to distinguish between effects of climate and land-use change in boreal and tundra ecosystems.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, Stockholm University, 106 91, Stockholm, Sweden, bodil.elmhagen@zoologi.su.se.

ABSTRACT
It has been hypothesized that climate warming will allow southern species to advance north and invade northern ecosystems. We review the changes in the Swedish mammal and bird community in boreal forest and alpine tundra since the nineteenth century, as well as suggested drivers of change. Observed changes include (1) range expansion and increased abundance in southern birds, ungulates, and carnivores; (2) range contraction and decline in northern birds and carnivores; and (3) abundance decline or periodically disrupted dynamics in cyclic populations of small and medium-sized mammals and birds. The first warm spell, 1930-1960, stands out as a period of substantial faunal change. However, in addition to climate warming, suggested drivers of change include land use and other anthropogenic factors. We hypothesize all these drivers interacted, primarily favoring southern generalists. Future research should aim to distinguish between effects of climate and land-use change in boreal and tundra ecosystems.

No MeSH data available.


Related in: MedlinePlus