20th Century Climate Warming and Tree-limit Rise in the Southern Scandes of Sweden

Kullman, Leif

doi:10.1639/0044-7447(2001)030[0072:ccwatl]2.0.co;2

Cited by 69 publications

(96 citation statements)

References 34 publications

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“…Rising treelines around the world (Kullman 2001) suggest that the spatial location of the ecotones delimiting spruce-fir habitat can shift measurably within decades; however, the precise amount of warming required to shift ecotones is controversial (Spear 1989), and it is highly likely that ecotonal shifts will lag at least decades behind climate changes (Kullman 2001). Lag times may be as long as 100 to 200 years (Woodward 1992).…”

Section: Resultsmentioning

confidence: 99%

Potential effects of climate change on birds of the Northeast

Rodenhouse

Matthews

McFarland³

et al. 2007

Mitig Adapt Strateg Glob Change

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We used three approaches to assess potential effects of climate change on birds of the Northeast. First, we created distribution and abundance models for common bird species using climate, elevation, and tree species variables and modeled how bird distributions might change as habitats shift. Second, we assessed potential effects on high-elevation birds, especially Bicknell's thrush (Catharus bicknelli), that may be particularly vulnerable to climate change, by using statistical associations between climate, spruce-fir forest vegetation and bird survey data. Last, we complemented these projections with an assessment of how habitat quality of a migratory songbird, the black-throated blue warbler (Dendroica caerulescens) might be affected by climate change. Large changes in bird communities of the Northeast are likely to result from climate change, and these changes will be most dramatic under a scenario of continued high emissions. Indeed, high-elevation bird species may currently be at the threshold of critical change with as little as 1°C warming reducing suitable habitat by more than half. Species at mid elevations are likely to experience declines in habitat quality that could affect demography. Although not all species will be affected adversely, some of the Northeast's iconic species, such as common loon and black-capped chickadee, and some of its most abundant species, including several neotropical migrants, are projected to decline significantly in abundance under all climate change scenarios. No clear mitigation strategies are apparent, as shifts in species' abundances and ranges will occur across all habitat types and for species with widely differing ecologies.

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Section: Resultsmentioning

confidence: 99%

Potential effects of climate change on birds of the Northeast

Rodenhouse

Matthews

McFarland³

et al. 2007

Mitig Adapt Strateg Glob Change

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“…Second, reduced genetic variation in the northern part of the range, consistent with population bottlenecks during postglacial expansion (39), may have limited the adaptive potential of Swedish populations relative to Italian populations. Finally, recent climatic warming in Sweden, as reflected in marked shifts in tree lines to higher elevation (40), may have increased the relative fitness of some southern alleles. Climatic warming should reduce the fitness difference between the southern and northern genotype at the northern site but possibly increase the difference at the southern site.…”

Section: Discussionmentioning

confidence: 99%

Genetic mapping of adaptation reveals fitness tradeoffs in Arabidopsis thaliana

Ågren

Oakley

McKay

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

167

320

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Organisms inhabiting different environments are often locally adapted, and yet despite a considerable body of theory, the genetic basis of local adaptation is poorly understood. Unanswered questions include the number and effect sizes of adaptive loci, whether locally favored loci reduce fitness elsewhere (i.e., fitness tradeoffs), and whether a lack of genetic variation limits adaptation. To address these questions, we mapped quantitative trait loci (QTL) for total fitness in 398 recombinant inbred lines derived from a cross between locally adapted populations of the highly selfing plant Arabidopsis thaliana from Sweden and Italy and grown for 3 consecutive years at the parental sites (>40,000 plants monitored). We show that local adaptation is controlled by relatively few genomic regions of small to modest effect. A third of the 15 fitness QTL we detected showed evidence of tradeoffs, which contrasts with the minimal evidence for fitness tradeoffs found in previous studies. This difference may reflect the power of our multiyear study to distinguish conditionally neutral QTL from those that reflect fitness tradeoffs. In Sweden, but not in Italy, the local genotype underlying fitness QTL was often maladaptive, suggesting that adaptation there is constrained by a lack of adaptive genetic variation, attributable perhaps to genetic bottlenecks during postglacial colonization of Scandinavia or to recent changes in selection regime caused by climate change. Our results suggest that adaptation to markedly different environments can be achieved through changes in relatively few genomic regions, that fitness tradeoffs are common, and that lack of genetic variation can limit adaptation.O rganisms inhabiting different environments are often locally adapted, as demonstrated by experiments showing that local populations grown in their native sites outperform other populations (1-3). Despite a large body of theory, the genetic basis of local adaptation is poorly understood. Key unanswered questions include the number and effect sizes of adaptive loci, whether locally favored loci reduce fitness elsewhere (i.e., fitness tradeoffs), and whether the adaptive potential of populations is limited by insufficient genetic variation (4-11). The Fisherian view that adaptation is a function of many genes of small effect (12) has been challenged on theoretical grounds (4, 6), and recent empirical work indicates that genes with both large and small phenotypic effects contribute to differentiation in putatively adaptive traits (e.g., refs. 8 and 13). However, there are few direct estimates of the number of loci underlying fitness variation in native environments (14).Because natural environments are variable in both time and space, temporally replicated experiments are particularly important for distinguishing whether adaptive alleles are conditionally neutral [i.e., favored locally but neutral elsewhere (7, 15)] or are favored in one environment but disfavored in the other, reflecting an adaptive tradeoff (2, 7, 16). Evidence for conditi...

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“…Temperature is generally considered to be the main natural determinant of treeline position (Kö rner and Paulsen 2004), and treelines are therefore expected to react strongly to global warming (Kullman 2001;Kupfer and Cairns 1996). However, if a treeline lies below its climatic potential, for whatever reason, the forest could extend upwards even if there is no increase in temperature.…”

Section: Introductionmentioning

confidence: 99%

High solar radiation hinders tree regeneration above the alpine treeline in northern Ecuador

2006

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Many tropical alpine treelines lie below their climatic potential, because of natural or anthropogenic causes. Forest extension above the treeline depends on the ability of trees to establish in the alpine environment. This ability may be limited by different factors, such as low temperatures, excess solar radiation, competition, soil properties, dispersal ability, and fires. In this paper we address the following two questions: Do trees regenerate above the present treeline, and what are the inhibiting factors for tree establishment? To answer these questions we described the spatial pattern of recent tree establishment below and above the present treeline in northern Ecuador. Also, we experimentally transplanted seedlings into the alpine vegetation (pá ramo) and the forest, and investigated the effect of shade, neighboring plants, and substrate on their survival. The number of naturally occurring tree sprouts (seedlings, saplings and ramets) was highest just outside the forest, and decreased with distance to the forest edge. However, only two species that were radiation-tolerant made up these high numbers, while other species were rare or absent in the pá ramo. In the forest, the species diversity of sprouts was high and the abundance per species was relatively low. The transplanted seedlings survived least in experimental plots without artificial shade where neighboring plants were removed. Seedling survival was highest in artificially shaded plots and in the forest. This shade-dependence of most tree species can strongly slow down forest expansion toward the potential climatic treeline. Due to the presence of radiation-tolerant species, the complete lack of forest expansion probably needs to be ascribed to fire. However, our results show that natural processes can also explain both the low position and the abruptness of tropical treelines.

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20th Century Climate Warming and Tree-limit Rise in the Southern Scandes of Sweden

Cited by 69 publications

References 34 publications

Potential effects of climate change on birds of the Northeast

Potential effects of climate change on birds of the Northeast

Genetic mapping of adaptation reveals fitness tradeoffs in Arabidopsis thaliana

High solar radiation hinders tree regeneration above the alpine treeline in northern Ecuador

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