Rapid response of alpine timberline vegetation to the Younger Dryas climate oscillation in the Colorado Rocky Mountains, USA

Reasoner, Mel A.; Jodry, Margret A.

doi:10.1130/0091-7613(2000)028<0051:rroatv>2.3.co;2

Cited by 41 publications

(63 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, a lack of high‐resolution western climate records may have prevented a sufficiently close evaluation of resilience and disequilibrium dynamics across western forests during past millennia. While unexpected, given the apparent complacency of Rocky Mountain forests, the responsiveness of the vegetation at Summit Lake to climate change has analogs in the rapid changes of modern ecotones (Allen and Breshears , Elliott ) and in the subalpine and boreal vegetation responses to past abrupt climate changes at the end of the Pleistocene in the Rocky Mountains (Reasoner and Box , Briles et al. , Krause and Whitlock ) and elsewhere (Birks and Ammann , Williams et al.…”

Section: Discussionmentioning

confidence: 99%

Extensive wildfires, climate change, and an abrupt state change in subalpine ribbon forests, Colorado

Calder

Shuman

2017

Ecology

View full text Add to dashboard Cite

Ecosystems may shift abruptly when the effects of climate change and disturbance interact, and landscapes with regularly patterned vegetation may be especially vulnerable to abrupt shifts. Here we use a fossil pollen record from a regularly patterned ribbon forest (alternating bands of forests and meadows) in Colorado to examine whether past changes in wildfire and climate produced abrupt vegetation shifts. Comparing the percentages of conifer pollen with sedimentary δ O data (interpreted as an indicator of temperature or snow accumulation) indicates a first-order linear relationship between vegetation composition and climate change with no detectable lags over the past 2,500 yr (r = 0.55, P < 0.001). Additionally, however, we find that the vegetation changed abruptly within a century of extensive wildfires, which were recognized in a previous study to have burned approximately 80% of the surrounding 1,000 km landscape 1,000 yr ago when temperatures rose ~0.5°C. The vegetation change was larger than expected from the effects of climate change alone. Pollen assemblages changed from a composition associated with closed subalpine forests to one similar to modern ribbon forests. Fossil pollen assemblages then remained like those from modern ribbon forests for the following ~1,000 yr, providing a clear example of how extensive disturbances can trigger persistent new vegetation states and alter how vegetation responds to climate.

show abstract

Section: Discussionmentioning

confidence: 99%

Extensive wildfires, climate change, and an abrupt state change in subalpine ribbon forests, Colorado

Calder

Shuman

2017

Ecology

View full text Add to dashboard Cite

show abstract

“…Other areas and systems also demonstrate tight ecological coupling with climatic changes during the YD. For example, alpine timberline vegetation in the Rocky Mountains of North America moved downslope during the early parts of the YD, followed by movement upslope at the end of the YD, consistent with climatic control of tree line (Reasoner & Jodry 2000). In this system, the major shifts between different vegetational communities are almost exactly concordant with the onset and termination of the YD.…”

Section: Extrinsic Regime Shifts: Ecological and Evolutionary Responsmentioning

confidence: 92%

Extrinsic and intrinsic forcing of abrupt ecological change: case studies from the late Quaternary

2011

View full text Add to dashboard Cite

Summary1. Abrupt changes and regime shifts are common phenomena in terrestrial ecological records spanning centuries to millennia, thus offering a rich opportunity to study the patterns and drivers of abrupt ecological change. 2. Because Quaternary climate changes also often were abrupt, a critical research question is to distinguish between extrinsic versus intrinsic abrupt ecological changes, i.e. those externally driven by abruptly changing climates, versus those resulting from thresholds, tipping points, and other nonlinear responses of ecological systems to progressive climate change. Extrinsic and intrinsic abrupt ecological changes can be distinguished in part by compiling and analysing regional networks of palaeoecological records. 3. Abrupt ecological changes driven by spatially coherent and abrupt climate changes should manifest as approximately synchronous ecological responses, both among different taxa at a site and among sites. However, the magnitude and direction of response may vary among sites and taxa. Ecological responses to the rapid climatic changes accompanying the last deglaciation offer good model systems for studying extrinsic abrupt change. 4. When abrupt ecological changes are intrinsically driven, the timing and rate of ecological response to climate change will be strongly governed by local biotic and abiotic processes and by stochastic processes such as disturbance events or localized climatic extremes. Consequently, at a regional scale, one should observe 'temporal mosaics' of abrupt ecological change, in which the timing and rate of ecological change will vary among species within sites and among sites. These temporal mosaics are analogous to the spatial mosaics observed in ecological systems prone to threshold switches between alternate stable states. The early Holocene aridification of the North American mid-continent and the middle-Holocene aridification of North Africa may be good examples of temporal mosaics. 5. Synthesis. Past instances of extrinsic and intrinsic abrupt change are of direct relevance to global-change ecologists. The former allow study of the capacity of ecological systems to quickly adjust to abrupt climate changes, while the latter offer opportunities to understand the ecological processes causing abrupt local responses to regional climate change, to test tools for predicting critical thresholds, and to develop climate-adaptation strategies.

show abstract

“…Pollen ratios have been used extensively to infer altitudinal movements of treeline in the Rocky Mountains (Maher 1963; Andrews et al . 1975; Kearney & Luckman 1983; Short 1985; Beaudoin 1986; Reasoner & Jodry 2000) and in Europe (Jalut et al . 1996; David 1997).…”

Section: Methodsmentioning

confidence: 99%

Pinus sylvestris treeline development and movement on the Kola Peninsula of Russia: pollen and stomate evidence

et al. 2002

View full text Add to dashboard Cite

Summary A sediment core recovered from Poteryanny Zub Lake on the Kola Peninsula of Russia (68°48′91″ N, 35°19′32″ E) provides fossil pollen and stomate evidence for Pinus sylvestris treeline development and movement. The site today lies in birch forest tundra, approximately 25 km north of the pine treeline and 90 km south of the Murman Coast. The record begins approximately 10 050 14C years before present (bp). The post‐glacial tundra, typified by various herbaceous taxa and Artemisia, was followed by Betula‐dominated woodland forest with Polypodiaceae‐Gramineae pollen types. Such vegetation assemblages are not analogous to any in the western Kola Peninsula today. Stomate evidence demonstrates that Pinus sylvestris immigrated to the study site as early as 8150 14C bp. Pine forest probably expanded northwards from sparse or small disjunct populations, which established c. 1000 14C bp before the expansion evident in the pollen and wood macrofossil records (7200 14C bp). Betula and other shrub and herb taxa declined at this time, possibly as a result of shading by the pine canopy. The presence of fossil Pinus sylvestris stomates and wood, together with AP : NAP ratios, indicates that the pine treeline was some 100 km north of its present position by the end of the middle Holocene warming (7000–6000 14C bp). This places it near the Barents Sea coast, currently tundra vegetation. An approximate 2 °C increase in regional summer temperatures would be necessary to move the treeline to the present‐day coastline. From 6000 14C bp the pine treeline gradually retreated southward to its present modern position. Birch woodland has grown at the site since c. 3000 14C bp.

show abstract

Rapid response of alpine timberline vegetation to the Younger Dryas climate oscillation in the Colorado Rocky Mountains, USA

Cited by 41 publications

References 0 publications

Extensive wildfires, climate change, and an abrupt state change in subalpine ribbon forests, Colorado

Extensive wildfires, climate change, and an abrupt state change in subalpine ribbon forests, Colorado

Extrinsic and intrinsic forcing of abrupt ecological change: case studies from the late Quaternary

Pinus sylvestris treeline development and movement on the Kola Peninsula of Russia: pollen and stomate evidence

Contact Info

Product

Resources

About