|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|5786863||1414142||2017||12 صفحه PDF||ندارد||دانلود کنید|
â¢An expansion of non-arboreal pollen between ca. 14.6â13.3 ka at Paddyâs Lake during the Antarctic Cold Reversal.â¢Regional hydroclimatic shift at ca. 6.7 ka with âmodernâ ENSO variability recorded in the tropical Pacific.â¢Local-scale shifts in vegetation, fire, and sediment geochemistry synchronous with increases in El NiÃ±o activity.â¢Possible stationarity in the spatial influence of ENSO over the study region through the Holocene.
Tropical El NiÃ±o Southern Oscillation (ENSO) is an important influence on natural systems and cultural change across the Pacific Ocean basin. El NiÃ±o events result in negative moisture anomalies in the southwest Pacific and are implicated in droughts and catastrophic wildfires across eastern Australia. An amplification of tropical El NiÃ±o activity is reported in the east Pacific after ca. 6.7Â ka; however, proxy data for ENSO-driven environmental change in Australia suggest an initial influence only after ca. 5Â ka. Here, we reconstruct changes in vegetation, fire activity and catchment dynamics (e.g. erosion) over the last 14.6Â ka from part of the southwest Pacific in which ENSO is the main control of interannual hydroclimatic variability: Paddy's Lake, in northwest Tasmania (1065Â masl), Australia. Our multi-proxy approach includes analyses of charcoal, pollen, geochemistry and radioactive isotopes. Our results reveal a high sensitivity of the local and regional vegetation to climatic change, with an increase of non-arboreal pollen between ca. 14.6â13.3Â ka synchronous with the Antarctic Cold Reversal, and a sensitivity of the local vegetation and fire activity to ENSO variability recorded in the tropical east Pacific through the Holocene. We detect local-scale shifts in vegetation, fire and sediment geochemistry at ca. 6.3, 4.8 and 3.4Â ka, simultaneous with increases in El NiÃ±o activity in the tropical Pacific. Finally, we observe a fire-driven shift in vegetation from a pyrophobic association dominated by rainforest elements to a pyrogenic association dominated by sclerophyllous taxa following a prolonged (>1Â ka) phase of tropical ENSO-amplification and a major local fire event at ca. 3.4Â ka. Our results reveal the following key insights: (1) that ENSO has been a persistent modulator of southwest Pacific climate and fire activity through the Holocene; (2) that the climate of northwest Tasmania is sensitive to long-term shifts in tropical ENSO variability; and (3) that there has been possible stationarity in the spatial influence of ENSO over this region through the Holocene.
Journal: Quaternary Science Reviews - Volume 157, 1 February 2017, Pages 164-175