Holocene vegetation and climate change recorded in alpine bog sediments from the Borreguiles de la Virgen, Sierra Nevada, southern Spain

2012 ◽  
Vol 77 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Gonzalo Jiménez-Moreno ◽  
R. Scott Anderson

High-resolution pollen and magnetic susceptibility (MS) analyses have been carried out on a sediment core taken from a high-elevation alpine bog area located in Sierra Nevada, southern Spain. The earliest part of the record, from 8200 to about 7000 cal yr BP, is characterized by the highest abundance of arboreal pollen andPediastrum, indicating the warmest and wettest conditions in the area at that time. The pollen record shows a progressive aridification since 7000 cal yr BP that occurred in two steps, first shown by a decrease inPinus, replaced by Poaceae from 7000 to 4600 cal yr BP and then by Cyperaceae,Artemisiaand Amaranthaceae from 4600 to 1200 cal yr BP.Pediastrumalso decreased progressively and totally disappeared at ca. 3000 yr ago. The progressive aridification is punctuated by periodically enhanced drought at ca. 6500, 5200 and 4000 cal yr BP that coincide in timing and duration with well-known dry events in the Mediterranean and other areas. Since 1200 cal yr BP, several changes are observed in the vegetation that probably indicate the high-impact of humans in the Sierra Nevada, with pasturing leading to nutrient enrichment and eutrophication of the bog,Pinusreforestation andOleacultivation at lower elevations.

2020 ◽  
Vol 242 ◽  
pp. 106468
Author(s):  
Gonzalo Jiménez-Moreno ◽  
R. Scott Anderson ◽  
María J. Ramos-Román ◽  
Jon Camuera ◽  
Jose Manuel Mesa-Fernández ◽  
...  

2012 ◽  
Vol 48 (3) ◽  
pp. 471-484 ◽  
Author(s):  
Antonio García-Alix ◽  
Gonzalo Jiménez-Moreno ◽  
R. Scott Anderson ◽  
Francisco J. Jiménez Espejo ◽  
Antonio Delgado Huertas

The Holocene ◽  
2011 ◽  
Vol 22 (7) ◽  
pp. 739-748 ◽  
Author(s):  
Scott Mensing ◽  
John Korfmacher ◽  
Thomas Minckley ◽  
Robert Musselman

Future climate projections predict warming at high elevations that will impact treeline species, but complex topographic relief in mountains complicates ecologic response, and we have a limited number of long-term studies examining vegetation change related to climate. In this study, pollen and conifer stomata were analyzed from a 2.3 m sediment core extending to 15,330 cal. yr BP recovered from a treeline lake in the Rocky Mountains of Wyoming. Both pollen and stomata record a sequence of vegetation and climate change similar in most respects to other regional studies, with sagebrush steppe and lowered treeline during the Late Pleistocene, rapid upward movement of treeline beginning about 11,500 cal. yr BP, treeline above modern between ~9000 and 6000 cal. yr BP, and then moving downslope ~5000 cal. yr BP, reaching modern limits by ~3000 cal. yr BP. Between 6000 and 5000 cal. yr BP sediments become increasingly organic and sedimentation rates increase. We interpret this as evidence for lower lake levels during an extended dry period with warmer summer temperatures and treeline advance. The complex topography of the Rocky Mountains makes it challenging to identify regional patterns associated with short term climatic variability, but our results contribute to gaining a better understanding of past ecologic responses at high elevation sites.


2014 ◽  
Vol 82 (3) ◽  
pp. 618-634 ◽  
Author(s):  
Ian M. Miller ◽  
Jeffrey S. Pigati ◽  
R. Scott Anderson ◽  
Kirk R. Johnson ◽  
Shannon A. Mahan ◽  
...  

AbstractIn North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5.


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