Few examples of natural forest remain near the Mediterranean coast. Therefore, it is difficult to study howcoastal forests respond to climatic change or their resilience to human impact.We developed new sedimentary record of Holocene vegetation and fire history at Lago Preola, a coastal lakein southwestern Sicily (Italy). In order to verify the existence of forest at large scale on the coast, we comparepollen from Lago Preola, a medium-sized lake (33 ha), to Gorgo Basso, a small lake (3 ha) located nearby withthe aim of separating local from extra-local vegetation dynamics through time using pollen percentages andinflux. We then compare Lago Preola pollen to the record from Biviere di Gela, a large lagoon (120 ha)situated 160 km to the east in southern Sicily, to examine differences in vegetation dynamics between thetwo coastal areas during the Holocene. Lake-level reconstructions and ostracode analyses from Lago Preolaprovide vegetation-independent evidence of climate change, and help to disentangle human and climatic impactson vegetation. Pollen data indicate Pistacia-dominated shrublands replaced open grasslands in the regionsurrounding Lago Preola by 9500 cal yr BP. This change coincided with rising lake levels and thedevelopment of an ostracode fauna typical of fresh waters. Evergreen forest dominated by Quercus ilex andOlea europaea started to expand by 7000 cal BP and consolidated at 6500 cal yr BP, when lake levels werenear their Holocene high. Similarities between pollen from Lago Preola and Gorgo Basso demonstrate thatforest was the dominant vegetation type in coastal Sicily during the middle Holocene at both regional andlocal scales, and even developed in the drier climatic setting around Biviere di Gela. Lake levels fell at LagoPreola after 7000 cal yr BP, with a strong decline accompanied by increasing salinity after 4500 cal yr BP.However, no transition in vegetation matched these inferred hydrological changes. Instead, forests persistedin the surrounding region until 2200 cal BP when human disturbance intensified. We propose that differentclimatic factors control lake levels and vegetation in coastal Mediterranean ecosystems. Whereas lake levelsare most sensitive to the abundance of winter precipitation, coastal forests depend on spring precipitationand are limited by the length of summer drought. Moisture availability remained suitable for evergreen forestsin coastal Sicily during the late Holocene, and humans, not a drier climate drove the regional forestdecline.
|Numero di pagine||13|
|Rivista||PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY|
|Stato di pubblicazione||Published - 2012|
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics
- Earth-Surface Processes