Vegetation and climate change inferred from two marine pollen records in the west Pacific during the Holocene

The palynological analysis of two marine core, MD06-3075 (6.4762°N, 125.8322°E; 1878 m water depth, 30.76 m in length) in the southern Philippines and MD98-2178 (3.6200°N, 118.7000°E; 1984 m water depth, 35.6 m in length) in the northwest Celebes Sea, the detailed oxygen isotope records, and other marine pollen records in the west Pacific, provide the regional vegetation and climate history during the Holocene. The record shows that, during the early Holocene, ~10.0-6 kyr B.P., the pollen percentage of the tropical montane forest decline, suggestting that the tropical montane forest distribute at the high altitude just like nowdays, which indicates a warm condition. The pollen from mangrove group is abundant, presenting the well-development of the mangrove along the coast of the adjacent islands. Meanwhile, the pollen from the herb is rare, but the value of the pteridophyte is much high, indicating a wet condition. During the mid-Holocene, the pollen percentage of the tropical mid-upper montane rainforest is very high at 6-5 kyr B.P, suggesting the downslope movement of the tropical montane forest, indicating a much cold condition at the time. Besides, it is a striking decline in mangrove pollen and a slight less abundance of the fern spore, indicating the vegetation group of mangrove and fern were suppressed during the mid-Holocene. During the late Holocene, a relatively high level of the herbaceous group provides a more open environment. These changes, are relatively the same as stalagmite record in this area, but different from palaeooceanographic records. This likely indicates that tropical vegetation changes have close relationship with the global monsoon.