Characterization of Holocene vegetation variability in the Northern Hemisphere
Abstract
Global climatic changes expected in the 21st century are likely to create unparalleled disturbances on vegetation, but in order to establish the significance of these disturbances it is necessary to characterize and understand the typical natural vegetation variability. We investigate the variability of different vegetation biomes by examining their behaviour during the Holocene using a taxonomically harmonized and temporally standardized global fossil pollen dataset, synthesized from 2821 palynological records from the Neotoma Paleoecology Database and additional literature. Using principal component analysis, we characterize the dominant modes of vegetation composition variability in the pollen assemblages and derive timescale-dependent estimates of variability using the first-order Haar structure function. We find, on average, important centennial to millennial scale vegetation variability as well as significant coherency in the spatial patterns. We further relate the differences in variability to biome classes based on vegetation composition. As such, higher variability is identified for open land vegetation compared to forests, consistent with more active fire regimes in the former. This may also explain the higher variability of needleleaf forests on shorter (centennial) timescales, while their broadleaf counterparts showed the largest scaling of variability with timescales, indicating long-term turnover in vegetation composition.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMPP43B..10H