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Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval.

Modern pollen samples provide an invaluable research tool for helping to interpret the quaternary fossil pollen record, allowing investigation of the relationship between pollen as the proxy and the environmental parameters such as vegetation, land-use, and climate that the pollen proxy represents. The European Modern Pollen Database (EMPD) is a new initiative within the European Pollen Database (EPD) to establish a publicly accessible repository of modern (surface sample) pollen data. This new database will complement the EPD, which at present holds only fossil sedimentary pollen data. The EMPD is freely available online to the scientific community and currently has information on almost 5,000 pollen samples from throughout the Euro-Siberian and Mediterranean regions, contributed by over 40 individuals and research groups. Here we describe how the EMPD was constructed, the various tables and their fields, problems and errors, quality controls, and continuing efforts to improve the available data

Sediments from Rapid Lake document glacial and vegetation history in the Temple Lake valley of the Wind River Range, Wyoming over the past 11,000 to 12,000 yr. Radiocarbon age determinations on basal detrital organic matter from Rapid Lake (11,770 ± 710 yr B.P.) and Temple Lake (11,400 ± 630 yr B.P.) bracket the age of the Temple Lake moraine, suggesting that the moraine formed in the late Pleistocene. This terminal Pleistocene readvance may be represented at lower elevations by the expansion of forest into intermontane basins 12,000 to 10,000 yr B.P. Vegetation in the Wind River Range responded to changing environmental conditions at the end of the Pleistocene. Following deglaciation, alpine tundra in the Temple Lake valley was replaced by a Pinus albicaulis parkland by about 11,300 14C yr B.P. Picea and Abies, established by 10,600 14C yr B.P., grew with Pinus albicaulis in a mixed conifer forest at and up to 100 m above Rapid Lake for most of the Holocene. Middle Holocene summer temperatures were about 1.5°C warmer than today. By about 5400 14C yr B.P. Pinus albicaulis and Abies became less prominent at upper treeline because of decreased winter snowpack and higher maximum summer temperatures. The position of the modern treeline was established by 3000 14C yr B.P. when Picea retreated downslope in response to Neoglacial cooling.

Aim To explore the relationship between modern pollen precipitation and vegetation patterns in an arid region of the Middle East.Location Data come from the central Jordan Rift from 1700 m elevation in the highlands to 300 m below sea level in the Dead Sea basin.Methods Modern pollen samples and descriptive vegetation data were collected from twenty-one locations at 100 m elevational intervals from the highest elevations on the eastern side of the rift valley, where woodlands grow, to the lowest elevation desert on earth, characterized by drought and salt tolerant plants. Pollen percentage data from each vegetation zone are compared descriptively and numerically using cluster and Principal Components Analyses (PCA).Results Three major vegetation zones: woodland, shrub steppe, and desert scrub, are identi®ed by their dominant plant species. The widely spaced tree, Quercus calliprinos Webb, de®nes the Quercus L. woodland that grows above 1500 m elevation. The shrub steppe can be divided into two subzones found between about 1500 and 900 m elevation: Artemisia herba-alba Asso shrub steppe and Artemisia L. shrub steppe with Juniperus phoenica L. Desert scrub dominates the lower elevation landscape with Hammada salicornia (Moq.) Iljin the dominant shrub between 900 and 200 m and Haloxylon persicum Bge. found below 200 m elevation. Pollen spectra re¯ect the elevational vegetation zones. In particular, Quercus L., Juniperus L. and Tamarix L. pollen are abundant where the trees grow. Highly variable amounts of non-arboreal pollen taxa ± primarily Artemisia L. and Chenopodiaceae Vent. ± differentiate shrub steppe from desert scrub vegetation. Cluster and PCA of pollen data support the qualitative vegetation zonation. Main conclusionsThe main vegetation zones along the Jordan Rift from 1700 to ±300 m elevation can be distinguished by their modern pollen precipitation. Open vegetation types, in particular, can be recognized by their pollen spectra. High amounts of Artemisia L. pollen distinguish the moister upper elevations where Artemisia L. steppe grows. In contrast, greater amounts of Chenopodiaceae Vent. pollen characterize the drier, lower elevation deserts.

Avai'o'vuna Swamp, a small coastal wetland in Vava'u, Kingdom of Tonga, produced a 4500-year pollen and sediment record. Results are: (1) a mid-Holocene sea level highstand is confirmed for Tonga between about 4500 and 2600 14C yr B.P.; marine clay contains pollen from mangroves (Rhizophora mangle), coastal forest trees (Barringtonia asiatica and Cocos nucifera), and rainforest trees (Alphitonia, Rhus, Hedycarya and Calophyllum). (2) Microscopic charcoal first appeared at 2600 14C yr B.P., coincident with the arrival of Polynesians. (3) Cocos, Pandanus, Excoecaria, Macaranga, and Elaeocarpaceae pollen reflects the establishment of a mixed coastal-lowland rainforest in the last 2500 years. (4) The loss of Hedycarya, Elaeocarpus, Calophyllum, and Guettarda and the reduction of Terminalia and taxa in the Papilionaceae family by about 1000 years ago may be due to habitat destruction and the loss of dispersal capabilities of some species through the extinction of the two largest pigeons in Tonga.

This study focuses on the relationships between plant dispersal syndromes and plant distributions at the community scale. Species composition and cover are reported from 29 10 × 20‐m vegetation plots along five topographic cross‐sections in the riparian zone of the Hassayampa River Preserve, Arizona. We find that spatial patterns of dispersal guilds vary within the flood plain of this semiarid region river. Our main results are: (1) wind‐dispersed species are fairly evenly distributed at all elevations and distances from the river, whereas cover of animal‐dispersed species increases with elevation above, and at greater distances from, the river; (2) wind‐dispersed species are proportionally more abundant in the pioneer Populus–Salix community, whereas plants in the late‐seral Prosopis community are predominantly animal‐dispersed; (3) most of the species classified as obligate‐wetland and facultative‐wetland are wind‐dispersed, whereas facultative‐upland and obligate‐upland species are mostly animal‐dispersed; and (4) there are significantly fewer wind‐dispersed species in areas of high total vegetation cover. These results may reflect successional patterns resulting from periodic flooding. Low areas close to the river flood more frequently and with greater intensity than areas farther from the river. Many pioneer species that establish in disturbed areas are wind‐dispersed. Over successional time, pioneer species cede to more drought tolerant species that are predominantly animal‐dispersed.

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