Abstract Detail

Pacific Biogeography

Brock, James [1], Wilmshurst, Janet [2], Whitehead, Edin [1], Perry, George [3], Burns, Bruce [1].

Fern dispersal across the Pacific.

Fern dispersal has long been described as anemochorous: that microscopic spores can travel long distances, including crossing oceans, by wind. However, only the smallest spores (<25 μm) have been sampled atmospherically at sea (<500 km from shore), and little published data provides evidence of fern spores being sampled above 100 m of elevation. Experimental work has shown that spores of ferns with short-statured sporophytes (max 80 cm) will travel a distance of 2–3 m, compared to spores of tree ferns travelling between 30–100 m in forest (although probably up to 2 km in an open landscape). Furthermore, unlike lichens, mosses and liverworts, insular and continental fern communities across the southern oceans are closely correlated to geographical adjacency and not at all to wind patterns. The idea of anemochory in ferns developed from observations on the distribution of fern species across Pacific islands in the 1960s, before GPS tracking of migratory and sea bird journeys across the Pacific made the scientific community aware of the dispersal extent of these species. Our project is examining the hypothesis that wind dispersal is limited and birds also disperse fern spores at multiple spatial scales from within forests (vertically and horizontally) to long-distance across the Pacific region. We are looking at spore persistence (temporal: extraction from soil cores), resilience (tolerance to freshwater / saltwater / extreme temperatures) and dispersal potential (establishing dispersal kernels / wind-speed for lift), as well as sampling feathers and skins of migratory birds and some sea birds. Initial sampling shows that migratory birds do carry fern spores, but work to fully comprehend the ecological implications of this are ongoing.

1 - The University of Auckland, School of Biological Sciences, Thomas North, 3a Symonds Street, Auckland, 1024, New Zealand
2 - Manaaki Whenua-Landcare Research, 54 Gerald Street, Lincoln, 7608, New Zealand
3 - The University of Auckland, School of Environment, Building 302, 23 Symonds Street, Auckland, 1024, New Zealand


Presentation Type: Colloquium Presentations
Abstract ID:896
Candidate for Awards:None

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