The Importance of Propagule Dispersal in Maintaining Local Populations of Rare Algae on Complex Coastlines: Padina pavonica on the South Coast of England

Roger J.H Herbert,John Baugh,Jay Willis

doi:10.3390/phycology1010001

Roger J.H Herbert, John Baugh + Show 1 more

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https://doi.org/10.3390/phycology1010001

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Abstract

On dynamic coastlines, populations of protected algal species with poor dispersal might be especially vulnerable to infrequent recruitment events and local extinction. As a model, we here consider the dispersal of the alga Padina pavonica from the largest remaining and physically isolated enclaves on the south coast of England. A bio-physical model was used to investigate the likely importance of local propagule dispersal in maintaining populations. Dispersal kernels that simulate the position of propagules at different time steps over 5 days were examined from five release sites. Exceptionally steep declines in model propagule density were observed over the first few hours from release, yet over the first day, 75–85% of model propagules remained close to their source but had not reached other enclaves. After five days, the dispersal from source populations ranged from 0 to 50 km, with only ~5% remaining within the source 1 km2 area. Although distances of modelled propagule dispersal might be adequate for maintaining a regional population network, vegetative perrenation also appears to be important for persistence of P. pavonica. For rare and protected species on isolated and energetic coastlines, local conservation efforts, rather than a reliance on a wider meta-population network, remain very important to ensure long-term protection and survival.

Highlights

Published: 28 June 2021Inshore coastal ecosystems are under pressure due to rising sea temperatures, sea level rise and the risk of habitat loss due to a wide variety of anthropogenic disturbances [1,2,3].There is a need to more accurately understand the dispersal and recruitment of marine organisms in an era of unprecedented change
To identify the location of habitat barriers that might limit the recovery of degraded habitats or the expansion of a marine organisms range due to climatic changes, there is need for a much greater understanding of propagule dispersal, connectivity and species persistence especially along complex coastlines [12]
The Isle of Wight on the south coast of England (Figure 1) has five of the largest enclaves of Padina pavonica remaining in the British Isles and these are located at sites with varied wave exposure and substratum [37,47]

Summary

Introduction

There is a need to more accurately understand the dispersal and recruitment of marine organisms in an era of unprecedented change. Convoluted coastlines, with their proximate variation in the degree of wave exposure and habitat, will often be of high conservation value and there is a need to understand how populations of protected species, especially those with relatively poor means of dispersal, can persist in these areas where tidal currents can be locally very strong. To identify the location of habitat barriers that might limit the recovery of degraded habitats or the expansion of a marine organisms range due to climatic changes, there is need for a much greater understanding of propagule dispersal, connectivity and species persistence especially along complex coastlines [12]. In the development of conceptual frameworks of Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations

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