Predicting the cumulative effect of multiple disturbances on seagrass connectivity

Grech, Alana, Hanert, Emmanuel, McKenzie, Len, Rasheed, Michael, Thomas, Christopher, Tol, Samantha, Wang, Mingzhu, Waycott, Michelle, Wolter, Jolan, and Coles, Rob (2018) Predicting the cumulative effect of multiple disturbances on seagrass connectivity. Global Change Biology, 24 (7). pp. 3093-3104.

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View at Publisher Website: https://doi.org/10.1111/gcb.14127
 
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Abstract

The rate of exchange, or connectivity, among populations effects their ability to recover after disturbance events. However, there is limited information on the extent to which populations are connected or how multiple disturbances affect connectivity, especially in coastal and marine ecosystems. We used network analysis and the outputs of a biophysical model to measure potential functional connectivity and predict the impact of multiple disturbances on seagrasses in the central Great Barrier Reef World Heritage Area (GBRWHA), Australia. The seagrass networks were densely connected, indicating that seagrasses are resilient to the random loss of meadows. Our analysis identified discrete meadows that are important sources of seagrass propagules and that serve as stepping stones connecting various different parts of the network. Several of these meadows were close to urban areas or ports and likely to be at risk from coastal development. Deep water meadows were highly connected to coastal meadows and may function as a refuge, but only for non‐foundation species. We evaluated changes to the structure and functioning of the seagrass networks when one or more discrete meadows were removed due to multiple disturbance events. The scale of disturbance required to disconnect the seagrass networks into two or more components was on average >245 km, about half the length of the metapopulation. The densely connected seagrass meadows of the central GBRWHA are not limited by the supply of propagules; therefore, management should focus on improving environmental conditions that support natural seagrass recruitment and recovery processes. Our study provides a new framework for assessing the impact of global change on the connectivity and persistence of coastal and marine ecosystems. Without this knowledge, management actions, including coastal restoration, may prove unnecessary and be unsuccessful.

Item ID: 53324
Item Type: Article (Refereed Research - C1)
Keywords: connectivity, cumulative effects, graph theory, Great Barrier Reef, networks, seagrass
Copyright Information: © 2018 John Wiley & Sons Ltd
ISSN: 1365-2486
Research Data: http://doi.org/10.4225/28/59fbbefa1337c, http://doi.org/10.4225/28/59f7ae655a579
Date Deposited: 28 Sep 2018 02:50
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 75%
05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050104 Landscape Ecology @ 25%
SEO Codes: 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 100%
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