Marine Atlas: Maximizing Benefits for Tonga

BEYOND THE HOTSPOTS: BIOREGIONS Ideally ecosystem-based marine planning should be based on comprehensive data that represents all of Ton- ga's marine plants and animals. This data, however is rarely available for any country. To overcome this limita- tion, surrogates can be used to classify the marine environment into spatial units, or bioregions, that host simi- lar plants and animals.

TONGA

The GOODS biogeographic classification from 2009 is an example of a global bioregionalization.

(see chapter “Turning sour”) or phosphate concen- tration (see chapter “The dose makes the poi- son”). Analysing and clustering such data results in spatial units, called marine “bioregions”. These bioregions present comprehensive descriptions of the marine biodiversity of Tonga and can be used for conservation, management and planning. Such marine classification and the use of biore- gions is not a new concept, as bioregions have been produced before at various scales in other countries, regions and globally, including some that encompass Tonga. The graphic provides one example of a global bioregionalization, the Global Open Oceans and Deep Seabed (GOODS) bioge- ographic classification, undertaken by the United Nations Educational, Scientific and Cultural Organ- ization (UNESCO) in 2009.

Classifications such as GOODS are very useful on a global scale. However, Tonga’s large EEZ is divided into merely three bioregions, making the existing classifications of the marine envi- ronments, both coastal and offshore, too coarse to inform most national planning processes in Tonga. This calls for more detailed bioregions to inform marine planning. The MACBIO project has developed draft marine bioregions across the South-West Pacific for use by Pacific Island countries, including Tonga, in their national plan- ning process for MSP and MPAs. In total, 262 deepwater bioregions and 102 reef-associated bioregions were defined across the South-West Pacific, which included 33 deepwater and four reef-associated bioregions in Tongan waters (Wendt et al., 2018). In 2017, in-country experts came together to consider and help verify the location, boundaries, name and description of these draft bioregions within Tongan waters. As a result, the four reef-associated bioregions were modified to reflect the participants’ knowledge of the coral reef ecosystems and associated biodi- versity in Tongan waters. The deepwater biore- gions were also refined, based on knowledge of fish assemblages and biophysical attributes, with the original 33 draft deepwater bioregions being recombined into 21 deepwater bioregions (Wendt et al., 2018). Using these bioregions as substitutes to describe the suite of marine biodiversity in Tonga, an ecologically representative system of managed and protected areas can be built. This is done by representing an example of every bioregion within an area, as well as examples of all known habitats and ecosystems (see also chapters “Nature’s hot- spots” and “Special and Unique Marine Areas”). The bioregional approach assists planners with the fact that not all habitats and ecosystems are known and mapped.

To sustainably manage and protect Tonga’s rich marine resources, the government is committed to delivering a comprehensive, ecologically represent- ative network of managed and protected marine areas (see also chapter “Tonga’s commitment to marine conservation”). Ideally, ecosystem-based marine planning should be based on comprehensive biodiversity data that represent all of Tonga’s marine plants and animals in its entire marine environment. While a lot of data are accessible—as the maps in this atlas show—comprehensive data are not available for any country, including Tonga. To over- come this limitation, surrogates must be used to classify the marine environment into spatial units, or bioregions, that can host similar plants and animals. These surrogates include factors such as salinity (see also chapter “Go with the flow”), pH

MAXIMIZING BENEFITS FOR TONGA

HABITAT VALUES

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