Mapping habitat protection priority over a marine ecoregion under information gaps

Abstract

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Habitat protection planning for Indo‐Pacific humpback dolphins (Sousa chinensis) in deteriorating environments: Knowledge gaps and recommendations for action

“…Figure 2b shows the projected likely core habitat throughout the range of the Indo-Pacific humpback dolphin, which is much narrower than present data describing the species' range (Jefferson et al, 2017). This projection closely matches present knowledge on habitat configuration of humpback dolphins in Chinese waters (Huang et al, 2020), the Gulf of Thailand (Wang et al, 2021) and eastern Malaysia (Minton et al, 2016;Kuit et al, 2019) and implies that there are some uninvestigated habitats in waters prone to intense CEME T A B L E 1 Habitat characteristics in the core habitats of Indo-Pacific humpback dolphins, measured by bathymetry and primary production (including chlorophyll-a concentration, chla, and net primary productivity, NPP) histories by reference to the distribution of human density (CIESIN, 2018). In the absence of robust habitat configuration baselines, this habitat configuration (Figure 2b) can be adopted as a qualitative and precautionary proxy for marine conservation planning (as in Wang et al, 2021) and to measure the percentage of habitat loss for CEME environmental impact assessment.…”

“…To cope with the complexity of CEME impacts (Table 2), an integrative framework to inform habitat protection planning (Figure 4) was recommended that summarized five major components, STEPS (Huang et al, 2020) Jefferson, 2018;Peng et al, 2020). This is to unify the detectability of animals and minimize sampling bias throughout the survey space, as the basic goal is to estimate unbiased habitat configuration and population vital statistics (Guillera-Arroita et al, 2015;Passadore et al, 2018;Peng et al, 2020;Wang et al, 2021). This recommendation is particularly important for humpback dolphins in habitats near sparsely populated landscapes (Figure 2b) to build an undisturbed or lightly disturbed baseline.…”

“…'nodal' MPA network design (Bao et al, 2019) comes from the hierarchical design that delineates areas with differential protection priorities by a variety of tools for spatial protection (Ardron, Possingham & Klein, 2010;Weaver & Johnson, 2012;Day et al, 2019). Zonation algorithms like MARXAN provide a statistically sound approach for mapping habitat protection priorities at an ecoregional or national scale (Ardron, Possingham & Klein, 2010;Wang et al, 2021). In the Gulf of Thailand, Wang et al (2021) that is suitable for humpback dolphins and whether the survival of those humpback dolphins formerly inhabiting the lost habitat could be assured in the 'compensation' areas (Elliott et al, 2007).…”

“…Zonation algorithms like MARXAN provide a statistically sound approach for mapping habitat protection priorities at an ecoregional or national scale (Ardron, Possingham & Klein, 2010;Wang et al, 2021). In the Gulf of Thailand, Wang et al (2021) that is suitable for humpback dolphins and whether the survival of those humpback dolphins formerly inhabiting the lost habitat could be assured in the 'compensation' areas (Elliott et al, 2007). To the extent that humpback dolphins require a wide range of habitats to accommodate a viable population and humpback dolphins' core habitats are often associated with regional biodiversity and ecosystem function centres Wang et al, 2021), the goal of 'creating' a new environment suitable for humpback dolphins can be difficult to achieve.…”

“…Environmental variables such as salinity, riverine runoff, suspended particles, primary production and nutrient loads influence the distribution and habitat use by humpback dolphins (Jefferson, 2000;Chen et al, 2010;Minton et al, 2016;Jutapruet et al, 2017;. Recent studies based on species distribution modelling exercises highlight the importance of bathymetry and primary production (measured by chlorophyll-a concentration) in humpback dolphin distributions (Huang, Wang & Yao, 2018;Bao et al, 2019;Huang et al, 2019;Chen et al, 2020;Wang et al, 2021), which are summarized in Table 1. Some studies have used 'distance to river mouth' to describe the distribution of humpback dolphins (Li et al, 2018;Chen et al, 2020) or other coastal delphinids that fill a similar niche to that of humpback dolphins (Jackson-Ricketts et al, 2020).…”