Beware of changes: Conservation of Indo‐Pacific humpback dolphins in disturbed habitats

Abstract

Protecting critical habitats of the Indo‐Pacific humpback dolphin, Sousa chinensis, is a hot topic of discussion for marine biodiversity conservation in China and many Southeast Asian countries. In practice, sound habitat protection action (HPA) planning often suffers from information gaps in macroscopic habitat configurations and changes in the habitat conditions of humpback dolphins. Recent publications in the journal Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) have served to advance humpback dolphin conservation in Chinese waters by resolving such habitat configurations and indicating significant changes in distribution patterns and habitat characteristics under intense coastal anthropogenic activity. We highlight an integrative research framework to investigate habitat configuration and long‐term habitat changes when planning a holistic HPA programme for humpback dolphins. When constructing habitat configuration baselines, field surveys should be designed and conducted in a systematic manner to ensure survey efforts cover diverse environments equally, in either a spatially stratified or gridded pattern, to minimize potential spatial sampling biases. Long‐term habitat changes can be revealed by comparing satellite images from different decades. Changes in habitat preferences and habitat characteristics can be explored through questionnaire surveys on local ecological knowledge, associating historical occurrences with coastline features and projecting historical habitat configuration by species distribution modelling exercises. A lack of good communication and sharing of information between research and management sectors can still be an obstacle to the implementation of sound conservation practices, however, even though there is robust scientific evidence to fill knowledge gaps in distribution and habitat baselines. We have addressed the need to establish a mechanism to improve and streamline information sharing between research teams, management sectors, and stakeholder groups.

Mapping habitat protection priority over a marine ecoregion under information gaps

“…In the Gulf of Thailand, known occurrences of humpback dolphins and Irrawaddy dolphins were reported not only in Surat Thani–Khanom waters (Jutapruet et al., 2015, 2017), but also in the eastern and upper Gulf of Thailand (Andersen & Kinze, 2000) which were included in the likely habitats projected by MaxEnt scenarios (Figure 2). Similar consistency was also reported for Indo‐Pacific humpback dolphins in Chinese waters (Chen et al., 2020; Huang et al., 2020). MaxEnt scenarios can help to map likely habitats that are never or seldom investigated over a wide spatial range (Huang et al., 2020).…”

“…Coastal and estuarine waters are important marine ecosystems which feature high primary production, biomass and biodiversity, as well as provision of multiple ecosystem functions and services (Guen et al., 2019; Savage et al., 2012; Wu et al., 2017). The persistence of ecosystem functions in coastal and estuarine waters is degraded by growing maritime activities (Huang et al., 2018; Huang et al., 2020; Guen et al., 2019; Murray et al., 2019). The protection of coastal and estuarine ecosystems demands holistic planning that addresses the management of entire ecosystems (Barbier et al., 2008; Curtin & Prellezo, 2010; Domínguez‐Tejo et al., 2016).…”

“…The first step to solve information gaps in MCP practices is to map the biodiversity configuration as thoroughly as possible (Ardron et al., 2010; Ball et al., 2009; Game & Grantham, 2008). The major difficulty in building a holistic baseline comes from the vast spatial scale of the marine environment, particularly for an entire marine ecoregion (Spalding et al., 2007) that is not comprehensively and systematically surveyed (Huang et al., 2020). It may be necessary to use species whose habitat configurations encompass regional biodiversity patterns over a wide spatial area as MCP surrogates (Barton et al., 2020; Rodrigues & Brooks, 2007; Ward et al., 2019).…”

“…It may be necessary to use species whose habitat configurations encompass regional biodiversity patterns over a wide spatial area as MCP surrogates (Barton et al., 2020; Rodrigues & Brooks, 2007; Ward et al., 2019). The application of species distribution modelling (SDM) can help resolve gaps in the habitat configuration of those surrogates (Huang et al., 2020; Jackson‐Ricketts et al., 2020; Marshall et al., 2014). For widely occurring marine animals such as marine mammals, sharks and sea turtles, this approach is particularly valuable as the costs to collect statistically representative data for these animals are often high (Becker et al, 2019).…”

“…Both coastal delphinids (humpback dolphins and Irrawaddy dolphins) and sea turtles are reported to be significantly associated with waters of high primary production and major ecosystems in tropical waters (Becker et al., 2019; Christianen et al., 2014; Jackson‐Ricketts et al., 2020; Jutapruet et al., 2017; Wu et al., 2017). The concept of using these marine megafauna species as surrogates for ecosystem‐based MCP is proposed (Huang et al., 2020) but not yet tested statistically. The present study constructed the habitat configuration of Indo‐Pacific humpback dolphins, Irrawaddy dolphins and sea turtles in the Gulf of Thailand using SDMs and then conducted MCP using the projected habitat configurations as surrogates.…”