Artificial coastal lagoons at solar salt-working sites: A network of habitats for specialised, protected and alien biodiversity

Abstract

There are concerns that novel structures might displace protected species, facilitate the spread of non-indigenous species, or modify native habitats. It is also predicted that ocean warming and the associated effects of climate change will significantly increase biodiversity loss within coastal regions. Resilience is to a large extent influenced by the magnitude of dispersal and level of connectivity within and between populations. Therefore it is important to investigate the distribution and ecological significance of novel and artificial habitats, the presence of protected and alien species and potential vectors of propagule dispersal. The legacy of solar salt-making in tropical and warm temperate regions is regionally extensive areas of artificial hypersaline ponds, canals and ditches. Yet the broad-scale contribution of salt-working to a network of benthic biodiversity has not been fully established. Artisanal, abandoned and historic salt-working sites were investigated along the Atlantic coast of Europe between southern England (50 o N) and Andalucía, Spain (36 o N). Natural lagoons are scarce along this macrotidal coast and are vulnerable to environmental change; however it is suspected that avian propagule dispersal is important in maintaining population connectivity. During bird migration periods, benthic cores were collected for infauna from 70 waterbodies across 21 salt-working sites in 5 coastal regions. Bird ringing data were used to investigate potential avian connectivity between locations. Lagoonal specialist species, some of international conservation importance, were recorded across all regions in the storage reservoirs and evaporation ponds of continental salinas, yet few non-indigenous species were observed. Potential avian propagule transport and connectivity within and between extant salt-working sites is high and these artificial habitats are likely to contribute significantly to a network of coastal lagoon biodiversity in Europe.

Beyond Site-Specific Criteria: Conservation of Migratory Birds and Their Habitats from a Network Perspective

“…Nodes can be defined as areas that birds regularly or frequently visit (Approach N1), which can be identified from existing diversity, abundance or habitat criteria (Table 1), through count, marking, or capture data (e.g., bird banding and recovery sites), or by applying home range estimators to bird tracking data [25]. This approach assumes the sites where birds were observed, marked, or captured to be staging areas for birds, and are widely defined as nodes in a species' movement network [26][27][28]. Potential sampling biases may be taken into account, e.g., poor visualization at night reduces the observation rate for nocturnal feeding, or roosting sites that are intensively used by some species (e.g., dabbling ducks [29]).…”

Where ecologically ‘tis better to go brown than green: enhanced seagrass macrobenthic biodiversity within the canals of a brownfield coastal marina

“…This may be unusual in the context of marina estates, but man-made coastal ponds and channels elsewhere have proved valuable habitats for the conservation of lagoonal and other coastal invertebrates (Barnes 1991 ; Allen et al 1995 ), fish (Cavraro et al 2021 ), and shorebirds (Rehfisch 1994 ). Most of the British coastal lagoons of conservation interest, for example, have been formed in one way or another by man, including excavated pits and scrapes (Barnes 1989 ; and see Herbert et al 2018 ). Equivalent similar aquatic pools or channels that form small islands of high biodiversity in unlikely urbanised settings, including those of the seagrassed areas in the Thesen marina canals, could be categorised as novel ecosystems in the sense of Hobbs et al ( 2009 ) produced by land-use change, and could potentially be the subject of ‘other effective area-based conservation measures’ (OECMs) (Pinto et al 2021 ) creating, for example, soft-sediment equivalents of the ‘artificial marine micro-reserves’ of García-Gómez et al ( 2015 ), Ostalé-Valriberas et al ( 2022 ), etc.…”

The Patrimonialization of Traditional Salinas in Europe, a Successful Transformation from a Productive to a Services-Based Activity

“…The economy of scale and the technology of production (mechanized vs. hand-harvested) makes artisanal salt expensive and scarce. There is also the common understanding that solar evaporation salt making is an activity that relies on a healthy environment, a resilient and biodiverse ecosystem, and a consolidated professional know-how, rendering these sites cultural landscapes with distinct values that merit protection and dissemination [5,6]. These values have gradually been acknowledged as tangible and intangible forms of heritage over the past decades, moving away from the traditional vision of monument-based heritage assets, resulting in a greater permeability of the institutions to admit new forms and scales of heritage [7,8].…”