Projected climate change and limited dispersal potential threaten the seahorse species Hippocampus hippocampus and Hippocampus guttulatus

Climate change is predicted to drive species redistribution, altering the composition of marine communities and affecting ecosystem functioning. There is increasing evidence that fish distributions follow a trend of poleward expansion, while realised niches often decrease in range size. This study aimed to assess the influence of oceanographic connectivity and intrinsic dispersal mechanisms on changes in suitable habitats of the European seahorses (Hippocampus hippocampus and Hippocampus guttulatus) from the present (2010–2020) until the end of the century (2090–2100). Habitat suitability was assessed using Ensemble Species Distribution Modelling under two Shared Socio-Economic Pathways (SSP2 and SSP5) coupled with biophysical modelling to estimate oceanographic connectivity. The results show that intrinsic dispersal mechanisms and oceanographic connectivity limit the northward range expansion, while predicted habitat loss remained constant in all dispersal scenarios, with the highest habitat loss forecasted in the Mediterranean and northern Africa. Consequently, considering restricted dispersal, H. guttulatus was projected to experience a negative range change (or habitat contraction [-45% (SSP5)] as opposed to an expansion with unlimited dispersal (standard model) [+ 6% (SSP5)]. On the other hand, for H. hippocampus, a more limited range expansion [+ 8% (SSP5)] was forecasted compared to the standard model [+ 17% (SSP5)]. In addition, the lower emission scenario (SSP2) resulted in half of the habitat losses, while maintaining climate refugia for H. guttulatus populations in the north Mediterranean, Iberian Atlantic Coast, and Black Sea. This study highlights the importance of considering dispersal abilities when assessing climate change impacts on marine species distribution.

Descrição

Funding Information: Open access funding provided by FCT|FCCN (b-on). This work was funded by the Portuguese National Funds from FCT - Fundação para a Ciência e a Tecnologia, I.P., through the projects UID/04292/MARE-Centro de Ciências do Mar e do Ambiente, LA/P/0069/2020, UIDB/04326/2020 (DOI:10.54499/UIDB/04326/2020), UIDP/04326/2020 (DOI:10.54499/UIDP/04326/2020), and LA/P/0101/2020 (DOI:10.54499/LA/P/0101/2020). Furthermore, individual grants were funded by FCT for the work of FP [2020.07299.BD] and FM [Decree-Law 57/2016]. ARAL was funded by the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement [No 101038057]. The work of both FM and MP was supported by the institutional funding from the Centre for Functional Ecology - Science for People and the Planet (CFE; UIDB/04004/2020), financed by FCT through national funds (PIDDAC), and Associate Laboratory TERRA [LA/P/0092/2020]. SH was funded by the FCT Individual Call to Scientific Employment Stimulus [2023.08241.CEECIND] and by European funds of the EU HORIZON B-Useful project [HORIZON ID: 101059823]. JA was also supported by the FCT Individual Call to Scientific Employment Stimulus 2022.00861.CEECIND/CP1729/CT0003 (DOI:10.54499/2022.00861.CEECIND/CP1729/CT0003). The fieldwork in the Tagus estuary was supported by the projects CavALMar and EUROSYNG (Biodiversa+). Publisher Copyright: © The Author(s) 2025.

Palavras-chave

Climate refugia Connectivity Conservation European seahorses Habitat loss Species distribution modelling Ecology, Evolution, Behavior and Systematics Aquatic Science Ecology SDG 13 - Climate Action SDG 14 - Life Below Water