Halophila stipulacea is one of the invasive species of tropical seagrass that began to populate the area of the Caribbean Sea. In general, seagrass beds are vital for the sustainability of marine ecosystems. They act as key primary producers that support marine organisms and act as great nursery habitats. Other ecosystem services include storing carbon and recycling nutrients. However, globally seagrass beds are threatened and rapidly declining at nearly one hectare every hour. Multiple factors contribute to this decline, some of them are human factors, but one of the concerns is seagrass invasions. Hence, the paper investigates the invasion of Halophila Stipulacea in the Caribbean Sea and reviews the potential consequences.
Invasive species can have negative effects on ecosystems and habitats. As such, they can alter the trophic structure and disrupt environmental resources. Halophila stipulacea, as an invasive species, is displacing native seagrasses in the Caribbean (Van Tussenbroek et al., 2016). According to the early studies and the research conducted by Willette et al. (2014), in 2008, native seagrass occupied 85 per cent of the Dominica area, while invasive species occupied only 6 per cent (Winters et al., 2020). Five years later, in 2013, natives occupied only 13 per cent, with invasive species taking 86 per cent (Willette et al., 2014). Hence, the invasion rate is alarming as it changes the native ecosystem.
The studies have found the difference between the invasive strains in the Caribbean and local species. The invasive species of the Caribbean Sea have smaller, more apical shoots and larger internode distances (Willette & Ambrose, 2012). The Halophila Stipulacea is adaptive to a range of physiological conditions such as light, temperature, salinity, and nutrients (Oscar et al., 2018). These characteristics increased the rates of the invasion of the species.
Researchers are concerned with its consequences on the local ecosystem as Halophila Stipulacea is displacing native Caribbean seagrass. The displacement alters the abundance and composition of seagrass-associated organisms and the local seagrass community (Olinger et al., 2017). Yet, predicting the long-term effects of the invasion requires more research.
References
Olinger, L. K., Heidmann, S. L., Durdall, A. N., Howe, C., Ramseyer, T., Thomas, S. G.,… & Brandt, M. (2017). Altered juvenile fish communities associated with invasive Halophila stipulacea seagrass habitats in the US Virgin Islands. PLoS One, 12(11), e0188386.
Oscar, M. A., Barak, S., & Winters, G. (2018). The tropical invasive seagrass, Halophila stipulacea, has a superior ability to tolerate dynamic changes in salinity levels compared to its freshwater relative, Vallisneria americana. Frontiers in plant science, 9, 950.
Van Tussenbroek, B. I., Van Katwijk, M. M., Bouma, T. J., Van der Heide, T., Govers, L. L., & Leuven, R. S. E. W. (2016). Non-native seagrass Halophila stipulacea forms dense mats under eutrophic conditions in the Caribbean. Journal of Sea Research, 115, 1-5.
Willette, D. A., & Ambrose, R. F. (2012). Effects of the invasive seagrass Halophila stipulacea on the native seagrass, Syringodium filiforme, and associated fish and epibiota communities in the Eastern Caribbean. Aquatic Botany, 103, 74-82.
Willette, D. A., Chalifour, J., Debrot, A. D., Engel, M. S., Miller, J., Oxenford, H. A., & Védie, F. (2014). Continued expansion of the trans-Atlantic invasive marine angiosperm Halophila stipulacea in the Eastern Caribbean. Aquatic botany, 112, 98-102.
Winters, G., Beer, S., Willette, D. A., Viana, I. G., Chiquillo, K. L., Beca-Carretero, P., & Rilov, G. (2020). The tropical seagrass Halophila stipulacea: reviewing what we know from its native and invasive habitats, alongside identifying knowledge gaps. Frontiers in Marine Science, 7, 300.