Wetland Restoration with Hydrophytes: A Review

Abstract

Restoration cases with hydrophytes (those which develop all their vital functions inside the water or very close to the water surface, e.g., flowering) are less abundant compared to those using emergent plants. Here, I synthesize the latest knowledge in wetland restoration based on revegetation with hydrophytes and stress common challenges and potential solutions. The review mainly focusses on natural wetlands but also includes information about naturalized constructed wetlands, which nowadays are being used not only to improve water quality but also to increase biodiversity. Available publications, peer-reviewed and any public domain, from the last 20 years, were reviewed. Several countries developed pilot case-studies and field-scale projects with more or less success, the large-scale ones being less frequent. Using floating species is less generalized than submerged species. Sediment transfer is more adequate for temporary wetlands. Hydrophyte revegetation as a restoration tool could be improved by selecting suitable wetlands, increasing focus on species biology and ecology, choosing the suitable propagation and revegetation techniques (seeding, planting). The clear negative factors which prevent the revegetation success (herbivory, microalgae, filamentous green algae, water and sediment composition) have to be considered. Policy-making and wetland restoration practices must more effectively integrate the information already known, particularly under future climatic scenarios.

Long-Term Changes in Floristic Diversity as an Effect of Transforming the Lake into a Retention Reservoir

“…The diversity of species richness in such reservoirs has been widely described in the literature. The examples of Scandinavian reservoirs confirm that large fluctuations significantly impoverish the diversity of aquatic vegetation [41,42]. Other studies indicate that fluctuations with low dynamics and frequency increase diversity [43].…”

Re-Establishment Techniques and Transplantations of Charophytes to Support Threatened Species

“…Two regional reviews summarized global experiences and case studies concerning transplantations of submerged macrophytes (van de Weyer et al, 2021 [ 83 ]) and submerged macrophytes with focus on charophytes (Blindow 2019 [ 71 ]). Finally, Rodrigo (2021 [ 84 ]) reviewed revegetation with submerged macrophytes including charophytes as a restoration tool for natural and constructed wetlands.…”

“…Other transplantation projects prefer charophytes, as they are bottom-dwellers and therefore are less disturbing for various activities such as boating and swimming than tall macrophytes (Hilt et al, 2006 [ 80 ]); they also provide valuable habitats for fish (Dick et al, 2004 [ 113 ], Dick and Smart 2004 [ 114 ]). A mixture of aquatic macrophytes including charophytes is sometimes transplanted to increase biodiversity (Rodrigo and Carabal 2020 [ 108 ], Rodrigo 2021 [ 84 ]; see Figure 5 ). Charophytes were also transplanted as agents to accumulate radioactive substances (“biological polishing”; Smith and Kalin 1992 [ 97 ]).…”

“…Nitellopsis obtusa was transferred from the field to aquaria with tape water or site water in room temperature and under lamps and thus kept alive until the start of the experiments (Kurtyka et al, 2011 [ 171 ], Kisnieriene et al, 2012 [ 172 ]). In a laboratory of the University of Valencia, Spain, a number of charophyte species are kept in culture in small pots containing a sand/sediment substrate mixture, which are placed in larger beakers with tape water (Rodrigo et al, 2017 [ 170 ], Rodrigo 2021 [ 84 ]).…”

The charophytes (Characeae, Charophyceae) from the Yenisey Siberia (Russia)

“…Перечень может быть расширен по результатам обследования водоемов, для которых есть относительно давние данные по редким видам харовых водорослей, предлагаемых к охране. В будущем эти водоемы могут послужить донорами растений для восстановления водных экосистем (Rodrigo, 2021) 3 (1934), 1 (1966, 2005, 2006-2009, 2014)…”