The role of charophytes in a Mediterranean pond created for restoration purposes
Introduction
Charophytes, a component of submerged vegetation, are of considerable interest due to the numerous beneficial roles they perform (Coops, 2002, Kufel and Kufel, 2002). Charophytes participate in the establishment and maintenance of clear-water states (Blindow et al., 2002) by reducing phytoplankton biomass through a set of known mechanisms: competition for inorganic nutrients (Mulderij et al., 2007) or light limitation (Scheffer et al., 1993, Arthaud et al., 2012), allelopathy (Körner and Nicklisch, 2002, Pflugmacher, 2002, van Donk and van de Bund, 2002, Rojo et al., 2013a) and by providing refuge for herbivorous zooplankton which feeds on phytoplankton (Carpenter et al., 1985, Burks et al., 2002, Blindow et al., 2000, Blindow et al., 2002). All this can alter both the size structure and functional roles of the plankton (Bakker et al., 2013, Rojo et al., 2013a), with the final result of achieving a clear-water phase.
However, and despite their ecological relevance, charophytes remain threatened in most parts of the world, due to the deterioration and destruction of their habitats and the introduction of invasive species (del Pozo et al., 2011, Lambert and Davy, 2011, Auderset Joye and Schwarzer, 2012, Baastrup-Spohr et al., 2013). In semi-arid areas, such as the coast of the Mediterranean, the habitat has deteriorated severely (pollution, habitat destruction; Parcerisas et al., 2012). In such semi-arid habitats, where large and deep water bodies are scarce, the wetlands with their lagoons, coastal ponds and shallow and small water bodies represent essential aquatic ecosystems for the development of macrophytes in general and charophytes in particular (Martínez-Taberner and Moyà, 1991, Alonso-Guillén, 2011). These habitats are affected by eutrophication, which considerably reduces light penetration through the over development of phytoplankton, by increased salinity due to shortage of water supply and by high herbivore pressure due to the shallowness of the water columns. The synergistic combination of these stressors, which represent threats for charophytes, are probably affecting them in a complex way, and semi-arid habitats offer an opportunity to study environments where all such stressors may occur.
Albufera de València Natural Park (AVNP), a protected area of 21,000 ha that includes the largest lagoon (3500 ha) on the Iberian peninsula, an area of 14,000 ha devoted to rice fields, several shallow water bodies in inter-dunal depressions and springs, is likewise threatened. The main lagoon, largely covered by charophytes in the past (Rodrigo et al., 2010) is currently hypertrophic and has no submerged vegetation. The springs in AVNP, formerly abundant, have deteriorated (due to desiccation and pollution, Soria, 1992). The richness of charophytes in the area has been severely reduced. The local authorities have sought to allow the charophyte diversity to recover by restoring the affected springs, but the charophyte richness has not yet recovered. Seven springs in the Natural Park were examined, but charophytes (only two species, Chara vulgaris L. and Nitella hyalina (De Candolle) C. Agardh) could be detected sporadically in only two of these springs (Alonso-Guillén, 2011). Within a Reserve Area (Tancat de la Pipa) in AVNP and under the scope of a broader restoration program (Rodrigo et al., 2013a, Rodrigo et al., 2013b), a small, shallow basin was created in 2008 and flooded with groundwater in an attempt to mimic the typical springs in the area, with the goal of increasing the area's charophyte richness. The recent creation of this body of water furnishes an opportunity to investigate (i) whether charophyte diversity has increased in the area of the Natural Park but also (ii) whether charophytes are able to colonise and grow in the newly created pond as a result of the germination of propagules in the sediment bank and (iii) the ecological role of charophytes in the trophic status of this new ecosystem. We studied the propagules in the sediment bank and followed the dynamics of charophytes for four years following the creation of the new water body, and we monitored the time course followed by selected physical, chemical and biological factors. We hypothesise that (i) the new charophyte meadows, via controlling effects on nutrients and plankton, are involved with water transparency, (ii) charophyte development modifies plankton community biomass and structure, which also positively affects the trophic status of the pond, and (iii) the combination of abiotic and biotic factors, co-varying in the stressed semi-arid shallow ecosystem, can be related to the decline in the charophyte stands. Finally, based on the analysed factors, we propose countermeasures to retain charophyte in the system.
Section snippets
Study site
The artificial pond is located within the Tancat de la Pipa Reserve Area (AVNP; 39°21′57″N, 0°20′55″W; Fig. 1A), a 40 ha area formerly devoted to rice crops (Rodrigo et al., 2013a). After the construction of the basin in 2008, it was fed by groundwater sources via a deep artesian well at the end of that year. It has a surface area of approximately 4 ha and mean and maximum depths of 0.9 m and 2.2 m, respectively. The groundwater inflow is located in the northwest part of the basin, and there is an
Results
The fructifications in the sediment bank belonged to Chara aspera C.L.Willdenow, Chara baltica A.Bruzelius, Chara braunii C.C.Gmelin, Chara globularis J.L.Thuiller, Chara hispida L., C. vulgaris L., Chara sp. (an unusual fructification morphotype; Rodrigo et al., 2010), Lamprothamnium papulosum (K.Wallroth) J.Groves, N. hyalina (De Candolle) C.Agardh, Tolypella glomerata (Desvaux) Leonhardi and T. prolifera (Ziz ex A.Braun) Leonhardi. The fructifications of T. glomerata were the most abundant
The sediment seed bank
Fructifications from eleven species of charophytes were found constituting the sedimentary seed bank of the pond, including those formed by freshwater species and also by species that are characteristic of fluctuating and high saline conditions (Soulié-Märsche, 1998). The procedures used to transform former rice fields in the current Reserve Area (e.g. the construction of the basin using machinery) caused the sediments to be disturbed. The area occupied by these rice fields was previously the
Acknowledgements
The authors express thanks for the funding of this study by TRAGSA and Confederación Hidrográfica del Júcar (J. Ferrer, T. Estrela, M. Regidor) and by the Spanish Ministry of Economy and Competitiveness (research project CGL2009-10292, including plan E). We also thank Fidel Rubio, Jara García-Chicote, Fran Cortés, Sara Calero and William Colom for their help during field and laboratory work. We also thank Matthieu Lassalle, Lucía Moreno and Lurdes Ribera (Tancat de la Pipa staff), particularly
References (61)
- et al.
Effect of macrophyte community composition and nutrient enrichment on plant biomass and algal blooms
Basic Appl. Ecol.
(2010) - et al.
Seasonal changes of mechanisms maintaining clear water in a shallow lake with abundant Chara vegetation
Aquat. Bot.
(2002) - et al.
Fish effects on benthos and plankton in a Mediterranean salt marsh
J. Exp. Mar. Biol. Ecol.
(2011) Ecology of charophytes: an introduction
Aquat. Bot.
(2002)- et al.
Charophyte germination and establishment under low irradiance
Aquat. Bot.
(2004) - et al.
Can allelopathically active submerged macrophytes stabilise clear-water states in shallow eutrophic lakes?
Basic Appl. Ecol.
(2008) - et al.
New spectrophotometric equations for determining chlorophylls a, b, c1, and c2 in higher plants, algae and natural phytoplankton
Biochem. Physiol. Pflanz.
(1975) - et al.
Chara beds acting as nutrient sinks in shallow lakes—a review
Aquat. Bot.
(2002) - et al.
Calcium carbonate incrustation and phosphorus fractions in five charophyte species
Aquat. Bot.
(2013) - et al.
Macrophyte–phytoplankton interactions: the relative importance of allelopathy versus other factors
Ecol. Modell.
(2007)
Response of herbivorous water-birds to the return of Chara in Lake Veluwemeer, The Netherlands
Aquat. Bot.
Land use changes, landscape ecology and their socioeconomic driving forces in the Spanish Mediterranean coast (El Maresme County, 1850–2005)
Environ. Sci. Policy
Chara hispida beds as a sink of nitrogen: evidence from growth, nitrogen uptake and decomposition
Aquat. Bot.
Reconstruction of the former charophyte community out of the fructifications identified in Albufera de València lagoon sediments
Aquat. Bot.
Restoration of two small Mediterranean lagoons: the dynamics of submerged macrophytes and factors that affect the success of revegetation
Ecol. Eng.
The role of eutrophication reduction of two small man-made Mediterranean lagoons in the context of a broader remediation system: effects on water quality and plankton contribution
Ecol. Eng.
Assessing the potential of Albufera de València Lagoon sediments for the restoration of charophyte meadows
Ecol. Eng.
The allelopathic capacity of submerged macrophytes shapes the microalgal assemblages from a recently restored coastal wetland
Ecol. Eng.
Allelopathic effects of microcystin-LR on the germination, growth and metabolism of five charophyte species and one submerged angiosperm
Aquat. Toxicol.
Alternative equilibria in shallow lakes
Trends Ecol. Evol.
The effects of ammonium on growth, accumulation of free amino acids and nutritional status of young phosphorus deficient Stratiotes aloides plants
Aquat. Bot.
Temporal export of nitrogen from a constructed wetland: influence of hydrology and senescing submerged plants
Ecol. Eng.
Impact of submerged macrophytes including charophytes on phyto- and zooplankton communities: allelopathy versus other mechanisms
Aquat. Bot.
Charophytes in restoration of aquatic ecosystems. A study case within Albufera de València Natural Park
Ph.D. Thesis
Factors controlling planktonic size spectral responses to autumnal circulation in a Mediterranean lake
Freshwater Biol.
Standard Methods for the Examination of Water and Wastewater
Effect of light stress from phytoplankton on the relationship between aquatic vegetation and the propagule bank in shallow lakes
Freshwater Biol.
Liste Rouge characées. Espèces menacées en Suisse. Etat-2010
Seventy years of changes in the abundance of Danish charophytes
Freshwater Biol.
Restoring macrophyte diversity in shallow temperate lakes: biotic versus abiotic constraints
Hydrobiologia
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Climate features or the composition of submerged vegetation? Which factor has a greater impact on the phytoplankton structure in temperate lakes?
2023, Ecological IndicatorsCitation Excerpt :Thanks to the biotransformation capacity of cyanobacterial toxins, macrophytes are regarded as the green liver for a body of water (Nimptsch et al., 2008). Therefore, high macrophyte abundance and diversity prevent the shift towards phytoplankton dominance and cyanobacterial blooms commonly resulting from excessive nutrient loading (Sayer et al., 2010) that helps to restore eutrophic water bodies (Rodrigo et al., 2015). Among submerged macrophytes, charophytes and angiosperms are particularly important for the phytoplankton abundance and composition in lakes, but the direct and indirect feedback mechanisms of the macrophyte-phytoplankton interplay are different (Blindow et al., 2014).
Gravel pit lakes in Denmark: Chemical and biological state
2018, Science of the Total EnvironmentCitation Excerpt :For the investigated variables, the gravel pit lakes seem to develop relatively fast into ecosystems that are similar to natural lakes. Where macrophyte propagules are present, newly created shallow lakes or ponds may be populated rapidly by charophytes and other submerged vegetation (Rodrigo et al., 2015; Baastrup-Spohr et al., 2016). The fact that submerged macrophytes were present in all the studied gravel pit lakes – also those only a few years old – suggests relatively fast colonisation.
Different responses of coexisting Chara species to foreseeable Mediterranean temperature and salinity increases
2017, Aquatic BotanyCitation Excerpt :On the contrary, C. hispida, with the absence of shoot elongation, would find it more difficult to inhabit brackish shoreline wetlands, and it would be restricted to unchanging clear and freshwater environments (Détriche et al., 2009; Soulié-Märsche, 2008). Puche and Rodrigo (2015) also reported a decrease in C. hispida biomass in a created pond fed by groundwater in the same wetland complex area (Albufera de València Natural Park; Rodrigo et al., 2015) under the scenario of a spring temperature increase and lower freshwater input to the pond, with the consequence of increased salinity. In fact, the historical sequence of species substitution in the Albufera de València coastal lagoon (based on the study of oospores from sediment cores) when this system changed from more saline water to brackish water (Rodrigo et al., 2010) seems to agree with our results.