Factors structuring aquatic macrophytes.

Abstract

Aquatic macrophytes are a key component of freshwater ecosystems, providing habitats for aquatic organisms, and play an integral role in food webs and nutrient cycles. Understanding the factors that influence macrophyte growth, distribution, structure and community composition is indispensable for their integrated management, which are explored in this chapter. Among these are biotic (herbivory, macrophyte properties and competition and pathogens and diseases) and abiotic (water chemistry including temperature, substrate composition/embeddedness and hydrological conditions) factors. Anthropogenic stressors further drive these biotic and abiotic factors individually or in combination, causing either the extinction of important native macrophytes or the uncontrolled proliferation of macrophytes, usually invasive alien species, which has been recognised as an important issue of aquatic ecosystem management in freshwater systems globally. Among the notorious aquatic macrophytes of global concern are the invasive water hyacinth (Pontederia crassipes) and giant salvinia (Salvinia molesta), which have detrimental impacts in invaded freshwater systems. The global problem of nuisance macrophytes needs to be holistically handled at all levels to prevent ecological and socioeconomic impacts associated with their proliferation. Solutions to curb the nuisance growth of aquatic macrophytes include mechanical removal, biological control and chemical treatment although integrated control is the most cost-effective control option. The control efforts need to be integrated at catchment and regional scales, facilitating the integration and partnerships of institutions to ensure functional aquatic systems and conservation of global biodiversity.