On two methods to estimate production of Eichhornia crassipes in the eutrophic Pampulha reservoir (MG, Brazil)

Abstract

This paper deals with variations in biomass and in the production of Eichhornia crassipes (water hyacinth) in a eutrophic tropical reservoir. Net production was assessed by both a traditional method and a demographic approach. The initial biomass ranges from 96 g DW.m -2 to a maximum of 2027 g DW.m -2 . Net production estimates varied greatly according to which method was used to calculate them (traditional: 20.6 ton DW.hectare -1 .year -1 , demographic: 226.9 ton DW.year -1 ).Key words: Eichhornia crassipes (water hyacinth), biomass production, modular demography, macrophytes. RESUMO Sobre dois métodos para estimar a produção de Eichhornia crassipes no reservatório eutrófico Pampulha (MG, Brasil)Este estudo mostra as variações da biomassa e da produção de Eichhornia crassipes em um reservatório eutrófico tropical. A produção líquida foi estimada por intermédio do método tradicional e do demográfico. A biomassa inicial de 96 g PS.m -2 chegou ao máximo de 2.027 g PS.m -2 A produção líquida variou de acordo com o método utilizado para sua estimativa (tradicional: 20,6 ton PS. ha -1 .ano -1 , demográfico: 226,9 ton PS.ano -1 ).Palavras-chave: Eichhornia crassipes (aguapé), produção de biomassa, macrófitas, método demográfico.

Population dynamics of Eichhornia crassipes (C. Mart.) Solms in the Nile Delta, Egypt

“…The maximum total biomass of water hyacinth, as indicated in the present study (109 t/DM/ha), was lower than that in some tropical and sub‐tropical countries such as Brazil (203 t/DM/ha: Greco & Freitas ) and Mexico (284 t/DM/ha: Gutiérrez et al ). The high biomass in these tropical and sub‐tropical countries could be a result of favorable conditions for its growth because these Meso‐American countries represent the native range of its distribution (Shaltout ).…”

“…The growth pattern of water hyacinth in the Nile Delta was similar to that of the same species in Brazil (Greco & Freitas ), Mexico (Gutiérrez et al ), the USA (Akbay et al ) and China (Liu et al ). In the Nile Delta, the total biomass of water hyacinth reached peak values in August, which differs from the study of Center and Spencer (), who reported that the total biomass of water hyacinth growing in Lake Alice (Florida, USA) peaked in mid‐June and gradually declined thereafter.…”

“…Increasing plant density results in an increase of self‐shading (Gopal ) causing senescence of lower leaves (Luu & Getsinger ). Moreover, overcrowding of plants reduced leaf production and longevity of the leaves (Center & Van ; Greco & Freitas ). The mean dry matter of individuals was negatively correlated with individual density, which reflects the effectiveness of intra‐specific competition, where individual average weight decreased as density increased.…”

Functional linkage between N acquisition strategies and aeration capacities of hydrophytes for efficient oxygen consumption in roots

“…Species with a high aeration capacity and a powerful convective gas‐flow system, including P. australis , T. angustifolia and Eleocharis sphacelata (Armstrong et al , Brix et al ), are widely distributed in various habitats such as oligo‐mesotrophic fens (Wheeler and Proctor , Nakamura et al , Sorrell and Hawes ), meso‐eutrophic ponds (Hejny and Husak ), deep anoxic lakes dominated by NH (Yamasaki , Weisner and Strand , Wheeler and Proctor , Inoue and Tsuchiya , Sorrell and Hawes ) and NO‐abundant oxic sites at shallow‐lake fringes and meadows (Kühl et al ). In contrast, species with a low aeration capacity, such as Z. latifolia , Eichhornia crassipes , Schoenoplectus tabernaemontani , Trapa natans and Scirpus tabernaemontani , tend to appear only in eutrophic and anaerobic habitats (Center and Spencer , Yamasaki , Kurihara and Ikusima , Greco and De Freitas , Anderson and Mitsch , Xiao et al ).…”

Large-Scale Green Liver System for Sustainable Purification of Aquacultural Wastewater: Construction and Case Study in a Semiarid Area of Brazil (Itacuruba, Pernambuco) Using the Naturally Occurring Cyanotoxin Microcystin as Efficiency Indicator

“…E. crassipes has the enormous advantage of changing water parameters, most notably reducing the water temperature [29]. According to Greco and de Freitas [30], this macrophyte grows best at high temperatures, as experienced in Brazil. E. crassipes has previously been tested for the phytoremediation of urban wastewater [31], cyanide [32], and mercury [33] and has been assessed as useful and appropriate for such purposes.…”