Seasonal and long-term changes in surface cover of aquatic plants in a shallow pond, Ojaga-ike, Chiba, Japan

Abstract

Seasonal and long-term changes in surface cover of aquatic plants in a shallow pond, Abstract Seasonal changes in surface cover and long-term floral changes in aquatic plants of a shallow eutrophic pond, Ojaga-ike, as well as the phenology of each species, were studied . Out of ten floating-leaved and submerged plants, the following five species showed a change in surface cover during 1978 : Potamogeton crispus and Elodea nuttallii occupied 53 .5% of the total pond surface in May, Trapa natans and Nelumbo nucifera 79 .1% in July, N. nucifera and Hydrilla verticillata 62 .0% in September and N. nucifera 41 .2% in November . In addition to dramatic seasonal changes in surface cover, long-term floral changes occurred in this pond from 1971 onwards . While Nymphoides indica, Myriophyllum spicatum and H. verticillata decreased in number and in distribution ranges between 1971 and 1978, two newly established plants, N. nucifera and E. nuttallii, have now become dominant . The alteration in dominance may be due to water level fluctuations and interspecific competition for light . Seasonal changes in water quality during the study period are also summarized .

Presence of tropical hydrophytes in relation to limnological parameters - a study of two freshwater ponds in Kolkata, India

“…The other type was the occurrence of mixed communities of submerged flora (two to three species) together with floating-leaved (one to two species) and emergent (one to four species) forms (Philipose et al 1970, Gopal 1990. As found in this study, the mixed occurrence of all growth forms has also been widely reported in other tropical and subtropical ponds (Kunii & Maeda 1982, Gopal & Chamanlal 1991, Hussainy 1965, Nasar & Dutta Munshi 1974, Pandey et al 1988, Kunii 1991, Zambrano et al 1999.…”

“…Secchi disk visibility -The wide range of Secchi disk visibility values observed for V. spiralis ( Figure 1a) was similar to that reported by Kunii & Maeda (1982) for a subtropical pond with the same species as well as rich in other growth forms of aquatic vegetation. Thus tolerance of this species in low light is evident.…”

“…of chlorophyll-a was found to be similar to another subtropical pond with emergent species (Khondker & Kabir 1995) while the value was much lower when compared to a subtropical pond with all growth forms (Kunii & Maeda 1982). In turbid tropical ponds without aquatic vegetation wide fluctuations in chlorophyll-a values have been reported (Jana & Kundu 1993).…”

Changes in physicochemical and biological factors during regime shifts in a restoration demonstration of macrophytes in a small hypereutrophic Chinese lake

“…In addition, we selected two overwintering species, P. crispus and E. nuttallii, as the pioneer species for the reestablishing. This is also because that these plants are typically rapid colonizers (Simons et al, 1994), have a particularly strong positive effect on water transparency compared to other macrophytes (Van Donk and Van de Bund, 2002), and are inclined to multiply under cool weather conditions in eutrophic waters (Kunii and Maeda, 1982). Hence, choosing winter and early spring with relatively high transparency and low water level for the reestablishing should be appropriate; (2) an optimized strategy for macrophyte planting was adopted via a combination of different species.…”

Relationship between plant life forms and ecological indices in a lacustrine ecosystem

“…Kunt., and Ceratophyllum demersum L.) are found in abundance. Because of their competitiveness and adaptability, these species did not enable the development of other hydrophytes [33,34]. The above hydrophytes formed pure stands in our study site.…”