The efficiency of energy transfer through food chains [food chain efficiency (FCE)] is an important ecosystem function. It has been hypothesized that FCE across multiple trophic levels is constrained by the efficiency at which herbivores use plant energy, which depends on plant nutritional quality. Furthermore, the number of trophic levels may also constrain FCE, because herbivores are less eff...

Shoot pruning of the woody components in simultaneous agroforestry systems with annuals and perennials enhances the services they provide to the ecosystem functions and to human livelihoods. These services include organic inputs, such as biomass and plant nutrients. Shoot pruning of the woody components is now an essential management practice in simultaneous agroforestry systems to avoid compet...

Communities of plants are thought to grow until they reach some limiting factor such as light, space, available nutrients or other limitation. Very often this limiting factor is a nutrient limitation. Therefore, if plants are provided with the essential nutrient they lack, they will expand their community’s biomass. This phenomenon is well studied in temperate communities. In those ecosystems, ...

The appearance and disappearance of NADH:nitrate reductase (NR) in the leaves of corn (Zea mays L. W64A x W182E) were studied using activity assays, an enzyme-linked immunosorbent assay (ELISA) and western blotting. N-starved, etiolated corn plants were treated with nutrients containing either 35 millimolar NH(4)-nitrate or K-nitrate and immediately thereafter given light. The curve for enhance...

The Çaygören Reservoir was sampled monthly from February 2007 to January 2009 at three stations to determine the relationships between the chlorophyll-a (Chl-a) dynamics and soluble reactive phosphorus (SRP), nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), water discharge, water transparency, water temperature (T), specific conductance (SC) and pH. Thermal stratification occurred in the re...

The Çaygören Reservoir was sampled monthly from February 2007 to January 2009 at three stations to determine the relationships between the chlorophyll-a (Chl-a) dynamics and soluble reactive phosphorus (SRP), nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), water discharge, water transparency, water temperature (T), specific conductance (SC) and pH. Thermal stratification occurred in the re...

The Zerebar Lake is a shallow freshwater lake located in the northwestern Iran. The lake is surrounded by three human activities: agriculture, tourism and dam. The present study aimed to investigate (1) which human activity has the greatest impact on eutrophication of the Zerebar Lake (2) If phytoplankton communities, as the indicator, are correlated with the human activities. Water samples wer...