a major part of the rangelands of iran are located in arid and semi-arid regions. in this climate, rainfall fluctuation is an important factor which affects vegetation and forage production. in dry years that rainfall decreases, surface vegetation and forage production is damaged. this study was conducted on semi-steppic rangelands of ardebil over nine years (1999-2007), to study of vegetation ...

in this investigation an attempt has been made to study the species composition, distribution and seasonal fluctuation of acarine community (arachnida: acari) in two undisturbed and well-vegetated plots located within padmaja naidu himalayan zoolo-gical park, darjeeling, india. the study continued for three consecutive years (january to december 1999–2001) revealed the presence of 10 acarine ge...

How to explain the effect of seasonal water transfer on the carbon stocks of Baiyangdian wetland is studied. The ecological model of the relationship between the carbon stocks and water depth fluctuation of the reed was established by using STELLA software. For the first time the Michaelis-Menten equation (1) introduced the relation function between the water depth and reed environmental carryi...

Activity of adult, female Chrysops variegatus was studied for 17 months near Aregúa, Paraguay. The population was sampled by walking along a forest path while swinging an insect net. Results of sampling indicated that this species followed no seasonal pattern of activity. Fluctuation in activity appeared to follow a 13-week cycle. Meteorological effects on activity were studied during 2 weeks o...

Milk has an important role as a vehicle for rural development. Many factors are implicated in milk value chain and marketability in Egypt such as milk production practices, unorganized farmer community, seasonal fluctuation both in production and consumption, financial aspects of dairying, role of middlemen, infrastructure, price fixation and role of government agencies. Many governmental regul...

The fluctuation of the population of Daphnia laevis in Lake Jacaré (Middle River Doce, Minas Gerais) was monitored monthly (at one point in the limnetic region) for six years (2002-2007) as part of the Program of Long-Term Ecological Research (LTER/UFMG). The following parameters were also monitored: water temperature, pH, electrical conductivity, dissolved oxygen, chlorophyll a, total phosphor...