in arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. a study was done to analyze the effects of grazing on plant species diversity and plant functional types‘ (pfts) diversity of arid and semi-arid rangelands. we analyzed plant richness and diversity data from 75 sa...

abstract this paper carried out to study determinants of willingness to pay and ecotourism value of tandoreh natioral park using cross section data of 144 households of dargaz and ghochan and contingent value method and logit model in 2008. results showed that age and entrance offer have negative effect and income have positive effect on willingness to pay for ecotourism in tandoreh natioral pa...

Alarm-calling behaviour is common in many species that suffer from predation. While kin selection or reciprocal altruism are typically invoked to explain such behaviours, several authors have conjectured that some alarm calls may instead be costly signals sent by prey to inform approaching predators that they have been detected. We develop a general game-theoretical model, the watchful babbler ...

Reclaimed wastewater for irrigation is an opportunity for recovery of this natural resource. In this study, microbial risk from the use of treated wastewater for irrigation of recreational parks in the city of Chihuahua, evaluating the effect of distribution distance, season, and presence of storage tanks, was analyzed. Escherichia coli, Salmonella, and multidrug-resistant bacteria were recover...

Multi-players dynamic game between government, parks managers and visitors is proposed in this paper to find out which party should invest money to visitor education and their optimal investment strategies. The game reveals that government should invest a lot of fund to helping the park managers to develop proper visitor education programmes when the visitor education the visitor education mark...

non-parametric method to uncover periodic patterns of space use in animal tracking data” Guillaume Péron, Chris H. Fleming, Rogerio C. de Paula, and Justin M. Calabrese Conservation Ecology Center, Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Rd., Front Royal, VA 22630 Department of Biology, University of Maryland College Park, College Park, Maryland 20742 ...