Surveys to detect the presence or absence of endangered species may not consistently cover an area, account for imperfect detection or consider that detection and species presence at sample units may change within a survey season. We evaluated a detection–nondetection survey method for the federally endangered golden-cheeked warbler (GCWA) Dendroica chrysoparia. Three study areas were selected ...

the purpose of this research is investigation of relationship between vegetation cover and soil characteristics and determination of the most important soil factor that effects on quantity variations and kinds of vegetation cover in the study area. the study area is located in west of tehran province and south eastern of hashtgerd, next to najm-abad village. after field study, the index vegetat...

The rangeland in the Khangai mountain region in Mongolia has degraded for the last decades mainly because of overgrazing and climate change. Livestock production is important part of the economy and is based on natural rangeland. In this research we seek to elucidate the influence of five years (2004-2009) of protection from grazing on vegetation cover of different degradation levels of Fes...

In this paper we examine ways to verify reference nets, a class of high level Petri nets supported by the Renew tool. We choose to restrict reference nets to hypernets, another nets-within-nets model more suitable for verification purposes thanks to an expansion toward 1-safe Petri nets. The contribution of the paper is the implementation of such analysis techniques by means of a Renew plugin. ...

relationships between soil factors and vegetation types in playa of damghan was investigated. six vegetationtypes including artemisia.sieberi, arundo. sp, artemisia.sieberi-peganum.harmala, alhagi.cammelerom,artemisia.sieberi-petropyron.sp, tamarix.passerinoides-halocnemum strobilaceum. one bare land was recognized inthe study area and the research was conducted within mentioned types. canopy p...

1. introductionhumans have actively managed and transformed the world’s landscapes for millennia. after the industrial revolution (between 1820 and 1840) with increase in sanitation, food security and quality of life the human population increased tremendously. urbanization, the demographic transition from rural to urban, is associated with shifts from an agriculture-based economy to mass indus...