BACKGROUND AND AIMS The genus Leiothrix (Eriocaulaceae) is restricted to South America and contains 37 taxa. The genus is most species-rich in the mountains of Minas Gerais, where 25 species occur, 19 of them in the Serra do Cipó. Leiothrix taxa that inhabit different microhabitats exhibit a number of reproductive modes. Rhizomatous taxa produce seeds plentifully; therefore, this group were def...

tragacanth gum is one of the most important medicinal and industrial productsof rangelands and is obtained from the incision of gum tragacanth-producing astragalusincluding astragalus keyserlingii. the conservation of astragalus species in rangelandshas a special place in terms of economic profit and soil conservation. the increase in priceof gum tragacanth in recent years and more attention of...

estimating unsampled points for varying sampling intervals and densities was calculated (Webster et al., 1989). Pasturelands are inherently variable. It is this variability that makes The reflectance data measured in the Webster et al. sampling as well as characterizing an entire pasture difficult. Measurement of plant canopy reflectance with a ground-based radiometer (1989) study was optimal i...

abstract. rangeland vegetation dynamics encompass all processes of changes in vegetation composition and structure over time. investigating the rangeland ecosystem dynamics makes it possible to determine the effects of climatic and management conditions on qualitative and quantitative changes of the vegetation in a specific period of time. accordingly, data collection and measurements for evalu...

Conversion of tropical forests into agriculture may present a serious risk to amphibian diversity if amphibians are not able to use agricultural areas as habitat. Recently, in Xishuangbanna Prefecture, Yunnan Province - a hotspot of frog diversity within China - two-thirds of the native tropical rainforests have been converted into rubber plantation agriculture. We conducted surveys and experim...

This study evaluated the positioning accuracy of moving forest harvesters using global navigation satellite system (GNSS) signals under a canopy, and developed approaches for forecasting mature spruce canopy cover. Real-time kinematic with Trimble R12 receiver on top harvester achieved high accuracy, 86% observations meeting maximum precision 8 mm. However, presence cover hampered GNSS’s perfor...

We test the performance of two models that use mammalian communities to reconstruct multivariate palaeoenvironments. While both models exploit the correlation between mammal communities (defined in terms of functional groups) and arboreal heterogeneity, the first uses a multiple multivariate regression of community structure and arboreal heterogeneity, while the second uses a linear regression ...

This study was conducted to investigate the effect of ecological factors on distribution, presence and absence of species Ferula ovina and F. persica in the semi-arid rangelands of Zanjan province, Iran in 2015. The locations of ten 4m2 plots with 15m spacing on three 150 m long transects were systematically randomized and determined in each key area within each hab...

In the last two centuries, European fire suppression practices have produced increases in vegetation density and canopy cover in many landscapes. Potentially, increases in canopy cover could negatively affect small populations of nocturnal reptiles that use sun-exposed shelters for diurnal thermoregulation. We hypothesized that vegetation encroachment over rock outcrops might partly explain the...