جستجوی مقالات مرتبط با کلیدواژه « scale plots » در نشریات گروه « کشاورزی »

Zagross forests as the most extensive part of forests of Iran, retain important plant diversity. Vegetation knowledge is the base for ecological studies, management, and plant species conservation. Many diverse methods in vegetation studies have been proposed, based on the aims of study, kinds of vegetation, phonologic and taxonomic constraints, and financial and administrative possibility, which surveying is the most common. This study aimed to investigate the ability of modified multiscale Whittaker plots with random distribution in different vegetation types, in determining floristic composition.
In this study, floristic composition of Hashtad Pahloo forest catchment (8072 ha), contrary to common floristic studies, have been studied by sampling method using 21, 250 m2 Wittaker multiscale plots. Sampling plots were distributed randomly in four distinct vegetation types including pure oak type (Quercus brantii Lindl.), Mixed oak and Acer (Quercus brantii Lindl., Acer monspessulanum L.), Shrubs and cushion plants (Daphne mucronata Royle, Cotoneaster morulus Pojark), and Mountain grasslands (Ferulago angulata Boiss., Tanacetum polycephalum Sch. Bip) types. Collected plants species were identified using authentic references and their life forms were determined based on Raunkier classification. Also Chorological study were performed based on Zohari eco regional division. IUCN classification and red data book of Iran were used to define Conservative situation of plant species.
Results show that there are 211 species belong to 166 genus and 46 families in this landscape. Compositeae with 28 species (13.27%) were the biggest family. Irano-Toranian with 80 species (37.91%) and Mediterranean with 55 species (26.6%) were the most common chorologic types in this area. The most important life forms were Therophytes 88 species (43.9%), Geophytes 43 species (21.43%), Chamaephytes 25 species (13.2%), Hemicryptophytes 18 species (9.57%) and Phanerophytes 15 species (8.1%).
Comparison of the results of this study with earlier floristic study recently performed in this landscape revealed that random distribution of sampling plots in different vegetation types is able to identify common plant species while it needs less time and cost.

Studying the species diversity as a main part of biodiversity has great importance to detect changes in the ecosystems. Species diversity can be measured using transect and single-scale plot, nested methods and multi-scale plots. Modified Whittaker plot, Intensive modified Whittaker plot and a new C plot (introduced in this study) were used to measure species diversity in Karsank rangelands in Shahrekord province. The vegetation data was collected from sites with east and west aspects, and light and moderate grazing intensities. In each treatment (a combination of aspects with grazing intensities) three kinds of the studied plots were established with three replications using systematic random sampling. After collecting vegetation data, indices of diversity, richness and evenness of species were calculated using the Past software. Comparisons of species diversity obtained by different plots in different treatments were performed using ANOVA in SPSS software and graphs were plotted using Excel program. The results showed that diversity, richness and evenness indices obtained by various plots did not differ significantly (α= 5%), hence it can be concluded that their performances are relatively similar. Moreover, the numerical values of indices cannot be a convincing criterion for determining the suitable plot. Therefore their precision & accuracy in measuring plant diversity indices and the measurements speed can also be investigated to select appropriate plot in future studies.