Investigation of plant biodiversity in an agricultural landscape (Case study: Dasht-e- Naz, Sari)

Over the past half century, intensive agriculture has increased dramatically, and agricultural landscapes have changed to simple with low cover as single crop systems similar to semi-natural habitats. This trend has led to a sharp decline in biodiversity and a reduction in the provision of ecosystem services to agriculture. It has been confirmed that among ecosystem services, pest and weed control and pollination have significant impacts on global agricultural production. This study aimed to investigate the plant biodiversity of wheat, rapeseed, barley and triticale ecosystems in an agricultural landscape (Dasht-e- Naz Sari).

This experiment was carried ou as unbalanced completely randomized design in an agricultural landscape located in Dasht-e- Naz, Sari (Mazandaran province), during crop year 2019-2020. In this study, 26 farms were selected from different parts of autumn crops (rapeseed, wheat, barley and triticale). Sampling of plant biodiversity was performed based on W pattern with 0.5 × 0.5 m2 quadrate. The samples were transferred to the agronomical research laboratory of Gorgan University of Agricultural Sciences and Natural Resources and the flora was determined by genus and species. Then, bidiversity indices including Shannon-Weiner, Margalef, Menhinick, Simpson, Uniformity and Sorenson were calculated using the related equations. In final, based on the results, biodiversity status in the agricultural landscape was analyzed acorrding to status of landscape components including the type ecosystems, corridor, border, etc.

In this study, 25 plant species from 14 plant families were identified that 10 species belonged to narrow-leaved and 15 species belonged to broad-leaved. Among the identified species, Rapistrum rugosum, Avena ludoviciana, Phalaris minor and Cirsium arvense were the most abundant. The results showed that the plant biodiversity in this landscape was in a favorable condition based on Shannon-Weiner index, so that this index for triticale, barley, rapeseed and wheat plots were 2.64, 2.52 and 2.39 and 2.38, respectively. The amount of Menhinick index for autumn crops of rapeseed, barley, wheat and triticale was as 2.86, 2.85, 2.45 and 2.32, respectively. Also, the highest Simpson index for rapeseed, barley, wheat and triticale plots was equal 0.068, 0.047, 0.070 and 0.052, respectively. Based on our results, the highest similarities according to Sorenson index were related to triticale (1), barley (0.95), wheat (0.95) and rapeseed (0.93), respectively.

In general, the consumption of manure in some plots, the location of streams and barren lands in the margins of the plots and corridor of trees as windbreak, could affect on biodiversity of the surveyed landscape. The results of this study can be useful for comprehensive weed management program and making decision about control or improve ecosystem services through plant biodiversity.Keywords: Agricultural landscape, Biodiversity, Ecosystem Services.