Does road construction have beneficial effects on vegetation biodiversity and tree regeneration in arid woodlands?

Abstract

The regeneration, plant diversity, and change of soil properties are the determining factors affecting the stability of natural forests. Road construction activities are considered among the most important contributing factors. This study was conducted to see if road construction has positive or negative effects on plant diversity, soil physicochemical properties, and tree regeneration in arid woodlands and fulfill the lack of information about road construction in arid woodlands. For this purpose, two roads were selected in the arid woodlands of Bushehr Province, Iran. Twenty‐four sampling plots with an area of 200 square meters were selected on the RE and in the forest interior around the studied roads. Plant species diversity, soil physiochemical properties, and tree regeneration were determined in the studied plots. Our result indicated 49 plant species belonging to 20 families in the studied sites. RE plots represented 37 species while plots in the forest interior represented 40 species. Ficus johannis, Ziziphus spina‐christ, Eryngium billardieri, Astragalus fasciculifolius, Medicago rigidula, Vicia peregrine, and Peganum harmala appeared only in the plots located at the RE. But Dicyclophora persica, Convolvulus acanthocladus, Capparis parviflora, Pulicaria aucheri, Senecio sp., Phlomis olivieri, Teucrium polium, Ziziphora tenuior, Salvia sp., Haplophyllum canaliculatum, Fumaria parviflora, and Scabiosa olivieri appeared only in the forest interior plots. Although no significant differences were observed for richness between the RE and forest interior plots, Shannon–Wiener diversity indices revealed significant differences between the studied groups. Therefore, the composition of the plant species was not the same in the RE and forest interior plots. M. rigidula and V. peregrine as nitrogen‐fixating and palatable plant species appeared in the RE plots but not in the interior plots. Moreover, medicinal plants like D. persica and C. acanthocladus, P. aucheri, H. canaliculatum, and P. olivieri were recorded in the interior plots. Besides, the tree regeneration and soil nutrients were significantly higher in the RE plots compared to the interior plots. Overall, road construction in arid woodlands results in plant and soil community changes. Nitrogen‐fixing species appeared by providing unfavorable environmental conditions for livestock grazing at the RE. Therefore, soil nitrogen and organic matter increased, and consequently, tree regeneration increased in the RE plots. In contrast, medicinal plants appeared in the interior plots, where grazing pressure was higher than in the RE plots. Medicinal plants probably produce some chemical components unfavorable for livestock grazing.