land use change effects from rural to urban on bird diversity: A case study of Isfahan

Abstract

Introduction: Urbanization is considered the most important extinction driver of various
fauna and flora species in the present century due to the degradation of habitat quality and
its fragmentation. Therefore, investigation of changes in the land use land cover mosaic can
provide useful information about the alteration of ecological processes, especially changes
in bird diversity in urban landscapes.
Materials & Methods: Bird survey was carried out from April to May 1400 between 8 and
11 am with three repetitions at 55 points located on 11 transects (5 points per transect).
Transects and points were selected by examining land use and land cover changes on the
rural-urban gradient. Then, 10 variables related to the area, mean distance and density of
green cover, road network and habitat were computed in 4 circular buffers with radii of 750,
1500, 2250 and 3000 at each point of bird observation to assess their relationship with the
Shannon diversity index using the multiple linear regression model.
Results: 2085 birds belonging to 46 bird species were observed. The domestic sparrow was
found as the most abundant bird species with 1381 individuals. Among the independent
parameters, percentage of green cover in buffer 1500 m, percentage of road cover in buffer
750 m, area of the nearest green cover, distance to the nearest green cover and mean distance
to the nearest green cover in buffer 2250 m as variables were entered in the regression
model (r2 = 0.64) as predictors of diversity Shannon.
Conclusion: The findings of this study showed that the area of small green spaces, their
long distance from each other and the high density of the road network are the most
important factors in reducing the presence and diversity of bird species in the urban
environment. Although areas close to the urban physical border showed higher bird
diversity, their sharp decline toward the city center could be offset by accurate locating of
urban green parks and reduction of traffic effects in nearby areas.