Study On Bird Diversity And Heavy Metals Exposure Risk Assessment Of Common Species In Nanhaizi Wetland,Baotou

To study the bird community structure of the Nanhaizi Wetland Nature Reserve in Baotou and the effects of heavy metal pollution on birds,in order to better facilitate bird conservation and wetland management.This study investigated the bird resources of the wetland and assessed the risk of exposure to heavy metals for common species.The study of the bird community structure showed that(1)141 species of birds were recorded,belonging to 19 orders and 42 families,of which 11 species of birds were protected under National Class I,accounting for 7.80% of the total number of bird species,and 18 species of birds under National Class II,accounting for 12.77%;in terms of bird lineage affiliation,84 species of Palearctic species,three species of Oriental species and 38 species of widespread species were recorded.(2)The Shannon-Wiener Diversity Index and Pielou Index of the bird community showed a decreasing trend from 2014 to 2021.The monthly Shannon-Wiener diversity indices were highest in May and lowest in January,while the number of birds was highest in January and lowest in August.The diversity index follows the pattern of spring = summer > autumn > winter;the evenness index shows summer >spring > autumn > winter;the richness shows spring > summer > autumn > winter;and the total number of birds shows a pattern of winter > autumn > spring > summer.(3)Regression analysis showed a linear relationship between temperature and diversity;the diversity index was highest when precipitation was 80 mm,and temperature and precipitation were the key factors affecting waterbird diversity.Risk assessments of exposure to common species of heavy metals indicate that(1)the content of heavy metals in the environmental factors exceeded the Chinese standard,with water Cr and Hg levels being approximately 4 times and 20 times higher than the standard,respectively,and soil As levels being 5 times higher than that of the standard.In the myometrium of the mallard duck and ruddy shelduck,Ni,Pb and Cr elements all exceeded the standard to varying degrees.(2)Ni,Cr,and As accumulated predominantly in the lungs,and Pb and Hg accumulated in the liver.Five tissues were significantly enriched with each of these elements in the water,except for As.Finally,(3)the exposure doses of Hg and Cr in water and soil were higher than the daily tolerable doses for mallard ducks and ruddy shelducks,and the the highest hazard quotient(HQ)for Hg and all elements except Ni having a negative effect.