Effects Of Forest Restoration On Breeding Bird Diversity And Community Structure In The Xinglong Mountain,China

Forest restoration is a key means to reverse the ecosystem degradation caused by human activities worldwide.The proportion of plantation has significantly increased with the extensive implementation of ecological restoration projects in China,especially in the Loess Plateau.However,the effects of restoration for plantation and the secondary succession forest on biodiversity in the semi-arid area is still unclear.Here,we studied the effects of six different forest types on biodiversity,including primary Picea wilsonii forest,secondary mixed broadleaf-conifer forest,secondary broad-leaved deciduous forest,Rhododendron shurb,plantation of Larix principisrupprechtii and Pinus tabuliformis.Field investigation,acoustic monitoring and literature review were applied to compare the multidimensional diversity(species richness,phylogenetic and functional diversity),community structure and acoustic diversity of breeding birds in the Xinglong Mountain.We assessed the α diversity of bird species composition,nestedness and turnover of β diversity and their community assembly,and explored the variational characteristics of soundscape and its relationship with bird richness across the forest types.The main results are as follows:(1)A total of 93 breeding bird species were recorded,with a total 55 genera of 30 families for 10 orders.A total of 72 bird species accounted for 77.42% belonged to 40 genera of 21 families of Passeriformes,while 21 species belonged to 15 genera of 9families of non-Passeriformes,accounted for 22.58% of the total species.Phylloscopidae is the most species of Passeriformes accounting for 22.22% of the total,followed by Muscicapidae and Fringillidae.Accipitridae(8 species)and Columbidae(4 species)had the most species among non-Passeriformes.A total of 17 species were key protected wild animals in China,including Golden Eagle(Aquila chrysaetos)(Class I nationally recognized species)and Himalayan Vulture(Gyps himalayensis)of Near Threatened(NT)species by IUCN Red List.(2)The effect of plantations on bird diversity was limited compared with to that of secondary succession forest.Plantations have no significant gain on bird species richness,phylogenetic and functional diversity compared with primary and secondary forest,but the plantation of Larix principis-rupprechtii had higher performance than that of Pinus tabuliformis.Secondary coniferous and broad-leaved mixed forests,which have succeeded to the middle stage after selective logging,responded to the highest bird species diversity and functional richness,supporting Connells intermediate disturbance hypothesis.Two secondary forest types were no difference in phylogenetic and functional diversity compared to primary forest and had the most efficient for the utilization of the ecological space resources,indicating that the priority for conservation actions should be given to secondary and primary forest instead of plantation.(3)The differences in bird community composition were caused by nestedness component of β diversity.Community composition of the two secondary forest types was similar to that of the primary forest,and the plantation of Pinus tabuliformis was a subset of the other forest types.Rhododendron shrub,with the highest species turnover,was important for the maintenance of the unique species in mountain ecosystems.The highly concentrated phylogenetic and functional structure of Rhododendron shrub may indicate that high-altitude climate restriction played a key role for local environmental filtering on the bird community.Bird community assembly of Pinus tabuliformis was dominated by interspecific competition,and community assembly of other forest types were dominated by environmental filtering.(4)Sound landscapes revealed clear diurnal and habitat patterns across forest types in the semi-arid mountainous forest ecosystems,and vocal animal communities had diurnal and nocturnal activity rhythms.The peak of diel activity patterns was at dawn(5:00-8:00 a.m.),also known as the "dawn chorus of birds".Bird species richness was positively correlated with acoustic diversity index(ADI)and bioacoustic index(BIO),but negatively correlated with acoustic complexity index(ACI)and normalised difference soundscape index(NDSI).The ADI and BIO provide evidence for species diversity of secondary coniferous and broad-leaved mixed forests and primary Picea wilsonii,which supports the acoustic niche hypothesis.ADI and BIO were significant correlation with Muscicapidae richness during all daytime hours,while were significant with Phylloscopidae richness only at dawn.Taken together,the response of bird diversity to secondary succession forest was significantly higher than that to human active restoration forest,and the secondary coniferous and broad-leaved mixed forest supported the highest bird diversity.Bird community composition of Pinus tabuliformis was a nested subset of β diversity,and taxonomic diversity was significantly lower than that in plantation of Larix principisrupprechtii.From the perspective of providing habitat for biodiversity,conservation actions should be inclined to primary forest,secondary forest and Rhododendron shrub,even in the case of reforestation,our results suggest that Larix principis-rupprechtii should be preferred for afforestation species.This study explored the potential of passive acoustic monitoring for assessing biodiversity of forest ecosystems for the first time in the semi-arid area of the Loess Plateau in China.We found that ADI and BIO could be effective measures for rapid assessment of biodiversity in different forest landscapes in the future.Our results provided theoretical basis and scientific guidance for biodiversity conservation and forest restoration in semi-arid mountain of China.