| Passerines are small medium size songbirds generally with numberous species and and large population size, which can occurs in almost all kinds of terrestrial habitats. There are more than approximately 5400 species of 100 families in Passerifomes, one of the most complicated taxa of birds, which account for more than half of the species number of all birds. Passerines play an important role in pest control, seeds spread and pollen dispersal. Hence, they are considered as an indicative taxon of the condition of ecosystems.Based on a survey on passerines conducted from May 2012 to February 2015 in Qinling Mountain areas, we made a concentrated analysis on the distribution changes since 1973. The result provides fundamental data for the protection of wildlife resource, and for future surveys on the avifauna in Qinling Mountain areas. The specific results are shown below:The composition of avifauna in Qinling Mountain areasThere is a total of 495 bird species, belonging to 18 orders,69 families and 218 genus in our study areas. Of these species,9 species were listed as the first-class national protected animals, accounting for 1.82%. The species number of breeders was 312 (with 194 residents and 118 summer residents), of which 111 species belong to Palearctic realm,156 species to Oriental realm, and 45 species to Cosmopolitan species, accounting for 35.58%,50.00% and 14.42%, respectively. A total of 35 orders and 288 passerins were recorded which account for 75.61% of the total.Avifauna characteristic of Passeriformes in different geographical units of Qinling Mountain areasOf the 288 passeriness, there are 141 residents,76 summer residents,16 winter visitors,52 passengers and 2 vagrants, accounting for 49.13%,27.53%,5.55%,18.05% and 0.69%, respectively. A total of 271 summer breeders (76.66% of the total) consist of 90 Palearctic realm species,115 Oriental realm species and 12 Cosmopolitan species, accounting for 41.47%,53.00% and 5.53%, respectively.On the basis of the classification of the national geographical units, our study areas are dividied into three units:Weihe River Valley, Qinling Mountain and Hanjing Basin. The Qinling mountain unit is further dividied into two subunits:south slope and north slope due to the great differences in factors of geography, climate and vegetation. The avifauna of the passerines in Qinling Mountain unit is highlighted as follows.(i) Weihe River ValleyA total of 102 passerines were recorded in this unit which include 59 residents (57.84%),14 summer residents (13.73%) and 26 winter visitors (25.49%). Of the 73 breeders, there are 43 Palearctic realm species,26 Oriental realm species and 4 Cosmopolitan species, accounting for 58.90%,35.62% and 5.84%, respectively.(ii) Qinling MountainsMost of passerines occur in Qinling Mountain areas, in which they were apparently distributed along the altitudinal gradients. The avifauna in different altitudinal zones in north slope is described as follows.①The foothill zone (400-780 m)A total of 121 passerines only secondary to the lower part were recorded in the zone. Of these species, there are 69 Palearctic realm species (61.12%),31 Oriental realm speies (28.00%) and 12 Cosmopolitan species (10.88%).② The lower elevation zone (780-2,200 m)A total of 176 passerines (62.63%) were recorded in the altitude zone, where 143 breeders (81.25%) consist of 84 Palearctic realm species (58.96%),43 Oriental realm species (30.00%) and 12 Cosmopolitan species (9.14%).③ The medium elevation zone (2,200-2,730 m)There are 64 passerines (22.78%) recorded in this zone where 54 breeders (84.38%) composed of 31 Palearctic realm species (57.41%),20 Oriental realm species (37.04%) and 3 Cosmopolitan species (5.56%).④The higher elevation zone (2,730-3,400 m)38 passerines (13.52%) were found in the zone and most of them (35 species, 92.11%) are summer breeders. Of these breeders, there are 20 Palearctic realm species (57.14%) and 15 Oriental realm species (42.86%).⑤ The mountaintop zone (>3,400 m)Only 20 passerine breeders (7.12%) occurred in the zone consisted of 11 Palearctic realm species (55.00%) and 9 Oriental realm species (45.00%).(iii) Hanjiang BasinA total of 58 passerines recorded include 21 residents (36.21%),12 summer residents (20.69%),Of the 32 breeders, there are 12 Palearctic realm species (37.50%), 15 Oriental realm species (46.88%) and 5 Cosmopolitan species (15.63%).Number changes of passerine species in Qinling Mountain areasIn combination of published information relevant to our study areas, we conclude that the species number of passerines increased from 208 to 288 species since 1970s. Accordingly, the species number in agricultural area increase from 78 to 148, from 108 to 176 in mixed coniferous and broad-leaved forests, from 35 to 38 in subalpine coniferous forests, and from 7 to 20 in alpine scrubs and meadows. Whereas the species number in birch forests declined from 95 to 64 species.The reasons for changes of passerine avifaunaOur results showed that some Oriental realm species such as Pycnonotus sinensis, Spizixos semitorques, Terpsiphone paradisi and Pericrocotus ethologus gradually spread to Palearctic area, and some species in lower elevation zones expanded to higher elevation regions. The distribution changes may be contributed to global warming, especially in the northern-west part of China which may force some passerines to expand to north areas or higher elevation regions to seek for more suitable habitats. In fact that the global warming may lead to changes of the vegetation types in different altitudinal zones and northward dispersal extension, then resulting in series of reactions of ecosystem. The ranges expanded through the process of seeking for suitable habitats and food resource. In addition, the global warming may exert a profound influence on the time span of migration and witering regions of the passerines. |
PDF Full Text Request