道路对三江源国家公园黄河源园区藏野驴和藏原羚种群数量及其栖息地的影响

为探究道路对三江源国家公园黄河源园区藏野驴(Equus kiang)和藏原羚(Procapra picticaudata)种群数量及其栖息地的影响,于2020年冷季采用截线取样法在黄河源园区进行实地调查.通过设置4种不同等级的道路情景,使用MaxEnt模型评价藏野驴和藏原羚的生境适宜性,模拟了不同等级道路变量情景下两种...

Effects of roads on the abundance and habitat of Tibetan wild ass and Ti-betan gazelle in the Yellow River Source Zone of Sanjiangyuan National Park

We sought to understand the effects of roads on the populations and habitat of Tibetan wild ass (Equus kiang) and Tibetan gazelle (Procapra picticaudata) in the Yellow River Source Zone of Sanjiangyuan National Park. We conducted a field survey to estimate population size, density and distribution of Tibetan wild ass and Tibetan gazelle in the region in autumn 2020 using a line transect sampling method. We then used the MaxEnt to assess habitat suitability of the two species under four different scenarios of road density and road type. The total length of the survey line was 1 320. 63 km, along which 2 231 Tibetan wild asses and 822 Tibetan gazelles were observed. The density of Tibetan wild ass was (1. 18 ±0. 34) individuals/km2 and the estimated abundance ranged from 2 400 to 7 632. The density of Tibetan gazelle was (0. 94 ±0. 14) individuals/km2 and the estimated abundance ranged from 1 765 to 3 219. MaxEnt predicted that the suitable habitat areas of Tibetan wild ass and Tibetan gazelle were 3 641. 34 km2 and 2 525. 18 km2, accounting for 19. 2% and 13. 3% of the entire Yellow River Source Zone, respectively. Distance to low-grade roads, annual precipitation, altitude and normalized difference vegetation index were the most important factors affecting habitat suitability for Tibetan wild ass.Distance to low-grade roads, altitude, aspect and slope were the most important factors affecting habitat suitability for Tibetan gazelle. The overlapping suitable habitat area of the two species was 2 240. 15 km2, accounting for 61. 5% and 88. 7% of the suitable habitat of Tibetan wild ass and Tibetan gazelle, respectively. The suitable habitats of Tibetan wild ass and Tibetan gazelle in autumn were mainly distributed in the central part of the Yellow River Source Zone. The road scenarios analysis indicated that:(1) the three scenarios including road variables resulted in varying degrees of habitat area loss and consequent population declines for both species when compared to the scenario with no roads. Scenarios with all road variables resulted in the smallest area of suitable habitat and the smallest populations for both species with 27. 2% and 42. 3% of suitable area lost for Tibetan wild ass and Tibetan gazelle respectively. (2) Different types of roads have different degrees of influence on the habitat area and populations of the two species. Low-grade roads cause greater habitat area loss and greater population declines for both species compared to highgrade roads. (3) The two species respond differently to road disturbance, with Tibetan gazelle suffering a greater loss of suitable habitat and experiencing a greater reduction in population size. This study provides evidence for ungulate conservation and roads managed on the Qinghai-Tibetan Plateau by quantitatively assessing the effects of different types of roads on the habitats and populations of two ungulate species.