Effect of highway construction on plant diversity of grassland communities in the permafrost regions of the Qinghai - Tibet plateau

Abstract

During 2002–2004, a broad-scale survey on the plant diversity of grassland communities along a natural elevation gradient in the permafrost regions of the Qinghai–Tibet plateau, China, was conducted to investigate the effect of highway construction nearly 30 years ago. Richness index was not significantly different among undisturbed communities (Kobresia pygmaea meadow, K. humilis meadow, Stipa purpurea steppe, Carex moorcroftii steppe), but significant differences (P < 0.05) were observed for evenness and diversity indices among four undisturbed communities. Three indices significantly decreased from communities 100 m (lightly disturbed communities), 200 m (undisturbed communities), and 50 m (severely disturbed communities) from the Qinghai–Xicang Highway, and three indices of severely disturbed communities were similar to that of 30 m communities (extremely-severely disturbed communities). Diversity and richness indices peaked at intermediate elevations of 4720 m in undisturbed communities and lightly disturbed communities, but were uniform in the severely disturbed communities and extremely-severely disturbed communities along with the increase of elevation. β-Diversity decreased in communities at 30, 50, and 100–200 m distance from the highway. This indicated that β-diversity of communities was enhanced with the increase of disturbance for each grassland type in the study region. Both undisturbed and disturbed communities showed the same changeable bell-shaped trend with elevation increase, increasing from 4320–4620 m, decreasing from 4720 to 4920 m, and peaking at 4620 to ~4720 m, indicating that elevation from 4620–4720 m was a transition zone in permafrost region.

Leaf Nitrogen and Phosphorus Stoichiometry of Plants from Natural and Restorable Communities at Lands Used for Qinghai—ktibet Highway Construction, China

“…At each survey site, four parallel plots with the size of 10 × 10 m were arranged perpendicularly to the highway at a distance of 100 m and 200 m, respectively. Plots at 100 m distance with moderate disturbance were defined as restorable plots and plots at 200 m without disturbance were defined as natural plots (Guo et al 2007a). For the restorable plots, no fertilizer was applied and no plant was planted, where present vegetation at the time of survey was the result of natural restoration, developing from original propagule and exotic plant invasion.…”

“…Ma et al (2004) have pointed out that the natural restoration duration of LUQHC for the alpine grassland is more than 20 years at the current environments by comparing coverage and plant species diversity between natural communities and restorable communities. The plant species diversity of restoroable communities at LUQHC showed a bellshaped trend as the elevation increases from 4320 m to 4920 m, peaking at 4620 to 4720 m (Guo et al 2007a), and the vegetation restoration at LUQHC in alpine steppe regions is better than that in alpine meadow regions after 25 years (Wang et al 2004). These fruitful studies shows that the restorable plant community and natural plant community are different among cover, height and plant composition (Guo et al 2007b, L i et al 2008, Mao et al 2013, and that have propose the natural restoration duration of vegetation at LUQHC.…”

“…The ways to restore vegetation generally consist of natural restoration and pasture establishment, among which the natural restoration is generally considered a cheap and effective way because it achieves the goal without human assistance through a relatively long time (Bradshaw 2000), and is proved to be successful in the vegetation restoration of mined land (Bradshaw 1997) and LUQHC (Wang et al 2004, Guo et al 2007a) when compared to pasture establishment. Ma et al (2004) have pointed out that the natural restoration duration of LUQHC for the alpine grassland is more than 20 years at the current environments by comparing coverage and plant species diversity between natural communities and restorable communities.…”

“…Constructing highway is one of widespread and common factors contributing to alpine grassland degradation (Guo et al 2007a), which develops big area land used for highway construction by removing the vegetation and topsoil on both sides of roadbed to construct roadbed (Mao et al 2013). As one of important highway network in the Qinghai-Tibet Plateau, the Qinghai-Tibet Highway construction is entirely anthropogenic disturbance for alpine grassland in the Qinghai-Tibet Plateau, resulting in big area Land Used for Qinghai-Tibet Highway Construction (LUQHC) on both sides of the Qinghai-Tibet Highway roadbed, where alpine grassland severely degrades.…”

Predicting long-term hydrological change caused by climate shifting in the 21st century in the headwater area of the Yellow River Basin

“…The HYRB is crucial to the Yellow River Basin (YRB), as it contributed nearly 40% water to the whole YRB with an area of only about 16% (Chu et al, 2018). It was reported that the HYRB is one of the high-altitude regions with the richest biodiversity in the world (Guo et al, 2004). Therefore, the specific ecosystem in this region is valuable and critical for the YRB, and even for the whole globe.…”