“…The main mechanism underlying facilitation is the amelioration of extreme thermal conditions and protection from the strong desiccating winds by neighboring plants [8]. Since growth is not temperature-dependent in either focal species [29], neither plant species may benefit from this sort of thermal facilitation. Instead, we found that both plant species prefer low-lying areas with high soil moisture, indicating similar habitat requirements [25,42].…”
Section: Discussionmentioning
confidence: 99%
“…The Changbai Mountain Nature Reserve is located in Jilin province, Northeast China (Figure 1). It has five unique vegetation zones arranged vertically from low altitude to high altitude: a deciduous broad-leaved forest zone below 500 m; a mixed deciduous broad-leaved/conifer forest zone between 500 and 1100 m; a coniferous forest zone between 1100 and 1700 m; a mountain birch forest zone between 1700 and 2000 m; and a tundra zone above 2000 m [29]. The alpine tundra of the Changbai Mountains has a short growing season between June and September every year.…”
Section: Study Areamentioning
confidence: 99%
“…The root depth of R. aureum in monoculture community was about 16 cm, while the root depth of D. angustifolia in monoculture community was about 22 cm. The roots of the two focal species could be distinguished by color and texture: roots of D. angustifolia were white and smooth, while the roots of R. aureum were brownish or reddish with a woody texture [29]. We sorted roots to different fractions according to the root diameter: coarse roots (diameter > 3 mm), medium roots (1 mm < diameter ≤ 3 mm), and fine roots (diameter ≤ 1 mm) for R. aureum, and medium roots (1 mm < diameter ≤ 3 mm) and fine roots (diameter ≤ 1 mm) for D. angustifolia.…”
Alpine plant communities are highly sensitive to global warming. One of the consequences of the warming is encroachment by herbaceous plants from forests at low elevations into alpine ecosystems. In the Changbai Mountains, narrowleaf small reed (Deyeuxia angustifolia (Kom.) Y. L. Chang) from mountain birch forests encroached upward into alpine tundra, gradually replacing native tundra shrubs such as Rhododendron (Rhododendron aureum Georgi). How encroaching plants affect native plant communities is not fully understood. In this study, we analyzed above- and belowground biomass of alpine plant communities at five encroachment levels to investigate how biomass allocation changed at species and community scales. Our research showed that native plants are forced to change their morphology to cope with competition, at both above- and belowground levels, from encroaching plants. We found that (1) R. aureum increased the shoot height and leaf area in order to compete with D. angustifolia; (2) above- and belowground biomass of D. angustifolia increased while above- and belowground biomass of R. aureum decreased with increasing levels of encroachment; and (3) D. angustifolia encroachment reduced the total biomass of alpine tundra. Encroachment by herbaceous plants has a long-term negative impact on the ability of tundra plants to sequester carbon in the alpine tundra of the Changbai Mountains.
“…The main mechanism underlying facilitation is the amelioration of extreme thermal conditions and protection from the strong desiccating winds by neighboring plants [8]. Since growth is not temperature-dependent in either focal species [29], neither plant species may benefit from this sort of thermal facilitation. Instead, we found that both plant species prefer low-lying areas with high soil moisture, indicating similar habitat requirements [25,42].…”
Section: Discussionmentioning
confidence: 99%
“…The Changbai Mountain Nature Reserve is located in Jilin province, Northeast China (Figure 1). It has five unique vegetation zones arranged vertically from low altitude to high altitude: a deciduous broad-leaved forest zone below 500 m; a mixed deciduous broad-leaved/conifer forest zone between 500 and 1100 m; a coniferous forest zone between 1100 and 1700 m; a mountain birch forest zone between 1700 and 2000 m; and a tundra zone above 2000 m [29]. The alpine tundra of the Changbai Mountains has a short growing season between June and September every year.…”
Section: Study Areamentioning
confidence: 99%
“…The root depth of R. aureum in monoculture community was about 16 cm, while the root depth of D. angustifolia in monoculture community was about 22 cm. The roots of the two focal species could be distinguished by color and texture: roots of D. angustifolia were white and smooth, while the roots of R. aureum were brownish or reddish with a woody texture [29]. We sorted roots to different fractions according to the root diameter: coarse roots (diameter > 3 mm), medium roots (1 mm < diameter ≤ 3 mm), and fine roots (diameter ≤ 1 mm) for R. aureum, and medium roots (1 mm < diameter ≤ 3 mm) and fine roots (diameter ≤ 1 mm) for D. angustifolia.…”
Alpine plant communities are highly sensitive to global warming. One of the consequences of the warming is encroachment by herbaceous plants from forests at low elevations into alpine ecosystems. In the Changbai Mountains, narrowleaf small reed (Deyeuxia angustifolia (Kom.) Y. L. Chang) from mountain birch forests encroached upward into alpine tundra, gradually replacing native tundra shrubs such as Rhododendron (Rhododendron aureum Georgi). How encroaching plants affect native plant communities is not fully understood. In this study, we analyzed above- and belowground biomass of alpine plant communities at five encroachment levels to investigate how biomass allocation changed at species and community scales. Our research showed that native plants are forced to change their morphology to cope with competition, at both above- and belowground levels, from encroaching plants. We found that (1) R. aureum increased the shoot height and leaf area in order to compete with D. angustifolia; (2) above- and belowground biomass of D. angustifolia increased while above- and belowground biomass of R. aureum decreased with increasing levels of encroachment; and (3) D. angustifolia encroachment reduced the total biomass of alpine tundra. Encroachment by herbaceous plants has a long-term negative impact on the ability of tundra plants to sequester carbon in the alpine tundra of the Changbai Mountains.
“…The mean annual precipitation is 1340 mm. This precipitation mostly occurs during June to September, which account for about 80% of the yearly total (The Tianchi Meteorological Station is located in the tundra zone, 42°01'N, 128°05'E, 2623 m) (Zong et al, 2016). The surface is mostly covered by weathered alkaline trachyte and small amounts of volcanic ash (local term: trass).…”
Section: Study Areamentioning
confidence: 99%
“…Interactions between above-and below-ground biological communities are potential drivers of community and ecosystem dynamics (Wardle et al, 2004). To date, studies of changes in the tundra vegetation of the Changbai Mountains have focused on the herbaceous plant expansion pattern (Zong et al, 2013b(Zong et al, , 2016Jin et al, 2016b). Expansion of the herbaceous plant Calamagrostis angustifolia into tundra areas is thought to be related to climate change and vegetation succession (Xu and Zhang, 2010).…”
As one of the most sensitive regions to global climate change, alpine tundra in many places around the world has been undergoing dramatic changes in vegetation communities over the past few decades. Herbaceous plant species in the Changbai Mountains area have significantly expanded into tundra shrub communities over the past 30 yr. Soil microbial communities, enzyme activities, and soil nutrients are intertwined with this expansion process. In order to understand the responses of the soil microbial communities to such an expansion, we analyzed soil microbial community structures and enzyme activities in shrub tundra as well as areas with three different levels of herbaceous plant expansion. Our investigation was based on phospholipid fatty acid (PLFA) analysis and 96-well microtiter plates. The results showed that herbs have expanded greatly in the tundra, and they have become the dominant species in herbaceous plant expansion areas. There were differences for community composition and appearance among the shrub tundra and the mild expansion, moderate expansion, and severe expansion areas. Except for soil organic matter, soil nutrients were increased in herbaceous plant expansion areas, and the total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), and available phosphorus (AP) were greatest in moderate expansion areas (MOE), while soil organic matter levels were highest in the non-expanded areas (CK). The total soil PLFAs in the three levels of herbaceous plant expansion areas were significantly higher than those in the non-expanded areas, and total soil PLFAs were highest in the moderately expanded area and lowest in the severely expanded area (SEE). Bacteria increased significantly more than fungi and actinomycetes with herbaceous plant expansion. Soil hydrolase activities (β-1,4-glucosidase (βG) activity, β-1, 4-N-acetylglucosaminidase (NAG) activity, and acid phosphatase (aP) activity) were highest in MOE and lowest in the CK treatment. Soil oxidase activities (polyphenol oxidase (PPO) activities and peroxidase (PER) activities) were also highest in MOE, but they were lowest in the SEE treatment. The variations in total soil PLFAs with herbaceous plant expansion were mostly correlated with soil organic matter and available phosphorus concentrations, while soil enzyme activities were mostly correlated with the total soil nitrogen concentration. Our results suggest that herbaceous plant expansion increase the total soil PLFAs and soil enzyme activities and improved soil nutrients. However, soil microorganisms, enzyme activity, and nutrients responded differently to levels of herbaceous plant expansion. The soil conditions in mild and moderate expansion areas are more favorable than those in severe expansion areas.
Climate change and other global change drivers threaten plant diversity in mountains worldwide. A widely documented response to such environmental modifications is for plant species to change their elevational ranges. Range shifts are often idiosyncratic and difficult to generalize, partly due to variation in sampling methods. There is thus a need for a standardized monitoring strategy that can be applied across mountain regions to assess distribution changes and community turnover of native and non‐native plant species over space and time. Here, we present a conceptually intuitive and standardized protocol developed by the Mountain Invasion Research Network (MIREN) to systematically quantify global patterns of native and non‐native species distributions along elevation gradients and shifts arising from interactive effects of climate change and human disturbance. Usually repeated every five years, surveys consist of 20 sample sites located at equal elevation increments along three replicate roads per sampling region. At each site, three plots extend from the side of a mountain road into surrounding natural vegetation. The protocol has been successfully used in 18 regions worldwide from 2007 to present. Analyses of one point in time already generated some salient results, and revealed region‐specific elevational patterns of native plant species richness, but a globally consistent elevational decline in non‐native species richness. Non‐native plants were also more abundant directly adjacent to road edges, suggesting that disturbed roadsides serve as a vector for invasions into mountains. From the upcoming analyses of time series, even more exciting results can be expected, especially about range shifts. Implementing the protocol in more mountain regions globally would help to generate a more complete picture of how global change alters species distributions. This would inform conservation policy in mountain ecosystems, where some conservation policies remain poorly implemented.
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