Altitudinal patterns of maximum plant height on the Tibetan Plateau (original) (raw)
Related papers
Plant Ecology, 2009
When elevational gradients include combinations of different climatic gradients, such as a decline in temperature combined with an increase in moisture, vegetation and plant trait responses are difficult to explain. Here, we used plant species richness and morphometric traits data across steep elevational gradients in the Helan Range of Northwestern China in an attempt to separate general trends (temperature related) from regional peculiarity (moisture related). Based on the floristic data of the Helan Range as well as plot-based data, both drought (at low elevation) and low temperature (high elevation) are associated with low species richness presumably also explaining the peak in diversity at mid-elevation, where climatic conditions are moderate. However, this mid-elevation peak in diversity is not mirrored in trends of plant traits such as leaf size and inflorescence size, which show either unidirectional trends or no change with elevation (with impacts of drought and low temperature perhaps gradually replacing each other). Our analysis illustrated the taxonomic and plant functional type (PFT)-related biases in functional trait studies and showed that consistent patterns only emerge after careful data stratification, with taxonomy (family level) holding more promises than PFTs. Inflorescence size increased with elevation in major insect-pollinated families, a trend not seen in wind-pollinated (graminoid) families. However, the reproductive effort expressed as inflorescence/leaf length ratio increases with elevation in the majority of plant families, irrespective of their pollination system. The fact that these biometric responses to elevation do not correlate with responses in species richness (which peaks at mid-elevation) may reflect contrasting drivers of trait selection and biodiversity. Based on our plot-based data, this analysis also confirmed the usefulness of floristic archive data for testing ecological theory related to elevational gradients.
A test of the generality of leaf trait relationships on the Tibetan Plateau
New Phytologist, 2006
Leaf mass per area (LMA), nitrogen concentration (on mass and area bases, N mass and N area , respectively), photosynthetic capacity ( A mass and A area ) and photosynthetic nitrogen use efficiency (PNUE) are key foliar traits, but few data are available from cold, high-altitude environments.
Evolutionary history and underlying adaptation of alpine plants on the Qinghai-Tibet Plateau
Journal of Systematics and Evolution, 2014
As the highest and largest plateau in the world, the Qinghai-Tibet Plateau, with its numerous endemic species, is one of the important alpine biodiversity hotspots. Only recently have the evolutionary histories and underlying adaptations of these alpine plants become clear, through research mostly based on testable experiments and analyses. In this issue, we collected a total of 13 papers related to such aims. In addition, we selected a few published papers to highlight the major findings in the recent past. We also outlined the outlook and direction of future research.
2020
How and why species range size varies along spatial gradients is fundamental yet controversial topics in biogeography. To advance our understanding on these questions and to provide insight into biological conservation, we assessed the elevational variations in vascular plants range size for different life form and biogeographical affinities, and explored the main drivers underlying above variations in the longest valley in China's Himalayas---the Gyirong Valley. Elevational range sizes of vascular plants were documented by 96 sampling plots along 12 elevational bands of 300-m ranging from 1800 to 5400 m above sea level. We assessed the elevational variations in range size by averaging the range size of all species within each elevational band. We then related range size to climate, disturbance, competition factors and the mid-domain effect, and explored the relative importance of aforementioned factors in explaining the range size variations using the Random Forest model. Total...
Frontiers in Plant Science
Recently, the "mountain-geobiodiversity hypothesis" (MGH) was proposed as a key concept for explaining the high levels of biodiversity found in mountain systems of the Tibeto-Himalayan region (THR), which comprises the Qinghai-Tibetan Plateau, the Himalayas, and the biodiversity hotspot known as the "Mountains of Southwest China" (Hengduan Mountains region). In addition to the MGH, which covers the entire life span of a mountain system, a complementary concept, the so-called "flickering connectivity system" (FCS), was recently proposed for the period of the Quaternary. The FCS focuses on connectivity dynamics in alpine ecosystems caused by the drastic climatic changes during the past ca. 2.6 million years, emphasizing that range fragmentation and allopatric speciation are not the sole factors for accelerated evolution of species richness and endemism in mountains. I here provide a review of the current state of knowledge concerning geological uplift, Quaternary glaciation, and the main phylogeographic patterns ("contraction/recolonization," "platform refugia/local expansion," and "microrefugia") of seed plant species in the THR. In addition, I make specific suggestions as to which factors future avenues of phylogeographic research should take into account based on the fundamentals presented by the MGH and FCS, and associated complementary paradigm shifts.
Journal of plant research, 2021
Traits are the primary attributes that distinguish a species niche. Species and higher taxa are part of a structured phylogeny, and variation in plant traits depends on lineage as well as on environmental conditions. Therefore, it is crucial to investigate linkages between taxonomic identity, shared ancestry, and environment for understanding the variation in leaf traits. We investigated the evolutionary relationships, based on multiple gene sequences among 26 plant species sampled along an elevational gradient from 650 to 3600 m a.s.l. in the central Himalaya. We tested for the phylogenetic signal based on three different measures in 10 leaf traits having a significant association with the resource acquisition-conservation trade-offs axis and influencing plant growth, development, and ecological performance. We further assessed the role of elevation and growth forms as the potential drivers of leaf traits variation while controlling for phylogeny. 5 out of 10 leaf traits showed sig...
Oecologia, 2010
We tested three hypotheses related to the functioning of mountain plants, namely their reproductive eVort, leaf surface structure and eVectiveness of CO 2 assimilation, using archive material from contrasting elevations. Analysis of elevational trends is at risk of suVering from two major biases: a phylogenetic bias (i.e. an elevational change in the abundance of taxonomic groups), and covariation of diVerent environmental drivers (e.g. water, temperature, atmospheric pressure), which do not permit a mechanistic interpretation. We solved both problems in a subcontinental survey of elevational trends in key plant traits in the European Alps and the high Arctic (northern Sweden, Svalbard), using herbarium samples of 147 species belonging to the genera Carex, Saxifraga and Potentilla. We used both species and phylogenetically independent contrasts as data points. The analysis revealed enhanced reproductive eVorts at higher elevation in insect-pollinated taxa (not in wind-pollinated taxa), no increase in leaf pubescence at high elevation (as is often assumed), and a strong correlation between 13 C discrimination and elevation. Alpine taxa operate at a smaller mesophyll resistance to CO 2 uptake relative to diVusive resistance (stomata). By comparison with congeneric low altitude polar taxa (low temperature, but high atmospheric pressure), the response could be attributed to the elevational decline in atmospheric pressure rather than temperature (a mean increase in 13 C by 1.4‰ km ¡1). The signal is consistent within and across genera and within species, suggesting rapid adjustment of leaf physiology to reduced partial pressure of CO 2. These results oVer answers to long-debated issues of plant responses to high elevation life conditions.
Multi-trait interactions, not phylogeny, fine-tune leaf size reduction with increasing altitude
Annals of botany, 2011
† Background and Aims Despite long-held interest, knowledge on why leaf size varies widely among species is still incomplete. This study was conducted to assess whether abiotic factors, phylogenetic histories and multi-trait interactions act together to shape leaf size. † Methods Fifty-seven pairs of altitudinal vicariant species were selected in northern Spain, and leaf area and a number of functionally related leaf, shoot and whole plant traits were measured for each pair. Structural equation modelling helped unravel trait interactions affecting leaf size, and Mantel tests weighed the relative relevance of phylogeny, environment and trait interactions to explain leaf size reduction with altitude. † Key Results Leaves of highland vicariants were generally smaller than those of lowlands. However, the extent of leaf size reduction with increasing altitude was widely variable among genera: from approx. 700 cm 2 reduction (96 % in Polystichum) to approx. 30 cm 2 increase (37 % in Sorbus). This was partially explained by shifts in leaf, shoot and whole plant traits (35-64 % of explained variance, depending on models), with size/number trade-offs more influential than shifts in leaf form and leaf economics. Shifts in traits were more important than phylogenetic distances or site-specific environmental variation in explaining the degree of leaf size reduction with altitude. † Conclusions Ecological filters, constraints due to phylogenetic history (albeit modest in the study system), and phenotypic integration contribute jointly to shape single-trait evolution. Here, it was found that phenotypic change was far more important than shared ancestry to explaine leaf size differences of closely related species segregated along altitudes.
Nature Communications
Studies along elevational gradients worldwide usually find the highest plant taxa richness in mid-elevation forest belts. Hence, an increase in upper elevation diversity is expected in the course of warming-related treeline rise. Here, we use a time-series approach to infer past taxa richness from sedimentary ancient DNA from the south-eastern Tibetan Plateau over the last ~18,000 years. We find the highest total plant taxa richness during the cool phase after glacier retreat when the area contained extensive and diverse alpine habitats (14–10 ka); followed by a decline when forests expanded during the warm early- to mid-Holocene (10–3.6 ka). Livestock grazing since 3.6 ka promoted plant taxa richness only weakly. Based on these inferred dependencies, our simulation yields a substantive decrease in plant taxa richness in response to warming-related alpine habitat loss over the next centuries. Accordingly, efforts of Tibetan biodiversity conservation should include conclusions from p...