Search

As one of the most prominent topographical features on Earth, the Qinghai-Tibetan plateau (QTP) underwent a long and complex history of the QTP uplift from the collision of the Indian and the Eurasian plates to the present. At its southern and southeastern margins, it is flanked by the most significant hotspots of organismic diversity of the northern hemisphere (including birds), the Sino-Himalayan mountain forests. In contrast, the central plateau region itself harbours species-poor communities but also a good number of endemics that presumably evolved from rather ancient (pre-Pleistocene) phylogenetic lineage splits. We discuss the evolutionary history of QTP passerines from a twofold perspective including examples from our own research. First, we provide an overview of those alpine QTP endemics that represent late Miocene and Pliocene lineage splits, i.e. early colonisations to the central alpine QTP region. As an example, true rosefinches (genus Carpodacus) presumably evolved from a forested eastern QTP centre of origin and colonised the (semi-)open plateau habitats several times independently. Second, we discuss younger speciation events corresponding to phylogeographic east-west divides along the southern QTP margin. A multidisciplinary approach combining genetic, bioacoustic and morphological markers shed new light on the phylogenetic relationships of Pnoepyga wren babblers and on the intraspecific subdivision of the Buff-barred Warbler ( Phylloscopus pulcher). [ABSTRACT FROM AUTHOR]

Grasslands are very important regionally and globally because they store large amounts of carbon (C) and nitrogen (N) and provide food for grazing animals. Intensive degradation of alpine grasslands in recent decades has mainly impacted the upper root-mat/soil horizon, with severe consequences for nutrient uptake in these nutrient-limited ecosystems. We used N labeling to identify the role of individual soil layers for N-uptake by Kobresia pygmaea-the dominating plant in the degraded Tibetan pasture ecosystems. We hypothesized a very efficient N-uptake corresponding mainly to the vertical distribution of living roots (topsoil > subsoil). We assume that K. pygmaea develops a very dense root-mat, which has to be maintained by small aboveground biomass, to enable this efficient N-uptake. Consequently, a higher N-investment into roots compared to shoots was hypothesized. The N recovery in whole plants (~70%) indicated very efficient N-uptake from the upper injection depths (0-5 cm). The highest N amounts were recovered in root biomass, whereby N recovery in roots strongly decreased with depth. In contrast, N recovery in shoots was generally low (~18%) and independent of the N injection depth. This clearly shows that the low N demand of Kobresia shoots can be easily covered by N-uptake from any depth. Less living root biomass in lower versus upper soil was compensated by a higher specific activity of roots for N-uptake. The N allocation into roots was on average 1.7 times higher than that into shoots, which agreed well with the very high R/S ratio. Increasing root biomass is an efficient strategy of K. pygmaea to compete for belowground resources at depths and periods with available resources. This implies high C-costs to maintain root biomass (~6.0 kg DM m), which must be covered by a very low amount of photosynthetically active shoots (0.3 kg DM m). It also suggests that Kobresia grasslands react extremely sensitively toward changes in climate and management that disrupt this above-/belowground trade-off mechanism. [ABSTRACT FROM AUTHOR]

The Chinese grouse Tetrastes sewerzowi is restricted to small mountain areas on the southeastern edge of Qinghai-Tibet plateau. Recent evidence indicates that the global climate has undergone rapid change. To assess the potential effects of climate change on Chinese grouse, we applied a maximum-entropy modeling (MaxEnt) method to predict the current and future distributions of this species for three time periods: 2020, 2050 and 2080 in two greenhouse-gas emissions scenarios (A2a and B2a), which assume a medium and a lower increase in CO2 emissions, respectively. Our modeling revealed that: 1) the size of suitable areas for grouse will decline over time, especially in emissions scenario A2a; 2) range shifts will happen at both latitudinal (northward shift) and elevational direction (upward). In addition, habitat expansion will be limited relative to loss, especially in the more distant future. Although the size of suitable area will not change greatly in the near future (e.g. 2020 and 2050), as predicted in the emissions scenario A2a in 2020, habitat will become more fragmented. Therefore, we suggest that the habitat fragmentation be considered with range shifts calculation while assessing the climate change threats. To cope with the ongoing climate change, either the protected area of the existing reserves should be expanded or new reserves should be established to accommodate range shifts. Reforestation and gouse population monitoring should also be conducted in the reserves to track response of grouse to climate change. [ABSTRACT FROM AUTHOR]