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Recent treeline dynamics are similar between dry and mesic areas of Nepal, central Himalaya

Journal of Plant Ecology 2015年第4期8卷 347-358页

作者： Krishna B.Shrestha Annika Hofgaard vigdis vandvik Department of Biology University of BergenPO Box 7803NO-5020BergenNorway UiB Global University of BergenJekteviksbakken 31PO Box 7800NO-5020BergenNorway Norwegian Institute for Nature Research PO Box 5685 SluppenNO-7485TrondheimNorway

Aims We investigated the treeline dynamics of two environmentally con-trasting areas in the Nepalese Himalaya to address the following questions:(i)Does the timing of establishment of the current tree-line differ between the two study areas,and can area-specific tree-line developments be identified?(ii)Do recruitment patterns and height growth indicate recent climate-driven treeline advance,fol-lowing the general prediction for the central Himalayan region,in the two study areas?Methods a dry-climate treeline dominated by Pinus wallichiana and a mesic-climate treeline with Abies spectabilis were selected for study.In each area,we sampled the size and age structure of the study spe-cies along three elevational transects(20-m wide)from the forest line to the tree species line crossing the treeline.We also sampled treeline trees from within and outside transects to reconstruct past treeline establishment dynamics.Important Findings Despite differences in moisture regimes,tree species and recent climate trends,our two study areas showed very similar treeline dynamics over the past six decades.In both areas,the recruitment of treeline trees indicates stationary treelines over the past six decades with the current treelines being dominated by trees that were established around 1990.the mesic area has experienced an overall climatic warming trend,and the stationary Abies treeline is hypothesized to be regulated by non-climatic factors,notably grazing.the dry area has not experienced warming but increased climatic variability and some very cool summers in the recent dec-ades may explain the stationary to weakly receding Pinus treeline,which appears more climatically controlled with decreased recruit-ment over the past decades and decreased growth towards higher elevations.In both areas,there is a potential for treeline advance,depending on future land use and climate change.our results highlight the importance of conducting treeline ecotone analyses for several sites or areas,and considering both climatic and non-climati

关键词： Abies spectabilis Himalaya Pinus wallichiana slope aspect treeline ecotone dynamics

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Temperature and precipitation,but not geographic distance,explain genetic relatedness among populations in the perennial grass Festuca rubra

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Journal of Plant Ecology 2019年第4期12卷 730-741页

作者： MariaŠurinová Věroslava Hadincová vigdis vandvik Zuzana Münzbergová Department of Botany Faculty of ScienceCharles UniversityPragueCzech Republic Institute of Botany Academy of Sciences of the Czech RepublicPrůhoniceCzech Republic Department of Biology University of BergenBergenNorway Bjerknes Centre for Climate Research BergenNorway

Aims Knowledge of genetic structure of natural populations and its determinants may provide key insights into the ability of species to adapt to novel environments.In many genetic studies,the effects of climate could not be disentangled from the effects of geographic proximity.We aimed to understand the effects of temperature and moisture on genetic diversity of populations and separate these effects from the effects of geographic distance.We also wanted to explore the patterns of distribution of genetic diversity in the system and assess the degree of clonality within the populations.We also checked for possible genome size variation in the system.Methods We studied genetic variation within and among 12 populations of the dominant grass Festuca rubra distributed across a unique regional-scale climatic grid in western Norway,Europe and explored the importance of temperature,precipitation and geo-graphic distance for the observed patterns.We also explored the distribution of genetic diversity within and among popula-tions,identified population differentiation and estimated degree of clonality.The analyses used microsatellites as the genetic marker.The analyses were supplemented by flow cytometry of all the material.Important Findings All the material corresponds to hexaploid cytotype,indicating that ploidy variation does not play any role in the system.The results indicate that temperature and precipitation were better predictors of genetic relatedness of the populations than geographic distance,suggesting that temperature and precipitation may be important determinants of population differentiation.In addition,precipitation,alone and in interaction with temperature,strongly affected population genotypic diversity suggesting increased clonality towards the coldest and especially the coldest wettest climates.At the same time,individuals from the coldest and wettest climates also had the high-est individual genetic diversity,suggesting that only the most hetero-zygous individuals survive under these harsh climates.M

关键词： AMOVA hexaploid isolation by distance isolation by environment microsatellites Poaceae fuzzy clustering

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