Showing papers by "Bernhard Schmid published in 1996"

Long-term persistence in a changing climate: DNA analysis suggests very old ages of clones of alpine Carex curvula.

Abstract: Carex curvula is a very slow-growing rhizomatous sedge that forms extensive stands in the European an alpine belt. The recruitment of sexual progeny is extremely rare and propagation occurs predominantly through clonal growth. The randomly amplified polymorphic DNA (RAPD) technique was used to analyse clonal structure in a small patch (2.0x0.4 m sampling transect plus some additional samples) of a high-alpine population of the species. Amplification of the DNA of 116 tiller samples from the patch with eight ten-base primers yielded a total of 95 bands, of which 73 were polymorphic. Based on the RAPD amplification profiles a total of 15 multilocus genotypes (putative clones) were identified. Due to the high number of polymorphic loci the number of genetic markers delineating individual clones was high (range: 16–39 markers) which suggests that our estimates of clonal diversity are precise. More than half of the sampled tillers were identified as belonging to a single clone which formed a relatively homogeneous disc intermingling with other clones only at its margin. Based on the maximum diameter of this large clone of more than 7000 tillers and estimates of annual expansion growth of rhizomes (0.4 mm year-1), the age of the clone was calculated to be around 2000 years. This demonstrates that clones of C. curvula may persist on a single spot over long periods with quite diverse alpine climates ranging from rather mild periods in the Middle Ages to cool periods during the so called “little ice age” in the last century. Our results suggest caution with plant migration scenarios based on shifting isotherms where late-successional clonal species, which dominate the alpine vegetation all over the world, are concerned.

Variation in species richness of plants and diverse groups of invertebrates in three calcareous grasslands of the Swiss Jura mountains

Abstract: Species richness and abundance of vascular plants and several groups of invertebrates (spiders, oribatid mites, diplopods, grasshoppers and bush crickets, ground beetles, butterflies and terrestrial gastropods) were recorded in three calcareous grasslands (Nenzlingen, Movelier and Vicques) in the northwestern Swiss Jura mountains. Species richness varied both between taxonomical groups and between sites (species richness ranges: 96-116 vascular plants, 60-66 spiders, 18 oribatid mites at each site, 1-7 diplopods, 10-16 grasshoppers and bush crickets, 19-21 ground beetles, 32-46 butterflies and 15-21 terrestrial gastropods). Species overlap (number of species that occured at all sites) was relatively large in terrestrial gastropods (59,1%), butterflies (56,5%), vascular plants (53,8%) and gasshoppers (47,1%), but relatively low in oribatid mites (32,3%), spiders (25,0%), ground beetles (18,4%) and diplopods (12,5%). Diversity expressed by the Shannon-Wiener index (H') was compared for five groups of invertebrates. Diversity was largest in spiders and ground beetles and lowest in terrestrial gastropods. Different taxonomical groups had their maximum diversity at different sites: each grassland had the highest diversity in a least one groupe. The three sites also varied in the abundance of different invertebrate groups. Most groups had the highest densities in Nenzlingen and the lowest densities in Vicques. All three sites contained a high proportion of species listed in the Red Data Book of Switzerland with values averaging 49,5% in grasshoppers and buch crickets, 28,9% in butterflies, 18,9% in vascular plants, 11,2% in terrestrial gastropods, and 6,7% in ground beetles. One spieder species (Oxyptila pullata) and two mite species (Epilohmannia cylindrica minima and Pergalumna myrmophila) were recorded for the first time in Switzerland.