Markus Peintinger

RAPD variation among and within small and large populations of the rare clonal plant Ranunculus reptans (Ranunculaceae)

In the pre-alpine region of Europe numbers and sizes of populations of the clonal lake shore plant Ranunculus reptans have declined because of the regulation of lake water levels. We investigated genetic variation among and within 17 populations of different size (cover 1-10 000 m) in R. reptans with RAPD (random amplified polymorphic DNA) profiles. We sampled 127 rosettes in 14 populations at Lake Constance and three populations at or near Lake Como. There was significant genetic variation between plants from the two lake regions (5.9%, analysis of molecular variance [AMOVA], P < 0.001), among populations within lake regions (20.4%, P < 0.001), and within populations (73.7%, P < 0.001). Under the assumptions of Wrights island model the variation among populations corresponds to a gene flow of N(e)m = 0.70. Within the 14 Lake Constance populations we detected significant genetic variation among subpopulations separated by only a few metres (4.0% of the within-population variation; P < 0.05). Molecular variance was 24% smaller in small populations covering <100 m area than in larger ones (P < 0.03), indicating that samples from large populations were genetically more variable than samples representing comparable areas of smaller populations. We conclude that gene flow among populations is very limited and that genetic drift has caused reduced genetic variability of smaller populations. Conservation of genetic variability in R. reptans requires persistence of large and also of small populations (because of population differentiation), and it could be enhanced by increasing the size of small populations (to counter genetic drift).

Nutrient enrichment in calcareous fens: effects on plant species and community structure

Summary Calcareous fen meadows of low productivity belong to the most species-rich plant communities in central Europe. However, the deterioration of habitat quality by nutrient enrichment might threaten their high species diversity. To assess the potential impact of increased nutrient supply, we performed a two-year field experiment at 18 wetland sites in north-eastern Switzerland. We simulated atmospheric nitrogen deposition by adding a nitrogen fertilizer (N) and the influx of a combination of nutrients by adding a nutrient mixture (NPK), containing phosphorus and potassium as well as nitrogen. We recorded responses of the plant community, of four taxonomic-functional groups, and of transplanted individuals of a habitat specialist, Succisa pratensis , and a generalist, Filipendula ulmaria . The addition of nitrogen increased aboveground community biomass by 32% and full fertilization with NPK increased it by 70% these effects were independent of the initial productivity at the sites. Neither total species richness nor the number of specialist species was significantly affected after two years of nutrient application. However, the number of generalist species increased after the addition of NPK. Changes in the abundance of the four taxonomic-functional groups and of single species suggested that species composition and richness would change over longer periods of eutrophication. S. pratensis produced less biomass, both above- and belowground, when fertilized; in the longer run, it will probably be edged out by competition. F. ulmaria , on the other hand, increased the ratio between shoot and root biomass, grew taller and could thus keep pace with neighbouring plants. These results demonstrate that both atmospheric nitrogen deposition and the influx of a mixture of nutrients can drastically change the characteristics of fen meadows. To maintain the typical species composition of these wetlands and their rare species, all influences resulting in eutrophication should be minimized. Kalkflachmoore mit geringer Produktivitat gehoren zu den artenreichsten Pflanzengesellschaften in Mitteleuropa. Eine Beeintrachtigung der Habitatqualitat durch Nahrstoffeintrag kann aber ihre Artenvielfalt gefahrden. Wir fuhrten einen zweijahrigen Feldversuch in 18 Mooren der Nordostschweiz durch, um potentielle Auswirkungen eines erhohten Nahrstoff-Angebots zu erfassen. Wir simulierten einerseits einen atmospharischen Stickstoffeintrag durch Zugabe eines Stickstoff-Dungers (N), andererseits den Eintrag von verschiedenen Nahrstoffen aus umliegendem Landwirtschaftsland durch Zugabe einer Nahrstoffmischung (NPK), die neben Stickstoff auch Phosphor und Kalium enthielt. Wir erfassten die Reaktionen der Pflanzengemeinschaft und von vier taxonomisch-funktionellen Gruppen. Zusatzlich pruften wir, wie transplantierte Individuen eines Habitatspezialisten, Succisa pratensis , und eines Generalisten, Filipendula ulmaria , bei den verschiedenen Nahrstoffbehandlungen wuchsen. Die Zugabe von Stickstoff erhohte die oberirdische Biomasse der Pflanzengemeinschaft um 32%, diejenige der Nahrstoffmischung gar um 70%. Die Zunahme der Biomasse war unabhangig von der ursprunglichen Produktivitat des Standorts. Weder die totale Artenzahl noch die Anzahl der Habitatspezialisten veranderten sich nach zwei Jahren der Nahrstoffzugabe signifikant, hingegen stieg die Zahl der Generalisten nach Dungung mit NPK. Veranderungen in der Haufigkeit der vier taxonomisch-funktionellen Gruppen sowie von einzelnen Arten lassen darauf schliessen, dass sich durch die Eutrophierung die Artenzusammensetzung und -zahl langfristig verandern wird. Succisa pratensis produzierte unter Dungereinfluss sowohl ober- wie unterirdisch weniger Biomasse, so dass die Art langfristig vermutlich verdrangt wird. Filipendula ulmaria andererseits vergrosserte das Verhaltnis von ober- zu unterirdischer Biomasse, wuchs hoher und konnte so mit den Nachbarpflanzen mithalten. Diese Resultate zeigen, dass sowohl der atmospharische Stickstoffeintrag allein wie auch der Eintrag von verschiedenen Nahrstoffen die Charakteristik von Kalkflachmooren drastisch verandern kann. Um die typische Artenzusammensetzung dieser Feuchtwiesen und ihre seltenen Arten zu erhalten, mussen Eutrophierungseinflusse so gering wie moglich gehalten werden.

Species-area relationships and nestedness of four taxonomic groups in fragmented wetlands

Abstract Habitat fragmentation of semi-natural habitats is a serious problem in nature conservation because it leads to a decrease in habitat area and an increase of the isolation of habitat islands. In this paper, we examined the effects of habitat fragmentation on species richness and assemblages of four taxonomic groups. First, we used species-area relationships to assess the effect of habitat area on species richness per habitat island. Second, cumulative species-area curves were used to assess the question whether large habitat islands contain more species than several small islands of the same total area. Third, we examined to what extent species assemblages of species-poor habitat islands are nested subsets of those of species-rich ones. We analysed presence-absence data of vascular plants and bryophytes in 36, and of day-active butterflies and grasshoppers in a subset of 23 habitat islands (montane calcareous fens). The species-area relationship of each group was positive but was highly significant only for vascular plants. The slopes of the relationship on the log-log-scale were rather low (z-values: 0.06–0.11). The cumulative species-area curves of all groups showed that a set of small habitat islands contained more species than a set of a few large habitat islands with the same total area. The results of our nestedness ana-lyses depended on the underlying null models of the test statistics. Applying the method of Wright & Reeves (1992), all groups were significantly nested within the archipelago of habitat islands. Yet, using the method of Brualdi & Sanderson (1999), none of the groups showed non-random patterns. Our study showed that species richness increased with the area of habitat islands, but overlap among them was so low that even small habitat islands contributed to overall species richness. Therefore, a mosaic of several wetland islands, including small ones, is necessary to maintain species diversity at the landscape level. Die Fragmentierung naturnaher Habitate ist ein Problem im Naturschutz, weil sie einerseits eine Verkleinerung der Gesamtflache und andererseits die Isolation der entstehenden Habitatsinseln bewirkt. In diesem Artikel untersuchen wir die Effekte der Fragmentierung von Feuchtgebieten auf die Anzahl und Zusammensetzung der Arten von vier taxonomischen Gruppen. Erstens beschreiben wir den Effekt der Habitatsgrose auf die Artenzahl pro Habitatsinsel. Zweitens konstruieren wir kumulative Artenzahl-Areal-Kurven, um zu entscheiden, ob mehrere kleine Habitatsinseln mehr oder weniger Arten enthalten als wenige grose Habitatsinseln mit der gleichen Gesamtflache. Drittens gehen wir der Frage nach, in welchem Ausmas artenarme Habitatsinseln nur eine Teilmenge aus der Menge an Arten von artenreichen Inseln enthalten (‘Nestedness’-Frage). Wir analysierten Prasenz-Absenz-Daten von Gefaspflanzen und Moosen in 36 bzw. von Schmetterlingen und Heuschrecken in 23 montanen Kalkflachmooren. Die vier Gruppen zeigten alle eine positive Artenzahl-Areal-Beziehung, die aber nur bei den Gefaspflanzen hoch signifikant war. Die Steigung der Artenzahl-Areal-Beziehungen in doppelt-logarithmischer Darstellung war jedoch bei allen Gruppen relativ klein (z-Werte: 0,06–0,11). Die kumulativen Artenzahl-Areal-Kurven zeigten fur alle Gruppen, dass mehrere kleine Habitatsinseln mehr Arten enthielten als wenige grose Inseln mit der gleichen Gesamtflache. Die Resultate der Nestedness-Analyse hingen vom verwendeten Nullmodell fur die Teststatistik ab. Wurde die Methode von Wright & Reeves (1992) verwendet, so konnten bei allen Gruppen signifikante Nestedness festgestellt werden. Wurde hingegen die Methode von Brualdi & Sanderson (1999) verwendet, konnten bei keiner Gruppe signifikante Muster gefunden werden. Unsere Untersuchungen zeigten, dass zwar die Artenzahlen mit der Grose der Habitatsinseln zunahmen, dass aber auch selbst kleine Inseln wesentlich zur Gesamtartenzahl beitrugen. Ein Mosaik aus grosen und kleinen Habitatsinseln ist deshalb notig, um die Artenvielfalt auf Landschaftsniveau zu erhalten.

Restoration of montane fen meadows by mowing remains possible after 4–35 years of abandonment

Billeter R., Peintinger M. and Diemer M. 2007. Restoration of montane fen meadows by mowing remains possible after 4–35 years of abandonment. Bot. Helv. 117: 1 – 13.The abandonment of management in Swiss fen meadows has reduced their plant species diversity and the fitness of some typical fen species. We examined whether the resumption of mowing can reverse these effects, and if so, which mechanisms are responsible for community change; we also tested whether restoration success depends on the duration since abandonment. Experimental mowing was applied to 15 montane fen meadows of NE Switzerland that had been abandoned for 4–35 years. After two years of mowing, plant species richness was 11% higher in mown plots (2 m2) than in fallow plots, approaching levels of neighbouring continuously managed fen meadows. In particular, experimental mowing significantly increased the number of fen indicator species (+15%) as well as herbs and woody species (seedlings and saplings), while grass, sedge and rush species richness was not affected. Mowing had little effect on aboveground biomass, but strongly reduced litter mass (−50%) and canopy height (−20%). Seedling densities of two common species showed opposite responses to mowing: they increased in Carex davalliana and decreased in Succisa pratensis, approaching values of continuously mown fen meadows. Duration since abandonment had no significant effect on any of the variables. Our results demonstrate a rapid recovery of montane fen plant communities irrespective of the duration since abandonment (up to 35 years). We conclude that the restoration of pre-fallow plant community composition is likely to be successful if site conditions (hydrology, nutrient status) remain intact and if common habitat specialists are still present in the vegetation and/or seed bank.

Biological flora of Central Europe: Ranunculus reptans L.

Summary Ranunculus reptans is a stoloniferous perennial herb of inundated lake shores. It is native to Central Europe, where it has become a rare and endangered species. This article reviews the morphology and taxonomic status, the distribution, ecology, population biology and genetics of this taxon.

Ploidy level, genetic diversity, and differentiation in two closely related mosses, Scorpidium cossonii and S. revolvens (Calliergonaceae)

Abstract As ploidy level and mating system can affect genetic diversity and differentiation, we conducted population genetic analyses of two closely related mosses, Scorpidium cossonii (Schimp.) Hedenäs, and S. revolvens (Sw. ex Anonymo) Rubers which differ in ploidy level and sexual system. We collected 315 specimens in total from five populations of S. cossonii and four populations of S. revolvens in the Swiss Alps. Ploidy level, genetic diversity within populations, and genetic differentiation between populations and species were estimated using nine microsatellite markers. In each S. cossonii sample, each locus bore only one allele, while in S. revolvens, seven out of the nine loci were fixed or nearly fixed for two alleles per locus per individual. These findings are consistent with a gametophytic haploid S. cossonii and allodiploid S. revolvens. The haploid and dioicous S. cossonii was genetically more diverse than the (allo)diploid and monoicous S. revolvens. Differences in genetic diversity between the two species may be explained by different mating systems, different population sizes, and different population histories. Genetic differentiation among populations of S. cossonii was higher than among those of S. revolvens. The low genetic differentiation among populations of the monoicous species was not unexpected, since monoicous species frequently produce sporophytes, long-distance spore dispersal is more likely and leads to low differentiation.

Characterization of nuclear microsatellite loci in the calcareous fen specialist Scorpidium cossonii (Calliergonaceae)

PREMISE OF THE STUDY Nuclear microsatellite markers were developed in the fen specialist moss, Scorpidium cossonii, to study genetic diversity and genetic structure of this species in relation to land-use types, habitat fragmentation, and habitat conservation measures. METHODS AND RESULTS The polymorphisms of 14 microsatellite markers were characterized. All primers were tested on 140 gametophytes collected from four populations in Switzerland. The primers amplified di- and trinucleotide repeats with three to 26 alleles per locus. The primers worked also in the two other species of the genus: 14 and 12 primers successfully amplified in S. revolvens and S. scorpioides, respectively. CONCLUSIONS In future studies, our primers have the potential to provide valuable information on genetic diversity, genetic structure, and on historical and recent gene flow in S. cossonii; they should also enable related research in other Scorpidium species.

Sind Naturschutzgebiete ein wirksames Instrument im Artenschutz? Bilanz nach 26 Jahren in zwei südwestdeutschen Naturschutzgebieten

During 26 years the number of species and territories of breeding birds was counted annually in two nature reserves in Southwest Germany. The trends for both factors are negative. An increase of human activities is seen as the main reason for the decline.