Andreas Erhardt

University of Basel | UNIBAS · Department of Environmental Sciences

The importance of wild bees for crop pollination is well established, but less is known about which species contribute to service delivery to inform agricultural management, monitoring and conservation. Using sites in Great Britain as a case study, we use a novel qualitative approach combining ecological information and field survey data to establi...

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The Northern Bald Ibis (NBI) Geronticus eremita , is an ‘Endangered’ bird species of which only very few wild breeding colonies have survived along the Atlantic coast of south-west Morocco. This paper analyses ecological conditions of the 72 breeding sites of the NBI that have been known since 1900 in Morocco. Characterisation of breeding sites is...

Increasing light emissions caused by human activities have been recognized as a major threat for nocturnal animals. In Switzerland, the European Nightjar is a rare bird, decreasing in numbers since the 1970s, and is therefore highly threatened. The last breeding population occurs in the canton Valais. Initial expert-based conservation measures on f...

Reproductive success of Dianthus armeria is guaranteed by 10 pollination by insects or self-fertilisation. In an island, urban and another 11 natural habitat, different flower experiments at two populations of the 12 caryophyllean Dianthus armeria were done. In comparing treatments, there 13 were strong indications, that Dianthus armeria is an adap...

Quantifying the relative contribution of multiple isolation barriers to gene flow between recently diverged species is essential for understanding speciation processes. In parapatric populations, local adaptation is thought to be a major contributor to the evolution of reproductive isolation. However, extrinsic postzygotic barriers assessed in reci...

Recent studies with diverse taxa have shown that parents can utilize their experience of the environment to adapt their offspring’s phenotype to the same environmental conditions. Thus, offspring would then perform best under environmental conditions experienced by their parents due to transgenerational phenotypic plasticity. Such an effect has bee...

Recent studies with diverse taxa have shown that parents can utilize their experience of the environment to adapt their offspring’s phenotype to the same environmental conditions. Thus, offspring would then perform best under environmental conditions experienced by their parents due to transgenerational phenotypic plasticity. Such an effect has bee...

Twenty years ago, scientists began to recognize that parental effects are one of the most important influences on progeny phenotype. Consequently, it was postulated that herbivorous insects could produce progeny that are acclimatized to the host plant experienced by the parents to improve progeny fitness, because host plants vary greatly in quality...

The genus Fragaria (Rosaceae) contains 24 species, including hybrid species such as the garden strawberry (Fragaria × ananassa Duch.). Natural hybridization between Fragaria species has repeatedly been reported, and studies on the hybridization potential between F. × ananassa and its wild relatives have become increasingly important with the outloo...

The genus Fragaria (Rosaceae) contains 24 plant species, including hybrid species such as the octoploid garden strawberry (F. × ananassa). Natural hybridization between Fragaria species has repeatedly been reported, and the potential future cultivation of genetically modified strawberries has made the study of hybridization potential between F. × a...

Nitrogen is a key nutrient for fitness in insects, but host plant defence can deter herbivores from acquiring it. Therefore, coping with host plant defence is a predominant issue for herbivores. Butterflies have the ability to compensate for a nitrogen-poor diet both as herbivorous larvae and as nectar-feeding adults. We examined whether silica (S)...

The relative importance of sexual and clonal reproduction for population growth in clonal plants is highly variable. Clonal reproduction is often more important than sexual reproduction but there is considerable interspecific variation and the importance of the two reproductive modes can change with environmental conditions. We carried out a demogr...

After over 30 years of research, it was recently shown that nectar amino acids increase female butterfly fecundity. However, little attention has been paid to the effect of nectar amino acids on male butterfly reproduction. Here, we show that larval food conditions (nitrogen-rich vs. nitrogen-poor host plants) and adult diet quality (nectar with or...

Butterfly-pollinated flowers offer nectar with higher amino acid concentrations than most flowers pollinated by other animals, and female butterflies of some species prefer to consume amino acid-rich nectar. However, for over 30 years, there has been an ongoing discussion about whether nectar amino acids benefit butterfly fitness. A clear positive...

he principal components of floral nectar are water and the sugars sucrose, fructose and glucose. Several studies have shown the importance of nectar sugars for female butterfly fecundity, whereas to date little attention has been paid to the effect of nectar sugars on male butterfly reproduction. Clear evidence for an effect of nectar sugars on mal...

Short growing seasons, low temperatures, and frequent strong wind classify high mountains as adverse environments, in which pollinator abundance and activity are reduced. In such environments, plants growing in dense stands comprising several species and thus exhibiting larger and more diverse flower displays may profit by attracting more visits fr...

Plants flowering together may influence each other's pollination and fecundity over a range of physical distances. Their effects on one another can be competitive, neutral, or facilitative. We manipulated the floral neighborhood of the high-alpine cushion plant Eritrichium nanum in the Swiss Alps and measured the effects of co-flowering neighbors o...

Typological schemes that describe putative floral adaptations for pollinators have played a central role in pollination biology. In 1882 the prominent German botanist and Darwinist Hermann Müller commented critically on a precursor of modern versions of such “pollination syndromes” that had been developed by his Italian colleague Federico Delpino....

Experimental crosses between the diploid woodland strawberry (Fragaria vesca L.) and the octoploid garden strawberry (F. × ananassa Duch.) can lead to the formation of viable hybrids. However, the extent of such hybrid formation under natural conditions is unknown, but is of fundamental interest and importance in the light of the potential future c...

Darwin's meticulous observations on the function of floral shape led to his famous prediction of a long-tongued pollinator, which he believed to be the evolutionary trigger for the long-spurred flowers of the Madagascar star orchid. Although tubular flowers are common, long tubes or spurs are an exception, suggesting that selection maintaining shor...

Cyanogenesis is a widespread chemical defence mechanism in plants against herbivory. However, some specialised herbivores overcome this protection by different behavioural or metabolic mechanisms. In the present study, we investigated the effect of presence or absence of cyanogenic glycosides in birdsfoot trefoil (Lotus corniculatus, Fabaceae) on o...

This paper describes the pollinators, scent and nectar composition of the edelweiss (Leontopodium alpinum). In contrast to former statements in the literature, the flowers of this famous plant are frequently visited by various insects in 29 familieS. However, in the two populations of L. Alpinum investigated here, flies (Muscidae) were the most fre...

. 1Butterflies of Battus philenor were tested for their preferences for nectar sugars and amino acids in an outdoor cage experiment.2The butterflies clearly preferred both sucrose and fructose over glucose. They also preferred sucrose over fructose.3No other preferences were found to be statistically significant, although male butterflies tended to...

Alpine grasslands in the Southern Carpathian Mts, Romania, harbour an extraordinarily high diversity of plants and invertebrates, including Carpathic endemics. In the past decades, intensive sheep grazing has caused a dramatic decrease in biodiversity and even led to eroded soils at many places in the Carpathians. Because of limited food resources,...

Recent changes in agriculture (intensification or abandonment) have resulted in a critical reduction of semi-natural grasslands in Eastern Europe. Subalpine semi-natural grasslands in Transylvania, Romania, harbour a high diversity of plants and invertebrates, including endemics, and are considered refugia for numerous threatened open-land species....

Without Abstract

Knowledge of pollination services provided by flower visitors is a prerequisite for understanding (co)evolutionary processes between plants and their pollinators, for evaluating the degree of specialization in the pollination system, and for assessing threats from a potential pollination crisis. This study examined pollination efficiency and visita...

Effects of elevated CO2 and nutrient availability on nectar production and onset of flowering in five different seed families (genotypes) of Epilobium angustifolium were investigated in a greenhouse experiment. Elevated CO2 significantly increased nectar production per day (+51%, p < 0.01), total sugar per flower (+41%, p < 0.05), amino acid concen...

Recent changes in agriculture (intensification or abandonment) have resulted in a critical reduction of steppe-like grasslands in Eastern Europe. These grasslands harbor an extraordinarily high diversity of plants and invertebrates, including endemics, and are considered refugia for numerous threatened open-land species. We examined species richnes...

Thirty years ago, researchers discovered that flowers pollinated by butterflies are consistently rich in nectar amino acids, and more recent findings have shown that butterflies prefer nectar with high amino acid content. These observations led to speculation that amino acids in nectar enhance butterfly fitness and that butterflies have acted as ag...

Thirty years ago, researchers discovered that flowers pollinated by butterflies are consistently rich in nectar amino acids, and more recent findings have shown that butterflies prefer nectar with high amino acid content. These observations led to speculation that amino acids in nectar enhance butterfly fitness and that butterflies have acted as ag...

Effects of elevated CO2 and P availability on plant growth of the legume Lotus corniculatus and consequences for the butterfly larvae of Polyommatus icarus feeding on L. corniculatus were investigated in screen-aided CO2 control chambers under natural conditions on a calcareous grassland in the Swiss Jura mountains. Elevated CO2 conditions and P fe...

It is generally assumed that butterflies, as is the case with many holometabolous insects, rely primarily on nutrients gathered by larval feeding for somatic maintenance and fecundity. These reserves can be supplemented by adult feeding and in some cases by nuptial gifts passed from the males to the females during mating. Recent findings indicate t...

The importance of nectar constituents, especially amino acids, for fecundity in butterflies has been controversial. This study examined the influence of Lantana camara nectar amino acids on various fecundity parameters, taking maternal lineage into consideration. Lasiommata megera L. butterflies were either fed a nectar mimic containing amino acids...

The effects of larval diet on the nutritional preferences of butterflies has rarely been examined. This study investigates whether alterations in the larval diet result in changes in adult preferences for nectar amino acids. Larvae of Coenonympha pamphilus were raised on fertilized or unfertilized Festuca rubra, grown under ambient (350ppm) or elev...

The objective of this study was to determine effects of elevated CO2 and soil nutrient availability on growth and plant tissue quality in four grass species, Agrostis stolonifera, Anthoxanthum odoratum, Festuca rubra and Poa pratensis, native in Western European calcareous grassland. Plants were grown for 65 days in the greenhouse in pots with untr...

The objective of this study was to determine how increasing atmospheric CO2 change plant tissue quality in four native grassland grass species (Agrostis stolonifera, Anthoxanthum odoratum, Festuca rubra, Poa pratensis) which are all larval food-plants of Coenonympha pamphilus (Lepidoptera, Satyridae). We assessed the effect of these changes on the...

Abstract This study tested Inachis io L. butterflies' preference for nectar amino acids using a dilution series (100, 75, 50, 25 and 0%) of the amino acid concentration of Lantana camara to determine how sensitive the insects are to low concentrations of amino acids, such as those found in the flowers of many plant species. Female butterflies clear...

 Flower development, pollination and breeding system of the high alpine cushion plant, Eritrichium nanum (Boraginaceae), were investigated in nine populations from the European Alps at altitudes of 2700 m–3200 m. Peak flowering period lasts longer than a month, from mid-June to the end of July. In contrast to statements in the literature that flowe...

Habitat destruction and degradation are the major causes for the decline of the endangered grass-feeding flightless beetle Dorcadion fuliginator in Central Europe. We examined habitat characteristics at 19 localities which still support abundant D. fuliginator populations in the southern part of the Upper Rhine valley (border region of Switzerland,...

Abstract 1. Plant growth and chemical defence compounds in four Lotus corniculatus genotypes exposed to factorial combinations of ambient and elevated carbon dioxide, and herbivory by caterpillars of Polyommatus icarus were measured to test the predictions of the carbon/nutrient balance hypothesis. 2. Shoot and root biomass, allocation to shoots ve...

Elevated atmospheric CO 2 can affect plant - insect herbivore interactions, primarily due to changes in leaf nutritional quality. However, current experimental evidence is predominantly based on greenhouse studies, and there is a paucity of data gained in natural plant communities growing under natural climatic conditions. We investigated the devel...

1. Four Lotus corniculatus genotypes differing in cyanoglycoside and condensed tannin concentrations were grown in either low (350 ppm) or high (700 ppm) atmospheric CO2 environments. Larval performance, consumption and conversion efficiency of Polyommatus icarus feeding on this plant material were measured. 2. Plants grown under elevated CO2 conta...

We examined visiting patterns of pollinators of Betonica officinalis L. (Lamiaceae) in experimentally fragmented calcareous grasslands and corresponding control plots at two study sites (Movelier and Nenzlingen) in the north-western Swiss Jura mountains. Fragments (1.5×1.5 m) were isolated by a 5-m wide strip of frequently mown vegetation while the...

Steppe habitats in Transylvania are rich in rare and endemic Lepidoptera species. Because of their island-like distribution they should be carefully studied and mapped in order to develop efficient conservation practices. Căianu Mic harbors steppe habitats similar to those in the Suatu nature reserve but they have not been investigated until now. W...

1. Field observations in the Swiss Jura mountains showed that males and females of the bivoltine Adonis Blue butterfly Lysandra bellargus Rott. differed significantly in their flower visitation patterns. 2. In both generations, females visited a broader range of available nectar plants than did males. The specific flower visitation patterns of male...

The fragmentation of natural habitats is generally considered to be a major threat to biodiversity. We investigated short-term responses of vascular plants (grasses and forbs) and four groups of invertebrates (ants, butterflies, grasshoppers and gastropods) to experimental fragmentation of calcareous grassland in the north-western Jura mountains, S...

Results from pot and microcosm studies in the greenhouse have shown that plant growth and foliar chemistry is altered by the presence and species composition of arbuscular mycorrhizal fungi (AMF). The growth and survival of herbivores which feed on plants could, as a consequence, also be affected by these mutualistic soil fungi. Consequently, inter...

Because of changes in land use, the quantity of extensively grazed or mown calcareous grasslands and their successional stages have drastically declined over the last few decades in Central Europe. Old fallow land has decreased most. It is often afforested or reconverted into extensively cultivated grassland because extensive cultivation is believe...

The preferences for nectar amino acids, urea and ammonium ions of peacock butterflies, Inachis io, were tested experimentally. Females clearly preferred a mimic of Lantana camara nectar containing amino acids to an otherwise similar plain sugar solution, whereas males did not discriminate between these test solutions. Neither males nor females disc...

Effects of elevated CO2 on flowering phenology and nectar production were investigated in Trifolium pratense, Lotus corniculatus, Scabiosa columbaria, Centaurea jacea and Betonica officinalis, which are all important nectar plants for butterflies. In glasshouse experiments, juvenile plants were exposed to ambient (350 μl l−1) and elevated (660 μl l...

Effects of elevated CO2 on flowering phenology and nectar production were studied in five important nectar plants of calcareous grasslands, i.e. Lotus corniculatus, Trifolium pratense, Betonica officinalis, Scabiosa columbaria ia and Centaurea jacea. Glasshouse experiments showed that flowering probability was significantly enhanced in C. jacea. B....

Habitat suitability for larval and/or adult Mellicta athalia ssp. celadussa (Rott.) was examined in a variety of grassland types: traditionally cultivated hay meadows, different successional stages of abandoned grasslands and differently managed abandoned grasslands. Larval food-plants and caterpillars occurred almost exclusively in traditionally c...

1. Peacock butterflies, Inachis io, were tested experimentally for their preferences for nectar sugars. 2. In tests with different plain sugar solutions (25%, weight to total weight) the butterflies strongly preferred sucrose and fructose over glucose. They also preferred sucrose over fructose. 3. In tests with mixed sugar solutions the butterflies...

Extensiv genutzte Wiesen oder Magerwiesen sind artenreiche, durch menschliche Nutzung geschaffene Lebensräume. Sie sind durch Rodung und langjährige Bewirtschaftung von ursprünglich meist bewaldeten Flächen entstanden. Es werden verschiedene Typen von Extensivwiesen unterschieden: (1) Borstgras-Rasen (Nardion) auf kalkarmen Böden, (2) Kalk-Magerras...

Die jahrhundertlange Haustierhaltung führte allmählich zur Ausbildung von offenem Grünland, dessen natürliche Wiederbewaldung meist durch Weidehaltung verhindert wurde. Je nach Standort sind unterschiedliche Extensivweiden entstanden. Die zwei wichtigsten Typen sind (1) Borstgras-Magerrasen (Nardion) auf kalkarmen Böden in eher höheren Lagen und (2...

Die biologische Vielfalt oder Biodiversität umfasst die Mannigfaltigkeit und Variabilität der Lebewesen und der räumlichen und landschaftlichen Strukturen, in die sie eingebunden sind (Primack, 1995)2. Biodiversität kann auf drei Ebenen betrachtet werden. Grundlegend ist die Vielfalt der Arten von Viren, Bakterien, Pilzen, Pflanzen und Tieren. Eine...

Die Waldweide ist eine der ursprünglichsten landwirtschaftlichen Nutzungsformen (Ellenberg, 1996). Durch Verbiss des Viehs, durch Schlagen oder Abbrennen von Bäumen und Holzraubbau entstand über eine lange Zeitperiode die offene Feldflur. Bis ins letzte Jahrhundert wurden Haustiere in den Wald getrieben, wo sie Unterwuchs, Laub, junge Triebe und Fr...

Wenig intensiv genutzte Wiesen werden meist zweimal jährlich geschnitten und mässig mit Mist oder Gülle gedüngt. Wie die Magerwiesen ist auch dieser Wiesentyp durch traditionelle Bewirtschaftung entstanden. Da ursprünglich eher ein Mangel an Naturdünger (Mist und Gülle) bestand, wurden vor allem die besten Böden in Tallagen gedüngt. Wenig intensiv...

Grundlagen zur Beurteilung des Naturschutzwertes ausgewählter landwirtschaftlicher Nutzflächen. Kapitel pro Lebensraumtyp. Hier: nur Impressum + Inhaltsverzeichnis + Einleitung.

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...

Ich blicke aus dem Fenster, vor mir, einen Sportplatz umgebend, Weissbuchen, welche gerade ihre Blätter im ersten zarten Grün treiben. Davor ein Birnbaum, in voller Blüte. Ein durchaus alltäglicher Anblick zu dieser Jahreszeit und doch ergreifend beim verweilenden, absichtslosen Anschauen.

Many human activities, such as deforestation, urbanization, intensive agriculture, the building of roads and railways all reduce natural habitats to remnants of different size. In addition to the overall decrease in the area available for the organisms, the fragmentation of habitats leads to a division of existing populations into isolated subpopul...

Nectar secretion patterns, volume, sugar amount, sugar concentration and sucrose/hexose-ratios in Salvia pratensis varied considerably between flowers of different plants, both during the course of a single day as well as over the whole anthesis, which lasted for 4 days. In spite of this variation, the sucrose/hexose-ratio remained always sucrose-d...

The microdistribution of five butterfly species through their flying season was analyzed in a mosaic-like habitat, brought about by secondary succession In order to explain the patterns observed, activity patterns and the use and distribution of nectar sources were determined Emphasis was laid on the changing allocation of visits to flower species...

Pollination of the alpine herbDianthus glacialis was studied in a population in the Swiss Alps in 1991 and 1992. Only one insect species,Zygaena exulans (Lepidoptera), was observed to visit the flowers ofD. glacialis. Pollen loads onZ. exulans indicate that it is an effective pollinator ofD. glacialis. In 1991,Z. exulans frequently visited flowers...

Although there are indications that Lepidoptera had started to decrease early in the twentieth century (Entomologischer Verein Alpstein, 1989), they have declined throughout Europe most markedly during the past few decades. This decrease is so strong that it has been noticed not only by lepidopterists but even by lay-persons. According to red data...

Summary Preferences for nectar sugars and amino acids ofOrnithoptera priamus butterflies were tested experimentally. Both male and female butterflies clearly preferred a sucrose solution over a glucose solution of equal concentration (25%, weight to total weight) and equally a fructose solution over a glucose solution. A significant trend of males...

Pollination of Dianthus superbus was studied in a subalpine population in the Swiss Alps. The flowers were visited exclusively by migratory nocturnal hawkmoths Herse convolvuli in 1987, but in 1988 native noctuid moths were the most frequent flower visitors. The brightly coloured petals, calyx length and the strong sweet scent produced in the eveni...

The increase of the amino acid concentration over different time intervals in artificial nectar (i.e., a sucrose solution) due to pollen contamination was investigated in four Californian plant species (Aesculus californica, Amsinckia lunaris, Brodiaea pulchella, Carduus pycnocephalus), which are important nectar resources for a Californian colony...

Pollination ofDianthus gratianopolitanus was studied in a population of the Swiss Jura mountains. Pollinators of this plant species are reported here for the first time. The flowers were not only visited by butterflies as postulated in the literature, but also by diurnal hawkmoths (Macroglossum stellatarum) and by diurnal and nocturnal noctuid moth...

Dianthus silvester Wulf. is a widely distributed but not too common plant species which occurs in Central and South European mountain ranges (Hegi 1979). The morphology of the flower has been described already by Müller (1881). However, only scanty observations on pollinators have been reported so far. Müller (1881) observed the sphingid Macrogloss...

(1) In the subalpine region of Central Switzerland (Tavetsch Valley) studies were made of the day-active Lepidoptera faunas in different types of cultivated grassland, in various stages in the development of abandoned grassland and in woodlands (climax vegetation). (2) The results show a close correlation between bufferfly fauna and vegetation type...

Als Untersuchungsgebiete wurden ursprünglich alle in der Dissertation von Bischof (1980) untersuchten Täler, also Tavetsch, Urseren-Tal, Obergoms und Bedretto in Betracht gezogen. Die Wahl fiel auf das Tavetsch, weil dort die zu untersuchenden Vegetationstypen am grossflächigsten ausgebildet sind. Dies ist für die Untersuchung der Lepidopteren-Faun...

Die Lepidopterenfauna der verschiedenen Untersuchungsflächen wurde mit der Transsektmethode erfasst. Diese Methode besteht darin, dass ein Beobachter ruhig entlang einer bestimmten Transsektlinie schreitet und jeden Falter identifiziert und protokolliert, den er innerhalb einer Distanz von maximal etwa 5 m feststellt. So entsteht eine Artenliste mi...

Vor einer spezielleren Diskussion der vorliegenden Arbeit im Zusammenhang mit der Brachlandsituation möchte ich versuchen, ihre grundsätzliche Position im Umfeld ökologischer Forschung kurz zu skizzieren.

Naturschutz ist Menschenschutz; wie die Menschen mit der Natur umgehen, so pflegen sie auch den Umgang mit ihresgleichen (Portmann 1971, Eckholm 1980, Fromm 1976).

Für genaue Häufigkeitsbestimmungen der Imagines der verschiedenen Arten müsste deren ganze Phänologie sowie deren Schlüpf- und Absterberaten, respektive deren Lebensdauer berücksichtigt werden. Selbstverständlich wären diese Daten nur mit grossem Aufwand zu gewinnen (Fang-Wiederfang-Methode). Die bei den Begehungen gewonnenen Daten dürften allerdin...

Obschon an vielen Orten auf den negativen Einfluss intensiver Düngung von Wiesen auf die Lepidopteren hingewiesen wird, ist mir bis jetzt keine Arbeit bekannt geworden, welche die quantitativen und quantitativen Veränderungen, die mit der Düngung von Magerwiesen in des Lepidopterenfauna einhergehen, genauer erfasst. Dies mag seinen Grund wohl darin...

Durch die Wahl der Untersuchungsflächen sollte die tagaktive Lepidopteren-Fauna jedes Vegetationstyps möglichst klar und vollständig erfasst werden können. Infolgedessen wurde bei der Suche nach geeigneten Flächen in erster Linie darauf geachtet, dass diese eine möglichst geringe Heterogenität, aber doch eine möglichst grosse Ausdehnung aufwiesen....

Das Tavetsch ist ein relativ warmes und trockenes zentralalpines Tal, auch wenn es nicht als eigentliches inneralpines Trockental bezeichnet werden kann. Es ist klimatisch dem Obergoms vergleichbar (Bischof, 1980), wobei die Niederschläge im Tavetsch stärker auf den Sommer konzentriert sind als im Obergoms.

Eine ausgesprochen günstige Gelegenheit um die Enge der Biotopbindung der erfassten Lepidopterenfauna eines bestimmten Vegetationstyps zu überprüfen, bot sich am Südhang von Sedrun. Die bereits besprochene Extensivweide (WSe, s. S. 32) grenzt unmittelbar an die ebenfalls schon behandelte Fettwiese (FSe, s. S. 99). Die Untersuchungsflächen dieser be...

Die folgende systematische Faunenliste umfasst alle auf den Untersuchungsflächen gefundenen Arten. Ein Gesamtverzeichnis aller Funde sowie eine Belegsammlung sind beim Botanischen Institut der Universität Basel einzusehen. Soweit möglich, wurden alle Arten bis auf die Subspecies determiniert. Der Einfachheit halber habe ich in den Artenlisten und i...

Das Vegetationsbild der Südhänge des Tavetschs ist in den unteren, flacheren Partien vor allem durch gedüngte Mähwiesen geprägt. An den steileren Hängen dominieren die verschiedenen Brachestadien von Magerwiesen. Selten genug wird an der Übergangszone noch ein Stück ungedüngter Wiese gemäht. Als extensive Weide wird heute lediglich bei Sedrun eine...

Auf eine eingehende Darstellung und Diskussion der Phänologie der einzelnen Arten auf den verschiedenen Vegetationstypen soll in diesem Rahmen nicht eingegangen werden, obschon die Untersuchung die Grundlage dazu bieten würde. Ich möchte im folgenden lediglich einige wenige Fälle exemplarisch diskutieren.

Bis jetzt erfolgte die Diskussion hauptsächlich aus der Perspektive des Gesamtbestandes der erfassten Lepidopterenarten in den verschiedenen Vegetationstypen. Diese Perspektive kann aber auch umgedreht werden; als Fragestellung ergibt sich somit: Wie reagiert eine einzelne Art auf die durch die Verbrachung sich ergebende Sukzession der Vegetation?

Im Tavetsch (schweizerische Zentralalpen) wurden die Einflüsse von Brachlegung und intensiver Düngung extensiv bewirtschafteter Vegetation (Magerwiesen und Extensivweiden) auf die am Tage erfassbaren Grossschmetterlinge an über 30 Untersuchungsflächen verfolgt (Abb. 5, S. 18).

Die Berechnung von Diversitäts-Indices (gewichtete Diversität) setzt eine statistische Auswertung der Beobachtungen voraus und musste deshalb vorerst unterbleiben (s. S. 22). Den Diversitäts-Indices gegenüber gilt die blosse Artenzahl als ungewichtete Diversität (Pielou 1975) und ist nach Poole (1974) sogar das einzige wirklich objektive Mass für D...

Die untersuchten Fettwiesen gehören pflanzensoziologisch alle zu den Goldhaferwiesen, der Assoziation des Trisetetum flavescentis typicum (Marschall 1947, Hartmann 1976). Sie unterscheiden sich aber durch Exposition, edaphische Bedingungen und Intensität der Düngung (Hartmann 1976). Abbildung 22 zeigt die untersuchten Sukzessionsverhältnisse von Ma...