Bruno Baur

University of Basel | UNIBAS · Department of Environmental Sciences

Carabid beetles of the tribe Licinini use their asymmetric mandibles to open the shells of land snails. Prey handling of large snails has been described in a few Licinini species. We observed for the first time how a male of Licinus depressus (Paykull, 1790) opens the shells of small prey snails ( Chondrina arcadica (Reinhardt, 1881)) and eats thei...

Horticultural trade is considered the most important pathway for the introduction of non- native plant species. Numerous horticultural plants are spreading from private gardens and public green space into natural habitats and have the potential to alter native biodiversity and ecosystem functioning. We assessed the invasiveness of the horticultural...

We synthesize findings from a 7-year fragmentation experiment in species-rich, nutrient-poor, dry calcareous grasslands in the north-western Jura mountains, Switzerland. We used a standardized approach with 48 fragments (0.25–20.25 m2) and corresponding control plots in three sites. The 5-m-wide isolation area around the fragments was maintained by...

Knowledge of patterns of genetic diversity in populations of threatened species is vital for their effective conservation. However, destructive sampling should be avoided in threatened species so as not to additionally increase the risk of local population extinction. We exclusively used beetle remains and beetles collected after death to analyze l...

Elevational gradients along mountain slopes offer opportunities to study key factors shaping species diversity patterns. Several environmental factors change over short distances along the elevational gradient in predictable ways. However, different taxa respond to these factors differently resulting in various proposed models for biodiversity patt...

In the past, the freshwater snail Theodoxus fluviatilis was abundant in the river Rhine, but was considered to be extinct in the Upper and High Rhine in 2004. We found individuals of T. fluviatilis for the first time at sites in the southern part of the Upper Rhine and High Rhine in 2020, where this species went extinct 16 years ago. There are seve...

The fragmentation of continuous habitats has significant consequences for species and for the functional diversity of plant and animal communities. Fragmentation effects can be indirect, can occur at different spatial scales and may vary over years. Small fragmentation-related effects may only be detected in standardized, controlled field experimen...

Variation in community composition and species turnover are different types of beta diversity, expressing non-directional and directional changes, respectively. While directional changes (e.g. turnover) along geographic gradients can be studied in any direction depending on the hypothesis of interest to researchers, temporal changes can only be mea...

Urbanization is occurring around the globe, changing environmental conditions and influencing biodiversity and ecosystem functions. Urban domestic gardens represent a small-grained mosaic of diverse habitats for numerous species. The challenging conditions in urban gardens support species possessing certain traits, and exclude other species. Functi...

Riassunto: L'urbanizzazione è tra le principali cause dell'omogeneizzazione della biodiversità e favorisce la diffusione di specie alloctone negli ambienti naturali. Questo studio esamina l'influsso degli insediamenti suburbani e della composizione del pae-saggio circostante sulla diffusione di piante alloctone nelle foreste della Svizzera meridion...

Stadtwälder haben für die Menschen verschiedene Funktionen und sind gleichzeitig der Lebensraum von zahlreichen Pflanzen-und Tierarten. Eine neue Studie zeigt, dass in urbanen Wäldern die Vielfalt der totholzabbau-enden Pilze und Insekten deutlich geringer ist als in Wäldern im ländlichen Raum. Es wird empfohlen, Totholz auch in urbanen Wäldern zu...

In the field, hatchlings of H. pomatia were observed to consume sibling eggs (= within-batch cannibalism) as well as eggs from neighboring batches (= between-batch cannibalism). Egg cannibalism occurs in H. pornatia exclusively during the hatchling stage, and only conspecific egts are eaten. Recognition of related individuals might be important for...

• Climate warming is predicted to result in changes to phenology, behaviour and abundance as well as poleward shifts or upslope displacements of the distribution of species. However, climate-warming induced changes in distribution patterns have rarely been studied in ground-dwelling arthropods. • We investigated changes in the upper elevational lim...

Aim Forests provide important ecosystem services and are often the only natural areas that are freely accessible to the public for outdoor recreation. Large numbers of forest visitors can cause severe damage to forest ecosystems, which in turn can affect the ecosystem functioning. We aimed to assess whether experimental short-term and long-term tra...

Urban gardens are important for human well-being, biodiversity and other ecosystem functions. Biodiversity-promoting initiatives would benefit from their owners being aware of the state of biodiversity in their gardens. We examined whether garden owners’ perceptions match actual biodiversity in their gardens and whether perceptions are influenced b...

Pestizide werden primär in der Landwirtschaft, aber auch im Siedlungsraum und in weiteren Bereichen eingesetzt. Als Pflanzenschutzmittel vermindern sie Ertrags- oder Qualitätseinbussen durch Schadorganismen. Der heutige Pestizideinsatz belastet aber die Umwelt und insbesondere die Biodiversität beträchtlich. Trotz Wissenslücken sind die unerwünscht...

Population size of species with birth-pulse life-cycles varies both within and between seasons, but most population dynamics models assume that a population can be characterised adequately by a single number within a season. However, within-season dynamics can sometimes be too substantial to be ignored when modelling dynamics between seasons. Typic...

In der Schweiz nimmt die Anzahl Pflanzenarten, die aus anderen Kontinenten eingeführt werden, stetig zu. Diese gebietsfremden Arten können verwildern und haben das Potenzial, einheimische Pflanzenarten zu verdrängen, wirtschaftliche Schäden zu verursachen oder die Gesundheit der Menschen zu gefährden. Viele dieser Arten werden als Zierpflanzen für...

Textbook on conservation biology

Urbanization is increasing worldwide and is regarded a major threat to biodiversity in forests. As consequences of intensive human use, the vegetation structure of naturally growing urban forests and their amount of deadwood can be reduced. Deadwood is an essential resource for various saproxylic insects and fungi. We assessed the effects of urbani...

Naturschutzbiologie ist eine relativ junge wissenschaftliche Disziplin, deren Ziel die Erarbeitung der Grundlagen für die Erhaltung und Förderung der biologischen Vielfalt (Biodiversität) und der Ökosystemleistungen ist. Dieses Lehrbuch behandelt die wichtigsten Aspekte der Naturschutzbiologie, stellt neue Ergebnisse der Forschung vor und zeigt der...

Environmental change as result of urbanisation can influence soil microbial communities in green areas. In cities, forests are among the most frequent types of green areas and provide a wide variety of ecosystem services for the residents, such as air cleaning, nutrient cycling and area for recreational activities. Mycorrhizal fungi play an importa...

Effects of distance to the city centre (three classes) on the Sørensen-indices of species compositions of gastropods (a), spiders (b), millipedes (c), woodlice (d), ants (e), and rove beetles (f). The Sørensen-indices of species compositions were calculated for all combinations of each two gardens belonging to the same distance class. Different let...

Effects of percentage of sealed area within a radius of 200 m (three classes) on the Sørensen-indices of species compositions of gastropods (a), spiders (b), millipedes (c), woodlice (d), ants (e), and rove beetles (f). The Sørensen-indices of species compositions were calculated for all combinations of each two gardens belonging to the same distan...

Results of constrained analyses of principle coordinates visualizing similarities in species compositions of gastropods (a), spiders (b), millipedes (c), woodlice (d), ants (e), and rove beetles (f) in gardens with different percentages of sealed area within a radius of 200 m (three classes). Dark red refers to gardens with a high percentage of sea...

Summaries of GLMs testing the effects of landscape factors (distance to city centre or percentage of sealed area in the surroundings), garden size (area with vegetation) and local garden characteristics, as well as of the interaction between the landscape factors and garden size on species richness and abundance of different taxonomical groups.

Urbanisation is increasing worldwide and is regarded a major driver of environmental change altering local species assemblages. Private domestic gardens contribute a significant share of total green area in cities, but their biodiversity has received relatively little attention. Previous studies mainly considered plants, flying invertebrates such a...

Abstract (Paper is in German language!) Successful action in conservation calls for close exchange and effective feedback between science and practitioners at all levels. However, many examples and experiences indicate that this mutual exchange does not function optimally nor according to requirements. From the authors' point of view, there is a ne...

A single specimen of Anotylus politus was captured in Riehen (BS) in 2014. This is the first record of the species in Switzerland.

As elements of green infrastructure, railway embankments are important corridors in urban environments connecting otherwise isolated habitat fragments. They are interrupted when railways cross major roads. It is not known whether dispersing animals use railway bridges to cross roads. We examined the function of a set-aside iron-steel railway bridge...

World‐wide decreases of insect abundance and diversity are of major concern because of their importance for ecosystem functioning and the stability of ecosystems. Various studies reported dramatic declines of butterflies, wild bees and beetles in agricultural areas. Yet, evidence for decreasing abundance in cryptic insect species is scarce. Using a...

Urbanisation is increasing globally and is considered to be a main driver of environmental change. Urbanisation-related factors include reduced habitat size and increased spatial isolation of the remaining habitats. As a consequence, the dynamics of plant and animal populations may change, which in turn might influence the quality and quantity of p...

Urbanisation is an important driver of environmental change and has the potential to alter the functioning of ecosystem processes. In urban forests, a key ecosystem process is litter decomposition, which is driven by thelitter quality and composition of litter fauna. We examined whether the degree of urbanisation and forest size influence litter de...

Extensively managed semi-natural grasslands represent species-rich habitats and therefore play a key role for the maintenance of biodiversity in agricultural areas. In marginal and poorly accessible areas, the traditional management of grassland is frequently abandoned, which leads to the spread of forest. In Southern Switzerland, terraced vineyard...

The invasive box‐tree moth Cydalima perspectalis causes damage to horticultural box trees (Buxus spp.) in private gardens and parks in Europe and defoliation of large areas of European native box trees Buxus sempervirens, which grow in the understorey of deciduous forests. In some parts of their distribution area, wild native box trees are infected...

Invasive plant species can significantly affect native biodiversity and ecosystem functioning. Even though the majority of ecosystems have more than 50% of the plant biomass belowground, most studies investigating the effects of invasive species on plant diversity focus on the aboveground vegetation. New DNA-based methods allow the determination of...

Soil fungi play a crucial role in ecosystem functioning and there is increasing evidence that exotic plants invading forests can affect soil fungal communities. We examined potential effects of the invasive plant Impatiens glandulifera on hyphal biomass of ectomycorrhizal fungi, their genetic diversity and the diversity of other soil fungi in decid...

In Schweizer Wäldern nimmt die Zahl der nicht-einheimischen Pflanzen- und Straucharten stetig zu. Viele dieser Arten werden als Zierpflanzen aus anderen Kontinenten eingeführt und verwildern später. Am Beispiel des Kirschlorbeers wird gezeigt, wie dieser die einheimische Artenvielfalt in Wäldern reduziert.

Most invading alien plants affect native biodiversity and ecosystem functioning. In a field survey, we assessed the impact of the invasive shrub Prunus laurocerasus on the native vegetation and soil properties in suburban deciduous forests in the region of Basel, Switzerland. We installed four pairs of plots in patches of P. laurocerasus and in adj...

Habitat loss and fragmentation are among the biggest threats to biodiversity. Anthropogenic habitat fragmentation leads to small and isolated remnant plant and animal populations. The combination of increased random genetic drift, inbreeding, and reduced gene flow may substantially reduce genetic variation of remnant populations. However, the magni...

Urbanisation is increasing worldwide and is regarded a major driver of environmental change altering local species assemblages in urban green areas. Forests are one of the most frequent habitat types in urban landscapes harbouring many native species and providing important ecosystem services. By using a multi-taxa approach covering a range of trop...

Species–site matrices for plants, ants, and spiders. For the arthropod survey, the number of recollected traps per forest site is presented. (XLSX)

Functional dispersion: Summary of ANCOVAs of plants. Summary of ANCOVAs examining the effects of degree of urbanisation, forest size and shape, forest management (time since last thinning), disturbance (indicated by path density), canopy closure, soil characteristics (moisture, pH, soil organic nitrogen (orgN) and phosphorus (orgP) content) and cov...

Forest specialists in relation to size and shape of urban forests. Percentage forest specialist species of a) ants and b) spiders in fragments of different size; size classes are small (< 4000 m2), medium-sized (4000–10,000 m2) and large (> 10,000 m2); and c) percentage of forest specialist species of plants depending on the shape of the fragment....

Landscape, forest and plot characteristics recorded during field surveys. (XLS)

Correlations within and among landscape and site characteristics. Results of Pearson’s (r) and Spearman’s rank (rs) correlation, Contingency table (χ2-test) and Kruskal-Wallis test examining the relationship between observed species richness and rarefied species richness (a) and among landscape and forest characteristics for all three taxonomic gro...

Data used to perform PERMANOVA. (XLSX)

Description of forest sites. Characteristics of the 26 forests examined in Basel (Switzerland) and its surroundings. (DOCX)

Functional dispersion: Summary of ANCOVAs of ants and spiders. Summary of ANCOVAs examining the effects of degree of urbanisation, forest size and shape, forest management (time since last thinning), disturbance (indicated by path density), canopy closure, soil organic matter content, litter characteristics (moisture, pH) and structural diversity m...

Species and trait lists. Species list of (a) vascular plants, (b) ants and (c) spiders. Habitat specificity, conservation status (Red List) and a set of traits, which we considered to influence species’ response to urbanisation-related factors are shown. Traits not used for analyses are in parentheses. (DOCX)

Percentage of sites in which common species occur for different degrees of urbanisation and forest size classes. Common species are defined as occurring in at least 10 of the sites. Means are given for less common species. (XLS)

Limestone cliffs in the Jura Mountains harbour species-rich plant and animal communities including rare species. Sport climbing has recently increased in popularity in this habitat and several studies have reported damage to cliff biodiversity. However, so far how damage levels vary with climbing intensity has not been investigated. We evaluated th...

Invasive plants may severely impact native biodiversity and ecosystem functioning. We examined potential effects of the invasive annual plant Impatiens glandulifera Royle on soil fungal and bacterial communities in temperate forests. Using a space-for-time approach, we established 72 plots in forest areas invaded by I. glandulifera and in forest ar...

Urban growth is considered to be a major driver of environmental change. Urbanisation can affect urban biodiversity in different ways. So far, most studies focused on the impact of urbanisation on single taxa in one habitat type. In this study, we used data of species inventories and GIS-based landscape elements to examine the effects of habitat si...

Environmental changes associated with urbanisation can affect the functioning of ecosystem processes. In cities, forests are among the most frequent types of green areas and provide a wide range of ecosystem services including air cleaning, decomposition of leaf litter and recreation. The European beech (Fagus sylvatica) is a frequent and widesprea...

Biodiversity is being lost at alarming rates in spite of efforts to conserve ecosystems, species and genetic diversity. There is broad consensus that biodiversity conservation needs to become more effective, and this requires an analysis of the causes that have prevented previous efforts from reaching their goal. A lack of knowledge exchange and co...

The Article cirtically reviews the book.

Invasions by alien plants significantly affect native biodiversity and ecosystem functioning. We conducted a 5-year field experiment to investigate potential effects of the annual invasive plant Impatiens glandulifera on both the native above-ground vegetation and soil seed bank in a deciduous forest in Switzerland. Eight years after the establishm...

Urbanization is considered as a major driver for biotic homogenization. Urbanization also promotes the dispersal of non-native species. This study examined the roles of suburban settlements and of the surrounding landscape composition for the spread of non-native plant species into adjacent mixed deciduous forests in Southern and Northwestern Switz...

Exposed limestone cliffs in the Swiss Jura Mountains harbour a diverse gastropod community with some rare species. Sport climbing has recently increased in popularity on these cliffs. We examined the effects of sport climbing and microtopographical features of rock faces on terrestrial gastropods by assessing species diversity and abundance on clim...

The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used t...

The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used t...

The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used t...

Conservation programs increasingly involve the reintroduction of animals which otherwise would not recolon-ize restored habitats. We assessed the long-term success of a project in which the Blue-winged grasshopper, Oedipoda caerulescens (L., 1758), was reintroduced to a nature reserve in Northwestern Switzerland, an alluvial gravel area where the s...

Background: Sperm size and quality are key factors for fertilization success. There is increasing empirical evidence demonstrating that sperm form and function are influenced by selective pressures. Theoretical models predict that sperm competition could favour the evolution of longer sperm. In hermaphrodites, self-fertilizing species are expected...