Functionally richer communities improve ecosystem functioning: Dung removal and secondary seed dispersal by dung beetles in the Western Palaearctic

Aim: In several ecosystems, the diversity of functional species traits has been shown to have a stronger effect on ecosystem functioning than taxonomic diversity alone. However, few studies have explored this idea at a large geographical scale. In a multisite experiment, we unravelled the relationship between ecosystem function and functional completeness of species assemblages using dung beetles as a model group, focusing on dung removal and secondary seed dispersal. Location: Seventeen grassland locations across the Western Palaearctic. Methods: We used a randomized block design with different exclosure types to control the dung and seed removing activities of individual functional groups of the local dung beetle assemblage. We classified dung beetle species according to resource specialization and into functional groups based on dung processing behaviour (dwellers, tunnellers, rollers) and body size (small, large). Additionally, we assessed the role of other soil macro‐invertebrates. By sampling the dung beetle community and measuring the remaining dung and seeds after the experiment, the impact of each functional group was estimated. Results: Dung beetle assemblages differed along a north–south and east–west gradient. Dwellers dominated northernmost sites, whereas at lower latitudes we observed more tunnellers and rollers indicating a functional shift. Resource specialists were more abundant in southern and eastern areas. Overall, functional group diversity enhanced dung removal. More dung (+46.9%) and seeds (+32.1%) were removed in the southern sites and tunnellers and rollers were more effective. At the northernmost sites, where tunnellers were scarce or absent, other soil macro‐invertebrates removed the majority of dung. Main conclusions: The conservation of functionally complete dung beetle assemblages is crucial to maintain the ecosystem functions provided by dung beetles. Given the latitudinal variation in functional group diversity, it is reasonable to expect compositional changes due to climate change. These changes could lead to increased dung removal and a higher secondary seed dispersal rate in northern regions

Dung beetle assemblages, dung removal and secondary seed dispersal: data from a large-scale, multi-site experiment in the Western Palaearctic

By manipulating faeces during feeding and breeding, dung beetles (Coleoptera: Scarabaeidae) fulfil important ecosystem functions in terrestrial ecosystems throughout the world. In a pan-European multi-site experiment (MSE), we estimated the ecosystem functions of dung removal and secondary seed dispersal by differing combinations of dung beetle functional groups. Therefore, we classified dung beetles into five functional groups according to their body size and dung manipulation method: dwellers, large and small tunnelers, and large and small rollers. Furthermore, we set up a dung beetle sampling database containing all sampled dung beetles during the project. By identifying dung beetle specimens to the species level, we obtained a detailed insight into the dung beetle communities at each study location. By establishing experimental plots allowing and inhibiting specific combinations of functional groups in the local dung beetle assemblage from removing dung and seeds, we estimated the role of each group in dung removal and secondary seed dispersal during a 4-week period. We performed all experiments in grazed (semi-)natural grasslands, and used different dung types (cattle, horse, sheep, goat or red deer) to match the herbivore species grazing in close vicinity of each of the study areas. Simultaneously, we sampled dung beetle assemblages by using pitfalls baited with the same dung types as used in the experiments. This data paper documents two datasets collected in the framework of this MSE project. All the experiments took place between 2013 and 2016 at 17 study sites in 10 countries and 11 biogeographic zones. The entire dung beetle sampling dataset was published as a sampling event dataset at GBIF. The dataset includes the sampling results of all 17 study sites, which contain 1,050 sampling events and 4,362 occurrence records of 94 species. The second dataset contains the results of the dung removal and secondary seed dispersal experiments in which we used 11 experimental treatments and the five dung types mentioned above. This experimental results dataset holds all experimental results of the MSE project (11,537 records), and was published in the online data repository Zenodo

Relationships of plant species composition, phytodiversity and soil variables in fens and related habitat types in Luxembourg

In Luxemburg sind infolge von Landnutzungsintensivierungen nur noch wenige Relikte nährstoffarmer Feuchthabitate mit hohem Naturschutzwert erhalten. Eine kleinräumig differenzierte Untersuchung der Zusammenhänge zwischen Bodenfaktoren und Vegetation stand für diese Relikte bisher aus. Aus diesem Grund wurden in fünf Luxemburger Niedermoorkomplexen Vegetationszusammensetzung, Vegetationsstruktur (90 %-Perzentil der Vegetationshöhe, Streudeckung) und für die Pflanzenernährung relevante, bodenchemische Variablen (pH-Wert, Phosphor-, Kalium-, Calcium-, Magnesium-Gehalt) erfasst sowie Ellenberg-Zeigerwerte (Feuchte- und Nährstoff-Zahl) ausgewertet. Dabei ging es insbesondere um die Klärung der Fragen, welche Umweltgradienten der auffälligen Zonierung in Kern- und Randbereiche zugrunde liegen und welche Habitateigenschaften mit der Anzahl von gefährdeten Arten korrelieren. Hierzu wurden insgesamt 74 Kleinflächen in den beiden Zonen angelegt und floristisch sowie bodenchemisch analysiert. Die Kleinflächen spannten einen Säuregradienten von annähernd drei pH-Stufen über die Gebiete hinweg auf (pH 3,9–6,5). Es ließen sich floristische, strukturelle und bodenchemische Unterschiede zwischen den Zonen ausmachen. In den meisten Gebieten unterschieden sich Diversität (in Kernbereichen erhöht) und Produktivität (nach Maßgabe von 90 %-Perzentil und Nährstoff-Zahl in Randbereichen erhöht). Die bodenchemischen Variablen zeigten je nur in einzelnen Gebieten Zonenunterschiede. Die beiden Gebiete mit den niedrigsten bzw. höchsten pH-Werten wiesen die meisten Variablen mit signifikanten Zonenunterschieden auf. Die Feuchte-Zahl war in keinem Gebiet zonenkennzeichnend. Die Diversität an bedrohten Arten korrelierte am häufigsten mit dem Magnesiumgehalt im Boden (meist positiv) und dem 90 %-Perzentil (stets negativ). Unsere Ergebnisse legen nahe, dass in den untersuchten Niedermoorkomplexen mehrere Variablen zugleich und in unterschiedlicher Kombination für die Zonation verantwortlich sein könnten. Es werden Managementoptionen für die gefährdeten Gebiete diskutiert.In Luxembourg, as a consequence of land use intensification, there are only few relicts of nutrient-poor wetland habitats with a high conservation value left. Up to now, a small-scale spatial analysis of the relationships between soil factors and vegetation has not been published for these relicts. For this reason, we assessed vegetation composition, vegetation structure (90% percentile of the vegetation height, litter cover), soil variables relevant for plant nutrition (pH value, contents of phosphorous, potassium, calcium, magnesium) and Ellenberg indicator values (EIV-N, EIV-F) in five fen complexes in Luxembourg. The central questions were: Which environmental gradients explain the obvious zonation patterns (core and fringe zones) and which habitat qualities correlate with the number of threatened plant species? Therefore, in total, 74 smallsized quadrats were established in both core and fringe zones and vegetation and soil samples were analyzed. The quadrats differed clearly in soil pH value across study areas (pH range: 3.9–6.5). There were floristic, structural and soil chemical differences between the zones. In most areas, zones differed in diversity (higher in core zones) and productivity (in terms of 90% percentile and EIV-N higher in fringe zones). Soil chemical variables showed only in single areas differences between zones. The two areas with the lowest and highest pH values, respectively, showed the highest numbers of significantly differing variables between zones. In all areas, EIV-F was similar in the two zones. The diversity of threatened species correlated most frequently with the contents of magnesium in soil (mostly positively) and the 90% percentile (always negatively). We conclude that different factors might cause the zonation in fen complexes. Options for the management of the threatened areas are discussed

Extensive Beweidung mit domestizierten Großherbivoren zur Erhaltung und Wiederherstellung der Pflanzendiversität im temperaten Europa

The continuous decline in biodiversity in some European landscapes has led recently to the (re-) implementation of low-intensity grazing systems as an alternative to more cost-intensive conservation practices. This approach aims at developing habitat complexes comprising various successional stages and increasing plant species diversity on local (a-diversity) and landscape scales (b-, y-diversity). The primary objectives of this review were to uncover ecological processes in which large domestic herbivores (cattle, equids, sheep, goats, pigs) have a key function in affecting plant diversity and to provide a framework for future research and conservation practices. The reviewed literature covers a wide range of ecosystem types in various temperate regions of Europe with a main focus on recent results from Central Europe. Low-intensity grazing enhances existing environmental gradients and generates manifold disturbance patterns on various spatial scales resulting in high habitat diversity. Livestock trampling has a so far underestimated impact on plant species composition and richness. Additionally, selective herbivore behavior facilitates the coexistence of plant species representing different functional types including a considerable number of threatened and grazing-sensitive species. Co-occurrence of progressive and regressive successional processes on low-intensive pastures results in a high b- and y-diversity, an effect that has been observed soon after the (re-)implementation of grazing. Persistence of speciespoor successional stages of dominant competitive graminoid and herb species can in many cases be inhibited by grazing. Large domestic herbivores serve as effective vectors for the dispersal of diaspores, thus improving the connectivity of isolated plant populations. There is a combined effect of diaspore dispersal and microsite creation which can increase the probability of diaspores to successfully germinate and establish. Overall, low-intensity grazing represents a highly flexible concept to maintain and restore plant diversity in cultivated landscapes; general management implications are given.Der kontinuierliche Rückgang der Biodiversität in einigen europäischen Landschaften hat in der jüngeren Vergangenheit zu einer Wieder- bzw. Neu-Einführung von extensiven Beweidungssystemen geführt, die eine kostengünstigere Alternative zu anderen Naturschutzmaßnahmen darstellen. Dieser Ansatz hat die Entwicklung von Habitatkomplexen zum Ziel, die verschiedene Sukzessionsstadien umfassen und die Pflanzendiversität auf Habitat- (a) und Landschaftsebene (b-, y-Diversität) erhöhen. Die Hauptziele unseres Reviews lagen zum einen darin, ökologische Prozesse zu bestimmen, die von Weidetieren (Rindern, Pferdeartigen, Schafen, Ziegen, Schweinen) beeinflusst oder initiiert werden und die eine Schlüsselrolle beim Aufbau der pflanzlichen Diversität spielen, zum anderen darin, einen Rahmen zu schaffen für zukünftige Forschung und Naturschutzpraxis. Die ausgewertete Literatur beinhaltet ein breites Spektrum an Ökosystemtypen in verschiedenen gemäßigten Regionen Europas (Schwerpunkt Mitteleuropa). Extensive Beweidung führt zu einer Verstärkung bestehender Umweltgradienten und erzeugt vielfältige Störungsmuster auf verschiedenen Skalenebenen. Dies führt zu einer hohen Habitatdiversität. Der Einfluss von Tritt auf die Pflanzenartenzusammensetzung und die Artendiversität (Bereitstellung von Keimungsnischen) wurde in seiner Vielfältigkeit und Bedeutung bisher unterschätzt. Auch das selektive Fraßverhalten von Weidetieren fördert die Koexistenz von Pflanzenarten verschiedener funktioneller Typen, einschließlich bedrohten und beweidungsempfindlichen Arten. Das gleichzeitige Vorliegen von progressiven und regressiven Sukzessionsprozessen führt zu einer hohen b- und y-Diversität. Dieser Effekt kann sich sehr schnell nach der (Wieder-)Einführung von extensiver Beweidung einstellen. Beweidung kann in vielen Fällen die Monodominanz von konkurrenzstarken grasartigen und krautigen Pflanzenarten in persistenten, artenarmen Beständen mindern. Als effektive Diasporenvektoren unterstützen Weidetiere die Vernetzung von isolierten Pflanzenpopulationen. Infolge einer räumlich-funktionellen Verknüpfung von Diasporenausbreitung und Störstellenschaffung werden Keimungs- und Etablierungsraten von Zielarten in vielen Fällen erhöht. Insgesamt zeigt sich, dass extensive Beweidung ein sehr flexibles Konzept darstellt, um die Pflanzendiversität in Kulturlandschaften zu erhalten und wiederherzustellen. Es werden allgemeine Handlungsempfehlungen für die Beweidungspraxis gegeben

Endozoochorous dispersal, seedling emergence and fruiting success in disturbed and undisturbed successional stages of sheep-grazed inland sand ecosystems

This study examines the seedling emergence and fruiting success of plant species endozoochorously dispersed by sheep in a field experiment in a Koelerion glaucae area. We designed a factorial experiment (faeces/soil disturbance/successional stage/year) that mimics sheep-mediated microsites and analysed all occurring vascular plant species from September 2002-December 2004. The faeces samples were collected in the same ecosystem and additionally analysed in a common-garden experiment (seedling emergence potential). According to the latter, 28 vascular plant taxa were identified (on average 124 seedlings per 100g air-dry sheep faeces). In the field, 15 species emerged directly out of faeces, only five of which were able to set seeds (the threatened species Medicago minima, Phleum arenaritan, Silene conica, Vicia lathyroides and the non-threatened Vulpia mytiros). Graminoid competitors were not able to set seedlings in the field but did so in the common-garden experiment (mainly Carex hirta). The total numbers of seedlings emerging out of faeces (5% of the potential) and reaching fruit ripeness (0.4%) were very low. In the stage of seedling emergence, ten of 42 species were significantly influenced by faeces, 11 species by disturbance and two species by an interaction of the two treatment factors (Bromus tectorum, Saxifraga tridactylites). In the fruiting stage, two species profited by faeces (Bromus tectorum, Vulpia myuros) and two species by disturbance (Erophila verna, Corynephorus canescens). Overall, the density and diversity of fruiting individuals were significantly influenced by both treatment factors. The faeces factor showed a strong dependence on year (increasing effect on both dependent variables in the first year, decreasing effect in the second year). The disturbance factor is dependent particularly on successional stage (increasing effect especially in the later successional stage). Our study revealed the paradox that threatened species with low nutrient demands are the most successful direct colonisers of sheep-faeces deposits. For them to reach the fruiting stage is rare but is of importance if new habitats are to be made accessible. (c) 2006 Elsevier GmbH. All rights reserved