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Recent reports have shown a dramatic loss in insect species and biomass. Since forensic entomology relies on the presence of insects, the question is whether this decline effects the discipline. The present review confirms that numerous studies document insect population declines or even extinction, despite the fact that the rates of decline and the methods used to demonstrate it are still much debated. However, with regard to a decline in necrophagous insects, there is little or only anecdotal data available. A hypothetical decrease in species diversity and population density in necrophagous insects could lead to a delayed colonization of dead bodies and a modified succession pattern due to the disappearance or new occurrence of species or their altered seasonality. Climate change as one of the drivers of insect decline will probably also have an impact on necrophagous insects and forensic entomology, leading to reduced flight and oviposition activity, modified growth rates and, therefore, an over- or underestimation of a minimum postmortem interval. Global warming with increased temperature and extreme weather requires a better understanding about necrophagous insect responses to environmental variations. Here, transgeneration effects in particular should be analysed in greater depth as this will help to understand rapid adaptation and plasticity in insects of forensic importance.
Central European temperate forests are – with the exception of floodplain forests – relatively little invaded by alien plants. However, despite substantial recent progress, there is still a lack of using vege-tation plot data for analyzing spatio-temporal patterns of alien tree species invasions.
We calculated relevé-based metrics of tree species’ ecological preferences using 19,413 phytosociological forest relevés of the Austrian vegetation database. We focused on the five most widely distributed alien trees, i.e. two archaeophytes (Castanea sativa, Juglans regia) and three neophytes (Acer negundo, Ailanthus altissima, Robinia pseudoacacia). For each of these species we analyzed the mean cover in the tree layer and the occurrence in the herb and shrub layers in relevés colonized by adult trees as a measure for persistence. Further, we evaluated the intergenerational ecological plasticity (= the ability of young trees to grow under different site conditions than adults) for the tree species, and the mean relevé indicator values for light, nutrients, moisture and hemeroby. We then compared these alien and native tree species metrics.
We found that A. altissima and R. pseudoacacia build up high mean cover values in invaded forests, but this was not the case for the other alien trees. Thus, both species strongly affected forest communities of invaded sites. Similarly, the two species were common in the lower vegetation layers indicating recruitment under the canopy of adult conspecifics; this was facilitated by their ability to produce root suckers. Highest values of inter-generational ecological plasticity occurred in native pioneer trees and species of softwood floodplain forests, while alien trees had moderately high (A. negundo, A. altissima, J. regia) to low values (C. sativa, R. pseudoacacia). With the exception of C. sativa, all alien species showed high mean Ellenberg indicator values for light and nutrients, and were more common in sites with high hemeroby and high mean Ellenberg indicator values for temperature. Distinct from the ecological preferences of alien trees, and thus rarely invaded, were montane beech forests, coniferous mountain forests and forests at extremely dry sites, as well as swamp and bog forests dominated by willows and ash.
We conclude that relevé-based metrics of the behavior of alien tree species allow new insights into the spatio-temporal dynamics of invasion of woody species in forests. Future work should expand this approach, e.g., by considering the role of life history traits and actual site conditions.
This study describes the vascular flora and community structure of grasslands occurring on heaps of waste rock left by former Zn-Pb mining in relation to the metal content in the soil and other environmental factors. The study was performed on 65 heaps scattered in agricultural land in southern Poland. The sites were described in terms of plant community characteristics, soil physicochemical properties, distance from woodland, altitude and local climate. The number of plant species and proportion of species of the Festuco-Brometea class decreased with increasing heavy metal (Cd, Pb, Zn) content in the soil, and increased with Ca content and pH of the soil. There was a negative relationship between the proportion of the later successional species and heavy metal content in the soil and a positive relationship between plants connected with the earlier stages of succession and metals. Floristic composition was also affected by distance from woodland and height above sea level. The investigated heaps were primarily colonised by native species dispersed by wind, characterised as competitive stresstolerant, ruderal and competitive strategy species. Three types of Carlino acaulis-Brometum erecti (CB) communities were distinguished: CB typicum – dominated by Brachypodium pinnatum, with the highest proportion of calcareous grassland species, CB festucetosum ovinae subass. nova – loose grassland with abundant facultative metallophytes, and the CB rubietosum caesi subass. nova with nutrientdemanding ruderal and woody plants invading from the nearby forest communities. The three subassociations represent different successional stages of Carlino acaulis-Brometum erecti, strongly dependent on both the substrate and spatial relations. The proportions of species traits, especially a high occurrence of endangered species and a very low proportion of alien species show that the post-mining habitats studied have a similar degree of ‘naturalness’ as valuable xerothermic grasslands on nonmetalliferous habitats. They thus may be considered as valuable objects for the protection of plant diversity.
Inland sand vegetation, in our case steppic sandy grassland on base-rich soils, is highly endangered in Europe and therefore in the focus of restoration ecology. While there are studies which deal with short-term restoration success, results for an extended time are rare. We were able to analyse the success of a three-step restoration measure for 10 years.
The experiment was established on an exarable field in the Upper Rhine valley, Hesse, Germany. The three-step restoration approach comprised 1) abiotic restoration by deep-sand deposition, 2) inoculation with raked/mown plant material from two different donor sites with well-developed Koelerion glaucae/Allio-Stipetum vegetation and 3) low-intensity grazing by donkeys. The vegetation of the restoration and donor sites (also serving as reference sites to assess restoration success) was sampled on six permanent plots, respectively. Data analyses included ordination, classification and target-species ratios (TSR: relation of target species to all species).
Detrended correspondence analysis revealed a continuous succession of the restoration plots towards the corresponding reference plots: open soil decreased, ruderal species declined and target species increased. While speed of succession decreased, there was still a further improvement in the tenth year. The qualitative TSR (number of target species) reached a plateau after the sixth year with values only slightly lower than at the reference sites. The quantitative TSR (cover of target species) showed a steady improvement and even excelled one reference site. Koelerion glaucae species were present with constancy 17–67% since the 3rd year, with 33–100% since the 7th year. It does not completely resemble either reference site due to a mixture of propagules of both donor sites (e.g. by wind and donkeys) and input from the surroundings. Already in the first year, three Red-list species established themselves, since the 8th year 23 Red-list/near-threatened species have been present. Some ruderal species colonised the restoration site and occurred permanently.
Additionally, we studied the establishment of the highly threatened species Bassia laniflora after inoculation for 6–12 years on three further plots adjacent to the other ones. One of these plots was located on a former sandy field without abiotic restoration; two other plots represented typical Koelerion glaucae vegetation on a newer deep-sand deposition. Bassia laniflora established itself well on all plots. We conclude that restoration of steppic sandy grassland, including highly threatened species, was not only permanently, but increasingly successful over a time span of 10 years. Management by grazing, however, will remain essential to suppress ruderalisation.
Um zu überprüfen, ob sich die Artenzusammensetzung alpiner Kalk-Magerrasen (Blaugras-Horstseggenrasen, Polsterseggenrasen) im Nationalpark Berchtesgaden während der letzten drei Jahrzehnte geändert hat, wurden Vegetationsaufnahmen aus den 1980er Jahren 2013/14 zum zweiten Mal wiederholt vegetationskundlich erfasst.
Ziel der Arbeit war es, durch den Vergleich der Aufnahmenkollektive Vegetationsveränderungen während der letzten drei Jahrzehnte aufzuzeigen und diese als allogene oder autogene Prozesse zu interpretieren. Dabei wurde insbesondere der Frage nachgegangen, ob anthropogene Stickstoff-Einträge als Hauptursache für mögliche Veränderungen angesehen werden können.
Tatsächlich konnten ausgeprägte floristische Veränderungen im Vergleichszeitraum aufgezeigt werden. So hat sich seit den 1980er Jahre die mittlere Artenzahl sowohl im Polsterseggenrasen als auch im Horstseggenrasen um mehr als 10 Arten pro Aufnahmefläche erhöht. Im Polsterseggenrasen wurde ferner eine signifikante Abnahme der mittleren Kontinentalitätszahlen nachgewiesen.
Die dokumentierten floristischen Veränderungen könnten auf die globale Erwärmung und die damit verbundenen Klimaeffekte zurückzuführen sein. Auch natürlich ablaufende Sukzessionsprozesse könnten die aufgezeigten Änderungen in der Artenzusammensetzung erklären, allerdings ist die Zeitspanne von 30 Jahren zu kurz, als dass eine autogene Sukzession als der Hauptfaktor angesehen werden kann. Denkbar ist aber, dass Sukzessionsprozesse durch die globale Erwärmung heutzutage beschleunigt ablaufen. Stickstoffeinträge oder Landnutzungsänderungen spielen als Erklärungsmodell für die Vegetationsveränderungen dagegen wohl eher eine untergeordnete Rolle.
Im östlichen Südtirol wurden Wiesen entlang der Gradienten Meereshöhe, Bodenfeuchtigkeit, Bewirtschaftungsintensität über saurem bzw. basischem Gestein erhoben und in 12 Vegetationstypen gegliedert. Sie wurden durch numerische Syntaxonomie bzw. den rechnerischen Vergleich mit einer Auswahl von Tabellen aus der Literatur den entsprechenden Pflanzengesellschaften zugeordnet. Aus den Beschreibungen der jeweiligen Syntaxa wurde die Bewirtschaftungsintensität abgeleitet. Dies führte zur Differenzierung von extensiven (ungedüngten), halbintensiven (schwach bis mäßig gedüngten, ohne flüssige Wirtschafts- und Mineraldünger) und intensiven (reichlich gedüngten, meist mit Gülle) Wiesentypen. Da sich die Stickstoffzahlen signifikant unterschieden, stellen die Wiesentypen zuverlässige Indikatoren für die jeweiligen Bewirtschaftungsintensitäten dar. Intensivwiesen wiesen mittlere Stickstoffzahlen über 6,0 auf und wurden dem Poo-Trisetetum poetosum trivialis zugeordnet, halbintensive Wiesen mit Stickstoffzahlen zwischen 4,0 und 5,0 gehören dem Poo-Trisetetum arrhenatheretosum, dem Trisetetum flavescentis typicum bzw. -nardetosum und dem Angelico-Cirsietum oleracei an. Extensive Wiesen hatten durchschnittliche Stickstoffzahlen unter 4,0 und gehören dem Potentillo erectae-Brachypodietum pinnati brometosum erecti und -avenuletosum praeustae, dem Sieversio-Nardetum strictae typicum und -festucetosum nigricantis, dem Carlino-Caricetum sempervirentis, dem Campanulo scheuchzeri-Festucetum noricae und der Scheuchzerio-Caricetea fuscae-Gesellschaft an. Die extensiven und halbintensiven Pflanzengesellschaften entsprechen traditionell bewirtschafteten Wiesen, die eine größere Artenvielfalt und Variation an Vegetationstypen aufweisen als der floristisch triviale Intensivwiesentyp.
This paper focuses on ecological requirements and phytosociological affinity of Avenula adsurgens subsp. adsurgens. Although this grass is widely distributed in central and south-eastern Europe reaching dominance in certain grassland types, the knowledge on its ecology and coenology is very poor. Moreover, some of the published data on its distribution are wrongly related to Avenula praeusta. We studied the taxon within an area of about 300 km2 (Central Slovakia) where it occurs in diverse habitats. Data from a systematic phytosociological survey were used to assess interspecific associations and ecological indicator values of the taxon. Detailed measurements from a transect along a spruce colonisation gradient were used to evaluate its relationship to a set of topographical, microclimatical, pedological and soil-microbiological characteristics. Tillers of A. adsurgens subsp. adsurgens were cultivated for two growing seasons to estimate characteristics of its clonal morphology and growth and its ability of spatial spreading. In the studied area, the taxon occurred mainly over the volcanic bedrock along a wide range of altitudes. It was concentrated in slightly managed or abandoned montane grasslands (800–1100 m) of the Violion caninae and Nardo strictae-Agrostion tenuis alliances. Phytosociologically the taxon seems not to be an important diagnostic species of these communities, rather an indicator of their successional development. Its highest cover was recorded in early to mid-successional stages without significant proportions of woody species. In stands with traditional management by mowing, grazing or their combination, the taxon was common (albeit with lower percentage cover), but more intensive ma-nagement including amelioration or fencing led to its retreat. Ellenberg ecological indicator values of A. adsurgens subsp. adsurgens were set as follows: light 7, temperature 5, continentality 4, moisture 4, soil reaction 5 and nutrients 3. Along a successional gradient, the taxon cover was positively correlated with percentage cover of herb litter, catalase activity, canopy openness and potassium content and negatively correlated with percentage cover of needles and canopy index reflecting the cumulative effects of spruce colonisation. The horizontal spreading of the taxon was enabled by the formation of spacers with a maximum length of 25.5 cm. We suppose that the ability to spread horizontally by spacers, together with the observed clonal plasticity, tall stature and fast growth by intensive tillering, belong to important attributes of A. adsurgens subsp. adsurgens promoting its success and dominant role in the abandoned grasslands.
In Kiefernbeständen des Naturschutzgebietes Mallertshofer Holz wurden, stratifiziert nach Besto-ckungstypen, Vegetationsaufnahmen angefertigt, klassifiziert und mittels Ordination und Zeiger-wertanalyse standörtlich und dynamisch interpretiert. Bei homogenen primären Standortbedingungen folgt die Vegetation einem starken Nährstoffgradienten, bedingt durch unterschiedliche extensive Vornutzungen, Selbstmelioration und Stickstoffeintrag. Für das Management der Wälder ergeben sich daraus drei Optionen: 1. Fortsetzung der selbstgesteuerten Entwicklung eutropher Kiefernforste; 2. aktiver Waldumbau durch Einbringen von Schattbaumarten der potenziellen natürlichen Vegetation; 3. gezielte Auflichtung und Ausmagerung durch starke Eingriffe in Gehölzbestand (Ganzbaumernte) und Bodenvegetation (Beweidung). Der Naturschutzwert des Gebietes kann durch ein Nebeneinander der Varianten 2 und 3 gesichert und optimiert werden.
Cryptogams form a large part of dry grassland plant species richness. As a frequently used tool in grassland restoration, hay transfer is known to transfer cryptogam species. This might result in cryptogam stands differing from those achieved by natural succession. To assess hay transfer as a medium for cryptogam restoration, I analysed species composition of cryptogams in the hay of dry grasslands in Southern Germany, how fast they establish, and how fast they colonize adjacent plots. Cryptogam samples from hay showed species combinations similar to those of the mown sites and large shoot numbers to be present in the hay. Even low-growing and rare species were found in the hay. Hay receptor sites showed larger pleurocarpous moss and fruticose lichen patches than comparable sites without hay transfer, indicating earlier arrival of viable diaspores at the receptor sites. For acrocarpous mosses that colonize new sites by spores, no differences in turf size between succession and restoration plots were found. This shows that species transferred by hay have a distinct advantage over species that have to arrive at newly opened sites by natural means, i.e. many years later. The colonization from small restoration sites into adjacent areas without hay transfer proceeds with moderate speeds of about 1 to 2 m per year, probably with wind drift as the most important dispersal agent. Abundant cryptogam species including most pleurocarpous mosses and some Cladonia species rarely producing spores will be greatly enhanced by hay transfer. Nevertheless, the facilitation of pleurocarpous mosses may be detrimental to acrocarpous moss and epigaeic and saxicolous lichen species diversity, which should be considered in dry grassland restoration. I suggest a combination of different restoration measures in a mosaic pattern to create suitable conditions for a maximum of cryptogam species.
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.