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Land-use intensification is the main factor for the catastrophic decline of insect pollinators. However, land-use intensification includes multiple processes that act across various scales and should affect pollinator guilds differently depending on their ecology. We aimed to reveal how two main pollinator guilds, wild bees and hoverflies, respond to different land-use intensification measures, that is, arable field cover (AFC), landscape heterogeneity (LH), and functional flower composition of local plant communities as a measure of habitat quality. We sampled wild bees and hoverflies on 22 dry grassland sites within a highly intensified landscape (NE Germany) within three campaigns using pan traps. We estimated AFC and LH on consecutive radii (60–3000 m) around the dry grassland sites and estimated the local functional flower composition. Wild bee species richness and abundance was positively affected by LH and negatively by AFC at small scales (140–400 m). In contrast, hoverflies were positively affected by AFC and negatively by LH at larger scales (500–3000 m), where both landscape parameters were negatively correlated to each other. At small spatial scales, though, LH had a positive effect on hoverfly abundance. Functional flower diversity had no positive effect on pollinators, but conspicuous flowers seem to attract abundance of hoverflies. In conclusion, landscape parameters contrarily affect two pollinator guilds at different scales. The correlation of landscape parameters may influence the observed relationships between landscape parameters and pollinators. Hence, effects of land-use intensification seem to be highly landscape-specific., Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe; 1298

Global change has been predominantly studied from the prism of ‘how much' rather than ‘how fast' change occurs. Associated to this, there has been a focus on environmental drivers crossing a critical value and causing so-called regime shifts. This presupposes that the rate at which environmental conditions change is slow enough to allow the ecological entity to remain close to a stable attractor (e.g. an equilibrium). However, environmental change is occurring at unprecedented rates. Equivalently to the classical regime shifts, theory shows that a critical threshold in rates of change can exist, which can cause rate-induced tipping (R-tipping). However, the potential implications of R-tipping in ecology remain understudied. We aim to facilitate the application of R-tipping theory in ecology with the objective of identifying which properties (e.g. level of organisation) increase susceptibility to rates of change. First, we clarify the fundamental difference between tipping caused by the magnitude as opposed to the rate of change crossing a threshold. Then we present examples of R-tipping from the ecological literature and seek the ecological properties related to higher sensitivity to rates of change. Specifically, we consider the role of the level of ecological organisation, spatial processes, eco-evolutionary dynamics and pair–wise interactions in mediating or buffering rate-induced transitions. Finally, we discuss how targeted experiments can investigate the mechanisms associated to increasing rates of change. Ultimately, we seek to highlight the need to better understand how rates of environmental change may induce ecological responses and to facilitate the systematic study of rates of environmental change in the context of current global change.

One of the few laws in ecology is that communities consist of few common and many rare taxa. Functional traits may help to identify the underlying mechanisms of this community pattern, since they correlate with different niche dimensions. However, comprehensive studies are missing that investigate the effects of species mean traits (niche position) and intraspecific trait variability (ITV, niche width) on species abundance. In this study, we investigated fragmented dry grasslands to reveal trait-occurrence relationships in plants at local and regional scales. We predicted that (a) at the local scale, species occurrence is highest for species with intermediate traits, (b) at the regional scale, habitat specialists have a lower species occurrence than generalists, and thus, traits associated with stress-tolerance have a negative effect on species occurrence, and (c) ITV increases species occurrence irrespective of the scale. We measured three plant functional traits (SLA = specific leaf area, LDMC = leaf dry matter content, plant height) at 21 local dry grassland communities (10 m × 10 m) and analyzed the effect of these traits and their variation on species occurrence. At the local scale, mean LDMC had a positive effect on species occurrence, indicating that stress-tolerant species are the most abundant rather than species with intermediate traits (hypothesis 1). We found limited support for lower specialist occurrence at the regional scale (hypothesis 2). Further, ITV of LDMC and plant height had a positive effect on local occurrence supporting hypothesis 3. In contrast, at the regional scale, plants with a higher ITV of plant height were less frequent. We found no evidence that the consideration of phylogenetic relationships in our analyses influenced our findings. In conclusion, both species mean traits (in particular LDMC) and ITV were differently related to species occurrence with respect to spatial scale. Therefore, our study underlines the strong scale-dependency of trait-abundance relationships., Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe; 1151

Einleitung: Transkutane Vakzinierung ist seit einigen Jahren im Fokus tiefergehender Forschung. Die in diesem Zusammenhang vielfach genutzten nadelfreien Impfmethoden erlauben es Probleme, die mit konventioneller Impfung einhergehen, zu umgehen. Gleichzeitig zeigten sich in Versuchen verschiedener Autoren vielversprechende Ergebnisse die immunologische Effektivität betreffend, darunter eine bevorzugte Induktion zellulärer Immunantworten. Es ergaben sich zudem Hinweise darauf, dass Penetrationsförderung und immunaktivierende Effekte wichtige Komponenten für die Entwicklung möglichst effektiver transkutaner Impfsysteme sind. Ob hierzu physikalische, chemische, bzw. biochemische Stimuli geeignet sind, ist bislang wenig bekannt. Methodik: Basierend auf vorangegangenen klinischen Studien mit Verwendung von Vorbehandlungsmethoden der Haut bei transkutaner Impfung, wurden in dieser Arbeit die Effekte physikalischer und chemischer Methoden zur Barriereschädigung in Kombination mit topischer Auftragung eines Influenza-Impfstoffes untersucht. Hierbei wurden drei Schwerpunkte gesetzt: Es wurden hautphysiologische Parameter bestimmt, um das Ausmaß der durch die verwendeten Schädigungsmethoden ausgelösten Barrierestörung zu evaluieren. Weitergehend wurde das reaktive inflammatorische Milieu der Epidermis mit verschiedenen ELISA sowie Array Analysen untersucht. Eine detailliertere Untersuchung durch RT-qPCR wurde für die Methode des Cyanoacrylat Skin Surface Strippings (CSSS) durchgeführt. Abschließend wurde mit Hilfe von histologischen Färbungen sowie unterschiedlichen ELISA der Einfluss der Schädigungsmethoden auf die Penetration des aufgetragenen Impfstoffes untersucht. Ergebnisse: Für die physikalischen Schädigungsmethoden zeigte sich ein geringfügiger Einfluss auf die Hautphysiologie. Die Evaluation verschiedener Inflammationsmarker ergab jedoch Hinweise auf eine durch Tape Stripping erzeugte Stimulation von IL-1alpha, und Array Analysen deuteten auf eine vermehrte Immunreaktion des Gewebes nach Vorbehandlung mit CSSS im Vergleich zu Tape Stripping hin. RT-qPCR wies auf eine vermehrte Genexpression mehrerer pro- inflammatorischer Moleküle nach CSSS und CSSS mit gleichzeitiger Impfstoffauftragung hin. Im Falle der chemischen Schädigungsarten zeigte sich ein milder Effekt auf die Hautphysiologie nach Okklusion von Wasser, ebenso wie von Imiquimod und Hinweise auf starke Störung der Hautbarriere durch 2% SLS unter Okklusion. Okklusion allein, sowie von Imiquimod zeigten einen stimulierenden Effekt auf IL-1alpha. Die Penetration zeigte sich durch Okklusion von SLS gesteigert. Diskussion: Tape Stripping und CSSS zeigten sich als Methoden milder Barriereschädigung, welche trotz lediglich geringer Störung der Hautintegrität die Penetration von topisch appliziertem Impfstoff zu fördern schienen. CSSS zeigte sich darüber hinaus als starker Immunstimulus, welcher eine vielseitige Immunantwort in Kombination mit topischer Impfstoffauftragung auslöste. Alle untersuchten chemischen Schädigungsmethoden zeigten Hinweise auf eine vermehrte Durchlässigkeit der Hautbarriere, wobei SLS eine vergleichsweise sehr starke Schädigung auslöste. Okklusion allein und mit Imiquimod erwiesen sich als immunstimulatorisch und teilweise penetrationsfördernd, was sie vielversprechend für weitere Untersuchungen macht., Introduction: Transcutaneous vaccination strategies have been in the focus of research for several years. Amongst these, needle-free vaccination methods avoid many challenges associated with conventional vaccination. Concomitantly, overall efficacy for various different approaches has been shown by other authors with delivery via the cutaneous route favoring the induction of cellular immune responses. Furthermore, an increase in penetration and immune activation have been discovered to be significant aspects in transcutaneous vaccination. Whether physical, chemical or biochemical stimuli are able to procure this is has not been thoroughly investigated. Methods: Based on clinical studies using skin surface treatment in transcutaneous vaccination this project analysed the effects of physical and chemical skin barrier disruption in combination with topical vaccine application. Firstly, skin-physiological parameters were analysed to determine the degree of barrier disturbance by the disruption methods. Secondly, the inflammatory milieu of the epidermis was investigated with ELISA and Array analyses and a more detailed investigation using RT-qPCR was conducted for Cyanoacrylat Skin Surface Stripping (CSSS). Finally, the influence of skin barrier disruption on the penetration of topically applied vaccine was analysed using histological staining and ELISA. Results: For physical disruption no persistent impairment of the skin physiology was found. The evaluation of different inflammation markers however showed signs of IL-1alpha stimulation after tape stripping, and array analyses indicated increased immune response to CSSS compared to tape stripping. RT-qPCR uncovered an increased gene-expression of various pro-inflammatory molecules after CSSS and CSSS combined with topical vaccine application. In regard to the chemical disruption methods, occlusion of water and imiquimod indicated a mild effect on skin physiology, while more severe disruption was seen after 2 % SLS occlusion. Occlusion with water and imiquimod also showed a stimulating effect on the excretion of IL 1alpha. Penetration was increased following occlusion of SLS Discussion: Tape stripping and CSSS seemed to result in improved penetration of topically applied vaccine despite only causing mild and temporary skin barrier impairment. Furthermore, CSSS has shown itself to be an efficient immune-stimulus, causing a diverse immune response in combination with topical application of vaccine. All investigated chemical methods of skin barrier disruption indicated an increased permeability of the skin barrier, with SLS causing a comparably severe perturbation. Occlusion by itself and in combination with imiquimod has been illustrated to be immune stimulating as well as penetration enhancing, making them promising methods for further investigation.

International audience; The skin plays a crucial role in host defences against microbial attack and the innate cells must provide the immune system with sufficient information to organize these defences. This unique feature makes the skin a promising site for vaccine administration. Although cellular innate immune events during vaccination have been widely studied, initial events remain poorly understood. Our aim is to determine molecular biomarkers of skin innate reaction after intradermal (i.d.) immunization. Using an ex vivo human explant model from healthy donors, we investigated by NanoLC-MS/MS analysis and MALDI-MSI imaging, to detect innate molecular events (lipids, metabolites, proteins) few hours after i.d. administration of seasonal trivalent influenza vaccine (TIV). This multimodel approach allowed to identify early molecules differentially expressed in dermal and epidermal layers at 4 and 18 h after TIV immunization compared with control PBS. In the dermis, the most relevant network of proteins upregulated were related to cell-to-cell signalling and cell trafficking. The molecular signatures detected were associated with chemokines such as CXCL8, a chemoattractant of neutrophils. In the epidermis, the most relevant networks were associated with activation of antigen-presenting cells and related to CXCL10. Our study proposes a novel step-forward approach to identify biomarkers of skin innate reaction. SIGNIFICANCE: To our knowledge, there is no study analyzing innate molecular reaction to vaccines at the site of skin immunization. What is known on skin reaction is based on macroscopic (erythema, redness…), microscopic (epidermal and dermal tissues) and cellular events (inflammatory cell infiltrate). Therefore, we propose a multimodal approach to analyze molecular events at the site of vaccine injection on skin tissue. We identified early molecular networks involved biological functions such cell migration, cell-to-cell interaction and antigen presentation, validated by chemokine expression, in the epidermis and dermis, then could be used as early indicator of success in immunization.