The pseudoscorpion-fauna (Arachnida: Pseudoscorpiones) of a floodplain close to Ingelheim/Rhine, with special reference to the effects of the dry-warm winter 2006/2007

From the beginning of May 2005 to September 2007 the pseudoscorpion fauna in a hardwood floodplain forest of the Rhine valley near Ingelheim was investigated. Altogether 587 individuals representing two species from two families were captured using pitfall traps, trunk eclectors and by litter sieving. The warm, dry winter 2006/2007 exhibited a strong influence upon the activity of Neobisium carcinoides (Hermann, 1804). This winter event was followed by an extreme drought in April 2007, which affected the activity maximum of the corticolous species Chernes hahnii (C.L. Koch, 1839). In 2005 and 2006 the activity maximum of C. hahnii was observed in July, whereas in 2007 maturity was achieved earlier in May. Furthermore 31 individuals of N. carcinoides were captured in trunk eclectors. This climbing behaviour correlates with the presence of Lepidocyrtus lignorum (Collembola: Entomobryidae) on the trunks. Keywords: activity, Collembola, drought, false scorpions, Germany, prey captur

Evaluierung von Möglichkeiten zur biologischen Kontrolle der Reblaus durch den entomophagen Pilz Metarhizium anisopliae im ökologischen Weinbau

Seit einigen Jahren werden weltweit erneut Rückgangserscheinungen in Rebanlagen beobachtet, die auf Reblausbefall zurückgeführt werden. Reblausbefall an Wurzeln von Unterlagsreben kann zu vorzeitigem Blattfall, reduziertem Triebwachstum, Ertrags- und Qualitätsverlusten bis hin zum Absterben der Rebstöcke führen. Derzeit sind keine chemischen oder biologischen Pflanzenschutzmittel zur Reblauskontrolle verfügbar. Allerdings wurden in den letzten Jahren erhebliche Fortschritte bei der Entwicklung biologischer Schädlingskontrollorganismen erzielt. Innerhalb dieses Projektes wurden in einem Freilandversuch auf einer organisch bewirtschafteten Versuchsfläche die Effektivität, die Bodenpersistenz und die Einflüsse auf Non-target-Organismen von Metarhizium anisopliae untersucht. Hierbei wurden die mit Metarhizium behandelte Versuchsparzellen mit unbehandel-ten bzw. mit steriler Gerste behandelten Parzellen verglichen. Die Befallshäufigkeit (Porten & Huber 2003) der Rebstöcke mit Reblaus war dabei auf den mit Metarhizium behandelten Parzellen im Bereich der Fahrgasse signifikant geringer. Auch die Befallsintensität war signifikant reduziert. Zwei Monate nach der Applikation wurden für eine biologische Schädlingsbekämpfung ausreichende Dichten im Bereich der Fahrgasse festgestellt. Fünf Monate nach der Applikation wurden erhöhte Metarhizium-Dichten auch im Unterstockbereich auf den behandelten Parzellen gemessen. Bei den durchgeführten Non-target-Untersuchungen konnten im Versuchsvarianten-vergleich keine signifikanten Änderungen der Abundanz oder der Diversität bei Bodeninvertebraten (Ordungen Edaphon gesamt, Collembolen-, Carabiden- und Regenwurmarten) festgestellt werden. Auch bei den untersuchten konspezifischen Pilzzönosen wurden keine signifikanten Unterschiede zwischen den Versuchsvarianten festgestellt. Bei den oenologische Begeituntersuchungen (Ertrag, Beerengewicht, °BRIX, Most-pH) zeigten sich ebenfalls keine Unterschiede zwischen den untersuchten Versuchsvarianten

Um novo método para simular o estado hidrológico do solo em condições naturais

Micro, macro and mesofauna in the soil often respond to fluctuating environmental conditions, resulting in changes of abundance and community structure. Effects of changing soil parameters are normally determined with samples taken in the field and brought to the laboratory, i.e. where natural environmental conditions may not apply. We devised a method (STAFD – soil tubes for artificial flood and drought), which simulates the hydrological state of soil in situ using implanted cores. Control tubes were compared with treatment tubes in which floods of 15, 30, 60 and 90 days, and droughts of 60, 90 and 120 days were simulated in the field. Flooding and drought were found to reduce number of individuals in all soil faunal groups, but the response to drought was slower and not in proportion to the expected decrease of the water content. The results of the simulated floods in particular show the value of the STAFD method for the investigation of such extreme events in natural habitats.As micro, macro e mesofaunas no solo respondem frequentemente à variação das condições ambientais, o que resulta em alterações na abundância e na estrutura da comunidade. Os efeitos das alterações nos parâmetros do solo são normalmente determinados com amostras recolhidas no campo e trazidas ao laboratório, ou seja, onde as condições ambientais naturais podem não ser aplicáveis. Criamos um método (STAFD – tubos de amostra de solo para inundações e secas artificiais), que simula o estado hidrológico do solo in situ com núcleos implantados. As amostras de controle foram comparadas com amostras de tratamentos em que foram simuladas inundações de 15, 30, 60 e 90 dias e secas de 60, 90 e 120 dias no campo. Verificou-se que as inundações e a seca reduziram a quantidade de individuos em todos os grupos de fauna de solo, mas a resposta à seca foi mais lenta e não proporcional à redução prevista no teor de água. Os resultados das inundações simuladas demonstram, em especial, o valor do método STAFD para a investigação desse tipo de eventos extremos nos habitats naturais

Respostas e adaptações de comunidades de colêmbolos (Hexapoda: Collembola) a condições de inundação e hipoxia

Standard ecological methods (pitfall traps, trunk eclectors and soil cores) were used to evaluate collembolan community responses to different flooding intensities. Three sites of a floodplain habitat near Mainz, Germany, with different flooding regimes were investigated. The structures of collembolan communities are markedly different depending on flooding intensity. Sites more affected by flooding are dominated by hygrophilic and hygrotolerant species, whereas the hardwood floodplain is dominated by mesophilic species. The survival strategies of the hygrophilic and hygrotolerant species include egg diapause and passive drifting. The physiological adaptations to hypoxic conditions of several collembolan species were analyzed using a microcalorimeter. The activities were tested under normoxic and hypoxic/anoxic conditions as well as during post-hypoxic recovery. Lactate was increased after hypoxic intervals in the species studied, suggesting that, in addition to a massive decrease in metabolic rate, a modest glycolytic activity may be involved in the tolerance to hypoxia.Foram utilizados os métodos ecológicos padrão (armadilhas "pitfall", armadilhas de tronco e amostras de solo) para avaliar as respostas de comunidade de colêmbolos a diferentes intensidades de inundação. Foram investigados três locais de um habitat de leitos de inundação perto de Mainz, Alemanha, com diferentes regimes de inundação. As estruturas das comunidades de colêmbolos foram nitidamente diferentes conforme a intensidade das inundações. Nos locais mais afetados por inundações, as espécies higrofílicas e higrotolerantes dominaram, ao passo que as espécies mesofílicas foram dominantes nos locais de leitos de inundação com angiospermas. As estratégias de sobrevivência das espécies higrofílicas e higrotolerantes incluem a diapausa dos ovos e o deslocamento passivo. Foi testada a adaptação fisiológica a condições hipóxicas de espécies selecionadas de colêmbolos através de análises por microcalorimetria. A atividade das espécies foi testada em condições normóxicas e hipóxicas/anóxicas e durante a recuperação pós-hipoxia. Verificou-se que o lactato aumentava após condições hipóxicas nas espécies avaliadas, o que sugere que, além de um decréscimo massivo na atividade metabólica, deve haver também certa atividade glicolítica associada à tolerância à hipoxia

Effects of ecological flooding on the temporal and spatial dynamics of carabid beetles (Coleoptera, Carabidae) and springtails (Collembola) in a polder habitat

Within the scope of the Integrated Rhine Program an ecological flood gate and channel was inserted into the polder “Ingelheim” to enhance animal and plant diversity. In 2008, carabid beetles and springtails were collected, using pitfall traps, to measure the effects of ecological flooding and a strong precipitation event at a flood-disturbed and a dry location in this area. At both localities, xerophilic and mesophilic carabid beetle species were dominant throughout the study period. The total number of individuals of hygrophilic species was comparatively constant, while species number increased, partly due to the changed moisture conditions caused by ecological flooding and strong precipitation. Carabid beetle diversity and evenness decreased marginally when ecological flooding was absent. Springtails represent a less mobile arthropod order, and as such the impact of ecological flooding was stronger. An increase in both numbers of species and individuals of hygrophilic and hygrotolerant species occurred in the flood-disturbed location after ecological flooding. After the sites at both locations had dried, the number of individuals belonging to these species declined rapidly. In contrast to carabid species, the strong precipitation event showed no influence on hygrophilic springtail species. Thus, collembolan diversity and evenness decreased markedly in the absence of flooding. We showed that ecological flooding has an influence on the spatial and temporal dynamics of different arthropod groups that inhabit the polder “Ingelheim”. These findings demonstrate the importance of using different arthropod groups as bioindicators in determining the ecological value of a particular polder design