Please use this identifier to cite or link to this item: http://dx.doi.org/10.14279/depositonce-1951
Main Title: Climate Change and Biodiversity in Temperate Montane Forests - Patterns, Processes and Predictions
Translated Title: Klimawandel und Biodiversität in gemäßigten montanen Wäldern - Muster, Prozesse and Vorhersagen
Author(s): Bässler, Claus
Advisor(s): Dziock, Frank
Granting Institution: Technische Universität Berlin, Fakultät VI - Planen Bauen Umwelt
Type: Doctoral Thesis
Language: English
Language Code: en
Abstract: In einem ersten Schritt wurde die Temperaturentwicklung im Untersuchungsgebiet (Innerer Bayerischer Wald) analysiert, um physikalische Veränderungen auf lokaler Ebene quantifizieren zu können. Es wurde ein deutliches Erwärmungssignal für alle Höhenstufen detektiert. Mit Hilfe von Korrespondenzanalysen konnte der Faktor Höhe als wichtigstes Steuerelement für eine Vielzahl taxonomischer Gruppen identifiziert werden. Die Bruchpunktanalyse bestätigt für die Gefäßpflanzen bei ca. 1150m üNN eine deutliche Veränderung in der Zusammensetzung der Artengemeinschaften (diskrete Verteilung). Der enge Zusammenhang zwischen Höhe und Temperatur qualifizieren diese Höhenstufe als klimasensitive Zone für weitere Monitoringaktivitäten. Weiterhin wurden die relativen Einflüsse von Klima, Waldstrukturen und Habitattradition auf strukturgebundene Artengruppen am Beispiel Holzbewohnender Pilze entlang des Höhengradienten untersucht. Wichtigste Steuergrößen für die Artengemeinschaften, Artendichte und Anzahl der Registrierungen sind Faktoren der Waldstruktur, welche die des Klimas weit überlagern. Habitattradition ist nur entscheidend für die Zielgruppe der bedrohten Arten. Es konnte weiterhin nachgewiesen werden, dass die Molluskenartendichte und die Dichte einzelner Mollusken mit zunehmender Höhe nicht linear abnehmen. Der Bruch dieser Veränderung findet ebenfalls in der Höhenstufe 1100-1200m üNN statt. Das Alter der Habitate ist der überragende Faktor, welcher die Dichte vieler Arten beeinflusst. Allerdings kann ebenfalls festegestellt werden, dass die globale Erwärmung zu einem Anstieg der Artendichte führen wird. Schließlich erfolgte die Modellierung ausgewählter Hochlagenarten unterschiedlicher taxonomischer Gruppen auf der Basis von zwei Klimaszenarien zur Abschätzung des Extinktionsrisikos. Es konnte ein erhöhtes Aussterberisiko der Zielarten für den Nationalpark Bayerischer Wald vorhergesagt werden, wenn es zur weiteren Erwärmung kommt. Durch ähnliche Arten-Umweltbeziehungen besteht für die meisten ausgewählten Arten eine sehr gute artenübergreifende Indikatoreignung zur Feststellung frühzeitiger Veränderungen durch globale Erwärmung. Eine grobe Abschätzung zeigt Aussterberaten von 1.5 - 23.4% für die Arten der hochmontanen Lagen. Rote Liste Arten sind nach dieser Abschätzung überproportional betroffen (Extinktionsrisiko von 3.3 - 75%).
The first aim of this study is to analyse the trend of air temperature for the study area based on data from selected meteorological stations and to reveal regional patterns of climate change. Predominantly positive trends were noticeable for the period under consideration. Thus, consequences are expected for biological systems on a regional scale. I attempted to obtain deeper insights on the meaning of the complex factor altitude and its influence on distribution patterns. To this end, vascular plant community compositions were studied, to assess the influence of altitude among other habitat predictors as well as the character of revealed changes. The ordination confirms that altitude is the best explanatory variable, even when other habitat predictors are considered. The identification of a threshold at 1142m a.s.l. using maximally selected rank statistics indicates discrete changes in vascular plant community composition along the altitudinal gradient. Due to the strong correlation of altitude and temperature, this elevation is considered to represent a climate sensitive zone for further climate change monitoring. To solve the problem of strong co-variation of abiotic and structural factors along the altitudinal gradient and to reveal the contribution of these confounding effects, a further objective is to determine the relative influence of climate, forest structure and habitat continuity on wood-inhabiting fungi. The combined effect of forest structure variables was clearly more important than the set of climate variables in its effect on community composition, species density and species records. Only for threatened species was habitat continuity shown to be an important factor. With a similar intention, we also assessed the influence of the regional temperature gradient with altitude on molluscs. An additional objective here was to test the influence of site-specific habitat factors by considering several habitat variables ranging from stand age to plant species richness. We found that density of individuals and species decreased non-linearly with altitude. The slope of this decrease changed between 1100 and 1200 m a.s.l. Spatial generalized linear models showed that especially habitat age is an important predictor for the density of many species, but that global warming should lead to an overall increase in species density. To assess the regional risk of extinction and to identify appropriate indicators for climate change monitoring, the final immediate objective is to model the occurrence, under two global warming scenarios, of six high montane species selected. The suitability of these high montane species for climate change monitoring as cross-taxon indicators is then evaluated. The similar species-environmental relationships shared by many high montane species lead to the conclusion, that their cross-taxon suitability as indicators of early signs of global warming is high where the model discrimination is of high quality. The choice of which indicator to use should be determined mainly by the type of monitoring systems which are already employed in a region. As a rough assessment and prospect for the future, from 1.5 - 23.4 % of the target taxa may become extinct in the study area as a result of climate change. Red listed species are disproportionally sensitive, with an extinction risk of 3.3 % - 75.0%. One main conclusion is that the regionally different effects of climate change make it necessary to intensify research on indications of change, indicators for these and extinction risk. To achieve this, continued and expanded climate change research and monitoring are necessary. To summarize: Altitude was revealed as the main driver, with similar patterns of occurrence along the gradient for different taxonomic groups, distributed non-linearly and changing abruptly at approximately 1100-1200m a.s.l. However, it was revealed that not all taxonomic groups affected by altitude are primarily driven by climate. Sensitivity to climate change and usefulness for indication of climate sensitive zones was detected for vascular plant community compositions, which are expected to be affected directly by global warming. Mapping repeated in a few years could reveal displaced thresholds. Further studies are also necessary which will prove shifts in distribution at the species level (where do species reach their lower and upper limits) in the detected climate sensitive zones. As clear indicators, the high montane species here studied (with one exception) seem to be well suited for monitoring of climate change, and possess cross-taxon capability. Their use in monitoring should be implemented as soon as possible, to achieve rapid and unequivocal proof of effects of climate change in the Central European montane zones.
URI: urn:nbn:de:kobv:83-opus-19598
http://depositonce.tu-berlin.de/handle/11303/2248
http://dx.doi.org/10.14279/depositonce-1951
Exam Date: 18-Jul-2008
Issue Date: 28-Aug-2008
Date Available: 28-Aug-2008
DDC Class: 500 Naturwissenschaften und Mathematik
Subject(s): Aussterberisiko
Biodiversität
Indikatoren
Klimawandel
Mittelgebirge
Biodiversity
Climate Change
Extinction risc
Indicators
Low Mountain Range
Usage rights: Terms of German Copyright Law
Appears in Collections:Institut für Ökologie » Publications

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