@article{UphusLuepkeYuanetal.2021, author = {Uphus, Lars and L{\"u}pke, Marvin and Yuan, Ye and Benjamin, Caryl and Englmeier, Jana and Fricke, Ute and Ganuza, Cristina and Schwindl, Michael and Uhler, Johannes and Menzel, Annette}, title = {Climate effects on vertical forest phenology of Fagus sylvatica L., sensed by Sentinel-2, time lapse camera, and visual ground observations}, series = {Remote Sensing}, volume = {13}, journal = {Remote Sensing}, number = {19}, issn = {2072-4292}, doi = {10.3390/rs13193982}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-248419}, year = {2021}, abstract = {Contemporary climate change leads to earlier spring phenological events in Europe. In forests, in which overstory strongly regulates the microclimate beneath, it is not clear if further change equally shifts the timing of leaf unfolding for the over- and understory of main deciduous forest species, such as Fagus sylvatica L. (European beech). Furthermore, it is not known yet how this vertical phenological (mis)match — the phenological difference between overstory and understory — affects the remotely sensed satellite signal. To investigate this, we disentangled the start of season (SOS) of overstory F.sylvatica foliage from understory F. sylvatica foliage in forests, within nine quadrants of 5.8 × 5.8 km, stratified over a temperature gradient of 2.5 °C in Bavaria, southeast Germany, in the spring seasons of 2019 and 2020 using time lapse cameras and visual ground observations. We explained SOS dates and vertical phenological (mis)match by canopy temperature and compared these to Sentinel-2 derived SOS in response to canopy temperature. We found that overstory SOS advanced with higher mean April canopy temperature (visual ground observations: -2.86 days per °C; cameras: -2.57 days per °C). However, understory SOS was not significantly affected by canopy temperature. This led to an increase of vertical phenological mismatch with increased canopy temperature (visual ground observations: +3.90 days per °C; cameras: +2.52 days per °C). These results matched Sentinel-2-derived SOS responses, as pixels of higher canopy height advanced more by increased canopy temperature than pixels of lower canopy height. The results may indicate that, with further climate change, spring phenology of F. sylvatica overstory will advance more than F. sylvatica understory, leading to increased vertical phenological mismatch in temperate deciduous forests. This may have major ecological effects, but also methodological consequences for the field of remote sensing, as what the signal senses highly depends on the pixel mean canopy height and the vertical (mis)match.}, language = {en} } @phdthesis{Hsieh2011, author = {Hsieh, Samuel Yu-Lung}, title = {The diversity and ecology of the spider communities of European beech canopy}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-66966}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {Ein wesentliches Ziel {\"o}kologischer Forschung ist es, die Frage zu beantworten, wie Arten koexistieren k{\"o}nnen und die biologische Vielfalt erhalten bleibt. Um zu verstehen, wie dabei Gemeinschaften in unterschiedlichen r{\"a}umlich-zeitlichen Dimensionen interagieren, um die biologische Vielfalt zu erhalten, ist ein umfassendes prozessorientiertes Wissen erforderlich. Demzufolge konzentrierte sich meine Studie im Wesentlichen auf die Biodiversit{\"a}t und die sie beeinflussenden raum-zeitlichen {\"o}kologischen Prozesse. Vergleicht man die {\"A}hnlich- bzw. Un{\"a}hnlichkeit der in verschieden alten Best{\"a}nden lebenden Spinnengemeinschaften der Buchen (Fagus sylvatica L.), dann zeigt sich, dass die {\"a}lteste Baumkohorte offensichtlich einzigartige Ressourcen besitzt, welche die Zusammensetzung der Spinnengemeinschaften deutlich pr{\"a}gen. {\"U}ber das Jahr hin zeigten die Spinnengemeinschaften trotz der jahreszeitlich unterschiedlich {\"o}kologischen Randbedingungen eine sich wiederholende, vorhersehbare Dynamik. Der Vergleich {\"u}ber die Jahre ergab, dass das "Neutrale Modell" und das "Nischen-Modell" gleichzeitig funktionieren k{\"o}nnen. Beide sind notwendig, um die Dynamik der in den Buchenkronen der verschiedenen Altersklassen lebenden Spinnengemeinschaften vollst{\"a}ndig erkl{\"a}ren zu k{\"o}nnen.}, subject = {Spinnen}, language = {en} } @article{HsiehLinsenmair2012, author = {Hsieh, Yu-Lung and Linsenmair, Karl Eduard}, title = {Seasonal dynamics of arboreal spider diversity in a temperate forest}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-75158}, year = {2012}, abstract = {Measuring and estimating biodiversity patterns is a fundamental task of the scientist working to support conservation and informmanagement decisions.Most biodiversity studies in temperate regions were often carried out over a very short period of time (e.g., a single season) and it is often—at least tacitly—assumed that these short-termfindings are representative of long-termgeneral patterns.However, should the studied biodiversity pattern in fact contain significant temporal dynamics, perhaps leading to contradictory conclusions. Here, we studied the seasonal diversity dynamics of arboreal spider communities dwelling in 216 European beeches (Fagus sylvatica L.) to assess the spider community composition in the following seasons: two cold seasons (I:November 2005-January 2006; II: February-April) and two warm seasons (III: May-July; IV: August-October). We show that the usually measured diversity of the warmseason community (IV: 58 estimated species) alone did not deliver a reliable image of the overall diversity present in these trees, and therefore, we recommend it should not be used for sampling protocols aimed at providing a full picture of a forest's biodiversity in the temperate zones. In particular, when the additional samplings of other seasons (I, II, III) were included, the estimated species richness nearly doubled (108). Community I possessed the lowest diversity and evenness due to the harsh winter conditions: this community was comprised of one dominant species together with several species low in abundance. Similarity was lowest (38.6\%) between seasonal communities I and III, indicating a significant species turnover due to recolonization, so that community III had the highest diversity. Finally, using nonparametric estimators, we found that further sampling in late winter (February-April) is most needed to complete our inventory. Our study clearly demonstrates that seasonal dynamics of communities should be taken into account when studying biodiversity patterns of spiders, and probably forest arthropods in general.}, subject = {Biologie}, language = {en} }