580 Pflanzen (Botanik)
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Sorbus cordigastensis N. Mey. (Kordigast-Mehlbeere) ist eine Rote-Liste-Art aus dem Komplex hybridogener Sippen von Sorbus aria und S. torminalis, die endemisch am Kordigast, einem Zeugenberg des Oberen Jura in der Weismainalb (Naturraum „Nördliche Fränkische Alb“) vorkommt. Ziel der Untersuchung war es, die Verbreitung und Größe der Population sowie den Zustand ihrer Verjüngung zu erfassen. Zu diesem Zweck wurden sämtliche im Gebiet vorkommenden Individuen mit einer Wuchshöhe über 1,3 m punktgenau kartiert. In drei etwa 0,35–0,4 ha großen Waldbeständen wurden mittels Stichprobenverfahren die Anzahl und Wuchshöhe der Jungpflanzen sowie das Ausmaß der Wildschäden ermittelt. Sorbus cordigastensis ist mit etwa einem größeren (> 1,3 m hoch) Individuum pro Hektar im untersuchten Gebiet selten, kommt aber lokal und insbesondere an Waldrändern gehäuft vor. In Beständen mit fruktifizierenden Altbäumen verjüngt sich die Art gut. In den drei untersuchten Waldbeständen konnten, bezogen auf einen Hektar Fläche, im Durchschnitt etwa 1500 Jungpflanzen mit einer Wuchshöhe < 1,3 m nachgewiesen werden. Der Großteil davon ist weniger als 30 cm hoch, Jungpflanzen über 90 cm Höhe fehlen jedoch. Eine der Ursachen dafür sind starke Wildschäden. Bei zwei Drittel aller Jungpflanzen ist der Leittrieb ein- oder mehrmals verbissen. Verschiedene Beobachtungen weisen darauf hin, dass darüber hinaus Lichtmangel in den relativ dichten Beständen die dauerhafte Etablierung der Verjüngung beeinträchtigt. Die Population der Kordigast-Mehlbeere ist derzeit an ihrem Naturstandort noch relativ groß und gut zur Reproduktion fähig. Da sich ihre Verjüngung aber nicht ausreichend etablieren kann, ist der Bestand auf längere Sicht vom Aussterben bedroht. Schutzmaßnahmen müssen darauf abzielen, die Bedingungen für das Aufwachsen der Verjüngung durch Verringerung der Wildschäden und Auflichtung der Bestände zu verbessern.
Wrack burial reduces germination and establishment of the invasive cordgrass Spartina densiflora
(2014)
Germination and emergence of halophytes may decrease significantly by seed burial in dead plant material, or wrack, which is common and abundant in tidal marshes. The effects of plant debris (wrack) burial on seed germination and seedling establishment of Spartina densiflora, an invasive cordgrass, were studied under greenhouse conditions and compared with field observations. Five wrack burial depths were applied: control without wrack, 1 cm (1235 ± 92 g DW wrack m-2), 2 cm (3266 ± 13 g DW m-2), 4 cm (4213 ± 277 g DW m-2), and 8 cm (6138 ± 227 g DW m-2). Sediment pH, electrical conductivity, redox potential and temperature were recorded. Quiescence increased with wrack load up to ~20% at 8 cm deep. Germination decreased with wrack load from 96% to 14%, which could be related with anoxic conditions under the debris since sediment redox potential was as low as -83 ± 7 mV at 8 cm. Germination percentage increased and quiescent and dormant percentages decreased at higher daily sediment temperatures and with higher daily temperature fluctuations, conditions that were recorded without or under low loads of wrack. Spartina densiflora did not show primary dormancy, but its seeds entered into a non-deep physiological dormancy below 1 cm deep in plant debris. The establishment of S. densiflora seedlings was also greatly reduced by wrack burial since only 6 seedlings (11 ± 5 % of germinated seeds) emerged above plant debris from 1 cm and all seedlings died from deeper than 1 cm. S. densiflora seedling development was also reduced by wrack burial. The inverse relationship between germination and emergence of S. densiflora with wrack burial recorded in our study is useful to predict its invasion dynamics and to plan the management of invaded marshes.
Medicinal plants represent a big reservoir for discovering new drugs against all kinds of diseases including inflammation. In spite the large number of promising anti-inflammatory plant extracts and isolated components, research on medicinal plants proves to be very difficult. Based on that background this review aims to provide a summarized insight into the hitherto known pharmacologically active concentrations, bioavailability, and clinical efficacy of boswellic acids, curcumin, quercetin and resveratrol. These examples have in common that the achieved plasma concentrations were found to be often far below the determined IC50 values in vitro. On the other hand demonstrated therapeutic effects suggest a necessity of rethinking our pharmacokinetic understanding. In this light this review discusses the value of plasma levels as pharmacokinetic surrogates in comparison to the more informative value of tissue concentrations. Furthermore the need for new methodological approaches is addressed like the application of combinatorial approaches for identifying and pharmacokinetic investigations of active multi-components. Also the physiological relevance of exemplary in vitro assays and absorption studies in cell-line based models is discussed. All these topics should be ideally considered to avoid inaccurate predictions for the efficacy of herbal components in vivo and to unlock the “black box” of herbal mixtures.
Anhand eines Datensatzes von 1.708 Vegetationsaufnahmen aus 154 bayerischen Naturwaldreservaten wurde die realisierte ökologische Nische von 25 Baumarten hinsichtlich Lichtbedarf bzw. Schattentoleranz untersucht. Für jede Baumart wurde die Stetigkeit des Vorkommens in Baumschicht und Verjüngung berechnet. Für jede Aufnahme wurde die dem Bestandesunterwuchs zur Verfügung stehende Lichtmenge durch Berechnung des mittleren ungewichteten Licht-Zeigerwertes (mL) aller vorkommenden Arten (ohne Baumschicht) auf einer Relativskala geschätzt. Für jede 0,5-Einheiten-Stufe von mL wurde die Präferenz jeder Baumart, getrennt nach Baum- (> 5m) und Verjüngungsschicht (< 5m), als Differenz zwischen relativer Häufigkeit der jeweiligen Art und der relativen Häufigkeit aller Aufnahmen in der mL-Stufe im gesamten Datensatz berechnet. Die Präferenzprofile von Baumschicht und Verjüngungsschicht bildeten die Grundlage einer numerischen Klassifikation von 6 lichtökologischen Nischen typen. Diese Typen werden hinsichtlich ihrer Bindung an bestimmte Entwicklungsphasen und Strukturen der natürlichen Walddynamik diskutiert, mit geläufigen Einteilungen der Baumarten verglichen und im Hinblick auf eine Prognose des Verhaltens unter sich ändernden Umweltbedingungen ausgewertet. – Während sich Edellaubbäume des Tilio-Acerion in den Reservaten sehr ähnlich wie Fagus und Abies verhalten, bilden die Baumarten der Eichenmischwälder eine lichtökologische Gruppe mit rückläufiger Verjüngungstendenz. Unter den übrigen Halbschattbaumarten hebt sich eine Gruppe heraus, welche sich in geschlossenen Beständen vorausverjüngt und nach Störung in die Baumschicht vordringt. Pionierbaumarten bleiben in Naturwaldreservaten weitestgehend auf Sonderstandorte, wo ihre Verjüngung viel Licht vorfindet, beschränkt.
Anhand eines Datensatzes von 1.708 Vegetationsaufnahmen aus 154 bayerischen Naturwaldreservaten wurde die realisierte ökologische Nische von 25 Baumarten hinsichtlich Lichtbedarf bzw. Schattentoleranz untersucht. Für jede Baumart wurde die Stetigkeit des Vorkommens in Baumschicht und Verjüngung berechnet. Für jede Aufnahme wurde die dem Bestandesunterwuchs zur Verfügung stehende Lichtmenge durch Berechnung des mittleren ungewichteten Licht-Zeigerwertes (mL) aller vorkommenden Arten (ohne Baumschicht) auf einer Relativskala geschätzt. Für jede 0,5-Einheiten-Stufe von mL wurde die Präferenz jeder Baumart, getrennt nach Baum- (> 5m) und Verjüngungsschicht (< 5m), als Differenz zwischen relativer Häufigkeit der jeweiligen Art und der relativen Häufigkeit aller Aufnahmen in der mL-Stufe im gesamten Datensatz berechnet. Die Präferenzprofile von Baumschicht und Verjüngungsschicht bildeten die Grundlage einer numerischen Klassifikation von 6 lichtökologischen Nischentypen. Diese Typen werden hinsichtlich ihrer Bindung an bestimmte Entwicklungsphasen und Strukturen der natürlichen Walddynamik diskutiert, mit geläufigen Einteilungen der Baumarten verglichen und im Hinblick auf eine Prognose des Verhaltens unter sich ändernden Umweltbedingungen ausgewertet. - Während sich Edellaubbäume des Tilio-Acerion in den Reservaten sehr ähnlich wie Fagus und Abies verhalten, bilden die Baumarten der Eichenmischwälder eine lichtökologische Gruppe mit rückläufiger Verjüngungstendenz. Unter den übrigen Halbschattbaumarten hebt sich eine Gruppe heraus, welche sich in geschlossenen Beständen vorausverjüngt und nach Störung in die Baumschicht vordringt. Pionierbaumarten bleiben in Naturwaldreservaten weitestgehend auf Sonderstandorte, wo ihre Verjüngung viel Licht vorfindet, beschränkt.
Seed dispersal is a key ecosystem function for plant regeneration, as it involves the movement of seeds away from the parental plants to particular habitats where they can germinate and transition to seedlings and ultimately adult plants. Seed dispersal is shaped by a diversity of abiotic and biotic factors, particularly by associations between plants and climate and between plants and other species. Due to the ongoing loss of biodiversity and changing global conditions, such interactions are prone to change and pose a severe threat to plant regeneration. One way to address this challenge is to study associations between plant traits and abiotic and biotic factors to understand the potential impacts of global change on plant regeneration. Plant communities have long been analyzed through the lens of vegetative traits, mainly ignoring how other traits interact and respond to the environment. For instance, while associations between vegetative traits (e.g., specific leaf area, leaf nitrogen content) and climate are well studied, there are few case studies of reproductive traits in relation to trait-environment associations in the context of global change.
Thus, the overarching aim of this dissertation is to explore how trait-environment associations, with a special focus on reproductive traits, can improve our understanding of the effect that global change may have on seed dispersal, and ultimately on plant regeneration. To this end, my research focuses on studying associations between plant traits and abiotic and biotic factors along an elevational gradient in both forests and deforested areas of tropical mountains. This dissertation addresses three principal research objectives.
First, I investigate the extent to which reproductive (seed and fruit traits) and vegetative traits (leaf traits) are related to abiotic and biotic factors for communities of fleshy-fruited plants in the Ecuadorian Andes. I used multivariate analyses to test associations between four (a)biotic factors and seven reproductive traits and five vegetative traits measured on 18 and 33 fleshy fruited plant species respectively. My analyses demonstrate that climate and soil conditions are strongly associated with the distribution of both reproductive and vegetative traits in tropical tree communities. The production of “costly” vs. “cheap” seeds, fruits and leaves, i.e., the production of few rewarding fruits and acquisitive leaves versus the production of many less-rewarding fruits and conservative leaves, is primarily limited by temperature, whereas the size of plant organs is more related to variation in precipitation and soil conditions. My findings suggest that associations between reproductive and vegetative traits and the abiotic environment follow similar principles in tropical tree communities.
Second, I assess how climate and microhabitat conditions affect the prevalence of endozoochorous plant species in the seed rain of tropical montane forests in southern Ecuador. I analyzed seed rain data for an entire year from 162 traps located across an elevational gradient spanning of 2000 m. I documented the microhabitat conditions (leaf area index and soil moisture next to each seed trap) at small spatial scale as well as the climatic conditions (mean annual temperature and rainfall in each plot) at large spatial scale. After a one-year of sampling, I counted 331,838 seeds of 323 species/morphospecies. My analyses demonstrate that the prevalence of endozoochorous plant species in the seed rain increases with temperature across elevations and with leaf area index within elevations. These results show that the prevalence of endozoochory is shaped by the interplay of both abiotic and biotic factors at large and small spatial scales.
Third, I examine the potential of seed rain to restore deforested tropical areas along an elevational gradient in southern Ecuador. For this chapter, I collected seed rain using 324 seed traps installed in 18 1-ha plots in forests (nine forest plots) and in pastures (nine deforested plots) along an elevational gradient of 2000 m. After a sampling period of three months, I collected a total of 123,039 seeds of 255 species/morphospecies from both forests and pastures along the elevational gradient. I did not find a consistent decrease in the amount and richness of seed rain between forests and pastures, but I detected a systematic change in the type of dispersed seeds, as heavier seeds and a higher proportion of endozoochorous species were found in forests compared to pastures at all elevations. This finding suggests that deforestation acts as a strong filter selecting seed traits that are vital for plant regeneration.
Understanding the role that trait-environment associations play in how plant communities regenerate today could serve as a basis for predicting changes in regeneration processes of plant communities under changing global conditions in the near future. Here, I show how informative the measurement of reproductive traits and trait environment associations are in facilitating the conservation of forest habitats and the restoration of deforested areas in the context of global change.
Zwischen dem Nordrand der Mittelgebirge und den nordwestdeutschen Altmoränengebieten liegt eine bis 30 km breite Lößzone, die als altbesiedeltes Gebiet eine stark ausgeräumte Kulturlandschaft darstellt. Die Restflächen der Wälder betragen nur noch 5%, zeigen aber eine breite Amplitude verschiedener Waldgesellschaften. In den eigentlichen Lößbereichen wachsen vor allem Eichen-Hainbuchenwälder verschiedener Ausprägung von sehr artenarmen bis zu artenreichen Beständen. Sie gehören zum Stellario-Carpinetum Oberd. 1957, das sich in 2 Subass.-Gruppen mit 4 Subassoziationen und mehrere Varianten gliedern lässt. Einige Wälder nasser Standorte lassen sich dem Alno-Ulmion zuordnen.
Rare species have long exerted a particular fascination for many botanists. The reasons for this are discussed, as are the justifications for the scientific study of rare and threatened species. A high proportion of the threatened species currently on the Schedules of threatened species in New South Wales were first collected by the earliest botanical explorers. Possible reasons for their success in finding rare species are speculated upon.
Legislative requirements for the identification of threatened species have arisen under the Biodiversity Convention, and the particular regime established by the New South Wales Threatened Species Conservation Act 1995 is described. Features of the plants currently included on the New South Wales Schedules are discussed and the question as to whether they are affected by a variety of recording biases is examined. The consequences of listing for the long term conservation of threatened species are explored.
Australian subtropical rainforests and plant populations have become increasingly fragmented since European settlement. Managing relict populations and remnants within the landscape matrix is dependent upon our understanding of plant reproductive biology. The incidence of autogamous self-compatibility and dioecy was investigated in subtropical rainforests, near Taree, in the Manning Valley (northern New South Wales). The proportion of dioecious species in rainforests of the region is high (~17%), but varies among sites. The potential for hermaphroditic species to self-pollinate was examined by bagging inflorescences in the field. Of the > 30 species (in 14 families) studied, nine species exhibited high levels of selfcompatibility. These were predominantly pioneer and edge species, but other pioneer species were self-incompatible. Different behaviour occurred within families. Twenty species (in 13 families) regenerated from basal coppice or root suckers following bushfire. The significance of knowledge of reproductive biology for management is discussed.
Classifying and mapping landscapes are tools to simplify complex systems into the discreet subsets widely used in landscape management. In 1999, the Queensland Government adopted a Regional Ecosystems approach as a state-wide landscape classification scheme. For the Cape York Peninsula bioregion in north-eastern Australia, Regional Ecosystems (RE) were initially recognised based on a pre-existing vegetation map and classification for the bioregion. The classification had been developed using expert-techniques based on extensive field plot data. Here, we use numerical analyses to classify the field plot data and identify savanna plant communities associated with two widespread landform groups in the bioregion (the old loamy and sandy plains (land zone 5) and the hills and lowlands on igneous rocks (land zone 12). Communities were identified at the plant association level, using species importance values calculated from foliage cover and vegetation height at each plot. We developed a descriptive-framework for each community using statistically based characterising species and biophysical attributes. We recognise 57 communities compared with 110 that had been previously identified using expert-techniques. This classification is used to recommend refined Regional Ecosystems under the government’s regulations. The descriptive-framework supported consistent descriptions of communities and assignment of new sites to the classification. We conclude that incorporating quantitative methods in classifying and describing plant communities will improve the robustness and defensibility of Regional Ecosystems and their use in landscape management across Queensland.