1,721,096 research outputs found
Survival of small isolated plant populations: an integrated approach to evaluate population viability for future conservation actions. PhD Thesis extended abstract
No full text
Ex situ seed banks and the IUCN Red List.
Full text linkExtinct, or just extinct in the wild? Plants lost from in situ habitat, but represented in seed banks, are labelled extinct despite the potential for restoration. A change in the International Union for Conservation of Nature Red List definition of extinct in the wild is needed to improve the status and prospects of threatened plant species
Biological flora of Central Europe: Marsilea quadrifolia L
No full textMarsilea quadrifolia L. is a leptosporangiate aquatic fern which has a played key role in the evolutionary history
of plants. It is characterized by heterospory, the ancestral progressive trait that led to the evolution of seeds. The
species has creeping, fleshy, adventitious roots containing multiple rhizomes. From the rhizomes a four-leaf
clover grows above the water level with a long petiole, at the base of which the sporocarps containing spores
are located. Its life cycle is characterized by alternation of generations; reproduction occurs either sexually or by
vegetative propagation. The species grows in wet habitats containing shallow water. In the natural environment
this includes lakes and small rivers; in agricultural areas it can be found in ditches and rice fields. The species can
tolerate nutrient rich waters and because of its phytoremediation properties is capable of partially counteracting
the negative effects induced by a moderate organic enrichment of sediments. It has been harvested for centuries
in Asian countries as both a food source and for ethnobotanical use in Ayurvedic medicine. Supposed medicinal
properties include antibacterial, diuretic, depurative, cytotoxic and antioxidant effects, but these require further
investigation and testing.
M. quadrifolia has a widespread distribution, occurring throughout central-southern Europe and extending
from Eurasia to tropical and temperate areas of eastern Asia and North America, where it is considered a nonnative
species. Despite its wide distribution, in its home range the species is threatened with extinction and
has already been locally extirpated in several European countries. As a result, it is listed as “Vulnerable” in the
European Union Red List due to its scattered distribution and declining population. Habitat loss and degradation,
excessive water eutrophication, and agricultural practices such as the use of herbicides, mechanization and
simplified rotation are the main threats to the species.
As it is listed in Appendix I of the Bern Convention and in Annexes II and IV of Directive 92/43/EEC as a
strictly protected species, in situ and ex situ conservation activities have been conducted in most European
countries. Reintroduction, cultivation in botanical gardens and in vitro propagation are the most commonly
applied conservation methods
Some like it hot and some like it cold, but not too much: Plant responses to climate extremes
No full textCurrent climatic models predict increasing frequency and magnitude of extreme climatic events (ECEs). Ecological studies recognize the importance of these extremes as drivers of plant growth and mortality, as well as drivers of ecological and evolutionary processes. Here we review observational and experimental studies on ECEs on herbaceous plants and shrubs. Extreme events considered were heat waves, drought, advanced or delayed snowmelt, heavy rainfalls, frosts, pulsed watering and flooding. We analysed 39 studies dealing with direct response of plant to ECEs in different ecosystems, with a particular focus on cold ecosystems (alpine and arctic). Although the number of studies increases every year, the understanding of ecological consequences of ECEs is fragmentary. In general, ECEs affected negatively on physiological processes (efficiency of photosystem II, stomatal conductance and leaf water potential), productivity and reproduction, and had consequences on population demography and recruitment several years after ECE. Indeed, the plant responses to ECEs were species specific and depended on the plant life stage and the timing of ECE. In fact, the magnitude of the effect of ECEs decreased over the growing season. Drought had the most severe effect on plants, while heat waves had minor effect if water was available. The overlap of different ECEs had an additive effect (e.g. drought associated to heat-waves). In general, both neutral or positive plant responses were found and acclimation is possible. In some cases, ECEs exert a strong selective pressure on plant species. © 2014 Springer Science+Business Media Dordrecht
- …
