Search results for "EVENNESS"
showing 9 items of 19 documents
Inferring the Relative Resilience of Alternative States
2013
Ecological systems may occur in alternative states that differ in ecological structures, functions and processes. Resilience is the measure of disturbance an ecological system can absorb before changing states. However, how the intrinsic structures and processes of systems that characterize their states affects their resilience remains unclear. We analyzed time series of phytoplankton communities at three sites in a floodplain in central Spain to assess the dominant frequencies or "temporal scales" in community dynamics and compared the patterns between a wet and a dry alternative state. The identified frequencies and cross-scale structures are expected to arise from positive feedbacks that…
Biodiversidad en el Siglo XXI: más allá del conteo de especies
2018
In modern ecology, the traditional diversity indexes (usually of richness, abundance, and species evenness) have been highly revealing and useful for monitoring community and ecosystem processes. However, around two decades ago, a pioneering research team noticed that these indexes did not completely resolve their open questions. Thus, they suggested changing the way biodiversity was measured. At its base, this new methodology considers the distance between species (in phylogenetic or functional terms) before subsequently applying the appropriate biodiversity indexes. Including phylogenetic and functional elements in the evaluation of diversity allows us to approach the concept of biodivers…
Progressive Recovery of a Marine Gastropod Community Following Atmospheric Nuclear Tests in French- Polynesia: A Socio-ecological Interpretation
2021
Aims: The way species-richness is accommodated and how species-abundance distribution is organized in a hierarchic pattern is central to community ecology. Yet, the process by which species-richness and species-abundances are progressively accommodated can hardly be monitored, in practice, at a sufficiently large spatial scale. Fortunately, the progressive recovery of marine communities, after their complete destruction by atmospheric nuclear tests, yet offered unique opportunity to monitor the full process of accommodation of increasing species-richness and the associated, transient development of strong interspecific competition, all along the process of recovery.
 Methods: Taking fu…
Evenness, biodiversity, and ecosystem function of intertidal communities along the Italian coasts: Experimental short-term response to ambient and ex…
2023
Biodiversity can promote ecosystem functioning in both terrestrial and marine environments, emphasizing the neces- sity ofbiodiversity conservation in order to preserve critical ecosystem functions and associated services. However, the role of biodiversity in buffering ecosystem functioning under extreme events caused by climate change remains a major scientific issue, especially for intertidal systems experiencing stressors from both terrestrial and marine drivers. We performed a regional-scale field experiment along the Italian coast to investigate the response of unmanipulated intertidal communities (by using a natural biodiversity gradient) to low tide aerial exposure to both ambient an…
Varied response of underground and aboveground plant matter: functional diversity of three different vegetational types after translocation to reclai…
2019
The indicators of functional diversity are increasingly used to assess the conservation effectiveness of the most valuable habitats. However, little is known about the response of functional traits, their diversity, and divergence in plant communities after translocation. To assess how functional diversity changes on dry heath, meadow, and fen after translocation of entire turfs of vegetation from an airport area to the Botanical Garden in Radzionkow, we used leaf–height–seed (LHS) traits (specific leaf area, height, and seed mass) and vegetative traits (bud bank size, bud bank depth, and lateral spread). We also measured community weighted means and multifunctional diversity metrics (funct…
Effects of ecological flooding on the temporal and spatial dynamics of carabid beetles (Coleoptera, Carabidae) and springtails (Collembola) in a pold…
2011
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 str…
Inferring True Species Richness and Complete Abundance Distribution in Six Reef-fish Communities from Red-sea, Using the Numerical Extrapolation of I…
2019
Even when ecological communities are incompletely sampled (which is most frequent in practice, at least for species-rich assemblages including many rare species), it remains possible to retrieve much more information than could be expected first, by applying numerical extrapolation to incomplete field data. Indeed, recently developed procedures of numerical extrapolation of partial samplings now allow to estimate, with fair accuracy, not only the number of the still unrecorded species but, moreover, the distribution of abundances of each of these unrecorded species, thereby making available the full range of the Species Abundance Distribution, despite dealing with incomplete data only. In t…
Interspecific-Competition Strongly Constrains Species-Richness and Species-Abundance Evenness in a Tropical Marine Molluscan Community Inhabiting Cau…
2021
Increasing species-richness at the local scale (within species communities) is accommodated, first, by the diversification of the niches respectively associated to species. Yet, in case of excessive supply in colonizing species issued from the regional pool, the corresponding increase in the number of solicited niches may lead to some “niche-overcrowding” resulting in significant niche-overlaps. Then, second, strong interspecific competition for shared resource can arise, triggered by the density in individuals among those species co-occurring at niche-overlaps. Accordingly, the accommodation of species-richness within a local community involves a balance between (i) the positive contributi…
Beware of contagion!
2003
Landscape ecology starts from the assumption that diversity and spatial arrangement of ecosystem mosaics has ecological implications and tries to understand the interactions between diversity and structure of large spatially heterogeneous areas and its ecological functions. This approach implies effective use of earth observation techniques and geographic information systems, enabling a global view of the landscape mosaics. Consequently, a large number of indices has been used to quantify the structure of categorical maps as a surrogate of actual landscapes and correlate them to ecological processes. In particular, the entropy-based contagion index has been extensively used to summarize the…