environmental gradient
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2022 ◽  
Author(s):  

This guide provides descriptions of when the species of bats resident in British and Ireland use natural and man-made rock habitats, how they use them, and the environment each species occupies within them. This data is part of the Bat Rock Habitat Key project. For the first time it brings together a) historic scientific investigations; b) useful photographic accounts; and c) open access biological records, in a practical narrative. The text encompasses: - Descriptions of the features that a climber, caver or professional ecologist might encounter on and in natural and man-made rock habitats, and within which bats have been recorded roosting. - Recording criteria for both the physical and environmental attributes of different features and situations. - The identification of suitability thresholds against which the recorded information can be compared to assess the likelihood that a specific feature might be exploited by a specific bat species. - Some suggestions for how to avoid mistakes and misery when performing a survey. The idea is that the use of the book will generate standardised biological records that will feed into the online database at www.batrockhabitatkey.co.uk. This data will be analysed to search for patterns that can increase the confidence in the suitability thresholds, build new roost features that deliver the environment each species really wants; their fundamental niche on each environmental gradient.


Author(s):  
Mozzamil Mohammed ◽  
Bernd Blasius ◽  
Alexey Ryabov

AbstractThe dynamics of trait-based metacommunities have attracted much attention, but not much is known about how dispersal and spatial environmental variability mutually interact with each other to drive coexistence patterns and diversity. Here, we present a spatially explicit model of competition for two essential resources in a metacommunity on a one-dimensional environmental gradient. We find that both the strength of dispersal and the range of spatial environmental variability affect coexistence patterns, spatial structure, trait distribution, and local and regional diversity. Without dispersal, species are sorted according to their optimal growth conditions on the gradient. With the onset of dispersal, source-sink effects are initiated, which increases the effects of environmental filtering and interspecific competition and generates trait lumping, so that only a few species from an environment-defined trait range can survive. Interestingly, for very large dispersal rates, species distributions become spatially homogeneous, but nevertheless two species at the extreme ends of the trade-off curve can coexist for large environmental variability. Local species richness follows a classic hump-shaped dependence on dispersal rate, while local and regional diversity exhibit a pronounced peak for intermediate values of the environmental variability. Our findings provide important insights into the factors that shape the structure of trait-based metacommunities.


2022 ◽  
Author(s):  
Mingjie Luo ◽  
Yinqiu Ji ◽  
Douglas W. Yu

The accurate extraction of species-abundance information from DNA-based data (metabarcoding, metagenomics) could contribute usefully to diet reconstruction and quantitative food webs, the inference of species interactions, the modelling of population dynamics and species distributions, the biomonitoring of environmental state and change, and the inference of false positives and negatives. However, capture bias, capture noise, species pipeline biases, and pipeline noise all combine to inject error into DNA-based datasets. We focus on methods for correcting the latter two error sources, as the first two are addressed extensively in the ecological literature. To extract abundance information, it is useful to distinguish two concepts. (1) Across-species quantification describes relative species abundances within one sample. (2) In contrast, within-species quantification describes how the abundance of each individual species varies from sample to sample, as in a time series, an environmental gradient, or different experimental treatments. Firstly, we review methods to remove species pipeline biases and pipeline noise. Secondly, we demonstrate experimentally (with a detailed protocol) how to use a 'DNA spike-in' to remove pipeline noise and recover within-species abundance information. We also introduce a statistical estimator that can partially remove pipeline noise from datasets that lack a physical DNA spike-in.


Author(s):  
Marit Reigstad ◽  
Tove Gabrielsen ◽  
Marti Amargant ◽  
Rita Amundsen ◽  
Bodil Bluhm ◽  
...  

The Nansen Legacy Q3 cruise, 5-27 August 2019, initiated the seasonal investigations of the Nansen Legacy transect. The transect represent an environmental gradient going through the northern Barents Sea, and included 7 process stations (P1-P7) lasting 6-53 hrs. CTD stations were taken to increase the hydrographic resolution on the transect. The program included measurements and sampling from the atmosphere, sea ice, ocean and sea floor. Data collected ranged from physical observations, chemical, biological and geological data collection, and the aim was to link observations and measurements to improve our understanding of the systems involving both climate, human impacts and the ecosystems. Deployment of moorings and gliders extended the observational capacity in time and space, outside the cruise period.


2021 ◽  
Vol 9 (3) ◽  
pp. 107-113
Author(s):  
Bing-Hua Liao

A key plant species (Senecio L.) not only is a vital multilevel functional medicinal material of indications of respiratory tract infections, tonsillitis, pharyngitis, pneumonia, conjunctivitis, enteritis, dysentery, but also it is a widely distributed wide plant species. This plant species is widely distributed elevation from 500m to 1500m in six landscapes in Shan County of China. However, understanding dynamics of stems moisture of the plants is difficult along elevation. Herein showed that relations between stems moisture of the species and elevation is a significant positive connection from 500m to 1000m (P<0.01) as well as relationships between stems moisture of this species to elevation is a significant negative connection from 1000m to 1500m (P<0.01). This study provides six types and eco-adaptation for finding new species. Therefore, this study has theoretical and practical significance for plants protection along elevation and environmental gradient over the spatial-temporal-environmental-disturbance scales (STEDS) in the multilevel green space diversity.


2021 ◽  
Vol 4 (1) ◽  
pp. 129-135
Author(s):  
Bing-Hua Liao

A key plant species (Senecio L.) not only is a vital multilevel functional medicinal material of indications of respiratory tract infections, tonsillitis, pharyngitis, pneumonia, conjunctivitis, enteritis, dysentery, but also it is a widely distributed wide plant species. This plant species is widely distributed elevation from 500m to 1500m in six landscapes and vegetation ecosystems in Shan County of China. However, understanding dynamics of dry biomass of this species is difficult along elevation. This research explained that the relation between fresh biomass of the species and elevation is a significant positive connection from 500m to 1000m (P<0.01) as well as the links between fresh biomass of this species and elevation is a significant negative connection from 1000m to 1500m (P<0.01). This study provides six ecosystem types and a series of areas ecological adaptation for finding new medicinal species. Therefore, this study has vital theoretical and practical significance for medicinal plant protection along different elevation and environmental gradient over the spatial-temporal-environmental-disturbance scales (STEDS) in the multilevel green space diversity.


Author(s):  
Matthieu Alfaro ◽  
Gwenaël Peltier

We consider a population structured by a space variable and a phenotypical trait, submitted to dispersion, mutations, growth and nonlocal competition. This population is facing an environmental gradient: to survive at location [Formula: see text], an individual must have a trait close to some optimal trait [Formula: see text]. Our main focus is to understand the effect of a nonlinear environmental gradient. We thus consider a nonlocal parabolic equation for the distribution of the population, with [Formula: see text], [Formula: see text]. We construct steady states solutions and, when [Formula: see text] is periodic, pulsating fronts. This requires the combination of rigorous perturbation techniques based on a careful application of the implicit function theorem in rather intricate function spaces. To deal with the phenotypic trait variable [Formula: see text] we take advantage of a Hilbert basis of [Formula: see text] made of eigenfunctions of an underlying Schrödinger operator, whereas to deal with the space variable [Formula: see text] we use the Fourier series expansions. Our mathematical analysis reveals, in particular, how both the steady states solutions and the fronts (speed and profile) are distorted by the nonlinear environmental gradient, which are important biological insights.


Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2712
Author(s):  
Ahmed M. Abbas ◽  
Fatma A. A. Ayed ◽  
Mohamed G. Sheded ◽  
Sulaiman A. Alrumman ◽  
Tarek A. A. Radwan ◽  
...  

The present study analyses plant diversity and evaluates the relationship between edaphic variables and the distribution and grouping of plant species in the Aswan Reservoir area, South Egypt. The dominant families were Fabaceae, Poaceae, and Asteraceae, forming 38.82% of the total flora recorded. The main bulk of the flora recorded (50.59%) belonged to the cosmopolitan, neotropical, pantropical, and palaeotropical chorotypes. A TWINSPAN analysis produced 10 vegetation clusters. Inundation levels showed a high correlation with species richness. The seasonally inundated area in Bute El-Hasaya and Maezana Belal (cluster V) had the highest species richness (36.50), while the lowest species richness (4.50) was in the shoreline of Philae, Awad, and Heisa islands (cluster IX). The DCA ordination depicted the environmental gradient expressed by the cluster analysis, and the resulting vegetation groups represented a distinct microhabitat. The CCA ordination indicates that the separation of vegetation group (A) along the axis was affected by the concentration of K, Mg, and CO3, and the vegetation group (B) was significantly associated with the total dissolved salts and the concentration of Cl. Moreover, the vegetation group (C) correlated significantly with pH, electrical conductivity, organic matter content, and SO3, HCO3, PO4, Na, and Ca concentrations.


2021 ◽  
Author(s):  
Thomas Cortier ◽  
Nicolas Loeuille

Global changes currently cause temporal shifts in the favourable conditions for different phases of species life cycles. Phenologies characterizing temporal presence, may adapt through heritable evolution in response to these changes. Given a community context, this evolution may cause a change in the phenology overlap and thus a change of interspecific interactions such as competition. Using a model in which phenologies compete and coevolve, we study the conditions under which diversity emerges, as well as their annual distribution. We find that the environment richness (food quantity, light, pollinators, etc) and competition constrain the diversity and spread of phenologies. A robust pattern of phenologies distribution emerges consistent with Swedish flowering observations. Once a stable community is reached, we apply a progressive change in environmental conditions. We found that adaptation eventually restored diversity, but that the simulated change often led to numerous extinctions due to increased competition. The percentage of diversity lost depends on the speed of change and on the initial diversity. Phenologies already pre-adapted to the new environmental conditions drive the restoration of diversity after the change. We finally study a spatial version of the model in which local communities are organized along an environmental gradient. Pre-change, allowing dispersal decreases the local adaptation of phenologies to their local fixed environmental conditions. Dispersal however largely enhances the maintenance of biodiversity in changing environments, though its benefits are not homogeneous in space. Evolution remains the only rescue mechanism for southern phenotypes.


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