scholarly journals A unified framework for species spatial patterns: Linking the occupancy area curve, Taylor's Law, the neighborhood density function and two‐plot species turnover

2021 ◽  
Author(s):  
Justin Kitzes ◽  
Micah Brush ◽  
Kyle Walters
Keyword(s):  
Density Function ◽  
Spatial Patterns ◽  
Species Turnover ◽  
Neighborhood Density ◽  
Unified Framework ◽  
Taylor’S Law

scholarly journals The many forms of beta diversity: a comment on McGill et al. and some notational suggestions

2017 ◽  
Author(s):  
Tobias Jeppsson
Keyword(s):  
Spatial Patterns ◽  
Beta Diversity ◽  
Temporal Trend ◽  
Species Turnover ◽  
Temporal Trends ◽  
Β Diversity ◽  
Different Types ◽  
Biodiversity Change ◽  
The Many

Fundamentally, beta diversity is a measure of species turnover across time or space. In practice, it is sometimes unclear exactly what aspect of beta diversity that is implied in studies. For instance, a trend in ’spatial beta diversity’ can be used to refer to both differences in spatial beta diversity between sites, as well as a temporal trend in spatial beta diversity (at the same site). In a recent review, McGill et al. [1] provide a useful and much needed overview of different aspects of biodiversity change, and show areas where we lack knowledge. Even so, McGill et al. ignore some aspects of beta diversity and sometimes pool different types of beta diversity under the same heading. However, their review mainly focused on temporal trends in diversity, while I here want to highlight spatial patterns in temporal β -diversity (species turnover) as an important but somewhat overlooked component of biodiversity change. Furthermore, I propose a slightly modified classification and nomenclature of metrics of biodiversity change, with the aim of complementing their review. The notation used here can hopefully be useful to other authors as well.

scholarly journals Geographical patterns and partition of turnover and richness components of beta-diversity in faunas from Tocantins river valley

2012 ◽  
Vol 72 (3) ◽  
pp. 497-504 ◽  
Author(s):  
MLS. Tonial ◽  
HLR. Silva ◽  
IJ. Tonial ◽  
MC. Costa ◽  
NJ. Silva Júnior ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Species Turnover ◽  
Regional Scale ◽  
Northeastern Brazil ◽  
Amphibian Species ◽  
Geographical Patterns ◽  
Β Diversity ◽  
Mantel Tests ◽  
Dispersal Abilities ◽  
Broad Scale

There has been a resurging interest in patterns of β-diversity, especially by the mechanisms driving broad-scale, continental and global patterns, and how partitioning β-diversity into richness (or nestedness) and turnover components can be linked with such mechanisms. Here we compared two recent methodologies to find richness and turnover components of β-diversity, using a large regional scale dataset of mammal, bird, reptiles and amphibian species found in seven regions of Central, North and Northeastern Brazil. As well as a simple comparison of the metrics available, we analyzed spatial patterns (i.e., distance-decay similarity) and the effects of biome type in these components using raw and partial Mantel tests. Our analyses revealed that turnover estimated using Baselga's (2010) approach is slightly higher than the estimate using Carvalho's et al. (2012) approach, but all analyses show consistent spatial patterns in species turnover using both methods. Spatial patterns in β-diversity revealed by Mantel tests are also consistent with expectations based on differential dispersal abilities. Our results also reinforce that spatial patterns in β-diversity, mainly in the turnover components expressing faunal differentiation, are determined by a mix or broad scale environmental effects and short distance spatially-structured dispersal.

Biogeographical regionalisation of Colombia: a revised area taxonomy

Phytotaxa ◽  
2021 ◽  
Vol 484 (3) ◽  
pp. 247-260
Author(s):  
CARLOS E. GONZÁLEZ-OROZCO
Keyword(s):  
Cluster Analysis ◽  
Species Richness ◽  
Plant Species ◽  
Spatial Patterns ◽  
Species Turnover ◽  
Land Plants ◽  
Geospatial Analyses ◽  
Areas Of Endemism ◽  
Biogeographic Regions ◽  
Definition Of

This study proposes a biogeographical regionalisation of Colombia based on geospatial analyses of plant species turnover and a revised area taxonomy. The spatial patterns of species turnover are calculated for 20,342 plant species in continental Colombia with distributions estimated from 271,568 georeferenced records aggregated to 414 (~50 km) grid cells across Colombia. The proposed biogeographic regions are defined by applying an agglomerative cluster analysis using a matrix of pairwise Simpson’s beta (bsim) dissimilarity values. Three main centres of species richness and 25 areas of endemism were identified across Colombia, complementing the definition of regionalisation. Biogeographical regionalisation comprises two dominions (Pacific and Boreal Brazilian), six provinces (Chocó-Darién, Guajira, Magdalena, Paramo, Sabana and Imerí) and thirty-five districts. The revised area taxonomy provides an updated and objective biogeographical classification for Colombia and is the first biogeographic regionalisation exclusively based on the taxic distributional overlap of Colombia´s land plants.

Economic Geography and the Effect of Environmental Pollution on Agglomeration

2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Andreas Lange ◽  
Martin F Quaas
Keyword(s):  
Environmental Pollution ◽  
Spatial Patterns ◽  
Economic Geography ◽  
New Economic Geography ◽  
Stability Conditions ◽  
Economic Activities ◽  
Unified Framework ◽  
Local Pollution ◽  
Different Types ◽  
The Stability

Abstract We study how local environmental pollution affects spatial patterns of economic activities when workers can migrate. Based on a New Economic Geography model, we analytically characterize the stability conditions for three different types of equilibria: symmetric spreading, partial and full agglomeration. We show that the extent of agglomeration crucially depends on the damages caused by local pollution. We thereby provide a unified framework for discussing different relationships between the extent of agglomeration and trade freeness that have been found in the literature.

scholarly journals Spatial patterns of species richness and nestedness in ant assemblages along an elevational gradient in a Mediterranean mountain range

2018 ◽  
Author(s):  
O. Flores ◽  
J. Seoane ◽  
V. Hevia ◽  
F.M. Azcárate
Keyword(s):  
Species Richness ◽  
Global Change ◽  
Spatial Patterns ◽  
Species Turnover ◽  
Elevational Gradient ◽  
Elevational Gradients ◽  
Cold Temperatures ◽  
Assemblage Composition ◽  
Ant Assemblages ◽  
High Elevations

AbstractThe study of biodiversity spatial patterns along ecological gradients can serve to elucidate factors shaping biological community structure and predict ecosystem responses to global change. Ant assemblages are particularly interesting as study cases, because ant species play a key role in many ecosystem processes and have frequently been identified as useful bioindicators. Here we analyzed the response of ant species richness and assemblage composition to elevational gradients in Mediterranean grasslands and subsequently tested whether these responses were stable spatially and temporally. We sampled ant assemblages in two years (2014, 2015) in two mountain ranges (Guadarrama, Serrota) in Central Spain, along an elevational gradient ranging from 685 to 2390 m a.s.l.Jackknife estimates of ant species richness ranged from three to 18.5 species and exhibited a hump-shaped relationship with elevation that peaked at mid range values (1100 - 1400 m). This pattern was transferable temporally and spatially. Elevation was significantly related to ant assemblage composition and facilitated separation of higher elevation assemblages (> 1700 m) from the remaining lower elevation species groups. Ant assemblages were nested; therefore species assemblages with a decreased number of species were a subset of the richer assemblages, although species turnover was more important than pure nestedness in all surveys. The degree of nestedness changed non-linearly as a cubic polynomial with elevation. These assembly patterns were observed over time but not between the two study regions.We concluded double environmental stressors typical of Mediterranean mountains explained species richness patterns: drought at low elevations and cold temperatures at high elevations likely constrained richness at both extremes of elevational gradients. The fact that species turnover showed a dominant role over pure nestedness suggested current ant assemblages were context-dependent (spatio-temporal factors) and highly vulnerable to global change, which threatens the conservation of present day native ant communities, particularly at high elevations.

scholarly journals The many forms of beta diversity: a comment on McGill et al. and some notational suggestions

2017 ◽  
Author(s):  
Tobias Jeppsson
Keyword(s):  
Spatial Patterns ◽  
Beta Diversity ◽  
Temporal Trend ◽  
Species Turnover ◽  
Temporal Trends ◽  
Β Diversity ◽  
Different Types ◽  
Biodiversity Change ◽  
The Many

Fundamentally, beta diversity is a measure of species turnover across time or space. In practice, it is sometimes unclear exactly what aspect of beta diversity that is implied in studies. For instance, a trend in ’spatial beta diversity’ can be used to refer to both differences in spatial beta diversity between sites, as well as a temporal trend in spatial beta diversity (at the same site). In a recent review, McGill et al. [1] provide a useful and much needed overview of different aspects of biodiversity change, and show areas where we lack knowledge. Even so, McGill et al. ignore some aspects of beta diversity and sometimes pool different types of beta diversity under the same heading. However, their review mainly focused on temporal trends in diversity, while I here want to highlight spatial patterns in temporal β -diversity (species turnover) as an important but somewhat overlooked component of biodiversity change. Furthermore, I propose a slightly modified classification and nomenclature of metrics of biodiversity change, with the aim of complementing their review. The notation used here can hopefully be useful to other authors as well.

The structure of amorphous and polycrystalline materials using energy-filtered RDF analysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1190-1191
Author(s):  
David Cockayne ◽  
David McKenzie
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Density Function ◽  
Electron Diffraction Pattern ◽  
Polycrystalline Materials ◽  
Nearest Neighbour ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Reduced Density ◽  
System F

The technique of Electron Reduced Density Function (RDF) analysis has ben developed into a rapid analytical tool for the analysis of small volumes of amorphous or polycrystalline materials. The energy filtered electron diffraction pattern is collected to high scattering angles (currendy to s = 2 sinθ/λ = 6.5 Å-1) by scanning the selected area electron diffraction pattern across the entrance aperture to a GATAN parallel energy loss spectrometer. The diffraction pattern is then converted to a reduced density function, G(r), using mathematical procedures equivalent to those used in X-ray and neutron diffraction studies.Nearest neighbour distances accurate to 0.01 Å are obtained routinely, and bond distortions of molecules can be determined from the ratio of first to second nearest neighbour distances. The accuracy of coordination number determinations from polycrystalline monatomic materials (eg Pt) is high (5%). In amorphous systems (eg carbon, silicon) it is reasonable (10%), but in multi-element systems there are a number of problems to be overcome; to reduce the diffraction pattern to G(r), the approximation must be made that for all elements i,j in the system, fj(s) = Kji fi,(s) where Kji is independent of s.

Successful Implicit Vocabulary Intervention for Three Cantonese-Speaking Toddlers: A Replicated Single-Case Design

2020 ◽  
Vol 63 (12) ◽  
pp. 4148-4161
Author(s):  
Christine S.-Y. Ng ◽  
Stephanie F. Stokes ◽  
Mary Alt
Keyword(s):  
Single Case ◽  
Cross Cultural ◽  
Neighborhood Density ◽  
Expressive Vocabulary ◽  
Single Case Design ◽  
Vocabulary Intervention ◽  
Phonological Neighborhood Density ◽  
Phonological Neighborhood ◽  
And Control ◽  
Case Design

Purpose We report on a replicated single-case design study that measured the feasibility of an expressive vocabulary intervention for three Cantonese-speaking toddlers with small expressive lexicons relative to their age. The aim was to assess the cross-cultural and cross-linguistic feasibility of an intervention method developed for English-speaking children. Method A nonconcurrent multiple-baseline design was used with four baseline data points and 16 intervention sessions per participant. The intervention design incorporated implicit learning principles, high treatment dosage, and control of the phonological neighborhood density of the stimuli. The children (24–39 months) attended 7–9 weeks of twice weekly input-based treatment in which no explicit verbal production was required from the child. Each target word was provided as input a minimum of 64 times in at least two intervention sessions. Treatment feasibility was measured by comparison of how many of the target and control words the child produced across the intervention period, and parent-reported expressive vocabulary checklists were completed for comparison of pre- and postintervention child spoken vocabulary size. An omnibus effect size for the treatment effect of the number of target and control words produced across time was calculated using Kendall's Tau. Results There was a significant treatment effect for target words learned in intervention relative to baselines, and all children produced significantly more target than control words across the intervention period. The effect of phonological neighborhood density on expressive word production could not be evaluated because two of the three children learned all target words. Conclusion The results provide cross-cultural evidence of the feasibility of a model of intervention that incorporated a high-dosage, cross-situational statistical learning paradigm to teach spoken word production to children with small expressive lexicons.

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