scholarly journals Disentangling the drivers of metacommunity structure across spatial scales

2013 ◽  
Vol 40 (8) ◽  
pp. 1560-1571 ◽  
Author(s):  
Christine N. Meynard ◽  
Sébastien Lavergne ◽  
Isabelle Boulangeat ◽  
Luc Garraud ◽  
Jérémie Van Es ◽  
...  
2013 ◽  
Author(s):  
Diogo B. Provete ◽  
Thiago Gonçalves-Souza ◽  
Michel Garey ◽  
Itamar A. Martins ◽  
Denise Rossa-Feres

Spatial and environmental processes influence species composition at distinct scales. Previous studies suggested that the landscape-scale distribution of larval anurans is influenced by environmental gradients related to adult breeding site selection, such as pond canopy cover, but not water chemistry. However, the combined effects of spatial, pond morphology, and water chemistry variables on metacommunity structure of larval anurans have not been analyzed. We used a partial redundancy analysis with variation partitioning to analyze the relative influence of pond morphology (e.g., depth, area, and aquatic vegetation), water chemistry, and spatial variables on a tadpole metacommunity from southeastern Brazil. We predict that the metacommunity will be spatially structured at broad spatial scales, while environmental variables, mainly related to adult habitat selection, would play a larger role at fine spatial scales. We found that broad-scale spatial patterns of pond canopy cover and pond morphology strongly influenced metacommunity structure. Additionally, species composition was spatially autocorrelated at short distances. We suggest that the reproductive behavior of adult anurans is driving tadpole metacommunity dynamics, since pond morphology, but not water chemistry affects breeding site selection by adults. Our results contribute to the understanding of amphibian species diversity in tropical environments.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6472 ◽  
Author(s):  
Fernanda Alves-Martins ◽  
Leandro Schlemmer Brasil ◽  
Leandro Juen ◽  
Paulo De Marco Jr ◽  
Juliana Stropp ◽  
...  

BackgroundWe identified and classified damselfly (Zygoptera) and dragonfly (Anisoptera) metacommunities in Brazilian Amazonia, relating species distribution patterns to known biological gradients and biogeographical history. We expected a random distribution of both Zygoptera and Anisoptera within interfluves. At the Amazonian scale, we expected Anisoptera metacommunities to be randomly distributed due to their higher dispersal ability and large environmental tolerance. In contrast, we expected Zygoptera communities to exhibit a Clementsian pattern, limited by the large Amazonia rivers due to their low dispersal ability.MethodsWe used a dataset of 58 first-to-third order well-sampled streamlets in four Amazonian interfluves and applied an extension of the Elements of Metacommunity Structure (EMS) framework, in which we order Zygoptera and Anisoptera metacommunities by known spatial and biogeographic predictors.ResultsAt the Amazonian scale, both Zygoptera and Anisoptera presented a Clementsian pattern, driven by the same environmental and biogeographical predictors, namely biogeographic region (interfluve), annual mean temperature, habitat integrity and annual precipitation. At the interfluve scale, results were less consistent and only partially support our hypothesis. Zygoptera metacommunities at Guiana and Anisoptera metacommunities at Tapajós were classified as random, suggesting that neutral processes gain importance at smaller spatial scales.DiscussionOur findings were consistent with previous studies showing that environmental gradients and major rivers limit the distribution of Odonata communities, supporting that larger Amazonian rivers act as barriers for the dispersal of this group. In addition, the importance of habitat integrity indicates that intactness of riparian vegetation is an important filter shaping metacommunity structure of Amazonian stream Odonata.


2020 ◽  
Vol 10 (6) ◽  
pp. 2874-2884 ◽  
Author(s):  
Siwen He ◽  
Janne Soininen ◽  
Guiping Deng ◽  
Beixin Wang

2017 ◽  
Vol 7 (9) ◽  
pp. 3190-3200 ◽  
Author(s):  
Leandro Schlemmer Brasil ◽  
Thiago Bernardi Vieira ◽  
José Max Barbosa de Oliveira-Junior ◽  
Karina Dias-Silva ◽  
Leandro Juen

2019 ◽  
Vol 130 ◽  
pp. 55-62 ◽  
Author(s):  
Yuxi Guo ◽  
Meixiang Gao ◽  
Jie Liu ◽  
Andrey S. Zaitsev ◽  
Donghui Wu

Author(s):  
J. R. Michael

X-ray microanalysis in the analytical electron microscope (AEM) refers to a technique by which chemical composition can be determined on spatial scales of less than 10 nm. There are many factors that influence the quality of x-ray microanalysis. The minimum probe size with sufficient current for microanalysis that can be generated determines the ultimate spatial resolution of each individual microanalysis. However, it is also necessary to collect efficiently the x-rays generated. Modern high brightness field emission gun equipped AEMs can now generate probes that are less than 1 nm in diameter with high probe currents. Improving the x-ray collection solid angle of the solid state energy dispersive spectrometer (EDS) results in more efficient collection of x-ray generated by the interaction of the electron probe with the specimen, thus reducing the minimum detectability limit. The combination of decreased interaction volume due to smaller electron probe size and the increased collection efficiency due to larger solid angle of x-ray collection should enhance our ability to study interfacial segregation.


2014 ◽  
Vol 11 (1) ◽  
pp. 90-100
Author(s):  
Yigit Aydede

The present study intends to reveal spatial regularities between non-immigrant and immigrant numbers in two different ways. First, it questions the existence of those regularities when spatial scales get finer. Second, it uses pooled data over four population censuses covering the period from 1991 to 2006, which enabled us to apply appropriate techniques to remove those unobserved fixed effects so that the estimations would accurately identify the linkage between local immigrant and non-immigrant numbers. The results provide evidence about the existence of negative spatial regularities between non-immigrant and immigrant numbers in Canada at national scale.


2019 ◽  
Vol 612 ◽  
pp. 29-42 ◽  
Author(s):  
NR Evensen ◽  
C Doropoulos ◽  
KM Morrow ◽  
CA Motti ◽  
PJ Mumby

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Jan Piekarczyk

AbstractWith increasing intensity of agricultural crop production increases the need to obtain information about environmental conditions in which this production takes place. Remote sensing methods, including satellite images, airborne photographs and ground-based spectral measurements can greatly simplify the monitoring of crop development and decision-making to optimize inputs on agricultural production and reduce its harmful effects on the environment. One of the earliest uses of remote sensing in agriculture is crop identification and their acreage estimation. Satellite data acquired for this purpose are necessary to ensure food security and the proper functioning of agricultural markets at national and global scales. Due to strong relationship between plant bio-physical parameters and the amount of electromagnetic radiation reflected (in certain ranges of the spectrum) from plants and then registered by sensors it is possible to predict crop yields. Other applications of remote sensing are intensively developed in the framework of so-called precision agriculture, in small spatial scales including individual fields. Data from ground-based measurements as well as from airborne or satellite images are used to develop yield and soil maps which can be used to determine the doses of irrigation and fertilization and to take decisions on the use of pesticides.


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