An indirect gradient analysis of the ecological relationships between ancient and recent reiverine woodlands to the south of Bruges (Flanders, Belgium)

Vegetatio ◽  
1981 ◽  
Vol 44 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Martin Hermy ◽  
Herman Stieperaere
Keyword(s):  
Gradient Analysis ◽  
The South ◽  
Indirect Gradient Analysis ◽  
Ecological Relationships

scholarly journals The rediscovery of the Red-tailed Newtonia Newtonia fanovanae in south-eastern Madagascar with notes on the natural history of the genus Newtonia

1991 ◽  
Vol 1 (1) ◽  
pp. 33-45 ◽  
Author(s):  
Steven M. Goodman ◽  
Thomas S. Schulenberg
Keyword(s):  
Natural History ◽  
Sympatric Species ◽  
The Other ◽  
Single Specimen ◽  
The South ◽  
Humid Forest ◽  
Ecological Relationships ◽  
South Eastern ◽  
History Of ◽  
Morphological Differences

SummaryThe Red-tailed Newtonia Newtonia fanovanae, previously known from a single specimen from the eastern rainforest of central Madagascar, was rediscovered in October 1989 in the Marosohy Forest in the south-east of the island. In the study area, N. fanovanae occurs in the middle and upper section of the canopy of humid forest between 300 and 1,300 m. Ecological relationships with the other two sympatric Newtonia, amphichroa and brunneicauda, are discussed. The main morphological differences between fanovanae and the other two sympatric species are that the former has relatively long wings and short tarsi. The song of fanovanae is described and compared to other members of the genus. Our observations on the morphology, behaviour and vocalisations of N. fanovanae confirm its validity as a species.Le Newtonie à queue rouge Newtonia fanovanae jusqu'à presént uniquement connu d'un seul spécimen provenant de la partie orientale de la forêt tropicale du Madagascar central, fût redécouvert en octobre 1989 dans la forêt de Marosohy au sud-est de l'île. N. fanovanae fût rencontré dans les parties moyennes et supérieures du feuillage de la forêt humide entre 300 et 1,300 m d'altitude. Les relations écologiques avec les deux espèces sympatriques de Newtonia, amphichroa et brunneicauda sont discutées. Les différences morphologiques principales entre fanovanae et les deux espéces sympatriques sont que celle-ci a des ailes relativement longues et des tarses courts. Le chant de fanovanae est decrit et comparé avec celui d'autres membres du genre. Nos observations sur la morphologie, le comportement et les vocalizations de N. fanovanae confirment sa validité comme bonne espéce.

Indirect gradient analysis of the Mangal formation of Gazi bay (Kenya)

1989 ◽  
Vol 54 ◽  
Author(s):  
H. Beeckman ◽  
E. Gallin ◽  
E. Coppejans
Keyword(s):  
Correspondence Analysis ◽  
Gradient Analysis ◽  
Stomatal Density ◽  
Detrended Correspondence Analysis ◽  
Zonation Pattern ◽  
Mangrove Species ◽  
Indirect Gradient Analysis ◽  
Ordination Method ◽  
Gazi Bay

(1)  Based on vegetation relevés of sample units along transects perpendicular to  the coastline, the mangal ecosystem of Gazi Bay (Kenya) has been  investigated.     (2) An indirect gradient analysis is performed by the ordination method  Detrended Correspondence Analysis.     (3) The first ordination axis can be interpreted in terms of resistance of  the different species to flooding.     (4) A similar zonation pattern is found as described by WALTER &  STEINER (1936).     (5) Zonation is closely connected with morphological and ecophysiological  features of the mangrove species. Therefore stomatal density has been  measured. Sonneratia has by  far the lowest stomatal density, Lumnitzera the highest.

scholarly journals Identification of Fine-Scale Marine Benthic Ecoclines by Multiple Parallel Ordination

2014 ◽  
Vol 2014 ◽  
pp. 1-23 ◽  
Author(s):  
Thijs Christiaan van Son ◽  
Rune Halvorsen ◽  
Karl Norling ◽  
Torgeir Bakke ◽  
Maria Kaurin ◽  
...  
Keyword(s):  
Species Composition ◽  
Environmental Variables ◽  
Gradient Analysis ◽  
Detrended Correspondence Analysis ◽  
Natural Ecosystems ◽  
Form Complex ◽  
Indirect Gradient Analysis ◽  
Physical Forcing ◽  
Periodic Hypoxia ◽  
Geomorphological Features

The species-environment relationship is a fundamental structural property of natural ecosystems. Marine sedimentary macrofauna is known to be structured by a range of environmental variables; however, the mechanisms by which environmental variables covary to form complex-gradients (i.e., groups of intercorrelated environmental variables), and how these are related to coenoclines (i.e., gradients in species composition), remain poorly understood. We classified our study area into geomorphological features that were used for stratified sampling of macrofaunal polychaetes, molluscs, and echinoderms. The resulting species-by-site matrix was subjected to indirect gradient analysis by a multiple parallel ordination strategy, using detrended correspondence analysis and nonmetric multidimensional scaling. One major and one minor coenocline were identified. Based on the correlation between complex-gradients and the main coenocline we hypothesise the existence of two ecoclines that we have termedPeriodic hypoxiaandPeriodic physical forcing. We conclude that a combination of recurrent (periodical) and extreme events is likely to determine the variation found in the species composition of marine sedimentary ecosystems. Based on the results of our study, we conclude that indirect gradient analysis is a useful tool for enhancement of our basic mechanistic understanding of the processes governing the compositional structure of marine sediment communities.

scholarly journals Classification and ordination of lime trees in the south of the Tyumen Region

2018 ◽  
Vol 7 (1) ◽  
pp. 123-129
Author(s):  
Maulikha Sabirovna Sharafutdinova
Keyword(s):  
Environmental Factors ◽  
Gradient Analysis ◽  
The South ◽  
Dry Forests ◽  
Ordinate Axis

The paper contains a classification of lime trees according to the method of Brown-Blanke and ordination based on isolated syntaxonomic units in the southern part of the Tyumen Region. The material for this study was 115 geobotanical descriptions of the lime trees in the southern part of the Tyumen Region. Syntaxonomic diversity of lime trees on the territory of three regions in the south of the Tyumen Region in the system of ecological and floral classification includes 8 associations and 6 variants belonging to 3 orders, 3 unions and 2 classes: Asaro europaei - Abietetea sibiriacae and Brachypodio pinnate - Betuletea pendulae . Forests of the selected associations and variants are distributed by various relationships to humidification conditions from the more humid to the steppe forests. To study the syntaxonomic diversity of lime trees, a multifactorial gradient analysis was used, where a combination of several environmental factors was simultaneously considered. Average values for four soil scales of D.N. Tsyganov and two scales of A.Yu. Korolyuk discovered 12 patterns of syntaxonomic units that revealed a certain pattern of distribution on the ordinate axis with concentration from dry forests to moist forests. The main gradient factor of location in the ecological area of lime trees associations is the presence of moisture in the soil.

scholarly journals Habitat structure and small mammals abundances in one semiarid landscape in the Brazilian Caatinga

2005 ◽  
Vol 22 (1) ◽  
pp. 119-129 ◽  
Author(s):  
Rodrigo R. Freitas ◽  
Pedro Luís B. da Rocha ◽  
Paulo César Simões-Lopes
Keyword(s):  
Small Mammals ◽  
Environmental Variables ◽  
Habitat Structure ◽  
Gradient Analysis ◽  
Direct Analysis ◽  
Indirect Gradient Analysis ◽  
Mammal Fauna ◽  
Highly Correlated ◽  
Academy Of Sciences ◽  
Major Project

Studies conducted under a major project sponsored by the Brazilian Academy of Sciences in the 1970's concluded that the small mammal fauna of the semiarid Caatinga region of Brazil is impoverished and highly restricted to mesic granite outcroppings due to the lack of water conserving physiological capabilities in its species. This work focuses the abundance of small mammals in five typical Caatinga habitats. Indirect gradient analysis shows that three theoretical environmental variables explain most of the variance present in the community abundance matrix. Direct analysis of gradients show that none of these variables is highly correlated to availability of granite outcroppings. Our data also suggest that the abundances in Caatinga are not particularly low when compared to neighbor biomes and that underlying factors of habitat use by Caatinga small mammals are more complex than previously supposed.

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