scholarly journals Factors affecting microphytobenthic biomass, species composition and production in the Colne Estuary (UK)

2002 ◽  
Vol 27 ◽  
pp. 285-300 ◽  
Author(s):  
DCO Thornton ◽  
LF Dong ◽  
GJC Underwood ◽  
DB Nedwell
Keyword(s):  
Species Composition ◽  
Factors Affecting ◽  
Colne Estuary

Augmentative Restoration: Repairing Damaged Ecological Processes During Restoration of Heterogeneous Environments

2009 ◽  
Vol 2 (1) ◽  
pp. 10-21 ◽  
Author(s):  
Roger L. Sheley ◽  
Jeremy J. James ◽  
Erin C. Bard
Keyword(s):  
Species Composition ◽  
Native Species ◽  
Plant Performance ◽  
Meadow Vole ◽  
Heterogeneous Environments ◽  
Ecological Processes ◽  
Additional Advantage ◽  
Factors Affecting ◽  
Ephemeral Wetland ◽  
Species Performance

AbstractHeterogeneity in disturbance regimes, propagule pools, and factors affecting plant performance are a ubiquitous feature of wildlands. We tested a conceptual framework, termed augmentative restoration, aimed at identifying and selectively repairing or replacing damaged processes based on their predicted influence on the three causes of succession: site availability, species availability, and species performance. This framework was tested at three sites each with a different cause of succession naturally occurring in an ephemeral wetland dominated by invasive plants that had varying levels of disturbance (site availability), remnant native plants (species availability), and water availability (species performance). Our hypotheses were (1) seeding combined with watering would augment meadow vole disturbance to increase desired species composition, (2) shallow tilling combined with watering would augment remnant native species, and (3) shallow tilling combined with seeding would augment mesic soils to increase desired species composition. Shallow tilling, watering, and seeding were applied in a factorial arrangement at all three sites. These eight treatment combinations were applied in a split-plot design with four replications to generate 32 whole plots (2 m2). The herbicide 2,4-D was applied on half of each whole plot to influence relative species performance. In two of the three sites, using augmentative restoration to guide our management approaches improved our decision as to the treatment combinations that would maximize seedling establishment. Selectively augmenting successional processes that remain intact by repairing or replacing processes occurring at inadequate levels can improve implementation of successional management and provide a refined process-based framework for restoration across heterogeneous landscapes. Besides the clear economic advantages of lower management inputs associated with augmentative restoration, avoiding unnecessary management inputs has the additional advantage of minimizing unintended negative impacts on ecosystem processes.

Blackfly (Diptera, Simuliidae) communities and species richness estimation in Carpathian montane streams

2013 ◽  
Vol 8 (7) ◽  
pp. 681-692 ◽  
Author(s):  
Andrej Štangler ◽  
Jozef Halgoš ◽  
Pavel Beracko
Keyword(s):  
Species Richness ◽  
Environmental Factors ◽  
Species Composition ◽  
Flow Speed ◽  
Factors Affecting ◽  
Typical Species ◽  
Species Richness Estimation ◽  
West Carpathians ◽  
Montane Streams ◽  
First Time

AbstractThe present work gives the result of blackfly fauna research of the Slovenský raj (West Carpathians, Slovakia). Our aim was to describe the composition of blackfly communities, find indicator species for communities, describe environmental factors affecting communities and determine the potential changes in species richness. Research was carried out in 2007 and 2008. The presence of 22 species of blackflies was confirmed at 20 sites in the area of Slovenský raj. 12 species were recorded for the first time in this area. The potential for further increase in diversity was calculated by a nonparametric estimation of species richness. Two main groups of sites with their typical blackflies communities were indentified using a TWINSPAN analysis. The presence of Simulium ornatum, S. variegatum and S. argyreatum was typical in larger streams in broad valleys. The absence or low abundance of these species was typical for smaller streams in canyons. Based on the species composition of blackflies communities, we identified 6 groups of sites: 1. anthropogenically disturbed submountain rivers (typical species: Simulium ornatum, S. reptans, S. equinum), 2. undisturbed metarhithral (typical species: Simulium bertrandi, S. codreanui, S. costatum, S. vernum, S. argenteostriatum, S. degrangei, S. argyreatum, S. variegatum), 3. undisturbed hyporhithral (typical species: Simulium trifasciatum, S. tuberosum), 4. undisturbed epirhithral (typical species: Prosimulium hirtipes, P. rufipes), 5. hypocrenal (typical species: Simulium cryophilum, S. monticola) and 6. anthropogenically disturbed epirhithral (typical species: Simulium brevidens, S. maximum). The most important environmental factors explaining differences in species composition like altitude, flow speed, pH, conductivity, oxygen saturation, sulphates concentration and presence of riparian vegetation were identified by the CCA analysis.

scholarly journals Species composition and similarities among anuran assemblages of forest sites in southeastern Brazil

2007 ◽  
Vol 64 (4) ◽  
pp. 364-374 ◽  
Author(s):  
Jaime Bertoluci ◽  
Ricardo Augusto Brassaloti ◽  
José Wagner Ribeiro Júnior ◽  
Vívian Maria de Faria Nasser Vilela ◽  
Henrique Oliveira Sawakuchi
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Southeastern Brazil ◽  
Neotropical Forests ◽  
Breeding Sites ◽  
Factors Affecting ◽  
Anuran Species ◽  
Forest Sites ◽  
Complementary Techniques ◽  
Data Deficient

Neotropical forests show high anuran species richness, but some Brazilian forest formations, like cerradão, semideciduous forests and restingas, remain poorly known. The composition of anuran species were determined for four forest sites belonging to different biomes in southeastern Brazil, based on two complementary techniques (visual encounter survey and survey on breeding sites), both applied simultaneously. A total of 60 anuran species belonging to eight families was recorded. Species richness and levels of endemism were higher in the Atlantic rainforest site. Sites located in the Cerrado domain were more alike than those located in the Atlantic Forest Domain. Similarity in anuran species composition was negatively correlated to the geographical distance among sites, which explains part of similarities in species composition. Factors affecting these occurrence patterns are discussed. One species (if its identity is confirmed) is considered Data Deficient by IUCN (The World Conservation Union), though it is not included in the Brazilian list of threatened amphibians. The presence of certain species with special habitats and microclimate requirements (bioindicators) suggests well-preserved ecosystems.

Effects of environmental factors on weed species composition of cereal and stubble fields in western Hungary

2010 ◽  
Vol 5 (2) ◽  
pp. 283-292 ◽  
Author(s):  
Gyula Pinke ◽  
Robert Pál ◽  
Zoltán Botta-Dukát
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Soil Ph ◽  
Vegetation Period ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Weed Species ◽  
Factors Affecting ◽  
Weed Communities ◽  
Winter Annuals

AbstractMultivariate analysis of data obtained from 184 cereal and stubble fields in low-input agricultural systems located in western Hungary was undertaken in order to asses environmental factors affecting weed species composition. For each variable, the gross and net effect on weed species composition was calculated. All variables considered in this study had a significant effect on weed species composition and explained 26.99% of the total variation. Most variation in species composition was explained by the aspect (cereal vs. stubble), followed by soil pH, mean annual precipitation, soil texture, mean annual temperature, and altitude. Separating the cereals and stubbles soil pH became the most important factor. Our results suggest that during the long vegetation period, cereal weed communities dominated by winter annuals are replaced by stubble-field weed communities dominated by summer annuals. This seasonal change may also have the same important effect on weed species composition as crop types.

scholarly journals Factors Affecting Lichen Diversity in Manor Parks of Pskov Region (Northwestern Russia)

2021 ◽  
Vol 35 ◽  
pp. 19-33
Author(s):  
N. B. Istomina ◽  
◽  
O. V. Likhacheva ◽  
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Lichen Species ◽  
Species Number ◽  
Dispersion Pattern ◽  
Natural Forests ◽  
Forest Zone ◽  
Factors Affecting ◽  
Lichen Diversity ◽  
The Impact

The article describes the results of studies of the factors affecting lichen diversity in 46 manor parks of the region of Pskov. The investigated parks were founded in the end of XVIII – beginning of XX centuries. Twenty of them are fragmented and currently occupy less than 5 ha, the area of nine parks varies from 5 to 10 ha, those preserved within historical boundaries cover from 11 to 100 ha. Manor parks are situated both within the settlements’ boundaries (31 parks) and outside the settlements either bordering forest (12) or agricultural lands (3). Ten of the former border the forests. During the study 166 lichen species were identified. Statistical methods were performed to investigate the factors affecting lichen diversity in manor parks. Linear regression analysis was used to examine the dependence of the lichens species number on the park age/date of park creation (dispersion pattern), area of the parks (box plot), substrata diversity (dispersion pattern), and the dependence of the epiphytic lichens species number on tree and shrub species diversity (dispersion pattern). With the biserial correlation coefficient the impact of the settlement and the presence of the surrounding natural forests was calculated. Correlation analysis was performed to demonstrate the colligation between lichen species composition of the parks located in different subzones of forest zone in the region of Pskov. Our findings show that the number of lichen species depends on the park area (p = 0,0315), the variety of substrate types (p ˂ 0,001), and the variety of trees and bushes planted (p ˂ 0,001). The date of park creation and the presence of the surrounding natural forests do not influence the species diversity of lichens. We reveal that the location of the parks in a specific subzone of forest zone (southern taiga and mixed coniferous-broad-leaved forest) has no significant effect on the lichen species composition. The species richness of lichens tends to decrease in parks located within the settlements. The data obtained indicate not only the similarity of the species composition of lichens in the studied communities, but also the long-term development of lichen park communities in comparable climatic and landscape conditions.

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