Environmental factors responsible for shaping an open peatland – forest complex on the hypermaritime north coast of British Columbia

2003 ◽  
Vol 33 (12) ◽  
pp. 2380-2394 ◽  
Author(s):  
Taro Asada ◽  
Barry G Warner ◽  
Jim Pojar
Keyword(s):  
British Columbia ◽  
Environmental Factors ◽  
Plant Communities ◽  
Environmental Variables ◽  
Groundwater Table ◽  
North Coast ◽  
Minimum Level ◽  
Peat Accumulation ◽  
Upland Forest ◽  
Vegetation Gradient

The relationships between the distribution of plant communities and environmental factors were studied in an open peatland – forest complex of the hypermaritime north coast of British Columbia. The entire vegetation gradient, from open through forested peatlands to upland forest, was primarily explained by slope and minimum level of groundwater table. Environmental conditions in the upland Tsuga–Rhytidiadelphus forest were considerably different from those of the other communities; differences were small among the Sphagnum open peatland, the Pinus–Sphagnum woodland, the Chamaecyparis–Fauria forest, and the Thuja–Gaultheria forest. Highest level of groundwater table, conductivity minimum, pH, and dissolved oxygen merely helped distinguish the upland Tsuga–Rhytidiadelphus forest from all other communities. The wet Thuja–Gaultheria forest could be more vulnerable than the upland Tsuga–Rhytidiadelphus forest to local hydrological changes caused by harvesting. Consecutive intraannual measurements of environmental variables are important in clarifying the relationships between distribution of plant communities and environmental variables, especially for communities with peat accumulation.

scholarly journals Environmental factors that influence species diversity of floodplain plant communities in different flooding phases in the Okavango Delta, Botswana

Bothalia ◽  
2020 ◽  
Vol 50 (Volume 50 No. 1) ◽  
Author(s):  
Gaolathe Tsheboeng ◽  
Mphaphi Bonyongo ◽  
Mike Murray-Hudson
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Plant Communities ◽  
Water Depth ◽  
Environmental Variables ◽  
Okavango Delta ◽  
Before And After ◽  
Okavango River ◽  
Flooding Duration ◽  
Species Composition And Distribution

Background and objectives: Species composition and distribution in seasonal floodplain plant communities are influenced by variation in flooding. However, the influence of intra-flooding variation phases on the diversity of seasonal floodplain plant communities has not been studied in the Okavango Delta. The objective of this study was to investigate environmental factors that influence species composition and distribution of seasonal floodplain communities before and after flooding. It was hypothesised that environmental factors that influence the species composition and distribution in seasonal floodplain communities will vary with intra-flooding seasons. Methods: Flooding depth was measured in May (before flooding) and September (flood recession/after flooding) in forty 25 m2 plots. Flooding duration was recorded as the number of weeks in which the plots were inundated. The soil was sampled before and after floods and analysed for pH, extractable P, K, Mg, Ca and Na. Plant identification and estimation of percentage cover were done in the 25 m2 plots in which environmental variables were sampled. The relationship between environmental variables and seasonal floodplain plant community composition and distribution was sought using Non-metric Multi-dimensional Scaling. Paired Student’s t test was used to compare the means of environmental variables before and after flooding. Results: Factors that influenced the distribution of species before flooding were Na, K, water depth and flooding duration. After flooding, the factors that influenced species composition and distribution were K, Na, Mg, pH, water depth and flooding duration. Conclusion: These results suggest that during flooding K and Mg are deposited in the floodplains due to lateral water flow. Our results also suggest that any water abstraction from the Okavango River Basin should take into consideration the importance of flooding duration and depth in sustaining species composition and distribution of seasonal floodplain plant communities so that such developments do not disturb the ecological functioning of the Delta.

scholarly journals Distribution of saltmarsh plant communities associated with environmental factors along a latitudinal gradient on the south-west Atlantic coast

2006 ◽  
Vol 33 (5) ◽  
pp. 888-900 ◽  
Author(s):  
J. P. Isacch ◽  
C. S. B. Costa ◽  
L. Rodriguez-Gallego ◽  
D. Conde ◽  
M. Escapa ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Plant Communities ◽  
Latitudinal Gradient ◽  
Atlantic Coast ◽  
The South ◽  
South West

scholarly journals Evidence for Freshwater Residualism in Coho Salmon, Oncorhynchus kisutch, From a Watershed on the North Coast of British Columbia

2017 ◽  
Vol 130 (4) ◽  
pp. 336 ◽  
Author(s):  
Eric A Parkinson ◽  
Chris J Perrin ◽  
Daniel Ramos-Espinoza ◽  
Eric B Taylor
Keyword(s):  
British Columbia ◽  
Fresh Water ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Water Levels ◽  
North Coast ◽  
The North ◽  
Seaward Migration ◽  
Mature Fish

The Coho Salmon, Oncorhynchus kisutch, is one of seven species of Pacific salmon and trout native to northeastern Pacific Ocean watersheds. The species is typically anadromous; adults reproduce in fresh water where juveniles reside for 1–2 years before seaward migration after which the majority of growth occurs in the ocean before maturation at 2–4 years old when adults return to fresh water to spawn. Here, we report maturation of Coho Salmon in two freshwater lakes on the north coast of British Columbia apparently without their being to sea. A total of 15 mature fish (11 males and four females) were collected in two lakes across two years. The mature fish were all at least 29 cm in total length and ranged in age from three to five years old. The occurrence of Coho Salmon that have matured in fresh water without first going to sea is exceedingly rare in their natural range, especially for females. Such mature Coho Salmon may represent residual and distinct breeding populations from those in adjacent streams. Alternatively, they may result from the ephemeral restriction in the opportunity to migrate seaward owing to low water levels in the spring when Coho Salmon typically migrate to sea after 1–2 years in fresh water. Regardless of their origin, the ability to mature in fresh water without seaward migration may represent important adaptive life history plasticity in response to variable environments.

scholarly journals Distribution Patterns of Odonate Assemblages in Relation to Environmental Variables in Streams of South Korea

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 152 ◽  
Author(s):  
Da-Yeong Lee ◽  
Dae-Seong Lee ◽  
Mi-Jung Bae ◽  
Soon-Jin Hwang ◽  
Seong-Yu Noh ◽  
...  
Keyword(s):  
Land Use ◽  
Ecosystem Services ◽  
Environmental Factors ◽  
South Korea ◽  
Habitat Heterogeneity ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Distribution Patterns ◽  
Self Organizing Map ◽  
Factors Affecting

Odonata species are sensitive to environmental changes, particularly those caused by humans, and provide valuable ecosystem services as intermediate predators in food webs. We aimed: (i) to investigate the distribution patterns of Odonata in streams on a nationwide scale across South Korea; (ii) to evaluate the relationships between the distribution patterns of odonates and their environmental conditions; and (iii) to identify indicator species and the most significant environmental factors affecting their distributions. Samples were collected from 965 sampling sites in streams across South Korea. We also measured 34 environmental variables grouped into six categories: geography, meteorology, land use, substrate composition, hydrology, and physicochemistry. A total of 83 taxa belonging to 10 families of Odonata were recorded in the dataset. Among them, eight species displayed high abundances and incidences. Self-organizing map (SOM) classified sampling sites into seven clusters (A–G) which could be divided into two distinct groups (A–C and D–G) according to the similarities of their odonate assemblages. Clusters A–C were characterized by members of the suborder Anisoptera, whereas clusters D–G were characterized by the suborder Zygoptera. Non-metric multidimensional scaling (NMDS) identified forest (%), altitude, and cobble (%) in substrata as the most influential environmental factors determining odonate assemblage compositions. Our results emphasize the importance of habitat heterogeneity by demonstrating its effect on odonate assemblages.

scholarly journals Variations on the larval incubation of Anodontites trapesialis (Unionoida, Mycetopodidae): Synergetic effect of the environmental factors and host availability

2012 ◽  
Vol 72 (3) ◽  
pp. 545-552 ◽  
Author(s):  
CT. Callil ◽  
D. Krinski ◽  
FA. Silva
Keyword(s):  
Environmental Factors ◽  
Temporal Variation ◽  
Environmental Variables ◽  
Freshwater Mussels ◽  
Synergetic Effect ◽  
Flood Pulse ◽  
Host Availability

The unionid Anodontites trapesilais (Lamarck, 1819) like most freshwater mussels is a parasite of fish. So it is trivial to assume that the availability of hosts is an important factor for the maintenance of unionoid populations. What seems obvious is not always so easy to demonstrate. This study proposes to investigate the effects of abiotic and biotic variables related to the incubation of larvae in A. trapesialis. For this, we estimate different biological indexes and try to capture the dimensionality of the fish, along with the temporal variation of environmental variables. From the application of a CCA, it was demonstrated that there was a synchronicity among the factors and variables proposed here, and we infer that the flood pulse acts as a synergistic factor in this process.

scholarly journals Geographically weighted regression modelling of the spatial association between malaria cases and environmental factors in Cameroon.

2020 ◽  
Author(s):  
Marlvin Anemey Tewara ◽  
Liu Yunxia ◽  
Weiqiang Ling ◽  
Binang Helen Barong ◽  
Prisca Ngetemalah Mbah-Fongkimeh ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Spatial Variability ◽  
Geographically Weighted Regression ◽  
Environmental Variables ◽  
Vegetation Index ◽  
Spatial Association ◽  
Ordinary Least Squares ◽  
Variable Coefficients ◽  
Weighted Regression ◽  
Gwr Model

Abstract Background: Studies have illustrated the association of malaria cases with environmental factors in Cameroon but limited in addressing how these factors vary in space for timely public health interventions. Thus, we want to find the spatial variability between malaria hotspot cases and environmental predictors using Geographically weighted regression (GWR) spatial modelling technique.Methods: The global Ordinary least squares (OLS) in the modelling spatial relationships tool in ArcGIS 10.3. was used to select candidate explanatory environmental variables for a properly specified GWR model. The local GWR model used the global OLS candidate variables to examine, predict and explore the spatial variability between environmental factors and malaria hotspot cases generated from Getis-Ord Gi* statistical analysis. Results: The OLS candidate environmental variable coefficients were statistically significant (adjusted R2 = 22.3% and p < 0.01) for a properly specified GWR model. The GWR model identified a strong spatial association between malaria cases and rainfall, vegetation index, population density, and drought episodes in most hotspot areas and a weak correlation with aridity and proximity to water with an overall model performance of 0.243 (adjusted R2= 24.3%).Conclusion: The generated GWR maps suggest that for policymakers to eliminate malaria in Cameroon, there should be the creation of malaria outreach programs and further investigations in areas where the environmental variables showed strong spatial associations with malaria hotspot cases.

scholarly journals Longitudinal and seasonal succession of algal periphyton colonization in lowland river (Tundzha River Part of Turkey)

2016 ◽  
Author(s):  
Burak Öterler
Keyword(s):  
Environmental Factors ◽  
Dissolved Oxygen ◽  
Green Algae ◽  
Environmental Variables ◽  
Diversity Index ◽  
Seasonal Succession ◽  
Lowland River ◽  
Blue Green Algae ◽  
Periphytic Algae ◽  
Wiener Diversity Index

The aim of this paper is to determine and compare the environmental factors controlling longitudinal colonisation of periphytic algae in agricultural and urbanization effects of a lowland river, the Tundzha River, located in Turkish Tunca. To investigate the effect of the environmental factors on periphyton colonization at the river, 6 stations were selected and samples were collected between April 2012 and March 2013. Canonical correspondence analyses have been applied to clarify relationships between environmental variables and periphytic algae. During the study, the Shannon-Wiener diversity index (H′) varied from 1.62 to 3.91. The phytoplankton biovolume was positively related to pH, temperature, salinity, chlorophyll- a and nutrients, and was negatively correlated with dissolved oxygen, turbidity, and silicate. Out of the 5 divisions and of 73 identified species of phytoplankton, the diatoms, namely Fragilaria ulna, Cymbella tumida, Cocconeis placentula, Gomphonema acuminatum and Cymbella cystula were found to be dominant. In addition to these species, the biovolumes of filamentous diatom Melosira varians, filamentous blue-green algae Oscillatoria limosa, and placcoderm desmids Cosmarium botrytis were determined to be at high levels during the year. The euglenoid blooms in St.5 showed many times during the study period.

scholarly journals Longitudinal and seasonal succession of algal periphyton colonization in lowland river (Tundzha River Part of Turkey)

2016 ◽  
Author(s):  
Burak Öterler
Keyword(s):  
Environmental Factors ◽  
Dissolved Oxygen ◽  
Green Algae ◽  
Environmental Variables ◽  
Diversity Index ◽  
Seasonal Succession ◽  
Lowland River ◽  
Blue Green Algae ◽  
Periphytic Algae ◽  
Wiener Diversity Index

The aim of this paper is to determine and compare the environmental factors controlling longitudinal colonisation of periphytic algae in agricultural and urbanization effects of a lowland river, the Tundzha River, located in Turkish Tunca. To investigate the effect of the environmental factors on periphyton colonization at the river, 6 stations were selected and samples were collected between April 2012 and March 2013. Canonical correspondence analyses have been applied to clarify relationships between environmental variables and periphytic algae. During the study, the Shannon-Wiener diversity index (H′) varied from 1.62 to 3.91. The phytoplankton biovolume was positively related to pH, temperature, salinity, chlorophyll- a and nutrients, and was negatively correlated with dissolved oxygen, turbidity, and silicate. Out of the 5 divisions and of 73 identified species of phytoplankton, the diatoms, namely Fragilaria ulna, Cymbella tumida, Cocconeis placentula, Gomphonema acuminatum and Cymbella cystula were found to be dominant. In addition to these species, the biovolumes of filamentous diatom Melosira varians, filamentous blue-green algae Oscillatoria limosa, and placcoderm desmids Cosmarium botrytis were determined to be at high levels during the year. The euglenoid blooms in St.5 showed many times during the study period.

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