Fire and canopy species composition in the Great Lakes-St. Lawrence forest of Témiscamingue, Québec

2006 ◽  
Vol 231 (1-3) ◽  
pp. 27-37 ◽  
Author(s):  
C. Ronnie Drever ◽  
Christian Messier ◽  
Yves Bergeron ◽  
Frédérik Doyon
Keyword(s):  
Species Composition ◽  
Great Lakes ◽  
Canopy Species

Zooplankton of the St. Lawrence Great Lakes — Species Composition, Distribution, and Abundance

1974 ◽  
Vol 31 (5) ◽  
pp. 783-794 ◽  
Author(s):  
N. H. F. Watson
Keyword(s):  
Species Composition ◽  
Great Lakes ◽  
Lake Erie ◽  
Dry Weight ◽  
Individual Species ◽  
Composition Distribution ◽  
Free Weight ◽  
Sampling Intervals ◽  
Peak Abundance

Recent studies of zooplankton of the St. Lawrence Great Lakes have concentrated on a broad synoptic coverage of sampling stations and repeated cruises throughout a growing season. This has resulted in a considerable amount of detail about seasonal changes in species composition, total numbers, and vertical and horizontal distributions. Investigators have treated the data to show differences in distribution over the lakes on a cruise and cruise mean averages for each lake, often weighted by area to provide relative abundance figures over the season and between lakes.Maximum numbers were observed in Lake Erie (225,000/m3). Considerably fewer organisms were found in periods of peak abundance in Lake Ontario (55,000/m3) and Lake Huron (22,000/m3). No firm estimates are available for Lake Superior but numbers from one cruise (8000/m3) indicate still lower values there. Biomass estimates (either as ash-free weight of material from planktonnet hauls or from conversions of numbers to biomass from dry weight factors for individual species) are highest for Lake Erie, but reflect the larger size of organisms in the other lakes, especially Huron and Superior.Species distributions are now reasonably well known for crustaceans, except in one or two taxa of the cladocerans Daphnia and Bosmina whose variability should be investigated more fully. Recent studies have been made on the rotifers, but their numbers, distribution, and ecological role is not fully defined. Similarly, the distribution and role of protozoan groups have been largely ignored.Several computer techniques are suggested for the handling and analysis of the large quantities of data generated on lakewide surveys including community coefficients and cluster analyses. More attention should be given to determining sampling intervals to obtain information which can precisely detect changes in abundance from year to year, and better population dynamics and production data are needed to relate zooplankton stocks to eutrophication.

A Comparative Review of Phytoplankton and Primary Production in the Laurentian Great Lakes

1974 ◽  
Vol 31 (5) ◽  
pp. 739-762 ◽  
Author(s):  
R. A. Vollenweider ◽  
M. Munawar ◽  
P. Stadelmann
Keyword(s):  
Species Composition ◽  
Primary Production ◽  
Great Lakes ◽  
Physiological Activity ◽  
Biomass Concentration ◽  
Laurentian Great Lakes ◽  
Comparative Review

Species composition of phytoplankton in the Laurentian Great Lakes, its biomass concentration, and its physiological activity measured as photosynthesis related to eutrophication, are reviewed and discussed.

Potential impacts of fire and grazing in an endangered ecological community: plant composition and shrub and eucalypt regeneration in Cumberland Plain Woodland

2004 ◽  
Vol 52 (1) ◽  
pp. 23 ◽  
Author(s):  
Sarah J. Hill ◽  
Kristine French
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Species Interactions ◽  
Ecological Community ◽  
Plant Composition ◽  
Shrub Species ◽  
Pre Treatment ◽  
Species Richness And Abundance ◽  
The Impact ◽  
Canopy Species

Exclosure plots were used to determine the effect of fire and grazing on the structure of a grassy-woodland community. Eighteen months after fire and fence treatments were applied, the species richness, cover and composition of shrubs, trees, herbs and grasses were assessed and compared to pre-treatment censuses. Unburned plots had fewer shrub species and a lower abundance of shrubs, indicating the importance of fire in promoting regeneration of shrub species. Eucalypt species were more abundant and richer following the wildfire burn in summer, suggesting timing of fires is an important aspect in the establishment of the canopy species. Interactions between fire and grazing were found for the abundance of eucalypts (although weak) and resprouting eucalypts, suggesting a subtle interaction between fire and grazing shortly after fire. There was no effect of grazing and no interaction effect between fire and grazing on shrub species richness and abundance or tree species richness and seedling abundance.All plots showed a change in species composition despite treatment, and 46 species (32% of total richness) were recorded only in the final survey. The high rainfall during the 18-month study is likely to be an important factor in facilitating the establishment of species following all disturbances. This may have ameliorated the impact of grazing as abundant food was available throughout the woodland. The interaction between fire and grazing may be more important in structuring these grassy communities during periods of lower rainfall.

Phycological studies in lakes Ontario, Erie, Huron, and Superior

1982 ◽  
Vol 60 (9) ◽  
pp. 1837-1858 ◽  
Author(s):  
M. Munawar ◽  
I. F. Munawar
Keyword(s):  
Species Composition ◽  
Great Lakes ◽  
Primary Concern ◽  
Carbon 14 ◽  
The Past ◽  
The Subject ◽  
Processing Techniques ◽  
Canadian Research

An indepth phycological comparison is presented for lakes Ontario, Erie, Huron, and Superior, based on extensive lake-wide surveys carried out during the past 12 years. This comparison was achieved by the application of standard and consistent identification, enumeration, and data-processing techniques. The resulting species composition data are voluminous and present a broad picture of the phytoplankton assemblage. Our data base has enabled us to assess the long-term floristic changes, knowledge of which is lacking in the Great Lakes. The species composition reflects more or less the current trophic status of these lakes. The preponderance of nannoplankton and phytoflagellates is the subject of our current experimental research, which includes the fractionation of chlorophyll a and carbon-14 uptake, toxicity studies of heavy metals upon various size fractions of algae, and the role of microalgae and ultraplankton in the transfer of contaminants via zooplankton grazing. The need for phycological research in the Great Lakes is expanding with decreasing eutrophication and the increasing problems of contaminants. The recovery, rehabilitation, and preservation of these vital freshwaters are the primary concern of the continuing Canadian research program in the Great Lakes.

scholarly journals Factors promoting larch dominance in central Siberia: fire versus growth performance and implications for carbon dynamics at the boundary of evergreen and deciduous conifers

2012 ◽  
Vol 9 (4) ◽  
pp. 1405-1421 ◽  
Author(s):  
E.-D. Schulze ◽  
C. Wirth ◽  
D. Mollicone ◽  
N. von Lüpke ◽  
W. Ziegler ◽  
...  
Keyword(s):  
Species Composition ◽  
Plant Diseases ◽  
Yenisei Ridge ◽  
Stem Volume ◽  
Pinus Sibirica ◽  
Taiga Zone ◽  
Eastern Siberia ◽  
Central Siberia ◽  
Canopy Species

Abstract. The relative role of fire and of climate in determining canopy species composition and aboveground carbon stocks were investigated. Measurements were made along a transect extending from the dark taiga zone of central Siberia, where Picea and Abies dominate the canopy, into the Larix zone of eastern Siberia. We test the hypotheses that the change in canopy species composition is based (1) on climate-driven performance only, (2) on fire only, or (3) on fire-performance interactions. We show that the evergreen conifers Picea obovata and Abies sibirica are the natural late-successional species both in central and eastern Siberia, provided there has been no fire for an extended period of time. There are no changes in performance of the observed species along the transect. Fire appears to be the main factor explaining the dominance of Larix and of soil carbon. Of lesser influence were longitude as a proxy for climate, local hydrology and active-layer thickness. We can only partially explain fire return frequency, which is not only related to climate and land cover, but also to human behavior. Stand-replacing fires decreased from 300 to 50 yrs between the Yenisei Ridge and the upper Tunguska. Repeated non-stand-replacing surface fires eliminated the regeneration of Abies and Picea. With every 100 yrs since the last fire, the percentage of Larix decreased by 20%. Biomass of stems of single trees did not show signs of age-related decline. Relative diameter increment was 0.41 ± 0.20% at breast height and stem volume increased linearly over time with a rate of about 0.36 t C ha−1 yr−1 independent of age class and species. Stand biomass reached about 130 t C ha−1(equivalent to about 520 m3 ha−1). Individual trees of Larix were older than 600 yrs. The maximum age and biomass seemed to be limited by fungal rot of heart wood. 60% of old Larix and Picea and 30% of Pinus sibirica trees were affected by stem rot. Implications for the future role of fire and of plant diseases are discussed.

Canopy species composition drives seasonal soil characteristics in a Mediterranean riparian forest

2021 ◽  
Author(s):  
María Esther Pérez-Corona ◽  
María del Carmen Pérez-Hernández ◽  
Silvia Medina-Villar ◽  
Enrique Andivia ◽  
Francisco Bermúdez de Castro
Keyword(s):  
Species Composition ◽  
Riparian Forest ◽  
Soil Characteristics ◽  
Canopy Species

scholarly journals Factors promoting larch dominance in Eastern Siberia: fire versus growth performance and implications for carbon dynamics

2012 ◽  
Vol 9 (1) ◽  
pp. 21-62
Author(s):  
E.-D. Schulze ◽  
C. Wirth ◽  
D. Mollicone ◽  
N. von Lüpke ◽  
W. Ziegler ◽  
...  
Keyword(s):  
Species Composition ◽  
Plant Diseases ◽  
Yenisei Ridge ◽  
Stem Volume ◽  
Active Layer Thickness ◽  
Pinus Sibirica ◽  
Taiga Zone ◽  
Eastern Siberia ◽  
Age Related ◽  
Canopy Species

Abstract. The relative roles of fire and climate in determining canopy species composition and aboveground carbon stocks were investigated. Measurements were made along a transect extending from the dark taiga zone of Central Siberia, where Picea and Abies dominate the canopy, into the Larix zone of Eastern Siberia. We test the hypotheses that the change in canopy species composition is based (1) on climate-driven performance only, (2) on fire only, or (3) on fire-performance interactions. We show that the evergreen conifers Picea obovata and Abies sibirica are the natural late-successional species both in Central and Eastern Siberia, provided there has been no fire for an extended period of time. There are no changes in the climate-driven performance of the observed species. Fire appears to be the main factor explaining the dominance of Larix. Of lesser influence were longitude, hydrology and active-layer thickness. Stand-replacing fires decreased from 300 to 50 yr between the Yenisei Ridge and the upper Tunguska. Repeated non-stand-replacing surface fires eliminated the regeneration of Abies and Picea. With every 100 yr since the last fire, the percentage of Larix decreased by 20 %. Biomass of stems of single trees did not show signs of age-related decline. Relative diameter increment was 0.41 ± 0.20 % at breast height and stem volume increased linearly over time with a rate of about 0.36 t C ha−1 yr−1 independent of age class and species. Stand volumes reached about 130 t C ha−1 (equivalent to about 520 m3 ha−1). Individual trees of Larix were older than 600 yr. The maximum age and biomass seemed to be limited by fungal rot of heart wood. 60 % of old Larix and Picea and 30 % of Pinus sibirica trees were affected by stem rot. Implications for the future role of fire and of plant diseases are discussed.

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