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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The use of small ephemeral wetlands and streams by amphibians in the mixedwood forest of boreal Alberta

Okonkwo, Godwin Unknown Date
No description available.
2

The use of small ephemeral wetlands and streams by amphibians in the mixedwood forest of boreal Alberta

Okonkwo, Godwin 06 1900 (has links)
Identifying amphibian habitats within a landscape provides a tool for managing their populations. I identified if and how amphibians used small ephemeral wetlands (≤ 0.1ha) and streams within the mixedwood forest area managed by Daishowa Marubeni International Ltd. near Peace River, north-western Alberta. Twenty-seven wetlands and their riparian zones were sampled for all life stages of amphibians in 2008 using timed visual encounter surveys. The riparian zones of 11 small streams were sampled with pitfall traps within 120 m of their beds from 2006 to 2008. Habitat features were also measured. Lithobates sylvaticus, Anaxyrus boreas and Pseudacris maculata used small ephemeral wetlands and the riparian zones of ephemeral, intermittent and permanent streams at different life stages. Water temperature and canopy cover influenced amphibian presence and abundance in wetlands. Coniferous and deciduous tree density were associated with L. sylvaticus abundance at the stream sites. I conclude that small waterbodies are amphibian habitats in the mixedwood forest of boreal Alberta. / Ecology
3

Zhodnocení dřevinných výsadeb prováděných při revitalizacích drobných říčních toků / The evaluation of woody plantings carried out in revitalization small streams

KELLEROVÁ, Petra January 2015 (has links)
The aim of this thesis is to evaluate the success of woody plantings carried out in order to revitalize small streams. For selected restorations was assessed dendrological composition, establishment, health and care after planting. The most common species planted in the revitalization of small streams is the alder (Alnus glutinosa), a pioneer tree species reinforcing shores, to which it was coupled with flowing water home. Sometimes forming groups with gray alder (Alnus incana) but that does not fit stagnant water and silver birch (Betula pendula). Also mountain elm (Ulmus glabra) and willow species (Salix sp.) are widely planted along streams. Locally, there were planted common ash (Fraxinus excelsior) but mostly in very poor condition, and oak (Quercus robur), sporadically rowan (Sorbus aucuparia), dogwood (Swida sanquinea) and Norway maple (Acer platanoides). A statistical evaluation shows that the biggest influence on species composition and state of health of trees has the revitalization age. Also important is the care of the vegetation in later years after planting.
4

The effects of wildfire disturbance and streamside clearcut harvesting on instream wood and small stream geomorphology in south-central British Columbia

Scherer, Robert Andrew 05 1900 (has links)
Few field studies have assessed the temporal and spatial dynamics of wood in small streams (bankfull widths < 5 m) flowing through forest ecosystems dominated by stand replacing wildfires. Comparisons of instream wood loads associated with clearcut harvesting, wildfire, and undisturbed, old forests are also scarce. The two main objectives of this research were: (1) to document the temporal and spatial variability of wood and its geomorphic role in relation to stand development stage; and (2) to compare wood loads and its geomorphic role in relation to streamside clearcut harvesting, wildfires and older, undisturbed forest stands. This research focused on 38 small streams with gradients less than 14% situated in the plateau regions of south-central British Columbia, Canada. A distinct temporal trend in wood loading was observed, with elevated volumes present 30-50 years subsequent to the wildfire disturbances following a “reverse J-shaped” trend in relation to time since the last major wildfire disturbance. The number of wood pieces was highly variable and few of the wood characteristics exhibited a significant trend in relation to time since the last major wildfire disturbance. Except at the smallest spatial scale (<3 m segments longitudinally along the stream) the spatial distribution of wood followed a random pattern with no trend, indicating that wood loads are related to local wood recruitment processes associated with episodic or chronic tree mortality and low wood transport. Instream wood volumes were three times higher in streams recently (30 – 50 years ago) disturbed by wildfire as compared to the older riparian forest stands, confirming that wildfire disturbance is an important mechanism to recruit wood into streams. No significant differences in wood loads were identified between the streamside clearcut streams and the wildfire-disturbed or older, undisturbed streams. The lack of reductions in wood loads are likely related to the low transport capacity of our study streams, retention of non-merchantable trees and recruitment of slash from harvesting. A lack of morphologic variability was observed in relation to the disturbances indicating that the streams included in this study are relatively robust and unresponsive to wildfire or streamside clearcut harvesting disturbances.
5

The effects of wildfire disturbance and streamside clearcut harvesting on instream wood and small stream geomorphology in south-central British Columbia

Scherer, Robert Andrew 05 1900 (has links)
Few field studies have assessed the temporal and spatial dynamics of wood in small streams (bankfull widths < 5 m) flowing through forest ecosystems dominated by stand replacing wildfires. Comparisons of instream wood loads associated with clearcut harvesting, wildfire, and undisturbed, old forests are also scarce. The two main objectives of this research were: (1) to document the temporal and spatial variability of wood and its geomorphic role in relation to stand development stage; and (2) to compare wood loads and its geomorphic role in relation to streamside clearcut harvesting, wildfires and older, undisturbed forest stands. This research focused on 38 small streams with gradients less than 14% situated in the plateau regions of south-central British Columbia, Canada. A distinct temporal trend in wood loading was observed, with elevated volumes present 30-50 years subsequent to the wildfire disturbances following a “reverse J-shaped” trend in relation to time since the last major wildfire disturbance. The number of wood pieces was highly variable and few of the wood characteristics exhibited a significant trend in relation to time since the last major wildfire disturbance. Except at the smallest spatial scale (<3 m segments longitudinally along the stream) the spatial distribution of wood followed a random pattern with no trend, indicating that wood loads are related to local wood recruitment processes associated with episodic or chronic tree mortality and low wood transport. Instream wood volumes were three times higher in streams recently (30 – 50 years ago) disturbed by wildfire as compared to the older riparian forest stands, confirming that wildfire disturbance is an important mechanism to recruit wood into streams. No significant differences in wood loads were identified between the streamside clearcut streams and the wildfire-disturbed or older, undisturbed streams. The lack of reductions in wood loads are likely related to the low transport capacity of our study streams, retention of non-merchantable trees and recruitment of slash from harvesting. A lack of morphologic variability was observed in relation to the disturbances indicating that the streams included in this study are relatively robust and unresponsive to wildfire or streamside clearcut harvesting disturbances.
6

The effects of wildfire disturbance and streamside clearcut harvesting on instream wood and small stream geomorphology in south-central British Columbia

Scherer, Robert Andrew 05 1900 (has links)
Few field studies have assessed the temporal and spatial dynamics of wood in small streams (bankfull widths < 5 m) flowing through forest ecosystems dominated by stand replacing wildfires. Comparisons of instream wood loads associated with clearcut harvesting, wildfire, and undisturbed, old forests are also scarce. The two main objectives of this research were: (1) to document the temporal and spatial variability of wood and its geomorphic role in relation to stand development stage; and (2) to compare wood loads and its geomorphic role in relation to streamside clearcut harvesting, wildfires and older, undisturbed forest stands. This research focused on 38 small streams with gradients less than 14% situated in the plateau regions of south-central British Columbia, Canada. A distinct temporal trend in wood loading was observed, with elevated volumes present 30-50 years subsequent to the wildfire disturbances following a “reverse J-shaped” trend in relation to time since the last major wildfire disturbance. The number of wood pieces was highly variable and few of the wood characteristics exhibited a significant trend in relation to time since the last major wildfire disturbance. Except at the smallest spatial scale (<3 m segments longitudinally along the stream) the spatial distribution of wood followed a random pattern with no trend, indicating that wood loads are related to local wood recruitment processes associated with episodic or chronic tree mortality and low wood transport. Instream wood volumes were three times higher in streams recently (30 – 50 years ago) disturbed by wildfire as compared to the older riparian forest stands, confirming that wildfire disturbance is an important mechanism to recruit wood into streams. No significant differences in wood loads were identified between the streamside clearcut streams and the wildfire-disturbed or older, undisturbed streams. The lack of reductions in wood loads are likely related to the low transport capacity of our study streams, retention of non-merchantable trees and recruitment of slash from harvesting. A lack of morphologic variability was observed in relation to the disturbances indicating that the streams included in this study are relatively robust and unresponsive to wildfire or streamside clearcut harvesting disturbances. / Forestry, Faculty of / Graduate

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