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  • 1
    ISSN: 1432-1009
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Preservation of small natural areas is not in itself a sufficient measure to maintain the integrity of the ecosystems for which they were initially set aside. Intense pressure from recreational use is just one of the many human-caused stresses that may degrade natural areas. Therefore, land-use planning and management from an ecological perspective is necessary to assess, ensure, and in some cases increase, the ecological integrity of protected natural areas. An ecosystem management approach for small protected natural areas with high recreational use is presented, based on three interrelated components: an ecological evaluation procedure of ecosystems, the implementation of management interventions on ecosystems, and the development of a monitoring scheme of ecosystem components. The ecological evaluation procedure combines two concepts: the biotic value of vegetation and wildlife and the abiotic fragility of the soils. This combined evaluation process results in the creation of a sensitivity map that can be used as a management tool for planners and managers. Management interventions, the second component of the management approach, are derived from concepts of ecological succession. Intentional human interventions are used to maintain the ecological integrity of ecosystems or in some cases to restore degraded sites. For the third component, only the basic principles of the monitoring program will be discussed. A pilot project in one of the Montreal urban community protected areas is presented to illustrate aspects of the proposed ecosystem management approach.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 363 (1993), S. 353-355 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] When inhibitory synapses reform between serotonergic Retzius (R) and pressure (P) neurons of the leech in culture5'6, the excitatory extrasynaptic response to serotonin is eliminated at sites of contact7. Contact specifically with the R cell8 renders cation channels in the P cell insensitive to ...
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular neurobiology 16 (1996), S. 699-713 
    ISSN: 1573-6830
    Keywords: synapse formation ; leech neurons ; serotonin ; channel modulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. Serotonin (5-HT) modulates two different responses in the pressure sensitive neurons (P) of the leech: an inhibitory, Cl− dependent synaptic response and a depolarizing extrasynaptic response. 2. Serotonergic Retzius cells (R)in vivo and in culture elicit inhibitory Cl− dependent responses in P neurons. Moreover, at discrete sites of contact between R and P cells, the excitatory response to 5-HT is gradually lost prior to synapse formation. This phenomenon is specifically mediated by R cells. 3. The extrasynaptic response is mediated by cation channels sensitive to protein kinase C (PKC). Cation channels are present at the sites of contact but they become insensitive to PKC. Moreover, cation channels from single P cells are no longer modulated by PKC if they are inserted (by cramming the patch pipette) into the cytoplasm of a P cell in contact with an R cell. 4. Blockers of tyrosine kinases prevent the uncoupling of cation channel modulation and inhibit synapse formation between the R and the P neurons. 5. We suggest that cell contact induces an intracellular, tyrosine kinase-dependent signal as part of the mechanism of neuronal recognition leading to synapse formation.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant ecology 83 (1989), S. 209-222 
    ISSN: 1573-5052
    Keywords: Kriging ; Pattern analysis ; Reliability ; Sampling theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using spatial analysis methods such as spatial autocorrelation coefficients (Moran's I and Geary's c) and kriging, we compare the capacity of different sampling designs and sample sizes to detect the spatial structure of a sugar-maple (Acer saccharum L.) tree density data set gathered from a secondary growth forest of southwestern Québec. Three different types of subsampling designs (random, systematic and systematic-cluster) with small sample sizes (50 and 64 points), obtained from this larger data set (200 points), are evaluated. The sensitivity of the spatial methods in the detection and the reconstruction of spatial patterns following the application of the various subsampling designs is discussed. We find that the type of sampling design plays an important role in the capacity of autocorrelation coefficients to detect significant spatial autocorrelation, and in the ability to accurately reconstruct spatial patterns by kriging. Sampling designs that contain varying sampling steps, like random and systematic-cluster designs, seem more capable of detecting spatial structures than a systematic design.
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  • 5
  • 6
    Publication Date: 2004-03-01
    Description: Several xylophagous insect species have adapted to recurrent fires in boreal forests and use high-quality habitats created by these disturbances. To characterize the xylophagous insect assemblages of fire-killed black spruce and their patterns of substratum use, eighty-four 40 cm long bole segments were cut in 2000 and 2001 according to tree diameter, segment height, and fire severity criteria in a 1999 burn in the Grands-Jardins provincial park, Quebec, Canada. The segments were suspended in rearing cages, and neonates were collected until November 2001. The cerambycid Mono chamus scutellatus (Say) and the scolytids Dryocoetes affaber (Mann.) and Polygraphus rufipennis (Kirby) were the most common beetles collected. For all common taxa, more neonates emerged from larger-diameter trees. Few neonates emerged from the upper parts of the trees, and none of the species were specialist of the upper parts of the tree. Fire severity had a drastic effect, and heavily charred trees yielded very few insects. The effect of fire severity on insect colonization density varies widely among tree species. This effect may be linked to varying bark thickness and to bark's insulating potential against water loss during the fire. The host's vigor before its death, measured from growth rings of the last 10 years, had a positive effect on cerambycid emergence, but no effect on scolytids.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 7
    Publication Date: 2011-05-01
    Description: Burned forests represent high-quality habitats for many deadwood-dependent species. Yet, post-fire conditions may vary greatly within and among burns and thereby may affect habitat suitability for these species. We studied habitat selection of nesting black-backed woodpeckers ( Picoides arcticus Swainson) in recently burned spruce-dominated boreal forests. Our objectives were to (i) identify factors involved in snag selection for both nesting and foraging and (ii) examine selection of nest sites within the burned landscape. A total of 92 nests and 1612 foraging observations were used to investigate snag selection. Our results show that both pre-fire forest conditions and fire severity are important in determining the quality of burned forests for black-backed woodpeckers. This species selected large snags for both nesting (〉20 cm DBH) and foraging (〉15 cm DBH). Woodpeckers selected deciduous and degraded “pre-fire” snags for nesting whereas black spruce snags that had been created by fire and that were moderately burned were preferred for foraging. Nest sites were concentrated in burned mature stands and supported higher densities of large snags (e.g., 〉15 cm DBH). Our results suggest that burned forest patches of at least 20 ha and composed mainly of burned mature and old-growth forests should be maintained during post-fire harvesting. The decrease in the amount of late seral stands in managed forest landscapes raises concerns about the future availability of high-quality burned forests for this species.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 8
    Publication Date: 2013-05-01
    Description: Dwindling stocks of decaying coarse woody debris (CWD), as a result of forest management and growing interest for biofuels, may jeopardize the persistence of a broad spectrum of organisms such as small mammals. In this study, we quantified the effects of CWD in late-decay stages on the occupancy dynamics of small mammals in managed and unmanaged boreal forests. Probabilities of initial site occupancy, colonization, local extinction, and co-occurrence were modelled for five boreal small mammal species. Southern red-backed voles (Myodes gapperi Vigor) and southern bog lemmings (Synaptomys cooperi Baird) were more likely to occupy sites with high volumes of late-decay CWD early in the summer. The probability of local extinction for deer mice (Peromyscus maniculatus Wagner) slightly decreased with an increasing volume of late-decay CWD in harvested sites. Southern red-backed voles and meadow voles (Microtus pennsylvanicus Ord) co-occurred more often in old, uncut forests, as well as harvested sites with high volumes of late-decay CWD. These results suggest that cover provided by late-decay CWD benefited two small rodent species during early reproduction and increased persistence of deer mice later in the summer. Finally, we found that in addition to high live-tree basal areas, high late-decay CWD volume also favours local diversity of small mammals.
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    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 9
    Publication Date: 2003-01-01
    Description: We studied the spatial and temporal response of three epiphytic lichens (Bryoria spp., Evernia mesomorpha Nyl., and Usnea spp.) to edge effects in conifer forests of northwestern Quebec. Lichen abundance and substrate variables were sampled at four distances (5, 25, 50, and 100 m) from the edge in 15 edgeinterior transects in managed black spruce (Picea mariana (Mill.) BSP) forests. Responses to edge effects were assessed for short-term (13 years) and long-term (8 and 1623 years) periods. We also assessed the effect of forest fragment size on lichen abundance in 27 forest fragments ranging in size from 0.03 ha to 〉4 ha. We found a significant effect of distance to edge on mass of E. mesomorpha and Usnea spp. Lichen mass was lower in the first 50 m of edge compared with the forest interior (100 m). Size of forest fragments had no significant effect in any of the three lichens. However, mass of Usnea spp. was low in the seven smallest (
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 10
    Publication Date: 2011-03-01
    Description: Partial cuts are increasingly proposed to maintain habitats for species negatively affected by clearcutting, even if their benefits on nonpasserine birds and large mammals are still poorly documented. Our main objective was to evaluate effects of commercial thinning (CT) on spruce grouse ( Falcipennis canadensis L.), a game bird of the boreal forest. Because this species is known to be associated with a dense vegetation cover, we hypothesized that habitat use would be lower in treated sites. In spring 2006, we evaluated site occupancy in 94 forest stands (50 CT and 44 uncut stands) in Quebec by visiting each on three occasions during the breeding season (March–May). Additionally, during the molting period (May–July), we used radiotelemetry to monitor habitat use by 19 males. As compared with uncut stands, results show that a lower proportion of CTs were used in spring (39% versus 60%, after accounting for detection). During the molting period, CTs were also used less than expected according to their availability. The significant reduction of lateral and vertical forest cover in CT may explain these results. We conclude that even if CT is perceived beneficial for wildlife, it does not completely fulfill the needs of species associated with dense understory vegetation, such as spruce grouse.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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