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The protection of ecological functions of forested swamps and peatlands is the subject of legal and regulatory measures. In Quebec and elsewhere in Canada, wood harvesting is carried out on swamps and peatlands of merchantable forests. What is the impact of forestry practices on these wetlands hydrological functions such as sediment retention, groundwater recharge, flood reduction and low flow augmentation? The answer to this question is complex as the contribution of wetlands to these hydrological functions vary with each wetland type as underlined by the experts. With the aim of ascertaining the contribution of wetlands, and to infer the effects of forest management on forested swamps and peatlands, we carried out a literature review. The existing literature reviews only partially cover the subject or in the case of peatlands, they mainly consider drained sites. In this review, the links between the hydrologic functions and forest harvesting are treated by category of wetlands to take into account their anticipated specific contribution.
Many studies over the past 50 years have sought to identify environmental factors influencing breeding duck abundance and distribution in northern North America. Because results are currently scattered within the scientific literature, a summary of established duck-habitat associations would help to orientate future modelling research. Our goal was to review the published research testing for duck-habitat associations in northern North America. We reviewed 124 studies, summarizing their geographical coverage and species representation, and then analyzing the duck-habitat associations they tested. We identified 533 associations on 133 covariates falling into 16 environmental classes. Covariates of the ‘wetland' classes were the most frequently associated with ducks; among these, ‘wetland area' and ‘wetland density' were the most common. ‘Climate’ covariates were the second most common associations, suggesting the potential for projecting the effects of climate change on ducks. The best-documented anthropogenic class was ‘agriculture’, for which associations with ducks were mostly negative. However, relatively few studies tested for associations with covariates for anthropogenic disturbances, which suggests that more research is needed to support forecasts of duck distribution under future human activity. This review and the accompanying database of duck-habitat associations will support future modelling studies by facilitating the selection of suitable habitat covariates.
To meet the need for wood in the African savanna zone, forest plantations have been established since the 1930s. Exotic tree species of the genera Pinus and Eucalyptus are the major groups planted in the Western Highlands of Cameroon where they form artificial forests whose mycoflora is not yet documented. This study aimed at comparing the macro-fungi diversity in mature eucalyptus and pine plantations in tropical savannas, particularly in the Melap Forest Reserve. Four permanent plots of 1000 m2 were installed in each plant community, sporophores were collected and identified from April to June 2016; species richness and generic diversity were calculated. A total of 125 species were inventoried. Taxonomic diversity was significantly higher in Eucalyptus communities than in Pinus communities, with 107 and 33 species respectively. The number of ectomycorrhizal species was higher in the eucalyptus plots where a few locally consumed species were found. The mycofloral abundance in Eucalyptus communities is explained by the presence of local tree species hosting ectomycorrhizal fungi, such as Uapaca guineensis.
Plains bison (Bison bison bison) are suspected to have played an important role in maintaining and structuring the plant communities throughout the Aspen Parkland. We examine the effects of a fenced bison herd on grassland plant communities in Riding Mountain National Park, Manitoba, Canada. We focus on the relationship between bison and woody plant encroachment along the forest-grassland ecotone, and on the effects that short- and long-term occupation by bison have on Festuca hallii grassland communities including the effects of bison reintroduction to a grassland area ungrazed by bison for 165 years. We found limited impacts of bison on the shrub community at the forest grassland edge. Bison rarely entered areas with dense, tall shrub understories, and thus bison cannot be a major factor controlling the ecotone. Shrub stem mortality due to fire may be a necessary precursor to bison effectively mitigating woody encroachment in the Aspen Parkland. We found limited short-term impacts of bison on grassland communities, with reduced sward heights but no change in composition. The long-term (>80 year) presence of bison was associated with greater species richness, reduced litter accumulation, and a distinct plant community composition compared to areas without bison impacts.
Estimating the resilience time of an ecosystem may lead to different values depending on the compartment or function of interest and the measurement method. We sought to estimate the resilience of a cork oak (Quercus suber L.) stand – a typical west Mediterranean forest type – 8 years after a wildfire, using three independent indicators. Each represents a function or a characteristic of the ecosystem: (i) the Normalized Difference Vegetation Index (NDVI), a remote sensing-based proxy of photosynthetic activity, (ii) the vegetation profile, based on an estimation of the vegetation cover at different heights above ground, and (iii) the avifauna composition, a component of animal biodiversity. The NDVI seems to have recovered a value close to its pre-fire value about 9 years after the fire. Recovering a vertical vegetation profile similar to that before the fire requires a longer time, tentatively estimated to not less than a dozen years. Recovery of the pre-fire avifauna is likely to require an even longer time, which could not be estimated from our 8-year monitoring period. The indicator based on avifauna appears to be the most discriminating indicator, among the three compared here, for estimating the time required for full recovery of the ecosystem over the long term.
Passive transport has likely contributed to the post-glacial dispersal of species in temperate regions. However, identifying such processes from patterns can be obscured by confounding environmental conditions. We studied the distribution of ground beetles in Ontario's Far North, a vast (450,000 km2) and largely intact region, to identify mechanisms that aid in species dispersal when confounding factors, such as temperature, are controlled. We tested a model of passive, riverine dispersal using recent records of flightless and flighted ground beetles from 34 sites across the region. The number of species declined with distance from main watershed rivers, as predicted from our model at the site level. Contrary to expectations, this pattern was evident with flighted species but not flightless species. The opposite pattern, with flightless species displaying a decrease with increasing distance from river, was evident at a regional level. These patterns are consistent with ground beetles carried along rivers since glacial retreat. We surmise that northward dispersal of these invertebrates into the boreal forest has been aided by vegetation and other debris flowing down rivers, including soil from eroded banks in which larvae and pupae reside. Biogeographic inferences, although often subtle, can be supported by broad-scale studies of intact landscapes.
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