Abstract. The objective of this study was to quantitatively describe vegetation‐environment relationships at a regional scale within the Province of New Brunswick, Canada, using vegetation and environment data from 3947 provincial forestry sample plots. The major plant community types in the province were identified using cluster analysis. Relationships of these communities to climate, topography and soil variables were analyzed by Canonical Correspondence Analysis (CCA), using both a reduced data set consisting of cluster likelihood scores × sample plots and an unreduced species × sample plots data matrix. The vegetation types and major axes of environmental variation were mapped to examine the geographic distributions of these factors within the province. Eight communities were identified and described in terms of enhanced/reduced species (significantly higher or lower frequencies of occurrence in a specific community type relative to all plots) and common species (species in the community type with the highest frequencies of occurrence). The canonical axes explained 25 % of the variation in the vegetation cluster data. Vegetation composition was related to three major environmental gradients representing climate and elevation, soil moisture, and soil fertility. The geographic distributions of vegetation communities exhibited predictable but weak correspondence to the geographic distributions of individual environmental factors. Our findings emphasize the overriding importance of climate and topography and the secondary importance of soil factors in controlling vegetation pattern at the regional scale.

The importance of biodiversity has become widely recognized but the best methods for conserving forest biodiversity are still being debated. Central to this debate is the influence of plantations and managed stands on local and landscape-scale biodiversity. A recent paper by Erdle and Pollard in The Forestry Chronicle (2002), which concluded that few plantations are strict monocultures in terms of the total number of tree species, could be interpreted as making the case that plantations have relatively minor consequences for biodiversity. We argue that: (1) it is not only the number of species, but also the identities and relative abundances of species that are of ecological importance, and (2) defining biodiversity in terms of tree species alone is of limited applicability. Existing research in New Brunswick on the impact of plantations on biodiversity at the stand scale reveals potentially significant biodiversity losses, at least in certain taxa. The proposal that incorporating more structural elements (e.g., snags, coarse woody debris, vertical structure) and retaining greater tree species diversity to ameliorate negative consequences of plantations remains a hypothesis to be tested in this region. Scientific information gathered in the following areas will allow better decision making: (1) to what degree are older plantations used by native species? (2) are productivity and survivorship of vertebrates in intensively managed stands similar to those in unmanaged forest? (3) are intensively managed stands suitable habitat for non-vertebrates? (4) are there thresholds in the response of some species to landscape-scale habitat loss caused by intensive forest management?Key words: plantations, biodiversity, species composition, landscape scale, stand structures RÉSUMÉ L'importance de la biodiversité est acceptée de façon générale mais les meilleures méthodes de conservation de la biodiversité forestière font encore l'objet d'un débat. Au coeur de celui-ci, on retrouve l'influence des plantations et des peuplements aménagés sur la biodiversité locale et à l'échelle de l'écosystème. Un article récent publié par Erdle et Pollard dans Le Forestry Chronicle en 2002 qui concluait que rares sont les plantations qui constituent des monocultures absolues en terme du nombre total d'espèces d'arbres, pouvait être interprété comme énonçant que les plantations entraînent des conséquences relativement mineures au niveau de la biodiversité. Nous alléguons que (1) ce n'est pas seulement le nombre d'espèces, mais également l'identité et l'abondance relative des espèces qui sont d'importance écologique et, (2) la défini-tion de la biodiversité en terme d'espèces d'arbres seulement est d'une applicabilité restreinte. Les recherches en cours au Nouveau-Brunswick sur les retombées des plantations sur la biodiversité au niveau du peuplement révèlent des pertes de biodiversité potentiellement significatives, du moins pour certains taxons. La proposition cherchant à incorporer plus d'éléments structuraux (par ex., les chicots, l...

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The wellbeing, socio-economic viability and the associated health of the inhabitant species of any ecosystem are largely dependent on the quality of its water resources. In this regard, we developed a protocol to measure the potential impact of various environmental and anthropogenic factors on runoff quality at 22 water sampling sites across the Bumbu Watershed in Papua New Guinea. For this purpose, we utilized Digital Elevation Models and several GIS techniques for delineation of stream drainage patterns, classification of the watershed based on Land Use/Land Cover, spatial interpolation of rainfall patterns and computation of the corresponding factor runoff. Our study concludes that a variety of potential challenges to surface water quality are possible such as natural geologic and geochemical inputs, runoff accumulation of precipitation and organic matter pollutants. The developed protocol can also accommodate socio-economic factors such as community and household health, sanitation and hygiene practices, pollution and waste disposal. This research lays the foundation for further development of an all-inclusive correlational analysis between the relative importance values of the factors influencing runoff and spatially distributed water quality measurements in the Bumbu basin.

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