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Climate models project that by 2100, the northeastern US and eastern Canada will warm by approximately 35 °C, with increased winter precipitation. These changes will affect trees directly and also indirectly through effects on 'nuisance' species, such as insect pests, pathogens, and invasive plants. We review how basic ecological principles can be used to predict nuisance species' responses to climate change and how this is likely to impact northeastern forests. We then examine in detail the potential responses of two pest species (hemlock woolly adelgid (Adelges tsugae Annand) and forest tent caterpillar (Malacosoma disstria Hubner)), two pathogens (armillaria root rot (Armillaria spp.) and beech bark disease (Cryptococcus fagisuga Lind. + Neonectria spp.)), and two invasive plant species (glossy buckthorn (Frangula alms Mill.) and oriental bittersweet (Celastrus orbiculatus Thunb.)). Several of these species are likely to have stronger or more widespread effects on forest composition and structure under the projected climate. However, uncertainty pervades our predictions because we lack adequate data on the species and because some species depend on complex, incompletely understood, unstable relationships. While targeted research will increase our confidence in making predictions, some certainty will always persist. Therefore, we encourage policies that allow for this uncertainty by considering a avide range of possible scenarios. Les modeles climatiques prevoient des temperatures 3-5°C plus elevees et des precipitations hivernales plus abondantes vers 2100 dans le nord-est des Etats-Unis et l'est du Canada. Ces changements affecteront les arbres directement et indirectement via leurs effets sur des especes nuisibles telles que les insectes ravageurs, les agents pathogenes et les plantes invasives. Nous passons en revue la facon dont les principes ecologiques peuvent etre utilises pour predire la reaction des especes nuisibles aux changements climatiques et la facon dont cela pourrait affecter les forets du nordest. Nous etudions ensuite en detail les reactions potentielles de deux insectes ravageurs : le puceron lanigere de la pruche (Adelges tsugae Armand) et la livree des forets (Malacosoma disstria Hunner), deux agents pathogenes : le pourridie agaric (Armillaria spp.) et la maladie corticale du hetre (Cryptococcus fagisuga Lind. + Neonectria spp.) et deux especes de plantes invasives : le nerprun bourdaine (Frangula alnus Mill.) et la celastre asiatique (Celastrus orbiculatus Thunb.). Plusieurs de ces especes auront probablement des effets plus prononces ou plus etendus sur la composition et la structure de la foret dans les conditions climatiques anticipees. Cependant, nos predictions demeurent incertaines a cause du manque de donnees adequates sur ces especes et parce que certaines especes dependent de relations complexes, peu connues et instables. La recherche orientee nous permettra de faire des predictions avec une plus grande confiance, mais il restera toujours une certaine incertitude. Par consequent, nous encourageons les politiques qui tiennent compte de cette incertitude en considerant une vaste gamme de scenarios potentiels. [Traduit par la Redaction], Introduction In northeastern North America, forests host a variety of native and introduced insect pests, invasive plant species, and pathogens (which we collectively term 'nuisance species') that currently affect forest [...]

At Discovery Bay, Jamaica,Tripneustes ventricosuslives in beds of the turtle grassThalassia testudinum. Especially during daylight hours, it covers its aboral surface with fragments of this plant and other objects. Normally pigmented, wild-type sea urchins covered themselves significantly less withThalassiawhen sunlight was experimentally decreased to 66% or 32% ambient intensity. Consistent with this result, naturally occurring sea urchins exhibited significantly less covering at a deep (3.5 m) site than at a shallow (1 m) site, where light intensities at the bottom were 619 and 946 µmol s-1 m-2, respectively. The graded covering response to light intensity suggests that covering is a defense against damaging solar radiation. Albino sea urchins covered themselves significantly more withThalassiathan wild-type sea urchins in both full and 66% sunlight. In addition, at the shallow site where they accounted for about 4% of the population, they showed significantly greater covering than wild-type urchins. The greater covering response of albino sea urchins suggests a greater susceptibility to solar radiation. [ABSTRACT FROM AUTHOR]