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Full-Text Articles in Life Sciences
Yponomeuta Evonymellus Outbreaks In Southern Finland: Spatial Synchrony But Different Local Magnitudes, Brian J. Wilsey, Conchita Alonso, Timo Vuorisalo, Tuija Honkanen
Yponomeuta Evonymellus Outbreaks In Southern Finland: Spatial Synchrony But Different Local Magnitudes, Brian J. Wilsey, Conchita Alonso, Timo Vuorisalo, Tuija Honkanen
Brian J. Wilsey
Defoliations of Prunus padus by Yponomeuta evonymellus were monitored in two areas in southern Finland. During a long-term study (1980–1995) in the area with high peak defoliations, P. padus trees recorded two defoliation peaks, leading to complete defoliation of many trees. The negative relationship between pupal mass and current year tree defoliation during the peak years suggested shortage of food affected reproductive potential of Y. evonymellus. Furthermore, no delayed induced resistance was observed in these populations. Interannual correlations in degrees of defoliation experienced by individual trees were low, i.e. high defoliation in one year did not predict the degree of …
Biodiversity And Ecosystem Functioning: Importance Of Species Evenness In An Old Field, Brian J. Wilsey, Catherine Potvin
Biodiversity And Ecosystem Functioning: Importance Of Species Evenness In An Old Field, Brian J. Wilsey, Catherine Potvin
Brian J. Wilsey
Changes in land use, habitat fragmentation, nutrient enrichment, and environmental stress often lead to reduced plant diversity in ecosystems. However, it remains controversial whether these reductions in diversity will affect energy flow and nutrient cycling. Diversity has two components: species richness, or the number of plant species in a given area, and species evenness, or how well distributed abundance or biomass is among species within a community. We experimentally varied species evenness and the identity of the dominant plant species in an old field of Quebec to test whether plant productivity would increase with increasing levels of evenness, and whether …
Effects Of Resource Availability On Carbon Allocation And Developmental Instability In Cloned Birch Seedlings, Brian J. Wilsey, Janne H. Lappalainen, Jocelyn Martel, Kyösti Lempa, Vladimir Ossipov
Effects Of Resource Availability On Carbon Allocation And Developmental Instability In Cloned Birch Seedlings, Brian J. Wilsey, Janne H. Lappalainen, Jocelyn Martel, Kyösti Lempa, Vladimir Ossipov
Brian J. Wilsey
Abundant nitrogen improves seedling growth and establishment. Vigorous growth brings about changes in rates and patterns of plant development and changes in the relationship between primary and secondary metabolism, which may make seedlings more susceptible to herbivores and pathogens than are slow-growing seedlings. We studied how nitrogen fertilization and manual defoliation of source leaves affect growth, carbon allocation, and developmental instability in cloned seedlings of white birch (Betula pubescens Ehrh.). Biomass was higher, whereas concentrations of most classes of phenolic compounds were lower in the nitrogen-rich environment. Interestingly, fertilization did not change the concentrations of cell wall–bound proanthocyanidins, which represent …