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Jeannine Cavender-Bares
Professor, University of Minnesota
Understanding Drivers and Consequences of Plant Diversity Across Temporal and Spatial Scales in an Era of Rapid Global Change
Abstract: Advancing our understanding of the causes and consequences of biodiversity and its change through time is critical to sustaining our life support systems. Using a series of empirical systems—including model clades, large datasets, field observations and manipulative experiments—in conjunction with molecular, ecophysiological and spectroscopic methods that enable integration of biological processes across spatial and temporal scales, I reveal a series of insights on the factors that drive community assembly and influence ecosystem function. Within the oaks (Quercus spp), convergence in the two broadly distributed clades—which underwent parallel sympatric adaptive radiation and diversified into ecological habitats associated with variation in life-history strategies—explains how they became a dominant and hyperdiverse clade on the North American continent. Expanding diseases such as the oak wilt fungus (Bretziella fagacearum), however, threaten to radically change these forests. Spectroscopic technologies enable study of these threats to and changes in ecosystems in more detail and at broader spatial extents than ever before possible. In two forest diversity experiments, spectral approaches using airborne spectroscopy accurately detect the effects of biodiversity on productivity, providing insight into its underlying drivers. Differences between the spectral reflectance of monocultures and mixed species stands enable us to spectrally quantify net biodiversity effects on productivity and on canopy nitrogen, and the method can be applied at large spatial scales. The extent to which such data can enhance study of belowground soil and microbial processes is not well understood. In grassland systems, aboveground vegetation quantity and quality are known to influence belowground microbial processes and nutrient cycling. In two grassland biodiversity experiments, ecosystem productivity, and the chemical, structural and phylogenetic-functional composition of plant communities are tightly coupled to soil inputs that drive microbial processes belowground such that vegetation chemistry and productivity, as detected from airborne sensors, predicts belowground soil processes. I will explain how these varied studies highlight the potential of botanical and fungal collections—in combination with emerging technologies and large data streams—to contribute to critical biodiversity knowledge in an era of rapid change.