Research

The Nutrient Network (NutNet): a global research cooperative

Global environmental impacts require global-scale research efforts. The Nutrient Network is a globally-distributed, massively collaborative, experiment replicated at more than 70 sites in 12 countries on 5 continents to investigate the impacts of some of the most globally-pervasive impacts of humans on biological systems: eutrophication of earth’s ecosystems, biological invasions, and species extinctions. Specifically, the Nutrient Network has been using an unprecedented replicated experiment to understand the role of anthropogenic nutrient addition (nitrogen, phosphorus, potassium, and other micronutrients) and loss of large herbivores on important issues including invasive species, global biodiversity, ecosystem functioning, and disease (Firn et al. 2010; Adler et al. 2011; Stokstad 2011). While the current investigations are globally critical, perhaps the most important contribution of the network is experimental infrastructure that is allowing us to generate informed predictions about the responses of ecological systems to these current human impacts.

Note that reprints are provided solely for single-user, noncommercial use.

The Community Ecology of Disease

Disease ecology has grown rapidly as a field, but only recently have models and studies expanded to address the full community context of host-pathogen interactions. Nonetheless, most hosts are limited by multiple resources and are affected by multiple pathogens, while most pathogens are host-generalists. Only a few researchers currently are addressing the complex interactions among abiotic resources, host communities, and pathogen communities. In part, this is because many human and animal disease systems are experimentally intractable for logistical and ethical reasons (see Borer et al. 2011). In collaboration withElizabeth Borer and researchers at other Universities (Andy Dobson, Kevin Gross,Charles Mitchell, and Sunny Power), we are using a complex, experimentally tractable, host-pathogen community to investigate a wide range of basic and applied questions about the community ecology of disease (Borer et al. 2007;Borer et al. 2009; Seabloom et al. 2009; Borer et al. 2010; Seabloom et al. 2010). Our study system is a suite of aphid-vectored RNA viruses that comprise one of the most commercially important and widespread plant pathogen groups (barley and cereal yellow dwarf viruses).

Note that reprints are provided solely for single-user, noncommercial use.

Effects of Consumers and Nutrients on Marine, Aquatic, and Terrestrial Ecosystems

The supply of resources and the impacts of consumers are two of the most important general factors governing the diversity and productivity of earth’s ecosystems. I have been working with a collaborative group of marine, aquatic, and terrestrial ecologists to assemble a large data set of composed of data from published experiments manipulating resources (e.g., nitrogen and phosphorus) and herbivores. In a series of meta-analyses, we have examined the effects of consumer and resources on plant community diversity, productivity, and structure of plant and herbivore communities (e.g., Shurin et al. 2002; Borer et al. 2005; Borer et al. 2006; Elser et al. 2007; Hillebrand et al. 2007; Hillebrand et al. 2009; Harpole et al. 2011).

Note that reprints are provided solely for single-user, noncommercial use.

The Invasion and restoration of California grasslands

Invasive species pose one of the most serious threats to global biodiversity and cost hundreds of billions of dollars annually in the United State alone. Since 1997, I have been investigating one of the most dramatic and persistent plant invasions worldwide, the conversion of 9.2 million ha of California from native-perennial to exotic-annual grassland. Historically, the presumption has been that dominance by exotic annuals was due to their competitive superiority. However, using a series of large field experiments, my collaborators (especially Stan Harpole) and I demonstrated that native perennials were superior resource competitors, and that exclusion of the native perennial grasses was a case of long-term transience driven by regional-scale seed limitation and interactions with viral pathogens and native vertebrate consumers (Seabloom et al. 2003;Borer et al. 2007; Seabloom 2011). From the applied perspective, this work suggests that adding native perennial grass seed may be sufficient to reestablish viable populations of these grasses in California.

Note that reprints are provided solely for single-user, noncommercial use.

Beachgrass Invasion, Coastal Geomorphology, and Coastal Protection

While plant invasions can threaten native plants and animals, cause economic damage, and change ecosystem processes, it seems far-fetched that they may alter the very shape of the Earth’s surface and alter the security of cities and towns. However, in a unique setting, this seems to be the case. In collaborative work with Sally Hacker, Peter Ruggiero, Phoebe Zarnetske, I am investigating the effect of two invading grasses on the US West Coast. Observational studies I conducted in 1987 suggested that an invasive grass may have reduced the coastal dune height by 50 percent (Seabloom and Wiedemann. 1994). We are expanding on this work to isolate the mechanisms underlying the relationship between dune height and species invasion, as well as the potential for increased risk to coastal communities from tsunamis and flooding (Hacker et al. 2011;Zarnetske et al. 2011).