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News from the National Science Foundation
Other Media
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Chronic Nitrogen Enrichment Slows Fungal Action | Ecology
 Fungi, often spotted in cold, damp locations, are responsible for decomposing the plant litter that falls to forest floors, enriching soils. Without fungi, dead plant material would inundate ecosystems and overwhelm other organisms. What would happen, then, if anthropogenic nitrogen altered the fungi’s ability to perform this vital ecosystem function? A recent study capitalized on a 28-year nitrogen enrichment experiment at the Harvard Forest LTER site in north-central Massachusetts to find out. As nitrogen inputs to a system increase, researchers found, fungal decomposition slowed.
Using a control population of fungi and a population that was exposed to excess nitrogen over the past 28 years, the study compared the growth rates and decomposition ability of both populations in a control and nitrogen-enriched scenario. Changes in the growth rate of fungi were inconclusive, increasing in some cases and decreasing in others. However, fungi from nitrogen-enriched plots decayed leaf litter more slowly than those from control plots (regardless of the treatment they received), as did fungi from control plots that were transplanted to nitrogen-enriched plots.
Further, researchers found that when exposed to elevated levels of nitrogen, fungi quickly speciate from the original population. This is significant because even if anthropogenic nitrogen inputs decrease, the speciation of fungi, and resulting decreased decomposition capacity, would linger. In this way, the evolution of fungi will likely shape ecosystem processes as nitrogen inputs grow.
—Alina Werth
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Sustainability in the City | Landscape Ecology
 Ecosystem services, such as the water cycle or flood control, support urban sustainability but are also impacted by the development of city-centers. Improving the sustainable design and management of cities, then, requires understanding how development affects such processes and services. A recent study contrasted two methods for measuring urban sustainability, ecology in cities and ecology of cities, and found that the integrative framework of ecology of cities more thoroughly addresses sustainability and its three components: the environment, economy, and society.
For years, ecologists measured differences in land use type and cover as black or white, natural or unnatural. This paradigm, known as ecology in cities, supports a very narrow view of sustainability. It focuses on the persistence and viability of “natural” patches, which addresses only a single pillar of sustainability, the environment, and fails to acknowledge the coexistence of natural and built environments, such as street trees lining a paved city sidewalk.
The ecology of cities paradigm, however, recognizes such gray areas where vegetation, permeable pavement, and impermeable pavement persist together. Ecology of cities allows for a more inclusive view of sustainability that recognizes societal and economic needs as well as environmental. For example, the ecology of cities paradigm recognizes the value of shade from street trees and tree’s interaction with the water cycle. These elements of sustainability go overlooked under the ecology in cities paradigm, which highlights that sustainability measurement has big implications for implementation.
—Alina Werth
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How Will Climate Change Affect Peak Firefly Activity? | Royal Society Open Science
 A typical warm summer night is complemented with the familiar glow of fireflies and the light spectacle they create darting around and lighting up the night sky. However, the timing of these light shows might be affected by environmental changes. In order to better understand the life history of the firefly, researchers from the Kellogg Biological Station (KBS) LTER investigated the phenological patterns of fireflies from 2004-2015 to determine what explains the variability observed in their mating season.
From long term weather and insect trap datasets, the researchers determined that temperature accumulation was the primary driver of phenology, with peak activity occurring around 800 degree-days (base 10°C). However, there was variation in the timing of peak activity, which was explained by changes in precipitation. In years with precipitation extremes, the mating season was delayed.
Warming temperatures and changes in precipitation patterns clearly have the potential to disrupt firefly phenology. Climate-change driven asynchronies also add the possibility of decoupling with other related systems, which can have community-wide consequences. Shifts in adult activity probably mirror shifts in larvae development, which could lead to a potential mismatch between the larvae and their food source, where resource availability is an important determinant of future mating success. Additionally, firefly larvae and other predaceous beetles are known to have a dramatic effect on the establishment of agricultural pests in the growing season, so an asynchrony could lead to an increase in agricultural pests.
—Erin O'Reilly
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Invasive Earthworms and Their Effects on Midwestern Soils | Biological Invasions
 As ecosystem dynamics change with warming global temperatures, researchers have begun investigating the potential of further northward invasions from nonnative species like the Asian earthworm. Past studies have shown that nonnative earthworms can significantly alter ecosystem functioning, and this experiment confirms that Asian earthworms can do as much—if not more—damage as their better-researched European counterparts.
After the appearance of an Asian jumping worm population in Wisconsin, researchers performed both a soil core experiment and in-field testing for both prairie and forest ecosystems. Using sites in the Northern Temperate Lakes region, they found that the presence of two Asian earthworm species not only reduced leaf litter biomass but also enriched soil nutrient pools.
As earthworms convert organic material into more rapidly mobile forms, their presence in soil systems could lead to a flush and overall loss of nutrients. Effectively, this means that earthworm invasions could act as catalysts of ecosystem wide changes, with effects cascading up the food chain.These findings may become increasingly applicable to management decisions as climate change opens these valuable forest and prairie ecosystems to settlement by invasive species.
—Madison Harris
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Decomposition in Streams: A Global Synthesis | Global Change Biology
A major multi-site analysis of leaf litter decomposition in streams and rivers found that rising temperatures are unlikely to speed decomposition as much as predicted under metabolic theory. Although fresh water bodies cover only three percent of the Earth’s land surface, they are a key component of the global carbon and nutrient cycles and the rate of decomposition in streams affects both carbon dioxide emissions and supply of organic matter to downstream food webs.
Leaves, twigs and other organic materials fall into streams, where grazers and microbes break them down into fine particles and convert them to organic carbon and carbon dioxide. Those processes all operate a bit faster at warmer temperatures, so ecologists have predicted that a changing climate would speed decomposition. The questions is: by how much?
The study, published this month in Global Change Biology and led by Jennifer Follstad Shah at the University of Utah, was a highly collaborative effort drawing on over a thousand cases from 169 separate studies. Researchers examined the influence of latitude, litter quality, plant genera, detritivore density, and other factors on the temperature sensitivity of decomposition. Other factors often seemed to outweigh the response to temperature, especially in temperate biomes, where litter supply is episodic and communities may be adapted to respond quickly even in cold conditions. Based on a 1-4 degree C increase in temperature—and accounting for all the factors they examined—the study found that litter breakdown would be accelerated only about half as much as metabolic theory predicts. —Marty Downs
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NSF
NSF has issued updated guidance on public access to data and publications. In general, existing data management plans continue to apply. Publications resulting from grants submitted after January 2016 must be deposited in NSF’s Public Access Repository (NSF-PAR)
NEON
Interested in National Ecological Observatory Network (NEON) field site data? Go to http://neondata.org to download data and explore (1) an interactive data product catalog (2) a data availability viewer to quickly see what data are available from which sites and 3) a data API to programmatically access NEON data. You can also request remote sensing data or NEON specimen and samples. NEON currently provides partial data from 66 sites.
SESYNC
SESYNC will host a nine-day short course August 15 - 25 covering basic principles of using Bayesian models to gain insight from data.
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New LTER Sites Announced
The LTER Network is growing! The National Science Foundation awarded three new sites this spring. Two are in areas with highly productive fisheries: Northern Gulf of Alaska (NGA), Northeast U.S. Shelf (NES). A third will focus on dynamics of melting sea ice: Beaufort Lagoon Ecosystems (BLE).
A Sad Farewell
The Network lost a committed scientist and educator this week, with the death of Art Schwartzchild from the Virginia Coast Reserve LTER. This 2008 video interview offers a reminder of Art’s voice, energy, and creativity—which will be sorely missed at VCR and across the Network.
Jobs
Urban Resilience to Extremes (UREx) Sustainability Research Network (SRN), Education Program Coordinator
Regional Conservation Communicator for the Wildlands and Woodlands project at Harvard Forest LTER, MA
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