Patterns, Mechanisms, and Characterization of Carbon Cycling Stability Following Partial Forest Disturbance

Among the most essential questions in the era of climate change is how the forest carbon (C) cycle will respond to an increase in the extent of biotic disturbances from insects and pathogens. While research has focused on stand-replacing disturbance regimes, less is known about C cycling stability following partial disturbances that produce gradients of disturbance severity. Belowground C cycling responses to disturbance are especially poorly understood, even though temperate forest soils contain up to 50% of total ecosystem C and soil respiration (Rs) accounts for more than half of temperate forest C loss. Interpreting trends and mechanisms of C cycling disturbance response requires the integration of cross-scaled experiments and refined ecological theory. The overarching goal of my dissertation is to lay a foundation for the use of a multi-dimensional stability framework for the C cycling community, and through manipulative ecosystem experiments, assess patterns and advance mechanistic understanding of how partial disturbances impact forest C cycling. Synthesizing across chapters, I highlight three overarching conclusions from my dissertation. First, leveraging components of a multi-dimensional stability framework into assessments of C flux disturbance response revealed the utility of applying such a framework to analyses of ecosystem function. Second, Rs can exhibit variable responses to the same partial disturbance. Third, temperate forests can sustain C balance following disturbances across a gradient of severities, suggesting these forests can be highly functionally resistant to the increasing threat of forest disturbances from insect pests and pathogens

The status of Fraxinus americana and the effect of emerald ash borer infestation on forest succession on UMBS property.

General EcologyThe Emerald Ash Borer infestation is causing widespread mortality i n Fraxinus spp, across the US. We measured the health status of Fraxinus americana on UMBS property and surveyed the understory composition to estimate what might su cceed in the canopy gaps of this species. We also surveyed the current overstory composition and compared our data to Pearsall's overstory survey from the 1980s to get a baseline of h ow the overstory on UMBS property has changed over time due to natural forest succession. We found mostly in significant change in overstory composition and abundance from Pearsall's data to our current data, showing the slow and non linear process of natural forest succession. However, in three of our plots, we found significant difference, which shows some tum over from early to later succession species. To predict h ow the overstory will change after the succession due to loss of the Fraxinus americana, we used the species with the highest relative abundance in the understory as our predicted succession species. We found that Acer saccharum and Fagus grandifolia are the most likely succession species. Since the decimation of F. americana due to this invasive pest will happen relatively quickly, it could accelerate the rate of succession on UMBS property. Since EAB is affecting millions of Fraxinus trees around the country, more baseline surveys like this need to done to determine how forests will change to do the loss of this species. More research should also be done to study the ecological role of Fraxinus and how their loss will be impacting different ecosystems.http://deepblue.lib.umich.edu/bitstream/2027.42/136112/1/Mathes_Kayla_2016.pd

COSORE: A community database for continuous soil respiration and other soil‐atmosphere greenhouse gas flux data

Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil‐to‐atmosphere CO2 flux, commonly though imprecisely termed soil respiration (RS), is one of the largest carbon fluxes in the Earth system. An increasing number of high‐frequency RS measurements (typically, from an automated system with hourly sampling) have been made over the last two decades; an increasing number of methane measurements are being made with such systems as well. Such high frequency data are an invaluable resource for understanding GHG fluxes, but lack a central database or repository. Here we describe the lightweight, open‐source COSORE (COntinuous SOil REspiration) database and software, that focuses on automated, continuous and long‐term GHG flux datasets, and is intended to serve as a community resource for earth sciences, climate change syntheses and model evaluation. Contributed datasets are mapped to a single, consistent standard, with metadata on contributors, geographic location, measurement conditions and ancillary data. The design emphasizes the importance of reproducibility, scientific transparency and open access to data. While being oriented towards continuously measured RS, the database design accommodates other soil‐atmosphere measurements (e.g. ecosystem respiration, chamber‐measured net ecosystem exchange, methane fluxes) as well as experimental treatments (heterotrophic only, etc.). We give brief examples of the types of analyses possible using this new community resource and describe its accompanying R software package

Disturbance- accelerated succession increases the production of a temperate forest

Many secondary deciduous forests of eastern North America are approaching a transition in which mature early- successional trees are declining, resulting in an uncertain future for this century- long carbon (C) sink. We initiated the Forest Accelerated Succession Experiment (FASET) at the University of Michigan Biological Station to examine the patterns and mechanisms underlying forest C cycling following the stem girdling- induced mortality of >6,700 early- successional Populus spp. (aspen) and Betula papyrifera (paper birch). Meteorological flux tower- based C cycling observations from the 33- ha treatment forest have been paired with those from a nearby unmanipulated forest since 2008. Following over a decade of observations, we revisit our core hypothesis: that net ecosystem production (NEP) would increase following the transition to mid- late- successional species dominance due to increased canopy structural complexity. Supporting our hypothesis, NEP was stable, briefly declined, and then increased relative to the control in the decade following disturbance; however, increasing NEP was not associated with rising structural complexity but rather with a rapid 1- yr recovery of total leaf area index as mid- late- successional Acer, Quercus, and Pinus assumed canopy dominance. The transition to mid- late- successional species dominance improved carbon- use efficiency (CUE = NEP/gross primary production) as ecosystem respiration declined. Similar soil respiration rates in control and treatment forests, along with species differences in leaf physiology and the rising relative growth rates of mid- late- successional species in the treatment forest, suggest changes in aboveground plant respiration and growth were primarily responsible for increases in NEP. We conclude that deciduous forests transitioning from early to middle succession are capable of sustained or increased NEP, even when experiencing extensive tree mortality. This adds to mounting evidence that aging deciduous forests in the region will function as C sinks for decades to come.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/170208/1/eap2417_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/170208/2/eap2417-sup-0001-AppendixS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/170208/3/eap2417.pd

Enabling FAIR data in Earth and environmental science with community-centric (meta)data reporting formats.

Research can be more transparent and collaborative by using Findable, Accessible, Interoperable, and Reusable (FAIR) principles to publish Earth and environmental science data. Reporting formats-instructions, templates, and tools for consistently formatting data within a discipline-can help make data more accessible and reusable. However, the immense diversity of data types across Earth science disciplines makes development and adoption challenging. Here, we describe 11 community reporting formats for a diverse set of Earth science (meta)data including cross-domain metadata (dataset metadata, location metadata, sample metadata), file-formatting guidelines (file-level metadata, CSV files, terrestrial model data archiving), and domain-specific reporting formats for some biological, geochemical, and hydrological data (amplicon abundance tables, leaf-level gas exchange, soil respiration, water and sediment chemistry, sensor-based hydrologic measurements). More broadly, we provide guidelines that communities can use to create new (meta)data formats that integrate with their scientific workflows. Such reporting formats have the potential to accelerate scientific discovery and predictions by making it easier for data contributors to provide (meta)data that are more interoperable and reusable

COSORE: A community database for continuous soil respiration and other soil-atmosphere greenhouse gas flux data.

Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil-to-atmosphere CO2 flux, commonly though imprecisely termed soil respiration (RS ), is one of the largest carbon fluxes in the Earth system. An increasing number of high-frequency RS measurements (typically, from an automated system with hourly sampling) have been made over the last two decades; an increasing number of methane measurements are being made with such systems as well. Such high frequency data are an invaluable resource for understanding GHG fluxes, but lack a central database or repository. Here we describe the lightweight, open-source COSORE (COntinuous SOil REspiration) database and software, that focuses on automated, continuous and long-term GHG flux datasets, and is intended to serve as a community resource for earth sciences, climate change syntheses and model evaluation. Contributed datasets are mapped to a single, consistent standard, with metadata on contributors, geographic location, measurement conditions and ancillary data. The design emphasizes the importance of reproducibility, scientific transparency and open access to data. While being oriented towards continuously measured RS , the database design accommodates other soil-atmosphere measurements (e.g. ecosystem respiration, chamber-measured net ecosystem exchange, methane fluxes) as well as experimental treatments (heterotrophic only, etc.). We give brief examples of the types of analyses possible using this new community resource and describe its accompanying R software package