Geology topics

Ryan Kelly

Publications and source records attributed to Ryan Kelly.

3 recordsLinked to original sources

USGS2023

Toward a national eDNA strategy for the United States

Environmental DNA (eDNA) data make it possible to measure and monitor biodiversity at unprecedented resolution and scale. As use-cases multiply and scientific consensus grows regarding the value of eDNA analysis, public agencies have an opportunity to decide how and where eDNA data fit into their mandates. Within the United States, many federal and state agencies are individually using eDNA data in various applications and developing relevant scientific expertise. A national strategy for eDNA implementation would capitalize on recent scientific developments, providing a common set of next-generation tools for natural resource management and public health protection. Such a strategy would avoid patchwork and possibly inconsistent guidelines in different agencies, smoothing the way for efficient uptake of eDNA data in management. Because eDNA analysis is already in widespread use in both ocean and freshwater settings, we focus here on applications in these environments. However, we foresee the broad adoption of eDNA analysis to meet many resource management issues across the nation because the same tools have immediate terrestrial and aerial applications.

Environmental DNA↗

USGS2017

A model-based approach to wildland fire reconstruction using sediment charcoal records

Lake sediment charcoal records are used in paleoecological analyses to reconstruct fire history, including the identification of past wildland fires. One challenge of applying sediment charcoal records to infer fire history is the separation of charcoal associated with local fire occurrence and charcoal originating from regional fire activity. Despite a variety of methods to identify local fires from sediment charcoal records, an integrated statistical framework for fire reconstruction is lacking. We develop a Bayesian point process model to estimate the probability of fire associated with charcoal counts from individual-lake sediments and estimate mean fire return intervals. A multivariate extension of the model combines records from multiple lakes to reduce uncertainty in local fire identification and estimate a regional mean fire return interval. The univariate and multivariate models are applied to 13 lakes in the Yukon Flats region of Alaska. Both models resulted in similar mean fire return intervals (100–350 years) with reduced uncertainty under the multivariate model due to improved estimation of regional charcoal deposition. The point process model offers an integrated statistical framework for paleofire reconstruction and extends existing methods to infer regional fire history from multiple lake records with uncertainty following directly from posterior distributions.

Environmetrics↗

USGS2015

Palaeodata-informed modelling of large carbon losses from recent burning of boreal forests

Wildfires play a key role in the boreal forest carbon cycle 1 , 2 , and models suggest that accelerated burning will increase boreal C emissions in the coming century 3 . However, these predictions may be compromised because brief observational records provide limited constraints to model initial conditions 4 . We confronted this limitation by using palaeoenvironmental data to drive simulations of long-term C dynamics in the Alaskan boreal forest. Results show that fire was the dominant control on C cycling over the past millennium, with changes in fire frequency accounting for 84% of C stock variability. A recent rise in fire frequency inferred from the palaeorecord 5 led to simulated C losses of 1.4   kg   C   m −2 (12% of ecosystem C stocks) from 1950 to 2006. In stark contrast, a small net C sink of 0.3   kg   C   m −2 occurred if the past fire regime was assumed to be similar to the modern regime, as is common in models of C dynamics. Although boreal fire regimes are heterogeneous, recent trends 6 and future projections 7 point to increasing fire activity in response to climate warming throughout the biome. Thus, predictions 8 that terrestrial C sinks of northern high latitudes will mitigate rising atmospheric CO 2 may be over-optimistic.

Nature Climate Change↗