skip to main content

Search for: All records

Creators/Authors contains: "Turner, Monica G."

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Many natural disturbances have a strong climate forcing, and concern is rising about how ecosystems will respond to disturbance regimes to which they are not adapted. Novelty can arise either as attributes of the disturbance regime (e.g., frequency, severity, duration) shift beyond their historical ranges of variation or as new disturbance agents not present historically emerge. How much novelty ecological systems can absorb and whether changing disturbance regimes will lead to novel outcomes is determined by the ecological responses of communities, which are also subject to change. Powerful conceptual frameworks exist for anticipating consequences of novel disturbance regimes, but these remain challenging to apply in real-world settings. Nonlinear relationships (e.g., tipping points, feedbacks) are of particular concern because of their disproportionate effects. Future research should quantify the rise of novelty in disturbance regimes and assess the capacity of ecosystems to respond to these changes. Novel disturbance regimes will be potent catalysts for ecological change. Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 54 is November 2023. Please see for revised estimates. 
    more » « less
    Free, publicly-accessible full text available November 2, 2024
  2. Free, publicly-accessible full text available June 1, 2024
  3. Summary

    Climate change is driving changes in disturbance regimes world‐wide. In forests adapted to infrequent, high‐severity fires, recent anomalously short fire‐return intervals (FRIs) have resulted in greatly reduced postfire tree regeneration. However, effects on understory plant communities remain unexplored.

    Understory plant communities were sampled in 31 plot pairs across Greater Yellowstone (Wyoming, USA). Each pair included one plot burned at high severity twice in < 30 yr and one plot burned in the same most recent fire but not burned previously for > 125 yr. Understory communities following short‐interval fires were also compared with those following the previous long‐interval fire.

    Species capable of growing in drier conditions and in lower vegetation zones became more abundant and regional differences in plant communities declined following short‐interval fire. Dissimilarity between plot pairs increased in mesic settings and decreased with time since fire and postfire winter snowfall. Reduced postfire tree density following short‐interval fire rather than FRIper seaffected the occurrence of most plant species.

    Anomalously short FRIs altered understory plant communities in space and time, with some indications of community thermophilization and regional homogenization. These and other shifts in understory plant communities may continue with ongoing changes in climate and fire across temperate forests.

    more » « less
  4. Abstract

    As 21st‐century climate and disturbance dynamics depart from historic baselines, ecosystem resilience is uncertain. Multiple drivers are changing simultaneously, and interactions among drivers could amplify ecosystem vulnerability to change. Subalpine forests in Greater Yellowstone (Northern Rocky Mountains, USA) were historically resilient to infrequent (100–300 year), severe fire. We sampled paired short‐interval (<30‐year) and long‐interval (>125‐year) post‐fire plots most recently burned between 1988 and 2018 to address two questions: (1) How do short‐interval fire, climate, topography, and distance to unburned live forest edge interact to affect post‐fire forest regeneration? (2) How do forest biomass and fuels vary following short‐interval versus long‐interval severe fires? Mean post‐fire live tree stem density was an order of magnitude lower following short‐interval versus long‐interval fires (3240 vs. 28,741 stems ha−1, respectively). Differences between paired plots were amplified at longer distances to live forest edge. Surprisingly, warmer–drier climate was associated with higher seedling densities even after short‐interval fire, likely relating to regional variation in serotiny of lodgepole pine (Pinus contortavar.latifolia). Unlike conifers, density of aspen (Populus tremuloides), a deciduous resprouter, increased with short‐interval versus long‐interval fires (mean 384 vs. 62 stems ha−1, respectively). Live biomass and canopy fuels remained low nearly 30 years after short‐interval fire, in contrast with rapid recovery after long‐interval fire, suggesting that future burn severity may be reduced for several decades following reburns. Short‐interval plots also had half as much dead woody biomass compared with long‐interval plots (60 vs. 121 Mg ha−1), primarily due to the absence of large snags. Our results suggest differences in tree regeneration following short‐interval versus long‐interval fires will be especially pronounced where serotiny was high historically. Propagule limitation will also interact with short‐interval fires to diminish tree regeneration but lessen subsequent burn severity. Amplifying driver interactions are likely to threaten forest resilience under expected trajectories of a future fire.

    more » « less
  5. Abstract Asian pheretimoid earthworms of the genera Amynthas and Metaphire (jumping worms) are leading a new wave of coinvasion into Northeastern and Midwestern states, with potential consequences for native organisms and ecosystem processes. However, little is known about their distribution, abundance, and habitat preferences in urban landscapes—areas that will likely influence their range expansion via human-driven spread. We led a participatory field campaign to assess jumping worm distribution and abundance in Madison, Wisconsin, in the United States. By compressing 250 person-hours of sampling effort into a single day, we quantified the presence and abundance of three jumping worm species across different land-cover types (forest, grassland, open space, and residential lawns and gardens), finding that urban green spaces differed in invasibility. We show that community science can be powerful for researching invasive species while engaging the public in conservation. This approach was particularly effective in the present study, where broad spatial sampling was required within a short temporal window. 
    more » « less
  6. Abstract

    Subalpine forests that historically burned every 100–300 yr are expected to burn more frequently as climate warms, perhaps before trees reach reproductive maturity or produce a serotinous seedbank. Tree regeneration after short‐interval (<30‐yr) high‐severity fire will increasingly rely on seed dispersal from unburned trees, but how dispersal varies with age and structure of surrounding forest is poorly understood. We studied wind dispersal of three conifers (Picea engelmannii,Abies lasiocarpa, andPinus contortavar.latifolia, which can be serotinous and nonserotinous) after a stand‐replacing fire that burned young (≤30 yr) and older (>100 yr)P. contortaforest in Grand Teton National Park (Wyoming, USA). We asked how propagule pressure varied with time since last fire, how seed delivery into burned forest varied with age and structure of live forest edges, what variables explained seed delivery into burned forest, and how spatial patterns of delivery across the burned area could vary with alternate patterns of surrounding live forest age. Seeds were collected in traps along 100‐m transects (n = 18) extending from live forest edges of varying age (18, 30, and >100 yr) into areas of recent (2‐yr) high‐severity fire, and along transects in live forests to measure propagule pressure. Propagule pressure was low in 18‐yr‐old stands (~8 seeds/m2) and similarly greater in 30‐ and 100‐yr‐old stands (~32 seeds/m2). Mean dispersal distance was lowest from 18‐yr‐old edges and greatest from >100‐yr‐old edges. Seed delivery into burned forest declined with increasing distance and increased with height of trees at live forest edges, and was consistently higher forP. contortathan for other conifers. Empirical dispersal kernels revealed that seed delivery from 18‐yr‐old edges was very low (≤2.4 seeds/m2) and concentrated within 10 m of the live edge, whereas seed delivery from >100‐yr‐old edges was >4.9 seeds/m2out to 80 m. When extrapolated throughout the burned landscape, estimated seed delivery was low (<49,400 seeds/ha) in >70% of areas that burned in short‐interval fire (<30 yr). As fire frequency increases, immaturity risk will be compounded in short‐interval fires because seed dispersal from surrounding young trees is limited.

    more » « less
  7. null (Ed.)
  8. Forest dynamics arise from the interplay of environmental drivers and disturbances with the demographic processes of recruitment, growth, and mortality, subsequently driving biomass and species composition. However, forest disturbances and subsequent recovery are shifting with global changes in climate and land use, altering these dynamics. Changes in environmental drivers, land use, and disturbance regimes are forcing forests toward younger, shorter stands. Rising carbon dioxide, acclimation, adaptation, and migration can influence these impacts. Recent developments in Earth system models support increasingly realistic simulations of vegetation dynamics. In parallel, emerging remote sensing datasets promise qualitatively new and more abundant data on the underlying processes and consequences for vegetation structure. When combined, these advances hold promise for improving the scientific understanding of changes in vegetation demographics and disturbances. 
    more » « less