DOI: 10.5061/dryad.z612jm6jq
title: Data from: Multi-decadal vegetation transformations of a New Mexico ponderosa pine landscape after severe fires and aerial seeding

description: Wildfires and climate change are having transformative effects on
 vegetation composition and structure, and post-fire management may have
 long-lasting impacts on ecosystem reorganization. Post-fire aerial seeding
 treatments are commonly used to reduce runoff and soil erosion, but little
 is known about how seeding treatments affect native vegetation recovery
 over long periods of time, particularly in type-converted forests which
 have been dramatically transformed by the effects of repeated,
 high-severity fire. In this study, we analyze and report on a rare
 long-term (23-year) dataset that documents vegetation dynamics following a
 1996 post-fire aerial seed treatment and subsequent 2011 high-severity
 reburn in a dry conifer forest of northern New Mexico in the southwestern
 United States. Repeated surveys between 1997 – 2019 of 49 permanent
 transects were used to test for differences in vegetation cover, richness,
 and diversity between seeded and unseeded areas, and to characterize the
 development of seeded and unseeded vegetation communities through time and
 across gradients of burn severity, elevation, and soil-available water
 capacity. Post-fire seeding led to a clear and sustained divergence in
 herbaceous community composition. Seeded plots had much higher cover of
 non-native graminoids, primarily Bromus inermis, a likely contaminant in
 the seed mix. High-severity reburning in all plots in 2011 reduced native
 graminoid cover by half at seeded plots compared to both pre-fire levels
 and to plots that were unseeded following the initial 1996 fire. In
 addition, increased fire severity was associated with increased non-native
 graminoid cover and reduced native graminoid cover, native species
 richness, and species diversity.   This study documents
 a fire-driven ecosystem transformation from a former conifer forest into a
 shrub-grass system, reinforced by aerial seeding of grasses and
 high-severity reburning. This unique long-term dataset illustrates that
 post-fire seeding carries significant risk of unwanted non-native species
 invasions that persist through subsequent fires – indicating that
 alternative post-fire management actions merit consideration to better
 support native ecosystem resilience in the face of emergent climate change
 and increasing disturbance. Lastly, this study highlights the importance
 of long-term monitoring of post-fire vegetation dynamics, as short-term
 assessments will miss key elements of the full complexity of ecosystem
 responses to fire and post-fire management actions.
description: The vegetation data collection method followed the line-intercept
 method (Mueller-Dombois and Ellenberg 1974). Vegetation transects were
 approximately 50 meters in length and the data collected included
 herbaceous foliar and basal cover of all live and dead vegetation to the
 nearest cm. Plants were identified to the species-level, when possible,
 otherwise plants were grouped by their genus, or unknown plants were
 grouped by their growth form (see below). This line intercept method
 records the number of canopy-cover centimeters per species, and therefore
 allows for overlapping total vegetative canopy cover more than the total
 transect length. In cases where combined canopy cover for an individual
 species exceeded 100%, these species values were constrained to 100%.
 Canopy cover is reported as a proportion of the number of centimeters
 recording live foliar cover of a given species or growth form relative to
 the length of the transect. Bare ground is reported as a proportion of
 exposed soil, measured as the basal gap area between plant bases or other
 objects embedded in the surface (e.g., logs, rocks, litter) relative to
 the length of the transect.
description: # Data from: Multi-decadal vegetation transformations of a New Mexico
 ponderosa pine landscape after severe fires and aerial seeding
 ## Description of the data
 and file structure These data represent 4 samples of a 22 year time
 period: repeat observations of vegetation cover from the Dome Wilderness
 in New Mexico, from 1997-2019. Fundamentally, these data represent species
 and ground cover at a cm-resolution, recorded along 50 meter line
 intercept transects. The description of column names are as follow:
 Transect: Site ID Year: Sample ID Code: 4-5 character code relating to
 species or ground cover category RevBI: Burn Severity Index as reported by
 initial BAER estimates TRT: Treatment - seeded or unseeded Full_name:
 Latin name of species or genus, or full name of ground cover category
 Origin: Native or Non-native to the Dome Wilderness, NA for ground cover
 categories Transect_cm: Total length of the Transect in centimeters
 Growth_form: Functional group of plant species, genus, or cover category.
 Abbreviations are as follow: B - Bare Ground, C - Crypotgram, F- Forbs, G
 - Graminoids, L - Litter, M - Mushroom or Fungus, S - Shrub, T - Tree, U -
 SubShrub PctC: Percent canopy cover of total transect, rounded to nearest
 1% PctC_basal: Percent cover of basal intersection with transect, as
 opposed to canopy interception (representing a base of an individual plant
 or otherwise any object embedded in the soil surface) Total_cm: Combined
 basal and canopy cover of cover type on transect/year combination
 Basal_cm: Basal intersection (embedded in the soil) of cover type on
 transect/year combination Canopy_cm: Canopy intersection of cover type on
 transect/year combination\ FS_BAND: A factor, indicating the land
 management agency which administers the plot. Either FS - for Forest
 Service, or BAND for Bandelier National Monument (National Park Service)
 The vegetation data collection method followed the line-intercept method
 (Mueller-Dombois and Ellenberg 1974). Vegetation transects were
 approximately 50 meters in length and the data collected included
 herbaceous foliar and basal cover of all live and dead vegetation to the
 nearest cm. Plants were identified to the species-level, when possible,
 otherwise plants were grouped by their genus, or unknown plants were
 grouped by their growth form (see below). This line intercept method
 records the number of canopy-cover centimeters per species, and therefore
 allows for overlapping total vegetative canopy cover more than the total
 transect length. In cases where combined canopy cover for an individual
 species exceeded 100%, these species values were constrained to 100%.
 Canopy cover is reported as a proportion of the number of centimeters
 recording live foliar cover of a given species or growth form relative to
 the length of the transect. Bare ground is reported as a proportion of
 exposed soil, measured as the basal gap area between plant bases or other
 objects embedded in the surface (e.g., logs, rocks, litter) relative to
 the length of the transect.