title: Legacy of Pre-Disturbance Spatial Pattern Determines Early Structural Diversity following Severe Disturbance in Montane Spruce Forests.
abstract: BACKGROUND
  Severe canopy-removing disturbances are native to many temperate forests and radically alter stand structure, but biotic legacies (surviving elements or patterns) can lend continuity to ecosystem function after such events. Poorly understood is the degree to which the structural complexity of an old-growth forest carries over to the next stand. We asked how pre-disturbance spatial pattern acts as a legacy to influence post-disturbance stand structure, and how this legacy influences the structural diversity within the early-seral stand.
  
  
  METHODS
  Two stem-mapped one-hectare forest plots in the Czech Republic experienced a severe bark beetle outbreak, thus providing before-and-after data on spatial patterns in live and dead trees, crown projections, down logs, and herb cover.
  
  
  RESULTS
  Post-disturbance stands were dominated by an advanced regeneration layer present before the disturbance. Both major species, Norway spruce (Picea abies) and rowan (Sorbus aucuparia), were strongly self-aggregated and also clustered to former canopy trees, pre-disturbance snags, stumps and logs, suggesting positive overstory to understory neighbourhood effects. Thus, although the disturbance dramatically reduced the stand's height profile with ~100% mortality of the canopy layer, the spatial structure of post-disturbance stands still closely reflected the pre-disturbance structure. The former upper tree layer influenced advanced regeneration through microsite and light limitation. Under formerly dense canopies, regeneration density was high but relatively homogeneous in height; while in former small gaps with greater herb cover, regeneration density was lower but with greater heterogeneity in heights.
  
  
  CONCLUSIONS
  These findings suggest that pre-disturbance spatial patterns of forests can persist through severe canopy-removing disturbance, and determine the spatial structure of the succeeding stand. Such patterns constitute a subtle but key legacy effect, promoting structural complexity in early-seral forests as well as variable successional pathways and rates. This influence suggests a continuity in spatial ecosystem structure that may well persist through multiple forest generations.
authors.affiliation: Department of Forest Ecology, Faculty of Forestry and Wood science, Czech University of Life Sciences, Prague, Czech Republic.
authors.forename: Radek
authors.initials: R
authors.lastname: Bače
authors.affiliation: Department of Forest Ecology, Faculty of Forestry and Wood science, Czech University of Life Sciences, Prague, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Svoboda
authors.affiliation: Department of Forest Ecology, Faculty of Forestry and Wood science, Czech University of Life Sciences, Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Janda
authors.affiliation: Department of Forest Ecology, Faculty of Forestry and Wood science, Czech University of Life Sciences, Prague, Czech Republic.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Morrissey
authors.affiliation: Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic; Department of Applied Geoinformatics and Spatial Planning, Faculty of Environmental Sciences, Czech University of Life Sciences, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Wild
authors.affiliation: Department of Forest Ecology, Faculty of Forestry and Wood science, Czech University of Life Sciences, Prague, Czech Republic.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Clear
authors.affiliation: Department of Forest Ecology, Faculty of Forestry and Wood science, Czech University of Life Sciences, Prague, Czech Republic.
authors.forename: Vojtěch
authors.initials: V
authors.lastname: Čada
authors.affiliation: Department of Forest Ecology, Faculty of Forestry and Wood science, Czech University of Life Sciences, Prague, Czech Republic; Washington State Department of Natural Resources, Olympia, Washington, United States of America.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Donato
mesh_terms: D044822:Biodiversity; D017753:Ecosystem; D065928:Forests; D028222:Picea / Q000033:anatomy & histology / Q000145:classification / Q000254:growth & development* / Q000502:physiology; D012038:Regeneration; D062206:Spatial Analysis