{"title":"Analysis adapted from text mining quantitively reveals abrupt and gradual plant-community transitions after fire in sagebrush steppe","authors":"","doi":"10.1007/s10980-024-01824-0","DOIUrl":null,"url":null,"abstract":"<h3>Abstract</h3> <span> <h3>Context</h3> <p>Plant communities vary both abruptly and gradually over time but differentiating between types of change can be difficult with existing classification and ordination methods. Structural topic modeling (STRUTMO), a text mining analysis, offers a flexible methodology for analyzing both types of temporal trends.</p> </span> <span> <h3>Objectives</h3> <p>Our objectives were to (1) identify post-fire dominant sagebrush steppe plant association types and ask how they vary with time at a landscape (multi-fire) scale and (2) ask how often major association changes are apparent at the plot-level scale.</p> </span> <span> <h3>Methods</h3> <p>We used STRUTMO and plant species cover collected between 2002–2022 across six large burn areas (1941 plots) in the Great Basin, USA to characterize landscape change in dominant plant association up to 14 years post-fire. In a case study, we assessed frequency of large annual changes (≥ 10% increase in one association and decrease in another) between associations at the plot-level scale.</p> </span> <span> <h3>Results</h3> <p>STRUTMO revealed 10 association types dominated by either perennial bunchgrasses, mixed perennial or annual grasses and forbs, or exotic annual grasses. Across all study fires, associations dominated by large-statured perennial bunchgrasses increased then stabilized, replacing the Sandberg bluegrass (<em>Poa secunda</em>)-dominated association. The cheatgrass (<em>Bromus tectorum</em>)-dominant association decreased and then increased. At the plot-level, bidirectional changes among associations occurred in ~ 75% of observations, and transitions from annual invaded to perennial associations were more common than the reverse.</p> </span> <span> <h3>Conclusions</h3> <p>The analysis revealed that associations dominated by some species (i.e. crested wheatgrass, <em>Agropyron cristatum</em>, Siberian wheatgrass, <em>Agropyron fridgida</em>, or medusahead, <em>Taeniatherum caput-medusae</em>) were more stable than associations dominated by others (i.e. Sandberg bluegrass or cheatgrass). Strong threshold-like transitions were not observed at the multi-fire scale, despite frequent ephemeral plot-level changes.</p> </span>","PeriodicalId":54745,"journal":{"name":"Landscape Ecology","volume":"16 1","pages":""},"PeriodicalIF":4.0000,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Landscape Ecology","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.1007/s10980-024-01824-0","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Context
Plant communities vary both abruptly and gradually over time but differentiating between types of change can be difficult with existing classification and ordination methods. Structural topic modeling (STRUTMO), a text mining analysis, offers a flexible methodology for analyzing both types of temporal trends.
Objectives
Our objectives were to (1) identify post-fire dominant sagebrush steppe plant association types and ask how they vary with time at a landscape (multi-fire) scale and (2) ask how often major association changes are apparent at the plot-level scale.
Methods
We used STRUTMO and plant species cover collected between 2002–2022 across six large burn areas (1941 plots) in the Great Basin, USA to characterize landscape change in dominant plant association up to 14 years post-fire. In a case study, we assessed frequency of large annual changes (≥ 10% increase in one association and decrease in another) between associations at the plot-level scale.
Results
STRUTMO revealed 10 association types dominated by either perennial bunchgrasses, mixed perennial or annual grasses and forbs, or exotic annual grasses. Across all study fires, associations dominated by large-statured perennial bunchgrasses increased then stabilized, replacing the Sandberg bluegrass (Poa secunda)-dominated association. The cheatgrass (Bromus tectorum)-dominant association decreased and then increased. At the plot-level, bidirectional changes among associations occurred in ~ 75% of observations, and transitions from annual invaded to perennial associations were more common than the reverse.
Conclusions
The analysis revealed that associations dominated by some species (i.e. crested wheatgrass, Agropyron cristatum, Siberian wheatgrass, Agropyron fridgida, or medusahead, Taeniatherum caput-medusae) were more stable than associations dominated by others (i.e. Sandberg bluegrass or cheatgrass). Strong threshold-like transitions were not observed at the multi-fire scale, despite frequent ephemeral plot-level changes.
期刊介绍：
Landscape Ecology is the flagship journal of a well-established and rapidly developing interdisciplinary science that focuses explicitly on the ecological understanding of spatial heterogeneity. Landscape Ecology draws together expertise from both biophysical and socioeconomic sciences to explore basic and applied research questions concerning the ecology, conservation, management, design/planning, and sustainability of landscapes as coupled human-environment systems. Landscape ecology studies are characterized by spatially explicit methods in which spatial attributes and arrangements of landscape elements are directly analyzed and related to ecological processes.
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