Detecting fragmentation of cover in desert grasslands using line intercept

R. O. Kuehl, Mitchel McClaran, J. Van Zee

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Changes in the amount or spatial distribution of grass plants are thought to be indicative of the stability of desert grasslands. This study assessed, through simulation, the sensitivity of statistical properties for distance between plants (fetch length), measured with a line intercept transect, to changes in the spatial distribution and amount of plant cover. Monitoring plots, 30 × 30 m, were simulated for 1, 2.5, 5, 10 and 15% grass cover with random and fragmented spatial distribution. Fetch lengths were measured on 2 randomly placed 30 m transects. In addition to the median and interquartile range, the asymmetry of the sampling distributions was measured with a ratio [(maximum-median)/(median-minimum)] that would identify the presence of at least 1 large open space. The accuracy of the fetch length method was confirmed by the similarity of its sampling distribution to that for the well known random point-to-plant sampling procedure. In both the fetch length and the point-to-plant measures, the median and interquartile range increased with decreasing cover for random and fragmented distribution. The asymmetry estimate increased sharply with increasing cover for the fragmented distribution but asymmetry was nearly constant with increasing cover for the random distribution. The results suggest that the evaluation of changes over time at a monitoring site could use fetch lengths measured along a line intercept transect to detect changes in both absolute and spatial arrangement of cover.

Original languageEnglish (US)
Pages (from-to)61-66
Number of pages6
JournalJournal of Range Management
Volume54
Issue number1
StatePublished - 2001

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fetch
deserts
fragmentation
desert
grasslands
grassland
asymmetry
line transect
spatial distribution
sampling
grass
grasses
monitoring
open space
ground cover plants
transect
distribution
simulation

Keywords

  • Fetch length
  • Monitoring
  • Simulation

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Ecology

Cite this

Detecting fragmentation of cover in desert grasslands using line intercept. / Kuehl, R. O.; McClaran, Mitchel; Van Zee, J.

In: Journal of Range Management, Vol. 54, No. 1, 2001, p. 61-66.

Research output: Contribution to journalArticle

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