The spatial distribution of termites in shortgrass steppe: a geostatistical approach

Abstract

The broad-scale distribution of subterranean termites (Reticulitermestibialis) was studied in a shortgrass-steppe ecosystem in northern Colorado, United States. Termite occurrence and abundance was measured over 4 months at 10-m intervals along a 900-m transect that spanned a topographic gradient. Geostatistics were used to model the probability of termite occurrence along the transect, and to identify the distributional extent and potential roles of termites in shortgrass steppe. Semivariance was calculated between sample pairs of differing distances and kriging was used to interpolate the probability of termite occurrence along the transect. The semivariogram showed spatial dependence in termite distribution between samples 10-330 m apart and converged on the population variance at distances >330 m, which suggested that spatial dependence explained much of the broad-scale variation in termite distribution. A relatively large nugget variance, however, indicated there was spatial dependence below the 10-m sampling resolution. Termites were most frequently found on a south-facing slope and in a lowland swale. Four-wing saltbush (Atriplexcanescens) was also common in these areas and is important in the production of woody litter. The distribution of termites was significantly associated with proximity to saltbush, which showed a strong spatial dependence at scales <500 m. Kriged probabilities of occurrence and cross-correlation between termites and shrubs showed that peak termite occurrence was shifted upslope 100 m from areas of closest shrub proximity. Other factors, such as soil temperature, texture, or organic matter, are therefore likely to influence termite distributions in shortgrass steppe. The geostatistical approach used here provides a basis for further study on termites in shortgrass steppe, where their roles in decomposition and nutrient cycling are unknown. Geostatistics could also be used to describe distribution patterns on other soil arthropods sampled from traps or soil cores along transects that span topographic or land-use changes.

Spatial Variability and Vitality of Epigeous Termite Mounds in Pastures of Mato Grosso Do Sul, Brazil

“…These authors analyzed mound distribution patterns as a function of size and vitality, and although they used other methods and studied other species than in the present study, they also observed no spatial dependence of mound distribution in most plots. Crist (1998) also applied geostatistical techniques to study termites, but focused on individuals attracted by bait rather than epigeous mounds. As in the present study, the author also reported random distribution in termite mounds.…”

“…Clark and Evans (1954) and later, Korb and Linsenmair (2001), evaluated spatial variability by a distance index using the nearest-neighbor technique. Geostatistical techniques were applied by Crist (1998) to assess the spatial distribution of subterranean termites, and more recently, Grohmann et al (2010) analyzed mound distribution using Ripley's K function, pair correlation function and similar techniques, to analyze mound distribution patterns of a fungusgrowing termite species.…”

Stability of the spatio-temporal distribution and niche overlap in neotropical earthworm assemblages

“…The spatial distribution of different taxa of soil biota has especially been addressed during the last decade (Adams 1998, Bigwood and Inouye 1988, Boag et al 1994, Crist and Wiens 1996, Crist 1998, Fromm et al 1993, Nuutinen 1998, Poier and Richter 1992, Robertson 1994, Robertson and Freckman 1995, Rossi 2003a, b, c, Rossi et al 1995, Stein et al 1992, Wallace and Hawkins 1994.…”

Monitoring Land Use and Land Cover Effects on Water Quality in Cheung Ek Lake using ASTER Images

“…Then, ordinary kriging was used to estimate the spatial distribution of water parameters within the target lake. The semivariance value was defined as below equation (Crist, 1998;Kawamura et al, 2009;Lim et al, 2012;Webster, 1985):…”