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

Abstract

Epigeous termite mounds are frequently observed in pasture areas, but the processes regulating their population dynamics are poorly known. This study evaluated epigeous termite mounds in cultivated grasslands used as pastures, assessing their spatial distribution by means of geostatistics and evaluating their vitality. The study was conducted in the Cerrado biome in the municipality of Rio Brilhante, Mato Grosso do Sul, Brazil. In two pasture areas (Pasture 1 and Pasture 2), epigeous mounds (nests) were georeferenced and analyzed for height, circumference and vitality (inhabited or not). The area occupied by the mounds was calculated and termite specimens were collected for taxonomic identification. The spatial distribution pattern of the mounds was analyzed with geostatistical procedures. In both pasture areas, all epigeous mounds were built by the same species, Cornitermes cumulans. The mean number of mounds per hectare was 68 in Pasture 1 and 127 in Pasture 2, representing 0.4 and 1 % of the entire area, respectively. A large majority of the mounds were active (vitality), 91 % in Pasture 1 and 84 % in Pasture 2. A "pure nugget effect" was observed in the semivariograms of height and nest circumference in both pastures reflecting randomized spatial distribution and confirming that the distribution of termite mounds in pastures had a non-standard distribution.

The neglected contribution of mound-building termites on CH4 emissions in Brazilian pastures

“…To calculate the area occupied by termite mounds, seven studies were used, all carried out in Brazilian Cerrado (Figure 1). Moreover, it was assumed that 88% of termite mounds are active, according to Lima et al (2015), Senci and Junqueira et al (2013), Lima et al (2011), and Cunha and Morais (2010).…”

“…Boddey et al (2004) suggested that at least 50% of Brazilian pastures were in advanced degradation stages, with low grass yield and soil cover, invaded by weeds, and in many cases densely occupied by termite mounds. In addition, in degraded Cerrado pastures, the mound-building termite population is usually high (Lima et al, 2015). According to Cunha and Morais (2010), the density increment of termite mounds in pastures could occur due to the homogeneity of the environment and less competitors/predators.…”

“…However, Cunha (2011) concluded that the mean basal area of termite mound was 1.05 m 2 . More recently, Lima et al (2015) published a value of 0.71 m 2 for basal area of the termite mounds in degraded pastures. Factors that influence variations in the basal area of termite mounds in pastures are not well established.…”

Termite mound density and distribution patterns across three land‐use types in the Vhembe District of the Limpopo Province, South Africa

“…A total of 40 mounds of the two most consumed species ( Macrotermes falciger and Macrotermes natalensis ) in the Vhembe District (Netshifhefhe et al., 2018) were randomly selected from all land‐use types and their dimensions (height, basal circumference and estimation of diameter) were measured using a measuring stick and measuring tape (Collins, 1981; Debelo & Degaga, 2014; Lima et al., 2015; Sands, 1961). The widest diameter and circumference were measured at ground level (where change in soil colour was visible or where changes in slope were noticeable), and the height measured using folded 2‐metre ruler (Kelly & Samways, 2011).…”

Spatial distribution patterns of the populations of two subterranean termites (Blattodea: Termitidae) in eucalyptus (Myrtales: Myrtaceae) plantations

“…Spatial distribution patterns of foraging populations of termites have been studied using various methods such as the nearest-neighbour technique for distance index (Korb and Linsenmair 2001), geostatistical techniques, Ripley's K function and pair correlation function for epigeal mound and subterranean population distributions (Crist 1998, Grohmann et al 2010, Lima et al 2015. Arifin et al (2014) reported in South Sumatra Palembang, Indonesia, the randomly distribution of epigeal mounds built by Macrotermes spp.…”