Soil Physical Quality and Relationship to Changes in Termite Community in Northwestern Colombian Amazon

Abstract

Conversion from Amazon forest to low-management pasture or agriculture causes not only degradation of aboveground vegetation but also negative changes in soil properties and ecosystem services. This study aimed to evaluate the impact of physical soil degradation on termite community changes in three contrasting land uses (natural regeneration, rubber plantations, and silvopastoral systems). Soil physical quality was assessed through a set of physical variables, such as bulk density, porosity, soil macro-aggregation state, Visual Evaluation of Soil Structure (VESS) and penetration resistance, which were summarized in an overall synthetic indicator of physical quality. Besides, transects of 20 × 2 m were established in each land use; each transect was divided into four sections of 5 m to search and collect termites during 1 hour in each section; likewise, termites were collected from blocks of soil 25 × 25 × 10 cm (length, width, and depth, respectively) adapted from the Tropical Soil Biology and Fertility (TSBF) method. In total, 60 transects were evaluated, 20 in each land use. A total of 41 species were collected across the three land uses evaluated: natural regeneration presented 60% of the collected species (25 species), silvopastoral systems 53% (22 species), and rubber plantations 39% (16 species). Additionally, composition species from the silvopastoral, agroforestry systems, and natural regeneration were different, and a close association between these last land uses was observed. Soil physical characteristics showed significant variations between land uses. The rubber plantations presented lowest values of soil physical quality, while the natural regeneration showed high soil physical quality. These changes affected termite community and lead to changes in its composition with disproportionate loss of some species; however, there are some that can acclimate well to the decline in the soil physical quality.

A “Dirty” Footprint: Macroinvertebrate diversity in Amazonian Anthropic Soils

“…The ADEs developed a different pool of species compared with REF soils. The former soils tend to favor more animals that recycle organic matter and flourish with higher pH and soil Ca, like earthworms and millipedes, while the latter favor termites, which are particularly sensitive to deforestation and changes in soil moisture and physical conditions (Dambros et al, 2013; de Souza & Brown, 1994; Duran‐Bautista, Muñoz Chilatra, et al, 2020; Eggleton et al, 1996). Similar microenvironmental characteristics of soil matrix and overlying vegetation probably have, and continue to influence soil fauna community composition in other anthropic soils in various regions of the world, such as in West Africa, Europe, and Central America (Macphail et al, 2017; Solomon et al, 2016; Wiedner et al, 2014).…”

First record of Ereymatermes rotundiceps (Termitidae: Nasutitermitinae) as inquiline of Embiratermes neotenicus (Termitidae: Syntermitinae) in the Colombian Amazon

“…We provide new morphometric information on head height and head length to the mandible lateral base, which is not included in the original description of the species. The little information for the Colombian Amazon region indicates a high diversity of termites (Castro et al 2021;Duran-Bautista et al 2020). The presence of E. neotenicus and E. rotundiceps had already been reported in this region by Castro et al (2021), but no co-habitation between these two species had been observed.…”

“…Currently the genus includes 14 species (Constantino 2020) of which some seem to live in nests built by other species (Constantino 1992). E. neotenicus builds an epigeal mound, with a high proportion of organic matter (Mathews 1977) and is one of the most abundant termite species in the Colombian amazon (Duran-Bautista et al 2020).…”

Soil Quality Restoration during the Natural Succession of Abandoned Cattle Pastures in Deforested Landscapes in the Colombian Amazon

“…Agronomy 2021, 11, x FOR PEER REVIEW 3 of 24 their relation to physical-chemical attributes and soil aggregation during the natural restoration of degraded pastures has not been widely addressed [45,62,63]. This study aimed to assess: (i) individual responses of soil physical, chemical and biological variables along the natural succession of abandoned pastures in two contrasting landscapes in the Colombian Amazon region, and (ii) evaluate individual and synthetic indicators of soil quality along the natural succession and their capacity to discriminate different successional stages along a natural restoring chronosequence.…”

“…For example, the GISQ can discriminate well between mature forest and covers dominated by grasses (pastures and silvopastoral systems) [49] and between covers with different intensity of use [48], but it has not yet proven if it can also discriminate the soil quality among different successional stages. In the same way, how soil macrofauna communities are influenced by the soil quality of the Amazon region [48,61] and how sensitive they are to soil disturbances, and their relation to physical-chemical attributes and soil aggregation during the natural restoration of degraded pastures has not been widely addressed [45,62,63].…”