Leaf‐cutting ants, seasonal burning and nutrient distribution in Cerrado vegetation

Abstract

Fire and herbivory are known to modify plant community structure. Many studies have suggested that fire ashes may increase soil nutrients in dystrophic soils. Herbivores may also change plant community structure through direct effects of herbivory and affecting nutrient cycling. Leaf-cutting ants were traditionally viewed as herbivores, although their role may be more complex, because their nests affect both chemical and physical soil properties, thus affecting plants indirectly. We investigated the effects of frequent burning and of leaf-cutting ants on the nutrient status of an herbaceous and a shrub species occurring in the Brazilian Cerrado, a habitat that is characterized by natural burnings. The proximity of ant nests resulted in an increase of nutrients in the leaves of both vegetation strata, whereas burning sometimes resulted in a decrease of nutrients. Our results do not lead to a possible positive effect of fire on plant nutrient content. On the other hand, ant nests may represent an important source of nutrients for plants on the nutrient-depleted Cerrado soils and may accelerate vegetation recovery after burning.

Ant Assemblage Structure in a Secondary Tropical Dry Forest: The Role of Ecological Succession and Seasonality

“…In the intermediate and late stages, there is a higher diversity of plants, and the soil is more porous. The hypogaeic stratum presents change in the ant fauna (Schmidt & Solar, 2010) that are closely linked to processes occurring in the vegetation, which could also contribute to the movement of water and soil as well as nutrient cycling (Sousa-Souto et al, 2007). Thus, the changes in soil following disturbance exert pressure on the ant assemblage in this stratum, which results in a decrease in diversity.…”

Check list of ground-dwelling ants (Hymenoptera: Formicidae) of the eastern Acre, Amazon, Brazil

“…However, the distribution of terrestrial invertebrates is relatively unknown (Morato et al 2005). For example, to our knowledge, only one ant survey carried out in Acre state was published until now (Oliveira et al 2009), although these insects are frequently mentioned as key-organisms to the functioning of tropical forests by changing the physical and chemical soil structure (Folgarait 1998;Moutinho et al 2003, Sousa-Souto et al 2007, seed dispersion (Handel andBeattie, 1990, Levey andByrne, 1993) and control of herbivorous insect population (Dyer and Letourneau 1999).…”

Soil Attributes on Planting Mode in Corn Intercropping With Forage

“…Essa necessidade foi constatada por Chowdhury et al, (2007) que estudaram o comportamento de alguns atributos do solo em pomar de laranjas em uma região de Bangladesh e verificaram que com a modalidade de semeadura intensivo do solo feito pelos agricultores houve aumento da densidade do solo, redução da fauna do solo e diminuição do teor de matéria orgânica. Com a construção de galerias no solo, alteram as suas propriedades físicas, e por meio de suas ações mecânicas no solo contribuem para a formação de agregados estáveis e proteção da matéria orgânica contra mineralização rápida (SOUSA-SOUTO et al, 2007;SOUSA-SOUTO et al, 2008). Segundo a manutenção e melhoria das condições físicas internas e externas do solo, a adição e o balanço da matéria orgânica são fundamentais, pois essa manutenção e melhoria só poderão ser alcançadas e mantidas por via biológica, isto é, por meio da ação de raízes, da atividade macro e microbiana e da decomposição da matéria orgânica.…”