Terrestrial invertebrates working group

Responsible:

  • Ana Lúcia Tourinho

Participants:

  • Suzana Ketelhut
  • Thiago Izzo
  • Jessica Viana
  • Willians Porto
  • Lina Almeida
  • Ivan Meireles
  • Gustavo Miranda
  • Pío Colmenares
  • Sérvio Olusogba Pontes Ribeiro
  • Renata Campos

Study proposal

Considering the wide diversity and abundance of terrestrial invertebrates, the existence of several endemic species, the high sensitivity of these animals to environmental changes, the low cost to perform the collections, as well as the relatively high speed to obtain relevant results for environmental monitoring; the group proposes to do the monitoring of the Rio Doce/Minas Gerais State area. This region was severely affected by the rupture of two dams from the mining plants of the Samarco company.

General Objectives:

  1. Evaluate the impact of tailings and the contamination of Rio Doce’s terrestrial invertebrate fauna in the surroundings of the river’s main channel;
  2. Quantify the loss of diversity in focus groups distributed in the region;
  3. Determine which species, if any, are susceptible to contamination and evaluate risks and consequences in case of contamination;
  4. Monitor the effects of tailings on the terrestrial invertebrates fauna in the medium and long terms.

 

Methods:

  1. Pitfall: the pitfall traps (plastic cups of 500 mL) are used to estimate the abundance and species composition of invertebrates with activity on the surface of the soil. The edge of the trap is covered with a thin layer of soil or leaf litter, and placed a few millimeters below the surface. In each plot, 10 traps are placed five meters apart from each other. Inside each trap, an alcohol solution (100%) is used to preserve the material, remaining in operation for 48 hours.
  2. Active night cryptic search: it is held over 250m plots for 1 hour, within a range of 2m wide. The focus of the collector is cryptic environments, such as fallen logs behind the bark off the trees, litter (including the suspended ones), in soil cavities and roots.
  3. Eclectors – type of “emergency” trap to capture arthropods that are located on the ground, but they can also capture the inhabitants from other sites, such as from the trunk and canopy areas dwelling around the ground or wetlands. Permanent catches using this method can assist in the inventory of species, studies of dominance, density, and phenology of arthropods (Adis, 2002). They consist of circular capture devices, with a basal area of 1m2 and covered by black fabric, a transparent collector bottle, and a trapdoor type trap without bait (pitfall). The side-walls (0.5m height) are made with grey PVC, and the fabric lid of the eclector is funnel-shaped, on which the top the plastic collector bottle is fastened. This fabric funnel is supported by four metal bars. The collector bottle is transparent and works as a “light trap”. The arthropods attracted by the light go up and/or fly through the walls of the trap and are captured by the collector bottle. To prevent their escape, the trap is partially buried in the soil. The trap-type pitfall, installed inside the eclector on the ground serves to decrease predation of animals that hatch by predators that are within the eclector. Once the site to deploy the trap is determined, the ground is disturbed as little as possible after its set up. Four photo-eclectors will be installed in 100m of cross-section in each sampling point. They will remain in place for 5 days in every area visited, which is the time required to fulfill the remaining protocols.
  4. Clap Nets: Collections made with the clap net (or entomological umbrella) will be performed during the morning. It comprises of a PVC pipe frame that holds a 1m2 white fabric, upon which the arthropods fall when vegetation is hit with a wooden bat. Bushes and other vegetation will be sampled along transects established in each plot. First, shrubs that touch the line will be sampled, and then those who are up to 2m away from it. The arthropods that fall on the fabric will be collected and stored in a plastic jar containing 100% alcohol. Each sampling hour along the transects will be regarded as a sampling unit.

 

Study areas:

  • Parque Estadual do Rio Doce (Rio Doce State Park)
  • Reserva Natural Vale (Vale Natural Reserva)
  • Floresta Nacional dos Goytacazes (Goytacazes National Forest)
  • Additional areas to be further identified