Data/hora: 06/06/2024 13:49:27

Biblioteca(s): | Embrapa Florestas.
Data corrente: | 23/09/2008
Data da última atualização: | 23/09/2008
Autoria: | CARES, J. E.; ANDRADE, E. P.
Título: | The potential of soil nematodes as a tool for monitoring sustainability in Amazonian land use systems.
Ano de publicação: | 2008
Fonte/Imprenta: | In: INTERNATIONAL COLLOQUIUM ON SOIL ZOOLOGY, 15; INTERNATIONAL COLLOQUIUM ON APTERYGOTA, 12., 2008, Curitiba. Biodiversity, conservation and sustainabele management of soil animal: abstracts. Colombo: Embrapa Florestas. Editors: George Gardner Brown; Klaus Dieter Sautter; Renato Marques; Amarildo Pasini. 1 CD-ROM.
Idioma: | Inglês

Conteúdo:

Nematodes are small invertebrate animals, known as the most abundant metazoan on earth.
Soil nematode community includes five major trophic groups: plant parasites (PP), bacteriovores
(BF), fungivores (FF), predators (PR) and omnivores (OM). Regardless functional group, all of
them contribute to nutrient cycling and are part of soil food web. The nematodes range from
agricultural pests, as the plant parasites, through beneficial organisms, as the entomopathogenic
that contribute to control agricultural pests. Due to their short life span and different feeding
functions, nematodes reflect environmental changes in their community structure and composition.
Colonizer nematodes, are tolerant to soil disturbance, and their populations increase in conditions
of nutrient enrichment, while persister nematodes prefer stabilized environment with structured
food chain. With aid of ecological measurement tools, nematodes have been used as indicators
of a variety of natural and anthropic environment alterations, as the impact of agricultural
practices, soil contamination with chemical pollutants, and to monitor recovery of degraded
lands. With the objective of evaluating the potential of nematode communities as a tool for
monitoring sustainability of Amazonian land use systems, a survey of soil nematodes was carried
out, as one of the activities of the project Conservation and sustainable management of below
ground biodiversity in Benjamin Constant, upper Solimões river, Amazonas, Brazil. In March
2004, 96 composite soil samples had been collected in six windows, of three different locations:
windows 1-2, in Guanabara II; 3-5, in Nova Aliança; 6, nearby the town of Benjamin Constant.
The sampling comprised six major land use systems (lus): 16 samples from Primary forest (Pf);
06 from Secondary forest (Sf), over ten years; 34 from Short term secondary forest (Ssf), under
10 years; 09 from Agroforestry system (Agf), with a variety of fruit trees; 19 from Crops (Cr),
mainly cassava and bananas; 13 form Pasture (Pa). Spatially, the sampling points were distributed
in a grid with quadrants of 100 x 100 m. Soil samples were collected in the top layer (0-20 cm).
Nematodes had been extracted from 300cc of soil, by sieving and sugar floatation procedures,
formalin fixed, counted, and glycerin infiltrate. Permanent slide mounts were prepared with 100
nematodes randomly picked for generic identification. Eighty-two genera in 36 families were
identified. Regardless lus, the communities were dominated by plant parasites. Nematode
diversity and trophic diversity were higher in Primary and in Secondary forest, and lower in
Pasture, while total abundance was higher in Pasture and Secondary forest. Relative abundance
for each trophic group decreased as follows: PP% (Agf >Ssf>Pa>Pf >Cr>Sf ); FF% (Sf >Pf
>Agf >Cr >Ssf >Pa); BF% (Sf >Cr>Pf > Ssf >Agf >Pa); PR% (Pf>Cr >Sf >Agf >Ssf>Pa); OM%
(Sf>Pa>Pf>Cr>Ssf>Agf). The ratio FF/BF indicates that decomposition was dominated by fungi,
in all lus. For all systems, Maturity and Plant parasite indices were below 2.5, a characteristic of
disturbed systems. The analyses mostly indicated pasture apart from the other lus, and the
Secondary forest and remaining systems (Ssf, Agf, and Cr) tending to the conditions of the
Primary forest. Funded by GEF-UNEP; implemented by TSBF-CIAT.

Categoria do assunto: | --
Registro original: | Embrapa Florestas (CNPF)
Exemplares: | CNPF - (43683-1) - UPE - PL - -- - CD0305 -  -  - DIS