Data/hora: 18/06/2024 18:22:31

Biblioteca(s): 	Embrapa Florestas.	
Data corrente: 	15/09/2008	
Data da última atualização: 	15/09/2008	
Autoria: 	ANICHKIN, A.; TIUNOV, A.	
Título: 	Soil macrofauna in a monsoon tropical forest (South Vietnam): taxonomic structure, seasonal dynamics and impact on litter decomposition.	
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: 	Deciduous and semi-deciduous tropical monsoon forests occupy large areas in both
hemispheres. We investigated soil macrofauna in lowland Lagerstroemia-dominated forests of
the Nam Cat Tien National Park (11°N, 107°E). The study was conducted during two years (five
sampling sessions per year) at five model plots differing in canopy structure, tree species
composition and edaphic conditions. Ca. 800 standardized soil samples (25 õ 25 cm, 30 cm
deep) were taken and hand-sorted.
The diversity and abundance of soil invertebrates was high and comparable with those in wet
tropical forests of the region. On average, each soil sample (0.0625 m2) contained 21
morphospecies and 2.6 g l.w. of soil invertebrates (ants and termites are not included here and
below).
The density of soil macrofauna reached maximum (1300 - 1800 N/m2 , up to 67 g l.w. /m2)
during the wet season, from June to August. Subsequently, the density and biomass decreased
till lowest values in September - October (400 N/m2 and 13 g l.w./m2). During the dry season
(December ? April) the density of soil animals increased (500 - 900 N/m2) though the biomass
decreased (from 10 to 7 g l.w. /m2).
This trend was caused by the increase in dominance of small-sized animals and early larval
stages of arthropods. However, there was also a strong change in the taxonomic and functional
structure of soil community.
Two fairly distinct taxonomic assemblages, ?xerophilic? and ?mesophilic?, associated respectively
with dry and wet season, could be recognized. In the dry season, active stages of soil invertebrates
were represented mainly by larvae and imagoes Tenebrionidae, Psocoptera, Thysanoptera,
larvae Blattidae. These saprotrophs supported a large number of juvenile predators like Aranea
(Zodariidae, Linyphiidae, Oonopidae). In the wet season Isopoda, Diplopoda, Geophilidae,
Lithobiidae, larvae Diptera and earthworms predominated in abundance and biomass. The
abundance of termites (Macrotermes, Microtermes, Termes, Odontotermes, Globitermes) did
not fluctuate significantly during the year (ca. 5 g l.w. /m2) but their activity in the dry season was
strongly limited by low air and soil moisture.
The observed dynamics of soil animal communities is likely driven by the interplay of two main
factors: the moisture availability and the amount of leaf litter on soil surface. The main litterfall
(ca. 300 g d.w. /m2 per month) occurs in January, when deciduous trees from upper canopy
shed leaves. Low moisture prevents litter decomposition by microbial and animal saprotrophs.
At the beginning of the wet season the accumulated litter (500-700 g/m2) starts to decompose
by the quickly developing ?mesophilic? community of soil invertebrates. The litter decomposition
is almost completed in two months. However, some leaf litter (ca. 50 g /m2 in September) presents
constantly on the soil surface due to permanent litterfall from evergreen understory trees.
As shown by litterbag experiments, soil microorganisms and mesofauna contribute little in the
decomposition process. Litter in fine-mesh (0.4 mm) litterbags retained 60-70% of initial weight
after 12 months of decomposition	
Categoria do assunto: 	--	
Registro original: 	Embrapa Florestas (CNPF)	
Exemplares: 	CNPF - (43567-1) - UPE - PL - -- - CD0305 -  -  - DIS