Data/hora: 11/06/2024 09:07:20

Biblioteca(s): | Embrapa Florestas.
Data corrente: | 18/09/2008
Data da última atualização: | 18/09/2008
Autoria: | BIGNELL, D.; NOBRE, T.; BERGE, L.; NUNES, L.; RAHMAN, H.
Título: | Line intersection (LIS) methods for the assessment of wood-feeding termites in natural, semi-natural and plantation forests.
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:

We review the development of line intersection (transect) methods for the estimation of lying
dead wood biovolume in forests, and show how the technique can be extended to assess the
overall impact of termites on the decomposition of woody materials. The protocol allows the
attacks on individual woody items attributable to termites and fungi to be distinguished and
scored semi-quantitatively, and may be useful in allocating contributions to decomposition where
the two groups compete for resources, or where termites have low diversity or show seasonal
activity, such as at higher latitudes. Line intersection is quantitative to the extent that it can link
foraging and decay parameters to woody biovolume. The method is also quick (about 50 personhours
of work are required to characterise one site with acceptable replication) and may therefore
be helpful in rapid biodiversity assessments (RBAs). A further advantage is that wood is not
removed from site for analysis; however as wood density is not recorded, the data cannot be
directly used to construct C budgets.
We report a first study (2002) in an equatorial primary rainforest (Sepilok, Sabah, Malaysia)
with a diverse termite assemblage (21 species of which about half were wood-feeders). A sample
of more than 2000 items of woody litter in 9 replicated plots of 30 x 30 m showed that while small
items (< 50 mm diameter) were most common (ranging 50-70% of all items encountered), the
greater part of the combined biovolume of all lying dead wood was made up by large items
(>100 mm diameter) and notably by very large items (>200 mm diameter), although these were
fewer in number and in density (number per unit area). Most items of litter (at least 50%) showed
significant decay by fungi, while those with evidence of severe attack were relatively fewer, but
nevertheless represented the greatest part of the lying biovolume. This suggested that termite
attack and the corresponding contribution to decomposition was focussed on larger items,
although live occupancy was no more than 10% of available items in most plots.
In a subsequent study, subterranean wood-feeding termites (Reticulitermes grassei) were
surveyed in a managed eucalyptus plantation in south eastern Portugal for 26 months (2002-
2004), over successive seasons. In 3 replicated plots of 30 x 30 m, each woody item sampled
was allocated to one of seven diameter categories, then assessed for termite attack and for
general (i.e. fungal) decay status using standard protocols. While the great majority of items
sampled were of small diameter (<15 mm), it was found that termites selected items with larger
diameter, the trend observed showing an exponential character with greater termite attack as
diameter increased. Further, attack by termites was positively associated with prior decay by
fungi. A clear positive relationship was shown between rainfall and total woody biovolume
containing live termites, underlining the importance of moisture for termite activity, and perhaps
explaining why larger items are preferred. An average of 30% of lying dead wood branches
showed signs of termite attack.

Categoria do assunto: | --
Registro original: | Embrapa Florestas (CNPF)
Exemplares: | CNPF - (43633-1) - UPE - PL - -- - CD0305 -  -  - DIS