Data/hora: 12/06/2024 07:24:30

Biblioteca(s): | Embrapa Florestas.
Data corrente: | 03/10/2008
Data da última atualização: | 03/10/2008
Autoria: | PENNINGS, A.; VALCKX, J.; GOVERS, G.; HERMY, M.; MUYS, B.
Título: | Dispersal of the earthworm Lumbricus terrestris L. in an experimental setup.
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:

Intensive soil management in modern agro-ecosystems (e.g. ploughing) has led to severe
reductions of earthworm communities, and sometimes to local extinction of certain species.
Nowadays farmers increasingly switch to more sustainable production systems such as
conservation agriculture. The latter tend to be more earthworm-friendly as they result in less soil
disturbance and more food at the soil surface leading to more suitable living conditions for
earthworms. It is, however, not known to what extent recolonization of earthworms from nearby
remnant populations (e.g. in grass strips) could contribute to a successful recovery of depleted
populations. Also, within agricultural parcels, dispersal may play an important role in both
population dynamics and interspecies interactions. As a consequence, dispersal may influence
thoroughly the diversity, structure and functions of earthworm communities in agro-ecosystems.
But knowledge about the factors that govern horizontal surface dispersal and quantitative direct
observations of dispersal speed and distances are scarce.
This study investigated the influence of habitat quality and interactions with congeners on the
surface activities and dispersal speed and distance of the anecic earthworm L. terrestris L. in
laboratory conditions.
The nightly behaviour of the animals was studied by means of IR-sensitive webcams in longitudinal
experimental units of adjustable length in which individuals could freely move over the soil surface.
Prior to the experiment, specimen were housed in PVC tubes for acclimatization. During the
experiments, these tubes were connected to the experimental units. A Matlab® procedure was
used to extract coordinates of the position of the earthworms in time based on the pixel information
in the photographs. From this information migration characteristics such as speed, crawl distance
and pattern were obtained. Manipulations consisted of waterlogging, pesticide application and
mechanical vibration of the PVC tubes.
Preliminary results confirmed that L. terrestris is a territorial species that under normal conditions
does not leave its burrow on which it depends for survival and reproduction. However, in adverse
circumstances (waterlogging, pesticide percolation, vibrations) individuals were capable of
travelling significant distances over the soil surface of more than 2 metres per 12 h night period,
at a maximum speed of 0.1 m per minute. Manipulations did not always result in dispersal,
although dispersal was significantly higher in manipulated than in control PVC tubes. Individuals
in non-manipulated tubes never dispersed. These observations indicate that habitat quality may
play a role in surface dispersal, but it is not totally determinative.
In can be concluded that, although L. terrestris behaves territorial by nature, it transforms in a
potential long-distance disperser when conditions require. Dispersal behaviour of this and other
species requires further investigation, preferably based on the study of field populations.

Categoria do assunto: | --
Registro original: | Embrapa Florestas (CNPF)
Exemplares: | CNPF - (43792-1) - UPE - PL - -- - CD0305 -  -  - DIS