Data/hora: 05/06/2024 06:24:40

Biblioteca(s): 	Embrapa Florestas.	
Data corrente: 	18/09/2008	
Data da última atualização: 	18/09/2008	
Autoria: 	ZAITSEV, A. S.; BERG, M. P.; STRAALEN, N. M. van.	
Título: 	Landscape age explains spatial trends in oribatid mite diversity.	
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: 	Spatial variance of soil fauna diversity is barely studied. Driving forces of this heterogeneity
in space at the regional level are mostly unknown. The aim of our study was to assess the
importance of the site geologic age (duration of continuous landscape development) on the
oribatid mite diversity in forest soils. We hypothesised that geologic site age plays a leading
role in explaining oribatid species richness increase or decrease, while edaphic factors such
as humidity, nutrient status, soil type and forest type act as secondary modulating forces.
We also wanted to show that changes of local oribatid species richness are ensured by the
change in community composition and is strongly determined by the life history tactics of
species. We selected the Netherlands territory to test these hypotheses. With a few exceptions
the age of the landscapes here is increasing with the distance from the sea, starting from a
few decades for recently reclaimed polders to Early Pleistocene formations in the Southeastern
part of the country. It does not contain any obvious biogeographic or natural borders.
The study area was divided into five age classes. Do diminish the impact of edaphic and
anthropogenic factors we decided to focus the research on forests, as the least disturbed
ecosystems. In total 41 forest sites were selected, which were regularly distributed over the
Netherlands. They were sampled in 2000. In each location 5 samples were taken. Also soil
type, thickness of organic matter, actual and average humidity and nutrient status were
assessed. Mites were extracted using high gradient extractors, counted and identified to a
species level. A total of 145 species of Oribatida were found, which belonged to 85 genera
and 39 families. Observed species richness varied between sites from 11 to 49 species,
while the potential estimated total species richness per site ranged between 15 and 68
species from the Western coast to the eastern Pleistocene sands. The following ranking
towards an increase in oribatid species richness could be made: newly reclaimed polders <
river bottomlands ? Pleistocene sites on loess soils < ?natural? Holocene sites < coastal
sand dunes of northern part of Holland < Pleistocene part. Sandy soils tended to bear more
species but the general trend of oribatid diversity increase was observed for both sandy and
clayish soils. Soil moisture and nutrient status did not add any explained variance. With site
age the number of K-strategists significantly increased, especially from the Holocene sites
to the Pleistocene sites. Also the number of rare species increased with age. Multiple linear
regression analysis revealed that environmental factors, i.e. soil water availability and soil
nutrient status did not strongly effect diversity of oribatid mites. Soil type played a modulating
role. Site age explained the highest portion of variance among all factors considered. We
may conclude that landscape age plays an important role in explaining spatial distribution of
Oribatid diversity. Diversity increase is substantiated by mainly rare species and K-strategists.
The research was supported by the fellowship provided by VU and RFBR grant 06-05-
64902.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Florestas (CNPF)	
Exemplares: 	CNPF - (43631-1) - UPE - PL - -- - CD0305 -  -  - DIS