Mellan torka och översvämning på Öland

Kaj Sand-Jensen; Lars Båstrup-Spohr; Jesper Philip Aagaard Christensen; Anette Baisner Alnøe; Mikkel René Andersen; Thomas Sand Jespersen; Tenna Riis; Hans Henrik Bruun

Mellan torka och översvämning på Öland

Kaj Sand-Jensen, Lars Båstrup-Spohr, Jesper Philip Aagaard Christensen, Anette Baisner Alnøe, Mikkel René Andersen, Thomas Sand Jespersen, Tenna Riis, Hans Henrik Bruun

2 Citations (Scopus)

Abstract

The Great Alvar plain on the Swedish island of Öland is characterized by thin soils covering the hard limestone pavements. This results in widely fluctuating water levels between winter flooding and summer draught and strong hydrological gradients along small changes in elevation. The semi-natural grassland, the intermittent streams and the ponds are all strongly influenced by the fluctuating water levels and the extremely low phosphorus availability. These factors have selected for phototrophs with low metabolic rates and growth, and communities with low levels of photosynthesis and respiration. We here present some of the results of our recent studies. Plant species were distinctively distributed according to their characteristic plant traits along water gradients from ponds to dry alvar. High root porosity to ensure efficient oxygen transport was strongly selected for among species in wet soils, while small, thick leaves were strongly selected for on thin, dry soils. Overall, six plant traits could predict 66% of the variation in abundance of plant species in the communities along the gradient. The alvar streams had only modest biomasses during maximum development of benthic algae in May, and community photosynthesis was 5-10 times lower than corresponding levels in nutrient-rich streams in cultivated lowlands of Scandinavia. During June-September streams dried out and the re-establishment of flow in winter and spring led to an export of nutrients. Shallow ponds also dried out during summer and had low metabolic rates just like streams, while permanent ponds developed dense stands of charophytes, despite undetectable levels of N and P. Photosynthesis and community respiration were in approximate balance in permanent ponds. The maximum rates were comparable to those in eutrophic, phytoplankton-rich lakes.

Original language	Swedish
Journal	Svensk Botanisk Tidskrift
Volume	109
Issue number	1
Pages (from-to)	28–35
Number of pages	8
ISSN	0039-646X
Publication status	Published - 2015

Keywords

Faculty of Science

Cite this

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title = "Mellan torka och {\"o}versv{\"a}mning p{\aa} {\"O}land",

abstract = "The Great Alvar plain on the Swedish island of {\"O}land is characterized by thin soils covering the hard limestone pavements. This results in widely fluctuating water levels between winter flooding and summer draught and strong hydrological gradients along small changes in elevation. The semi-natural grassland, the intermittent streams and the ponds are all strongly influenced by the fluctuating water levels and the extremely low phosphorus availability. These factors have selected for phototrophs with low metabolic rates and growth, and communities with low levels of photosynthesis and respiration. We here present some of the results of our recent studies. Plant species were distinctively distributed according to their characteristic plant traits along water gradients from ponds to dry alvar. High root porosity to ensure efficient oxygen transport was strongly selected for among species in wet soils, while small, thick leaves were strongly selected for on thin, dry soils. Overall, six plant traits could predict 66% of the variation in abundance of plant species in the communities along the gradient. The alvar streams had only modest biomasses during maximum development of benthic algae in May, and community photosynthesis was 5-10 times lower than corresponding levels in nutrient-rich streams in cultivated lowlands of Scandinavia. During June-September streams dried out and the re-establishment of flow in winter and spring led to an export of nutrients. Shallow ponds also dried out during summer and had low metabolic rates just like streams, while permanent ponds developed dense stands of charophytes, despite undetectable levels of N and P. Photosynthesis and community respiration were in approximate balance in permanent ponds. The maximum rates were comparable to those in eutrophic, phytoplankton-rich lakes.",

keywords = "Det Natur- og Biovidenskabelige Fakultet, Community ecology, physiological ecology, Limnology",

author = "Kaj Sand-Jensen and Lars B{\aa}strup-Spohr and Christensen, {Jesper Philip Aagaard} and Aln{\o}e, {Anette Baisner} and Andersen, {Mikkel Ren{\'e}} and Jespersen, {Thomas Sand} and Tenna Riis and Bruun, {Hans Henrik}",

year = "2015",

language = "Svensk",

volume = "109",

pages = "28–35",

journal = "Svensk Botanisk Tidskrift",

issn = "0039-646X",

publisher = "Svenska Botaniska Foereningen",

number = "1",

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TY - JOUR

T1 - Mellan torka och översvämning på Öland

AU - Sand-Jensen, Kaj

AU - Båstrup-Spohr, Lars

AU - Christensen, Jesper Philip Aagaard

AU - Alnøe, Anette Baisner

AU - Andersen, Mikkel René

AU - Jespersen, Thomas Sand

AU - Riis, Tenna

AU - Bruun, Hans Henrik

PY - 2015

Y1 - 2015

N2 - The Great Alvar plain on the Swedish island of Öland is characterized by thin soils covering the hard limestone pavements. This results in widely fluctuating water levels between winter flooding and summer draught and strong hydrological gradients along small changes in elevation. The semi-natural grassland, the intermittent streams and the ponds are all strongly influenced by the fluctuating water levels and the extremely low phosphorus availability. These factors have selected for phototrophs with low metabolic rates and growth, and communities with low levels of photosynthesis and respiration. We here present some of the results of our recent studies. Plant species were distinctively distributed according to their characteristic plant traits along water gradients from ponds to dry alvar. High root porosity to ensure efficient oxygen transport was strongly selected for among species in wet soils, while small, thick leaves were strongly selected for on thin, dry soils. Overall, six plant traits could predict 66% of the variation in abundance of plant species in the communities along the gradient. The alvar streams had only modest biomasses during maximum development of benthic algae in May, and community photosynthesis was 5-10 times lower than corresponding levels in nutrient-rich streams in cultivated lowlands of Scandinavia. During June-September streams dried out and the re-establishment of flow in winter and spring led to an export of nutrients. Shallow ponds also dried out during summer and had low metabolic rates just like streams, while permanent ponds developed dense stands of charophytes, despite undetectable levels of N and P. Photosynthesis and community respiration were in approximate balance in permanent ponds. The maximum rates were comparable to those in eutrophic, phytoplankton-rich lakes.

AB - The Great Alvar plain on the Swedish island of Öland is characterized by thin soils covering the hard limestone pavements. This results in widely fluctuating water levels between winter flooding and summer draught and strong hydrological gradients along small changes in elevation. The semi-natural grassland, the intermittent streams and the ponds are all strongly influenced by the fluctuating water levels and the extremely low phosphorus availability. These factors have selected for phototrophs with low metabolic rates and growth, and communities with low levels of photosynthesis and respiration. We here present some of the results of our recent studies. Plant species were distinctively distributed according to their characteristic plant traits along water gradients from ponds to dry alvar. High root porosity to ensure efficient oxygen transport was strongly selected for among species in wet soils, while small, thick leaves were strongly selected for on thin, dry soils. Overall, six plant traits could predict 66% of the variation in abundance of plant species in the communities along the gradient. The alvar streams had only modest biomasses during maximum development of benthic algae in May, and community photosynthesis was 5-10 times lower than corresponding levels in nutrient-rich streams in cultivated lowlands of Scandinavia. During June-September streams dried out and the re-establishment of flow in winter and spring led to an export of nutrients. Shallow ponds also dried out during summer and had low metabolic rates just like streams, while permanent ponds developed dense stands of charophytes, despite undetectable levels of N and P. Photosynthesis and community respiration were in approximate balance in permanent ponds. The maximum rates were comparable to those in eutrophic, phytoplankton-rich lakes.

KW - Det Natur- og Biovidenskabelige Fakultet

KW - Community ecology

KW - physiological ecology

KW - Limnology

M3 - Tidsskriftartikel

SN - 0039-646X

VL - 109

SP - 28

EP - 35

JO - Svensk Botanisk Tidskrift

JF - Svensk Botanisk Tidskrift

IS - 1

ER -