umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A long-term phytometer study to evaluate stream restoration along climate and discharge gradients
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. (Landskapsekologi)
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. (Landskapsekologi)
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. (Landskapsekologi)
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Simplified channel morphology caused by the channelization of rivers to facilitatetimber floating resulted in a less variable flow regime with faster flows in the mainchannel. Restoration measures aiming to counteract these impacts, such as the returnof boulders to the channel and the reconnection of the riparian zone with instreamhabitats, are expected to create a higher, more natural hydrological variability andenhance riparian site quality. In this study, we analysed the number and duration offlooding events at channelized and restored river reaches with an indirect methodusing diurnal temperature oscillation. In a long-term field experiment, we evaluatedthe effect of flooding regime on riparian plant performance by measuring survival andbiomass increment of two transplanted phytometer species, a grass (Molinia caerulea)and a forb (Filipendula ulmaria). We found that flow variability was significantlyhigher at restored compared to channelized sites in medium-sized and large streams,particularly during summer months. Phytometer performance was better at restoredsites and positively correlated with summer flooding, indicating that a more variableflow after restoration improved site conditions for phytometer growth. This may notonly result from the higher heterogeneity in channel morphology caused by thereturned boulders, but can probably also be attributed to a lower flow velocity atrestored sites. Flood variables were more often correlated with other abiotic variablesat restored than at channelized sites, which points to an increased land-waterconnectivity as a result of restoration.

Keyword [en]
bioassay; channelization; environmental disturbance; Filipendula ulmaria;
National Category
Ecology
Research subject
Ecological Botany
Identifiers
URN: urn:nbn:se:umu:diva-67643OAI: oai:DiVA.org:umu-67643DiVA: diva2:619500
Funder
Formas, 215-2006-491
Available from: 2013-05-03 Created: 2013-03-25 Last updated: 2013-05-06Bibliographically approved
In thesis
1. Use of phytometers for evaluating ecological restoration
Open this publication in new window or tab >>Use of phytometers for evaluating ecological restoration
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The increase in ecological restoration can be attributed to valuation of healthyecosystems and concerns for future climate changes. Freshwaters belong among theglobally most altered ecosystems and are restored to counteract human impacts.Many Swedish streams that were channelized to facilitate timber floating have beenrestored by returning boulders and reconnecting riparian with instream habitats.Evaluation of restoration lacks reliable indicators of organism performance, possiblydue to the complexity of ecosystem responses. Phytometers, i.e. standardized plantstransplanted to different environments, are important indicators of restorationsuccess. Phytometers integrate multiple environmental factors and measureecosystem functions directly. This thesis combines a literature review with threeexperiments and focuses on phytometer use for evaluating ecological restoration. Werecommend using different phytometer species, life-forms and life-stages and longexperiments (>1 year) to obtain high resolution and generality (I). In greenhouse andfield experiments we investigated the effect of restoring channelized rivers onphytometers and abiotic variables in the riparian zone. We hypothesized thatphytometer performance varies with stream size and climate. In the greenhouse, weanalysed differences in fertility between channelized and restored reaches by growingphytometers on soils from experimental sites (II). Phytometers grew better on soilsfrom restored sites in small streams, indicating a positive effect of restoration on soil.We detected this effect already 3-7 years after restoration, suggesting a fasterrecovery than predicted. In a short-term field experiment focusing on germinationand establishment of sunflowers, seedling survival, substrate availability, and soilnutrient content in large streams were enhanced by restoration (III). Overall,phytometers performed best at high altitudes and short growing seasons. The use ofMolinia caerulea and Filipendula ulmaria as phytometers in a long-term fieldexperiment (IV) revealed a better performance at restored sites. One reason was thatsummer flow-variability was higher, particularly in medium-sized streams. Sincephytometers allocated more biomass to belowground parts at restored compared tochannelized sites, it seems important to separate above- and belowground biomass inrestoration evaluation. Restoration outcomes vary with location in the catchment.Knowing such potentially different responses could guide restorationists in where tolocate restoration to be effective or successful. We suggest that small streams reactparticularly fast to restoration. Given that the proportion of small streams is high andthat restoration success in headwaters may favour downstream reaches, werecommend restoration to begin in tributaries to larger rivers. It is not always knownwhy phytometers react the way they do. Greenhouse experiments can disentangle thecauses of phytometer responses in the field by focusing on single environmentalfactors. We demonstrate that phytometers integrate ecosystem responses torestoration by reflecting how environmental factors affect plants under fieldconditions. Further studies are needed to better understand the underlyingmechanisms.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2013. 31 p.
Keyword
Bioassay, Channelization, Ecosystem change, Ecosystem response
National Category
Ecology
Research subject
Ecological Botany
Identifiers
urn:nbn:se:umu:diva-70098 (URN)978-91-7459-623-6 (ISBN)
Public defence
2013-05-31, Uminova Science Park, Tvistevägen 48, Älgsalen, Umeå universitet, Umeå, 10:00 (English)
Opponent
Supervisors
Funder
Swedish Research Council Formas, 215-2006-491
Available from: 2013-05-08 Created: 2013-05-03 Last updated: 2015-07-07Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Dietrich, AnnaNilsson, ChristerJansson, Roland
By organisation
Department of Ecology and Environmental Sciences
Ecology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 628 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf