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Malm-Renöfält, Birgitta
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Publikasjoner (10 av 18) Visa alla publikasjoner
Kuglerová, L., Jansson, R., Sponseller, R., Laudon, H. & Malm-Renöfält, B. (2015). Local and regional processes determine plant species richness in a river-network metacommunity. Ecology, 96(2), 381-391
Åpne denne publikasjonen i ny fane eller vindu >>Local and regional processes determine plant species richness in a river-network metacommunity
Vise andre…
2015 (engelsk)Inngår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 96, nr 2, s. 381-391Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

River systems form dendritic ecological networks that influence the spatial structure of riverine communities. Few empirical studies have evaluated how regional, dispersal-related processes and local habitat factors interact to govern network patterns of species composition. We explore such interactions in a boreal watershed and show that riparian plant species richness increases strongly with drainage size, i.e., with downstream position in the network. Assemblage composition was nested, with new species successively added downstream. These spatial patterns in species composition were related to a combination of local and regional processes. Breadth in local habitat conditions increased downstream in the network, resulting in higher habitat heterogeneity and reduced niche overlap among species, which together with similar trends in disturbance, allows more species to coexist. Riparian edaphic conditions were also increasingly favorable to more species within the regional pool along larger streams, with greater nitrogen availability (manifested as lower C:N) and more rapid mineralization of C and N (as indicated by ratios of stable isotopes) observed with downstream position in the network. The number of species with capacity for water dispersal increased with stream size providing a mechanistic link between plant traits and the downstream accumulation of species as more propagules arrive from upstream sites. Similarity in species composition between sites was related to both geographical and environmental distance. Our results provide the first empirical evidence that position in the river network drives spatial patterns in riparian plant diversity and composition by the joint influence of local (disturbance, habitat conditions, and breadth) and regional (dispersal) forces.

Emneord
boreal, connectivity, dispersal, disturbance, hydrochory, riparian, river network, soil conditions, spatial organization, vascular plants
HSV kategori
Forskningsprogram
biologi, miljövetenskap; ekologisk botanik
Identifikatorer
urn:nbn:se:umu:diva-100211 (URN)10.1890/14-0552.1 (DOI)000350484600010 ()
Eksternt samarbeid:
Forskningsfinansiär
Swedish Research Council Formas
Tilgjengelig fra: 2015-02-25 Laget: 2015-02-25 Sist oppdatert: 2018-06-07bibliografisk kontrollert
Kuglerova, L., Jansson, R., Ågren, A., Laudon, H. & Malm-Renöfält, B. (2014). Groundwater discharge creates hotspots of riparian plant species richness in a boreal forest stream network. Ecology, 95(3), 715-725
Åpne denne publikasjonen i ny fane eller vindu >>Groundwater discharge creates hotspots of riparian plant species richness in a boreal forest stream network
Vise andre…
2014 (engelsk)Inngår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 95, nr 3, s. 715-725Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Riparian vegetation research has traditionally focused on channel-related processes because riparian areas are situated on the edge of aquatic ecosystems and are therefore greatly affected by the flow regime of streams and rivers. However, due to their low topographic position in the landscape, riparian areas receive significant inputs of water and nutrients from uplands. These inputs may be important for riparian vegetation, but their role for riparian plant diversity is poorly known. We studied the relationship between the influx of groundwater (GW) from upland areas and riparian plant diversity and composition along a stream size gradient, ranging from small basins lacking permanent streams to a seventh-order river in northern Sweden. We selected riparian sites with and without GW discharge using a hydrological model describing GW flow accumulation to test the hypothesis that riparian sites with GW discharge harbor plant communities with higher species richness. We further investigated several environmental factors to detect habitat differences between sites differing in GW discharge conditions. Vascular plant species richness was between 15% and 20% higher, depending on the spatial scale sampled, at riparian sites with GW discharge in comparison to non-discharge sites, a pattern that was consistent across all stream sizes. The elevated species richness was best explained by higher soil pH and higher nitrogen availability (manifested as lower soil C/N ratio), conditions which were positively correlated with GW discharge. Base cations and possibly nitrogen transported by groundwater may therefore act as a terrestrial subsidy of riparian vegetation. The stable isotopes N-15 and C-13 were depleted in soils from GW discharge compared to non-discharge sites, suggesting that GW inputs might also affect nitrogen and carbon dynamics in riparian soils. Despite the fact that many flows of water and nutrients reaching streams are filtered through riparian zones, the importance of these flows for riparian vegetation has not been appreciated. Our results demonstrated strong relationships between GW discharge, plant species richness and environmental conditions across the entire stream size gradient, suggesting that both river hydrology and upland inputs should be considered to fully understand riparian vegetation dynamics.

sted, utgiver, år, opplag, sider
Ecological Society of America, 2014
Emneord
boreal forest, groundwater discharge, Krycklan catchment, riparian zone, soil nitrogen, soil pH, species richness, terrestrial subsidy, vascular plants
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-88681 (URN)10.1890/13-0363.1 (DOI)000332823100019 ()
Tilgjengelig fra: 2014-05-16 Laget: 2014-05-12 Sist oppdatert: 2018-06-07bibliografisk kontrollert
Jørgensen, D. & Renöfält, B. (2013). Damned if you do, dammed if you don’t: debates on dam removal in the Swedish media. Ecology and Society, 18(1)
Åpne denne publikasjonen i ny fane eller vindu >>Damned if you do, dammed if you don’t: debates on dam removal in the Swedish media
2013 (engelsk)Inngår i: Ecology and Society, ISSN 1708-3087, Vol. 18, nr 1Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Dam removal is an increasingly common practice. Dams are removed for various reasons with safety, economics, and ecosystem restoration being the most common. However, dam removals often cause controversy. Riparian land owners and local communities often have a negative view on removal and the reasons why vary. It may be loss of recreational benefits like swimming and boating, loss of cultural and historical context tied to the dam, or fear that removal may have a negative effect on aesthetic values. Since controversies are often picked up by local media, and media in itself is an important channel to build support around a cause, the way dam removals are reported and discussed is likely to influence the debate. In this article, we examine the ways in which proponents and opponents of dam removal frame the services provided by two contrasting ecosystems—an existing dam and the potential stream without a dam—by performing a discourse analysis of the reasons given for removal and the reasons presented for the dam to remain in place. Our source material includes web-based newspaper articles and public comments on those articles in four dam removal controversies in Sweden. Our results indicate that public opposition is not based on knowledge-deficiency where more information will lead to better ecological decision-making, as is sometimes argued in dam removal science; it is instead a case of different understandings and valuation of the environment and the functions it provides.

sted, utgiver, år, opplag, sider
The Resilience Alliance, 2013
Emneord
controversies, dam removal, discourse analysis, ecosystem services, newspaper media, Sweden
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-67527 (URN)10.5751/ES-05364-180118 (DOI)000317184800029 ()
Forskningsfinansiär
Swedish Research Council Formas
Tilgjengelig fra: 2013-03-22 Laget: 2013-03-22 Sist oppdatert: 2018-06-08bibliografisk kontrollert
Malm Renöfält, B., Lejon, A. G. .., Jonsson, M. & Nilsson, C. (2013). Long-term taxon-specific responses of macroinvertebrates to dam removal in a mid-sized Swedish stream. Rivers Research and Applications: an international journal devoted to river research and management, 29(9), 1082-1089
Åpne denne publikasjonen i ny fane eller vindu >>Long-term taxon-specific responses of macroinvertebrates to dam removal in a mid-sized Swedish stream
2013 (engelsk)Inngår i: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 29, nr 9, s. 1082-1089Artikkel i tidsskrift (Annet vitenskapelig) Published
Abstract [en]

Dam removal to restore ecologically impaired rivers is becoming increasingly common. While the target often is to facilitate fish migration, dam removal has also been assumed to benefit other types of organisms. Because few studies thus far deal with effects of dam removal on stream macroinvertebrates, and because results have been equivocal, we investigated both short- and longer-term dam-removal effects on downstream macroinvertebrate communities. We did this in a before-and-after study of the removal of a dam located in a south Swedish stream. We sampled the benthic fauna 6 months prior to dam removal and both 6 months and 3.5 years after the dam was removed. We compared species composition, taxonomic richness, total densities, and densities of macroinvertebrate groups before and after dam removal and between downstream and reference sites. We found that dam removal reduced some macroinvertebrate taxa at the downstream site, but we found no effect on community composition. While this corroborates results from previous short-term studies, we also found a reduction of taxonomic richness and that some dam-removal effects persisted or even increased over time. The most likely explanation for the suppression of benthic macroinvertebrate richness following dam removal is a significantly increased sediment transport from the former reservoir, and a subsequent loss of preferred substrates. Our results indicate that adverse dam-removal effects may be long-lasting, but taxon-specific. We therefore call for longer-term studies on a variety of organisms to better understand how dam removal may influence downstream macroinvertebrate communities.

sted, utgiver, år, opplag, sider
John Wiley & Sons, 2013
Emneord
dam removal, river restoration, macroinvertebrate density, taxonomic richness, sediment deposition, long-term effects, Sweden
HSV kategori
Forskningsprogram
biologi
Identifikatorer
urn:nbn:se:umu:diva-55568 (URN)10.1002/rra.2592 (DOI)000325823900002 ()
Tilgjengelig fra: 2012-05-22 Laget: 2012-05-21 Sist oppdatert: 2018-06-08bibliografisk kontrollert
Malm-Renöfält, B., Jansson, R. & Nilsson, C. (2010). Effects of hydropower generation and opportunities for environmental flow management in Swedish riverine ecosystems. Freshwater Biology, 55(1), 49-67
Åpne denne publikasjonen i ny fane eller vindu >>Effects of hydropower generation and opportunities for environmental flow management in Swedish riverine ecosystems
2010 (engelsk)Inngår i: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 55, nr 1, s. 49-67Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Hydropower is often presented as a clean and renewable energy source that is environmentally preferable to fossil fuels or nuclear power. Hydropower production, however, fundamentally transforms rivers and their ecosystems by fragmenting channels and altering river flows. These changes reduce flow velocity and the number of rapids, and reduce or alter wetland, floodplain and delta ecosystems. Dams disrupt dispersal of riverine organisms and sediment dynamics and may alter riverine biodiversity composition and abundance. Freshwater ecosystems now belong among the world's most threatened ecosystems.

Water managers are beginning to recognise the need to combine demands for social and economic development with the protection of the resource base on which socioeconomic benefits rely. Environmental flows can help to balance ecosystem and human needs for water, both when constructing new dams and in re-licensing existing dams.

We briefly review the impacts of hydropower generation on freshwater ecosystems by discussing different types of dams and development, and by providing examples from Sweden of how environmental effects of hydropower production could be mitigated. Special emphasis is given to flow regulation through re-operation of dams.

Regulated rivers in Sweden were developed with little consideration of ecological effects, with most dams lacking migration pathways or minimum flow releases. There is thus a substantial potential for improvement of ecological conditions, such as naturalisation of flow regimes and reestablishment of connectivity, in regulated river reaches but technical hurdles imply major challenges for rehabilitation and mitigation. Most regulated rivers consist of cascades of consecutive reservoirs and impoundments, further constraining possible actions to improve ecological conditions.

Most environmental mitigation measures require flow modifications to serve ecosystems, implying reduced power production. An important challenge for river management is to identify situations where measures involving relatively small production losses can have major ecological advantages.

Climate change during the 21st century is expected to increase runoff in northern and central Sweden and make the annual hydrograph more similar to variation in electricity demand, i.e. a lower spring flood and increased run-off during winter months. This could provide opportunities for operating dams and power stations to the benefit of riverine ecosystems. On the other hand, demands to produce hydropower are likely to increase as fossil fuels are phased out, leading to increased pressures on free-flowing rivers and aquatic ecosystems.

Emneord
dams, environmental flow, hydropower, reservoirs, Sweden
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-30344 (URN)10.1111/j.1365-2427.2009.02241.x (DOI)000272836500004 ()
Tilgjengelig fra: 2009-12-17 Laget: 2009-12-17 Sist oppdatert: 2018-06-08bibliografisk kontrollert
Lejon, A. G. .., Malm Renöfält, B. & Nilsson, C. (2009). Conflicts associated with dam removal in Sweden. Ecology and Society, 14(2), 4
Åpne denne publikasjonen i ny fane eller vindu >>Conflicts associated with dam removal in Sweden
2009 (engelsk)Inngår i: Ecology and Society, ISSN 1708-3087, Vol. 14, nr 2, s. 4-Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The increasing number of deteriorating old dams that need renovation or have lost their function make dam removal a viable management option. There are at least four major reasons for dam removal: safety, law and policy, economy, and ecology. Here we discuss 17 Swedish dams that were recently considered for removal. Because dam removal usually causes controversy, dam removal initiatives may succeed, fail, or result in a compromise such as a bypass channel for migrating fish. We identify and discuss three major obstructions to dam removal: funding, cultural-historical values, and threatened species. To facilitate dam removal, the reasons for, and the effects of, dam removal must be carefully explained, and the public and stakeholders must be kept informed. In complicated cases in which compromise solutions may be the most feasible outcome, the integration of the knowledge of different stakeholders is crucial. The involvement of diverse stakeholders increases their willingness to find compromises, thus avoiding conflicts and failures.

sted, utgiver, år, opplag, sider
Wolfville: The Resilience Alliance, 2009
Emneord
controversies, dam removal, information, obstructions, reservoirs, rivers, stakeholder involvement, Sweden
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-25540 (URN)000278707200016 ()
Tilgjengelig fra: 2009-08-19 Laget: 2009-08-19 Sist oppdatert: 2018-06-08bibliografisk kontrollert
Nilsson, C. & Malm-Renöfält, B. (2009). Mygg och Bti i nedre Dalälven: Utvärdering av ett vetenskapligt uppföljningsprogram. Stockholm: Naturvårdsverket
Åpne denne publikasjonen i ny fane eller vindu >>Mygg och Bti i nedre Dalälven: Utvärdering av ett vetenskapligt uppföljningsprogram
2009 (svensk)Rapport (Annet vitenskapelig)
Abstract [sv]

Denna rapport redovisar uppdraget att granska den vetenskapliga uppföljningen avmyggkontrollprogrammet i nedre Dalälven. Rapporten beskriver hur frågorna iuppföljningsprogrammet besvarats samt diskuterar relevansen av de frågor somingått i uppdraget. Det konstateras att den vetenskapliga uppföljningen av eventuellaeffekter av spridning av Bti brustit i försöksdesign och analys. Det insamladematerialet ger inte underlag för de slutsatser som dragits. De frågor som ingått iuppdraget har därmed inte besvarats på ett vetenskapligt övertygande sätt. Detbedöms inte meningsfullt att fortsätta uppföljningsarbetet i sin nuvarande, begränsadeutformning, inte heller att låta personal som leder den storskaliga bekämpningenutvärdera effekterna av sin egen verksamhet. I stället bör en bred forskningsansatsgöras, inriktad på att förstå inte bara olika effekter av Bti-användningmen även betydelsen av skilda miljöfaktorer för att reglera myggens numerär,myggens roll i ekosystemet, dess historia i regionen samt effekter av olika myggtätheter.Den internationella litteraturen sammanfattas med tonvikten på hälsoeffekterav Bti, ekologiska effekter av Bti, myggresistens mot Bti och Bti-persistens inaturen. Litteraturen ger inte stöd för slutsatsen att Bti-användning skulle vara heltriskfri. I rapporten rekommenderas en närmare undersökning av hur älvens regleradevattenföring – en huvudorsak till myggrikedomen – kan modifieras för attvaraktigt reducera myggmängderna. I väntan på en sådan förändring bör generellbekämpning med Bti tillåtas, även i naturskyddade områden, och staten bör ta ansvarför verksamheten. Ekosystemeffekterna av sådan bekämpning bör följas uppnoga, och bekämpningen bör ändras om oönskade effekter uppträder. De ekonomiska,sociala och medicinska konsekvenser de extremt höga myggmängderna kaninnebära för befolkningen bör studeras närmare, exempelvis olägenheter för jordbruk,turism och skola. Vidare bör ställning tas till huruvida de vanligaste översvämningsmyggornai området, Aedes sticticus och A. vexans, ska betraktas somnaturliga, skyddsvärda komponenter i ekosystemet, eller som invaderande artersom behöver bekämpas för att bevara mer ursprungliga naturvärden. Naturvårdsmyndigheternabör också ta initiativ till en bred informationsinsats för att öka denlokala kunskapsnivån och skapa ett lokalt förankrat förtroende för sin verksamhet.De har en viktig uppgift i att visa att höga naturvärden och mänskligt leverne kankombineras utan att människan ska behöva uppleva naturen som en plåga.

Abstract [en]

This report presents the results of a review of the scientific follow-up studies of themosquito control programme in the lower river Dalälven. The report describes howthe questions in the follow-up programme have been answered and discusses therelevance of presented questions. It is concluded that the scientific follow-up workon eventual effects of the application of Bti has failed in sampling design andanalysis. The collected data do not provide the basis for the conclusions that havebeen drawn. The questions included in the follow-up programme have not beenanswered in a scientifically convincing manner. It is not considered meaningful tocontinue the follow-up work with its present restricted design, nor letting staffleading the large-scale mosquito control evaluate effects of its own activities. Instead,a wider research approach needs to be taken, oriented towards understandingnot only the various effects of Bti treatment but also the role of environmental factorsin regulating mosquito populations, the ecological role of mosquitoes, theirhistory in the region, and the effects of various mosquito densities. The internationalliterature is reviewed with an emphasis on health effects of Bti, ecological effectsof Bti, mosquito resistance to Bti and Bti persistence in the field. The literature doesnot provide support for the conclusion that Bti use is completely harmless. Thereport recommends a closer study of how the regulated river flow – a main cause ofthe mosquito abundance – can be modified to permanently reduce the number ofmosquitoes. Awaiting the realization of such a change a general mosquito controlwith Bti should be allowed, also in nature protected areas, and the state should takeon the responsibility for the actions. The ecosystem effects of such a control shouldbe followed closely, and the control should be modified should such unwantedeffects be revealed. The economic, social and medical consequences the extremelyhigh mosquito abundances can mean for local inhabitants should be studied moreclosely, for example inconveniences for agriculture, tourism and school. Furthermore,it needs to be considered whether the most common mosquito species in thearea, Aedes sticticus and A. vexans, should be viewed as natural ecosystem componentsworthy of protection, or as invasive species that need to be combated to preservemore original natural values. Nature authorities should also take the initiativeto execute a wide information campaign to increase the local knowledge level andto establish a locally rooted confidence for their activities. They have an importanttask in demonstrating how high natural values and human living can be combinedwithout humans experiencing nature as a nuisance.

sted, utgiver, år, opplag, sider
Stockholm: Naturvårdsverket, 2009. s. 38
Serie
Naturvårdsverket Rapport, ISSN 0282-7298 ; 6305
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-32115 (URN)978-91-620-6305-4 (ISBN)
Tilgjengelig fra: 2010-03-02 Laget: 2010-03-02 Sist oppdatert: 2018-06-08bibliografisk kontrollert
Malm-Renöfält, B. & Nilsson, C. (2008). Landscape scale effects of disturbance on riparian vegetation. Freshwater Biology, 53(11), 2244-2255
Åpne denne publikasjonen i ny fane eller vindu >>Landscape scale effects of disturbance on riparian vegetation
2008 (engelsk)Inngår i: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 53, nr 11, s. 2244-2255Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

1. Differing responses in riparian species richness and composition to disturbance have been reported as a possible explanation for the differences along and between rivers. This paper explores the role of physical disturbance in shaping landscape-scale patterns of species distribution in riparian vegetation along a free-flowing river in northern Sweden.

2. To test whether sensitivity to disturbance varies across large landscapes, we experimentally disturbed riparian vegetation along an entire, free-flowing river by scouring the soil and the vegetation turf, cutting vegetation, applying waterborne plant litter, and after a period of recovery we measured vegetation responses. The experiment was repeated for two consecutive years.

3. We found no significant effect of disturbance on species composition, but all three forms of disturbance significantly reduced species richness. There was no downstream variation in community responses to disturbance but morphological groups of species responded differently to different kinds of disturbance. Graminoids were most resistant, suppressed only by litter burial. All forms of disturbance except cutting reduced the density of herbaceous species, and species density of trees + shrubs and dwarf shrubs was negatively affected by both scouring and cutting. We also evaluated the effects of disturbance in relation to varying levels of species richness. In nearly all cases, responses were significantly negatively correlated with control plot species richness, and relative responses indicated that species-rich plots were less resistant to scouring and cutting.

4. Our results suggest that although all disturbance treatments had an effect on species richness, variation in sensitivity to disturbance is not the most important factor shaping landscape-scale patterns of riparian plant species richness along rivers.

HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-11364 (URN)10.1111/j.1365-2427.2008.02057.x (DOI)000262283200010 ()
Tilgjengelig fra: 2008-12-16 Laget: 2008-12-16 Sist oppdatert: 2018-06-09bibliografisk kontrollert
Nilsson, C. & Malm-Renöfält, B. (2008). Linking flow Regime and water quality in rivers: a challenge to adaptive catchment management. Ecology & society, 13(2), 18
Åpne denne publikasjonen i ny fane eller vindu >>Linking flow Regime and water quality in rivers: a challenge to adaptive catchment management
2008 (engelsk)Inngår i: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 13, nr 2, s. 18-Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Water quality describes the physicochemical characteristics of the water body. These vary naturally with the weather and with the spatiotemporal variation of the water flow, i.e., the flow regime. Worldwide, biota have adapted to the variation in these variables. River channels and their riparian zones contain a rich selection of adapted species and have been able to offer goods and services for sustaining human civilizations. Many human impacts on natural riverine environments have been destructive and present opportunities for rehabilitation. It is a big challenge to satisfy the needs of both humans and nature, without sacrificing one or the other. New ways of thinking, new policies, and institutional commitment are needed to make improvements, both in the ways water flow is modified in rivers by dam operations and direct extractions, and in the ways runoff from adjacent land is affected by land-use practices. Originally, prescribed flows were relatively static, but precepts have been developed to encompass variation, specifically on how water could be shared over the year to become most useful to ecosystems and humans. A key aspect is how allocations of water interact with physicochemical variation of water. An important applied question is how waste releases and discharge can be managed to reduce ecological and sanitary problems that might arise from inappropriate combinations of flow variation and physicochemical characteristics of water. We review knowledge in this field, provide examples on how the flow regime and the water quality can impact ecosystem processes, and conclude that most problems are associated with low-flow conditions. Given that reduced flows represent an escalating problem in an increasing number of rivers worldwide, managers are facing enormous challenges.

Emneord
catchment scale, ecosystem processes, environmental flows, flow regime, rivers, water quality
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-11372 (URN)000262291600040 ()
Tilgjengelig fra: 2008-12-16 Laget: 2008-12-16 Sist oppdatert: 2018-06-09bibliografisk kontrollert
Malm-Renöfält, B., Merritt, D. M. & Nilsson, C. (2007). Connecting variation in vegetation and stream flow: the role of geomorphic context in vegetation response to large floods along boreal rivers. Journal of Applied Ecology, 44(1), 147-157
Åpne denne publikasjonen i ny fane eller vindu >>Connecting variation in vegetation and stream flow: the role of geomorphic context in vegetation response to large floods along boreal rivers
2007 (engelsk)Inngår i: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 44, nr 1, s. 147-157Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]
  1. Flooding governs riparian plant diversity along boreal rivers but the ecological role of extreme floods is only partly understood. We studied the dynamics of riparian plant composition and richness in the free-flowing Vindel River in northern Sweden, and the importance of reach type in sustaining high species richness.
  2. We conducted three surveys of riparian plant species richness over a period of two decades. The first and last of these surveys were conducted 1–3 years after significant flooding and the second was carried out after a period of more moderate flooding.
  3. Our results suggest that extreme floods reduce riparian plant species richness in tranquil (slow-flowing) reaches but that a subsequent period of less extreme flood events facilitates recovery. Tranquil river reaches were also more prone to invasion by ruderal species following major floods. Species richness in turbulent reaches (rapids and runs) remained constant during all surveys. One possible explanation for this pattern is that tranquil reaches become more anoxic during floods because they have more fine-grade soils with lower hydraulic conductivity than turbulent reaches. Anoxic conditions may cause stress and plant death, opening up space for colonization. Turbulent reaches maintain a better oxygenation in the root zone of plants through high groundwater turnover, reducing negative effects of prolonged floods.
  4. The fact that turbulent reaches preserved species richness regardless of flood magnitude suggests that they are important for the resistance of riparian ecosystems to prolonged inundation. In contrast, tranquil reaches, with a higher water-holding capacity, might instead maintain their species richness during drought periods.
  5. Synthesis and applications. Our findings highlight the importance of spatial and temporal variation in riverine plant species richness and composition. To conserve these habitats at a landscape scale, a full range of reach types is necessary to allow for recovery in reaches where species richness has declined. To maintain healthy riparian zones, river managers should focus restoration efforts on interactions between hydrology, geomorphology and biota.
sted, utgiver, år, opplag, sider
Oxford: Blackwell (for the British ecological society), 2007
Emneord
anaerobic, extreme floods, oxidation reduction potential, plant diversity, redox, resistance, riparian vegetation, river, tranquil reaches, turbulent reaches
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-6216 (URN)10.1111/j.1365-2664.2006.01223.x (DOI)000243023600016 ()
Tilgjengelig fra: 2007-12-07 Laget: 2007-12-07 Sist oppdatert: 2018-06-09bibliografisk kontrollert
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