Roland Jansson

Roland Jansson
Umeå University | UMU · Department of Ecology and Environmental Science

Professor of ecology

About

103
Publications
48,134
Reads
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7,894
Citations
Citations since 2017
25 Research Items
3509 Citations
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20172018201920202021202220230100200300400500600
20172018201920202021202220230100200300400500600
Introduction
My main research interest is to understand mechanisms behind variation in species diversity among geographic areas and clades at different spatial and temporal scales. In macroecological research, my main focus is to understand how climate change in Earth’s history has shaped patterns in biodiversity, including global geographic patterns in species richness. At the ecosystem level, I work mainly with streams and rivers. Most projects focus on restoration ecology to conserve riverine species.

Publications

Publications (103)
Article
Full-text available
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...
Article
Full-text available
The definitive version is available at http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-8137. Riparian vegetation is exposed to stress from inundation and hydraulic disturbance, and is often rich in native and alien plant species. We describe 35 traits that enable plants to cope with riparian conditions. These include traits for toleratin...
Article
We present a framework distinguishing three principal controls of speciation rate: rate of splitting, level of persistence, and length of speciation duration. We contend that discussions on diversification become clearer in the light of this framework, because speciation rate variation could be attributed to any of these controls. In particular, we...
Article
We reviewed published phylogenies and selected 111 phylogenetic studies representing mammals, birds, insects, and flowering plants. We then mapped the latitudinal range of all taxa to test the relative importance of the tropical conservatism, out of the tropics, and diversification rate hypotheses in generating latitudinal diversity gradients. Most...
Article
Full-text available
While the environmental correlates of global patterns in standing species richness are well understood, it is poorly known which environmental factors promote diversification (speciation minus extinction) in clades. We tested several hypotheses for how geographic and climatic variables should affect diversification using a large dataset of bird sis...
Article
Full-text available
1. Riparian vegetation supports high biodiversity providing many services and is, therefore, an important landscape element. Riparian ecosystems are subject to numerous pressures leading to population decline and genetic erosion of riparian plants. This may have cascading effects at various ecosystem levels, including decreasing ecosystem services,...
Article
Full-text available
Riparian vegetation supports high biodiversity providing many services and is, therefore, an important landscape element. Riparian ecosystems are subject to numerous pressures leading to population decline and genetic erosion of riparian plants. This may have cascading effects at various ecosystem levels, including decreasing ecosystem services, so...
Technical Report
Full-text available
Vattenkraften är viktig för Sveriges omställning till fossilfri elproduktion. För att öka vattenkraftens hållbarhet som energikälla behövs miljöåtgärder som gör att elproduktionens miljöeffekter minimeras där det är möjligt. Regleringen av vattenflöden leder ofta till att vattendragens ekosystem förändras med förlust av biologisk mångfald och ekosy...
Article
Full-text available
Riparian zones are the paragon of transitional ecosystems, providing critical habitat and ecosystem services that are especially threatened by global change. Following consultation with experts, 10 key challenges were identified to be addressed for riparian vegetation science and management improvement: (1) Create a distinct scientific community by...
Preprint
Full-text available
1. Riparian vegetation supports high biodiversity providing many services and is, therefore, an important landscape element. Riparian ecosystems are subject to numerous pressures leading to population decline and genetic erosion of riparian plants. This may have cascading effects at various ecosystem levels, including decreasing ecosystem services,...
Conference Paper
Riparian vegetation is a key component of the landscape as it supports high biodiversity and provides numerous ecosystem services. On the other hand, riparian ecosystems suffer from numerous anthropogenic pressures. Successful protection and restoration of riparian ecosystems require substantial knowledge of their functioning at all levels of biodi...
Article
Full-text available
1. Riparian zones are vital areas of interaction between land and rivers and are often degraded by several pressures such as urbanisation, intensive agriculture and river engineering works. 2. This policy brief provides five key policy messages and recommendations to be considered by policy-makers, scientists, managers, and stakeholders to enhance...
Article
Full-text available
To enable prioritization among measures for ecological restoration, knowing the expected benefits and consequences of implementation is imperative, but rarely explicitly quantified. We developed a novel method to prioritize among environmental-flow measures to rehabilitate ecosystems in the Ume River catchment in northern Sweden, a river system hea...
Article
Full-text available
Global warming affects plant fitness through changes in functional traits and thereby ecosystem function. Wetlands are declining worldwide, and hence, ecosystem functions linked to wetlands are threatened. We use Caltha palustris “a common wetland plant” to study whether warming affects growth and reproduction differently depending on origin of sou...
Article
Full-text available
The degradation of riparian ecosystems occurring throughout the past decades has motivated efforts aimed at the restoration of these ecosystems. The success of active revegetation approaches to restoration requires appropriate selection of reproductive material, which in turn requires knowledge of seed traits and germination. A. glutinosa (L.) Gaer...
Article
Hydropeaking, defined as rapid and frequent changes in flow to optimize hydropower production, is an increasingly common procedure negatively affecting lotic habitats in riverine ecosystems. An important aspect of hydropeaking is zero-flow events, occurring when hydropower stations are stopped due to low energy demand or low electricity prices. We...
Article
Full-text available
Hydropeaking, defined as frequent and rapid variation in flow in regulated rivers with hydropower plants over a short period of time, usually sub‐daily to weekly, alters hydraulic parameters such as water levels or flow velocity and exerts strong impacts on fluvial ecosystems. We evaluated the effects of hydropeaking on riverbank vegetation, specif...
Poster
Full-text available
Decline of Alnus glutinosa (L.) Gaertn caused by Phytophthora xalni is an emerging threat to riparian ecosystems, from northern to southern Europe. Reported intraspecific variation within this tree species suggests a variation in resistance in response to the pathogen. This work aimed at investigate the different response of A. glutinosa population...
Conference Paper
Full-text available
Riparian vegetation is a major element of the landscape, structuring and modulating ecological functions yet widespread river degradation across Europe is compromising role as a key ecosystem services provider. CONVERGES COST Action intends to identify research and management needs, including how riparian vegetation has been managed, and to transla...
Article
To assess habitat filtering and dispersal limitation in spore plant community assembly using bryophytes on recently emerged land uplift islands as study system. Gulf of Bothnia, northern Europe. Bryophytes, including the spore plant phyla Bryophyta (mosses) and Marchantiophyta (liverworts). The species compositions of 20 coastal land uplift islands...
Article
Full-text available
Climate‐change projections suggest large changes in riverine flow regime, which will likely alter riparian communities. In northern Europe, forecasts propose lower annual spring flood peaks and higher winter flows, resulting in narrower riparian zones. To estimate the impact of climate change on habitat extent of riparian plants, we developed a fra...
Article
Full-text available
Climate change will have large consequences for flooding frequencies in freshwater systems. In interaction with anthropogenic activities (flow regulation, channel restoration and catchment land‐use) this will both increase flooding and drought across the world. Like in many other ecosystems facing changed environmental conditions, it remains diffic...
Article
The latitudinal diversity gradient (LDG) is one of the most widely studied patterns in ecology, yet no consensus has been reached about its underlying causes. We argue that the reasons for this are the verbal nature of existing hypotheses, the failure to mechanistically link interacting ecological and evolutionary processes to the LDG, and the fact...
Research
How individual species and entire ecosystems will respond to future climate change are among the most pressing questions facing ecologists. Past biodiversity dynamics recorded in the paleoecological archives show a broad array of responses, yet significant knowledge gaps remain. In particular, the relative roles of evolutionary adaptation, phenotyp...
Article
Habitat restoration is increasingly undertaken in degraded streams and rivers to help improve biodiversity and ecosystem functioning. Follow-up assessments focused on outcomes for biodiversity have often found scant evidence for recovery, thus raising concerns about the efficacy of habitat restoration for improving ecological integrity. However, re...
Article
Full-text available
Hydropeaking refers to frequent, rapid and short-term fluctuations in water flow and water levels downstream and upstream of hydropower stations. Such fluctuations are becoming increasingly common worldwide and are known to have far-reaching effects on riverine vegetation. Novel hydrology caused by hydropeaking has no natural correspondence in fres...
Article
Earlier snowmelt at high latitudes advances aboveground plant phenology, thereby affecting water, nutrient and carbon cycles. Despite the key role of fine roots in these ecosystem processes, phenological responses to earlier snowmelt have never been assessed belowground. 2.We experimentally advanced snowmelt in two contrasting plant community types...
Article
Full-text available
Are we entering a new ‘Golden Age’ of biogeography, with continued development of infra-structure and ideas? We highlight recent developments, and the challenges and opportunities they bring, in light of the snapshot provided by the 7th biennial meeting of the International Biogeography Society (IBS 2015). We summarize themes in and across 15 sympo...
Article
Full-text available
The ecological effects of stream restoration were evaluated by comparing riparian vegetation, flooding and habitat properties between channelized and two types of restored streams in northern Sweden. Channelized streams were straightened and cleared of in-stream boulders and wood >50 years ago to facilitate timber floating. Basic restoration (perfo...
Article
Full-text available
Recent research predicts that future climate change will result in substantial biodiversity loss associated with loss of habitat for species. However, the magnitude of the anticipated biodiversity impacts are less well known. Studies of species vulnerability to climate change through species distribution models are often limited to assessing the ex...
Conference Paper
One effect of hydropower is hydropeaking, caused by sub-daily fluctuations of water-level because of variable turbine operation. We aim to investigate the effects of hydropeaking on the recruitment and performance of riparian vegetation, in order to identify (1) the stages in the plants’ life-cycle critically affected by hydropeaking, (2) hydropeak...
Conference Paper
Full-text available
Many hydropower installations are producing electricity using hydropeaking. Hydropeaking refers to rising or falling discharges caused either by the turning on or off of hydro-turbines to generate electricity according to variations in the market demand. As a result, downstream and upstream river hydrology is altered due to unnatural, rapid and sig...
Article
Full-text available
The distribution of water across landscapes affects the diversity and composition of ecological communities , as demonstrated by studies on variation in vascular plant communities along river networks and in relation to groundwater. However, non-vascular plants have been neglected in this regard. Bryophytes are dominant components of boreal flora,...
Article
Full-text available
Quaternary glacial cycles have shaped the geographic distributions and evolu-tion of numerous species in the Arctic. Ancient DNA suggests that the Arcticfox went extinct in Europe at the end of the Pleistocene and that Scandinaviawas subsequently recolonized from Siberia, indicating inability to track itshabitat through space as climate changed. Us...
Data
Table S1. Predictor variables used in the ecological niche models. Figure S1. MOP and MESS model transference analyses.
Data
Appendix S1. Alternative results including further occurrence and variable reduction steps.
Article
Full-text available
Humans depend on services provided by ecosystems, and how services are affected by climate change is increasingly studied. Few studies, however, address changes likely to affect services from seminatural ecosystems. We analyzed ecosystem goods and services in natural and seminatural systems, specifically how they are expected to change as a result...
Article
Channelization of streams and rivers to facilitate timber floating has cut off riparian zones from the channel, covered them with coarse sediment and resulted in less flooding. Restoration measures aiming to counteract these impacts are expected to create a higher, more natural hydrological variability and enhance site quality for riparian plants....
Technical Report
Full-text available
Climate change may affect biodiversity to a large extent. Its effects have already caused shifts in species distributions and even species extinctions. Since especially high latitude regions are expected to be affected, this publication assesses the impact of future climate change on the biodiversity in the Barents Region (northern parts of Norway,...
Article
Full-text available
Many streams that were channelized to facilitate timber floating in northern Sweden, have in recent years been restored by returning coarse sediment (cobbles and boulders) to the channel and reconnecting riparian with instream habitats. We asked if such restoration measures affect germination and survival of plants in the riparian zone, and if such...
Article
Full-text available
The ecological restoration of streams in Sweden has become increasingly important to counteract effects of past timber floating. In this study, we focused on the effect on riparian soil properties after returning coarse sediment (cobbles and boulders) to the channel and reconnecting riparian with in-stream habitats. Restoration increases habitat av...
Conference Paper
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...
Article
How does germination and establishment of non‐resident plant species differ among major types of wetland ecosystems in boreal forest landscapes? We evaluated the invasibility of three boreal‐forest wetland types by sowing seeds of six species from the native species pool and followed germination and survival for 3 yr. All species were able to invad...
Article
Full-text available
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...
Article
Ecological restoration increases, but evaluation of restoration efforts is inadequate because reliable performance indicators are lacking. As plants are important actors in ecological restoration, we suggest that they be used as metres, i.e. phytometers, of restoration success. Phytometer plants are transplanted to different conditions to integrate...
Article
Full-text available
The opportunity to reflect broadly on the accomplishments, prospects, and reach of a field may present itself relatively infrequently. Each biennial meeting of the International Biogeography Society showcases ideas solicited and developed largely during the preceding year, by individuals or teams from across the breadth of the discipline. Here, we...
Article
Full-text available
Riparian zones in boreal areas such as humid landscapes on minerogenic soils are characterized by diverse, productive, and dynamic vegetation which will rapidly react to climate change. Climate-change models predict that in most parts of the boreal region these zones will be affected by various combinations of increased temperature, less seasonal v...
Article
Full-text available
Arctic and subarctic (i.e., [sub]arctic) ecosystems are predicted to be particularly susceptible to climate change. The area of tundra is expected to decrease and temperate climates will extend further north, affecting species inhabiting northern environments. Consequently, species at high latitudes should be especially susceptible to climate chang...
Article
Full-text available
Species distribution modeling (SDM) is an increasingly important tool to predict the geographic distribution of species. Even though many problems associated with this method have been highlighted and solutions have been proposed, little has been done to increase comparability among studies. We reviewed recent publications applying SDMs and found t...
Data
Number of studies using SDMs as listed in the Web of Knowledge from 1992–2010. (TIF)
Data
Definitions of terms we used in species’ distribution modeling. (DOC)
Data
The analyses of a subsample of papers using SDM. A. Layout of the published ecological applications in which SDMs are used. B. Proportion of SDM publications reporting on species’ occurrences, bias in the input data, geographical extent, maximum probability distribution, thresholds used to transform continuous probability surfaces to binary surface...
Article
Aim With climate change, reliable predictions of future species geographic distributions are becoming increasingly important for the design of appropriate conservation measures. Species distribution models (SDMs) are widely used to predict geographic range shifts in response to climate change. However, because species communities are likely to chan...
Article
1. Riparian plant communities are primarily structured by the hydrological regime of the stream. Models of climate change predict increased temperatures and changed patterns of precipitation that will alter the flow of rivers and streams with consequences for riparian communities. In boreal regions of Europe, stream flows will exhibit earlier sprin...
Article
Full-text available
Between 1850 and 1970, rivers throughout Sweden were channelized to facilitate timber floating. Floatway structures were installed to streamline banks and disconnect flow to secondary channels, resulting in simplified channel morphologies and more homogenous flow regimes. In recent years, local authorities have begun to restore channelized rivers....
Conference Paper
Background/Question/Methods To understand how and why alien species can dominate and change the communities and ecosystems they invade, ecologists need to first understand the processes that enable and drive successful invasion. Invasion ecology includes myriad hypotheses. Evidence suggests that most of these can explain the success of some invad...
Conference Paper
Background/Question/Methods Previous literature reviews show how trophic cascades are, on average, stronger in the tropics. A possible reason might be that tropical species are, on average, more specialized with more co-evolved interspecific interactions. This study aims to tie the strength of trophic interactions to trophic niche specialization...
Article
1. Many rivers and streams experience pronounced ice dynamics caused by the formation of anchor and frazil ice, leading to flooding and disturbance of riparian and aquatic communities. However, the effects of dynamic ice conditions on riverine biota are little known. 2. We studied the formation of anchor ice in natural streams over 2 years and asse...
Article
Climate change is expected to alter the magnitude and variation of flow in streams and rivers, hence providing new conditions for riverine communities. We evaluated plant ecological responses to climate change by transplanting turfs of riparian vegetation to new elevations in the riparian zone, thus simulating expected changes in water-level variat...
Article
Full-text available
The spatial distribution and temporal availability of propagules fundamentally constrain plant community development. This study experimentally tested several hypotheses about the relative roles of wind and water dispersal in colonization and development of riparian communities along rivers. Through controlling the source of propagules (dispersed b...
Article
Hydrochory, or the passive dispersal of organisms by water, is an important means of propagule transport, especially for plants. During recent years, knowledge about hydrochory and its ecological consequences has increased considerably and a substantial body of literature has been produced. Here, we review this literature and define the state of th...
Article
Full-text available
Global warming will continue, and the Arctic is expectedto warm at twice the global average rate (Intergovern-mental Panel on Climate Change 2007). The most pro-nounced changes will occur during winter with increasedprecipitation, more precipitation falling as rain, and ashorter snow period (Intergovernmental Panel on ClimateChange 2007; Roderfeld...
Article
Full-text available
1. 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...
Article
Full-text available
Human-induced climate change may threaten a large proportion of Earth's biota, but the uncertainties involved in projecting the future geographical distributions of species make quantitative predictions of extinction risk difficult to make. I discuss how insight from recent advances in macroecology and knowledge about species responses to past clim...