Johan S Eklöf

Johan S Eklöf
Stockholm University | SU · Department of Ecology, Environment and Plant Sciences

PhD and Docent in Marine Ecology
Associate Professor in Marine Biology

About

110
Publications
32,268
Reads
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2,671
Citations
Introduction
I'm an ecosystems ecologist generally interested in the causes and consequences of biodiversity, from genes to landscapes. I'm particularly interested in i) how interactions between organisms change with environmental conditions, ii) factors influencing the relative importance of biotic vs. abiotic drivers of ecosystem processes, and iii) how we can best manage ecosystems to sustain their services to humans in a rapidly changing world.
Additional affiliations
December 2017 - present
Stockholm University
Position
  • Professor (Associate)
December 2013 - November 2017
Stockholm University
Position
  • Associate Senior Lecturer in Macrophyte ecology
December 2013 - November 2017
Stockholm University
Position
  • Assistant professor in Macrophyte ecology
Education
January 2004 - February 2008
Stockholm University
Field of study
  • Seagrass ecology
August 1998 - September 2003
Stockholm University
Field of study
  • Biology

Publications

Publications (110)
Article
Seagrass meadows are vital ecosystems in coastal zones worldwide, but are also under global threat. One of the major hurdles restricting the success of seagrass conservation and restoration is our limited understanding of ecological feedback mechanisms. In these ecosystems, multiple, self-reinforcing feedbacks can undermine conservation efforts by...
Article
Full-text available
1.Seagrass and seaweed habitats constitute hotspots for diversity and ecosystem services in coastal ecosystems. These habitats are subject to anthropogenic pressures, of which eutrophication is one major stressor. Eutrophication favours fast-growing ephemeral algae over perennial macroalgae and seagrasses, causing habitat degradation. However, chan...
Article
Nutrient pollution and reduced grazing each can stimulate algal blooms as shown by numerous experiments. But because experiments rarely incorporate natural variation in environmental factors and biodiversity, conditions determining the relative strength of bottom-up and top-down forcing remain unresolved. We factorially added nutrients and reduced...
Article
Full-text available
In many coastal areas, marine ecosystems have shifted into contrasting states having reduced ecosystem services (hereafter called degraded). Such degraded ecosystems may be slow to revert to their original state due to new ecological feedbacks that reinforce the degraded state. A better understanding of the way human actions influence the strength...
Article
Full-text available
Ecosystems are simultaneously affected by biodiversity loss and climate change, but we know little about how these factors interact. We predicted that climate warming and CO (2) -enrichment should strengthen trophic cascades by reducing the relative efficiency of predation-resistant herbivores, if herbivore consumption rate trades off with predatio...
Article
Seagrass meadows, like other tropical coastal ecosystems, are highly productive and sustain millions of people worldwide. However, the factors that govern the use of seagrass as a fishing habitat over other habitats are largely unknown, especially at the household scale. Using socioeconomic factors from 147 villages across four countries within the...
Article
Under rapid environmental change, opportunistic species may exhibit dramatic increases in response to the altered conditions, and can in turn have large impacts on the ecosystem. One such species is the three-spined stickleback (Gasterosteus aculeatus), which has shown substantial increases in several aquatic systems in recent decades. Here, we rev...
Article
Full-text available
While considerable evidence exists of biogeographic patterns in the intensity of species interactions, the influence of these patterns on variation in community structure is less clear. Studying how the distributions of traits in communities vary along global gradients can inform how variation in interactions and other factors contribute to the pro...
Article
Full-text available
Ecosystem multifunctionality is an increasingly popular concept used to approximate multifaceted ecosystem functioning, which in turn may help advance ecosystem-based management. However, while experimental studies have shown a positive effect of diversity on multifunctionality, observational studies from natural systems—particularly aquatic—are sc...
Article
Full-text available
With the increase of recreational boating activity and development of boating infrastructure in shallow, wave-protected areas, there is growing concern for their impact on coastal ecosystems. In order to properly assess the effects and consider the potential for recovery, it is important to investigate microbial and meiofaunal communities that unde...
Article
Full-text available
Intraspecific niche differentiation can contribute to population persistence in changing environments. Following declines in large predatory fish, eutrophication, and climate change, there has been a major increase in the abundance of threespine stickleback (Gasterosteus aculeatus) in the Baltic Sea. Two morphotype groups with different levels of b...
Article
Full-text available
Seagrass meadows constitute important carbon sinks, and the ongoing global loss of seagrass habitats raises concerns about the release of carbon stored in their sediments. However, the actual consequences of seagrass loss for the release of carbon and nutrients remain unclear. Here, we take advantage of well‐documented historic losses of eelgrass (...
Article
Full-text available
Declines of large predatory fish due to overexploitation are restructuring food webs across the globe. It is now becoming evident that restoring these altered food webs requires addressing not only ecological processes, but evolutionary ones as well, because human‐induced rapid evolution may in turn affect ecological dynamics. We studied the potent...
Article
Full-text available
Seagrasses – a group of foundation species in coastal ecosystems – provide key habitat for diverse and abundant faunal assemblages and support numerous ecosystem functions and services. However, whether the habitat role of seagrasses is influenced by seagrass diversity, by dominant species or both, remains unclear. To that end, we sought to investi...
Article
Full-text available
In this study we examined abiotic and biotic factors that could potentially influence the presence of a non-indigenous seaweed, Eucheuma denticulatum, in two locations, one outside (Kane’ohe Bay, Hawai’i, USA) and one within (Mafia Island, Tanzania) its natural geographical range. We hypothesized that the availability of hard substrate and the amou...
Article
Full-text available
Ecosystems worldwide depend on habitat-forming foundation species that often facilitate themselves with increasing density and patch size, while also engaging in facultative mutualisms. Anthropogenic global change (e.g., climate change, eutrophication , overharvest, land-use change), however, is causing rapid declines of foundation species-structur...
Article
Full-text available
Ocean climate change strongly affects organisms and ecosystems, and the causes, consequences, and underlying mechanisms need to be documented. In the Baltic Sea, a marginal sea under severe eutrophication stress, a longer productive season, and changes in the phytoplankton community over the last few decades have likely impacted diet and condition...
Article
Full-text available
Regime shifts in ecosystem structure and processes are typically studied from a temporal perspective. Yet, theory predicts that in large ecosystems with environmental gradients, shifts should start locally and gradually spread through space. Here we empirically document a spatially propagating shift in the trophic structure of a large aquatic ecosy...
Technical Report
Full-text available
SUMMARY: Several coastal fish species in the Baltic Sea are of freshwater origin and reproduce in nearshore wave-sheltered waters, shallow bays and wetlands. Historical drainage of land together with coastal development and eutrophication have led to losses of fish spawning and nursery areas, which together with fishing have contributed to decreas...
Preprint
Full-text available
Declines of large predatory fish due to overexploitation are restructuring food webs across the globe. It is now becoming evident that restoring these altered food webs requires addressing not only ecological processes, but evolutionary ones as well, because human-induced rapid evolution may in turn affect ecological dynamics. In the central Baltic...
Article
Effects of climate change on natural ecosystems can be mediated by ecological processes, but also by rapid evolutionary adaptations and/or non‐heritable trait changes in organisms. So far, most studies testing the importance of inter‐ versus intraspecific changes for how communities and their functioning responds to climate change are either short‐...
Article
Full-text available
In a changing environment, there is an increasing interest to monitor ecosystems to understand their responses to environmental change. Seagrass meadows are highly important ecosystems that are under constant pressure from human activities and climate impacts, with marked declines observed worldwide. Despite increasing efforts, monitoring of multis...
Article
Full-text available
Jacobson P., Bergström U. & Eklöf J. 2019 Size-dependent diet composition and feeding of Eurasian perch (Perca fluviatilis) and northern pike (Esox lucius) in the Baltic Sea. Boreal Env. Res. 24: 137-153. To understand food web dynamics, knowledge about factors influencing trophic interactions is fundamental. Using stomach content analysis, we inve...
Article
Full-text available
Seagrasses, flowering marine plants that form underwater meadows, play a significant global role in supporting food security, mitigating climate change and supporting biodiversity. Although progress is being made to conserve seagrass meadows in select areas, most meadows remain under significant pressure resulting in a decline in meadow condition a...
Article
Despite the importance of coastal ecosystems for the global carbon budgets, knowledge of their carbon storage capacity and the factors driving variability in storage capacity is still limited. Here we provide an estimate on the magnitude and variability of carbon stocks within a widely distributed marine foundation species throughout its distributi...
Article
Self‐facilitation allows populations to persist under disturbance by ameliorating experienced stress. In coastal ecosystems, eutrophication and declines of large predatory fish are two common disturbances that can synergistically impact habitat‐forming plants by benefitting ephemeral algae. In theory, density‐dependent intraspecific plant facilitat...
Article
Full-text available
Recreational boating increases globally and associated moorings are often placed in vegetated habitats important for fish recruitment. Meanwhile, assessments of the effects of boating on vegetation, and potential effects on associated fish assemblages are rare. Here, we analysed (i) the effect of small-boat marinas on vegetation structure, and (ii)...
Article
Form–function relationships in plants underlie their ecosystem roles in supporting higher trophic levels through primary production, detrital pathways, and habitat provision. For widespread, phenotypically-variable plants, productivity may differ not only across abiotic conditions, but also from distinct morphological or demographic traits. A singl...
Article
Full-text available
Multi-trophic conservation and management strategies may be necessary if reciprocal linkages between primary producers and their consumers are strong. While herbivory on aquatic plants is well-studied, direct top-down control of seagrass populations has received comparatively little attention, particularly in temperate regions. Herein, we used qual...
Article
Full-text available
Latitudinal gradients in species interactions are widely cited as potential causes or consequences of global patterns of biodiversity. However, mechanistic studies documenting changes in interactions across broad geographic ranges are limited. We surveyed predation intensity on common prey (live amphipods and gastropods) in communities of eelgrass...
Article
Full-text available
The three-spined stickleback (Gasterosteus aculeatus L., hereafter ‘stickleback’) is a common mesopredatory fish in marine, coastal and freshwater areas. In large parts of the Baltic Sea, stickleback densities have increased >10-fold during the last decades, and it is now one of the dominating fish species both in terms of biomass and effects on lo...
Data
Summary of some studies on three-spined stickleback diet. (DOCX)
Data
Taxa found in three-spined stickleback stomachs as revealed by DNA metabarcoding (Primates and Aves excluded). Items in italics were considered as secondary/ accidental prey %Fbar- frequency of occurrence (percentage of stomachs in which a prey was present). (DOCX)
Data
Diet of three-spined stickleback as revealed by visual stomach content analysis. %Fvis—the percentage of stomachs in which a prey was present. (DOCX)
Data
Stickleback size (total length, mm) distribution in a sample. (TIF)
Data
Gammaridae size distribution in the bays studied. (TIF)
Data
Comparison of quantification from OTU reads and results of visual stomach content analysis. (DOCX)
Article
Full-text available
Field surveys often show that high water turbidity limits cover of aquatic vegetation, while many small-scale experiments show that vegetation can reduce turbidity by decreasing water flow, stabilizing sediments, and competing with phytoplankton for nutrients. Here we bridged these two views by exploring the direction and strength of causal relatio...
Article
Full-text available
Marine protected areas (MPAs) have been shown to increase long-term temporal stability of fish communities and enhance ecosystem resilience to anthropogenic disturbance. Yet, the potential ability of MPAs to buffer effects of environmental variability at shorter time scales remains widely unknown. In the tropics, the yearly monsoon cycle is a major...
Data
Partial regression plots of the significant relationships and tendencies from the regional scale analysis of sediment-driven turbidity. The sediment-driven turbidity is the residuals of turbidity predicted by fluorescence. The relationships shown are from the two best fitting models (model 3 and 4). Nitrogen load is log10-transformed, and vegetatio...
Data
Original field data, including metadata. Field data of vegetation cover, turbidity, fluorescence, salinity and dissolved nutrients at station level (N = 201) and bay level data (n = 32) of topographic openness, retention time and latitude. For more detailed descriptions of the variables see the metadata sheet in S1 Appendix. (XLSX)
Data
Results from the directional separation test for model 1–4 at local and regional scale. At regional scale averages/bay were used. Bold numbers indicate the best fitting simplified models. Models that differ with less than 4 units of AIC are considered to fit the data equally well. (PDF)
Data
Description of the gillnet fishing in spring and how the relationship between turbidity and benthivorous fish was tested. (PDF)
Data
Correlation matrix for the regional scale data, with means per bay (n = 32). Pearson correlation coefficients are shown below the diagonal, p-values are shown above the diagonal. Bold numbers show significant correlations. Topographic openness, retention time, nitrogen load, fluorescence and turbidity are log10-transformed, vegetation cover is squa...
Data
Average CPUE over all bays of the fish species caught in gillnets in spring. The species are sorted after the highest average CPUE. Benthivorous fish species are marked in bold. (PDF)
Data
Results from the analyses of seasonal differences in variables. The table shows the likelihood ratio test statistic (LRT), its p-value, the estimate and standard error of the fixed effect “Season” (level: summer) of the mixed models, for all variables at regional scale (n = 32) and local scale (N = 201). (PDF)
Data
Piecewise structural equation modelling. (PDF)
Data
Slopes of correlation between species pairs. Slopes of correlation between all possible species pairs in (A) MPAs and (B) open-access sites. Slopes are coloured by sign and management level (Green: negative + MPA; Blue: positive + MPA; Red: negative + Open-access area; Orange: positive + Open-access area). Black lines represent the mean slopes of c...
Article
Full-text available
Government-managed marine protected areas (MPAs) can restore small fish stocks, but have been heavily criticized for excluding resource users and creating conflicts. A promising but less studied alternative are community-managed MPAs, where resource users are more involved in MPA design, implementation and enforcement. Here we evaluated effects of...
Data
Data used for univariate analyses. (XLSX)
Data
Comparison of MPA effects based on A) time series within MPAs and B) site-for-time surveys between MPAs. Relative increase in mean total fish biomass based on time series analysis within large government MPAs (data from McClanahan and Graham 2005) and site-for-time survey (this study) show similar results and suggest that time since closure is an i...
Data
Relationships between fish size and market value. Linear relationships between fish size (standard length, cm) and market value (price in Kenyan shilling, Ksh/kg) for five value groups. (DOCX)
Data
Data used for multivariate analyses. (XLSX)
Data
List of fish taxa found during the study in the six study areas in Kenya. (DOCX)