Peer-reviewed publications

A list including citations is available viGoogle scholar
C.H.A. van Leeuwen, N. Villar, I. Mendoza Sagrera, A.J. Green, E.S. Bakker, M.B. Soons, M.Galetti, P.A. Jansen, B.A. Nolet, L. Santamaría (2022)
A Seed Dispersal Effectiveness framework across the mutualism–antagonism continuum
Content: Many angiosperms rely on vertebrates for seed dispersal via gut passage, an interaction that has been traditionally classified as a mutualism. The seed dispersal effectiveness (SDE) framework provides a mechanistic approach to evaluate evolutionary and ecological characteristics of animal-mediated seed dispersal, by synthesising the quantity and the quality of the dispersal that a plant species receives from each of its animal dispersers. However, the application of the SDE framework has been largely restricted to plant–frugivore interactions, whereas animal-mediated seed dispersal results from plant–disperser interactions that cover a continuum from pure mutualisms to antagonisms. This biases ecological and evolutionary knowledge on plant–disperser interactions. Here, we propose an extended SDE framework (‘eSDE') that allows comparing plant–disperser interactions in the full mutualism–antagonism continuum ranging from pure mutualisms (frugivores) to conditional mutualisms (scatter-hoarding granivores and folivores) and antagonisms (pure granivores).
H. Jin, C.H.A. van Leeuwen, R.J.M. Temmink, E.S. Bakker (2022)
Impacts of shelter on the relative dominance of primary producers and trophic transfer efficiency in aquatic food webs: Implications for shallow lake restoration
Freshwater Biology
Content: We studied the impact of wind on aquatic primary producers and transfer efficiency of this energy to higher trophic levels. We hypothesised that reducing wind-induced turbulence would lead to higher trophic production in shallow lakes. We tested our hypothesis by creating mesocosms in the shallow waters of the restoration project "Marker Wadden" in lake Markermeer in the Netherlands, and studying the effects of this artifically created shelter on aquatic food webs. Creation of shelted facilitated submerged macrophytes, increased Gastropoda densities and increased trophic transfer efficiency between phytoplankton and zooplankton. Creating shelter in shallow lake ecosystems suffering from strong wind-effects can have positive effects on food availability for higher trophic levels, such as fish and water birds.
M.J. Navarro‐Ramos, A.J. Green, A. Lovas‐Kiss, J. Roman, K. Brides, and C.H.A. van Leeuwen (2022)
A predatory waterbird as a vector of plant seeds and aquatic invertebrates
Freshwater Biology
Content: We studied the potential of predatory waterbirds to disperse aquatic organisms via secondary dispersal, using the grey heron Ardea cinerea in Europe as an example species. Grey herons regurgitate undigestible remains of their prey in pellets. Examinations of these pellets collected throughout northwestern Europe showed that a wide variety of aquatic invertebrates and plant seed is dispersed by herons in these pellets. Plant taxa were dominated by Caryophyllaceae, Cyperaceae, Juncaceae, and Poaceae, with 24 species from the littoral zone (Ellenberg moisture values of 7–12) and 21 terrestrial species (Ellenberg moisture values of 4–6). Intact invertebrate propagules were found in 30% of the pellets, dominated by Cladocera and Bryozoa. Our findings showcase the potential of predatory waterbirds as vectors of plants and invertebrates, and how they may facilitate connectivity between freshwater and terrestrial habitats.
H. Jin, C.H.A. van Leeuwen, D.B. van de Waal, E.S. Bakker (2022)
Impacts of sediment resuspension on phytoplankton biomass production and trophic transfer: Implications for shallow lake restoration
Science of The Total Environment
Content: We quantified the effects of reducing wind-induced resuspension in shallow lakes as a form of shallow lake restoration. We varied resuspension levels in an indoor microcosm experiment, and monitored the effects on phytoplankton, benthic algae and zooplankton at different temperatures. Reducing resuspension decreased nutrient concentrations and phytoplankton biomass build-up, but increased light availability, benthic algae biomass and zooplankton. This suggests that creating sheltered areas in shallow lakes suffering from wind effects can be effective in increasing trophic transfer of phytoplankton to zooplankton, and can stimulate secondary production and higher trophic levels. We link these results to Marker Wadden, a large-scale restoration project in Lake Markermeer in the Netherlands.
R.J.M. Temmink, M. van den Akker, C.H.A. van Leeuwen, Y. Thöle, H. Olff, V.C. Reijers, S.T.J. Weideveld, B.J.M. Robroek, L.P.M. Lamers, E.S. Bakker (2022)
Herbivore exclusion and active planting stimulate reed marsh development on a newly constructed archipelago,
Ecological Engineering    pdf
Content: We conclude that the establishment of reed marshes can strongly benefit from excluding herbivores and the introduction of reed, and that otherwise different vegetation types may establish and may establish more slowly. This is especially relevant when restoring or creating new wetland ecosystems, for which vegetation development is often a crucial first step. Our work illustrates how active management of vegetation development has the potential to benefit novel ecosystems.

C.H.A. van Leeuwen, R.J.M. Temmink, H. Jin, Y. Kahlert, B.J.M. Robroek, M.P. Berg, L.P.M. Lamers, M. van den Akker, R. Posthoorn, A. Boosten, H. Olff, E.S. Bakker. (2021)
Enhancing ecological integrity while preserving ecosystem services: constructing soft-sediment islands in a shallow lake
Ecological Solutions and Evidence    pdf
Classical restoration of  degrading freshwater ecosystems can lead to societal opposition, if returning to a former ecosystem state affects previously acquired ecosystem services. Innovative nature-based solutions are therefore needed that enhance natural values in ecosystems, without affecting existing services. We present the first results of a large-scale project - called the "Marker Wadden" - which aims to increase the ecological integrity of a human-modified freshwater lake while maintaining its services to humans. Within 4 years, the Marker Wadden project shows how forward-looking sustainable development of lake ecosystems using a rewilding approach can enhance natural processes.

Martín Vélez, V; Van Leeuwen, C.H.A.; Sánchez, M.; Hortas, F.; Shamoun-Baranes, J.; Thaxter, C.; Lens, L.; Camphuysen, C. & A. J. Green (2021)
Spatial patterns of weed dispersal by wintering gulls within and beyond an agricultural landscape
Journal of Ecology
Gulls can disperse weed plants over long distances across a mosaic of habitats. This implies exchange of weed plant species between human‐dominated and natural areas by waterbirds as dispersal vectors. This spatial study highlights the importance of non‐frugivorous birds for long‐distance plant dispersal, which is generally an overlooked mechanism in studies aiming to predict and manage expansion of weed plants.

Mulder, A.J.E., van Aalderen, R. & C.H.A. van Leeuwen (2021)
Tracking temperate fish reveals their relevance for plant seed dispersal
Functional Ecology  pdf
We calculated the first realistic dispersal kernels for plant seeds dispersed by temperate fish species, by combining acoustic tracking with laboratory experiments. This novel approach increases our understanding of plant-animal interactions in an understudied system. We draw conclusions about maximum dispersal distances, intraspecific variation, seasonality and effects of anthropogenic barriers.

Petruzzella, A., T.A. da S. S. R. Rodrigues, C.H.A. van Leeuwen, F. de Assis Esteves, M. Paulo Figueiredo-Barros & E.S. Bakker (2020)
pecies identity and diversity effects on invasion resistance of tropical freshwater plant communities
Scientific Reports 10, 5626 pdf
Content: We investigated how native plant community presence and diversity - and the presence of native phylogenetically closely related species to invading plant species - affect the establishment success of invading tropical freshwater submerged plant species. The presence of a native plant community suppressed the growth of the invading species (Hydrilla verticillata), but did not prevent its colonisation. Invader growth was negatively affected by native plant productivity, but independent of native species richness and phylogenetic relatedness to the invader. This illustrates that resistance provided by tropical freshwater submerged plant communities to invasive species contrasts to resistance described for other ecosystem types.

Zhang, P., van Leeuwen, C.H.A., Bogers, D. Poelman, M. Xu, J. & E.S. Bakker (2020)
Ectothermic omnivores increase herbivory in response to rising temperatures
doi: 10.1111/oik.07082 pdf
Content: Ectothermic herbivores and carnivores generally ingest more food with rising temperature as their metabolic rates increase with rising temperature. We hypothesized that rising temperature would increase herbivory of ectothermic omnivores, and confirmed this hypothesis in a freshwater model system with the pond snail Lymnaea stagnalis. A literature survey furthermore suggested that aquatic ectothermic omnivores might commonly increase herbivory with rising temperatureWe conclude that future global warming will most likely alter food webs by increasing the top–down control of aquatic herbivores and omnivores on primary producers.

Petruzzella, A., van Leeuwen, C.H.A., van Donk, E. & E.S. Bakker (2020)
Direct and indirect effects of native plants and herbivores on biotic resistance to alien aquatic plant invasions

Journal of Ecology doi10.1111/1365-2745.13380
Biotic resistance to alien plant invasions is mainly determined by ecological interactions in two layers of the food web: competition with native plant species and herbivory by native herbivores. While the direct effect of native plants on alien plant performance via competition has been well documented across ecosystems, less is known about the direct and indirect effects of herbivores in providing biotic resistance. We found experimental evidence for biotic resistance through competition by native plant species. However, we show that in freshwater ecosystems herbivores can indirectly facilitate invasions by promoting invader growth through selective feeding on filamentous algae. This illustrates the importance of indirect interactions to understand biotic resistance in natural ecosystems.

Van Leeuwen, C.H.A., Tella, J. L. & Green, A. J. (2020)
Editorial: Animal-Mediated Dispersal in Understudied Systems.

Frontiers in Ecology and Evolution Ebook available here

Animals disperse smaller organisms by ingesting, transporting and egesting propagules such as plant seeds, fruits, small invertebrates and algae (internal transport), or by carrying propagules attached to their exterior (external transport). Animal-mediated dispersal is generally well studied, but most previous work focused on only a handful of species networks. We initiated a Research Topic in which we gathered studies on animal-mediated dispersal that involved poorly studied and previously overlooked propagules and disperser animals. We hope this collection of 14 new papers will broaden our knowledge beyond the currently most-studied systems, and will inspire future work on contrasts and similarities across study systems.

Zhang P., Kuramae A., van Leeuwen C.H.A., Velthuis M., van Donk E., Xu J. and Bakker E.S. (2020)
Interactive effects of rising temperature and nutrient enrichment on aquatic plant growth, stoichiometry, and palatability
Frontiers in Plant Science 11:58. doi: 10.3389/fpls.2020.00058
Temperature rise and eutrophication are global environmental changes that can affect aquatic plants and their palatability to herbivores. However, these factors often change simultaneoulsy. We studied how temperature rise and eutrophication interactively affect aquatic plants. We tested the hypotheses that (1) plant growth rates increase faster with rising temperature in nutrient-rich than nutrient-poor sediments; (2) plant carbon to nutrient ratios respond differently to rising temperatures at contrasting nutrient conditions of the sediment; (3) external nutrient loading to the water column limits the growth of plants and decreases plant C:nutrient ratios; and that (4) changes in plant stoichiometry affect plant palatability.

Van Leeuwen, C.H.A., Tella, J. L. & Green, A. J. (2020)
Editorial: Animal-Mediated Dispersal in Understudied Systems.
Frontiers in Ecology and Evolution doi: 10.3389/fevo.2019.00508
Editorial publication outlining seven key lessons we can learn from the 14 new publications we published in our Special Issue on "Animal-mediated dispersal in understudied systems".

Martín-Vélez, V., Mohring, B., van Leeuwen, C. H. A., Shamoun-Baranes, J., Thaxter, C. B., Baert, J. M., Camphuysen, C. J. & Green, A. J. (2019)
Functional connectivity network between terrestrial and aquatic habitats by a generalist waterbird, and implications for biovectoring.
Science of the Total Environment 135886.
The functional connectivity network of gulls wintering in Southern Spain was found to functionally link seven habitat types. Dominant habitat types were ricefields and rubbish dumps (landfills). High connectivity of terrestrial landfills with wetlands suggests that waterbirds can transport nutrients, contaminants and antibiotic resistance to and from protected wetland habitats.

J.P van Zuidam*, C.H.A. van Leeuwen*, E.S. Bakker, J.T.A. Verhoeven, S. IJff, E.T.H.M. Peeters, B.G. van Zuidam, M.B. Soons (2019) *shared first authors
Plant functional diversity and nutrient availability can improve restoration of floating fens via facilitation, complementarity and selection effects

Journal of Applied Ecology pdf
Content: Peat‐forming wetlands, and particularly floating fens forming the initial stages of these ecosystems, are globally declining due to excavation, dehydration and eutrophication. Restoration of these valuable ecosystems typically involves re‐establishment of early‐successional open‐water stages with oligotrophic conditions that are characteristic for these systems. However, restoration success is notoriously limited. We experimentally tested how (1) increasing functional diversity of introduced species and (2) nutrient availability would possibly stimulate resotration success, using 36 artificial outdoor ponds for 2 years. We found that restoration of floating fen communities (1) can be stimulated by introducing a high functional diversity of plant species, including fast‐growing clonal species, clonal stress‐tolerators and interstitials, which facilitate each other, (2) is dependent on the presence of clonal stress‐tolerators such as Calla palustris, Comarum palustre and Menyanthes trifoliata for expansion onto the open water, (3) can start under a wide range of water nutrient levels, including eutrophic conditions.

Zhang, P., B.M. Grutters, C.H.A. van Leeuwen, J. Xu, A Petruzzella, R.F. van den Berg, E.S. Bakker (2018)
Effects of rising temperature on the growth, stoichiometry and palatability of aquatic plants
Frontiers in Plant Science pdf
Content: We experimentally investigated how rising water temperatures - as an important component of global changes - may affect plant chemical traits and plant palatability in freshwater ecosystems.
If warming water would increase plant palatability to herbivores, this could subsequently increase top-down control of aquatic vegetation in the future. We found that warming generally stimulated the growth of the investigated aquatic plant species, but also that any changes in plant traits and palatability were highly species-specific. This implies that species identity is an important factor to take into account when predicting how global change may affect aquatic vegetation in the future.

Zhang, P, R.F. van den Berg, C.H.A. van Leeuwen, B.A. Blonk, E.S. Bakker, (2018)
Aquatic omnivores shift their trophic position towards increased plant consumption as plant stoichiometry becomes more similar to their body stoichiometry

PLoS ONE  pdf
Content: Eutrophication in aquatic ecosystems increases plant nutrient concentrations. We experimentally showed that aquatic omivores shift to a more plant-based diet in more eutrophied aquatic systems, because plants become relatively more attractive food sources. Because most aquatic consumers are omnivores, increased nutrient loadings into aquatic systems may increase top-down control on aquatic plants.

C.H.A. van Leeuwen (2018)
Internal and external dispersal of plants by animals: an aquatic perspective on alien interference
Frontiers in Plant Sciences 9:153 pdf
Content: Many alien plants use animal vectors for dispersal of their diaspores (zoochory). If these alien plants interact with native disperser animals, this can interfere with animal-mediated dispersal of native diaspores. Interference by alien species is known for frugivorous animals dispersing fruits of terrestrial plants by ingestion, transport and egestion (endozoochory). However, little attention has been paid to possible interference of alien plants with dispersal of diaspores via external attachment (ectozoochory, epizoochory or exozoochory), interference in aquatic ecosystems, or positive effects of alien species on dispersal of native plants. In this literature study I address the following hypotheses: (1) alien plants may interfere with both internal and external animal-mediated dispersal of native diaspores; (2) interference also occurs in aquatic ecosystems; (3) interference of alien plants can have both negative and positive effects on native plants. Testing these hypotheses using the literature reveals many possibilities for future research and emphasizes the importance of understanding the effects of alien plant species on animal-mediated dispersal in the light of conservation.
Van Leeuwen, C.H.A. and S.E. Jamieson (2018)
Strong pair bonds and high site fidelity in a subarctic-breeding migratory shorebird
The Wilson Journal of Ornithology 130(1):140-151 pdf 
Content: We investigated mate and site fidelity of the migratory shorebird Pacific Dunlin (Calidris alpina pacifica) breeding at the subarctic Yukon-Kuskokwim Delta, Alaska, USA. We found subarctic-breeding Dunlin to strongly prefer previous breeding locations and previous mates when these were available in consecutive breeding attempts. However, if sites or mates were unavailable for breeding, their behavior prioritized early nest initiation and fast renesting over mate and site fidelity. This study illustrates the high importance of timing for migratory birds nesting in the short subarctic summer.
Petruzzella, A., Manschot, J., Van Leeuwen, C.H.A., Grutters, B.M. and E.S. Bakker (2018)
Mechanisms of invasion resistance of aquatic plant communities
Frontiers in Plant Sciences 9:134 pdf
Content: A greenhouse experiment with aquatic plants revealed that the presence of native vegetation decreased the establishment success of an alien aquatic plant species. The strength of this biotic resistance increased with increasing species richness of the native community. Native biomass of mixed communities overyielded, which further lowered the establishment success of the invader. Strongest biotic resistance was caused by the two native plant species that were functionally most similar to the invader.
Van Leeuwen, C.H.A., K. Dalen, J. Museth, C. Junge and L.A. Vøllestad (2018)
Habitat fragmentation has interactive effects on the population genetic diversity and individual behaviour of a freshwater salmonid fish
River Research and Applications 34(1):60-68 pdf
Content: We investigated how habitat fragmentation interacted with population genetic diversity and individual behaviour of European grayling (Thymallus thymallus) in a large river systems. Combining genotyping and radio-tracking of adult fish indicated that (1) upstream sub-populations in fragmented rivers show less genetic variation, which makes it less likely for them to adapt to environmental changes; (2) fish with distinct genotypes in the same habitat can differ in their behaviour; (3) spawning site selection (natal philopatry) can differ between fish of the same species living in different habitats (river or lake-tributary systems). Habitat loss and river fragmentation may differently affect individual fish of the same species, if they live in different types or sections of habitat.
Van Leeuwen, C.H.A., Á. Lovas-Kiss, M. Ovegård and A.J. Green (2017)
Great cormorants reveal overlooked secondary dispersal of plants and invertebrates by piscivorous waterbirds
Biology Letters 13(10): 20170406 pdf
Content: Birds and fishes frequently disperse plants by ingesting plant seeds, then moving before egesting them, so helping to maintain plant biodiversity. Since birds move more than fish, Darwin first proposed that fish-eating birds may be important for dispersing seeds that were inside the fish when they swallowed them. We studied this idea in great cormorants, widespread fish-eating birds that egest indigestible items in pellets. We found these pellets to contain a wide diversity of aquatic and terrestrial plant seeds, plus aquatic invertebrates. The species that were dispersed depended on what fish species were eaten. This study is the first to quantify the role of fish-eating birds in dispersing plants and invertebrates.
Van Leeuwen, C.H.A., T. Dokk, T.O. Haugen, P.M. Kiffney and J. Museth (2017)
Small larvae in large rivers: observations on downstream movement of European grayling Thymallus thymallus during early life stages
Journal of Fish Biology 90(6): 2412-2424 pdf
Content: We investigated behaviour of early life stages of the salmonid European grayling Thymallus thymallus in large river systems by trapping of larvae moving downstream and electrofishing surveys. Larvae moved downstream predominantly during night, close to the substrate, and few young-of-the-year still resided close to the spawning areas in autumn. These observations advocate that there may be a deliberate, active component to downstream movement of European grayling during early life stages. This implies that human alterations of flow regimes and the construction of reservoirs for hydropower interfere with active movement behaviour of fish during critical early life stages. 
Gilioli G., Schrader G., Carlsson N., van Donk E., Van Leeuwen C.H.A., Martín P.R., Pasquali S., Vila M. and S. Vos (2017)
Environmental risk assessment for invasive alien species: A case study of apple snails afffecting ecosystem services in Europe 
Environmental Impact Assessment Review 65: 1-11 pdf
Content: We present a case study that illustrates how quantitative estimates of environmental risk assessment impacts can be used by decision makers and managers that have to balance the costs of control efforts against environmental and economic impacts of invasive species. The invasive apple snails Pomacea canaliculata and Pomacea maculata are used to demonstrate the application of an innovative procedure ssessing the potential impact of these species on shallow freshwater ecosystems with aquatic macrophytes in Europe. 
Van Leeuwen, C.H.A., J. Museth, O.T. Sandlund, T. Qvenild and L.A. Vøllestad. (2016)
Mismatch between fishway operation and timing of fish movements: a risk for cascading effects in partial migration systems 

Ecology and Evolution 6(8):2414-2425 pdf

Content: Fishways with restricted seasonal operation times were found to affect upstream spawning migrations of both spring and autumn spawning salmonid fish. We discuss possible effects of late opening and early closing of fish passages in a theoretical framework, in which we propose that movement restrictions of migratory individuals in partially migratory populations can also indirectly affect conditions for resident fish in the same river system.

Van Leeuwen, C.H.A., R. BeukeboomB.A. Nolet, E.S. Bakker and B.J.A. Pollux (2016)
Locomotion during digestion changes current estimates of seed dispersal kernels by fish
Functional Ecology 30:215-225 pdf
Content: Physical activity during animal locomotion affects how their digestive system processes food, which has implications for their role as seed dispersers. We found that physically active fish retained ingested seeds longer than inactive fish, implying that modelling dispersal kernels using parameters from inactive fish underestimates potential dispersal distances of plants by endozoochory in aquatic systems.  
Noback, M.L., E. Samo, C.H.A. van Leeuwen, N. Lynnerup, and K. Harvati (2016)
Paranasal sinuses: A problematic proxy for climate adaptation in Neanderthals
Journal of Human Evolution 97: 176-179 pdf
Content: We contribute to an online discussion on whether paranasal sinuse volume can be used as a proxy for climate adaptation in humans and Neanderthals. According to our data past inferences on this relation are problematic.
Kleyheeg, E. and C.H.A. van Leeuwen (2015)
Regurgitation by waterfowl: an overlooked mechanism for long-distance dispersal of wetland plant seeds
Aquatic Botany 127:1-5 pdf
Content: Seed regurgitation by waterbirds is an overlooked dispersal mechanism in wetlands. We found that regurgitation by waterbids can follow overfeeding or the ingestion of large indigestible seeds. As plant seeds are more likely to survive regurgitation than entire gut passage, regurgitation may make a suitable dispersal pathway for seeds that are unable to resist digestion during endozoochory.  
Garcia-Álvarez, A., C.H.A. van Leeuwen, C.J. Luque, A. Hussner, A. Vélez-Martin, A. Pérez-Vázquez, A.J. Green, E.M. Castellanos (2015)

Internal transport of alien and native plants by geese and ducks - an experimental study
Freshwater Biology 60(7): 1316-1329 pdf
Content: Experiments on the transport of plant seeds by waterbirds revealed that: i) smaller ducks differ from larger geese in their role as dispersal vectors ii) invasive water primrose Ludwigia grandiflora has a greater dispersal potential than invasive cordgrass Spartina densiflora, which is consistent with its faster range expansion across Europe, and iii) maximum retention times of wetland seeds have been underestimated in previous experimental studies that lasted only 1–2 days, as intact seeds were retrieved from faeces for up to 4 days after ingestion. More attention should be paid to the role of waterbirds as vectors of alien plants and to the role of migratory geese as vectors of plants in general.  

Kleyheeg, E., C.H.A. van Leeuwen, M.A. Morison, B.A. Nolet and M.B. Soons (2014)
Bird-mediated seed dispersal: reduced digestive efficiency in active birds modulates dispersal capacity of plant seeds
Oikos 124(7): 899-907 pdf
Content: Seed retrieval patterns of nine wetland plants were found to differ between resting and physically active mallards (Anas platyrhynchos). Physical activity increased the retrieval of intact seeds and modestly accelerated gut passage of seeds, however, in a plant species-specific way. Interactions between the digestion resilience of a particular seed species and the physical activity of an actively moving vector organism should be taken into account when constructing zoochoric dispersal kernels.
Van Leeuwen, C.H.A., J.M. Sarneel, J. van Paassen, W. Rip and E.S. Bakker (2014) 

Hydrology, shore morphology and species traits affect seed dispersal, germination and community assembly in riparian plant communities.

Journal of Ecology 102: 998-1007 pdf

Content: Seed dispersal and germination of plants on the shores of wetlands is influenced by water level fluctuations, shore morphology and seed characteristics. Active water level management and shore restoration can contribute to the creation of rich riparian plant communities. 

Van Leeuwen, C.H.A., N. Huig, G. van der Velde, T.A. van Alen, C.A.M. Wagemaker, C.D.H. Sherman, M. Klaassen and J. Figuerola (2013)

How did this snail get here? Multiple dispersal vectors inferred for an aquatic invasive species.

Freshwater Biology 58(1): 88-99 pdf

Content: Microsatellite analyses reveal how invasive aquatic snails (Physa acuta) can colonize isolated freshwater ponds in Doñana National Park (Spain) by using a multitude of passive dispersal vectors: water currents, waterbirds and large mammals.

Van Leeuwen, C.H.A., G. van der Velde, J.M. van Groenendael and M. Klaassen (2012)

Gut travellers: internal dispersal of aquatic organisms by waterfowl.

Journal of Biogeography 39(11): 2031-2040 pdf    supp1   supp2   supp3

Content: This is the first quantitative meta-analysis on internal transport of aquatic invertebrates and wetland plant seeds by waterbirds. Analysis of over 80 publications (which can be found in supplementary 1) indicates the state of the art on bird-mediated dispersal, and is used to present the first calculations on the quantitative and qualitative importance of endozoochory as a long distance dispersal mechanism.

Van Leeuwen, C.H.A. and G. van der Velde (2012)

Prerequisites for flying snails: external transport potential of aquatic snails by waterbirds.

Freshwater Science 31(3): 963-972 pdf

Content: This study experimentally addresses dispersal of snails on the outside of birds, known as ectozoochory. A large selection of aquatic snail species is highly tolerant to desiccation, will attach readily to the exterior of waterbirds, and can stay attached for over 8 hours in drying mud. Aquatic snails appear to have all the necessary prerequisites for successful zoochory by birds or other large animals.

Van Leeuwen, C.H.A., M.L. Tollenaar, and M. Klaassen (2012)

Vector activity and propagule size affect dispersal potential by vertebrates.

Oecologia 170(1): 101-109 pdf

Content: In this paper we describe how physical activity of mallards (Anas platyrhynchos), in the form of swimming, alters their digestive physiology. This has implications for the construction of seed dispersal kernels by zoochory, which have to date always been based on seed release patterns obtained from experiments with resting animals. We show for the first time that modelling dispersal kernels to predict seed dispersal distances by zoochory should incorporate potential digestive changes induced by the physical movement of animal vectors.

Van Leeuwen, C.H.A., G. Van der Velde, B. Van Lith, and M. Klaassen (2012) 

Experimental quantification of long distance dispersal potential of aquatic snails in the gut of migratory birds.

PLoS ONE 7:e32292 pdf

Content: This publication shows how aquatic snails can survive digestion of waterbirds. In a feeding experiment, snails were retrieved over five hours after ingestion, indicating for the first time that long distance endozoochory of aquatic snails is possible.

Dietz M.W., B. Spaans, A. Dekinga, M. Klaassen, H. Korthals, C.H.A. van Leeuwen, and T. Piersma (2010) 

Do red knots (Calidris canutus islandica) routinely skip Iceland during southward migration?

Condor 112(1): 48-55 pdf

Content: Stable isotope analyses of red knots (Calidris canutus islandica) reveal that these birds do not always use all available stopover sites on migration, but that direct migration from Greenland to Western-Europe occurs without a stopover in Iceland, even for juveniles.

Klaassen, R.H.G., B.A. Nolet, and C.H.A. van Leeuwen (2007)

Prior knowledge about spatial pattern affects patch assessment rather than movement between patches in tactile-feeding mallard.

Journal of Animal Ecology 76(1): 20-29 pdf

Content: This experiment with mallards (Anas platyrhynchos) reveals that birds searching for cryptic food items can make use spatial patterns to optimize their food intake over time.