Avian Ecology and Evolution group

Prof. dr. Luc Lens
Terrestrial Ecology Unit
Department of Biology
Ghent University
K.L. Ledeganckstraat 35
9000 Gent Belgium

Phone: +32 (0)9 264 52 54
E-mail: luc.lens@ugent.be

Research

Individual-based ecology predicts how populations are affected by environmental change through the study of individual performance and responses. Such approach requires a thorough understanding of individual behaviour, physiology, endocrinology, and ecology. Given that these properties are exceptionally well known in many bird species, we use this taxon to study proximate and ultimate effects of environmental change on genotypic and phenotypic variation in free-living populations. To unravel generic patterns and processes, we study individuals of sedentary and migratory species from temperate and tropical communities – which we (try to) follow year-round in order to assess interactions between subsequent life-history stages. Topics of special interest are reproductive and dispersal/migration strategies, paternal and maternal investment strategies, population genetics and genomics, host-parasite interactions and nutritional ecology.

Our field sites are both ecologically diverse and globally scattered, ranging from coastal and urban areas in Flanders to Mediterranean highlands in Spain and tropical rainforests in eastern Africa and Costa Rica. Our hallmarks are scientific excellence and technological innovation, which we try to achieve through multidisciplinary collaboration with experts in spatial ecology, behavioural endocrinology and physiology, genomics, and nutritional ecology, and by involving conservation NGOs and citizen-science participants.


Major topics

Urban ecology and evolution

As natural habitats are being lost at an accelerating rate and the world steadily becomes more urbanized, biologists are increasingly interested in possible urbanization effects on wildlife. Birds are particularly good model systems since their life history, behaviour, and physiology are believed to be sensitive to urban-related stressors such as new pathogens and predators, light and sound pollution, and unnatural food regimes. Moreover, in highly urbanized areas such as Flanders, it is possible to compare the evolutionary ecology of urban populations with that of suburban and rural counterparts in spatially-paired and repeated designs. Within the framework of an Inter-university Attraction Poles program on spatial and environmental determinants of eco-evolutionary dynamics (Belgian Science Policy Office, 2012-2017), we study the nutritional and microbial ecology, neutral and functional (MHC) genetic variation, and parasite-host interactions in spatially-structured house sparrow populations along urban gradients in Flanders.

Involved researchers: Prof. Dr. Luc Lens

Selected publications:

Vangestel C. & Lens L. (2011). Does fluctuating asymmetry constitute a sensitive biomarker of nutritional stress in house sparrows (Passer domesticus)? Ecological Indicators 11: 389–394.

Vangestel C., Mergeay J., Dawson D.A., Vandomme V. & Lens L. (2011). Developmental stability covaries with genome-wide and single-locus heterozygosity in house sparrows. PLoS ONE 6: e21569.

Vangestel C., Mergeay J., Dawson D.A., Vandomme V. & Lens L. (2011). Spatial heterogeneity in genetic relatedness among house sparrows along an urban-rural gradient as revealed by individual-based analysis. Molecular Ecology 20: 4643–4653.

Vangestel C., Braeckman B.P., Matheve H. & Lens L. (2010). Constraints on home range behaviour affect nutritional condition in urban House sparrows (Passer domesticus). Biological Journal of Linnean Society 101: 41–50.


Life-history strategies in migratory species

Organisms differentially invest in growth, reproduction and survival throughout their lifetime, and life-history theory attempts to understand why individuals and populations vary in life-history strategies. Because of multiple and complex interactions and trade-offs among different life-history stages, understanding variation in life-history strategies hinges on the feasibility to track individuals throughout their annual cycle. In migratory species, however, breeding and non-breeding stages are not only separated in time but may also take place at spatially distant locations. This inevitably complicates the study of year-round LH strategies. Within the framework of a Research Foundation Flanders program on trans-generational effects of ageing and food acquisition strategies in migratory lesser black-backed gulls (FWO, 2014-2017), we study how spatial behaviour in wintering sites affects sex and age related variation in timing of arrival in Flemish breeding colonies and how this in turn relates to reproductive strategies and performance. We investigate how pre-hatching environmental variation and post-hatching parental feeding strategies affect the ecotoxicology, stress- and nutritional physiology, and food acquisition strategies of developing offspring.

Involved researchers: Prof. Dr. Luc Lens

Selected publications:

Bosman D.S., Vercruijsse H.J.P., Stienen E.W.M., Vincx M. & Lens L. (2013). Age of first breeding interacts with pre- and post-recruitment experience in shaping breeding phenology in a long-lived gull. PLoS ONE 8: e82093.

Bosman D.S., Vercruijsse H.J.P., Stienen E.W.M., Vincx M., De Neve L. & Lens L. (2013). Effects of body size on sex-related migration vary between two closely related gull species with similar size dimorphism. Ibis 154: 52-60.


Tropical ecology and evolution

Unlike in temperate zones, year-round food availability in tropical areas means that most (insectivorous) bird species are resident and that breeding seasons are typically extended (four to eight months) and mainly timed to coincide with fruit or insect abundance or reduced predation pressure, rather than with climatic variation per se. This sharply contrasts with the temperate zone where climate is a major constraint that forces birds to breed quickly. Such tropical-temperate zone differences set the stage for major differences in social behaviour and life-history strategies, and hence, in appropriate conservation strategies to safeguard avian biodiversity.

Within the framework of a Research Foundation Flanders program on effects of Afrotropical rainforest fragmentation on cooperative breeding strategies (FWO, 2013-2016) and various north-south biodiversity programs with universities and NGOs, we study how loss, degradation and fragmentation of tropical rainforest shape reproductive, dispersal, settlement and territorial strategies, patterns of functional diversity and landscape genetics in forest-dependent bird species.

Two recently-started tropical studies deal with conservation-related topics in great apes (Cameroon) and macaws (Costa Rica).

Involved researchers: Prof. Dr. Luc Lens – Drs. Laurence CousseauDrs. Walesa Edho Prabowo

Selected publications:

Aben J., Strubbe D., Adriaensen F., Palmer S.C.F., Travis J.M.J., Lens L. & Matthysen E. (2014). Simple individual-based models effectively represent Afrotropical forest bird movement in complex landscapes: implications for improved management recommendations. Journal of Applied Ecology 51: 693-702.

Habel J.C., Mulwa R.K., Gassert F., Rödder D., Ulrich W., Borghesio L., Husemann M. & Lens L. (2014). Population signatures of large-scale, long-term disjunction and small-scale, short-term habitat fragmentation in an Afromontane forest bird. Heredity 114: 828-836.

Vangestel C., Callens T., Vandomme V. & Lens L. (2013). Sex-biased dispersal at different geographical scales in a cooperative breeder from fragmented rainforest. PLoS ONE 8: e71624.

Lehouck V., Spanhove T., Vangestel C., Cordeiro N. J. & Lens L. (2009). Does landscape structure affect resource tracking by avian frugivores in a fragmented Afrotropical forest? Ecography 32: 1-11.

Lens L., Van Dongen S., Norris K., Githiru M. & Matthysen E. (2002). Avian persistence in fragmented rainforest. Science 298: 1236-1238.

Lens L. & Van Dongen S. (2000). Fluctuating and directional asymmetry in natural bird populations exposed to different levels of habitat disturbance, as revealed by mixture analysis. Ecology Letters 3: 516-522.

Lens L., Van Dongen S., Wilder C.M., Brooks T.M. & Matthysen E. (1999). Fluctuating asymmetry increases with habitat disturbance in seven bird species of a fragmented afrotropical forest. Proceedings of the Royal Society B-Biological Sciences 266: 1241-1246.


Functional diversity, resilience and ecosystem services

Avian population reductions and extinctions may disrupt ecosystem processes and services such as pollination, seed dispersal and pest control. At species level, these services are thought to be function of avian fitness and health, i.e. through variation in exploration and activity levels, space use, food intake rates, immune-competence, or exposure to pathogens. Highly specialized and evolutionarily unique species are more likely to go (locally) extinct and the probability of other species taking their place and ecological role is uncertain. This may have important consequences for the resilience of an ecosystem. Among the bird functional groups that are expected to have more extinctions than average are nectarivorous pollinators, frugivorous seed dispersers, and understory insectivores.

We have been investigating causes and consequences of variation in seed dispersal by tropical frugivorous birds in our long-term study site in Kenya, and are continuing to do so in fragmented Ethiopian coffee forests. Sponsored by a Special Research Fund from Ghent University (GOA, 2014-2019), we will further study how tree diversity and landscape fragmentation synergistically affect the fitness, health and predatory performance of temperate zone insectivores, and how this feeds back to lower trophic levels.

Involved researchers: Prof. Dr. Luc Lens

Selected publications:

Lehouck V., Spanhove T. & Lens L. (2011). Avian fruit ingestion differentially facilitates seed germination of four fleshy-fruited plant species of an Afrotropical forest. Plant Ecology and Evolution 144: 96-100.

Lehouck V. Spanhove T., Gonsamo A., Cordeiro N. & Lens L. (2009). Spatial and temporal effects on recruitment of an Afromontane forest tree in a threatened fragmented ecosystem. Biological Conservation 142: 518 -528.

Lehouck V., Spanhove T., Colson L., Adringa-Davis A., Cordeiro N.J. & Lens L. (2009). Habitat disturbance reduces seed dispersal of a forest interior tree in a fragmented African cloud forest. Oikos 118: 1023-1034.

Lehouck V., Spanhove T., Demeter S., Groot N.E., & Lens L. (2009). Complementary seed dispersal by three avian frugivores in a fragmented Afromontane forest. Journal of Vegetation Science 20: 1110-1120.

Lehouck V., Spanhove T., Vangestel C., Cordeiro N. J. & Lens L. (2009). Does landscape structure affect resource tracking by avian frugivores in a fragmented Afrotropical forest? Ecography 32: 1-11.


Coevolutionary interactions between parasites and their hosts

Infection with parasites and pathogens is costly for hosts, causing loss of nutritional resources, reproductive potential, tissue integrity and even life. In response, animals have evolved behavioural and immunological strategies to avoid infestation by parasites, which, in turn, selects for counter-adaptations in parasites, giving rise to coevolutionary arms races. However, since defences and counter-defences entail costs, individuals should benefit from balancing investment in different strategies. Here we are interested in how maternal investment strategies can be adaptive to prepare offspring to anticipated pathogen environments.

A classic example of host-parasite interactions are those between brood parasites and their hosts. Interspecific avian brood parasites lay their eggs in the nests of one or more host species, which incubate and care for the unrelated parasitic offspring. Hosts thereby suffer severe reductions in reproductive success and brood parasites entirely depend on their host species for successful reproduction. As such, interactions between brood parasites and their hosts have proved to be very fruitful in demonstrating evolution in action. Within the framework of an ongoing coevolutionary arms race between a non-evictor brood parasite, the great spotted cuckoo and its main host in Europe, the magpie, we study reproductive strategies and coevolutionary interactions in brood parasite and host during the whole reproductive cycle (pre-laying, egg-laying, nestling and post-fledging phase).

Involved researchers: Prof. Dr. Luc Lens

Selected publications:

Soler J.J., De Neve L., Martín-Gálvez D., Molina-Morales M., Pérez-Contreras T. & Ruiz-Rodríguez M. (2014). Do climatic conditions affect host and parasite phenotypes differently? A case study of magpies and great spotted cuckoos. Oecologia 174: 327–338.

Soler M. & De Neve L. (2013). Brood mate eviction or brood mate acceptance by brood parasitic nestlings? An experimental study with the non-evictor great spotted cuckoo and its magpie host. Behavioral Ecology and Sociobiology 67: 601-607.

De Coster G., De Neve L., Verhulst S. & Lens L. (2012). Maternal effects reduce oxidative stress in female nestlings under high parasite load. Journal of Avian Biology 43: 177-185.

De Neve L., Ibañez-Álamo J.D., Roldán M., Rodríguez J., Trouve C., Chastel O. & Soler M. (2012). Corticosterone levels in host and parasite nestlings: Is brood parasitism a hormonal stressor? Hormones and Behavior 61: 590-597.

Martín-Gálvez D., De Neve L., Pérez-Contreras T., Soler M., Martínez J.G. & Soler J.J. (2012). Manipulation of hunger levels affects great spotted cuckoo and magpie host nestlings differently. Journal of Avian Biology 43: 531-540.

Soler M., De Neve L., Roldan M., Macias-Sanchez E. & Martin-Galvez D. (2012). Do great spotted cuckoo nestlings beg dishonestly? Animal Behaviour 83: 163-169.

De Coster G., De Neve L., Martín-Gálvez D., Therry L. & Lens L. (2010). Variation in innate immunity in relation to ectoparasite load, age and season: a field experiment in great tits (Parus major). Journal of Experimental Biology 213: 3012-3018.


Publication list (UGent affiliations only)