Mitigating a decline in wild plant pollination
The need for food is steadily increasing, and the expansion of arable land is paralleled by a decline in habitat for wild organisms. How to feed the human population without impoverishing the biodiversity is a challenge, a challenge that increases with a growing population.
Agricultural intensification has been particularly harmful to flowering plants, which have suffered from eutrophication, herbicides and loss of meadows and traditional pastures. Because nine out of ten flowering plant species are pollinated by animals, declining populations of pollinating insects could pose an additional threat. Insect-pollinated plants use insects to transfer pollen between flowers. When pollen ends up at a stigma it can germinate, and fruits and seeds are produced. Without pollinating insects, many flowering plants would therefore set fewer or no seeds, there would be no bilberries in the forests, and we would suffer from reduced yields in insect-pollinated crops such as apples, strawberries and tomatoes.
I work with assessing how different components of modern agriculture affect wild pollinators and pollination. My main focus is wild plant pollination and biodiversity conservation, but in a few studies I have also assessed how insect-pollinated crops are affected by factors expected to benefit or harm wild pollinators.
Pollination, Wild plants, Biodiversity, Pollinators, Ecosystem services, Agricultural landscapes
Some studies I’m involved in
Oilseed rape is an increasingly important flowering crop, with nectar and pollen-rich flowers that attract a wide range of pollinating insects. While oilseed rape benefits some bee species, the higher density of pollinators around the fields seems to increase competition for food after the flowering, which according to previous studies appears to be particularly harmful to long-tongued bumble bees. Through the project ‘Status and Trends of European Pollinators’ (STEP) I am assessing if this possible change in pollinator community composition and abundance affects wild plant pollination in the surrounding landscape.
Neonicotinoids are a rather new group of pesticides that have conquered the market partly thanks you their systemic way of working. Being systemic, they get absorbed by the crop and spread to all its tissues from where they give the crop a long-lasting protection against pest insects. In a replicated landscape study we assessed the impacts of the neonicotinoid clothianidin on wild bees and honey bees. Clothianidin had clearly negative effects on wild bee densities in the fields and on the reproduction of the two assessed wild bee species: buff-tailed bumble bee (Bombus terrestris) and red mason bee (Osmia bicornis). However, no effect was found on honey bees. Link to the article.
Small-scale studies and experiments with potted plants show a potentially high value of insect-pollination in oilseed rape. In a replicated landscape study, Sandra Lindström and I have assessed if honey bees can be used to increase oilseed rape yields at a field scale, and which impact this may have on pollinators and wild plant pollination in the surrounding landscape, and also if the potential effect depends on landscape complexity.
Link to project webpage.
Before starting a PhD in Environmental Science I studied Biology at Lund University. During the studies I got interested in species distributions and interdependencies, and decided to study Biogeography. This brought me to the University of Valencia in Spain, where I later wrote my master thesis: “Surprisingly Low Genetic Diversity in Psilotum nudum and Possible Paraphyly in Psilotum Species”. After presenting the thesis I finished my degree by doing a minor field study in collaboration with Vi Agroforestry in Tanzania.
Henrik Smith, Centre for Environmental and Climate Research & Department of Biology, Lund University
Maj Rundlöf, Department of Biology, Lund University
Riccardo Bommarco, Department of Ecology, Swedish University of Agricultural Sciences
Retrieved from Lund University's publications database
- Assessing the risk of stigma clogging in strawberry flowers due to pollinator sharing with oilseed rape
- Pollinators and Insect Pollination in Changing Agricultural Landscapes
- The relation between oilseed rape and pollination of later flowering plants varies across plant species and landscape contexts
- Competition between managed honeybees and wild bumblebees depends on landscape context
- Experimental evidence that honeybees depress wild insect densities in a flowering crop
- Large-scale pollination experiment demonstrates the importance of insect pollination in winter oilseed rape.
- Non-bee insects are important contributors to global crop pollination.
- Sparing land for biodiversity at multiple spatial scales