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Litter inputs and plant interactions affect nectar sugar content
Author(s) -
Baude Mathilde,
Leloup Julie,
Suchail Séverine,
Allard Béatrice,
Benest Danielle,
Mériguet Jacques,
Nunan Naoise,
Dajoz Isabelle,
Raynaud Xavier
Publication year - 2011
Publication title -
journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.452
H-Index - 181
eISSN - 1365-2745
pISSN - 0022-0477
DOI - 10.1111/j.1365-2745.2011.01793.x
Subject(s) - nectar , biology , pollinator , plant community , agronomy , litter , competition (biology) , ecology , species richness , pollination , pollen
Summary 1. Declines in availability of plant resources to pollinators are a major cause of pollinator loss. The management of plant communities to enhance floral resources is often proposed as a way to sustain pollinator populations. Nectar, the main energetic resource for pollinators, plays a central role in behaviour and composition of pollinator communities. Abiotic and biotic factors are known to influence nectar traits at both the species and community levels, but the impact of plant community composition itself has never been investigated. 2. Below‐ground interactions in plant communities can induce changes in plant development through (i) plant‐derived litter amendment of the soil and (ii) competition for soil resources between plants. We tested how plant below‐ground interactions affect above‐ground nectar traits involved in plant attractiveness to pollinators. 3. A short‐term pot experiment was carried out with three temperate grassland species Mimulus guttatus, Lamium amplexicaule , and Medicago sativa , showing distinct litter stoichiometry and competitive abilities for soil resources. Litter amendment (none, mono and tri‐specific litter) and plant interaction treatments (monocultures, two‐ and three‐species mixtures) were crossed in a factorial design. 4. Litter amendment to the soil led to an increase in total nectar sugar content in L. amplexicaule plants but not in the two other species. We also found that the presence of M. guttatus, a competitive species, reduced the total nectar sugar content in L. amplexicaule through a concomitant decrease in nectar volume per flower and in floral display size, but not in other species. Species‐specific responses of nectar traits to variation in soil nitrogen availability were thus observed, suggesting consequences for plant species and community attractiveness to pollinators. However, we did not find evidence that the legume M. sativa affected nectar traits of any neighbouring plants. 5. Synthesis. Our results demonstrate that litter inputs and competition between plants for soil resources can alter nectar traits linked to plant attractiveness to pollinators. This supports the idea that below‐ground plant–plant interactions for soil resources can influence above‐ground plant–plant interactions for pollination services. This offers promising perspectives in studying the role of below‐ground–above‐ground interactions on higher trophic levels.