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Pollination processes and the Allee effect in highly fragmented populations: consequences for the mating system in urban environments
Author(s) -
Cheptou PierreOlivier,
Avendaño V Lyz G.
Publication year - 2006
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2006.01880.x
Subject(s) - selfing , pollinator , pollination , biology , allee effect , mating system , outcrossing , open pollination , ecology , botany , mating , population , pollen , demography , sociology
Summary• The urban environment was used to study the plant reproductive system in small fragmented populations as well as the potential adaptations of plants to urban conditions. We examined the effect of density on the pollination process and on reproduction in urban populations of the allogamous species Crepis sancta . The habitat is composed of small uncultivated square patches ( c . 2 m 2 ) regularly spaced along the pavement in streets of the city of Montpellier, France. • Pollinator behaviour (the presence of pollinators, the number of flowers visited and the duration of each visit) and seed set as a function of the number of plants in patches and selfing rates, determined using progeny array analysis, were studied. The propensity for the urban populations to produce seeds by self‐fertilization in insect‐proof glasshouse was also analysed. • We found strong evidence of reduced pollinator activities at low densities, resulting in reduced pollination and a reduction in seed set from 80 to 20% of ovules fertilized (the Allee effect). • Progeny array analysis revealed a slight increase (marginally significant) in selfing rates in urban populations compared with large populations. In spite of lower pollinator activity, urban populations did not show a greater ability to self‐fertilize compared with rural populations from the nearby countryside.