title: Subtle Gardeners: Inland Predators Enrich Local Topsoils and Enhance Plant Growth.
abstract: Inland vertebrate predators could enrich of nutrients the local top soils in the area surrounding their nests and dens by depositing faeces, urine, and prey remains and, thus, alter the dynamics of plant populations. Surprisingly, and in contrast with convincing evidence from coastal habitats, whether and how this phenomenon occurs in inland habitats is largely uncertain even though these habitats represent a major fraction of the earth's surface. We investigated during two consecutive breeding seasons the potential enrichment of the top-soils associated with inland ground-nesting eagle owls Bubo bubo, as well as its possible consequences in the growth of two common annual grasses in southern Spain. Top-soils associated with owl nests differed strongly and significantly from control top-soils in chemical parameters, mainly fertility-related properties. Specifically, levels of available phosphorus, total nitrogen, organic matter, and available potassium were 49.1, 5.6, 3.1, and 2.7 times higher, respectively, in top-soils associated with owl nests as compared to control top-soils. Germination experiments in chambers indicated that nutrient enrichment by nesting owls enhanced seedling growth in both annual grasses (Phalaris canariensis and Avena sativa), with seedling size being 1.4-1.3 times higher in owl nest top-soils than in control top-soils. Our experimental study revealed that pervasive inland, predatory birds can profoundly enrich the topsoil around their nests and, thus, potentially enhance local vegetation growth. Because diverse inland vertebrate predators are widespread in most habitats they have a strong potential to enhance spatial heterogeneity, impinge on plant communities, and exert an overlooked effect on primary productivity worldwide.
authors.affiliation: Centre for Applied Ecology "Prof. Baeta Neves"/InBIO, Institute Superior of Agronomy, University of Lisbon, Tapada da Ajuda, Lisboa, Portugal; Department of Conservation Biology, Estación Biológica de Doñana, C.S.I.C., c/ Americo Vespucio s/n, Seville, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Fedriani
authors.affiliation: Department of Conservation Biology, Estación Biológica de Doñana, C.S.I.C., c/ Americo Vespucio s/n, Seville, Spain.
authors.forename: Pedro José
authors.initials: PJ
authors.lastname: Garrote
authors.affiliation: Metapopulation Research Group, Department of Biosciences, University of Helsinki, Helsinki, Finland; Research Unit of Biodiversity (UMIB, UO-CSIC-PA), Oviedo University - Campus Mieres, Mieres, Spain.
authors.forename: María del Mar
authors.initials: Mdel M
authors.lastname: Delgado
authors.affiliation: Department of Conservation Biology, Estación Biológica de Doñana, C.S.I.C., c/ Americo Vespucio s/n, Seville, Spain; Metapopulation Research Group, Department of Biosciences, University of Helsinki, Helsinki, Finland; Research Unit of Biodiversity (UMIB, UO-CSIC-PA), Oviedo University - Campus Mieres, Mieres, Spain.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Penteriani
mesh_terms: D000818:Animals; D017753:Ecosystem; D005243:Feces; D009425:Nesting Behavior / Q000502:physiology*; D063245:Plant Development; D011157:Population Dynamics; D011235:Predatory Behavior / Q000502:physiology; D012621:Seasons; D036226:Seedlings / Q000254:growth & development; D012987:Soil / Q000737:chemistry*; D020305:Strigiformes / Q000502:physiology*
chemical_list: D012987:Soil