DOI: 10.5061/dryad.3m342
title: Data from: Spatial heterogeneity of a parasitic plant drives the seed-dispersal pattern of a zoochorous plant community in a generalist dispersal system

description: Biota plays a central role as sources of spatial heterogeneity, having
 great potential to define ecological processes and patterns in the
 landscape. Mistletoes are fleshy-fruited parasitic plants that dwell in
 forest canopies showing a strong aggregated spatial distribution.
 Parasitized trees potentially concentrate frugivore activity on their
 canopy, where birds find food, places to perch and protection against
 predators. Thus, seed-deposition patterns generated from the canopy are
 expected to reflect the heterogeneity associated with the parasite. This
 becomes especially important in generalist dispersal systems; however, so
 far, we do not know the implications of mistletoe spatial heterogeneity on
 the seed-dispersal pattern of other plants with which they simultaneously
 fruit. In a Mediterranean pineland, we analyse the impact of Viscum album
 subsp. austriacum on the seed-deposition pattern of a zoochorous plant
 community, taking into consideration the spatial and temporal variability
 of environmental factors influencing the frugivore's habitat use,
 such as fruit availability and forest tree density. For four consecutive
 years, we studied 55 pairs of trees parasitized and unparasitized by
 mistletoe, analysing zoochorous fruit availability, frugivore visits and
 the zoochorous seed rain in selected trees. As expected, frugivorous birds
 responded to mistletoe heterogeneity by visiting parasitized trees
 preferentially to unparasitized ones, generating a differential deposition
 of mistletoe seeds on tree branches while dispersing seeds of co-fruiting
 species under the host canopy. Availability of understory fruits remained
 similar in patches of parasitized and unparasitized trees, but showed
 strong temporal fluctuations reflected in the seed rain. On the other
 hand, mistletoe proved more copious in patches of parasitized trees and
 their fruit crops varied little between years, making mistletoes reliable
 food resources likely to lead to consistency in fruit-deposition patterns.
 In conclusion, mistletoes, by patchily growing on the canopy layer and
 concentrating zoochorous seeds underneath, can shape the spatial
 seed-deposition pattern of fleshy-fruited plants in the forest. Moreover,
 as seeds constantly reach the same deposition sites over long periods, the
 soil beneath the host canopy could become hotspots for community
 regeneration. In degraded areas, such mistletoe effects might be critical,
 possibly promoting recolonization and vegetation recovery through the
 frugivore's activity.
description: Fruit availability,
 forest structure, visits of frugivore birds and seed
 rainThe following file
 includes data of vegetation structure, fruit availability, frugivore
 activity and dispersed seeds measured in a Mediterranean pineland of
 Southeastern Spain (Natural Park Sierra de Baza) for 4 consecutive years
 (2009-2012).Dryad
 DataFile_1.csvmistletoe seed rain and
 mistletoe seeds stuck on branchesmistletoe seed rain and
 mistletoe seeds stuck on branchesDryad
 DataFile_2.csv