Juvenile animals generally disperse from their birthplace to their future breeding territories. In fragmented landscapes, habitat-specialist species must disperse through the anthropogenic matrix where remnant habitats are embedded. Here, we test the hypothesis that dispersing juvenile frugivores leave a footprint in the form of seed deposition through the matrix of fragmented landscapes. We focused on the Sardinian warbler (Sylvia melanocephala), a resident frugivorous passerine. We used data from field sampling of bird-dispersed seeds in the forest and matrix of a fragmented landscape, subsequent disperser identification through DNA-barcoding analysis, and data from a national ringing programme. Seed dispersal by Sardinian warblers was confined to the forest most of the year, but warblers contributed a peak of seed-dispersal events in the matrix between July and October, mainly attributable to dispersing juveniles. Our study uniquely connects animal and plant dispersal, demonstrating that juveniles of habitat-specialist frugivores can provide mobile-link functions transiently, but in a seasonally predictable way.
Seed rain contributions
Relative and absolute contributions – according to DNA-barcoding identifications – of Sardinian warblers (Sylvia melanocephala) and other bird species to the bimonthly magnitude of seed deposition per seed trap, bimonth and year, of different plant species.
seed_rain_contr_syl_mel_and_other_spp.csv
Seed rain data
Total number of seeds (all species pooled; zeros included) per seed trap, bimonth and year, estimated as dispersed by Sardinian warblers (and other bird species) according to DNA-barcoding identifications. This is the dataset associated to Figure 1c and Figure 2.
seed_rain_syl_mel_and_other_spp.csv
Habitat classification ringing data
Classification of the original habitat types associated to each ringing capture into habitats analogous to the forest (i.e. woodland habitats) and matrix (i.e. open habitats) of our study landscape.
The original ringing data used in this study can be requested to SEO/BirdLife (www.anillamientoseo.org).
classification_habitats_ringing_data.csv
Ringing captures & Mean seed rain
Accumulated number of bimonthly ringing captures of juvenile and adult Sardinian warblers (Sylvia melanocephala) between 1975 and 2018, in a subset of the warm Spanish provinces dominated by the thermo- and meso-Mediterranean bioclimate, in relation to bimonthly mean seed rain dispersed by Sardinian warblers in our study landscape (data associated to Figure 2 in the article).
The original ringing data used in this study can be requested to SEO/BirdLife (www.anillamientoseo.org).
ringing_captures_vs_mean_seed_rain.csv
DNA barcoding data
Seed-deposition samples (bird droppings with seeds, defecated or regurgitated) analysed through DNA barcoding to identify the bird species responsible of seed dispersal events. Disperser identifications are classified as Sardinian warbler (Sylvia melanocephala) versus other bird species. Only those samples that were dispersed by Sardinian warblers (i.e. the ones used in this study) include fields for sequence, sequence length and source of barcoding identification.
dna_barcoding_data.csv
