Data from: Conflicting selection on Cneorum tricoccon (Rutaceae) seed size caused by native and alien seed dispersers

[Usage Notes] DATA_CNEORUM_seed_size_CONTROL_PLANT_ID_climate_vars This file contains the data on seed diameter of Cneorum tricoccon for all the study populations, considering only seeds collected directly from plants (i.e, undispersed seeds). Data on mean anual precipitation and temperature are given. We indicate the different species of disperser present in each population, with an extra-column showing if the disperser is native (in the case of lizards) or exotic (in the case of pine-martens). This is the file we have used to test for differences in seed size among populations and to assess whether this variable is affected by climatic variables. DATA_CNEORUM_seed_size_all_disp_climate_vars This file contains data on seed diameter of Cneorum tricoccon from the different treatments (controls vs defecated/dispersed by each of the three different species: pine martens or either of the two lizards, Podarcis lilfordi or Podarcis pityusensis). In another column we code the treatment as 0 or 1 (indicating control and defecated seeds, respectively). This is the data file used for the seed selection analyses. We also include data on the climatic variables obtained for each population (mean anual precipitation and temperature). DATA_CNEORUM_GERMINATION This file contains data on the germination of seeds of Cneorum tricoccon from the different treatments (control vs dispersed by any of the three species) in each population. Data are given for each separate seed, indicating whether the seed germinated (1) or not (0). Weight (g) of each seed is given in the last column.The disappearance of native seed dispersers due to anthropogenic activities is often accompanied by the introduction of alien species, which may to some extent replace the ecological service provided by the extinct ones. Yet, little empirical evidence exists demonstrating the evolutionary consequences of such alien ‘replacement’. Here, we document the conflicting selection exerted on seed size by two native lizards (Podarcis lilfordi and P. pityusensis) and an alien mammal species (Martes martes), all acting as legitimate seed dispersers of the Mediterranean relict Cneorum tricoccon. While lizards mostly exerted a negative directional selection on seed diameter, especially P. pityusensis, the much larger pine marten exerted positive selection on seed size. Our findings suggest that this among-disperser variation in the selection regimes, together with the occurrence of spatial variation in the presence of each of seed disperser, help to create the geographical variation observed for seed size of C. tricoccon. To our knowledge, this is the first empirical evidence showing opposing selective pressures between native and alien species in the seed dispersal process in an invaded ecosystem.Peer reviewe