Data from: Seed dispersers help plants to escape global warming

Plants are shifting their ranges towards higher elevations in response to
global warming, yet such shifts are occurring at a rate slower than is
needed to keep pace with a rapidly changing climate. There is, however, an
almost complete lack of knowledge on seed dispersal across altitude, a key
process to understand what constrains climate-driven range shifts. Here,
we report the first direct empirical evidence on altitudinal seed
dispersal mediated by two common frugivorous mammals: the red fox Vulpes
vulpes and the pine marten Martes martes. We conducted a three-year
(bait-marking) experiment in a mountainous region of Spain. We offered
experimental fruits containing colour-coded seed mimics at feeding
stations that simulated source trees. The colour codes allowed us to
identify the exact origin of seed mimics found later in mammal scats.
Nearly half (47%) of the dispersal events occurred towards higher
elevations, despite only ca 25% of the study area being above the average
altitude of the feeding stations (1344 m). Seeds dispersed uphill gained
an average of 106 m (median = 111 m) and a maximum of 288 m, greatly
exceeding the estimated requirements to escape warming (35.4 m per
decade). Yet, foxes mediated much more uphill seed dispersal than martens
(57% and 26% of dispersal events, respectively), which can be explained by
between-disperser differences in home range size and habitat specificity.
Dispersers with larger home ranges move farther and potentially disperse
more seeds to higher altitudes, while habitat generalism is necessary to
transport seeds above vegetation belts delimiting contrasting habitat
types. We discuss how both traits (home range size and habitat
specificity) can be used to infer altitudinal seed dispersal across
disperser species and mountainous landscapes.