Disentangling seed availability and establishment filters at alpine treelines through a decade-long field manipulation

Climate warming is expected to increase upslope shifts of alpine treelines globally. However, the ecological filters controlling tree recruitment in the alpine belt remain poorly quantified, limiting accurate predictions of treeline responses to climate change. To fill this gap, we conducted a decade‑long, factorial field experiment at abrupt (Ordesa) and diffuse (Tessó) Pinus uncinata treelines located in the Spanish Pyrenees. Our experimental treatments manipulated seed addition, herbivory exclusion, shrub competition, and soil scarification. We monitored seedling presence and abundance annually and analyzed their interactions with climate variables, specifically growing-season temperature and snow depth. Seedling recruitment at alpine treelines was strongly filter-limited and varied between sites. Seed addition enhanced emergence at both treeline types, with a steeper, density-dependent response at the diffuse treeline. Herbivore exclusion (1-mm mesh) consistently increased densities..., , # Disentangling seed availability and establishment filters at alpine treelines through a decade-long field manipulation

## Description of the data and file structure

This dataset contains all the necessary data for reproducing the results of the research, as described in the associated manuscript: ‘Disentangling seed availability and establishment filters at alpine treelines through a decade-long field manipulation’

### Files and variables

#### File: data_sgs.csv

**Description:** This data records field observations from alpine and treeline ecological experiments. It contains variables describing site conditions, experimental treatments, seedling dynamics, and climatic factors. Each row represents data from one permanent plot in a given observation year.

##### Variables

* Year: the year when the field observation was conducted
* Site: two treeline types are abrupt (Las Cutas) and diffuse (Tessó) treelines
* Zone: the ecological zone of treeline (Alpine tundra and transition)
* P...,