Long-term nutrient addition and grazing exclusion determine flower abundance, diversity and community composition in high-latitude grasslands

The abundance and composition of flowers within plant communities shape the resources available to flower-visiting insects. However, it remains unclear how nutrient enrichment and changes in grazing impact plant communities and their floral resources, and whether these effects contribute to ongoing pollinator decline. We investigated how the abundance, diversity, and species composition of flowers (excluding graminoids) respond to long-term nutrient additions and grazing exclusion in two high-latitude grasslands (tundra and montane). We used two factorial experimental designs: 1) a nutrient experiment with additions of nitrogen (N), phosphorus (P), and potassium (K with micronutrients, and 2) a grazing experiment that included combined NPK addition with and without grazing exclusion. Flower abundance was assessed in 5 × 5 m experimental plots after 6–10 years of treatments. N and P interactively affected flower abundance, with N counteracting the positive effects of P. N reduced flower ..., , # Long-term nutrient addition and grazing exclusion determine flower abundance, diversity, and community composition in high-latitude grasslands

**Metadata of flower_unit_data.csv:**

* Site = factor with two levels: the tundra (kilp.fi) and the montane (saana.fi) site

- Block = factor with four levels: the number of the block

* Blocks = factor with four levels: the number of the block separated for kilp.fi (k) and saana.fi(s) sites

- Block_Plot = plot code

* Plot_nr = plot number within the site

- N = factor of addition, levels '1=yes' or '0=no'

* P = factor of P addition, levels '1=yes' or '0=no'

- K = factor of K addition with micronutrients, levels '1=yes' or '0=no'

* Fence = factor grazing exclusion, levels '1=yes' or '0=no'

- NPK = factor NPK addition, levels '1=yes' or '0=no'

* treatm = treatment code

- treatm4 = factor to subset data with NPK-Fence treatments

* treatm8 = factor to subset data with N, P, K addition treatments

- species columns (N-BL) mean flower abu...,