Data for: Response of boreal plant communities and forest floor carbon fluxes to experimental nutrient additions

This is the final dataset for the publication <a href="https://doi.org/10.1007/s10021-023-00899-1">"Response of boreal plant communities and forest floor carbon fluxes to experimental nutrient additions"</a> published in the peer-reviewed journal <i>Ecosystems</i> in 2024. This dataset includes three primary files:<ol><p>
<li>the plant community composition data</li>
<li>the plant functional trait data</li>
<li>the forest floor carbon flux and associated environmental variables data.</li>
</ol>
Combined, the plant community composition data and plant functional trait data were used to calculate the community-weighted mean traits presented in the manuscript. These data explored changes in community-weighted mean traits of both moss and understory vascular plant communities as well as forest floor carbon flux with nutrient fertilization emulating nutrient increases following permafrost thaw in a boreal peatland (Scotty Creek Research Station, NT: 61°18′ N, 121°,18′ W). We had two sites in this boreal peatland: one with high canopy cover, and one with low canopy cover. <p><p>

We conducted an experiment whereby we set up 25, 0.5 m^2 quadrats at two sites within a boreal peatland (50 total quadrats). We had five different nutrient treatments with five replicates each: an unmanipulated control (no fertilizer or mechanical disturbance), a manipulated control (no fertilizer, with mechanical disturbance similar to the fertilized treatments), shallow fertilization (nutrient added at 20cm soil depth emulating increasing microbial mineralization with warming soil), deep fertilization (nutrient added at 40 cm soil depth emulating release of previously frozen nutrient-rich soil to the active layer), and shallow + deep fertilization (emulating both the shallow and deep treatments simultaneously). 12-4-8 NPK MiracleGro slow-release fertilizer was applied at a dosage of 6 g N m-2. This value is roughly four times that of the predicted maximum rate of increase in N from rising soil temperature and permafrost thaw (e.g., 1.3 g N m-2 yr-1; Keuper and others 2012, <i>Global Change Biology</i> 18: 1998) but is similar to Keuper and others (2017, <i>Global Change Biology</i> 23: 4257). Furthermore, being slow-release fertilizer, we expected slow nutrient release over the two-year experiment, mimicking natural conditions. The two sites whereby we set up the experiment differed in canopy cover and therefore allowed us to test if light availability effected the response of carbon fluxes and plant communities to nutrient increases. See (link to paper) for more detailed methodology.