Spatial scale dependence of factors driving climate regulation services in the Americas

Aim: A key hypothesis in macroecology is that the relative importance of factors driving ecological phenomena changes with spatial scale. However, studies on ecosystem services usually ignore this. Here, we test how the importance of factors related to climate regulation services varies with spatial extent (i.e., area of assessment) and how covariation among factors affects scale dependencies. Location: The Americas. Time period: Present. Major taxa studied: Plants. Methods: We combined a multi‐model inference framework with variance partitioning to quantify the importance of factors that could potentially influence climate regulation services (i.e., albedo, evapotranspiration and primary productivity). We quantified abiotic (climate, soil, heterogeneity in soils/topography), biotic (open vegetation, forest area and biomass, plant functional traits) and anthropogenic (forest fragmentation, managed vegetation, non‐vegetated surfaces) conditions and tested their importance in relation to climate regulation services at spatial extents ranging from 9 × 103 to 1 × 106 km2. Results: We found that the importance of abiotic factors in relation to climate regulation services increases with spatial extent. However, we found no evidence for a change from primarily biotically to abiotically driven climate regulation services with increasing spatial extent. All spatial extent dependencies were heavily influenced by covariation between abiotic, biotic and anthropogenic factors. After accounting for covariation, we found a primacy of abiotic factors as drivers of climate regulation services across spatial extents. Biotic and anthropogenic factors were less important than abiotic factors, and their independent effects were conserved across spatial extents. Main conclusions: Our results show that the relative importance of abiotic factors related to climate regulation services depends on spatial extent. Biotic and anthropogenic factors are less important for climate regulation services than abiotic factors, and this hierarchy is scale invariant. Our findings suggest that spatial extent dependence needs to be quantified and assessed in climate‐change mitigation projects that focus on ecosystem services.