Modern pollen rain of an upland area: implications of pollen dispersal for interpreting palaeoenvironmental records

A long‐term perspective on landscape evolution is critical for understanding past land‐use activity, land cover–climate feedbacks and, notably, for establishing a factual basis for conservation. Fossil pollen analysis provides a means to achieve this. Biases pertaining to pollen productivity, pollination processes and basin size, however, mean there is not a one‐to‐one relationship between pollen and plant presence. Upland pollen recruitment is poorly understood, and existing studies of pollen dispersal have yielded conflicting results, making interpreting past landscape character challenging. Here, we report on the modern pollen rain of the Mourne Mountains, Northern Ireland, relative to local and regional vegetation to investigate the signal that upland pollen spectra capture. We find that long‐distance pollen transport is prevalent, comprising an average of 56% of total dryland pollen for sites where the local vegetation is open, and controlled by a positive relationship with elevation. An abundance of regionally sourced arboreal pollen and dominance of pollen from some locally growing taxa poses challenges for interpreting local landscape character as locally growing herbaceous taxa, isolated trees and extra‐local woodland are diminished in pollen spectra. We show that arboreal pollen abundance around 80% is indicative of locally growing, semi‐closed woodland, but this should be accompanied by low palynological richness and evenness to firmly ascribe this habitat type. Despite the complex signal that upland pollen spectra represent, we show vegetation can be reliably interpreted from pollen with careful consideration of a site's setting in the landscape. This study further highlights the importance of studying modern pollen rain samples with respect to local and regional vegetation and provides insights that aid interpretation of palaeoecological studies in upland areas globally.