Understanding the significance of pollen diversity is key to reconstructing plant diversity over long timescales. Here we present quantitative pollen-plant diversity comparisons for a mountainous area of the Western Mediterranean region. Samples were collected between 430-1,865 m elevation and pollen-plant diversity assessed through richness and turnover (beta-diversity) metrics. We found statistically significant relationships between pollen diversity metrics and the diversity of pollen-equivalent plant taxa in the surrounding vegetation. The strongest richness relationships emerged from the exclusion of trees and with standardisation of the sample size (rarefaction) applied to both plant and pollen datasets. Three different metrics for turnover produced similar results, but emphasise different components of beta diversity (replacement vs richness differences). These results pave the way for reconstructing biodiversity trends from pollen sequences, with a number of caveats. Fossil pollen is a potentially rich source of information on past biodiversity in the Mediterranean region.