Numerous studies have shown that nitrogen pollution is causing plant biodiversity losses worldwide. Newly published findings of an ecologically realistic 24-year field study involving 108 experimental grassland plots doesn’t bode well for biodiversity conservation efforts—at least for grasslands. During the study’s most recent eight years, experimentally elevated levels of carbon dioxide nearly tripled species losses attributed to the long-term application of simulated nitrogen pollution. Plots receiving added nitrogen saw species richness (number of plant species per plot) reduced by an average of 7% at ambient CO2 levels and by 19% at elevated levels. If rising carbon dioxide generally exacerbates the widespread negative impacts of nitrogen deposition on plant diversity it bodes poorly for conservation of grassland biodiversity worldwide.
news.umich.edu/nitrogen-pollution-and-rising-carbon-dioxide-a-joint-threat-to-grassland-biodiversity/