9 research outputs found
Endangered plants persist under phosphorus limitation
Nitrogen enrichment is widely thought to be responsible for the
loss of plant species from temperate terrestrial ecosystems. This
view is based on field surveys and controlled experiments showing
that species richness correlates negatively with high productivity,
and nitrogen enrichment. However, as the type of
nutrient limitation has never been examined on a large geographical
scale the causality of these relationships is uncertain. We
investigated species richness in herbaceous terrestrial ecosystems,
sampled along a transect through temperate Eurasia that represented
a gradient of declining levels of atmospheric nitrogen
deposition—from ,50 kg ha21 yr21 in western Europe to natural
background values of less than 5 kg ha21 yr21 in Siberia. Here we
show that many more endangered plant species persist under
phosphorus-limited than under nitrogen-limited conditions, and
we conclude that enhanced phosphorus is more likely to be the
cause of species loss than nitrogen enrichment. Our results highlight
the need for a better understanding of the mechanisms of
phosphorus enrichment, and for a stronger focus on conservation
management to reduce phosphorus availabilit