Abstract Detail

Past Presidents' Symposium: Biodiversity: Past, Present, and Future

Suding, Katharine [1].

The dark side of N: Why nitrogen is dangerous for native plant diversity and what we can do about it.

While the threat of global warming has stamped 'carbon' into the world's consciousness, increased atmospheric deposition of nitrogen (N) and the disruption of the N cycle may be the biggest global change that no one has heard of. While N is essential for plant growth, elevated N levels can cause substantial declines in plant diversity and the dominance of fast-growing, often weedy or invasive, plant species. However, despite a large amount of work documenting the decline in plant diversity in response to N enrichment, we are still largely unable to explain why these impacts occur. What factors cause plant species loss at high nitrogen availabilities? We have generally assumed one mechanism, competitive exclusion, is the key factor driving such declines. I will suggest two other quite probable mechanisms -- stochastic loss of rare species and changed plant-microbial interactions. I present work from a trait-based synthesis across N fertilization experiments in 10 ecosystems and then present experimental work addressing the importance of competition and microbial interactions in one system, alpine tundra. While competitive mechanism are often assumed, our work shows that neutral loss and belowground microbial interactions can play as large, or in some cases, larger roles in species loss and diversity decline due to N enrichment. I will end by presenting some work addressing whether we can reverse N impacts after they occur, and highlight management strategies that may be effective in facilitating recovery.

Broader Impacts:

1 - Univeristy of California Berkeley, Environemental Sciences, Management and Policy, 130 Mulforh Hall #1334, Berkeley, CA, 94720-1334, USA

Keywords:
nitrogen
biodiversity
alpine tundra
microbial
competition
global change
Species richness.

Presentation Type: Symposium or Colloquium Presentation
Session: SY12
Location: Grand Ballroom A/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 4:15 PM
Number: SY12006
Abstract ID:195
Candidate for Awards:None