Entomology

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Author: search.filters.author.Bracken, MatthewSubject: search.filters.subject.phosphorus

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    Nutrient co-limitation of primary producer communities
    (Blackwell, 2011) Harpole, Stanley; Ngai, Jacqueline; Cleland, Elsa; Seabloom, Eric; Borer, Elizabeth; Bracken, Matthew; Elser, James; Gruner, Daniel; Hillebrand, Helmut; Shurin, Jonathan; Smith, Jennifer
    Synergistic interactions between multiple limiting resources are common, highlighting the importance of co-limitation as a constraint on primary production. Our concept of resource limitation has shifted over the past two decades from an earlier paradigm of single-resource limitation towards concepts of co-limitation by multiple resources, which are predicted by various theories. Herein, we summarise multiple-resource limitation responses in plant communities using a dataset of 641 studies that applied factorial addition of nitrogen (N) and phosphorus (P) in freshwater, marine and terrestrial systems. We found that more than half of the studies displayed some type of synergistic response to N and P addition. We found support for strict definitions of co-limitation in 28% of the studies: i.e. community biomass responded to only combined N and P addition, or to both N and P when added separately. Our results highlight the importance of interactions between N and P in regulating primary producer community biomass and point to the need for future studies that address the multiple mechanisms that could lead to different types of co-limitation.
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    Global analysis of nitrogen and phosphorus limitation of primary producers in freshwater, marine and terrestrial ecosystems
    (Ecology Letters, 2007-12) Elser, James; Bracken, Matthew; Cleland, Elsa; Gruner, Daniel; Harpole, Stanley; Hillebrand, Helmut; Ngai, Jacqueline; Seabloom, Eric; Shurin, Jonathan; Smith, Jennifer
    The cycles of the key nutrient elements nitrogen (N) and phosphorus (P) have been massively altered by anthropogenic activities. Thus, it is essential to understand how photosynthetic production across diverse ecosystems is, or is not, limited by N and P. Via a large-scale meta-analysis of experimental enrichments, we show that P limitation is equally strong across these major habitats and that N and P limitation are equivalent within both terrestrial and freshwater systems. Furthermore, simultaneous N and P enrichment produces strongly positive synergistic responses in all three environments. Thus, contrary to some prevailing paradigms, freshwater, marine and terrestrial ecosystems are surprisingly similar in terms of N and P limitation.