Litter quality and interactive effects in litter mixtures: more negative interactions under elevated CO₂?

Abstract

Summary 1The decomposition rate of litter mixtures can depend on interactions between compounds in the component species, i.e. in litter chemistry. Differences in litter N concentration are likely to lead to positive interaction (i.e. faster than expected decomposition) and differences in phenolic concentrations to a negative interaction. These interactions may become less positive (or more negative) when the litter is produced under elevated atmospheric CO 2 concentrations. 2 We measured respiration rates of litter from two contrasting species pairs, produced under ambient and elevated CO 2 . 3 As expected, mixtures of Calamagrostis epigejos and Vicia lathyroides , which differed strongly in litter N concentration, decomposed faster than expected, but the interaction disappeared under elevated CO 2 . 4 Despite the large difference in litter N concentration between Sphagnum recurvum and Carex rostrata , no interaction was observed in the ambient CO 2 litter mixtures, and under elevated CO 2 , there was an unexpected positive interaction. 5 Interactions in litter mixtures can therefore change under elevated CO 2 , albeit not in a predictable manner, which would require correct prediction of species-specific litter chemistry and its response to elevated CO 2 .

Biodiversity at the plant–soil interface: microbial abundance and community structure respond to litter mixing

“…The hypotheses proposed to mechanistically explain synergisms in multi-species leaf litter decomposition include physical (Hansen and Coleman 1998;Gartner and Cardon 2004), chemical (Seastedt 1984;McTiernan et al 1997;Wardle et al 1997;Hoorens et al 2003;Schimel and Hättenschwiler 2007;Meier and Bowman 2008), microbial (Blair et al 1990;McArthur et al 1994;Bardgett and Shine 1999) and macrofaunal mechanisms (Hansen and Coleman 1998;Kaneko and Salamanca 1999;Hättenschwiler and Gasser 2005;Swan and Palmer 2006;Wardle et al 2006), or some combination of the above. While there have been some studies of how microbes respond to litter mixing (Blair et al 1990;Bardgett and Shine 1999;Kominoski et al 2007Kominoski et al , 2009Keith et al 2008), our understanding of how both microbial community composition and abundance can be altered by litter diversity, and potentially change litter decomposition, is limited (van der Heijden et al 2008).…”

Adequacy assessment of mathematical models in the dynamics of litter decomposition in a tropical forest Mosaic Atlantic, in southeastern Brazil

“…It is the main way for organic matter and nutrients cycling (Stocker et al, 1995), for providing more stability to the system (Jordan and Kline, 1972). The nutrient mineralization provided by soil degradation of biomass growth largely determines the characteristics of dominant species in an ecosystem (Hoorens et al, 2002). Although tropical ecosystems show nutrient cycling fast (Wood et al, 2009), the litter production and decomposition depends to the type and succession ecosystem stage (Olson, 1963).…”

Decomposição do folhedo em reflorestamento ciliar na bacia hidrográfica do rio São Francisco, Minas Gerais

“…Entretanto, em vista da grave condição de preservação das matas ciliares, com o consequente comprometimento da qualidade ambiental das bacias hidrográficas, é urgente o desenvolvimento de modelos que visem não só à recuperação estrutural da vegetação ciliar, mas que considerem também a reabilitação de suas características eco-fisiológicas, especialmente relacionadas à ciclagem de nutrientes e matéria orgânica, por se tratar de um processo essencial na restauração e manutenção da fertilidade do solo, capazes de conferir maior estabilidade ao sistema (JORDAN; KLINGE, 1972). Dessa forma, o entendimento dos processos ecológicos que regulam a decomposição da serapilheira e a consequente ciclagem de nutrientes minerais e orgânicos é essencial para garantir o sucesso de reflorestamentos ciliares, pois a decomposição da serapilheira e a subsequente mineralização dos nutrientes, determinam fortemente o crescimento e as características de degradabilidade das espécies vegetais dominantes em um ecossistema (HOORENS et al, 2002). Entretanto, pouco se sabe sobre os processos ecológicos que regulam a ciclagem de nutrientes e minerais nesses ambientes, o que dificulta a implementação de estratégias para a recuperação das matas ciliares.…”