Functional composition drives ecosystem function through multiple mechanisms in a broadleaved subtropical forest

Long-term studies have revealed that forest species composition was shifting under environment change and disturbance induced by loss of large trees. Yet, few studies explicitly analyzed their impacts on composition concurrently. To learn more about impacts of environment change and disturbance on driving forest community, we investigated shifts in functional composition over past 24 years in an old-growth subtropical forest in southern China. We analyzed nine traits that are mainly related to leaf nutrients, photosynthetic capacity, hydraulic conductivity, and drought tolerance of plants and examined hypotheses: (1) The functional composition change over time was directional instead of random fluctuation, (2) drought-tolerant species increased their abundance under soil dryness, (3) both environmental change and disturbance related to changes of functional composition significantly, and (4) initial trait values of quadrats strongly influenced their subsequent change rates in quadrat level (10 × 10 m). We found that species composition had shifted to favor species with high leaf nutrient content, high photosynthesis rate, high hydraulic conductivity, low water-use efficiency, and high drought tolerance traits, which was due to soil dryness and disturbance. These two factors explained 47–58% of quadrats’ trait value changes together. Considering rapidly increasing stem density, this pattern may indicate ecological processes of which disturbance provided numerous recruits of resource-acquisition strategy species and soil dryness conducted a selecting effect on shaping composition in the forest. Additionally, quadrats with initial trait values at the far end of change direction shifted faster in three traits, which also indicated that functional composition changes in quadrats were directional and homogenized. Our results implied that environment change and accompanied disturbance events possibly drove species composition change along a different trajectory in the subtropical forest that experienced high climatic variability.

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Shifts in microbial communities do not explain the response of grassland ecosystem function to plant functional composition and rainfall change

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2015.10.006 ◽

2016 ◽

Vol 92 ◽

pp. 199-210 ◽

Cited By ~ 15

Author(s):

Ellen L. Fry ◽

Peter Manning ◽

Catriona Macdonald ◽

Shun Hasegawa ◽

Adriana De Palma ◽

...

Keyword(s):

Microbial Communities ◽

Ecosystem Function ◽

Functional Composition ◽

Grassland Ecosystem ◽

Rainfall Change

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Intraspecific trait changes have large impacts on community functional composition but do not affect ecosystem function

Journal of Ecology ◽

10.1111/1365-2745.13827 ◽

2021 ◽

Author(s):

Noémie A. Pichon ◽

Seraina L. Cappelli ◽

Eric Allan

Keyword(s):

Ecosystem Function ◽

Functional Composition

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Dominance determines fish community biomass in a temperate seagrass ecosystem

10.32942/osf.io/cqjvu ◽

2019 ◽

Author(s):

Aaron Matthius Eger ◽

Rebecca J. Best ◽

Julia Kathleen Baum

Keyword(s):

Species Richness ◽

Ecosystem Function ◽

Fish Community ◽

Prey Capture ◽

Fish Communities ◽

Functional Trait ◽

Ecosystem Functions ◽

Community Biomass ◽

Ecosystem Valuation ◽

Species Abundances

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.

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