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Biomass accumulation and resource utilization in co-occurring grassland annuals
H A Mooney1, R J Hobbs2, J Gorham1
1Department of Biological Sciences, Stanford University, 94305, Stanford, CA, USA.
Oecologia
|March 18, 2017
Summary
Plant life spans and reproduction strategies in California serpentine soils are strongly influenced by soil moisture availability. Longer-lived annual plants produce more biomass but a lower proportion of reproductive output.
Area of Science:
- Ecology
- Plant Biology
- Soil Science
Background:
- Mediterranean-climate annuals are adapted to seasonal drought.
- Serpentine soils present unique edaphic challenges, including low moisture retention.
- Plant life history strategies are crucial for survival and reproduction in variable environments.
Purpose of the Study:
- To investigate the impact of soil moisture on the life span and reproductive characteristics of annual plants.
- To compare the life history traits of annuals with differing life spans in serpentine ecosystems.
Main Methods:
- Field observations of annual plant populations in central California serpentine soils.
- Monitoring of soil moisture availability throughout the growing season.
- Measurement of plant life span, total biomass accumulation, and reproductive output.
Main Results:
- Soil moisture significantly affects the life span and reproductive periods of Mediterranean-climate annuals.
- Longer-lived annuals achieved greater lifetime biomass accumulation.
- Annuals with extended life spans exhibited higher total reproductive output but a lower proportional output, alongside elevated leaf C/N ratios at reproduction.
Conclusions:
- Soil moisture is a critical determinant of plant life history strategies in serpentine ecosystems.
- Extended life spans in annual plants can lead to increased overall biomass and altered reproductive investment strategies.
- Leaf carbon-to-nitrogen ratios may serve as an indicator of reproductive strategy under varying moisture conditions.
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