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Competition intensity as a function of resource availability in a semiarid ecosystem
O Briones1, C Montaña1, E Ezcurra2
1Instituto de Ecología, A.C., Apartado Postal 63, CP 91000, Xalapa, Veracruz, Mexico e-mail: briones@sun.ieco.conacyt.mx, Fax: +52-28-187809, , , , , , MX.
Oecologia
|March 18, 2017
Summary
In arid deserts, plant competition for water is minimal when resources are scarce but intensifies with increased water availability. This study examined competition between Hilaria mutica, Larrea tridentata, and Opuntia rastrera.
Area of Science:
- Ecology
- Plant Biology
- Desert Ecosystems
Background:
- Arid plant communities face harsh conditions, driving resource partitioning or intense competition.
- Dominant Chihuahuan Desert species include Hilaria mutica (grass), Larrea tridentata (shrub), and Opuntia rastrera (cactus).
- Two hypotheses proposed either resource partitioning or strong competition due to water scarcity.
Purpose of the Study:
- To test hypotheses on interspecific competition among three dominant Chihuahuan Desert perennial species.
- To determine how resource availability, particularly water, influences competition intensity.
- To investigate the role of life-form differences in mediating plant interactions.
Main Methods:
- Conducted a 1-year removal experiment manipulating species presence in 10m x 10m plots.
- Performed a watering experiment assessing plant responses under isolated vs. associated conditions after simulated rainfall.
- Monitored water status and growth parameters (twig length, leaf/node production) of H. mutica, L. tridentata, and O. rastrera.
Main Results:
- No competition observed in the removal experiment, suggesting low interaction when water was naturally limited.
- Watering experiment revealed competitive effects: associated L. tridentata showed reduced water potential and growth.
- O. rastrera also experienced negative effects on osmotic potential when in proximity to neighbors.
Conclusions:
- Interspecific competition for water in this desert system is highly dependent on soil resource availability.
- Competition is minimal during dry periods but intensifies significantly after substantial rainfall events.
- The study highlights the dynamic nature of plant interactions influenced by fluctuating environmental conditions.
Keywords:
Chihuahuan Desert ecologyHilaria muticaKey words Plant competitionLarrea tridentataOpuntia rastreraMore Related Videos
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