Climate change erodes competitive hierarchies among native, alien and range-extending crabs

Area of Science:

• Marine Biology
• Ecology
• Climate Change Science

Background:

• Global warming and ocean acidification are known to alter animal behaviors.
• The impact of these changes on interspecies resource competition remains poorly understood.

Purpose of the Study:

• To investigate how combined ocean acidification and warming affect feeding success and dominance hierarchies in native, alien, and range-extending crab species.
• To determine if climate change alters competitive interactions and dominance among these crab species.

Main Methods:

• Experimental manipulation of ocean temperature and acidification levels to simulate future climate conditions.
• Observation and quantification of feeding success and time spent feeding for different crab species under current and future conditions.
• Assessment of dominance hierarchies based on feeding success to identify shifts in species interactions.

Main Results:

• Under current conditions, range-extending crab species exhibited higher feeding activity compared to alien and native species.
• Under simulated future climate conditions, no significant difference in feeding time was observed among the three crab groups.
• Behavioral changes led to a reversal in dominance hierarchies, with previously dominant species becoming less dominant and vice versa.

Conclusions:

• Moderate increases in ocean temperature and acidification can lead to a homogenization of behavioral competitiveness among species.
• Climate change-induced behavioral shifts can erode dominance differences crucial for fitness and population persistence.
• These findings challenge predictions of strengthened or reversed dominance, suggesting a potential for reduced competitive disparities in future marine ecosystems.