Niche breadth specialization impacts ecological and evolutionary adaptation following environmental change

Area of Science:

• Ecology
• Microbiology
• Evolutionary Biology

Background:

• Ecological theory links adaptation to environmental change with organism distribution and abundance.
• Eukaryotic specialists and generalists are predicted to dominate extreme environments and changing environments, respectively.
• This theory is understudied in prokaryotes, particularly archaea, which are key to global biogeochemical cycles.

Purpose of the Study:

• To test the ecological concept of specialization and generalism in Thaumarchaeota (archaea).
• To investigate archaeal adaptation to environmental change using pH niche breadth as a specialization metric.
• To explore the evolutionary balance between generalism and specialism in archaea.

Main Methods:

• Empirical determination of archaeal growth and activity responses to pH disturbance in long-term, manipulated soil plots.
• Analysis of specialist and generalist distribution across a pH range.
• Investigation of diversification and transition rates between generalist and specialist strategies over evolutionary history.

Main Results:

• Specialists were unevenly distributed and more restricted to extreme pH ranges.
• Generalists exhibited greater adaptation to environmental change than specialists, except when conditions became more extreme.
• Specialists and generalists diversified at similar rates, but transitions from generalism to specialism were more frequent than the reverse.

Conclusions:

• The study provides evidence for the ecological concept of specialism and generalism in prokaryotes, specifically archaea.
• Archaea demonstrate varied adaptation strategies to environmental change, with generalists showing higher plasticity.
• Metabolic specialism appears easier to evolve than metabolic versatility in archaea, influencing their long-term ecological strategies.