Relationships between resource availability and elevation vary between metrics creating gradients of nutritional...

Area of Science:

• Ecology
• Biogeography
• Plant-Animal Interactions

Background:

• Species richness and community composition change with elevation on mountains.
• Productivity hypotheses suggest declining plant biomass limits consumer resources and thus species richness at higher elevations.

Purpose of the Study:

• Investigate resource availability (plant nutritive metrics, biomass, species richness) along an elevational gradient.
• Understand the relationship between plant nutritional metrics, biomass, and species richness.
• Explore mechanisms driving elevational diversity gradients.

Main Methods:

• Ascended three aspects of Helvellyn mountain, UK.
• Measured plant nutritive metrics, plant species richness, and biomass at different elevations.
• Analyzed the relationships between elevation, plant traits, and consumer abundance patterns.

Main Results:

• Observed a linear decline in plant species richness with increasing elevation.
• Found a unimodal relationship between plant biomass and elevation, with peak biomass at mid-elevations.
• Nutritive values generally decreased with elevation, except for mineral content; however, intra- and inter-specific variations were noted.
• Different nutritive metrics showed distinct relationships with elevation.

Conclusions:

• Elevational diversity gradients are complex, influenced by multiple plant nutritive metrics and consumer requirements.
• Physiological, phenological, and compositional mechanisms likely play roles in observed nutritional variations.
• Propose the 'nutritional complexity hypothesis' where plant nutritional variation drives consumer species coexistence and diversity.