Plant facilitation of a belowground predator

Area of Science:

• Belowground Ecology
• Plant-Animal Interactions
• Soil Biology

Background:

• Facilitative plant-predator interactions are primarily studied aboveground.
• Distinct underground conditions influence ecological dynamics.
• Predatory nematodes require specific microhabitats for survival.

Purpose of the Study:

• To investigate the role of bush lupine (Lupinus arboreus) in facilitating predatory nematode survival.
• To test the hypothesis that lupine root zones provide a refuge for nematodes during dry periods.
• To assess the impact of this interaction on belowground trophic cascades.

Main Methods:

• Field surveys were conducted to measure nematode survival.
• Nematode survival was assessed in lupine and grassland rhizospheres.
• Experiments were performed under both wet and dry season conditions.
• Population extinction probability was modeled for nematode cohorts.

Main Results:

• Predatory nematode survival was significantly higher under lupines than in grasslands during the dry season.
• This survival advantage diminished in wet, winter soil conditions.
• Nematode population extinction was less likely in lupine rhizospheres compared to grasslands.
• Even small nematode populations showed higher survival rates under lupines.

Conclusions:

• Bush lupine facilitates the survival of the predatory nematode Heterorhabditis marelatus, particularly during dry seasons.
• This plant-nematode facilitation can prevent nematode population extinction and support a belowground trophic cascade.
• Such facilitative interactions in seasonally stressful environments may be widespread in nature.