Viewing Fragmentation through the Disease Triangle: Implications for Pathogen Pressure on Seeds.

Area of Science:

• Ecology
• Plant Pathology
• Conservation Biology

Background:

• Landscape fragmentation influences plant diversity and disease dynamics.
• The impact of fragmentation on the plant-pathogen interaction, particularly soilborne diseases, remains under-investigated.
• Fragmentation affects hosts, pathogens, and abiotic conditions, key components of the disease triangle.

Purpose of the Study:

• To investigate how landscape fragmentation affects soilborne plant disease pressure.
• To understand the influence of habitat type (small patches, large patch edges, large patch interiors) on the disease triangle components.
• To assess the consequences of fragmentation-driven disease variation on seed germination and survival.

Main Methods:

• Field surveys of plant and fungal communities in a experimentally fragmented landscape.
• Isolation and identification of fungi from buried seeds across different habitat types.
• Seed germination trials with and without fungicide treatment to assess pathogen impact.

Main Results:

• Habitat type significantly influenced plant and fungal communities, as well as abiotic factors like temperature range.
• Extreme temperature ranges negatively impacted seed germination.
• Fungicide application improved germination for some species, with benefits varying by habitat, indicating habitat-specific disease effects.

Conclusions:

• Patch size alters the ecological context of plant disease by affecting all components of the disease triangle.
• Disease impacts on seed germination are not uniform across fragmented landscapes.
• Understanding fungal-mediated seed survival is crucial for biodiversity in fragmented ecosystems.