Parasites and forest chronosequence: Long-term recovery of nematomorph parasites after clear-cut logging

• Nematomorphs and their hosts were investigated along a forest recovery gradient.
• The nematomorphs recovered linearly with forest age after clear-cut logging.
• Cricket hosts recovered, with a peak at around 30 year-old forests.
• Forests and streams should be managed as an integrated system for >50 years.

Temporal scales at which anthropogenic disturbances affect ecosystem linkages are often unclear. The nematomorph parasites tightly link forests to stream ecosystems via manipulation of their terrestrial hosts. We examined the abundance and species/genetic diversities of nematomorphs with their terrestrial hosts along a forest-recovery gradient after clear-cut logging, using a chronosequence. Only one nematomorph species was found from eight watersheds with different forest ages (3–48 years). The nematomorphs suffered local extinction immediately after logging and then increased linearly with forest age. Their relative abundances were highest in September in older forests, but in October in younger forests, suggesting clear-cut logging can cause not only long-term (>50 years) disruption of the magnitude but also timing of the forest–stream linkage mediated by the nematomorphs. Camel crickets (Diestrammena tsushimensis and D. elegantissima), dominant definitive hosts of the nematomorphs, recovered with a peak at around 30-year-old forests, which was insufficient to explain the long-term recovery of the nematomorphs. This study provided an empirical example of the time-scale (>50 years) at which forests and streams should be managed as integrated systems.

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