Abstract
Lightning strikes are a common source of disturbance in tropical forests,
and a typical strike generates large quantities of dead wood.
Lightning-damaged trees are a consistent resource for tropical saproxylic
organisms (i.e., dead wood dependent), but patterns of consumer
colonization and succession following lightning strikes are not known.
Here, we explored temporal variation in the occurrence of four common
consumer taxa that span multiple trophic levels—beetles, Azteca ants,
termites, and fungi—in lightning strike sites and nearby undamaged control
sites in a lowland forest of Panama. Beetle abundance was 10 times higher
in lightning strike sites than in paired control sites, and beetle
assemblages were compositionally distinct. Beetle assemblages were
initially dominated by bark and ambrosia beetles (Curculionidae:
Platypodinae, Scolytinae), and predators (including bark and ambrosia
beetle specialist predators) increased in abundance relatively
synchronously. At the tree-level, beetle activity and fungal fruiting
bodies respectively were 3.8 and 12.2 times more likely to be observed in
lightning-damaged trees in lightning strike sites vs. undamaged trees in
paired control sites, whereas the occurrence probabilities of Azteca ants
and termites were similar between lightning-damaged trees in lightning
strike sites and undamaged trees in control sites. Tree size also was
important; larger dead trees in strike sites were more likely to support
beetles, termites, and fungal fruiting bodies, and larger trees—regardless
of mortality status—were more likely to host Azteca. Beetle presence was
associated with higher rates of subsequent fungal presence, providing some
evidence of beetle-associated priority effects on colonization patterns.
These results indicate that lightning plays a key role in supporting
tropical insect and fungal consumers by providing localized patches of
suitable habitat. Any climate-driven changes in lightning frequency in
tropical forests will likely affect a broad suite of consumer organisms,
potentially altering community and ecosystem-level processes.
