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Assessing effects of non‐native crayfish on mosquito survival
Author(s) -
Bucciarelli Gary M.,
Suh Daniel,
Lamb Avery Davis,
Roberts Dave,
Sharpton Debra,
Shaffer H. Bradley,
Fisher Robert N.,
Kats Lee B.
Publication year - 2019
Publication title -
conservation biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.2
H-Index - 222
eISSN - 1523-1739
pISSN - 0888-8892
DOI - 10.1111/cobi.13198
Subject(s) - dragonfly , crayfish , predation , biology , nymph , ecology , procambarus clarkii , predator , odonata
s of non‐native predators often reduce biodiversity and affect natural predator–prey relationships and may increase the abundance of potential disease vectors (e.g., mosquitoes) indirectly through competition or predation cascades. The Santa Monica Mountains (California, U.S.A.), situated in a global biodiversity hotspot, is an area of conservation concern due to climate change, urbanization, and the introduction of non‐native species. We examined the effect of non‐native crayfish ( Procambarus clarkii ) on an existing native predator, dragonfly nymphs ( Aeshna sp.), and their mosquito larvae ( Anopheles sp.) prey. We used laboratory experiments to compare the predation efficiency of both predators, separately and together, and field data on counts of dragonfly nymphs and mosquito larvae sampled from 13 local streams. We predicted a lower predation efficiency of crayfish compared with native dragonfly nymphs and a reduced predation efficiency of dragonfly nymphs in the presence of crayfish. Dragonfly nymphs were an order of magnitude more efficient predators than crayfish, and dragonfly nymph predation efficiency was reduced in the presence of crayfish. Field count data showed that populations of dragonfly nymphs and mosquito larvae were strongly correlated with crayfish presence in streams, such that sites with crayfish tended to have fewer dragonfly nymphs and more mosquito larvae. Under natural conditions, it is likely that crayfish reduce the abundance of dragonfly nymphs and their predation efficiency and thereby, directly and indirectly, lead to higher mosquito populations and a loss of ecosystem services related to disease vector control.