Non-native spiders change assemblages of Hawaiian forest fragment kipuka over space and time

By

Pétillon, Julien, 1979-
Kaïna, Privet
Roderick, George
Gillespie, Rosemary G., 1957-
Price, Don

Type

Article

Date of Publication

2020

Original Publication

NeoBiota : advancing research on alien species and biological invasions

Volume

55

Pages

1--9

Subjects

Araneae , diachronic study , Island

Contributed by

Pensoft Publishers

Language

English

Published by

Sophia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/neobiota.55.48498

 

Abstract

We assessed how assemblages of spiders were structured in small Hawaiian tropical forest fragments (Hawaiian, kipuka) within a matrix of previous lava flows, over both space (sampling kipuka of different sizes) and time (comparison with a similar study from 1998). Standardized hand-collection by night was carried out in May 2016. In total, 702 spiders were collected, representing 6 families and 25 (morpho-)species. We found that the number of individuals, but not species richness, was highly correlated with the area of sampled forest fragments, suggesting that kipuka act as separate habitat islands for these predatory arthropods. Species richness was significantly lower in the lava matrix outside the kipuka compared to the kipuka habitats, although there was no statistical difference in species composition between the two habitats, largely because of similarity of non-native species in both habitats. Over the last 20 years, the abundance of non-native spider species substantially increased in both kipuka and lava habitats, in marked contrast to the vegetation that has remained more intact. With endemicity of terrestrial arthropods reaching over 95% in native forests, non-native predatory species present a critical challenge to the endemic fauna.