Plants critical for Hawaiian land snail conservation: arboreal snail plant preferences in Puʻu Kukui Watershed, Maui

Wallace M Meyer,D PomaikaʻI Kaniaupo-Crozier,Tricia C Goulding,Lily M Evans,John Slapcinsky,Norine W Yeung,David G Robinson,Connor J.K Kalahiki,Kenneth A Hayes,Jaynee R Kim

doi:10.1017/s0030605320000873

Abstract

AbstractThe Hawaiian archipelago was formerly home to one of the most species-rich land snail faunas (> 752 species), with levels of endemism > 99%. Many native Hawaiian land snail species are now extinct, and the remaining fauna is vulnerable. Unfortunately, lack of information on critical habitat requirements for Hawaiian land snails limits the development of effective conservation strategies. The purpose of this study was to examine the plant host preferences of native arboreal land snails in Puʻu Kukui Watershed, West Maui, Hawaiʻi, and compare these patterns to those from similar studies on the islands of Oʻahu and Hawaiʻi. Concordant with studies on other islands, we found that four species from three diverse families of snails in Puʻu Kukui Watershed had preferences for a few species of understorey plants. These were not the most abundant canopy or mid canopy species, indicating that forests without key understorey plants may not support the few remaining lineages of native snails. Preference for Broussaisia arguta among various island endemic snails across all studies indicates that this species is important for restoration to improve snail habitat. As studies examining host plant preferences are often incongruent with studies examining snail feeding, we suggest that we are in the infancy of defining what constitutes critical habitat for most Hawaiian arboreal snails. However, our results indicate that preserving diverse native plant assemblages, particularly understorey plant species, which facilitate key interactions, is critical to the goal of conserving the remaining threatened snail fauna.

Highlights

Information on how resources influence the abundance and distribution of invertebrate species is often limited (Cardoso et al, )
Understanding which plant species are preferred hosts for arboreal snails is key to determining which combination of native plant species can facilitate preservation of native snail diversity, and alternatively, how changes in abundance of native plant species can influence native snail populations (Meyer et al, )
Consistent preference for B. arguta among various island endemic snails on three islands (Brown et al, ; Meyer, ; Meyer et al, ) indicates that this plant species is critically important in restoration to improve snail habitat

Summary

Introduction

Information on how resources influence the abundance and distribution of invertebrate species is often limited (Cardoso et al, ). Understanding which plant species are preferred hosts for arboreal snails is key to determining which combination of native plant species can facilitate preservation of native snail diversity, and alternatively, how changes in abundance of native plant species can influence native snail populations (Meyer et al, ). Preferred host plants are determined by identifying which plants had more snails on them than expected by chance.

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Conclusion