Gardening for Wildlife: Are Native Plant Cultivars as Effective as Native Plants Propagated from Local, Wild Populations for Promoting Native Insect Diversity?

摘要

Many gardeners concerned over recent declines in biodiversity in suburban areas are attempting to improve the ecological functioning of their landscapes by incorporating native plants. Native plants are important food sources for native herbivorous insects, and insects are in turn important food sources for animals in higher trophic levels. But do the native plants available in nurseries, typically cultivated varieties (cultivars) of a single genotype, fill an equivalent ecological role as the local,wild-type plants? For two herbaceous perennials, we observed significant differences in both total insect abundance and total number of insect species. However, there was a significant interaction between plant species and plant origin, suggesting thatinsect abundance and diversity does not depend on the source of the plant material per se, but rather on the particular characteristics of the cultivar that distinguish it from the wild form. We also observed significant differences in the insect communities among treatments, though only a small proportion of the total insect species collected contributed to these differences. Identifying which characteristics of cultivars might predict a loss of ecological function will not only help gardeners make the best choices of plants for their landscapes, but also will enable horticulturalists to select cultivars that potentially outperform the wild-type plants in terms of the ecological services they provide.