Survival and growth of Allium tricoccum AIT. Transplants in different habitats

Abstract

Southern Quebec (Canada) represents the northern limit of distribution of Allium tricoccum Ait., a forest spring ephemeral. In this region, Allium tricoccum is considered to be a ‘vulnerable’ plant because of commercial exploitation of natural populations. In order to gain a better understanding of its ecology, and therefore also its protection, a transplantation experiment in seven natural sites (forest and field) and one in a garden, involving bulbs and seeds, was carried out between 1985 and 1990. The objectives were to determine (1) which environmental factors (light availability, soil moisture and soil nutrient levels) most strongly affect the survival and growth of A. tricoccum and (2) which developmental stages are most susceptible to the adverse effects of the environmental factors studied. Separate redundancy analyses were performed on demographic parameters (such as growth and mortality rates) of both juvenile and adult transplants to determine the importance of each environmental factor. Transplants, except for seedlings, showed low initial mortality rates. Transplantation shock appeared to be minimal. Seedling emergence rate was site-specific and was mostly influenced by soil moisture. Summer drought prolonged seed dormancy. Redundancy analyses showed that soil moisture was the most important environmental factor affecting survival and growth of the transplants, whereas light availability did not significantly affect survival and growth. High soil nutrient levels appeared to help maintain growth of both juveniles and adult transplants. These results showed that A. tricoccum may be flexible enough to grow under various environmental conditions, not necessarily just under forest canopies. A. tricoccum could be grown in open agricultural fields due to its tolerance to full sunlight as long as abundant soil moisture is available.