Lakeside daisy (Hymenoxys herbacea) COSEWIC assessment and update update status report: chapter 8
Limiting Factors and Threats
From the above discussion, it is apparent that a number of factors can potentially limit the population size of H. herbacea. Natural limits include herbivory, dispersal ability and the ability to reproduce. Insects (including grasshoppers, beetles and caterpillars), seed-eating birds, cotton-tail rabbits and white-tailed deer all consume the floral head, thereby reducing the number of seeds produced in any given year. As the plant disperses seed primarily via gravity, its ability to colonize new habitats is restricted. In order to maintain seed production, a minimum number of self-incompatibility alleles must be maintained within the population in order to maintain a minimum number of compatible mates. Native bee pollinator guilds are known to influence seed production in Bruce Peninsula populations and should their numbers decline, so too would the daisy’s ability to reproduce. Finally, human activity, in the form of hikers, cottagers and quarrying companies, influences the habitat of H. herbacea to varying degrees. Many populations of H. herbacea (especially on the Bruce Peninsula) come into contact with humans on a daily basis during the summer months.
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