Conservation and re-establishment of Florida panhandle goldenasters (Chrysopsis): II. Growth and reproduction in response to fertilization within a coastal dune restoration context

Abstract

Throughout the eastern US, recommendations for restoration of coastal dune plant communities often include application of fertilizer at the time of planting. We investigated the effects of fertilizer application (0 or 2.5 g) of Osmocote 18N:6P₂O₅:12K₂O (18-6-12) 9-mo formulation on the initial establishment and subsequent growth and reproduction characteristics for Cruise’s goldenaster (Chrysopsis gossypina ssp. cruiseana (Michx.) Elliott [Asteraceae]) during multiple years (January 2017-2018 and January 2018-2019) and seasons (spring, fall, and winter) when planted within the back dunes in northwest Florida. Data collected included survival, growth, flowering, and seed production characteristics. Seeds were collected from extant and outplanted plants in winter 2018 to compare seed number, quality (seed class), and germination characteristics. Fertilizer application did not influence survival following outplanting. Survival remained ≥ 80% until winter of year 2 (Y2) when survival dropped to 74%. Fertilized plants represented the largest (widest) plants (40 cm) in fall of year 1 (Y1). More primary stems were recorded on fertilized plants compared to non-fertilized plants across both years (12 stems compared to 5 stems). A higher proportion of plants were observed to be reproductive in Y1 compared to Y2 (94% compared to 42%). Fertilized plants produced more heads per plant than did non-fertilized plants in Y1 thereby increasing the total number of seeds per fertilized plant in Y1. Fertilizer had no effect on the number of Class 1 seeds produced per head. Fertilization did not influence germination of seeds collected from outplanted plants, and no difference in germination was evident for Class 1 seeds collected from outplanted and extant plants.