Using demographic findings to compare wild and translocated populations of Florida goldenaster (Chrysopsis floridana) in west‐central Florida, U.S.A.

Abstract

Evaluation of the success of rare plant introductions requires analysis of demographic success. We analyze the success of 10 wild and 8 introduced populations of Florida goldenaster (Chrysopsis floridana), a federally endangered forb endemic to west‐central Florida, using demographic and stage‐class data collected from 2017 to 2019. We also collected microhabitat data to characterize factors associated with this species' success. Introductions had higher annual survival rates and fecundity than wild populations; plants in scrub plots had higher survival than roadside plants, although fecundity was higher in roadside plants. Seedling recruitment was only higher for scrub plots in 1 year. Chrysopsis floridana occupancy was better predicted by lower soil nutrients and pH, but introduction success did not consistently vary according to soil conditions. Occupied plots had higher cover of bare sand, lichens, and forbs while unoccupied plots had higher cover of litter, shrub, and subcanopy. The presence of higher litter levels (>60%) appeared to significantly lower survival in 2018. Z‐score site ranking suggested a slight disadvantage for wild populations overall, with the two highest ranked sites both being introductions. Conversely, stage‐class data revealed that both wild and introduced populations had high counts across 3 years of sampling. Most of the healthiest populations had received recent fire, suggesting this may be crucial in providing conditions that promote recruitment and occupancy. More information is needed on aspects of fire and fire surrogates that are likely to affect the demography and distribution of this rare species.

Estimating vital rate variation to assess early success of scrub mint translocations

“…(Menges et al, 2008;Menges et al, 2017). By selecting what we considered to be "preferred habitats," we were able to select favorable micro-sites that may have contributed to our early success (Halsey et al, 2017;Ward et al, 2021;Wendelberger & Maschinski, 2016). In addition, the use of healthy plants and initial supplemental water may have increased vital rates in translocations relative to wild populations.…”

“…Based on observations of wild D. christmanii and other Florida scrub congeners (Evans et al, 2008, 2010; Menges et al, 2006; Menges et al, 2019; Peterson et al, 2013), we know their preferred habitat is open gaps, and larger gaps sustain greater abundances (Menges et al, 2008; Menges et al, 2017). By selecting what we considered to be “preferred habitats,” we were able to select favorable micro‐sites that may have contributed to our early success (Halsey et al, 2017; Ward et al, 2021; Wendelberger & Maschinski, 2016). In addition, the use of healthy plants and initial supplemental water may have increased vital rates in translocations relative to wild populations.…”

“…Dicerandra christmanii is a herbaceous perennial species in the Lamiaceae family. It is a Florida endemic listed as endangered at the federal and state levels and ranked as critically imperiled (NatureServe, 2019;USFWS, 1999). The genus Dicerandra includes many rare species and is, by one measure, the rarest genus in the southeastern United States (Estill & Cruzan, 2001).…”

Diminished Seed Banks of Two Endemic Scrub Herbs in Roadside Habitat Belie Their Population Booms: Are Robust Roadside Populations a Conservation Mirage?

“…Though the scrub and roadsides did not significantly differ in their numbers of viable seeds or aboveground plants for Papery Whitlow-wort, roadsides did have fewer viable seeds and more plants than the scrub, suggesting the same higher germination, recruitment, or survival rate may be at play here. As previously discussed, studies have shown that scrub plants survive at reduced rates on roadsides compared to the scrub (Schafer et al 2013, Ward et al 2022; therefore, we believe that high roadside germination or recruitment rates followed by high mortality is a likely explanation for similar numbers of adult plants in scrub and on roadsides.…”

“…There are no studies, to our knowledge, that examine unpaved roads' effect on seed viability, but we provide some hypotheses here. In the Florida scrub, roadside plants survive at lower rates than those in interior habitat (e.g., Schafer et al 2013, Ward et al 2022) so may devote fewer resources to seed production and produce lower-quality seeds. Alternatively, a reduction in seed viability may stem from seeds degrading in the soil or edaphic conditions preventing the germination of viable seeds or perhaps inducing seed dormancy, but more research is needed to form any conclusions.…”