Parent Genotype and Environmental Factors Influence Introduction Success of the Critically Endangered Savannas Mint (Dicerandra immaculata var. savannarum)

Abstract

Species previously unknown to science are continually discovered and some of these species already face extinction at the time of their discovery. Conserving new and rare species in these cases becomes a trial-and-error process and conservationists will attempt to manage them by using knowledge of closely related species, or those that fill the same ecological niche, and then adapting the management program as needed. Savannas Mint (Dicerandra immaculata Lakela var. savannarum Huck) is a perennial plant that was discovered in Florida scrub habitat at two locations in 1995, but is nearly extinct at these locations. We tested whether shade, leaf litter, propagation method, parent genotype, parent collection site, planting date, and absorbent granules influenced survival, reproduction, and recruitment of Savannas Mint in a population of 1,614 plants that we introduced between June 2006 and July 2009 into a state protected site. Survival and reproduction of introduced plants, and recruitment of new plants, was higher in microhabitats in full sun and no leaf litter and lower in partially shaded habitats. The two sites from which parent plants were collected differentially influenced survival and reproduction of introduced plants. These differences in survival and reproduction are likely due to underlying genetic differences. Differential survival of progeny from different parent genotypes further supports the idea that underlying genetics is an important consideration when restoring plant populations. The most successful progeny of parent genotypes had survival rates nearly 12 times higher than the least successful progeny. We speculate that many of these environmental and genetic factors are likely to influence allopatric congeners and other critically endangered gap specialists that grow in Florida scrub and our results can be used to guide their conservation.

Effects of life history and reproduction on recruitment time lags in reintroductions of rare plants

“…Alternatively, the consistently short RTLs in fast species could be linked to the population dynamics expressed in certain combinations of habitat types and growth forms (Salguero-Gómez 2016;Salguero-Gómez et al 2016). In our data set, most short-lived species were heliophytes of pyrogenic subtropical shrublands or savannas, where reintroductions are often coupled with habitat restoration, such as prescribed fire and exotic species or woody encroachment removal (Possley et al 2008;Peterson et al 2013). These postdisturbance environments are known to promote high growth rates and seedling recruitment in short-lived species and species dependent on high light levels (Menges & Quintana-Ascencio 2004).…”

“…; Peterson et al. ). These postdisturbance environments are known to promote high growth rates and seedling recruitment in short‐lived species and species dependent on high light levels (Menges & Quintana‐Ascencio ).…”

“…For example, the short‐lived subtropical suffrutescents ( Chrysopsis floridana and Dicerandra immaculata ) recruited seedlings within the first year after reintroduction (Peterson et al. ), similar to reintroductions with annuals and other short‐lived herbs. High recruitment rates in these subtropical woodies might, in part, reflect their generally greater rates of iteroparity and net reproduction relative to temperate herbs, especially geophytes (Salguero‐Gómez ; Salguero‐Gómez et al.…”

“…On the other hand, once founders reached maturity, growth form alone did not accurately predict RTLs, perhaps because plant life histories vary along 2 independent axes (fast-slow continuum and reproductive strategy), which when considered jointly, shows that species with different growth forms can have similar life-history strategies and population dynamics (Salguero-Gómez 2016;Salguero-Gómez et al 2016). For example, the short-lived subtropical suffrutescents (Chrysopsis floridana and Dicerandra immaculata) recruited seedlings within the first year after reintroduction (Peterson et al 2013), similar to reintroductions with annuals and other shortlived herbs. High recruitment rates in these subtropical woodies might, in part, reflect their generally greater rates of iteroparity and net reproduction relative to temperate herbs, especially geophytes (Salguero-Gómez 2016; Salguero-Gómez et al 2016), which represented a majority of the long-lived herbaceous species in our data set and exhibited much longer RTLs than short-lived woodies.…”

Population viability analysis and the effects of light availability and litter on populations of Cirsium pitcheri, a rare, monocarpic perennial of Great Lakes shorelines

“…Litter accumulation has been shown to decrease seedling emergence in other pioneer species (Dalling and Hubbell, 2002), species of arid and disturbance-prone environments (Fowler, 1988), and other Year-pair summed elasticities of growth (G), stasis or regression (L), and fecundity (F) for stage-based matrices plotted according to Silvertown et al (1993). rare taxa (Stephens et al, 2012;Wall et al, 2012;Peterson et al, 2013). The increased seedling emergence in the lab under high light and the absence of litter indicates a species better-adapted to early successional and disturbance-prone habitats.…”