Factors influencing seedling recruitment in a critically endangered pitcher plant, Sarracenia rubra ssp. alabamensis 

Abstract

Sarracenia rubra ssp. alabamensis is a critically endangered pitcher plant endemic to central Alabama (USA); efforts have been made to protect the remaining populations, including the use of prescribed fire and thinning to restore the savanna-like structure that historically characterized its habitat and to promote the beneficial effects of fire on seedling establishment observed in other pitcher plant species. Despite these efforts, seedling recruitment remains very low within the largest population of S. rubra ssp. alabamensis. We considered the possibility that other factors such as germinability, seed removal (by predators or dispersal agents), and inadequate soil moisture were reducing or preventing seedling recruitment. We report the results of laboratory and field experiments investigating factors limiting seedling recruitment and establishment in the 2 largest remaining populations, which were observed at sites that differed in soil moisture, fire management, and the abundance of sphagnum moss. Seedling recruitment was higher at the wet unmanaged site than at the dry, fire-managed site. The major contributing factors to site differences in recruitment were a greater abundance of safe sites for germination (specifically, patches of sphagnum) and lower seedling mortality at the wet unmanaged site as a result of higher soil moisture. We recommend that land managers shift some of their attention to this and other wet sites and seek permission to increase population density and restore fire at these sites.

Genetic variability and structure of an important wild steppe grass Psathyrostachys juncea (Triticeae: Poaceae) germplasm collection from north and central Asia

“…In return, the progress of inbreeding depression is accelerated in spite of a certain degree of gene flow, which cannot completely compensate for the decrease in diversity caused by a higher inbreeding rate (Wesche & Treiber, 2012;Sui et al, 2009;Liu et al, 2013). Additionally, with the rapid climate changing and habitat destruction, long-lived perennial plants were apt to remain low rates of seedling recruitment remains within the population (Ellis, Weekley & Menges, 2007;Chesser & Brewer, 2011). The possible factors such as high grazing pressure, low germinability, soil drought and seed removal by predators were considered to reduce or prevent seedling recruitment, which ultimately resulted in decrease of populations' size and their genetic diversity (Endels et al, 2007).…”

The impact of neighbourhood and gap character on seedling recruitment of Trollius europaeus L. and Iris sibirica L. in Molinietum caeruleae meadows

“…The seedling recruitment -a critical bottleneck in the population dynamics of numerous rare taxa -becomes one of the most important parameters to be considered in species conservation biology. Although, the phenomenon of offspring emergence was studied in a variety of threatened taxa (e.g Křenová & Lepš 1996;Dinsdale et al 2000;Gulias et al 2004;Chien et al 2008;Chesser & Brewer 2011), further investigations are still strongly desired.…”

Time of Monitoring Influences Detectability and Demographic Estimates of the Threatened Perennial Spalding's Catchfly (Silene spaldingii S. Watson)

“…Seedlings and first-year recruit R plants were often observed in close association with reestablishing mosses, and several R plants were still alive at late monitoring following one of the hottest and driest growing seasons during the study periods. Moss may provide safe sites for germination and help retain soil moisture for subsequent seedling survival, as has been shown for other species (Picó and Riba 2002, Chesser and Brewer 2011, Rayburn et al 2012. Dew deposition on moss may also have aided seedling survival.…”