Safe Sites and the Ecological Life History of Lorinseria Areolata

Abstract

The life history biology of the fern Lorinseria areolata was studied at three sites adjacent to the Escambia River, Florida, which represented part of its habitat diversity in the Gulf Coastal Plain. Site 1 was dominated by Pinus elliottii and was flooded only during hurricanes. Site 2 was dominated by Magnolia virginiana and Gordonia lasianthus and was flooded for 3–5 months of the year. Site 3 was dominated by Nyssa sylvatica var. biflora and Taxodium distichum and was flooded for 9–12 months of the year. Lorinseria areolata coverage was 92, 61, and 16% of total understory at sites 1, 2, and 3. Rhizome length varied 5‐fold between sites. Microtopography varied little at site 1. Microtopography at sites 2 and 3 consisted of distinctive hummocks and hollows. Association analysis documented that L. areolata was distributed randomly with regard to microtopography at site 1, and was strongly associated with hummocks at sites 2 and 3. Seven life history classes (LHCs) for L. areolata were discriminated based on field collections and seasonal observations over three years. Density of LHCs decreased logarithmically, with the exception of older LHCs whose age could not be determined beyond 30 months. Spore storage in dead erect sporophylls allowed the establishment of gametophytes throughout the year. Up to 25% of the gametophyte population survived the cold and relative drought of winter. More than half of field collected gametophytes were small males, and up to a third were larger bisexual gametophytes. Safe sites for completion of the life cycle were limited to decayed pine stumps and twigs at site 1, and to hummocks at sites 2 and 3. It was hypothesized that the acidifying action of Pinus elliottii litter on soil contributed to the abundance of Lorinseria areolata at site 1, and that parts of the microhabitat mosaic at sites 2 and 3 which most closely approached edaphic characteristics of site 1 provided safe sites for the fern.

Geographic distributions of homosporous ferns: does dispersal obscure evidence of vicariance?

“…This is obviously another random process and most spores that disperse probably fail to reach a suitable place. Cousens et al . (1988) discussed these safe sites and noted that species vary considerably in their requirements for germination and gametophyte survival.…”

Life cycle matters: DNA barcoding reveals contrasting community structure between fern sporophytes and gametophytes

“…The importance of microsite availability for establishment of fern gametophytes has been supported by studies in the temperate zones (Cousens et al. , Peck et al. , Flinn ) and the tropics (Watkins et al.…”

“…Investigations of gametophyte ecology prior to the advent of DNA sequencing were limited in scope due to insufficient ability to identify gametophytes to species, either relying on a few species with diagnostic characters, extrapolating from nearby juvenile sporophytes, or growing out sporophytes in the lab (Cousens et al. , Peck et al. , Watkins et al.…”

“…Range sizes were compared on the basis of total elevational range, lowest elevation, highest elevation, occurrence of gametophyte without sporophyte in a given survey plot, and occurrence of gametophyte without a sporophyte match in the reference database. insufficient ability to identify gametophytes to species, either relying on a few species with diagnostic characters, extrapolating from nearby juvenile sporophytes, or growing out sporophytes in the lab (Cousens et al 1988, Peck et al 1990, Watkins et al 2007b. Recently, DNA barcoding has been increasingly applied to identify field-collected fern gametophytes, and has revealed that gametophytes do indeed occur outside of the range of sporophytes in some species (e.g., Chen et al 2013, Ebihara et al 2010, Kuo et al 2016).…”

Microsite effects on forest regeneration in a bottomland swamp in western New York1

“…Differences in species germination, survival, and establishment across microsite types have been attributed to differences in microsite characteristics (Pavone and Reader 1985, Titus 1990, Huenneke and Sharitz 1986, Vivian-Smith 1997, Wall and Darwin 1999, Middleton 2002, presence of moss (Pavone and Reader 1985), individual species tolerances to both competition and disturbance (Zedler and Zedler 1969, Cousens et al 1988, Eldridge 1991, Jordan and Hartman 1995, Pollock et al 1998, Petru and Leps 2000, and escape from flooding (Zedler andZedler 1969, van der Valk 1994). In addition, seed bank and emergent seedling composition, and seedling density vary across microsites as well as across flooding regimes (Parker and Leck 1985, Titus 1991, Abernethy and Willby 1999, Middleton 2000, Peterson and Baldwin 2004b.…”