Naomi N Arcand And Tom A Ranker

10.1 Introduction

Within the USA, Connecticut was the first state to pass a plant protection law in 1869, and it was for a fern: Lygodium palmatum populations were declining due to over-collection for horticultural uses (Yatskievych and Spellenberg, 1993). Over a century later, the same fern was the source of a short article in The New York Times on June 16,1985, which described road relocation negotiations to avoid two patches of the rare Lygodium palmatum in Burlington County, New Jersey (Haitch, 1985). The article reads, "The issue was at a stalemate in December. Score one for the ferns. Burlington will move the road 200 ft. east of the originally planned route to bypass the plants . . ." (Haitch, 1985). The beginnings of the American Fern Society in 1893, followed quickly by the publication of the Fern Bulletin (for 5<j/ each), and later the American Fern Journal in 1910, attest to the early importance of ferns and lycophytes to US aficionados (Benedict, 1941).

There are approximately 13 600 named species of ferns and lycophytes globally (Hassler and Swale, 2001; Chapter 14). Because new species continue to be described and because of persistent regional gaps in floristic treatments, the real number of fern and lycophyte species is not yet known. Due to declining abundance or local extirpation, fern and lycophyte species of conservation concern have been identified for certain areas and have become the focus of international conservation efforts. Conservation biology research today is acting in response to environmental degradation across the globe, with increased human impacts to vulnerable ecosystems causing alarming rates of species extinction and habitat loss. Early accounts of conservation threats to fern species in the USA were

Biology and Evolution of Ferns and Lycophytes, ed. Tom A. Ranker and Christopher H. Haufler. Published by Cambridge University Press. © Cambridge University Press 2008.

attributed to habitat destruction and over-collection by fern enthusiasts and commercial horticulturalists (Overacker, 1930). As early as 1912, "a plea for fern conservation" was published in the American Fern Journal, lamenting the over-harvesting of local fern species to be shipped to florists (Phelps, 1912). In 1929 the American Fern Journal published an editorial concerning the preservation of ferns in the area of Staffordshire, England: donations of rare and native ferns were requested to supplement the new "fern sanctuary," not to the detriment of wild-collected ferns but rather "extra garden specimens" from private holdings (Anonymous, 1929). The New York "state fern law," as it was called, was passed in 1930 as an amendment to the State Conservation Law, which legislated it a misdemeanor to possess whole or part of the hart's tongue fern, Scolopendrium vulgare (Overacker, 1930). These early efforts to protect various fern species from local extinction have continued into the present, with conservation biologists rising to the challenge of safeguarding biodiversity and the ecosystem processes that sustain it.

This chapter reviews published research within the context of the multidimensional strategies of fern and lycophyte conservation biology. These are exciting times, as research continues to evolve with new approaches to tackle difficult conservation problems. Section 10.2 will describe some of the reasons why ferns and lycophytes are important subjects of conservation efforts. Section 10.3 will expand on the threats to global diversity of ferns and lycophytes. Section 10.4 will summarize published research and conservation implications of the fern and lycophyte life cycle relative to seed plants. Section 10.5 will discuss ex situ propagation for conservation. Sections 10.6 and 10.7 will describe geographical regions and ecosystems of concern for ferns and lycophytes, and the specific groups and species of ferns and lycophytes at risk. Section 10.8 will explain the usefulness and growing field of conservation genetics, and Section 10.9 will summarize published research on habitat restoration methods to conserve fern and lycophyte diversity. A concluding section will contain recommendations for future research and action.

10.2 Conservation importance of ferns and lycophytes

Ferns and lycophytes are ancient and diverse lineages with global distribution, yet many taxa are restricted to certain habitats (Given, 2002). The majority of fern and lycophyte species are found in the tropics (Gomez-P., 1985), and often comprise a significant portion of the vascular plant flora in tropical regions. With new fern and lycophyte species still being discovered, as in the case of the newly described Ctenitis bigarellae from Paran√°, Brazil (Schwartzburd et al., 2007), and their high diversity in the tropical and temperate rainforests, ferns and lycophytes are considered extremely vulnerable to extinction. At the current rate of habitat fragmentation and deforestation of temperate and tropical rainforests, and given the specialized ecological niches that fern and lycophyte species require (e.g., see Chapter 8), it is likely that many species will go extinct before they have been described.

On remote oceanic islands of the tropics and subtropics, ferns and lycophytes comprise a larger proportion of the flora than is typically found in continental regions with similar environmental conditions (Kramer, 1993). Given (1993) stated that, "the relatively large contribution by pteridophytes to the vegetation of many oceanic islands has important consequences for conservation priorities," (p. 295). Indeed, ferns and lycophytes may be considered habitat enhancers for other plant and animal species, in relationships that are currently under investigation. For example, mature forest canopy species of epiphytic ferns provide necessary foraging habitat for endemic avian communities in the Udzungwa Mountains of Tanzania (Fjeldsa, 1999), and sooty owls were more often found in wetter senescent forest associated with the tree ferns Cyathea australis and Dicksonia antarctica in northeast Victoria, Australia (Loyn et al., 2001). Moran et al. (2003) found that tree fern trunks at several sites in Costa Rica supported a greater diversity of fern epiphytic species than did the trunks of neighboring woody angiosperms, with seven of 11 species of epiphytes restricted to tree-fern trunks and none restricted to angiosperm trunks. During winter and spring, the Azores bullfinch Pyrrhula murina feeds on fern sporangia and fern fronds (Ramos, 1995), and species of Drosophila in Australia use tree fern fronds within the forest interior as important microhabitat sites, due to the cooler temperatures, higher humidity, and a constant thick layer of rotting leaf litter under the interior forest tree ferns (Parsons, 1991). The rusty-winged barbtail (Premnornis guttuligera) builds its nest entirely out of the petiole scales of a species of Cyathea (Dobbs et al., 2003). Evidence from coprolites suggests that the diet of the extinct, flightless moa-nalo bird (Thambetochen chauliodous) of the Hawaiian Islands may have specialized on ferns (James and Burney, 1997).

Humans have long used ferns and lycophytes for medicinal and spiritual purposes. Ethnobotanical studies have documented several species of ferns and lycophytes that are used for treating ailments and illnesses, and in various traditional rituals and ceremonies (e.g., see Manandhar, 1995; Samant et al., 1998; Macia, 2004 and references therein). Macia (2004) recorded the use of 24 species of ferns in two groups of Amerindians from Amazonian Bolivia and Ecuador, mostly for medicinal purposes. Plant geneticists and cytogeneticists have measured mutation rates of fern rhizomes in healthy and polluted ecosystems to detect and screen environmental carcinogenesis caused by toxins in air, water, soil, food, and even manufactured products (Klekowski and Poppel, 1976). For example, a population of Osmunda regalis was documented to have a higher incidence of post-zygotic mutational damage in a river heavily polluted with wastes from paper processing compared to populations growing in unpolluted rivers (Klekowski, 1978). Fern bioassays can detect chronic low-dose and episodic high-dose inputs of mutagenic pollutants in aquatic ecosystems (e.g., see Klekowski, 1976, 1978, 1982; Klekowski and Berger, 1976; Klekowski and Levin, 1979; Klekowski and Klekowski, 1982). Ferns have even been discussed in the context of ''untapped biodiversity," because the novel extreme environmental adaptations of ferns, including heavy metal tolerance and hyperaccumulation, could be developed as genetic resources to aid the development of stress tolerance in commercial crops (Rathinasabapathi, 2006). One such fern, Athyrium yokoscense, was highly tolerant to lead toxicity, and gametophytes accumulated lead and localized it in the cytosol and vacuole of rhizoidal cells (Kamachi et al., 2005). These studies in the detection of environmental toxicity using ferns are especially relevant today as the contamination of soil, water, and air continues with increasing industrialization. They could be useful tools for conservationists and public health officials working to detect and mitigate environmental pollutants.

Ferns and lycophytes are also useful indicators of habitat quality, species diversity, land use types, and disturbance regimes. Because ecological requirements vary across species, their occurrence in certain areas make evident predictable habitat characteristics, such as open disturbed habitat, young secondary forest, or primary forest (Poulsen and Tuomisto, 1996; Tuomisto and Poulsen, 1996; Arens and Baracaldo, 1998; Myster and Sarmiento, 1998; Muller, 2000; Beukema and van Noordwijk, 2004; Banaticla and Buot, 2005). Also, certain fern species are important colonizers in early succession and gaps (Turner et al., 1996; Arens and Baracaldo, 1998; Bey, 2003).

10.3 Threats to global fern and lycophyte diversity

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