Them's the Brakes

Abstract

Large nearly monoculture stands of Arundinaria, called canebrakes, historically covered millions of acres in the southeastern United States (Platt and Brantley 1997). This ecosystem was vital to wildlife and played a pivotal role in lowland ecosystem functions and the cultural history of native American tribes (e.g., Cherokee and Choctaw). Canebrake decline started around the time of European settlement, mainly due to altered disturbance regimes (fire and flood), overgrazing, clearing for agriculture, and forest canopy closure. Today, canebrakes are regarded as one of United States’ most critically endangered natural plant communities (Noss et al. 1995), covering less than two percent of their former extent. Remnant stands are highly fragmented as well, with expansive canebrakes non-existent. Growing evidence suggests the loss of canebrakes has directly impacted many riparian ecosystems resulting in increased soil erosion, poorer water quality, and decreased flood control (Schoonover and Willard 2003), as well as the extirpation (and perhaps the extinction) of many species (Brantley and Platt 2001). Although interest in canebrake restoration and conservation for wildlife has been expressed by a number of conservation committees and land stewardship agencies, the amount of information about the biology and genetics of canebrakes and resources (e.g., propagation materials) necessary to support large restoration activities is scant. This is partly due to the unusual life cycle of bamboo. Arundinaria is clonal, sending out rhizomes that develop into new culms (ramets); such clones may be expansive in size. Arundinaria is also monocarpic, flowering once every 25–30 yr (hence, a seed source is not available to generate propagules) and subsequently the whole individual (genet) dies. Death may occur over fairly broad areas due to the long period of pre-flowering clonal growth. While small restoration trials and propagation studies have provided some information, further studies are needed if large restoration activities are to be completed successfully. To that end, a symposium was developed in the spring of 2008 at the annual Association of Southeastern Biologists conference to: 1) bring together scientists studying everything from taxonomy to micropropagation, 2) give stateof-the-art knowledge on restoration and propagation techniques, and 3) develop future research needs for Arundinaria species (Franklin et al. 2008). The following papers represent selected works from the speakers at that symposium, and fall under four major themes: 1) phylogeny and population genetics, 2) autecology, 3) ecosystem services, and 4) restoration. The taxonomy of Arundinaria in North America has gone through a variety of changes, but only recently have molecular techniques been used to determine with more certainty the phylogenetic relationships of genus Arundinaria. Triplett and Clark summarize morphological diagnostics as well as molecular results for distinguishing the three species of this North American endemic genus and provide two epitypes for clarification. Long-lived semelparous plants like cane add a further difficulty to understanding population interactions. Knowledge of genetic diversity within and among clonal stands is important for maintaining genetic diversity in restoration efforts and understanding fertilization potential of a known outbreeder. Mathews et al. examine the genetics between and within stands of cane, including flowering stands, to examine the extent of genetic diversity in canebrakes. Due to the extensive loss of canebrakes, it is difficult to know the autecology of the species simply from field studies. A review of historical accounts, together with records of present day distribution and manipulative studies of * email address: Scott.Franklin@unco.edu CASTANEA 74(3): 205–206. SEPTEMBER 2009