A Restoration Practitioner's Guide to the Restoration Gene Pool Concept

THEORY A Restoration Practitioner’s Guide to the Restoration Gene Pool Concept by Thomas A. Jones and Thomas A. Monaco ABSTRACT Choosing plant materials for each desired species is often one of the most difficult steps in developing a restoration plan. The Restoration Gene Pool concept was developed to clarify the options available to the ecological restoration practitioner in terms of plant materials. We present a decision-making flowchart incorporating the issues delineated in the Restora - tion Gene Pool concept. We intend to provide practitioners with a framework to make objective and defensible plant materials choices in keeping with the objectives and philosophy of the restoration project. The flowchart consists of a series of boxes with single or multiple statements to be judged as true or false. The statements deal with issues such as genetic identity, plant metapopulation, functional guild, ecoregion, invasive weed presence, site soil and climate, endangered species presence, commercial seed availability, seed contracting potential, and availability of material bred for improved stress tolerance. Implementing the flowchart is a straightforward way to apply the Restoration Gene Pool concept to a particular project, but we encourage each practitioner to personalize the flowchart to make it as practical as possible for the situations that she or he most often encounters. Keywords: plant materials, genetic identity, metapopulation, ecoregion, Restoration Gene Pool concept, ecological restoration ne of the first steps in form- ers 1997, Brown and Amacher 1999). Brown (2004) makes the case for Oulating an ecological restoration The Restoration Gene Pool (RGP) using the functional guild concept to plan is the development of a plant concept (Jones 2003) assigns plant condense the species list to a reasonable species list. While this is typically materials to one of four restoration number of species that 1) satisfy straightforward, the next step, making gene pools (primary to quaternary) in requirements for ecosystem structure choices among plant materials for a order of declining genetic correspon - and function and 2) deter establish - given species, may be more complex. dence to the target population for the ment of undesirable species. Func- In some cases the desired species may restoration project. In this approach tional guilds are used to condense not be commercially available, while to plant material selection, adapta - species lists into groups consisting of in other cases there may be multiple tion is decoupled from genetic iden - individual species that possess similar plant materials to choose from. In tity because they often do not ecological structure and function still other cases, the only commer - correspond, particularly when the (Walker 1992, Naeem and Wright cially available material of the desired ecosystem function of the disturbed 2003, Brown 2004)—an approach species may be deemed ecologically or site has been irreversibly or signifi - that may be more pragmatic than genetically inappropriate for meeting cantly altered. In such situations, inclusive of every species on the species project objectives. plant material with highest genetic list (Walker 1992). Inclusion of a func - Ecological restoration practitioners identity (the primary restoration gene tional guild may also reduce site vul - have long been faced with a choice pool) may not be successful, in which nerability to invasion by undesirable between native and introduced plant case material from a higher-order pool species of the same functional guild material—a choice confounded by a may be substituted. This decision can (Fargione and others 2003), while general lack of consensus concerning be made individually for each plant inclusion of multiple desirable species what constitutes “being native” (Mil - species in the restored plant commu - of a particular functional guild may lar and Libby 1989, Roundy and oth - nity within the scientific context that increase stability (Chapin and others ecosystem management demands. 1997). Others argue that this may be Ecological Restoration Vol. 25, No. 1, 2007 The RGP concept provides a place for an unrealistic expectation at large scales ISSN 1522-4740 E-ISSN 1543 -4079 cultivars of native species and nonin - (D’Antonio and Meyerson 2002). ©2007 by the Board of Regents of the vasive introduced plant material when Walker (1992) suggests that guilds University of Wisconsin System. use of native material is not feasible. should be subdivided according to 12 March 20 07 ECOLOGICAL RESTORATION 25:1 non-trivial functional attributes until indigenous material, but also because Restoration Gene Pools the remaining species are mostly of the potential for irreversible cont - Primary Restoration Gene Pool redundant. This may largely resolve amination of the local gene pool for the presence of residual functional cross-pollinated species in particular • 1° RGP material may be 1) collected variation among species within func - (Millar and Libby 1989, Knapp and from the restoration site or from a tional guilds as described by Brown Rice 1994). site or bulked across multiple sites (2004). For example, cool-season However, in situations where (metapopulations) that have been grasses could be subdivided according immediate repair of ecosystem func - determined either by presumption to growth habit, phenology, or life tion is deemed more critical than or, preferably, by genetic study to be history. While the functional guild possible long-term consequences of genetically connected to it by gene approach may appear to conflict with compromising species composition, flow (seed and/or pollen transfer) the view that each species is innately the quaternary RGP will be an (Option A); or 2) collected from a important to ecosystem function acceptable alternative (Ewel and site or bulked across multiple sites of (Ehrlich and Ehrlich 1981), Chapin Putz 2004). While acknowledging the same plant community type as and colleagues (1997) point out that the risks of non-native species, these the target site elsewhere in the same this conflict is resolved when each authors argue that greater risk-tak - Level III ecoregion (U.S. Environ - species is interpreted as a member of ing is warranted when environmen - mental Protection Agency 2006) a functional guild. In other words, tal conditions have been severely (Figure 1), but without genetic con - duplication within a functional guild modified by human activity. They nectivity (Option B). is less critical to ecosystem structure believe that introduced species that • Material is “natural” rather than and function than having a single provide essential ecological or socio- “genetically manipulated” (subjected representative of each functional economic services may be used to to selection and/or hybridization) guild present. good advantage. They acknowledge and may be certified as “source-iden - The RGP concept (Jones 2003) that, in some cases, these needs are tified” pre-variety germplasm (PVG) provides a framework for clarifying better met by introduced species (Figure 2; Jones and Young 2005). the issues involved in choosing plant than native species. materials for each species itemized in If an introduced species is to be While the practitioner’s typical pre - a condensed species list developed used, it should be well established ferred alternative is to use material using functional guilds. The purpose that it has no invasive properties. indigenous to the site (Option A), of the RGP descriptor (1°, 2°, 3°, 4°) Ewel and Putz (2004) note that some contract seed production is not always is to succinctly describe the rela- non-native species are relatively feasible because of expense or the pro - tionship between the target plant innocuous, whereas others have dra - ject’s scheduled time frame. Seed costs population and the restoration plant matic negative effects on ecosystem may be high because demand for such material. Each pool is briefly de- structure and function. They material may be limited beyond the scribed below, but we refer the reader addressed the risks of species intro - restoration project. Costs might be to an earlier publication (Jones 2003) duction by making several sugges - more reasonable if there were suffi - for a more thorough discussion. tions for assessing a species’ potential cient commercial demand for the We recognize that the four pools invasiveness. The subject of predict - product such that it could become are unlikely to have equal merit in ing potential for invasiveness has part of the business’ product line. the eyes of the ecological restoration been addressed by numerous invasive When Option A is not feasible, the practitioner. Nevertheless, we in- species biologists (Mack 1996, practitioner should investigate Option clude all of them here for the sake of Goodwin and others 1999, Kolar B, material of the same metapopula - completeness. Many practitioners and Lodge 2001, Hegen and Trepl tion as determined by a genetic study. will prefer strict use of the primary 2003, Sutherland 2004). Neverthe - Material from the same plant commu - RGP (indigenous material), while less, many restoration ecologists and nity type, for example, Shiflet’s (1994) others will tolerate the use of the practitioners will find the use of rangeland cover types, elsewhere in quaternary RGP (vicarious, non- introduced species under the moni- the Level III ecoregion (U.S. Environ - native species). Besides personal pref - ker of restoration inappropriate, pre - mental Protection

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