In press, 2nd Interface Between Ecology and Land Development in California J.E. Keeley, Coordinator. Occidental College, April 18-19, 1997. On the Perils of Ecological Restoration: Lessons fr om the El Segundo Blue Butterfly
Travis Longcore,1 Rudi Mattoni,1 Gordon Pratt,2 and Catherine Rich1
1Urban Wildlands Group, UCLA Department of Geography, Los Angeles, CA 90095 2Department of Entomology, University of California, Riverside, CA 92521
Abstract . Land use planning and permitting in vegetation in an area (unpublished data and Califor- southern California increasingly relies on ecologi- nia Ecological Restoration Projects Inventory 1997). cal restoration as mitigation for damage done to If historic conditions are not the goal, as they rarely natural habitats by development projects. Many restoration attempts fail miserably, for a number are, the question arises whether restoration is under- of reasons. Three areas of concern for restoration taken to reassemble the species and ecotypes histori- projects are: 1) historical accuracy and complete- cally present or to use different species that the restor- ness, 2) ecotype accuracy, and 3) type conver- ationist believes will serve the same function in the sions. Using evidence from a restoration project ecosystem. The distinction here is made between a for the El Segundo blue butterfly we will show the concentration on diversity or function. Jordan et al. importance of historical accuracy in ecological (1987) suggest that restorationists can illustrate their restoration. Other examples from the El Segundo understanding of ecosystems by imitating rather than dunes will illustrate the vital importance of using copying natural systems. They claim that insight from local ecotypes in restoration projects. Finally, we restoration research will be gained from being able will discuss the issues raised by type conversions to “create communities that resemble other commu- and other questionable restoration practices, why they are allowed as mitigation, and their effect on nities in various ways, but that actually differ from them regional conservation goals. in species composition” (Jordan et al. 1987: 17). We differ from Jordan et al. about the goals of restoration Keywords : Restoration; mitigation; historical ac- and restoration research. For reasons that will be il- curacy; ecotype accuracy; type conversion; El lustrated below, we believe that restoration should Segundo blue butterfly have as its goal the preservation of biodiversity in a system that requires minimal human management INTRODUCTION and that is historically accurate and historically com- Ecological restoration is used as a mitigation for plete. To qualify as a “restoration” a project should damage done to natural habitats and species by de- strive to be historically complete and accurate and velopment projects. Although such restoration pro- consider the reintroduction or management of all jects take place under the auspices of public agencies biodiversity, including insects, mammals, birds, plants, such as the U.S. Army Corps of Engineers, the U.S. and cryptobiotic crusts. A project that reintroduces the Fish and Wildlife Service, the California Coastal Com- historically present plants is a “revegetation,” a project mission, and the California Department of Fish and that only establishes the dominant cover is a “partial Game, they often are plagued by weaknesses that go revegetation,” and any project that establishes species largely unnoticed or unquestioned by environmental not native to the site is an exercise in “landscaping.” activists, the academic community, politicians, and the A second aspect of the definition of restoration is agencies themselves. Drawing from experience with what has been called “the ecotype question” (Cairns a revegetation project for the El Segundo blue butter- 1987: 316, Kline and Howell 1987: 84). Debate cen- fly, we explore some of the common pitfalls of resto- ters around the relative importance of matching lo- ration projects. cal ecotypes when reestablishing plants on a restora- Any discussion of restoration requires an under- tion site. Although academic consensus seems to sup- standing of what is meant by the word. The definition port using local ecotypes (see Millar and Libby 1989, arrived upon by a National Research Council commit- Read et al. 1996, Allen 1997), we illustrate the impor- tee was “the return of an ecosystem to a close approxi- tance of local ecotypes on higher trophic levels and mation of its condition prior to disturbance” (NRC the maintenance of biodiversity. A project that does 1992). Unfortunately, mitigation almost never has re- not use local ecotypes is not a “restoration.” creation of the historic conditions as its goal, rather, The final facet of restoration that we discuss is success is defined as establishment of the dominant whether type conversion — the creation of one natu- 1400 4000 1200 3500 1000 Site 3 3000 800 Site 2 2500
600 Site 1 2000 400 1500 200 1000
Microlepidopterous Larvae/50 cc flowers 0 500 Estimated ESB Population Size 0 1986 1987 1988 1989 1990 1991 1992 1993 Sep 3, 85 Jul 16, 85 Jul 19, 85 Jul 23, 85 Jul 25, 85 Jul 30, 85 Aug 3, 85 Aug 6, 85 Aug 10, 85 Aug 14, 85 Aug 15, 85 Aug 21, 85 Aug 25, 85 Aug 27, 85 Aug 20, 86
Fig. 1. Abundance of larval microlepidopterous competi- Fig. 3. Recovery of ESB population following removal of tors of the ESB (Gelechiidae and Cochylidae) on Eriogonum fasciculatum and provision of more Eriogonum parvifolium at three sites at LAX (Pratt foodplant (Mattoni et al., in prep.). 1987).
30 1975 the backdune at LAX was recontoured to realign 25 Pershing Drive. The recontoured backdunes were sta- 20 Site 3 bilized with a “natural” seed mix (Mattoni 1989a). 15 Site 2 Although perhaps well intentioned, the seed mix was 10 representative of coastal sage scrub, not the native Site 1 5 dune scrub community. Whether this effort was meant ESB Larvae/50 cc flowers 0 as a restoration is irrelevant, the event of interest is that common buckwheat (Eriogonum fasciculatum (Benth.) Torrey & A. Gray) was introduced and estab- Sep 3, 85 Jul 16, 85 Jul 19, 85 Jul 23, 85 Jul 25, 85 Jul 30, 85 Aug 3, 85 Aug 6, 85 Aug 10, 85 Aug 14, 85 Aug 15, 85 Aug 21, 85 Aug 25, 85 Aug 27, 85 Aug 20, 86 lished on the dunes.1 Numerous other insects exploit Eriogonum flower- Fig. 2. Abundance of ESB larvae on Eriogonum parvi- folium at three sites at LAX (Pratt 1987). heads, which results in intense competition for the resource. This guild of competitors includes at least ral community in an area that was previously occupied ten species of Lepidoptera in addition to an unknown by another natural community — constitutes restora- number of other orders. While the ESB is univoltine tion. Examples of this specific kind of historical inac- (one generation per year) and is specialized for the curacy abound, especially for wetland and riparian short, late blooming season of E. parvifolium, other restoration projects (Allen and Feddema 1996). We competitors are more opportunistic and will utilize argue that ecological restoration does not include type multiple hosts. The introduction of the earlier bloom- conversions. ing E. fasciculatum to the dunes therefore had the re- sult of differentially increasing populations of competi- HISTORICAL ACCURACY AND COMPLETENESS tors by providing another food source that the ESB A story illustrates the dangers of historical inaccu- could not exploit. Pratt (1987) showed that there was racy. The El Segundo blue butterfly (Euphilotes bern- a doubling of competitive larvae on E. parvifolium ardino allyni Shields) (ESB) was distributed historically flowerheads in mid-August, which, considering an along the El Segundo dunes from Ballona Creek to average generation time of one month, corresponded the Palos Verdes Peninsula (Mattoni 1992). Its sole with senescence of E. fasciculatum in mid-July. In- foodplant for all life stages is the coastal buckwheat, creased concentrations of other larvae correlated with Eriogonum parvifolium Smith. Larvae feed on the depressed ESB populations. Experiments confirmed flowerheads, pupate directly beneath the plant, and that other microlepidopterous larvae outcompete and adults perch, mate, usually nectar, lay eggs, and prob- even cannibalize ESB larvae. In addition, the other ably die on flowerheads (Mattoni 1992). moths probably provide a reserve of parasitoids that The ESB persists in greatest numbers on the dunes they share with the ESB (Pratt 1987, Mattoni 1988). at the Los Angeles International Airport (LAX). In The increase in ESB and decrease in other larvae shown in the 1986 follow-up sample is likely the re- 1 Also present in the seed mix were Coreopsis gigantea (Kellogg) H.M. sult of intense pruning of E. fasciculatum to delay flow- Hall, Atriplex canescens (Pursh) Nutt., Lupinus excubitus M.E. Jones, ering. Eriogonum giganteum S. Watson, E. cinereum Benth., and other non- Mattoni initiated a revegetation program on the native species. Only E. fasciculatum has expanded on the dunes; the LAX dunes in 1986; one of the first actions was the others are gradually disappearing. removal of E. fasciculatum (Mattoni 1989b). Recovery of the ESB over the course of the revegetation pro- attention to local, ecotypical variation. However, some gram is estimated by using a model based on transect writers have addressed the importance of local varia- counts (Mattoni et al., in prep.). Increases in the first tion to the success or failure of restoration projects, two years of the program can largely be attributed calling it “the ecotype question” (Cairns 1987). to removal of E. fasciculatum, because newly estab- Scholarly discussion of the ecotype question gener- lished E. parvifolium had not yet matured. The reso- ally has supported a position of striving for ecotype nating effect of E. fasciculatum on insect community accuracy. McNeilly (1987) discussed the importance composition shows the result of introducing just one of local ecotypes in heavily degraded areas where species that is not native to an area. This observation plants may have adapted to the extreme toxic condi- implies that attention paid to historical distribution tions of a site, stressing the continuing evolution of of species is a crucial first step to ensure the ecologi- plant populations subject to contaminated conditions. cal integrity of restoration projects. Millar and Libby (1989) explored how to maintain a Another implication of this example, gained from commitment to genetic purity while settling for some- recognizing the far-reaching effects of just one spe- thing less. They note that genetic variation does not cies on natural community composition, is that res- necessarily correspond to geographic variation and toration should also strive to be historically complete. that one must also consider the microclimatic and Although moths and butterflies are rarely target spe- edaphic conditions of individuals used for propagules. cies for restoration projects, and almost never con- Proximity does not necessarily denote the appropri- sidered in mitigation design, many depend on a ate ecotype for a restoration site. Read et al. (1996) single host plant species. Furthermore, butterflies note that the internal variation of some species (e.g., often depend on the rare species in a community, E. fasciculatum) is much greater than others (e.g., Stipa which are often overlooked in restoration efforts. spp.) allowing the restorationist to make judgments The notion of the importance of a single species on about the necessity for site fidelity on a case-by-case the ecosystem is not new; Paine’s (1969) metaphor basis. of the “keystone species” was intended, in his words, Although the consensus seems to be that the restora- “to convey a sense of nature’s dynamic fragility and tionist should only collect propagules based on par- the unsuspected consequences of removing (or add- ticular knowledge of the plants and locations involved, ing) species” (Paine 1995). Omission of one plant spe- this precept is motivated by concern that plants them- cies can result in a significantly impoverished restoration. selves will survive and are genetically appropriate. A second motivation for historical completeness in However, a restoration is not successful if the plants kill restoration projects is that speciose systems are more the organisms that depend on them. While a plant of a non- stable with respect to environmental factors (Putnam local ecotype may survive when planted as part of a 1994:145–147). Walker has termed the existence of revegetation project, consideration rarely is given to many species that serve similar ecological roles “eco- the effects of the plant on other trophic levels. Insects, logical redundance” (Walker 1992; Lawton and especially larval forms, give a rough indication of the Brown 1996). “Redundance” is not meant in a pejo- divergence of different ecotypes. rative sense, but instead illustrates the importance of Consider Eriogonum fasciculatum, which is a food- similar species being able to compensate function- plant for a large number of insects and is widely used ally (e.g., fixing nitrogen) when another species in restoration efforts. We have observed that E. fascic- population has declined (Walker 1995). Ecosystems ulatum shows large geographic variation, which often (and restoration projects) lacking the ecological re- is overlooked in restoration efforts. We know of two dundance that characterized the historic condition restoration sites where a non-local ecotype was estab- will be more susceptible to collapse. lished as part of a restoration project (the Defense Fuel Support Point in San Pedro, and upper Newport ECOTYPE ACCURACY Bay). At the Defense Fuel Support Point we do not The biological species concept (Mayr 1942) is in- know the source of the non-native ecotype, but it is adequate for restoration purposes; rather attention visibly different from nearby local individuals and is must be given to local genetic variation in organisms characterized by a depauperate insect fauna, lacking known as “ecotypes” (Turesson 1922; Clausen et al. many common species found nearby on the local 1948). In a discussion of conservation biology, Rojas ecotype. A few examples of the variation within E. (1992) writes that, “Considering species as typologi- fasciculatum involve rearing lepidoptera larvae for re- cal entities may … lead workers to disregard geo- search purposes. We found a larva of Hemileuca electra graphic variation and to neglect the problem of de- (a saturniid moth) on Eriogonum fasciculatum near ciding which level of variability to protect.” Rojas con- Jacumba, CA. It died after being moved to the San cludes that conservation biologists have neglected to Pedro ecotype (Longcore and J. George, unpublished understand species concepts relative to their work. data). Several larvae of Schinia sp. collected in River- We find that applied restorationists also pay too little side County on Chaenactis glabriuscula DC. died at once after consuming the ecotype from the El Segundo lish a prairie as the understory of oak savanna in the sand dunes (Mattoni, unpublished data).2 To borrow first place. Because of incomplete historical research, a pun from tropical butterfly ecologist Phil DeVries, many restorations performed as mitigations may in- using the wrong ecotype “add[s] insult to herbivory” deed be characterized by a such unintentional type (DeVries and Baker 1989). conversions. Research in the late 1960s and early 1970s by Paul Similar examples can be found in southern Califor- Ehrlich and colleagues (Breedlove and Ehrlich 1968, nia in a number of areas. Unfortunately, would-be 1972, Dolinger et al. 1973) explains the sensitivity of restorationists obliterate the natural community in herbivorous larvae to this intraspecific variation. They their attempts to establish the wrong vegetation type. found that lupine species (Lupinus spp.) subject to For example, because of an error misinterpreting the herbivory by a lycaenid butterfly (Glaucopsyche lyg- extent of the El Segundo dunes (Arnold 1983:80, damus) showed higher levels and compositional vari- 1990:36; see Mattoni 1992:280 for details), some res- ability of alkaloids, compounds that serve as chemical toration attempts have tried to establish dune scrub defenses against the larvae. Further, they discovered vegetation in areas that were historically occupied by that variation in alkaloid content and composition the distinct Los Angeles coastal prairie (Mattoni et al. between lupine populations of the same species was 1997). It was only through close observation and his- often higher than the variation between populations of torical research completed as part of the El Segundo different species. Their work clearly shows the localized dunes restoration that the prairie was recognized and nature of the interrelationships between species (in described. We hope that the recognition and descrip- this instance a plant-herbivore complex). For the tion of the prairie will inform future restoration efforts restorationinst, Ehrlich’s work illustrates the enor- on the remaining fragments. mous importance of ecotype fidelity on the potential The most well documented instances of type con- ecological function of a restoration site. With the ex- versions have been done as mitigation under Section ception of species whose genotypic and phenotypic 404 permits for the Clean Water Act administered by variation are thoroughly explicated with respect to the U.S. Army Corps of Engineers (Allen & Feddema their associated herbivores, local ecotypes should be 1996). In a survey of 75 project sites, Allen and used in restoration. Feddema found that only 67% of the projects had been “successfully completed.” Further, they found an TYPE CONVERSIONS overall decrease in wetlands with some types gaining Finally, we consider habitat type conversions, where- (riparian woodland) while other types declined (fresh- in the restorationist purposefully establishes one habi- water wetland). Distribution of wetland types and over- tat type or vegetation association where it was not all regional wetland location was changed through the found historically. Such intentional or inadvertent mitigation process. Zedler (1996) also documents and type conversions constitute a particularly insidious discusses the need for a regional plan to avoid con- form of historical inaccuracy. Historical accuracy is a tinued replacement of the historic extent of one type difficult goal for restorationists because often little in- of habitat (salt marsh and intertidal flats) with another formation is available in an accessible format. Jordan (deepwater habitat), fueled by mitigation needs. and Packard (1987) describe trial-and-error efforts to Conservation and Policy Implications identify native plant species that would persist under Our work with the El Segundo blue butterfly created oaks near Chicago. Early efforts had attempted to es- the opportunity to learn what can go wrong in an eco- tablish prairie species under the oaks, but further ex- logical restoration project. The mistakes identified perimentation revealed that another distinct set of here occur on a regular basis in projects identified as plants was adapted to such conditions. After discover- “restorations.” These projects, even when developed ing this fact, Packard happened across an 1846 jour- under the supervision of the U.S. Fish and Wildlife nal called The Prairie Farmer, which had identified 108 Service, the California Department of Fish and Game, species characteristic of “barrens,” the settler term for the California Coastal Commission, or the U.S. Army natural oak savanna. While Packard was pleased to Corps of Engineers frequently are historically inaccu- note that those species corresponded with his list of rate and incomplete, and pay little or no attention to savanna species, complete historical research could ecotype accuracy or type conversions. Examples have avoided the frustration of attempting to estab- abound: the plan written for the Deane Dana Nature Center in Friendship Park in Palos Verdes proposes to restore coastal sage scrub with a plant list of about 2 These examples are illustrative only; many other factors may have a dozen shrubs (out of approximately 150 plant spe- caused the deaths of the larvae in question, including stress, bac- cies that can be identified for the site, many of which teria, fungi, and viruses. Also, geographic variation between plant are no longer found in adjacent areas and will never individuals may not be genetic, it may result from environmental recolonize naturally); the Ballona Lagoon “restora- factors such as differing concentrations of heavy metals in the soil. tion” project commenced by bulldozing all vegetation (including natives) leaving no chance for ecotype ac- gered wildlife and habitats in southern California. curacy; the Ballona Wetlands plan developed for the Memoirs of the Natural History Foundation of Orange Playa Vista project converts historic salt marsh into a County, Volume 3. Newport Beach: Natural History sediment detention basin surrounded by landscaping Foundation of Orange County. with native plants bearing little resemblance to the Breedlove, D.E., and P.R. Ehrlich. 1968. Plant-herbivore coevolution: Lupines and Lycaenids. Science 162:671– historic community found on the site (in addition to 672. other marine community conversions, historical inac- Breedlove, D.E., and P.R. Ehrlich. 1972. Coevolution: curacies, and incompleteness). patterns of legume predation by a Lycaenid butterfly. Such ecologically deficient “restoration” projects Oecologia (Berl.) 10:99–104. could simply be avoided through better communica- Cairns, John, Jr. 1987. Disturbed ecosystems as opportun- tion from the academic community to the resource ities for research in restoration ecology. Pp. 307–320 in agencies. Rather than relying entirely on their own Jordan, William R., III, Michael E. Gilpin, and John D. overworked staffs, agencies should solicit peer review Abler, eds. Restoration ecology: a synthetic approach to for restoration plans from qualified experts in the ecological research. Cambridge University Press, Cam- habitats in question who are free from conflicts of in- bridge. terest. Consultants proposing to design and imple- California Ecological Restoration Projects Inventory. 1997. California State Department of Conservation, University ment restoration projects should be required to pass of California at Davis, Society for Ecological Restoration, examinations indicating field identification skills and California (SERCAL), and U.S. Environmental Pro- historical knowledge of the habitats they profess to tection Agency.