Opportunities, research gaps, and risks in allogenic ecosystem engineer mimicry

Abstract

In an age of anthropogenically driven species loss and increasingly novel ecosystems, ecosystem engineer restoration is a process-based approach to supporting ecosystem function. Many ecosystem engineers have low or declining population sizes. When feasibility and costs impede reintroduction of ecosystem engineers, an alternative may be artificial mimicry of ecosystem engineer structures. Research on mimicry of autogenetic ecosystem engineers, whose physical structure shapes habitat availability and complexity (e.g., tropical corals whose hard skeletons create complex reefs that provide habitat), spans many process scales. However, mimicry of allogenic ecosystem engineers, which shape habitat availability through their behavior (e.g., beavers building dams that influence hydrology), is less well explored. We reviewed the literature to examine the efficacy of artificial mimicry of allogenic ecosystem engineers and gaps in the research. Emerging findings suggest that artificial mimicry could restore physical processes, support focal species, alter biological communities, deliver benefits to landowners and ecosystems, and promote population recovery. However, some studies document the potential for unintended negative consequences for ecosystem engineers or species that use engineered structures or respond to environmental cues produced by engineered structures. Topics requiring additional research include assessing the efficacy of artificial structures as compared with natural structures, evaluating the scalability and cost-effectiveness of mimicry projects, and investigating the potential for unintended consequences with mimicked structures.

Keywords: allogenic ecosystem engineers; artificial mimicry; ecosistemas alógenos; ecosistemas novedosos; evolutionary traps; ingeniería de ecosistemas; mimetismo artificial; novel ecosystems; restauración; restoration; trampas evolutivas; 人工模拟; 外源生态系统工程师; 恢复; 新型生态系统; 演化陷阱.

FIGURE 1

Comparison of existing research on natural and mimicked allogenic and autogenic engineer structures in a variety of research areas (spatial structure or design, research on effects of the physical shape, distribution, or construction materials of the natural or artificial structure; physical process, research on the effect of structures on physical processes; population effects, research on density of organisms, habitat or refuge creation for organisms, or primary production; community effects, research on community metrics, such as diversity, community composition, and colonization rates; ecosystem services, research on ecosystem processes, e.g., nutrient cycling and litter decomposition, and services, e.g., groundwater recharge, shoreline protection, ecotourism; EU, experimental use of an artificial structure rather than studies on artificial structures used in a restoration capacity; dark green shading indicates a research area with at least 3 studies on 3 different topics under that research area, light green shading indicates that one of these criteria were not met, yellow shading indicates that both of these criteria were not met). To illustrate the extent of research for each of allogenic and autogenic engineers, for each engineer type we choose three examples that differ in their habitat types (e.g., in terms of terrestrial vs. aquatic from freshwater to estuarine to marine, or tropical to temperate) and types of engineering functions. References: ¹(Übernickel et al. 2021); ²(Yoshihara et al. 2010); ³(Machicote et al. 2004); ⁴(Platt et al. 2016); ⁵(Bowker et al. 2013); ⁶(Beca et al. 2022); ⁷(Fleming et al. 2014); ⁸(Linley et al. 2024); ⁹(Pike and Mitchell 2013); ¹⁰(Galvez Bravo et al. 2009); ¹¹(Mallen‐Cooper et al. 2019); ¹²(Davidson and Lightfoot 2008); ¹³(Riding and Belthoff 2015); ¹⁴(Keppers et al. 2008); ¹⁵(Ebrahimi et al. 2012); ¹⁶(Nadeau et al. 2015); ¹⁷(Fromant and Bost 2020); ¹⁸(Wilson 1986); ¹⁹(Bourgeois et al. 2015); ²⁰(Smith et al. 2005); ²¹(Grillet et al. 2010); ²²(Souter et al. 2004); ²³(Mosepele et al. 2009); ²⁴(Kerley and Landman 2006); ²⁵(Valeix et al. 2011); ²⁶(Pringle 2008); ²⁷(Coverdale et al. 2016); ²⁸(Poulsen et al. 2017); ²⁹(Stommel et al. 2016); ³⁰(McComb et al. 1990); ³¹(Swinnen et al. 2019); ³²(Ronnquist 2021); ³³(Brazier et al. 2021); ³⁴(Larsen et al. 2021); ³⁵(Romansic et al. 2021); ³⁶(Fairfax and Whittle 2020); ³⁷(Wade et al. 2020); ³⁸(Munir and Westbrook 2021); ³⁹(Corline et al. 2023); ⁴⁰(Weber et al. 2017); ⁴¹(Bouwes et al. 2018); ⁴²(Orr et al. 2020); ⁴³(Pollock et al. 2014); ⁴⁴(Graham and Nash 2013); ⁴⁵(Komyakova et al. 2013); ⁴⁶(Escudero et al. 2021); ⁴⁷(Oberdorfer and Buddemeier 1986); ⁴⁸(Storlazzi et al. 2004); ⁴⁹(Storlazzi et al. 2009); ⁵⁰(Davis et al. 2011); ⁵¹(Wild et al. 2004); ⁵²(Brooks et al. 2007); ⁵³(Coker et al. 2014); ⁵⁴(Rädecker et al. 2015); ⁵⁵(Komyakova et al. 2019); ⁵⁶(Perkol‐Finkel et al. 2006); ⁵⁷(Walsh 1985); ⁵⁸(Ambrose 1994); ⁵⁹(Sherman et al. 2002); ⁶⁰(Charbonnel et al. 2002); ⁶¹(Dewsbury and Fourqurean 2010); ⁶²(Ambrose and Anderson 1990); ⁶³(Falcão et al. 2009); ⁶⁴(Andskog et al. 2023); ⁶⁵(Ng et al. 2017); ⁶⁶(Fabi et al. 2002); ⁶⁷(Baynes and M. Szmant 1989); ⁶⁸(Kim et al. 2020); ⁶⁹(Belhassen et al. 2017); ⁷⁰(Tynyakov et al. 2017); ⁷¹(Peterson et al. 2004); ⁷²(Chen et al. 2007); ⁷³(Christianen et al. 2013); ⁷⁴(Hovel et al. 2002); ⁷⁵(Bowden et al. 2001); ⁷⁶(Bell et al. 1988); ⁷⁷(Bos et al. 2007); ⁷⁸(van Katwijk et al. 2010); ⁷⁹(Prasad et al. 2019); ⁸⁰(Healey and Hovel 2004); ⁸¹(Bologna and Heck 2000); ⁸²(Upston and Booth 2003); ⁸³(Ambo‐Rappe and Rani 2018); ⁸⁴(Villanueva et al. 2023); ⁸⁵(Carus et al. 2022); ⁸⁶(Layman et al. 2016); ⁸⁷(Virnstein and Curran 1986); ⁸⁸(Nakamura et al. 2007); ⁸⁹(Bartholomew 2002); ⁹⁰(Shahbudin et al. 2011); ⁹¹Marin‐Diaz et al. (2021); ⁹²(John et al. 2016); ⁹³(Griffitt et al. 1999); ⁹⁴(Roncolato et al. 2024); ⁹⁵(Grabowski and Peterson 2007); ⁹⁶(Reidenbach et al. 2013); ⁹⁷(Pfirrmann and Seitz 2019); ⁹⁸(Posey et al. 1999); ⁹⁹(Lenihan 1999); ¹⁰⁰(Walles et al. 2016); ¹⁰¹(Goelz et al. 2020); ¹⁰²(Hogan and Reidenbach 2022); ¹⁰³(Soniat et al. 2004); ¹⁰⁴(Furlong 2012); ¹⁰⁵(Cannon et al. 2022); ¹⁰⁶(Smith et al. 2023); ¹⁰⁷(Brown et al. 2014); ¹⁰⁸(Hammond et al. 2020); ¹⁰⁹(Pierson and Eggleston 2014); ¹¹⁰(Wellman et al. 2022).

FIGURE 2

Examples of artificial allogenic ecosystem engineer structures: (a) beaver dam analogs on Sugar Creek, Scott Valley, California (photo by an author), (b) nesting box on the Putah Creek nest box highway (photo from UC Davis Museum of Wildlife and Fish Biology Putah Creek Nest Box Highway Program), and (c) burrowing owl emerging from an artificial burrow (photo from Adobe stock). These structures can range in the naturalness of the construction materials, with the examples shown ranging from the most natural to the least natural from left to right.