The potential of novel native plant materials for the restoration of novel ecosystems

Abstract

Extensive ecological change has been sustained by many dryland ecosystems throughout the world, resulting in conversion to so-called novel ecosystems. It is within such ecological contexts that native plant materials destined for ecological applications must be able to function. In the Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis [Beetle & A.M. Young] S.L. Welsh) ecosystems of the Intermountain West, for example, novel ecosystem structure and functioning are pervasive. Invasive species, particularly annual grasses, fuel repeated wildfires that drive previously stable ecosystem states across thresholds to less desirable states that are highly recalcitrant to restoration efforts. Structural changes include reductions of native flora, damage to biological soil crusts, and alterations to soil microbiota. Functional changes include altered hydrologic and nutrient cycling, leading to permanent losses of soil organic matter and nitrogen that favor the invaders. We argue that there is an important place in restoration for plant materials that are novel and/or non-local that have been developed to be more effective in the novel ecosystems for which they are intended, thus qualifying them as "ecologically appropriate." Such plant materials may be considered as an alternative to natural/local "genetically appropriate" plant materials, which are sometimes deemed best adapted due to vetting by historical evolutionary processes.

Seed production areas for the global restoration challenge

“…Not only are improved varieties often phenotypically invariant (Espeland & Hammond, ; Leger & Baughman, ) and therefore unlikely to respond to selection imposed by climate change and other adaptive hurdles (Espeland et al., ), but they have often been developed specifically for traits such as above‐ground biomass accumulation, herbicide tolerance, or suitability for mechanized harvesting (Chivers, et al and references therein) that may be maladaptive in the long term in some restoration environments (Leger & Baughman, ). Although cultivars and non‐native species might be considered the most cost‐effective and readily available seed varieties when short‐term goals like soil stabilization cannot be achieved with native accessions (D'Antonio & Meyerson, ; Jones, Monaco, & Rigby, ), they cannot be considered a cost‐effective choice when the goal of restoration is to sustain diverse native landscapes and the native wildlife that depend on them (Kuebbing & Nuñez, ). There is little evidence that successful cultivar or non‐native plantings become desirable native plant communities (D'Antonio & Meyerson, ; Kettenring, Mercer, Reinhardt Adams, & Hines, ; Prach & Hobbs, ).…”

Poa secunda local collections and commercial releases: A genotypic evaluation

“…This practice risks negative impacts on population fitness, including inbreeding and outbreeding depression resulting from the introduction of limited diversity or divergent/maladapted genotypes, respectively [30]. At the same time, these risks must be weighed in light of plant communities that have undergone novel anthropogenic alterations and/or invasion by exotic species [31]. …”

The merits of artificial selection for the development of restoration‐ready plant materials of native perennial grasses

“…On the other hand, when artificial selection is performed properly with appropriate safeguards in place (Jones & Robins ), use of this tool may improve the efficacy of a cross‐pollinated native grass population for use in restoration applications. If local plant materials merit a place at the table for restoration of heavily altered novel ecosystems, it would seem that plant materials with improved adaptation under such circumstances would merit consideration as well (Jones et al ). One might be tempted to assume that the restoration‐ready approach and the local approach to plant‐material development are mutually exclusive.…”

“…The need for well‐adapted restoration plant material is paramount, but this is particularly so for challenging environments such as semiarid and arid rangelands. More to the point, the need for novel plant materials that can limit further ecological damage from invasive species, soil degradation, altered fire regimes, and climatic change is great (Jones et al ). This may involve the development and use of materials that are better adapted than local material when the latter fares poorly under modified conditions.…”

“…However, such approaches are based on the uncertain assumption that local is best (Broadhurst et al ; Jones 2013 b ). In addition, populations developed with these approaches may not necessarily be adapted to ecologically modified novel ecosystems that may currently predominate (Jones et al ) or to the cultivated seed‐production environment.…”