Evaluating outcomes of restoration ecology projects on limited budgets: assessment of variation in sampling intensity and sampling frequency for four habitat types

Abstract

While best practices for evaluating restoration ecology projects are emerging rapidly, budget constraints often limit postrestoration monitoring, which emphasizes the need for practical and efficient monitoring strategies. We examined the postrestoration outcome for an ENGO (Nature Conservancy of Canada) project, to assess retroactively how variation in intensity and frequency of sampling would have affected estimates of plant species composition, diversity, and richness over time. The project restored four habitat types (mesic forest, oak woodland, wet meadow, and sand barren) using sculptured seeding of tallgrass prairie and woody species. Species-level plant cover was monitored annually for 10 years in 168 2 × 2-m quadrats. We performed randomization tests to examine estimates of species diversity and richness as a function of the number of quadrats sampled, and assessed the necessity of annual sampling for describing changes in species composition and successional trajectories. The randomization tests revealed that sampling 10-17 quadrats, depending on habitat type, was sufficient to obtain estimates of species diversity that were at least 95% of values obtained from the whole dataset. Species richness as a function of number of quadrats sampled did not plateau, which suggests that rather than increasing the number of sampling quadrats, richness could be estimated more efficiently using nonquadrat based sampling techniques. Nonmetric multidimensional scaling analysis revealed that plant species composition largely stabilized by 3-5 years postrestoration depending on habitat type. By that time, native, seeded species dominated the restoration, and the benefits of annual sampling for tracking changes in species composition diminished.

Interacting ecological filters influence success and functional composition in restored plant communities over time

“…While some studies have found that species composition can stabilize a few years following restoration (Henry et al, 2019; Stuble et al, 2017), our study demonstrates that functional composition can change across microhabitats and over time, at least in our woody‐dominated communities. For example, more stressful microhabitats, such as our south‐facing slopes, may require more management due to lower initial cover (i.e., weeding) early in a restoration project, but planting species with resource conservative traits may lead to increased cover over time.…”

Do or do not. There is no try in restoration ecology

“…Defining restoration outcomes is nontrivial and will continue to be a challenge (Diefenderfer et al ; Svejcar & Kildisheva ; Gellie et al ; Henry et al ). Several novel thinking themes were proposed at the meeting.…”

The importance of sampling intensity when assessing ecosystem restoration: ants as bioindicators in northern Australia

“…Most studies assessing the role of sampling intensity for restoration success target vascular plants (e.g. Viani et al ; Henry et al ); we are unaware of any study that has examined the effect of sampling intensity on assessments of restoration success using insect bioindicators.…”