After the time-intensive process of preparing for the reintroduction and installing it, practitioners often breathe a sigh of relief when the plants or seeds are finally in the ground. However, it is important to realize that the work is not over at this step. Survival and population persistence of the reintroduction depends upon aftercare and no one will be able to learn about the reintroduction unless it is monitored long-term and findings are reported back to the conservation community. The great thing is that aftercare is likely to improve successful establishment and reduce the species’ risk of extinction. Monitoring helps document this success, so it is worth it!
(Vallee et al. 2004)
A well-designed monitoring plan is an essential component of any reintroduction program. To ensure the long-term persistence of a species in the face of environmental change, a long-term monitoring plan is necessary to evaluate how reintroduced populations respond to infrequent events (for example, drought) and to detect changes in the population that mighttake years to express (for example, inbreeding depression in long-lived perennials or replenishing of the soil seed bank). Our goal is not to provide an exhaustive review of how to monitor plant populations, but rather to provide standards for the minimum amount of information needed to evaluate the long-term fate of reintroduced populations. A long-term monitoring strategy will depend upon a number of factors including the trajectory of population growth, the life-history of the focal species, monitoring resources available, and the goals and objectives of the experimental components of the project.
These are the minimum items to consider when establishing a monitoring plan.
|1) Develop clear monitoring objects.||Take into account the life history of the focal species, propagule stage(s) planted, biological and project goals (Pavlik 1996).|
|2) Define sample units.||Use individuals or transplants for demographic monitoring or plot/transect based methods for monitoring demographic structure. All transplants and plots permanently marked and mapped, preferably with GPS.|
|3) Determine appropriate monitoring frequency.||Monitoring period should match key phenological phases (e.g., peak fruiting and flowering) and life-history of the focal species.|
|4) Monitor vital rates.||Follow the fates (survival, growth, fecundity, and recruitment) of transplanted individuals and their progeny or quantitatively track abundance of stage classes (seedling, juvenile, non-reproductive adult, reproductive adult).|
|5) Evaluate fecundity.||Measure seed production by counting the number of fruits per plant and estimate the number of seeds per fruit through sub-sampling. Compare results to reference or natural populations.|
|6) Survey new habitat patches for dispersal and spread.||Search for seedlings at each census both near and far from sample units. Add new recruits to demographic studies, subsample if recruitment densities are large. Conduct searches for the focal species in suitable habitat patches within and beyond the initial planting site. Establish new sample units to monitor the growth and development of new patches/populations.|
|7) Monitor wild reference populations.||Search for seedlings at each census both near and far from sample units. Add new recruits to demographic studies, subsample if recruitment densities are large. Conduct searches for the focal species in suitable habitat patches within and beyond the initial planting site. Establish new sample units to monitor the growth and development of new patches/populations.|
|8) Monitor threats.||Simultaneously monitor reintroduced and natural populations to gain insight into key factors that underlie restoration success. Natural populations should be monitored across several sites and during the same years to capture variation in vital rates for comparison to reintroduced populations.|
|9) Prepare backup plan to relocate lost sample units.||Document all sites and plots with GPS and supplement with precise directions that includes compass directions and measured distance from permanent visible landmarks (Elzinga et al. 1998). Produce GIS layers and maps if possible.|
|10) Archive monitoring data and provide metadata.||Enter, store, and backup all monitoring data in digital files. A minimum of two copies of raw data sheets should be kept on paper file, preferably in separate locations. One copy should be accessible to take into the field during subsequent monitoring events. Metadata should be assembled during the project and continually updated.|
Figure 5.3 — Benchmarks of successful reintroduction. Bars indicate the four benchmarks of a reintroduction: survival, reproduction, recruitment, and dispersal, where dispersal encompasses movement to a new location and establishment. For founders installed as whole plants, the first benchmark is survival, however if founders are seeds, there is an added step. The first benchmark is recruitment, followed by survival, reproductive maturity, next generation recruitment, and dispersal. Species life history and reproductive adult abundance influence duration of time needed to achieve benchmarks. The ability to detect success is constrained by a typical monitoring period of 1-3 years versus the time required to detect recruitment. Turquoise blue arrows denote typical monitoring period, which may be brief and limited by project funding. Grey arrow around circumference of circle indicates lag time to next generation recruitment.
a) For long-lived perennial plants, monitoring plans will need to accommodate changes in population structure over time.
b) For annuals and short-lived species, monitoring plans will need to accommodate temporal and spatial fluctuations in population size (Albrecht and Maschinski 2012; Dalrymple et al. 2012).
c) The method used to monitor seeds will depend upon the sample unit.
d) If demographic monitoring of individuals is not possible, monitor stages or size classes that are most important in maintaining population growth.
e) If demographic monitoring is difficult or impractical, we recommend doing census counts of all or key life-history stages to detect population trends (Menges and Gordon 1996). Examples of species characteristics that may challenge typical monitoring practice include clonal reproduction, seed or plant dormancy or other cryptic life-history stages (for example, tiny seedlings, corms, bulbs).
f) As subsequent generations disperse seed, restricting the census to the original sown plots would fail to capture local dispersal. It will be important to note which microsites are suitable for germination and survival.
(Falk et al. 1996; Vallee et al. 2004; Maschinski, Albrecht et al. 2012)
Documentation is an essential component of reintroduction, and we encourage practitioners to regard their reintroductions not only as activities done for the preservation of species, but as experiments. To this end, we encourage careful documentation so that the reintroduction is justified, that good decisions can be made about preparedness prior to the reintroduction event, that appropriate monitoring can be implemented, and that the data can be analyzed to determine project success. These steps are important to represent accurately the reintroduction from a legal and scientific perspective. (See Dalrymple et al. 2012). (See CPC Best Practice Chapter, “Documentation and Data Sharing”)
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