- A reintroduction will have a higher chance of successful establishment if it receives water and weeding after installation.
- Keeping land managers apprised of the performance of the rare species and engaging them in active site management is critical for long-term population persistence.
- Developing and implementing a long-term monitoring plan is needed to document the success of the reintroduction.
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!
Conduct Aftercare of the Restored Population
Water plants and seeds until established.
- Account for the amount of effort and time required to transport water for supplemental watering.
- It is possible to set up drip irrigation systems that can be watered from tanks installed on site or transported in pick up trucks.
Periodically weed until plants are well-established.
Ongoing site management is important.
- Collaborators committed to long-term site management should review the status of the site periodically to ascertain whether management is needed. FAQ - Should I manipulate my planting site after the reintroduction?
- Control invasive weeds and competing vegetation.
- Control overabundant herbivores. Cage plants, if necessary.
- Restore historical disturbance regimes such as fire.
- Periodically review the site surveys to detect unforeseen issues (for example, trampling, theft, herbivory, pest insects, vandalism, or maintenance personnel abuse of plants.)
Questions to Ask
Regarding Post Planting
- What aftercare will be needed and how frequently will this require attention?
- What habitat management and threat abatement is needed? How frequently?
- Has a monitoring plan been prepared and reviewed?
- How will success be measured?
- Are sufficient funds available for aftercare?
- Do permits cover aftercare activities?
(Vallee et al. 2004)
Design Appropriate Monitoring Plans
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 might take 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.
Use the reintroduction to learn more about the species.
- Use the reintroduction as an opportunity to learn more about the species, its habitat requirements, and its biotic interactions.
- Incorporate the factors of interest into monitoring plan. Note conditions at the time of installation.
- Document how pollinators and other animals interact with translocated species to improve understanding of the community function in the ecosystem.
Develop a monitoring plan.
- Although all monitoring plans must be tailored to individual projects in order to obtain data relevant to the experimental design and objectives, all reintroduction monitoring plans include basic components needed to provide information relevant to species’ biology and techniques for managing rare plant populations (Table 4.2).
- A well-designed monitoring plan with clear objectives provides information on the species’ biology and techniques for managing rare plant populations. It should be easily understood by your successors, therefore record details as if you are writing for institutional memory.
- If any changes are made to the monitoring plan, then document changes in detail.
Gather demographic data.
- Gather demographic data on the reintroduced population, unless it is not appropriate for the life-history of the target species (Morris and Doak 2002).
- Demographic monitoring of individuals is the method of choice for achieving the central objectives of most rare plant reintroduction projects.
- Specifically, we recommend measuring survival, growth, and reproduction on each plant preferably over multiple generations (Monks et al. 2012).
- For demographic modeling and tracking the success of the reintroduction, determine life history stages (typically seedlings, juveniles, non-reproductive adults and reproductive adults) and note when benchmarks are achieved (See Figure 4.2). FAQ - How will I know if the reintroduction is a success?
- Count the number of seedlings, juveniles, non-reproductive adults, and reproductive adults in your reintroduced population.
- If you plan to develop and compare population dynamic models for the reintroduced population and natural populations, then the frequency of monitoring will need to be at a rate that accurately charts movement of an individual from one life stage to another. FAQ - How often/how long should I monitor my reintroduction?
- Define how large an area you will need to search for recruits.
|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.||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.|
|8) Monitor threats.||Document evidence of changes in: exotic species distribution and abundance, successional patterns, hydrology, disturbance regimes, land management, herbivores, predators, and disease.|
|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.|
Monitor wild reference populations.
- Whenever possible, monitor wild reference populations to compare to the reintroduced population (Bell et al. 2003; Colas et al. 2008; Menges 2008).
- Reference populations will give context for the reintroduced population’s vital rates and aid in identifying the vital rates that are driving population trends (Morris and Doak 2002).
- In augmentations, the fate of augmented individuals and naturally occurring ones should be distinguished in demographic or quantitative censuses when possible to determine whether transplants are performing differently than naturally occurring individuals in the population.
- If available, multiple reference populations should be monitored to capture the full range of variation in vital rates possible across different sites and years.
Adopt an appropriate monitoring strategy.
- Adopt a monitoring strategy that is appropriate for the life history of your target species and the founding propagule used.
a) For long-lived perennial plants, monitoring plans will need to accommodate changes in population structure over time.
- Specifically note when transplants transition into larger size classes and sexually reproduce.
- Tag new seedlings as they recruit into the population.
- Searches beyond the transplant plots or transects will need to be conducted to document dispersal, seedling recruitment and metapopulation dynamics adequately.
- Most monitoring of perennial plants will need to be done at least annually to obtain annualized vital rates. More frequent visits may be necessary to quantify disparate parts of the life cycle such as survival, fecundity, and seed germination.
- For long-lived species (for example, trees), monitoring on an annual basis may not be necessary to detect changes in population trends.
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).
- Track counts of reproductive versus non-reproductive plants that emerge in permanently marked plots or transects across years.
- In annual species, dormancy and germination are often driven by climatic cues that vary from year to year, resulting in wide annual fluctuations in distribution and abundance.
c) The method used to monitor seeds will depend upon the sample unit.
- When sample sizes are small, seeds can be tracked individually. In most cases, however, sow seeds directly into plots so that cohorts can be followed.
d) If demographic monitoring of individuals is not possible, monitor stages or size classes that are most important in maintaining population growth.
- If the importance of the vital rates is known for your taxa, you can concentrate on the most important vital rate and note changes across years to understand population trends.
- If populations begin to decline, then monitoring individuals in all stage classes may be needed to understand mechanisms that are driving the decline and determine what management actions are needed to reverse the decline.
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.
- Regular counts of individuals within grids or belt transects that cover broad areas within the habitat may be needed to fully capture changes in the spatial distribution and abundance over the longer-term and to assess population trends effectively (Young et al. 2008).
Monitor for at least 3 years and if possible for 10 plus years.
- Long-term monitoring provides information necessary to evaluate how reintroduced populations respond to rare events (for example, drought) that were infrequent or nonexistent during the early phase of population establishment. It can reveal genetic issues that might play out only after multiple generations (for example, inbreeding). (Falk et al. 1996; Dalrymple et al. 2012.)
- Ultimately, long-term monitoring is needed to predict the fate of the reintroduced population and determine the mechanisms driving population viability (Albrecht et al. 2011). To develop population viability models and predict population trajectories, a minimum of 3 years of monitoring data are required. To predict long-term trends (10–100 years) and determine whether reintroduced population is potentially self-sustaining under current environmental conditions, extended periods of monitoring are necessary, see Figure 4.2.
- Demographic data will be needed to provide population size estimates for reintroduction plans whose objective is to achieve a specific population size or stage structure.
- 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. (See Elzinga et al. 1998 for more details.)
- Enlist the help of public volunteers to accomplish long-term monitoring (Maschinski, Wright et al. 2012). Whenever possible, include land managers in monitoring to foster a close connection with the reintroduced population.
Use redundancy to mark individuals and plots. Assume that some sample units will be lost over time.
- Although an essential element in all reintroduction plans, long-term monitoring of reintroduced populations can pose formidable challenges. Over time, natural or anthropogenic disturbances can impede access to sites or complicate relocating sample units. For example, plots and transect boundaries or demographic markers can be lost due to fire, flood, downfalls, burial, vandalism, animal impacts, etc.
- Losses can be mitigated with a good insurance plan, which can be used to re-establish or re-locate the boundaries of sample units or tagged individuals when necessary. Whether using plot-based methods or monitoring individuals demographically, there are several ways to ensure the accurate relocation of lost plot markers, transects, and tagged individuals. (See pages 190–191 in Elzinga et al. (1998) for more details.) Submeter GPS points are also helpful.
Determine how success will be measured and have realistic goals.
- Expand definition of success. Identify short-, mid- and long-term success that pertain to the target species and its habitat.
- Remember to think about project success and biological success (Pavlik 1996).
- Comparative mating system studies combined with pollination biology can be carried out over relatively short timeframes (one or two flowering seasons) and can be used to give vital clues to potential recruitment and reproductive success in subsequent generations (Monks et al. 2012).
- Use molecular markers to assess key population processes such as mating system variation and genetic variation in reintroduced populations and, where possible, compare to wild populations to predict reintroduction success (Monks et al. 2012).
Monitoring intensity may change over time.
- As short-term goals are achieved in a reintroduction program, monitoring intensity may change from experimental to observational.
- For example, when reintroducing the perennial forb Helenium viriginicum to sinkhole ponds in the Ozarks, Rimer and McCue (2005) initially set out to determine how planting position and maternal lines affected establishment rates of transplants over a 2-year period. Individuals of the species were grown ex situ, transplanted in a replicated experimental design, and then the fates of transplants were followed demographically. After completing the initial goals of the reintroduction, the populations grew rapidly due to vegetative reproduction and successful seedling recruitment, making it impractical to differentiate transplants and new recruits in subsequent censuses. Because the short-term goals of the experimental design were accomplished, the populations grew rapidly, and the species was capable of completing its life cycle in this location, the monitoring protocol switched to count estimates and surveys for new threats rather than full-scale demographic monitoring of individuals. Likewise, transitioning to observational monitoring may lead to less frequent data collection (for example, annual rather than quarterly) than was needed during the more intense experimental stage.
Analyze data and report results in a timely fashion.
- Report results through publishing or publicizing via social media, newsletters, and websites.
Questions to Ask
Documentation Needed to Justify and Decide Whether to Conduct a Reintroduction
- Survey and status updates are complete. Status includes degree of protection, threats, and management options for the extant populations.
- Specific information on the number of populations has been collated within the last 18 months.
- Counts or estimates of the number of individuals in each population have been done.
- The age structure of the populations is known.
- The relationship of populations in a metapopulation context is compiled.
- Surveys identifying suitable habitat are complete.
- Suitable recipient sites have been assessed and ranked.
- Long-term protection and management plans are documented for suitable recipient sites.
- Sufficient money is secured to conduct the reintroduction.
(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 Part 5 “Documentation and Data Sharing” and North Carolina Reintroduction Documentation Form)
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