Monitoring Biological Responses to restoration: temporal and spatial shifts in the community structure of amphibians and reptiles in restored and retired cranberry bogs.
completion of Critical Data Gaps
Future directions
We underscore the importance of continuous monitoring for amphibians and reptiles in these restored cranberry bogs as a metric to evaluate the success of restoration, particularly with a long-term focus. We underscore that amphibian and reptile communities also reflect the hydrological, vegetation, and soil properties, therefore monitoring these communities can shed valuable insights on restoration effectiveness.
Monitoring herpetofauna as a metric of restoration success
Herpetofauna are pivotal indicators of wetland ecosystem health due to their heightened sensitivity to environmental changes, such as contamination by agro-chemicals or nutrients. Furthermore, herpetofaunal diversity metrics align with the diversity of other native wetland wildlife, highlighting their role as biodiversity surrogates. As both predators and prey, the presence of herpetofauna can influence food webs within restored wetlands, emphasizing their importance in ecosystem dynamics. Our propose that monitoring strategy encompass various aspects of herpetofaunal community diversity, such as species richness, species-specific and cumulative abundance, and species composition. These well-established metrics can characterize healthy, self-sustaining wetland ecosystems. Thus, by monitoring herpetofaunal community structure, we can effectively evaluate (1) the success of restoration efforts, (2) the efficacy of intervention actions and restoration designs, and (3) the temporal changes in restored wetlands over time.
The monitoring approach we propose also incorporates species composition analyses, employing a species-turnover-based approach to compare community-wide species shifts across a chronosequence of wetland restoration. This comparison enables us to quantify the success of wetland restoration efforts over time, comparing wetlands of different restoration ages. We propose to compare all metrics across the wetland chronosequence to quantify the success of wetland restoration. The relative magnitude of each metric will indicate the effectiveness of restoration efforts and how the restoration outcomes manifest over time. Additionally, both species richness and relative abundance of environmentally sensitive, habitat specialist, or conservation-dependent herpetofaunal species can further indicate restoration success.
Contributions of herpetofauna monitoring to improv in restoration practice
The herpetofaunal monitoring plan we proposed is designed for replication across different sites and timeframes, including locations where various restoration techniques have been applied. For instance, monitoring amphibian larval community composition (species identity and larvae abundance) and amphibian reproductive efforts (measured through species-specific egg-mass abundance) can investigate how amphibian larval community composition varies in response to pit-and-mound topography, woody debris cover, surface-water cover, and vegetation cover. The engineering of surface microtopography during restoration introduces habitat heterogeneity, with woody debris providing overwintering habitats for freshwater turtles and snakes. This heterogeneity influences habitat structure and resource distribution, impacting faunal diversity, such as amphibian reproduction and recruitment. We can implement variable designs of microtopographic complexity and experiment which specific design is most suitable for recruiting regional, native assemblages of amphibians into restored sites. Our herpetofaunal survey methods can be stratified at different wetland/aquatic habitats, including ponds of varied sizes, streams restored with variable sinuosity, and wetlands/streams with varied ground-water connectivity. Thus, our monitoring protocol can be retrofitted to conduct experiments on various forms of surface microtopography and restoration designs. Thereby, our findings can inform restoration design principles to improve standard practices.
The wetland ecohydrology and spatial complexity of restored ecohydrology significantly impact wetland herpetofaunal communities. Increased groundwater discharge, for example, can create thermally stable, optimal wetland environments for amphibian and reptile growth and reproductive success. However, optimizing these practices for wildlife and biodiversity conservation in restored wetlands remains unexplored. Moreover, retired cranberry bogs can provide habitats for conservation-dependent herpetofauna, potentially serving as founder populations once bog restoration is complete. Therefore, our surveys yield valuable information on pre-restoration community structure, informing restoration designs and practices to mitigate on-site disturbances.
The herpetofaunal monitoring protocol we propose not only offers valuable insights into current restoration efforts but also serves as a blueprint for future restoration projects. By replicating our studies across diverse restoration sites and implementing our survey methods in various wetland and aquatic habitats, we can refine restoration interventions and enhance habitat quality for herpetofauna and other wildlife.
Frequency of herpetofauna monitoring
To ensure comprehensive evaluation and understanding of wetland restoration outcomes, frequent and extended monitoring of herpetofauna is essential. Our research has demonstrated rapid responses within 1-2 years post-restoration, as well as medium to long-term responses observable exceeding 5 years after restoration. Pre-restoration monitoring is crucial to capture the existing herpetofaunal community, including conservation-dependent species, which can influence subsequent long-term changes. Therefore, we propose annual surveys at specific sites for at least two years pre-restoration to establish the baseline data. Continued monitoring in the early phases post-restoration (2-3 years) is vital for detecting invasive species and assessing founder populations. Medium-term monitoring at 5 and 7 years post-restoration provides insights into the wetland's progress towards restoration goals and identifies any need for additional interventions, including headstarting, population augmentations, or breeding site/nest protection. Long-term monitoring at 10, 15, and 20 years post-restoration evaluates slower responses, such as colonization by rare and conservation-dependent species, and assesses if desired restoration goals have been achieved. The proposed monitoring sequence not only generates robust evaluation metrics but also informs improvements to restoration practices, particularly regarding the timing and nature of intervention strategies. By tracking the variance in post-restoration developmental trajectories across different site types and restoration methodologies, we can identify factors that facilitate or inhibit favorable outcomes.
Designing monitoring plans to Inform future restoration actions
To inform future restoration actions and design a monitoring plan to document pre-restoration diversity, comprehensive baseline surveys of amphibian and reptile communities must be conducted before any restoration activities begin. This includes species identification, abundance estimation, and habitat usage. Standardized survey methods such as visual encounter surveys, pitfall traps, and coverboards should be utilized to ensure consistent data collection. Recording environmental parameters, including water quality, vegetation cover, and temperature, will help correlate species presence and abundance with habitat conditions.
Implementing an adaptive restoration approach is essential to minimize disturbance. Restoration actions should be executed in sequential phases, starting with smaller areas and gradually expanding as founder populations establish in newly restored habitats. Monitoring the immediate impact of restoration on herpetofauna will allow for adjustments to practices, ensuring minimal disruption to existing communities. Restoration efforts should be designed to create diverse microhabitats that support different life stages and species of herpetofauna. This includes features like pit-and-mound topography, woody debris, and varied vegetation cover. Maintaining or enhancing existing features that provide critical habitats for conservation-dependent species is also crucial.
A long-term monitoring plan should be established, including short-term (2-3 years), medium-term (5-7 years), and long-term (10-20 years) intervals post-restoration. Key indicators such as species richness, abundance, reproductive success (e.g., egg-mass counts), and habitat quality should be monitored. Using both fixed and random sampling sites will capture spatial and temporal variations in herpetofaunal communities. Statistical analyses should be employed to compare pre- and post-restoration data, identifying significant changes in herpetofaunal diversity and abundance. Species distribution models can predict potential shifts in community composition due to restoration activities.
Finally, continuously evaluating monitoring results is vital for adaptive management. Any negative impacts on herpetofauna must be addressed promptly. Incorporating lessons learned from previous projects will optimize restoration designs and interventions for future initiatives. By following these recommendations, future restoration actions can effectively document pre-restoration diversity, protect existing herpetofaunal communities, and enhance habitat quality to support long-term conservation goals.
June 26, 2024