The fact that several vernal pool restoration and creation attempts in eastern Pennsylvania and New Jersey have been paired with conservation of natural pools in the same area provided a valuable research opportunity to compare amphibian habitat quality between project sites and natural reference pools. To measure desired outcomes, we used successful reproduction and metamorphosis of two vernal pool indicator species, the wood frog and spotted salamander. Although many previous studies indicate that restored and created pools rarely replace function lost in the destruction of natural pools, success of vernal pool indicator species was not necessarily related to pool type in this study. Results indicate a strong correlation between reproductive success for both species and vernal pool size (i.e. mean depth and volume), regardless of pool type. Although overall survival rates of wood frog larvae were significantly higher in natural pools with hydroperiods between 12 and 35 weeks, wood frogs were also successful in one restored and one created vernal pool. Salamander survival rates were highest in two natural and two created pools, which had in common both greater volumes and higher proportions of forest land cover in the surrounding 1,000 m. The documented success of vernal pool indicator species in two well-established created pools demonstrates that pool creation can sometimes restore communities and ecological functions lost, especially when nearby natural pools are degraded or destroyed.
Implications for Practice• Success of amphibian breeding and metamorphosis in vernal pools is not necessarily related to pool type, but quality of mitigation attempts is highly variable. • Well-established created vernal pools with high-quality postbreeding habitat can be beneficial to amphibian populations in the long term. • Practitioners aiming to restore functional habitat for vernal pool species should focus on the relationship between pool volume and hydroperiod, surrounding forest cover, and proximity to natural pools, as these factors appear to be more closely related to amphibian success than others. • Vernal pool restoration and creation projects should be accompanied by extensive monitoring studies that include measures of success beyond amphibian egg mass counts since vernal pools with abundant egg masses do not always have high overall survival rates.
The proposed removal of three run-of-river dams (all ≤5-m height) in eastern Pennsylvania along lower Bushkill Creek, a tributary of the Delaware River, has provided a valuable opportunity for multidisciplinary research involving the collection of more than 5 years of pre-removal monitoring data, analysis of heavy metals in legacy sediment cores, and associated toxicity assays to determine the singular and interactive effects of lead, copper, and cadmium on survival and behavior of a common macroinvertebrate found in Bushkill Creek. Monitoring data were collected from sites approximately 35 m upstream and downstream of dams and reference sites located approximately 5 km upstream of all dams. Results indicate that oxygen levels, macroinvertebrate diversity, and proportion of sensitive taxa were significantly lower upstream and downstream of dams in comparison with upstream reference reaches. The strong correlation between water quality and macroinvertebrates in this system implies that removal of the lower three dams would lead to improvements in water quality, biotic integrity, and resilience in lower Bushkill Creek. Sediment analyses and toxicity assays suggest that dam removal and sediment mobilization may route contaminated sediments downstream at concentrations that may harm more sensitive biota. However, macroinvertebrate mortality and behavior were not significantly different from clean water controls for the large majority of toxicity assays. All together, these results suggest that dams 1-3 are good candidates for successful stream restoration but that the removals would best be planned in a way that mitigates potential impacts of contaminated legacy sediment.
The impact of Hurricane Sandy on the Hudson-Raritan estuary (HRE) provided a valuable case study for exploring interactions between long-term environmental degradation, new climatic disturbance stressors, and human behavioral responses. We extend previous research on the ecological effects of major storms to compare water quality and biological parameters three years before and three years after Hurricane Sandy and consider how ecosystem shifts relate to anglers' perceptions. Results indicate that water clarity and nutrients returned to prestorm conditions in about one year, while shifts in the biological community, including a significant increase in harmful algal species and declines in zooplankton and Atlantic menhaden, persisted for multiple years, and anglers continued to fish amidst ecosystem decline. Biotic recovery time in the HRE was longer than reports for other shallow estuaries frequently disturbed by hurricanes. Ecological and social responses suggest that the post-storm regime shifts and continued fishing pressure could further environmental degradation.
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