Restoration and Impact Abstracts
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Cumulative Impacts of maritime expansion on endangered seabirds in Algoa Bay, South Africa.
The Southern African Foundation
for the Conservation of Coastal Birds
Algoa Bay is also of considerable economic importance to a highly impoverished region and has been the site of several economic interventions. The expansion of Coega Harbour and the advent of ship-to-ship bunkering nearby were one such interventions. Coega Harbour is located just < 7 kms from St Croix Island and presents an imminent threat to African penguins. The additional vessel traffic to the bay compounds this risk and increases the probability of hazardous events including an oil spill. Not only is there a threat of an oil spill; the increased ship traffic to the bay means elevated noise levels and increased pollution from bilge and ballast water.
Recent research shows a clear link between human-induced activities and the 80% decline in African Penguins on St Croix over a 5-year period. Despite this little is being done to mitigate these impacts and approaches are still very reactionary instead of precautionary. It is essential that economic interventions are balanced against the need for environmental protection. Environmental Impact Assessments need to inform decision-making before economic interventions are implemented and proper contingency and mitigation strategies need to be embedded into legal frameworks to mitigate against harmful events. This research evaluates how one such approach is being implemented in terms of furthering economic development and conserving endangered species.
Long-term impacts of freshwater turtles following the
Kalamazoo River oil Spill
University of Toledo
Sea ducks are the most densely distributed sea bird along the North American coast where they are extremely vulnerable to oil spills, and often a large component of bird injuries. Finding effective restoration actions for sea duck populations is challenging due to their unique life-history strategies and sensitivity to adult annual survival. As long- lived birds with delayed maturity, and generally low reproductive rates, sea ducks are often slow to recover following spills and their populations can be impacted by a single spill for decades or longer. For colonial and cavity-nesting species, nest box programs on breeding grounds are a successful restoration tool, but for other species that breed at extremely low densities across the Arctic and boreal habitats, on-the-ground restoration is limited. Thus, focusing efforts on other areas, at other times of the year may elicit more practical restoration alternatives. In areas where sea ducks congregate or multiple species overlap during the annual cycle, sea duck populations would benefit from direct restoration through habitat creation or prey enhancement, as well as indirect protection of key sites. These protections could occur through spill prevention, safer transport regulation, and emergency preparedness, including staging supply caches and heavy equipment at remote outposts in the high Arctic needed for cleanup in sea ice conditions. For sea duck populations injured by coastal oil spills, increasing the understanding of their varied and unique traits, filling information gaps in baseline vital rates, and identifying important concentration areas and habitat needs would help restoration practitioners implement and prioritize where and when to use restoration actions that have the greatest long-term impact for these unique and difficult to restore taxa.
Post-Release Survival of Rehabilitated Oiled Birds
around the World
International Bird Rescue
In 2010, one of the largest freshwater oil spills and largest dilbit spills in the United States occurred in the Kalamazoo River in Michigan, when over 3.2 million liters of dilbit impacted 56 km of river. In response, cleanup efforts included the capture, rehabilitating, and releasing of more than 2,000 northern map turtles (Graptemys geographica). We documented a nearly 6% direct mortality rate (i.e., individuals captured dead, died in care, or transferred to a permanent rehabilitation center) of sexable northern map turtles. During 2011, 2019, and 2020 we captured turtles within the Kalamazoo River to evaluate changes in the estimated number of individuals in the population, demographics, and size classes nine to ten years later. We found the estimated number of male northern map turtles decreased by ~30% between 2010 and 2011, while females decreased by ~40% between 2011 and 2019. Mean body size of both sexes decreased between 2011 and 2019, due in part to increased recruitment and capture of individuals less than 5 years of age in 2019. Fewer 8–12-year-old females were captured in 2019 and 2020, likely a result of a “lost generation” during the 2010 oil spill. This was evident in that 2% of individuals captured in 2010 were less than 2 years of age, while in subsequent years of survey these age classes made up ~20% of individuals.
In addition, we evaluated the monthly survival probability of turtles 1-14 months post-spill and 8-11 years post-spill based on rehabilitation type; “rehabilitation” (>one night in rehabilitation facility and released in 2010), “overwintered” (overwintered in rehabilitation facility and released in 2011) and “no-rehabilitation” (turtles captured that did not go through any rehabilitation). We found that rehabilitated and overwintered turtles had higher probability of survival 1-14 months post-spill than non-rehabilitated turtles; however, 8-11 years post-spill the differences in survival probability was negligible. To our knowledge, this is the first study of long-term survival impacts of a dilbit oil spill conducted on a vertebrate. Our results show that the 2010 Kalamazoo River oil spill had substantial effects on population size, demographic structure, and sex ratio; however, ten years after the oil spill the population appears to be recovering to pre-oil spill levels, and extensive rehabilitation efforts in the immediate aftermath of the spill likely contributed to this recovery.