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Recovery Strategy for the Eastern Prickly Pear Cactus (Opuntia humifusa) in Canada

Appendix 1: Effects on the Environment and Other Species

The ecosystem type within which Eastern Prickly Pear Cactus occurs, the Lake Erie Sand Spit Savannas, is among the rarest and most imperiled terrestrial ecosystems in North America. This ecosystem supports a large number of species, including 40 other species at risk at the provincial or national scale.

Broad approaches and strategies aimed at the recovery of the Eastern Prickly Pear Cactus are expected to either have no significant adverse impacts or to positively affect other species in the Lake Erie Sand Spit Savannas. Negative environmental effects arising from this strategy will likely be confined to the use of vegetation management techniques. Habitat modifications to enhance suitability for Eastern Prickly Pear Cactus may have adverse effects on other species but by applying appropriate mitigation measures these are not expected to be significant. Potential adverse effects associated with fire management techniques are not expected to be significant. Effects could include potential loss of individuals, including Eastern Prickly Pear Cactus and other species at risk, potential damage to archaeological resources, potential loss of mature forest habitat cover and thicket and woodland habitats, loss of downed woody debris that provides important microhabitat for many Lake Erie Sand Spit Savanna species, potential displacement of existing vegetation if Eastern Prickly Pear Cactus is repatriated to historic locations, the potential disturbance of soil contaminants and potential impacts to visitor experience due to the control of off-trail activities. The potential loss of individuals from trampling and disturbance due to monitoring activities could also occur.

The approaches currently outlined are mainly oriented towards research, monitoring, and protection. Threat assessments undertaken for Eastern Prickly Pear Cactus may benefit other species by clarifying threats that have impacts beyond just that species. Monitoring work may include assessments of cactus habitat, thereby increasing knowledge relating to both the ecosystem and closely associated species.

Similarly, education and communication activities relating to the Eastern Prickly Pear Cactus generally include information relating to both the ecosystem and other component species, thereby conferring benefits to these other species. Activities aimed at preventing the collection of Eastern Prickly Pear Cactus may help other species, like the Five-lined Skink (Plestiodon fasciatus), as well as some turtles and snakes, which are valued by collectors.

The implementation of any vegetation management program should involve follow-up to determine the success of the techniques implemented, in addition to the impacts on other species, ecosystem processes and the environment. This will allow for adaptive management at these sites, the mitigation of any environmental effects and continual adjustment and improvement of recovery efforts.

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