Connectivity

(i) Balancing competing interests of resource supply and habitat

Strategic Habitat Conservation Planning

Strategic plans for natural spaces within urban watersheds provide long-term targets and goals for land use planners and policy makers. However, much of this work has targeted where habitat for species may persist on the landscape with little regard for assessing the connectivity of links between habitat patches and identifying where priority mitigation structures may be needed. Here the development of priority corridors for wildlife connectivity will increase the liklihood of biodiversity persistence on the landscape and enhance the potential ecological integrity of a natural heritage system.

Woodland caribou (Rangifer tarandus caribou)

Woodland caribou are a threatened species in Canada that are impacted by the fragmentation and loss of their preferred habitat, mature conifer stands with rich lichen understory. As a result woodland caribou conservation goals come in conflict with the timber industry economic needs (i.e., wood supply). Our main objective is to determine how wood supply should be allocated in order to adhere to industrial economic constraints and woodland caribou environmental requirements. Using four harvesting scenarios (no harvest, no harvest constraints, caribou mosaic (current cut block rotation implemented in Ontario), and a harvest heuristic (based on the amount of wood volume in a stand and the caribou value of a stand)) we find that the harvest heuristic improves and maintains woodland caribou habitat area and connectivity the best, while maintaining current timber harvest levels. Our study highlights that an ecologically-tuned harvesting heuristic may better direct industrial activities to improve woodland caribou habitat while maintaining current wood supply levels.

(ii) Food webs and predator declines

Sharks are subject to harvesting levels that are way beyond sustainable, given that they possess conservative life history traits (e.g. late age of maturation, low fecundity, slow growth rates). This has consequently led to declines throughout the world's oceans and in particular on coral reefs. As top-order predators, sharks can either directly consume or induce costly anti-predator behaviour that can impact top-down structuring of most reef fish communities. In my PhD thesis I took advantage of a unique set of circumstances where reefs off the northwest coast of Australia are either subject to shark removal or not (Scott Reefs and Rowley Shoals, respectively). Using a combination of long-term monitoring data and sharks surveys using Baited Underwater Video Surveys (BRUVS) I was able to compare and isolate top-down and bottom-up effects structuring fish communities. This was achieved at multiple spatial and temporal scales and by using methods such as Structural Equation Models. Alongside this work, I also used data from one of the world's largest reef fish and benthic surveys across the Pacific (Palau to French Polynesia) to determine how these effects (human activity, shark declines and benthic degradation) impact reef food webs across the broad spatial scales.