Appendices 7-24 (PDF, 3.4MB)
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APPENDIX 7.0 – Connectivity Introduction Connectivity is the ecological term that describes connections among habitats, species, communities, and ecological processes, enabling the flow of energy, nutrients, water, natural disturbances, and organisms and their genes at many spatial and temporal scales (Noss and Harris,1989; Noss,1991). Connectivity corridors support biodiversity by: maintaining opportunities for genetic exchange between populations (Merriam,1991): allowing for gradual shifts in the distribution of species and ecosystems in the event of catastrophic events; and enhancing the management of rare habitats for red and blue-listed species, other regionally significant species, and rare ecosystems that are under-represented in protected areas. There is significant evidence that connectivity corridors aid the continuity and stability of populations (including plants, small and large mammals, birds and other organisms). The loss of connectivity, often referred to as fragmentation, is considered by some to be the greatest threat to natural biodiversity (Harris,1984; Wilcox and Murphy,1985; Wilcove et al., 1986; Noss,1991). Fragmentation of habitat results in reduced habitat quality leading to isolated populations, reduced resilience and extirpations (Spies et al.,1994). Although there are challenges to carrying out studies of connectivity at a landscape level, the benefits of landscape corridors such as riparian areas are well documented. It is also possible that connectivity corridors may play a role in a changing climate by allowing plants and animals to make landscape-scale movements along the changing climate gradient to avoid adverse environments (Hobbs and Hopkins,1991). Connectivity is recognized as an appropriate indicator to measure how effectively a particular land use regime contributes to the maintenance of biodiversity and opportunities for the movement of species and genetic material over time and across landscapes. Connectivity can be achieved through a combination of land-use designations, including the designation of Protected Areas, special management areas, and the establishment of conservation-oriented management objectives in the appropriate land units. Understanding connectivity requires viewing ecological systems over larger areas and longer time frames than most people are accustomed to - tens of thousands of square kilometres and many decades or even centuries. Over such scales, species’ distribution and abundance are not static but fluctuate with changing climatic and ecological conditions. Local populations may become temporarily extirpated but may be recolonized if connectivity among populations exists. In addition to maintaining long-term movement potential, connectivity permits gene flow that ensures genetic variability is maintained. Genetic variability, although probably not as important as maintaining meta-population dynamics, may be important with respect to reducing the negative effects of inbreeding and maintaining the ability of species to evolve and adapt to local conditions (B. McLellan, 2002 pers. comm.). Benefits of Connectivity Connectivity or habitat linkages serve to: • mitigate the negative impact of ecosystem and species fragmentation by providing contiguous movement and dispersal corridors between suitable habitats • facilitate migration between seasonal habitats through provision of certain requirements such as security cover • maintain genetic diversity within a population by facilitating movement and genetic exchange between populations • allow organisms to establish in new areas or previously occupied areas • aid the continuity and stability of populations of plants, small and large mammals, birds and other organisms • facilitate the flow of energy, nutrients, water, natural disturbances, and organisms and their genes at many spatial and temporal scales • mitigate adverse impacts to natural biodiversity • reduce the threat of decreased habitat effectiveness which can precipitate isolation of populations, lower reproduction potential, negatively affect poor recruitment to unoccupied habitats, and reduce resilience potentially resulting in extirpations Risks to Connectivity The risk to successful fulfilment of connectivity is high if: • representation is not achieved by Biogeoclimatic Ecosystem Classification (BEC) • habitats are not maintained in a proper functioning condition • access planning does not recognize the sensitivity of wildlife to the effects of cumulative industrial and recreational access activities • compliance and enforcement is low • barriers which adversely affect gene flow are not addressed An example of risk within the SRMMP relates to the Highway 3 corridor, comprised of the highway, railway, towns and associated developments, that collectively create a fracture or physical barrier precipitating movement limitations which could subsequently reduce genetic variability among grizzly bear populations located North and South of the highway (M. Proctor 2002). Although many species, such as deer and elk, can live for months in the Highway 3 corridor and successfully move across this area, grizzly bears are less likely to do so. Although they are found in the corridor, they are more likely to become attracted to garbage, fruit trees, composts, or pet foods, and, because bears are potentially hazardous to people, they are frequently removed. DNA from most grizzly bears collected north of the Highway 3 corridor can be clearly differentiated from DNA collected from bears on the south side, suggesting that the Highway corridor has begun to fracture the population (B. McLellan, 2002 pers. comm.). To ensure the viability of populations of bears and other species on either side of the Highway 3 corridor, maintaining connectivity is clearly a principle wildlife conservation goal. If connectivity is not maintained, the risk to individual species like grizzly bear, which have a low tolerance to human activity or are less mobile with respect to their ability to disperse, locate and utilize suitable habitats, can be high. Connectivity in a Forest Matrix Context As opposed to applying a conventional linear or corridor approach to connectivity, the forest matrix concept involves the integration of access planning with mature and old representation, specific habitat identification and zoning and the development of related habitat conservation regimes across the landscape. This concept was applied to the landscapes within the Southern Rocky Mountain Management Plan (SRMMP). Essentially, the forest matrix concept involves the spatial identification of: • core grizzly bear security zones, • old growth management zones and mature forest zones (where specified by the Higher Level Plan), • high to moderate ranked avalanche tracks, • riparian zones, • ungulate winter range, and • inoperable forested and non-forested components of the forest harvesting land base. Appropriate conservation and access management objectives are then specified to ensure proper functioning condition and optimum habitat effectiveness. From a strategic wildlife conservation perspective, connectivity is obviously important. The challenge confronting land use planners using the forest matrix approach is to determine: • an ecologically effective means of achieving proper functioning condition and habitat effectiveness through the maintenance of connectivity, • a realistic and practical operational method of implementing and achieving connectivity objectives at a landscape level, and • an effective and balanced industrial, public and commercial recreation access plan that sustains functional connectivity. Connectivity in the SRMMP Area Within the SRMMP area, a decision was made to digress from the KBLUP-IS linear connectivity concept and address the development and implementation of connectivity in a forest matrix context. The logic for achieving the goals of connectivity and habitat effectiveness through this approach was based on the opinion that this concept would: • be more ecologically appropriate • be based on complementary science and local knowledge • address the entire landscape as opposed to a singular corridor Anecdotal and scientifically-based information, required to develop and support this concept, was acquired through separate public and research connectivity workshops which, respectively generated pertinent input from commercial guides, recreationalists, hunters, local experts, scientists, foresters and biologists Information was gathered related to: • the identification (through anecdotal and standardized inventories) of ungulate and wide ranging carnivore locations and distribution by season • the identification of key daily and seasonal movement routes • determining what constitutes connectivity • determining how connectivity can be quantified • the identification of discrete habitats and core security areas that are required to support connectivity • determining how the identified habitats could be managed over time • determining, from an ecosystem based perspective, that the connectivity line work and concept is appropriate and scientifically defensible • determining that the support inventory is comprehensive • developing management direction which would ensure that functional connectivity would be sustained and would realistically contribute to wildlife conservation management • the operational practicality of achieving connectivity through the forest matrix concept • identification of connectivity gaps • the development of best management objectives and stewardship practices