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During its life cycle the Calluna vulgaris L. plant passes through four phases related to its age and physiognomy. These are the pioneer, building, mature and degenerate phases. Within each phase, the Calluna plant provides possible habitats for invertebrates within the Calluna-derived litter, on the surface of this litter and in the canopy of the Calluna plant; many invertebrates are also found in the atmosphere above the plant canopy. The invertebrate fauna occurring within the litter includes mites, springtails, false scorpions, harvestmen, spiders, beetles, millipedes, Hemiptera, flies and Hymenoptera. The most numerous and frequently occurring of these are the mites, being almost equally divided into carnivores and those that feed on detritus. The size and diversity of the invertebrate population found within the litter is greatest under pioneer Calluna in heaths that have not been managed by burning, and greatest under degenerate in heaths that have been managed by burning. Otherwise it varies little as the Calluna passes through the different phases. The invertebrate fauna is greatest in numbers and highest in diversity on the surface of the litter. All those found within, the litter also occur in this habitat, often in greater numbers. The numbers and frequency of the beetles and millipedes are greater in this habitat than within the litter, although very few millipedes are found on the litter surface under managed heather. The carnivores and detritus feeders constitute the largest feeding classes. The diversity is greatest under degenerate unmanaged plants and building managed plants. Many more differences in the number of invertebrates are found between phases of managed than unmanaged heather. The invertebrate fauna found within the Calluna canopy includes harvestmen, spiders, springtails, thrips, leafhoppers, spittle bugs, beetles, flies, Hymenoptera and mites. The diversity of their populations in the unmanaged heather is greatest in the canopy of pioneer plants, while in the managed heath it is greatest in the degenerate plants. What few numerical differences are found involve larger numbers in the pioneer than other phases of heather. Many more differences are found between phases of managed than unmanaged heather. The invertebrate fauna found above the Calluna canopy consists mainly of Diptera and Hymenoptera, although spiders, leafhoppers, aphids and beetles are also found. The largest feeding class is the carnivores, animal parasites are found in greater numbers here than elsewhere. The size and diversity of the populations do not differ above different phases of Calluna, both managed and unmanaged, although that above managed heather is lower than that above unmanaged heather. Management by fencing and fertilizing reduces the number of invertebrate families present and has a variable effect on the diversity of the invertebrate populations.

Rapid bioassessment (RBA) methods have largely been used for streams and rivers, with little development of equivalent methods to be used in lakes. This has restricted the assessment of lakes because traditional methods are time- and cost-intensive. Here I show that a newly designed RBA protocol can be used to monitor a wide range of boreal shield lakes effectively. Seventy per cent of lakes with over 25% of their shoreline developed with cottages were assessed as impacted using a multimetric index. This research has built on previous knowledge, placing new emphasis on standardizing sampling efforts by depth, habitat type (cobble sediments) and sample area in lakes. My recommendations provide water resource managers with methods that can be used as a screening tool to monitor a large group of lakes affected by a variety of stressors.

Neuronal regeneration in the mammalian central nervous system (CNS) is severely compromised due to the presence of extrinsic inhibitory signals and a reduced intrinsic regenerative capacity. Understanding the cellular and molecular processes underlying injury and regeneration in the CNS is necessary for the development of effective therapeutic strategies. Lymnaea stagnalis, a freshwater pond snail, has proven to be a powerful model for studying the fundamental mechanisms underlying neurite outgrowth and regeneration. In this study I designed the first custom L. stagnalis microarray gene chip and carried out microarray analysis to profile gene expression changes following CNS injury. From a pool of significantly regulated genes, I provided the first evidence that C/EBP, a transcription factor, plays an integral role in regeneration by maintaining the viability of the distal neurite. We also proposed a novel signaling network and demonstrated that BCL 7 regulates neurite regeneration, an effect that may be mediated through Ca2+-dependent growth cone formation.

Neuronal regeneration in the mammalian central nervous system (CNS) is severely compromised due to the presence of extrinsic inhibitory signals and a reduced intrinsic regenerative capacity. Understanding the cellular and molecular processes underlying injury and regeneration in the CNS is necessary for the development of effective therapeutic strategies. Lymnaea stagnalis, a freshwater pond snail, has proven to be a powerful model for studying the fundamental mechanisms underlying neurite outgrowth and regeneration. In this study I designed the first custom L. stagnalis microarray gene chip and carried out microarray analysis to profile gene expression changes following CNS injury. From a pool of significantly regulated genes, I provided the first evidence that C/EBP, a transcription factor, plays an integral role in regeneration by maintaining the viability of the distal neurite. We also proposed a novel signaling network and demonstrated that BCL 7 regulates neurite regeneration, an effect that may be mediated through Ca2+-dependent growth cone formation.

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