LTREB: Long-term Dynamics of Moose Populations, Community Structure, and Ecosystem Properties on Isle Royale

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The objective of this project is to determine the long-term dynamics of how moose affect plant species distribution, ecosystems, and landscapes at several different spatial and temporal scales. This will allow integration individual behavior with population and ecosystem ecology. The previous work has demonstrated that selective browsing by moose on hardwoods increases dominance of spruce, which in turn depresses soil nitrogen availability because of poor litter quality. It has also been found that these effects are distributed non-randomly across the landscape, and derive from the effects of browsing on plant competition, seed rain and seed bank dynamics. Through an explicitly spatial simulation model of a foraging moose it has been shown that: 1) browsing by individual moose imposes structure on initially random landscapes; 2) that structure as well as the energetic status of the moose depends greatly on the foraging strategy used (e.g. Markovian foraging vs. foraging according to the marginal value theorem): and 3) the foraging strategy affects the energetic status of the moose. Three years of study have suggested that episodic, cyclic, and transitional processes determine the sequence of how ecosystems change in response to browsing and how foraging decisions are subsequently altered. These processes occur at very different time scales along a continuum from short-term to long-term. Such processes, ranging from short to long-term, include revisitation of browsed plants by moose, cyclic patterns of seed rain depending on mast years, recruitment and mortality of plants determining the sequence of invasion of browsed patches by unbrowsed plants, and changes in soil N availability resulting from manuring and changes in litterfall. The sequences of short-term events partially determine long-term trajectories. Conversely, long-term trends may be in opposite directions from that of some local short-term events. It is crucial that short-term results be placed in the context of long-term trends. %%% Research of this nature is fundamental to the better understanding of complex ecological systems. Such knowledge, as it is gained, is almost immediately applicable to the management of living resources; more for sustainable hunting, timber resources, and water quality as well.