William W. Taylor

Complexity of Coupled Human and Natural Systems

Integrated studies of coupled human and natural systems reveal new and complex patterns and processes not evident when studied by social or natural scientists separately. Synthesis of six case studies from around the world shows that couplings between human and natural systems vary across space, time, and organizational units. They also exhibit nonlinear dynamics with thresholds, reciprocal feedback loops, time lags, resilience, heterogeneity, and surprises. Furthermore, past couplings have legacy effects on present conditions and future possibilities.

Coupled Human and Natural Systems

Abstract Humans have continuously interacted with natural systems, resulting in the formation and development of coupled human and natural systems (CHANS). Recent studies reveal the complexity of organizational, spatial, and temporal couplings of CHANS. These couplings have evolved from direct to more indirect interactions, from adjacent to more distant linkages, from local to global scales, and from simple to complex patterns and processes. Untangling complexities, such as reciprocal effects and emergent properties, can lead to novel scientific discoveries and is essential to developing effective policies for ecological and socioeconomic sustainability. Opportunities for truly integrating various disciplines are emerging to address fundamental questions about CHANS and meet societys unprecedented challenges.

Compartments revealed in food-web structure

Compartments in food webs are subgroups of taxa in which many strong interactions occur within the subgroups and few weak interactions occur between the subgroups. Theoretically, compartments increase the stability in networks, such as food webs. Compartments have been difficult to detect in empirical food webs because of incompatible approaches or insufficient methodological rigour. Here we show that a method for detecting compartments from the social networking science identified significant compartments in three of five complex, empirical food webs. Detection of compartments was influenced by food web resolution, such as interactions with weights. Because the method identifies compartmental boundaries in which interactions are concentrated, it is compatible with the definition of compartments. The method is rigorous because it maximizes an explicit function, identifies the number of non-overlapping compartments, assigns membership to compartments, and tests the statistical significance of the results. A graphical presentation reveals systemic relationships and taxa-specific positions as structured by compartments. From this graphic, we explore two scenarios of disturbance to develop a hypothesis for testing how compartmentalized interactions increase stability in food webs.

Integrating landscape ecology into natural resource management

List of contributors Foreward Eugene P. Odum Preface Jianguo Liu and William W. Taylor Acknowledgements Part I. Introduction and Concepts: 1. Coupling landscape ecology with natural resource management: paradigm shifts and new approaches Jianguo Liu and William W. Taylor Part II. Landscape Structure and Multi-scale Management: 2. Integrating landscape structure and scale into natural resource management John A. Wiens, Beatrice Van Horne and Barry R. Noon 3. Focal patch landscape studies for wildlife management: optimising sampling effort across scales Julie M. Brennan, Darren J. Bender, Thomas A. Contreras and Lenore Fahrig 4. Managing for small patch in human-dominated landscapes: cultural factors and corn belt agriculture Robert C. Corry and Joan Iverson Nassauer 5. A landscape approach to managing the biota of streams Charles F. Rabeni and Scott P. Sowa 6. Linking ecological and social scales for natural resource management Kristiina A. Vogt, Morgan Grove, Heidi Asbjornsen, Keely B. Maxwell, Daniel J. Vogt, Ragnhildur Sigurdardottir, Bruce C. Larson, Leo Schibli and Michael Dove Part III. Landscape Function and Cross-boundary Management: 7. Assessing the ecological consequences of forest policies in a multi-ownership province in Oregon Thomas A. Spies, Gordon Reeves, Kelly Burnett, William McComb, K. Norman Johnson, Gordon Grant, Janet Ohman, Steve Garman and Pete Bettinger 8. Incorporating the effects of habitat edges into landscape models: effective area models for cross-boundary management Thomas D. Sisk and Nick M. Haddad 9. Aquatic-terrestrial linkages and implications for landscape management Rebecca L. Schneider, Edward L. Mills and Daniel C. Josephson Part IV. Landscape Change and Adaptive Management: 10. A landscape transition matrix approach for landscape management Virginia H. Dale, Desmond T. Fortes and Tom L. Ashwood 11. Tactical monitoring of landscapes Dean L. Urban 12. Landscape change: patterns, effects and implications for adaptive management of wildlife resources Daniel T. Rutledge, Christopher A. Lepczyk and Jianguo Liu 13. Landscape ecology in highly managed regions: the benefits of collaboration between management and researchers John B. Dunning Jr. Part V. Landscape Integrity and Integrated Management: 14. Putting multiple use and sustained yield into a landscape context Thomas R. Crow 15. Integrating landscape ecology into fisheries management: a rationale and practical considerations W. W. Taylor, D. B. Hayes, C. P. Ferreri, K. D. Lynch, K. R. Newman and E. F. Roseman 16. Applications of advanced technologies in studying and managing grassland landscape integrity Greg A. Hoch, Brent L. Brock and John M. Briggs 17. An integrated approach to landscape science and management Richard J. Hobbs and Robert Lambeck Part VI. Syntheses and Perspectives: 18. Bridging the gap between landscape ecology and natural resource management Monica G. Turner, Thomas R. Crow, Jianguo Liu, Dale Rabe, Charles F. Rabeni, Patricia A. Soranno, William W. Taylor, Kristiina A. Vogt and John A. Wiens 19. Landscape ecology of the future: a regional interface of ecology and socioeconomics Eugene P. Odum 20. Epilogue Richard T. T. Forman Index.

Effect of egg and larval survival on year-class strength of lake whitefish in grand traverse bay, lake michigan

Abstract A study was conducted in Grand Traverse Bay, Lake Michigan, during 1983 and 1984 to identify factors that are important in determining year-class strength of lake whitefish Coregonus clupeaformis. The major determinants of year-class success were overwintering egg survival and the amount of food available to larval lake whitefish during the first 7 weeks of life, Egg mortality was related to the timing of ice cover, with an early cold winter producing the highest survival. Larval survival was affected by the abundance of available prey, i.e., copepod zooplankton between the sizes of 0.7 and 1A mm in total length. In 1983, when zooplankton of this size were abundant relative to larval fish density, high rates of growth and survival of lake whitefish ensued. In 1984, the prey-per-fish ratio declined greatly, and poor growth and low survival were observed. The dynamics of these early life stages appear to significantly influence both lake whitefish year-class strength and eventual recruitment in Gra...

The Effect of Illegal Harvest on Recreational Fisheries

Abstract The degree of compliance with a fishing regulation can have a significant impact on the regulations effectiveness. In this paper, we use a yield-per-recruit simulation model to evaluate the effect of poaching on legal harvest in sport fisheries. Two types of illegal harvest were considered: harvest of fish below the legal size limit and harvest of fish from catch-and-release fisheries. The results depict the degree of reduction in legal harvest in minimum-size fisheries with 0-100% (in 10% increments) illegal harvest. For brook trout Salvelinus fontinalis, the reduction in legal harvest ranged from 11% at 10% illegal harvest to 72% at 100% illegal harvest; these reductions ranged from 10 to 66% for northern pike Esox lucius, 8 to 57% for brown trout Salmo trutta, and 2 to 22% for largemouth bass Micropterus salmoides. In catch-and-release fisheries, illegal harvest reduces the number offish caught and released. Most ofthe benefits ofcatch-and-release regulations, in terms of increased numbers an...

Lake Trout Mortality and Abundance in Southern Lake Huron

Abstract Populations of lake trout Salvelinus namaycush in the main basin of Lake Huron collapsed in the 1940s because of predation by sea lampreys Petromyzon marinus and commercial fishing. Efforts to rehabilitate lake trout have emphasized reduction of mortality and the stocking of hatchery-reared lake trout to reestablish populations. We fit a statistical catch-at-age model for lake trout in the southern main basin of Lake Huron using a maximum likelihood approach to estimate mortality rates and abundance during 1984–1993. This represents the first such analysis for lake trout in the Great Lakes, and a flexible application of the approach proved useful for integrating diverse information and assessing population and mortality trends. Sea lamprey-induced mortality and recruitment of lake trout to age 1 were calculated external to model fitting. Recruitment was based on numbers of lake trout stocked because natural recruitment is negligible. Sea lamprey-induced mortality rates were based on observed woun...

An Index of Cumulative Disturbance to River Fish Habitats of the Conterminous United States from Landscape Anthropogenic Activities

Reversal of widespread fish habitat degradation in the conterminous United States will require effective spatial planning, which begins with spatial assessment of current habitat conditions. We present an assessment of cumulative anthropogenic disturbance to fish habitats in approximately 2.23 million U.S. river reaches under the assumption that downstream local habitat conditions will reflect conditions in the catchment upstream. We used geographic information systems data to attribute 15 disturbance variables to the catchments of mapped river reaches to calibrate an index of cumulative disturbance that considered effects originating from both local and upstream catchments. The influence of each variable was adjusted in the index based on the results of multiple linear regression analyses of all variables against percent intolerant fishes at a site—a commonly used biological indicator of habitat condition. Urban landscape indicators were weighted most heavily, followed by point-source pollution, pasture lands, and dam densities. Local factors were found to be less influential on fishes than those originating from the upstream river network. Skewed cumulative disturbance scores indicated that disturbance levels of some reaches far exceeded the national median. Future assessments should include stratification of analyses within regions, expanded use of response metrics and datasets, and alternative analytical approaches to help tease apart the influences of interacting landscape disturbance types. We demonstrate how our results can be visualized and used to make regional comparisons among large-scale planning units and also show how reach-level information about upstream versus local disturbance levels can be used to identify potential habitat management strategies that are suitable to different landscape contexts.

Absorption of whistler mode waves in the ionosphere of Venus

It is shown that whistler mode waves from the ionosheath of Venus are absorbed by Landau damping at the dayside ionosphere boundary. This process heats the ionospheric electrons and it may provide an important energy input into the dayside ionosphere. Cyclotron damping of the waves does not occur in the same region. However, Landau damping of ionosheath waves is apparently not an important energy source in the nightside ionosphere. Impulsive events in the nightside ionosphere seem to fall into two classes: (i) lightning signals (near periapsis) and (ii) noise, which may be caused by gradient or current instabilities.

Factors Affecting the Recruitment of Lake Whitefish in Two Areas of Northern Lake Michigan

Stock-recruitment and integrated recruitment models incorporating biotic and abiotic factors were developed for lake whitefish populations in northern Green Bay and the North Shore areas of Lake Michigan. Abundance and recruitment indices were calculated for the 1961-1985 year classes based on lake whitefish catch and effort data from the commercial fishery in each area. Previous research indicates that spawning stock abundance, winter ice cover, and spring temperatures are important in determining the egg and larval abundance and survival of lake whitefish. Therefore, spawning stock abundance, ice cover, winter wind velocity, and spring water and air temperature variables were used as model inputs in regression modeling. The biotic/abiotic recruitment model for northern Green Bay hindcasted lake whitefish recruitment as a function of spawning stock abundance and the number of days that ice cover exceeded 40% during egg incubation. This regression model (R2 = 0.62) demonstrated improved hindcasting ability of historic recruitment when compared to the Beverton-Holt (R2 = 0.37) or the Ricker (R2 = 0.33) stock-recruitment models for the 1961-1985 cohorts. The biotic/abiotic recruitment model for the North Shore hindcasted lake whitefish recruitment as a function of average air temperature in May after larval emergence, the number of days that ice concentration exceeded 70% during egg incubation, and spawning stock abundance. The regression model (R2 = 0.57) also demonstrated improved hindcasting ability of historical recruitment when compared with Beverton-Holt (R2 = 0.09) or the Ricker (R2 = 0.13) stock-recruitment models. Results of this study indicate that biotic/abiotic recruitment models were more successful in hindcasting recruitment than solely biologically based stock-recruitment relationships. Consideration of significant abiotic variables will be useful in the management of lake whitefish stocks in the Great Lakes by improving forecasts of recruitment.