Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. 
The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. 
The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. 
The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

http://snobear.colorado.edu/Markw//WatershedBio/10/Week15/Carpenter.pdf

Cascading Trophic Interactions and Lake Productivity

Most empirical and theoretical studies of resource use and population dynamics treat conspecific individuals as ecologically equivalent. This simplification is only justified if interindividual niche variation is rare, weak, or has a trivial effect on ecological processes. This article reviews the incidence, degree, causes, and implications of individual-level niche variation to challenge these simplifications. Evidence for individual specialization is available for 93 species dis- tributed across a broad range of taxonomic groups. Although few studies have quantified the degree to which individuals are specialized relative to their population, between-individual variation can some- times comprise the majority of the population's niche width. The degree of individual specialization varies widely among species and among populations, reflecting a diverse array of physiological, be- havioral, and ecological mechanisms that can generate intrapopu- lation variation. Finally, individual specialization has potentially im- portant ecological, evolutionary, and conservation implications. Theory suggests that niche variation facilitates frequency-dependent interactions that can profoundly affect the population's stability, the amount of intraspecific competition, fitness-function shapes, and the population's capacity to diversify and speciate rapidly. Our collection of case studies suggests that individual specialization is a widespread but underappreciated phenomenon that poses many important but unanswered questions.

/pdf/the-ecology-of-individuals-incidence-and-implications-of-1qvkodaqfy.pdf

The Ecology of Individuals: Incidence and Implications of Individual Specialization

Fish assemblage structure, and factors and mechanisms appearing important in the ecological maintence of these structures, were examined for 18 small lakes in northern Wisconsin during summer and winter. The study was focused around the following questions. Are there discrete, repeatable groups of fish assemblages? If so, are they temporally stable? What are the relations between fish assemblage structure and habitat complexity, physical disturbance, biotic interactions and the insular nature of small lakes? A comparative approach was used to generate hypotheses and propose explanations concerning the roles of these factors in structuring the assemblages. Multivariate classification, ordination, and discriminant analyses helped discern two assemblage types: Umbra—cyprinid and centrarchid—Esox. Each had a distinctive species composition and seasonal change in composition. Environmental characteristic of the lakes occupied by each assemblage type also differed consistently. The type of assemblage present in a lake appeared related to oxygen concentrations in winter, interacting with the availability of refuges from either a severe physical environment (low oxygen during winter) or from large pisvivores. Centrarchid—Esox assemblages occurred in lakes with high winter oxygen levels, and also in lakes with low oxygen if a stream or connecting lake could provide a refuge from these conditions in winter. When no refuge was present, low winter oxygen lakes lacked piscivorous fishes, but contained Umbra—cyprinid assemblages. The relationships between species richness in summer and environmental factors were generally similar for the two assemblage types, but the relative importance of individual factors differed. In winter, richness relationships in centrarchid—Esox assemblages for most environmental factors were reversed from those of summer. No significant seasonal change occurred in the Umbra—cyprinid assemblages. Habitat complexity factors, particulary vegetation diversity, were significantly related to summer species richness in both assemblage types. Lake area was also related to summer richness for both types, but the slope of the species—area regression was much steeper for Umbra—cypinid assemblages than for those in centrarchid—Esox lakes. Species richness relationships with winter oxygen concentration were negative in both seasons in Umbra—cyprinid lakes, but the relationship was positive for centrarchid—Esox assemblages in winter. A measure of lake connectedness was related to summer richness in centrarchid—Esox lakes. These patterns suggest that centrarchid—Esox assemblages are in ecological equilibrium but that a disturbance—induced disequilibrium occurs in Umbra—cyprinid assemblages.

https://era.library.ualberta.ca/items/882030ec-c143-4156-9b2d-8fcf76ffef0c/view/f3383288-4e44-445c-937f-4bdc9ab9935f/Ecology_63_1982_1149.pdf

Patterns in the Species Composition and Richness of Fish Assemblages in Northern Wisconsin Lakes

We compared characteristics of fish assemblages from Finland and northern Wisconsin on several scales to investigate community-level similarity in environmentally similar but faunistically different small lakes. Although Finland has only half as many fishes in its regional species pool, local species richness did not differ between the two regions. Variability in species composition among assemblages was lower in Finland, suggesting that a large proportion of the fauna could maintain populations across a broad range of environmental conditions, whereas the Wisconsin fauna was composed of more specialized species. Three types of fish assemblages were identified in Wisconsin based on species' presence or absence, whereas on the same scale, Finnish assemblages presented a hierarchical continuum based on species addition. These and other patterns suggest that habitat specialization and the exclusion of small prey species from lakes with piscivores contribute to the occurrence of presence-absence assemblage ty...

/pdf/intercontinental-comparison-of-small-lake-fish-assemblages-19coqz9xvi.pdf

Intercontinental comparison of small-lake fish assemblages: the balance between local and regional processes

Many autecological effects of temperature on fish are known, and fishery biologists have begun to incorporate this knowledge into population-level relations that can be used to assess possible effects of climatic warming on fishes and their habitats. However, the problem of extrapolating these or other relations to multispecies assemblages is not straightforward, given the complexity of community-level phenomena. I present a conceptual framework that views fish assemblages as products of a series of filters, operating at different spatial and temporal scales, through which an assemblage's component species must pass. This framework can facilitate an understanding of the processes that organize fish assemblages and suggest ways in which the complex problem can be divided into manageable pieces. I apply this framework in an examination of small-lake fish assemblages in three regions on two continents. The procedure reveals local and regional relations of richness and composition and highlights the ...

/pdf/climate-change-and-fish-communities-a-conceptual-framework-1u4hed0n91.pdf

Climate Change and Fish Communities: A Conceptual Framework

– We examined whether solvent-based lipid extractions, commonly used for stable isotope analysis (SIA) of biota, alters δ15N or δ13C values of fish muscle tissue or whole juvenile fish. Lipid extraction from muscle tissue led to only small (<1‰) isotope shifts in δ13C and δ15N values. By contrast, ecologically significant shifts (+3.4‰ for δ13C and +2.8‰ for δ15N) were observed for whole juvenile fish. Sample variance was not affected by lipid extraction. For tissue-specific SIA, two sample aliquots may be required: a lipid-extracted aliquot for stable carbon isotope analysis when differing lipid content among tissues is a concern, and a nonextracted aliquot for δ15N determination. Whole organism SIA is not recommended because of the mix of tissues having different turnover times; for very small fish, we recommend that fish be eviscerated, decapitated, and skinned to minimise differences with samples of muscle tissue.

Resumen

1. Cada vez con mayor frecuencia, los ecologos de peces utilizan analisis de isotopos estables. Por ello, se hace cada vez mas importante comprender las fuentes de variacion, - debido a diferencias inherentes entre muestreos biologicos o como resultado de tecnicas de procesamiento de muestreo - tanto como identificar estrategias para tratar tales fuentes. Examinamos si la extraccion de lipidos basada en disolventes, comunmente utilizada en analisis de isotopos de carbono estable, altera negativamente los valores de δ15N y δ13C de tejido muscular de tres peces de tamano pequeno y de peces juveniles completos.



2. La extraccion de lipidos de musculo de pez llevo a pequenos cambios isotopicos de + +0.4 a +1.0‰ y de +0.3 a +0.5‰ para δ13C y δ15N, respectivamente. Por el contrario, la extraccion de lipidos de peces juveniles completos vario marcadamente en +3.4‰ para δ13C y +2.8‰ para δ15N - ambos cambios ecologicamente importantes. La varianza de los valores de muestreos de δ13C y de δ15N tanto para tejido muscular como para los peces completos no difirieron entre los muestreos de lipidos extraidos y muestreos sin tratamiento.



3. Nuestros resultados recomiendan el analisis de isotopos estables de tejidos especificos. Cuando ello no es posible o deseable, dos alicuotas de muestreo pueden ser requeridas: una alicuota de lipidos extraidos para el analisis de isotopos de carbono estable cuando la varianza de δ13C, debida a diferencias en el contenido de lipidos de diferentes tejidos, y una alicuota de no-extraccion para determinaciones de δ15N.



4. Dada la mezcla de tejidos, el analisis de isotopos de un organismo completo no es recomendable – en el caso de peces muy pequenos, recomendamos que los peces sean eviscerados, decapitados, y despellejados para minimizar las diferencias de muestreos de tejido muscular.

Effects of lipid extraction on stable carbon and nitrogen isotope analyses of fish tissues: potential consequences for food web studies

The probability of catching a fish in a gill net may be separated into two components: (1) the probability of the fish encountering the net and (2) the probability of the fish being caught and retained in the net We consider the probability of encounter to be directly proportional to the distance travelled by the fish during the sampling period This distance will increase with fish size if different-sized fish swim for the same amount of time because swimming speed increases with fish size Routine swimming speed measured in the laboratory for three size-classes of bloater (Coregonus hoyi) increased with length to the 08 power Corrections for encounter probability were incorporated in gill net selectivity calculations for samples of cisco (Coregonus artedii), a species closely related to bloater These corrections can significantly increase the proportional estimates of smaller relative to larger animals in the estimated population structure The approach should also be applicable to other passive fis

William M. Tonn

Papers

Patterns in the Species Composition and Richness of Fish Assemblages in Northern Wisconsin Lakes

Intercontinental comparison of small-lake fish assemblages: the balance between local and regional processes

Climate Change and Fish Communities: A Conceptual Framework

Effects of lipid extraction on stable carbon and nitrogen isotope analyses of fish tissues: potential consequences for food web studies

Size Selectivity of Passive Fishing Gear: A Correction for Encounter Probability Applied to Gill Nets