Janice L. Pappas

Fish Utilization of Great Lakes Coastal Wetlands

Correspondence analysis was used to partition fish species associated with the open water of each of the five Great Lakes and nine coastal wetlands for which data were available. Included in the analysis were 113 species in 25 families. Three species complexes were suggested: a Great Lakes taxocene (31 species); a transitional community which utilized open water, nearshore, and wetlands (35 species); and a wetlands taxocene, comprised of 47 species found to be closely associated with coastal wetlands. The wetland species split into two main groups: permanent residents (e.g., brown bullhead Ictalurus nebulosus, mudminnow Umbra lima, longnose gar Lepisosteus osseus) and migratory species. Migratory species included three subgroups: (1) those that spawned in the wetlands and then left (e.g., northern pike Esox lucius, common carp Cyprinus carpio, white sucker Catostomus commersoni, walleye Stizostedion vitreum), (2) those that used the wetlands as a nursery area (e.g., northern pike, gizzard shad Dorosoma cepedianum, spottail shiner Notropis hudsonius), and (3) those that migrated into the wetland from other wetlands or a Great Lake for shelter, spawning sites, or food; as part of the sustaining process of dispersal of young; or as part of wandering behavior (e.g., burbot Lota lota, rainbow smelt Osmerus mordax, rainbow trout Oncorhynchus mykiss). It was found that most remaining coastal wetlands are degraded or altered to some degree, and are dominated by a characteristic silt- and turbidity-tolerant fish fauna (e.g., common carp, gizzard shad, goldfish Carassius auratus, and brown bullhead). Nevertheless, even degraded wetlands still functioned as important fish habitat by exporting large quantities offish, first to avian, piscine, and mammalian food chains through predation, and second to the Great Lakes as young-of-the-year sport and forage fish. The research implies that a wetland must maintain a connection with a Great Lake to promote and enhance efficient fish utilization of the high productivity of marshes; that additional resilience is provided to species which spawn in wetlands since they can produce two cohorts (one in wetlands and one in the Great Lakes), and that fluctuating water levels are important in sustaining habitat diversity and productivity.

QUANTITATIVE METHOD FOR DETERMINING A REPRESENTATIVE ALGAL SAMPLE COUNT1

A method for determining a representative count of a sample dependent on number of species is presented for application to various algal communities. Constant species curves are calculated as efficiency = (number of individuals–number of species)/number of individuals and diagrammed on a plot of efficiency versus number of individuals counted. Efficiency is defined as the probability that a new species encountered is minimal. That is, as the ratio of number of species to number of individuals approaches 1, more individuals will need to be counted in order to achieve a representative count. Data and calculations of efficiency from two algal communities are presented for illustration.

Legendre shape descriptors and shape group determination of specimens in the Cymbella cistula species complex

Abstract Ten Legendre shape descriptors were calculated for 66 specimens in the Cymbella cistula species complex from the Great Lakes. One-hundred x,y co-ordinates were used to calculate the width function W(x) = ∑n=oN bn Pn (x) to obtain the Legendre coefficients(bn) as shape descriptors. Principal components analysis (PCA) was performed on Legendre shape descriptors for the whole valve outline, to determine a shape gradient. A second PCA was performed on Legendre shape descriptors for the dorsal side of the valve outline. From this, nine shape groups were determined. From multiple discriminant analysis (DA), all but the third and eighth shape groups had near-perfect specimen assignment. Misassigned specimens from these shape groups were assigned instead to adjacent groups in PCA shape space. Overall, a curved trajectory in PCA shape space may reflect the degree of valve shape complexity. That is, there is a progression in PCA shape space from dorsally semicircular and somewhat arcuate to crescentic with a ventrally gibbous midvalve region. The distinct shape groups found indicated that several species may be present in the C. cistula complex.

QUANTITATIVE ANALYSIS OF SHAPE VARIATION IN TYPE AND MODERN POPULATIONS OF MERIDION (BACILLARIOPHYCEAE)

Subtle differences in valve morphology can indicate sexually isolated populations in diatoms (Bacillariophyceae). Shape descriptors, like Legendre coefficients, have been used to quantify differences in valve outline so that morphologically distinct groups can be recognized. Legendre coefficients were used as shape descriptors to quantify differences in valve outline among five populations in the genus Meridion Ag. Two novel populations of Meridion from North America, a North American population of M. constrictum Ralfs, type material for M. circulare (Greve.) Ag., and type material of M. constrictum were included in this analysis. Results of a principle components analysis and discriminate analyses on the shape descriptors of all five populations support the hypotheses that the two novel North American populations are undescribed taxa within Meridion and that the North American M. constrictum can be considered Meridion constrictum sensu stricto. A new taxon, Meridion hohii Rhode, is described. There appears to be greater diversity within the genus Meridion than is currently recognized.

Calculating shape descriptors from Fourier analysis: shape analysis of Asterionella (Heterokontophyta, Bacillariophyceae)

Abstract In our study, shape descriptors were calculated for specimens from the diatom genus Asterionella, using the method of arc lengths and tangent angles in Fourier analysis. Asterionella species are character-poor, populations being distinguished mostly by subtle shape differences. Fourier analysis has been used in the past as an aid in taxonomy for many organisms. Fourier coefficients are least-squares estimators of best-fit planar closed curves that provide a quantitative measure of shape and can be useful shape descriptors in character-poor organisms. We determined the relation between number of x,y coordinates and the number of Fourier coefficients used in shape analysis for Asterionella. In a worked example, using a single extracted specimen outline, the method of calculating Fourier coefficients is demonstrated; coefficients were calculated for 100, 140, and 200 coordinates, in order to determine how many coordinates are necessary for effective shape analysis. Then, for each in a size range of Asterionella specimens, Fourier coefficients were calculated, using the same number of coordinates for each. Reconstructed outlines were compared graphically with the original. Statistical measures of average difference, variance, standard deviation, and coefficient of variation were calculated between xs, ys and Euclidean distance for the original and reconstructed outlines. From this, using 100 x,y coordinates, the number of Fourier coefficients necessary to give the best-fit outline over a size range from 30 to 95 μm is 22. Although we used Asterionella as an example, the method may be applied to any diatom valve outline.

Effects of Inorganic Nitrogen Enrichment on Lake Huron Phytoplankton: An Experimental Study

Abstract Effects of inorganic nitrogen (NO 3 ) enrichment on phytoplankton were studied using a factorial design experiment. Using species assemblages from Lake Huron waters, the effects of NO 3 and total phosphorus (TSP) additions on species abundance and composition were monitored. The species-nutrient relationship was determined by canonical correspondence analysis (CCA). In addition, divisional differences were related to nutrient additions using correspondence analysis (CA). These techniques were instrumental in developing species relationships to NO 3 and TSP gradients and, by partialling out the effect of TSP to determine the primary species- NO 3 relationship. Nitrate-phosphorus (N:P) effects were also analyzed at the species and divisional levels. Gross changes in biomass, as represented by chlorophyll a concentrations, were not evident from NO 3 enrichment. However, species composition did change, particularly for a few species. Most evident were increases in relative abundance of Cyclotella comensis. Cyclotella stelligera, Fragilaria capucina, F. pinnata , and flagellates showed similar increased proportional abundance. Flagellates responded positively to both NO 3 additions and N:P interactions. Overall, there were not great changes at the level of major algal divisions. All major groups maintained their abundances relative to one another throughout the experimental period. The results from this study showed that increased NO 3 levels in the Great Lakes would affect species composition.

Phytoplankton assemblages, environmental influences and trophic status using canonical correspondence analysis, fuzzy relations, and linguistic translation

Abstract In a global assessment, canonical correspondence analysis (CCA) and partial CCA were used to ordinate Lake Huron phytoplankton abundances from June and August 1991 and environmental variables. June taxa were associated with NO3 and chloride, while August taxa were associated with SiO2 and temperature, and to some degree, with TSP and NH3. Dominant taxa were Asterionella formosa, Fragilaria capucina, Fragilaria crotonensis, Tabellaria fenestrata, and Urosolenia eriensis in June, and Achnanthidium minutissimum, Cyclotella #6, Cyclotella comensis, Cyclotella michiganiana, and Cyclotella pseudostelligera in August reflecting seasonal change. From local analysis using results from CCA and partial CCA in fuzzy relational analysis, A. minutissimum and C. comensis were influential in June, while F. crotonensis was influential in August. From linguistic translation and trophic status assignment, F. capucina and T. fenestrata indicated eutrophy, A. formosa indicated mesotrophy, C. pseudostelligera indicated mesotrophy–eutrophy, F. crotonensis and U. eriensis indicated oligotrophy–eutrophy, Cyclotella #6 indicated oligotrophy–mesotrophy, and C. michiganiana indicated oligotrophy. A linguistic solution with respect to trophic status is useful for policy makers and others interested in understanding water quality and ways to develop decisions about remediation.

Biological taxonomic problem solving using fuzzy decision-making analytical tools

Biological taxonomy is at the heart of species identifications. Such identifications are instrumental in biodiversity studies, ecological assessment, and phylogenetic analysis, among other studies. Fuzzy measures and classification integration was used to analyze shape groups of the diatom Asterionella using fuzzy Fourier shape coefficients and fuzzy morphometric measures. Based on this analysis, six shape groups were determined with specimen membership assignments at or exceeding the crossover point (0.5). Fuzzy average overlap values were approximately at or just over the crossover point, indicating similarity in developmental stages. In further analysis, spatial and temporal data from specimen samples were used in conjunction with fuzzy membership assignment values. Spatial and temporal variables were ranked and fuzzified based on the mode. The modes were then weighted by degree of importance as determined by an expert in diatom research. The weighted fuzzy modes for each specimen in each shape group were aggregated as a weighted sum. The normalized relative cardinality for each specimen defined the degree of suitability that a specimen belonged to a shape group, and the expert evaluated the result. While morphological data specifies inheritance (shape) and development (morphometry), spatial and temporal data were proxies for reproductive isolation. These biological principles constrained and defined the direction of analysis and defined each shape group as a species to the degree specified by each specimen. This fuzzy decision-making process provided a simple way to aggregate scant available data and a linguistic solution in a taxonomic study understandable to a biologist.

A Generalized Approach to the Modeling and Analysis of 3D Surface Morphology in Organisms

The surface geometry of an organism represents the boundary of its three-dimensional (3D) form and can be used as a proxy for the phenotype. A mathematical approach is presented that describes surface morphology using parametric 3D equations with variables expressed as x, y, z in terms of parameters u, v. Partial differentiation of variables with respect to parameters yields elements of the Jacobian representing tangent lines and planes of every point on the surface. Jacobian elements provide a compact size-free summary of the entire surface, and can be used as variables in principal components analysis to produce a morphospace. Mollusk and echinoid models are generated to demonstrate that whole organisms can be represented in a common morphospace, regardless of differences in size, geometry, and taxonomic affinity. Models can be used to simulate theoretical forms, novel morphologies, and patterns of phenotypic variation, and can also be empirically-based by designing them with reference to actual forms using reverse engineering principles. Although this study uses the Jacobian to summarize models, they can also be analyzed with 3D methods such as eigensurface, spherical harmonics, wavelet analysis, and geometric morphometrics. This general approach should prove useful for exploring broad questions regarding morphological evolution and variation.

Multivariate measure of niche overlap using canonical correspondence analysis

Abstract:A measure of multidimensional niche overlap based on species scores from canonical correspondence analysis is presented. This measure, N, is the amount of overlap using species scores as approximate weighted averages with respect to multidimensional niche breadth for the community given by N = 0 - [(ui - uj)’ V-1 (ui - uj) g |V|]. Multidimensional niche overlap was calculated for a representative periphytic community from northern Lake Huron. Classification of species interaction or species similarities was accomplished using cluster analysis of the multidimensional niche overlap values. Two major groups of taxa showing similarities were evident based on niche influence. This influence produced a gradation of species found in clean waters to those found in varying degrees of pollution.