| |
Einträge |
Verweise |
|
Autor |
Angermeier, P. L.; Smogor, R. A. |
|
| |
Titel |
Estimating number of species and relative abundances in stream-fish communities: Effects of sampling effort and discontinuous spatial distributions |
Typ |
Zeitschrift, Artikel |
| |
Jahr |
1995 |
Publikation |
Can. J. Fish. Aquat. Sci. J. Can. Sci. Halieut. Aquat |
Kurztitel der Zeitschrift |
|
|
| |
Band |
52 |
Ausgabe |
5 |
Seiten |
936-949 |
|
| |
Schlüsselwörter |
Fisch, Fließgewässer, Habitat, Verbreitung |
|
| |
Zusammenfassung  |
The authors sampled fishes and measured microhabitat in series of contiguous habitat units (riffles, runs, pools) in three Virginia streams. Monte Carlo simulations were used to construct hypothetical series of habitat units, then examined how number of species, similarity in relative abundances, and number of microhabitats accumulated with increasing number of habitat units (i.e., sampling effort). The curves indicated that 90% of the species present were usually found by sampling 5 to 14 habitat units (stream length of 22-67 stream widths). Estimates of species relative abundances required less sampling effort for a given accuracy than estimates of number of species. Rates of species accumulation (with effort) varied among streams and reflected discontinuity in species distributions among habitat units. Most discontinuity seemed to be due to low population density rather than to habitat selectivity. Results from an Illinois stream corroborated our findings from Virginia, and suggested that greater sampling effort is needed to characterize fish community structure in more homogeneous stream reaches. |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
|
Erscheinungsort |
|
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
Natl. Biol. Serv., Virginia Coop. Fish Wildl. Res. Unit, Virginia Polytech. Inst., Blacksburg, VA 24061-0321, USA |
Geprüft |
nein |
|
| |
Rufnummer |
620 |
Signatur |
2414 |
|
| Permalink für diesen Eintrag |
| |
|
| |
|
Autor |
Fore, L. S.; Karr, J. R.; Conquest, L. L. |
|
| |
Titel |
Statistical properties of an index of biological integrity used to evaluate water resources |
Typ |
Zeitschrift, Artikel |
| |
Jahr |
1994 |
Publikation |
Can. J. Fish. Aquat. Sci |
Kurztitel der Zeitschrift |
|
|
| |
Band |
51 |
Ausgabe |
5 |
Seiten |
1077-1087 |
|
| |
Schlüsselwörter |
Umweltverschmutzung, Fisch, Elektrofischerei, Methode, Mathematik, Modell, Statistik, ANOVA |
|
| |
Zusammenfassung |
The authors determined the statistical properties of the index of biotic integrity (IBI) from electrofishing samples collected from Ohio streams. Although IBI is widely used to evaluate the condition of water resources by biologists and resource managers, expanding its role as a regulatory tool depends on statistical validation of its precision and power. We addressed these issues by constructing an additive variance model for IBI and testing the assumptions of that model directly with a bootstrap resampling algorithm and simulations using field data. Statistical properties of IBI supported the use of standard analysis techniques such as ANOVA for hypothesis testing. We determined with power analysis that IBI can distinguish between five and six nonoverlapping categories of biotic integrity based on a model that includes the effects of measurement error, variability of fish assemblages through time, and statistical interaction of location and time. |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
|
Erscheinungsort |
|
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
Inst. Environ. Stud., FM-12, Univ. Washington, Seattle, WA 98195, USA |
Geprüft |
|
|
| |
Rufnummer |
526 |
Signatur |
2325 |
|
| Permalink für diesen Eintrag |
| |
|
| |
|
Autor |
Marquardt, D. W. |
|
| |
Titel |
An algorithm for Least-Squares Estimation of Nonlinear Parameters |
Typ |
Zeitschrift, Artikel |
| |
Jahr |
1963 |
Publikation |
J. Soc. Indust. Appl. Math. |
Kurztitel der Zeitschrift |
|
|
| |
Band |
11 |
Ausgabe |
2 |
Seiten |
431-441 |
|
| |
Schlüsselwörter |
mathematik, marquardt, nichtlinear, methode, algorithmus |
|
| |
Zusammenfassung |
The algorithm discribed shares with the gradient methods their ability to converge from an initial guess which may be outside the region of convergence of other methods. The algorithm shares with the Taylor series method the ability to close in on the converged values rapidly after the vicinity of the converged values has been reached. Thus, the method combines the best feutures of ith predecessors while avoiding their most serious limitations. |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
|
Erscheinungsort |
|
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
|
Geprüft |
nein |
|
| |
Rufnummer |
473 |
Signatur |
2274 |
|
| Permalink für diesen Eintrag |
| |
|
| |
|
Autor |
He, X. |
|
| |
Titel |
Effects of predation on a fish community: A whole lake experiment |
Typ |
Buch |
| |
Jahr |
1990 |
Publikation |
|
Kurztitel der Zeitschrift |
|
|
| |
Band |
|
Ausgabe |
|
Seiten |
|
|
| |
Schlüsselwörter |
predation-; interspecific-relationships; freshwater-fish; population-dynamics; Esox-lucius; Phoninus-eos; Lepomis-; Semotilus-atromaculatus; freshwater-ecology |
|
| |
Zusammenfassung |
Studies of predator-prey interactions have been limited to laboratories or relatively small scale field experiments because of logistic difficulties in large scale field experiments. Much evidence has suggested that predictions based on small scale experiments on predator-prey interactions may not be simply extended to large scales, e.g. whole system. This study was designed to examine predation effects on a prey fish assemblage at the whole lake scale. After a year of premanipulation study, northern pike (Esox lucius) were introduced into a small piscivore-free lake inhabited by 14 species of fishes. In the third and fourth years, the lake was divided by a large mesh fence and northern pike were introduced into one half of the lake. Predation effects on individual prey population were estimated for both direct effects (i.e., consumption of prey species) and indirect effects, including habitat changes associated with predator avoidance behavior, increase of emigration rates and changes of population size structure. The relative importance of direct versus indirect effects was examined using randomized intervention analysis along with a model that quantifies the indirect effects. Decreases of prey fish biomass due to increased emigration was at least as great as that due to the direct effect of consumption when prey biomass was high (>40 kg/ha) but not when prey biomass was low (<30 kg/ha). Significant indirect effects included dramatically decreased abundance of the dominant species (northern redbelly dace, Phoxinus eos), increase of some rare species (sunfish, Lepomis spp. and creek chub, Semotilus atromaculatus), and decreased mean sizes of redbelly dace. Indirect effects occurred rapidly and were most apparent immediately following the introduction of northern pike. Community responses to northern pike predation included changes of species composition, species diversity and community stabilities. The fish communities were significantly different among the pre-pike period, pike period and post-pike period. The greatest variance was related to abundances of redbelly dace and sunfish. However, predation effects on the prey fish community depended on the observational scales used to determine community structure. (DBO) |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
|
Erscheinungsort |
|
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
0 |
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
Zu bestellen |
Geprüft |
|
|
| |
Rufnummer |
|
Signatur |
628 |
|
| Permalink für diesen Eintrag |
| |
|
| |
|
Autor |
Fotland, A.; Mehl, S.; Sunnanaa, K. |
|
| |
Titel |
Methods of index calculation and presentation of fish abundance data using standard computer programs |
Typ |
Buch |
| |
Jahr |
1995 |
Publikation |
|
Kurztitel der Zeitschrift |
|
|
| |
Band |
|
Ausgabe |
|
Seiten |
|
|
| |
Schlüsselwörter |
fishery-management; fishery-statistics; stock-assessment |
|
| |
Zusammenfassung |
Standard 0-group indices and distribution maps are now produced based on hand-drawn maps using AutoCad with some additional procedures. This paper briefly describes the method. The paper further describes ways of importing coastlines and survey data directly into standard computer programs such as AutoCad and SAS. Standard methods are used for gridding data, producing isolines and further calculation of abundance indices and presentation of distributions. Interactive editing of distribution maps are made, which makes corresponding automatic updating of indices possible. |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
|
Erscheinungsort |
|
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
0 |
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
Zu bestellen |
Geprüft |
|
|
| |
Rufnummer |
|
Signatur |
435 |
|
| Permalink für diesen Eintrag |
| |
|
| |
|
Autor |
Kirsten, Oliver |
|
| |
Titel |
Bestandssituation des Dohlenkrebses (Austropotamobius pallipes) im Zartener Becken |
Typ |
Report |
| |
Jahr |
2003 |
Publikation |
|
Kurztitel der Zeitschrift |
|
|
| |
Band |
|
Ausgabe |
|
Seiten |
45 |
|
| |
Schlüsselwörter |
Krebs, Dohlenkrebs, Austropotamobius pallipes, Vorkommen |
|
| |
Zusammenfassung |
Staatsexamensarbeit |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
Albert-Ludwigs-Univeristät |
Erscheinungsort |
Freiburg |
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
|
Geprüft |
nein |
|
| |
Rufnummer |
|
Signatur |
3046 |
|
| Permalink für diesen Eintrag |
| |
|
| |
|
Autor |
Porch, C. E. |
|
| |
Titel |
Trajectory-based approaches to estimating velocity and diffusion from tagging data |
Typ |
Zeitschrift, Artikel |
| |
Jahr |
1995 |
Publikation |
Fish. Bull |
Kurztitel der Zeitschrift |
|
|
| |
Band |
93 |
Ausgabe |
4 |
Seiten |
694-709 |
|
| |
Schlüsselwörter |
dispersion-; migrations-; tagging-; Pisces-; swimming-; models-; dispersal-; migration- |
|
| |
Zusammenfassung |
Several new models are developed to estimate the velocity and diffusion of a population from tagging data. The new estimators apply the inverse principle to the individual trajectories of recovered tags rather than to their local abundance. These models require fewer assumptions and less information than do published abundance-based methods. Techniques are presented for a variety of circumstances, and both discrete and continuous parameterizations of the velocity field are included. The sensitivity of the estimators to violations of the assumptions was examined numerically by using stochastic simulations. The results suggest that the estimators are fairly robust but may fail under certain conditions. Extensions to accommodate these situations are discussed. |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
|
Erscheinungsort |
|
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
Zu bestellen |
Geprüft |
|
|
| |
Rufnummer |
|
Signatur |
1295 |
|
| Permalink für diesen Eintrag |
| |
|
| |
|
Autor |
Speierl, T.; Hoffmann, K. H.; Klupp, R. |
|
| |
Titel |
Fischfauna und Habitatdiversität: die Auswirkungen von Renaturierungsmaßnahmen an Main und Rodach |
Typ |
Zeitschrift, Artikel |
| |
Jahr |
2002 |
Publikation |
Natur und Landschaft |
Kurztitel der Zeitschrift |
|
|
| |
Band |
77 |
Ausgabe |
4 |
Seiten |
161-171 |
|
| |
Schlüsselwörter |
Renaturierung, Gewässersanierung, Habitat, Wasserbau, Fisch, Main |
|
| |
Zusammenfassung |
Seit 1992 wurden im Rahmen des oekologischen Gewaesserbaus an Main und Rodach (Nordbayern) verbaute Flussstrecken renaturiert und eine natuerliche Dynamik wieder zugelassen. Der Vergleich der Fischfauna in zwei repraesentativen Renaturierungsbereichen (Rodachmuendung bei Marktzeuln, Main bei Zapfendorf) mit angrenzenden verbauten Flussabschnitten zeigte den aeusserst positiven Einfluss dieser Massnahmen. In den renaturierten Flussabschnitten wurden in allen Altersklassen (Adulte, Juvenile, Larven) mehr Arten und hoehere Individuenzahlen gefunden als in den verbauten Bereichen. Besonders ausgepraegt war dieser Unterschied bei subadulten Tieren und Fischlarven. Die renaturierten Bereiche fungieren auf Grund ihrer wiedergewonnenen Strukturvielfalt (und damit der Vielfalt an Mesohabitaten) sowohl als Laichplaetze fuer Arten mit unterschiedlichem Anspruch (Kieslaicher Krautlaicher) als auch als Refugium fuer larvale und juvenile Stadien. |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
|
Erscheinungsort |
|
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
|
Geprüft |
|
|
| |
Rufnummer |
|
Signatur |
1596 |
|
| Permalink für diesen Eintrag |
| |
|
| |
|
Autor |
Quartly, G. D. |
|
| |
Titel |
Altimeter repeat-track analysis -- a comparison of various algorithms for producing the mean profile |
Typ |
Zeitschrift, Artikel |
| |
Jahr |
1995 |
Publikation |
J. Atmos. Ocean. Technol |
Kurztitel der Zeitschrift |
|
|
| |
Band |
12 |
Ausgabe |
3 |
Seiten |
674-686 |
|
| |
Schlüsselwörter |
dynamical-oceanography; remote-sensing; satellite-altimetry; sea-level-measurement; geoid-; geostrophic-transport; statistical-analysis; errors- |
|
| |
Zusammenfassung |
Sea surface height may be measured by a satellite-borne altimeter and its along-track slope used to infer geostrophic currents. A major difficulty is that, in general, the local geoid and satellite orbit are not known to the accuracy desired. Thus, comparison is often made between repeat flights of an altimeter along fixed ground tracks in order to infer the changes in the currents. In practice, it is convenient to calculate a mean height profile from many repeat passes and use this as a reference, so that individual altimetric profiles yield variations about this mean. It is thus important to derive a high-quality reliable estimate of the altimetric mean in order to minimize the errors in the inferred flows for the individual repeats. This work examines various methods for deriving the mean profile. |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
|
Erscheinungsort |
|
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
Zu bestellen |
Geprüft |
|
|
| |
Rufnummer |
|
Signatur |
1302 |
|
| Permalink für diesen Eintrag |
| |
|
| |
|
Autor |
Kenchington, E. L.; Full, W. E. |
|
| |
Titel |
Fourier analysis of sea scallop (Placopecten magellanicus) shell in determining population structure |
Typ |
Zeitschrift, Artikel |
| |
Jahr |
1994 |
Publikation |
Can. J. Fish. Aquat. Sci. |
Kurztitel der Zeitschrift |
|
|
| |
Band |
51 |
Ausgabe |
2 |
Seiten |
348-356 |
|
| |
Schlüsselwörter |
population, fourier, statistik, methode, modell, wachstum, muscheln |
|
| |
Zusammenfassung |
Sea scallops (Placopecten magellanicus) were sampled from each of four scallop beds: the northeast peak of Georges Bank, Western Bank, St. Pierre Bank, and the Bay of Fundy near Digby, N.S. The outlines of scallop top shells were captured by video imagery using a semiautomated approach. Fourier shape descriptors were calculated and analyzed. Age and year-class effects were shown to be important factors influencing scallop shell shape. Allometric effects on Fourier harmonics also have a significant influence on shell shape in this species. Comparisons of Fourier harmonics between scallop beds separated by age and sampling year, and corrected for allometry, revealed significant differences in the majority of harmonic numbers. |
|
| |
Adresse |
|
|
| |
Organisation |
|
Abschlussarbeit |
|
|
| |
Herausgeber |
|
Erscheinungsort |
|
Editor |
|
|
| |
Sprache |
|
Sprache der Zusammenfassung |
|
Originaltitel |
|
|
| |
Editor der Reihe |
|
Titel der Reihe |
|
Kurztitel der Reihe |
|
|
| |
Band der Reihe |
|
Ausgabe der Reihe |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Bereich |
|
Expedition |
|
Konferenz |
|
|
| |
Notizen |
|
Geprüft |
nein |
|
| |
Rufnummer |
472 |
Signatur |
2273 |
|
| Permalink für diesen Eintrag |
