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Einschätzung der fischökologischen Bedeutung urbaner Kleingewässer am Beispiel der Stadt Bremen - The ecological significance of small urban waters for fish biodiversity shown using the example of the city of Bremen
Abstract and Figures
Zusammenfassung: Die Bedeutung urbaner Kleingewässer als Lebensraum für Fische ist bisher kaum untersucht. Im inneren Stadtgebiet von Bremen wurden in zwei Befischungsserien (Herbst 2012, Frühjahr 2013) 17 städtisch geprägte Kleingewässer befischt. Nachgewiesen wurden 16 Arten mit insgesamt 3.071 Individuen (im Mittel Herbst/Frühjahr 0,35 Fische/m 2). Dominierend waren indifferente (Habitat) oder phyto-lithophile bzw. phytophile (Reproduktion) Arten. Die häufigste Art war das Rotauge Rutilus rutilus (51,4 %), gefolgt von Zwergstichling Pungitius pungitius (12,5 %) und Gründling Gobio gobio (11,4 %, jeweils bezogen auf den Gesamtfang). Die Art mit der weitesten Verbreitung (an 11 von 16 Probestellen) war der Hecht Esox lucius. Mit dem Steinbeißer Cobitis taenia wurde eine Art des Anhangs II FFH-Richtlinie nach-gewiesen. Auch wenn Herbst-und Frühjahrsbefischung insgesamt ähnliche Ergebnisse zeigten, waren die räumlichen und zeitlichen Verbreitungsmuster sehr heterogen. Im Vergleich mit den naturschutzfachlich und fischkundlich bedeutsamen Gewässersystemen in den NATURA 2000-Gebieten im Bremer Grünlandgürtel war die Fischfauna nur unwesentlich artenärmer. Defizite waren bei bestimmten auentypischen Arten festzu-stellen. Insgesamt zeigte das Gewässersystem ein hohes fischökologisches Potenzial, welches bei zukünftigen Maßnahmen zur innerstädtischen Grünflächenentwicklung ("green spaces" und "blue spaces") in Zusammenarbeit zwischen Naturschutz, Wasserwirtschaft und Stadtentwicklung gezielt gefördert werden sollte.
Summary: The importance of small urban water bodies as a habitat for fish has hardly been investigated to date. In the inner city of Bremen, 17 small urban waters were fished in two fishing series (autumn 2012, spring 2013). 16 species with a total of 3,071 individuals (average 0.35 ind./m 2) were found. The dominant species were indifferent (habitat) or phyto-lithophilic or phytophilic (reproduction) species. The most common species was the roach Rutilus rutilus (51.4%), followed by the dwarf stickleback Pungitius pungitius (12.5%) and the gudgeon Gobio gobio (11.4%, based on total catch). The species with the widest distribution (11 out of 16 samples) was the pike Esox lucius. A species listed in Annex II of the Habitats Directive has been identified with the spined loach Cobitis taenia. Although autumn and spring fishing showed similar results, the spatial and temporal distribution patterns were very heterogeneous. In comparison with the nearby ditch-wetland areas in the NATURA 2000-sites, which are important for nature conservation and fish species conservation, the fish fauna was only marginally species-poorer. Deficits were observed in certain typical floodplain species. Overall, the water system showed a high fish ecological potential, which should be specifically promoted in future measures for inner city green space development ("blue spaces") in cooperation between nature conservation, water management and urban development.
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Diese schlichte Frage ist gar nicht so einfach zu beantworten. Die spontane, und im Grundsatz auch nicht verkehrte Antwort für die Binnengewässer lautet zwei: den Dreistachligen Stichling Gasterosteus aculeatus und den Zwergstichling Pungitius pungitius, der oft auch als Neunstachliger Stichling bezeichnet wird. In Nord- und Ostsee kommt dann noch als dritte Art der Seestichling Spinachia spinachia, jedoch als rein marine Art, hinzu. Die Unterscheidung der beiden im Süßwasser vorkommenden Arten ist sehr einfach. Schaut man jedoch einmal in die Literatur, kommt Verwirrung auf.
Neben Fragen zur zur aktuell etwas verwirrenden Taxonomie und Systematik enthält der Beitrag detaillierte Informationen über die Verbreitung der verschiedenen Formen des Dreistachligen Stichlings in Nordwestdeutschland.
Background Previous studies revealed a relationship between residential green space availability and health, especially mental health. Studies on blue space are scarcer and results less conclusive.
Aims To investigate the hypotheses that green and blue space availability are negatively associated with anxiety and mood disorders, and positively associated with self-reported mental and general health.
Method Health data were derived from a nationally representative survey (NEMESIS-2, n =6621), using a diagnostic interview to assess disorders. Green and blue space availability were expressed as percentages of the area within 1 km from one’s home.
Results The hypotheses were confirmed, except for green space and mood disorders. Associations were generally stronger for blue space than for green space, with ORs up to 0.74 for a 10%-point increase.
Conclusions Despite the different survey design and health measures, the results largely replicate those of previous studies on green space. Blue space availability deserves more systematic attention.
Declaration of interest None.
Copyright and usage © The Royal College of Psychiatrists 2016. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.
The world's population is concentrated in urban areas. This change in demography has brought landscape transformations that have a number of documented effects on stream ecosystems. The most consistent and pervasive effect is an increase in impervious surface cover within urban catchments, which alters the hydrology and geomorphology of streams. This results in predictable changes in stream habitat. In addition to imperviousness, runoff from urbanized surfaces as well as municipal and industrial discharges result in increased loading of nutrients, metals, pesticides, and other contaminants to streams. These changes result in consistent declines in the richness of algal, invertebrate, and fish communities in urban streams. Although understudied in urban streams, ecosystem processes are also affected by urbanization. Urban streams represent opportunities for ecologists interested in studying disturbance and contributing to more effective landscape management.
Summary
The near shore fish fauna of the highly structurally modified and polluted river Weser in the municipal area of Bremen was examined at eleven sampling sites (nine of them in the tidal Lower Weser) during the period from 2008 to 2012 by using electrofishing and beach seine. A total of 1,279 individuals from 23 species were recorded. The dominant species were roach Rutilus rutilus, ide Leuciscus idus, perch Perca fluviatilis, flounder Platichthys flesus, common goby Pomatoschistus microps, dace Leuciscus leuciscus and bleak Alburnus alburnus. Worthy of remark were the records of stone loaches Barbatula barbatula in a renatured area of the lower Middle Weser and common bullheads Cottus gobio in the tidal Lower Weser, both as first records for the Weser in Bremen. Also notable were sporadic catches of juvenile barbels Barbus barbus. Especially for small benthic fish species the results suggest that there is potential for habitat improvement in the developed, tidal Lower Weser as well as in the canalized lower Middle Weser. Furthermore a first record of the invasive round goby Neogobius melanostomus was documented which is increasing in range. From the occurrence of the species Neogobius melanostomus significant changes in the near-shore fish species communities can be expected.
Zusammenfassung
Die ufernahe Fischfauna der strukturell stark veränderten und belasteten Weser im Stadtgebiet von Bremen wurde an elf Probestellen (davon neun in der Unterweser) im Zeitraum von 2008 bis 2012 mittels Elektrofischerei und Uferzugnetzen untersucht. Insgesamt wurden 1.279 Individuen aus 23 Arten nachgewiesen. Die dominierenden Arten waren Rotauge Rutilus rutilus, Aland Leuciscus idus, Flussbarsch Perca fluviatilis, Flunder Platichthys flesus, Strandgrundel Pomatoschistus microps, Hasel Leuciscus leuciscus und Ukelei Alburnus alburnus. Fischfaunistisch bemerkenswert waren Nachweise von Bachschmerlen Barbatula barbatula im renaturierten Bereich der unteren Mittelweser und von Groppen Cottus gobio in der Unterweser, beide als Erstnachweise für die Weser in Bremen. Ebenfalls bemerkenswert waren vereinzelte Fänge von juvenilen Barben Barbus barbus. Die Ergebnisse legen nahe, dass sowohl in der ausgebauten, tidebeeinflussten Unterweser als auch in der kanalisierten unteren Mittelweser Potentiale zur Lebensraumverbesserung vor allem für benthische Kleinfischarten bestehen. Ebenfalls als Erstnachweis wurde die invasive Schwarzmundgrundel Neogobius melanostomus dokumentiert, die im Gebiet offensichtlich in Ausbreitung befindlich ist und von der erhebliche Veränderungen in den ufernahen Fischartengemeinschaften zu erwarten sind.
Regarding the restoration of potamal river courses the lateral connectivity among lotic streams (main stream, side branches, floodways) and lentic water bodies (backwaters, oxbows, ponds) within the floodplains should receive an increased attention. The fish ecological importance of water bodies within floodplains includes three considerable aspects:
1. Enduring connection of back-waters (especially as spawning, nursing and overwintering habitats of eurytopic and rheophlic fishes of type-B).
2. Temporarily connectivity of water bodies, that are hydrological isolated to a great extent, as prerequisite for the equilibrium of processes concerning recolonization and extinction in the sense of the insular zoogeography theory.
3. The existence of water bodies with abiotic conditions, which are hostile to most of the potamal fishes, as niches for pronounced habitat specialists. The weatherfish Misgurnus fossilis and the crucian carp Carassius carassius are examples for fishes that are
adapted to water bodies of an advanced
successional status. In contrast, the spined
loach Cobitis taenia and the bitterling
Rhodeus amarus represent potamal fishes that inhabit water bodies of a former
successional status. The low pressure of
predation, which is typical for these water
bodies, is discussed to be of considerable
importance to the occurrence of the bit
terling. At east, the blue bream Abramis
ballerus represents potamal fishes that inhabit permanently connected back-waters and large, periodically connected oxbows. The principles of floodplain ecosystem restoration could be derived from the biology of the cited potamal fishes. Therefore, the co-occurrence of back-waters that are permanently connected with the main stream and water bodies only temporarily connected during flood events is of special importance for the fish community of floodplains. These apparently inconsistent requirements to lateral connectivity as well as the existence of water bodies in a different successional status are only guaranteed by the "chaos" of natural flood dynamics.
Background:
A growing number of quantitative studies have investigated the potential benefits of outdoor blue spaces (lakes, rivers, sea, etc) and human health, but there is not yet a systematic review synthesizing this evidence.
Objectives:
To systematically review the current quantitative evidence on human health and well-being benefits of outdoor blue spaces.
Methods:
Following PRISMA guidelines for reporting systematic reviews and meta-analysis, observational and experimental quantitative studies focusing on both residential and non-residential outdoor blue space exposure were searched using specific keywords.
Results:
In total 35 studies were included in the current systematic review, most of them being classified as of "good quality" (N=22). The balance of evidence suggested a positive association between greater exposure to outdoor blue spaces and both benefits to mental health and well-being (N=12 studies) and levels of physical activity (N=13 studies). The evidence of an association between outdoor blue space exposure and general health (N=6 studies), obesity (N=8 studies) and cardiovascular (N=4 studies) and related outcomes was less consistent.
Conclusions:
Although encouraging, there remains relatively few studies and a large degree of heterogeneity in terms of study design, exposure metrics and outcome measures, making synthesis difficult. Further research is needed using longitudinal research and natural experiments, preferably across a broader range of countries, to better understand the causal associations between blue spaces, health and wellbeing.
The present knowledge about the fish population of the river Weser is reviewed with special emphasis on the lower section (Unterweser). Thirty-four species of fish were recorded in the Unterweser during our faunal survey between 1981-1984. At least four species that were common in former times are known to have become extinct within this century. Another six species are threatened or in danger of extinction. The history of the river fishery on the Unterweser is described. Trends of stock development of economically valuable species within the last hundred years were obtained by evaluation of catch statistics. Biological interactions among fish and their prey were elucidated by food investigations. Invading crustaceans were found to be most important in supporting the fish population. Fish in the upper- and middle parts of the Weser are heavily affected by severe salt pollution: fish density and diversity have been reduced considerably within the last two decades and the remaining individuals are unhealthy to a larger degree. Concentrations of heavy metal and chlorinated carbohydrate pollutants in bream and white bream are given.
