Handwerksreform 2004 – Rückwirkungen auf das Ausbildungsverhalten Lüneburger Handwerksbetriebe?

Die Befragung Lüneburger Handwerksbetriebe, die im Rahmen eines Projektes zur Regulierung auf dem deutschen Handwerksmarkt in Zusammenarbeit mit der Kreishandwerkerschaft Lüneburg durchgeführt wurde, soll Auswirkungen der Anfang 2004 erfolgten Handwerksreform erfassen. Dabei liegt der Schwerpunkt dieses Artikels auf der Ausbildungsleistung des Handwerks. Die theoretischen Ansätze zur Erklärung betrieblicher Lehrstellenangebote sollen mit den Ergebnissen der ersten Befragungsrunde über die Determinanten der Ausbildungsentscheidung im Lüneburger Handwerk konfrontiert werden.

Mehr Wettbewerb im Handwerk durch die Handwerksreform?

Die Anfang 2004 durchgeführten Reformen auf dem Handwerksmarkt hatten vor allem eine Erleichterung des Marktzutritts und damit mehr Wettbewerb zum Ziel. Die erwartete Zunahme der Anbieter, durch die es zu sinkenden Preisen und einer steigenden Nachfrage kommen soll, konnte zumindest auf Teilmärkten beobachtet werden. Der Artikel soll anhand von Beispielen des sehr heterogenen Handwerksmarkts aufzeigen, wie sich der Wettbewerb unter der Annahme unterschiedlicher mikroökonomischer Modellkonstellationen (vollständige Konkurrenz, Monopol, monopolistische Konkurrenz und Qualitätswettbewerb) entwickelt. Auf Grundlage einer Ende 2004 in Zusammenarbeit mit der Kreishandwerkerschaft Lüneburg durchgeführten Befragung Lüneburger Handwerksbetriebe sollen dazu erste ökonometrische Auswertungen vorgestellt werden, die sich mit den Auswirkungen der Reform auf die wirtschaftliche Lage der Betriebe befassen.

Sind ausbildende Handwerksbetriebe erfolgreicher?

Für die Neufassung der Handwerksordnung zum 1.1.2004 war die hohe Ausbildungsleistung des Handwerks ein zentrales Argument, die im Falle einer überzogenen Deregulierung einbrechen würde. Folgt man der ökonomischen Theorie werden Handwerksbetriebe ausbilden, wenn der erwartete Nutzen die erwarteten Kosten überwiegt; Ausbildung wird zum unternehmerischen Erfolgsfaktor. Die zweimalige Befragung im Rahmen eines Projektes zur Regulierung auf dem deutschen Handwerksmarkt in Zusammenarbeit mit der Kreishandwerkschaft Lüneburg durchgeführt wurde, zeigt, dass vor allem die Ausbildungsaktivität selbst zu einer guten bis sehr guten wirtschaftlichen Lage füht bzw. diese verbessert. Allerdings ist dieser Effekt nach relativ kurzer Frist (zwei Jahre oder mehr) wieder verschwunden.

Wild zebra finches do not use social information from conspecific reproductive success for nest site choice and clutch size decisions

Information about the quality of local habitat can greatly help to improve an individual’s decision-making and, ultimately, its fitness. Nevertheless, little is known about the mechanisms and significance of information use in reproductive decisions, especially in unpredictable environments. We tested the hypothesis that perceived breeding success of conspecifics serves as a cue for habitat quality and hence influences breeding decisions (nest site choice and clutch size), using the zebra finch (Taeniopygia guttata) as a model species. Zebra finches breed opportunistically in the unpredictable, arid zone of Australia. They often inspect the nests of conspecifics, potentially to prospect on conspecific reproductive success, i.e., to collect social information. We conducted a clutch and brood size manipulation to experimentally create the perception of high and low quality areas. In six areas, clutch sizes of almost 300 zebra finch nests were either all increased (N = 3 areas) or reduced (N = 3 areas) throughout one breeding season. The number of breeding pairs and sizes of newly laid clutches were not significantly affected by the manipulated reproductive success of the areas. Thus, zebra finches did not use social cues for their reproductive decisions, which contrasts with findings of species in temperate zones, and could be an adaptation to the high unpredictability of their habitat. Even the personal experience of rebreeding birds did not directly affect their clutch size. Our study suggests that zebra finches employ a high level of opportunism as a key strategy for reproduction. Further, this is the first study to our knowledge using an experimental approach in the wild to demonstrate that decision-making in unpredictable natural environments might differ from decision-making in temperate environments with seasonal breeding

Begging calls provide social cues for prospecting conspecifics in wild zebra finches

Social information can spread fast and help animals adapt in fluctuating environments. Prospecting on the breeding sites of others, a widespread behavior, can help to maximize reproduction by, for instance, settling in the same area as other successful breeders. Previous studies have shown that successful broods have the highest number of prospectors and that they are visited most when offspring in nesting sites are already old, making the information more reliable. In this field study, we experimentally tested how prospectors are attracted to successful nest sites. We presented wild Zebra Finches (Taeniopygia guttata) with different visual or acoustic cues in nest boxes, simulating the presence of small or large clutches or broods. More Zebra Finches visited experimental nests that were associated with playback recordings of begging calls of large broods (7 chicks) as opposed to begging calls of small broods (3 chicks) and controls (white noise and silence). On the other hand, visual cues (nests with different numbers of eggs or rocks), representing nests at early stages, did not influence either the probability of visits, nor number or duration of visits. We present the first evidence that begging calls of chicks in the nest, a signal intended for kin communication, can also provide social information to unrelated prospecting conspecifics. This information could potentially be used for a fast initial assessment of the quality of a breeding site

Seismicity and active tectonics in the Alboran Sea, Western Mediterranean: Constraints from an offshore-onshore seismological network and swath bathymetry data

Seismicity and tectonic structure of the Alboran Sea were derived from a large amphibious seismological network deployed in the offshore basins and onshore in Spain and Morocco, an area where the convergence between the African and Eurasian plates causes distributed deformation. Crustal structure derived from local earthquake data suggests that the Alboran Sea is underlain by thinned continental crust with a mean thickness of about 20 km. During the 5 months of offshore network operation, a total of 229 local earthquakes were located within the Alboran Sea and neighboring areas. Earthquakes were generally crustal events, and in the offshore domain, most of them occurred at crustal levels of 2 to 15 km depth. Earthquakes in the Alboran Sea are poorly related to large-scale tectonic features and form a 20 to 40 km wide NNE-SSW trending belt of seismicity between Adra (Spain) and Al Hoceima (Morocco), supporting the case for a major left-lateral shear zone across the Alboran Sea. Such a shear zone is in accord with high-resolution bathymetric data and seismic reflection imaging, indicating a number of small active fault zones, some of which offset the seafloor, rather than supporting a well-defined discrete plate boundary fault. Moreover, a number of large faults known to be active as evidenced from bathymetry, seismic reflection, and paleoseismic data such as the Yusuf and Carboneras faults were seismically inactive. Earthquakes below the Western Alboran Basin occurred at 70 to 110 km depth and hence reflected intermediate depth seismicity related to subducted lithosphere

Early-life social environment predicts social network position in wild zebra finches

Early-life experience can fundamentally shape individual life-history trajectories. Previous research has suggested that exposure to stress during development causes differences in social behaviour later in life. In captivity, juvenile zebra finches exposed to elevated corticosterone levels were less socially choosy and more central in their social networks when compared to untreated siblings. These differences extended to other aspects of social life, with ‘stress-exposed’ juveniles switching social learning strategies and juvenile males less faithfully learning their father's song. However, while this body of research suggests that the impacts of early-life stress could be profound, it remains unknown whether such effects are strong enough to be expressed under natural conditions. Here, we collected data on social associations of zebra finches in the Australian desert after experimentally manipulating brood sizes. Juveniles from enlarged broods experienced heightened sibling competition, and we predicted that they would express similar patterns of social associations to stress-treated birds in the captive study by having more, but less differentiated, relationships. We show striking support for the suggested consequences of developmental stress on social network positions, with our data from the wild replicating the same results in 9 out of 10 predictions previously tested in captivity. Chicks raised in enlarged broods foraged with greater numbers of conspecifics but were less ‘choosy’ and more central in the social network. Our results confirm that the natural range of variation in early-life experience can be sufficient to predict individuals' social trajectories and support theory highlighting the potential importance of developmental conditions on behaviour

CCAFS site atlas – Lawra – Jirapa / Lawra

CCAFS site atlas for Lawra – Jirapa / Lawra, Ghana