Franz Hermann Müschen (1774–1847)—ein Pomologe aus Mecklenburg auf der Höhe seiner Zeit

Zusammenfassung Der Pomologe Franz Hermann Müschen begann vor 200 Jahren mit der Prüfung und Verbreitung von Obstsorten in Mecklenburg. Er selbst beschrieb ab 1821 über 500 Sorten. Der Sohn Johann Georg Bogislav Müschen setzte das Werk seines Vaters fort und beschrieb 1876 weitere 317 Sorten. Beide betrieben eine konsequente Auslese, förderten lokale Sorten und schufen wesentliche Grundlagen für den Obstanbau in ihrer Heimat. Der Beitrag analysiert das Werk beider aus heutiger Sicht. Es werden auch Hinweise zu Müschens Rosenapfel gegeben. Franz Hermann Müschen wird anlässlich seines 230. Geburtstages am 9. Mai 2004 an seinem Wirkungsort Belitz mit einem 2-tägigen Symposium geehrt.     

Landscape changes and breeding bird assemblages in northwestern Portugal: the role of fire

Fire is a major driving force of landscape change in the Mediterranean region. The objectives of this paper were to explore the implications of landscape change and wildfires in a region of northwestern Portugal for the diversity of breeding birds. Land use cover for the years 1958, 1968, 1983 and 1995 was obtained from aerial photography for a study area of 3700 ha. Breeding bird assemblages in each of six land use categories were characterized in 1998 using point counts. The main landscape changes in the study area across the 40 years were a decrease in the area of agricultural land and low shrublands (respectively 29% and 48%) and an increase in forests and tall shrublands (both over 95%). Bird assemblages showed increased richness and diversity across the gradient: low shrublands tall shrublands conifer mixed deciduous agricultural areas. Many of the species with narrow niche breadth (specialists) were associated with agricultural areas and deciduous forests. In spite of the low diversity of burned areas (mostly shrublands) a few specialist species depend on this habitat. Thus, the current fire regime probably contributes to maintaining bird diversity at the landscape level. There was an inverse relationship between landscape diversity and estimated bird diversity across the last 40 years. Landscape management actions to preserve bird diversity should focus on the maintenance of agricultural land and deciduous forests. In parallel, a wider use of prescribed burning and grazing is suggested. This would contribute to maintaining low shrublands in the landscape, useful both as an habitat for some bird species and as fuel breaks for preventing the occurrence of large wildfires.     

Allochthonous ecosystems

In extreme deserts with precipitation of less than 10–20 mm/yr, biocoenoses occur which are void of producers but show ecosystem functions such as food chains and energy flow. Since they are fed by the importation of allochthonous organic material the term allochthonous ecosystems is proposed to designate these systems. The application of this term to other incomplete ecosystems without producers is discussed.     

A case study of forest change in the Swiss lowlands

This paper presents a regional case study of forest development and the history of forest use and management in the north-eastern lowlands of Switzerland during the 19th and 20th centuries. The analysis draws on historical documents related to forestry to consider the following aspects of forest change: forest types, growing stock, trees species composition and non-timber forest uses. Based on the data presented, three overlapping periods of forest use and management can be discerned. The period of traditional multiple use lasted until the second half of the 19th century. From the mid 19th to the mid 20th century, a period of primacy of timber production occurred. During the 20th century, the period of modern multi-impact management has developed. For these three periods, groups of main actors, their needs and interests, and how they were causing the changes in the aspects under study were defined. This procedure of defining periods and the respective groups of main actors is a critical link between landscape ecology and history, as changes in demands of the society can be directly linked with changes in land-use and land-cover.     

Changes in anthropogenic impervious surfaces,precipitation and daily streamflow discharge: a historical perspective in a mid-atlantic subwatershed

Aerial photography provides a historical vehicle for determining long-term urban landscape change and, with concurrent daily streamflow and precipitation records, allows the historical relationship of anthropogenic impervious surfaces and streamflow to be explored. Anthropogenic impervious surface area in the upper Accotink Creek subwatershed (near Annandala, Virginia, USA) was mapped from six dates of rectified historical aerial photography ranging from 1949 to 1994. Results show that anthropogenic impervious surface area has grown from approximately 3% in 1949 to 33% in 1994. Coincident to this period, analysis of historical mean daily streamflow shows a statistically significant increase in the streamflow discharge response (per meter of precipitation) associated with normal and extreme daily precipitation levels. Significant changes were also observed in the frequency of daily streamflow discharge at given volumes above and below the historical daily mean. Simultaneously, the historical magnitude, frequency and pattern of precipitation values 0 mm, 6.0 mm and 35.0 mm show either no statistically significant change or influence on streamflow. Historical changes in streamflow in this basin appear to be related to increases in anthropogenic impervious surface cover. Historical aerial photography is a viable tool for revealing long-term landscape and ecosystem relationships, and allows landscape investigations to extend beyond the temporal and spatial constraints of historical satellite remote sensing data.This revised version was published online in May 2005 with corrections to the Cover Date.     

Spatial theory in early conservation design: examples from Aldo Leopold’s work

Aldo Leo­pold is well known in North America as a conservationist, author, and promoter of the Land Ethic. Although Leo­polds work is rarely included in the realm of landscape ecology, he left several illustrations of an early spatial theory for conservation. While European geographer Troll published the term landscape ecology in 1939, Leo­pold was discovering the role of spatial configuration in European working landscapes, and began to apply the landscape ecology concepts to wildlife management and cooperative conservation in the US. With his own spatial language he wrote, mapped, and applied elements of pattern, process, and connectedness in the landscape. In this perspective piece I use three examples from Leo­polds work to demonstrate his contribution to spatial theory in early conservation design. First, this paper deciphers spatial elements conveyed through Leo­polds writing, drawing, and teaching in the early 1930s. Second, I re-interpret Leo­polds observations of the spatial design of remises from his visit to Silesia, Europe. Third, I show how the lessons from Silesia were applied to a landscape in Wisconsin, USA, involving both farmers and townspeople in cooperative implementation of a remise system. Collectively, a new perspective emerges on the early dialogue of landscape ecology and conservation across continents.This revised version was published online in May 2005 with corrections to the Cover Date.     

Deciduous forest and resident birds: the problem of fragmentation within a coniferous forest landscape

Six species of resident birds were censused in patches of deciduous forest within a coniferous forest landscape in south central Sweden. Here, the forests have been subjected to active forestry for a long time, but with recently increased intensity. Although the forest cover is more or less continuous in this landscape, mature deciduous forest is now a rare element compared with the untouched forest.All censused patches were similar with regards to size, proportion and amount of deciduous trees, but were either isolated in the coniferous forest (isolated patches) or near to other deciduous patches (aggregated patches). We concentrated on six species of resident birds, with moderate area requirements, that are tied to deciduous forest and whose ecology is well-known. The Nuthatch and the Marsh tit, which both show strict year-round territoriality and have a restricted dispersal phase, were significantly more likely to be found in aggregated than in isolated patches. No effect was found for the Great tit and the Blue tit, which are less territorial outside the breeding season and have a longer dispersal phase. Moreover, the Great tit is less specialized on deciduous forest than the other species. Also, the Long-tailed tit was negatively affected by isolation, which may be due to restricted dispersal and to larger area requirements of this flock-territorial species. The Hazel grouse, finally, was not affected, but this larger bird probably uses the forest in a different way from the smaller species.Our study clearly shows that fragmentation of one type of forest (deciduous) within another can have serious detrimental effects on forest-living species and raises important issues for forest management practices and conservation within a forest landscape.     

Landscape graphs: Ecological modeling with graph theory to detect configurations common to diverse landscapes

In view of the bewildering diversity of landscapes and possible patterns therein, our objectives were to see if a useful modeling method for directly comparing land mosaics could be developed based on graph theory, and whether basic spatial patterns could be identified that are common to diverse landscapes. The models developed were based on the spatial configuration of and interactions between landscape elements (ecosystems, land uses or ecotopes). Nodes represented landscape elements and linkages represented common boundaries between elements. Corridors, corridor intersections, and the matrix were successfully incorporated in the models. Twenty-five landscape graphs were constructed from aerial photographs chosen solely to represent a breadth of climates, land uses and human population densities. Seven distinctive clusters of nodes and linkages were identified and common, three of which, in the forms of a spider, necklace and graph cell, were in >90% of the graphs. These represented respectively the following configurations of patches, corridors and matrix: (1) a matrix area surrounding or adjoining many patches; (2) a corridor bisecting a heterogeneous area; and (3) a unit in a network of intersecting corridors. The models also indicated that the connectivity or number of linkages for several common elements, such as fields and house clearings, was relatively constant across diverse landscapes, and that linear shaped elements such as roads and rivers were the most connected. Several additional uses of this graph modeling, including compatibility with systems dynamics models, are pinpointed. Thus the method is useful in allowing simple direct comparisons of any scale and any landscape to help identify patterns and principles. A focus on the common and uncommon configurations should enhance our understanding of fluxes across landscapes, and consequently the quality of land planning and management.     

Eintritt für Selbstpflücke, ein Kontinent ohne Frigopflanzen und ‘Elsanta‘

Zusammenfassung Die im Wachstum begriffene australische Erdbeerindustrie ist geprägt durch optimale Klimabedingungen und einfachen Zugang zu den Ressourcen, hohe Intensivierung und — wie in Kalifornien — hohe Erträge über 30 t/ha. Der Markt ist fast autark, Im- und Exporte frischer Erdbeeren spielen keine Rolle. Mit einem derzeitigen Produktionsvolumen von 40.000 t/Jahr auf ca. 1.300 ha wird eine Ausweitung auf 71.000 t bis zum Jahre 2008 angestrebt. Dies entspricht — bei ca. 20 Mio. Einwohnern Australiens — einer Steigerung des Erdbeerkonsums von 2,0 kg auf ca. 2,7 kg/Kopf und Jahr im Jahr 2008. Der gegenwärtige Erdbeerkonsum in Deutschland liegt bereits bei ca. 2,7 kg/Kopf und Jahr, wobei die Erdbeerimporte von ca. 120.000 t die Eigenproduktion von ca. 100.000 t auf 10.420 ha Anbaufläche — im Gegensatz zu Australien — übersteigen. Die drei australischen Hauptanbaugebiete konzentrieren sich auf Queensland im Nordosten, Perth im Westen und Victoria im Südosten Australiens. Der überwiegend einjährige Anbau erfolgt mit 45.000–66.000 Grünpflanzen/ha als Einzel- oder Doppelreihe in Dammkultur und Mulchfolie mit integriertem Fertigationsschlauch. Nach telefonischem Verkauf erfolgt die Lieferung im Kühl-LKW direkt an die Supermärkte oft weit entfernter Großstädte. Als tagneutrale Erdbeersorten dominieren mit 90% amerikanische Sorten wie Selva, Camarosa und Camino Real aus Kalifornien sowie Sweet Charlie und Festival aus Florida. Interessante Neuzüchtungen aus dem Jahre 2003 sind Rubygem, Sugarbaby, Brighteyes und Harmony aus Queensland als Kurztagssorten. Zusammen mit tagneutralen Sorten aus dem südlichen Züchtungsprogramm in Victoria stieg ihr Marktanteil in den letzten drei Jahren von 8% auf 10%. Primäre Zuchtziele des nördlichen Züchtungsprogramms in Queensland sind Kurztagssorten mit frühem Reifebeginn und hohem Ertrag über 1,2 kg/Pflanze. Das südliche Züchtungsprogramm um Victoria zielt dagegen sowohl auf Kurztagssorten als auch Tagneutralität sowie eine zusätzlich lange Ernteperiode über mindestens 10 Wochen. Während die Zuchtziele der äußeren Fruchtqualität wie Fruchtgröße, Fruchtfestigkeit und Glanz mit denen Deutschlands übereinstimmen, unterscheiden sich die der inneren Fruchtqualität wie süßer Geschmack bei gleichzeitiger Säurearmut und hoher Fruchtfleischfestigkeit.     

Erfolgreiche Bekämpfung des Apfelschorfs mit Kalziumhydroxid

Zusammenfassung In einer 12-jährigen Apfelanlage mit den Sorten Elstar, Fiesta, Golden Delicious, Jonagold und Kent wurde im Jahre 2004 die Schorfbekämpfung durch Überkronenberegnung mit Suspensionen von Kalziumhydroxid (5 g/l) durchgeführt. Im Zeitraum 7. April bis 30. September 2004 wurde insgesamt 62-mal für 15 min beregnet. Drei verschiedene Zeitpunkte der Behandlungen wurden getestet. Bei Behandlung A wurde mit der Beregnung begonnen, wenn nach Mills 100% Infektion erreicht waren. Bei den Behandlungen B und C wurde die Beregnung 6 bzw. 20 h später gestartet. Bei den nicht behandelten Kontrollen waren zum Zeitpunkt der Ernte bei Golden Delicious 30% und bei Jonagold 23% der Früchte mit Schorf befallen. Die Kontrollbäume der anderen Sorten hatten keinen Fruchtschorf. Die Früchte der drei Behandlungen waren bei der Ernte und nach einer 7,5-monatigen Lagerung im Kühllager oder im ULO-Lager frei von Schorf. Die Bonitur auf Schorfbefall der Blätter erfolgte zum Zeitpunkt der Ernte an 3 Langtrieben pro Baum mit je etwa 20–25 Blättern. Bei der Ernte im September/Oktober wurden bei allen Kontrollen Schorfflecken gefunden. Die Extreme reichten von 20 bis fast 60% befallene Blätter. Die Blätter der Langtriebe aller Behandlungen waren schorffrei. Bei den Behandlungen hatten die Blattunterseiten im Mittel bis zu 15% Schorfläsionen. Das liegt vermutlich daran, dass bei der Überkronenberegnung die Blattunterseiten nicht vollständig benetzt wurden. Die Ergebnisse zeigen, dass Schorfbekämpfung mit Überkronenberegnung von Kalziumhydroxid möglich ist.     

Using fractal analysis to assess how species perceive landscape structure

To develop a species-centered definition of landscapes, I suggest using a fractal analysis of movement patterns to identify the scales at which organisms are interacting with the patch structure of the landscape. Significant differences in the fractal dimensions of movement patterns of two species indicate that the species may be interacting with the patch structure at different scales. Fractal analysis therefore permits comparisons of landscape perceptions of different species within the same environment.I tested the utility of this fractal application by analyzing the movement patterns of three species of acridid grasshoppers (Orthoptera) in a grassland mosaic. The largest species moved up to 6 times faster than the two smaller species, and species exhibited different responses to microlandscape structure within 25-m² plots. Further, the largest species exhibited different responses to microlandscape structure in two pastures subjected to different intensities of cattle grazing. This species thus is able to integrate information on landscape structure at broad spatial scales. Fractal analysis of movement patterns revealed that the two small species had significantly more tortuous patterns than the larger species, which suggests that these species are interacting with patch structure at a finer scale of resolution than the large species. Fractal analysis can be used to identify the perceptive resolution of a species; that is, the spatial grain and extent at which they are able to perceive and respond to heterogeneity. Analysis of movement patterns across a range of spatial scale may reveal shifts in fractal dimension that reflect transitions in how species respond to the patch structure of the landscape at different scales.     

A proximity-based approach to assessing habitat

Planning for either a single species, multiple species, or ecosystems is greatly dependent on spatial interactions in the landscape. Problems exist for evaluating wildlife habitat changes over large ranges of space and time. This paper illustrates the use of Geographic Information Systems (GIS) to evaluate habitat for a single species, ruffed grouse (Bonasa umbellus), following a time series of forest harvests. A habitat suitability model for ruffed grouse is utilized on a two-township study area in north-central Minnesota to assess the habitat suitability changes over time using an even-aged area-control harvesting plan. The results are presented as a habitat quality change map and a contingency table, representing the movement of habitat class areas between time periods resulting from the proposed harvesting. We developed a neighborhood definition to allow for spatially varying habitat values. This work illustrates the ability to look ahead and around in estimating the impact on wildlife habitat resulting from alternative future management activities.Now with the U.S. Forest Service, Sitka, AK 99835.     

Bird assemblages in forest fragments within Mediterranean mosaics created by wild fires

The role of habitat heterogeneity as a key factor in determining species pools in habitat mosaics has been acknowledged, but we still know little on the relative importance of the different ecological processes acting within such complex landscapes. We compared species richness and distribution in forest fragments imbedded in shrub-lands to those in continuous forests or in continuous shrublands. We examined the consistency of our data with the predictions of two hypotheses: 1) the Habitat fragmentation hypothesis which states that fragmentation has negative effects on the species from the original continuous habitat; 2) the Habitat supplementation /complementation hypothesis which stipulates that the presence of a matrix habitat around the fragments will mitigate negative effects on the species from the original habitat (supplementation) or allow the presence of species that depend on the presence of both the fragment and matrix habitats (complementation). We show that: 1) species richness in forest fragments did not differ from species richness in segments of continuous forests of equal area; 2) the bird community of forest fragments got impoverished in some forest species but a higher proportion of species common in continuous forests were not affected by fragmentation; 3) fragment communities had a significant proportion of common species that were scarce in, or absent from both continuous forests and shrublands. While, a few forest species supported predictions from the fragmentation hypothesis, occurrence patterns observed in several other species were consistent with either the supplementation or the complementation hypotheses. Our results suggest that there is no single hypothesis that properly captures the consequences of a shift from continuous forests to a mosaic of forest fragments and shrublands and that different ecological mechanisms act in conjunction to determine species pools in habitat mosaics. Habitat heterogeneity at a local scale appears a key factor in maintaining bird diversity in fire driven Mediterranean landscapes.     

Estimating dispersibility of Acer,Fraxinus and Tilia in fragmented landscapes from patterns of seedling establishment

Relative dispersibility of Tilia americana L., Acer saccharum Marsh. and Fraxinus pennsylvanica Marsh, was inferred from the ratio among species-specific regression coefficients () computed from seedling density-distance plots. Density counts were made in spatially-uniform old fields adjacent to single seed sources or monotypic fencerows. Resultant seedling shadow curves approximate the negative exponential form expected for many seeds (log y=a–X). This basic curve shape fit species of differing dispersibility, dispersal under a range of wind directions and one-year-old or all-aged cohorts. The ratios of were 1:2.6:3.2 for Tilia, Acer and Fraxinus, respectively, in order of increasing dispersibility. Vegetation patches isolated from seed sources by several hundred meters or more should have extremely low input of seeds, especially Tilia and Acer.The finding that Fraxinus disperses farther than Acer was unexpected, since the samaras of the former have faster terminal velocities. The relationship can be explained by better performance of Fraxinus samaras in the stronger winds experienced by trees in open landscapes, poorer formation of the samara abscission layer, and release of samaras following leaf abscission and during the winter when winds are the strongest. Both the samara plan and dispersal phenology need to be considered in estimating relative dispersibility among species.     

Quantifying functional connectivity: Experimental evidence for patch-specific resistance in the Natterjack toad (Bufo calamita)

Despite the importance assigned to inter-patch movements in fragmented systems, the structure of landscape between suitable habitat patches, the matrix, is often considered as to be of minor interest, or totally ignored. Consequently, models predicting metapopulation dynamics typically assume that dispersal and movement abilities are independent of the composition of the matrix. The predictions of such models should be invalided if that crucial assumption is unverified. In order to test the hypothesis of a patch-specific resistance, we led an experimental study to assess the matrix effects on the movement ability of juvenile Natterjack toads (Bufo calamita). The movement behaviour of first year toadlets, the dispersal stage in this species, was investigated in an arena experiment. Toadlet mobility was assessed in five landscape components that were mimicked in the lab: sandy soil, road, forest, agricultural field, and pasture. We analysed several movement components including move length, speed, efficiency and turning angle distribution. Our results showed that movement ability was strongly affected by the land cover, even if body size modulated the behavioural responses of toadlets. Performances were the best in the arenas mimicking sand and roads, and the worst in the forest arena, toadlet moves being three to five times less effective in the latter. The mobility was intermediate in the two other arenas. We propose here a new method to quantify functional connectivity, based on quantitative estimates of relative values for resistance of landscape components. This method offers a reliable alternative for resistance value estimates to subjective expert advice or inference from genetic population structure.     

Quantifying functional connectivity: Experimental evidence for patch-specific resistance in the Natterjack toad (Bufo calamita)

Despite the importance assigned to inter-patch movements in fragmented systems, the structure of landscape between suitable habitat patches, the matrix, is often considered as to be of minor interest, or totally ignored. Consequently, models predicting metapopulation dynamics typically assume that dispersal and movement abilities are independent of the composition of the matrix. The predictions of such models should be invalided if that crucial assumption is unverified. In order to test the hypothesis of a patch-specific resistance, we led an experimental study to assess the matrix effects on the movement ability of juvenile Natterjack toads (Bufo calamita). The movement behaviour of first year toadlets, the dispersal stage in this species, was investigated in an arena experiment. Toadlet mobility was assessed in five landscape components that were mimicked in the lab: sandy soil, road, forest, agricultural field, and pasture. We analysed several movement components including move length, speed, efficiency and turning angle distribution. Our results showed that movement ability was strongly affected by the land cover, even if body size modulated the behavioural responses of toadlets. Performances were the best in the arenas mimicking sand and roads, and the worst in the forest arena, toadlet moves being three to five times less effective in the latter. The mobility was intermediate in the two other arenas. We propose here a new method to quantify functional connectivity, based on quantitative estimates of relative values for resistance of landscape components. This method offers a reliable alternative for resistance value estimates to subjective expert advice or inference from genetic population structure.     

Scale dependence of tree abundance and richness in a tropical rain forest,Malaysia

Abundance and richness are the two fundamental components of speciesdiversity. They represent two distinct types of variables of which the formerisadditive when aggregated across scales while the latter is nonadditive. Thisstudy investigated the changes in the spatial patterns of abundance andrichnessof tree species across multiple scales in a tropical rain forest of Malaysiaandtheir variations in different regions of the study area. The results showedthatfrom fine to coarse scales abundance had a gradual and systematic change inpattern, whereas the change in richness was much less predictable and ahotspot in richness at one scale may become acoldspot at another. The study also demonstrated that differentmeasures of diversity variation (e.g., variance and coefficient of variation)can result in different or even contradictory results which further complicatedthe interpretation of diversity patterns. Because of scale effect the commonlyused measure of species diversity in terms of unit area (e.g.,species/m²) is misleading and of little use in comparing speciesdiversitybetween different ecosystems. Extra care must be taken if management andconservation of species diversity have to be based on information gathered at asingle scale.This revised version was published online in May 2005 with corrections to the Cover Date.     

Für eine Verdopplung der Ca-Gehalte der Äpfel sind auch unter günstigen Bedingungen mindestens 12 Spritzungen mit Kalziumchlorid erforderlich

Zusammenfassung Siebenjährige Apfelbäume der Sorten Elstar, Gala, Karmijn de Sonnaville, Pinova und Pilot wurden 2003 von Juni bis September 12-mal mit 400 l/ha CaCl₂-Lösungen gesprüht. Kontrollen (Fu) waren Bäume, die nur mit Fungiziden (Discus, Dithane Ultra oder Kumulus) behandelt wurden. Bei den Behandlungen FuCa wurde den Fungiziden CaCl₂ (ansteigend von 5–25 g/l) zugegeben. Die Behandlungen FuCaTe enthielten zusätzlich das Netzmittel Plantacare 1200 UP, um die Benetzung der Früchte (Oberflächenspannung 29–30 mN/m) zu verbessern. Die Ca-Konzentrationen in den Kontrollfrüchten (Schale plus 5 mm Fruchtfleisch) variierten von 3,6 (Elstar) bis 9,0 mg/100 mg Frischsubstanz (Pilot). Durch die Fruchtdüngung (FuCa) stiegen die Konzentrationen auf 6,3 bzw. 13,3 mg/100 g Frischsubstanz (FS). Zugabe des Netzmittels (FuCaTe) erhöhte die Ca-Gehalte weiter auf 6,8 bzw. 14,9 mg/100 g FS. Bezogen auf die Behandlung Fu entspricht das einer Erhöhung der Ca-Konzentrationen der Früchte auf 163 bzw. 193%. Der Tensideffekt auf die Ca-Konzentrationen der Früchte wird auf die schnellere Penetration des CaCl₂ infolge besserer Benetzung zurückgeführt, da ein Einfluss auf die Retention der Spritzbrühe ausscheidet. Von der applizierten Ca-Dosis in Höhe von 26 kg/ha wurden nur 2,3 kg in den Früchten (50 t/ha) wieder gefunden, was einer Wiederfindungsrate von 8,8% entspricht. Die beobachtete Erhöhung der Ca-Konzentrationen der Früchte durch 12 Spritzungen dürfte in der Nähe des maximal Möglichen liegen, da die Witterungsbedingungen günstig und die Ca-Konzentrationen der Spritzbrühen hoch waren.