Werner Konold

Effects of land-use history on size structure of holm oak stands in Spanish dehesas: implications for conservation and restoration

Dehesas , rangelands occupied by scattered oak trees and characterized by silvopastoral uses, cover about 3.1 million ha in south-western Spain. There is considerable debate about the long-term persistence of holm oak ( Quercus ilex ) populations in dehesas, since most stands are overaged and seedlings and saplings are sparse. The forest cycle has been disrupted in most dehesas. Regeneration has been inhibited since stands were opened for agriculture and grazing. Oak diameters from three land-use groups (young dehesa [YD], middle-aged dehesa [MD], and old dehesa [OD]) in Caceres Province, Spain, were compared. These groups differed in the age of the land-use system, i.e. time since the original Mediterranean forest was cleared. The dehesa systems were established about 80 (YD), 150 (MD) and 500 (OD) years ago. An analysis of 66 holm oak cross sections revealed a close correlation ( r 2 = 91.2%) between tree rings and diameters, so that diameter seems to be a reliable indicator of tree age. Nested analysis of variance showed significant variation in diameters between the land-use groups. There is generally a positive relationship between tree age and the age of agrosilvopastoral use of the dehesas. Sparse holm oaks in the dehesas are primarily remnants from the first forest cycle. Local differences in growth conditions (for example soil quality and tree density) contribute further significant diameter variation on a between-plot level. Diameter structure of abandoned dehesas showed two peaks and a high proportion of trees in the smallest size class. This indicates that the forest degradation process is reversible. An effective regeneration policy should promote a rotating 20- to 30-year set-aside of dehesa parcels.

Land manager attitudes toward management, regeneration, and conservation of Spanish holm oak savannas (dehesas)

Abstract Biological conservation in Spanish dehesas critically depends on the long-term persistence of a holm oak tree layer. Managers of private estates in Caceres province, Spain, were surveyed about their conservation attitudes and behavior, especially as regards the widespread regeneration failure of oak stands. The aim was to define land-user perspectives on oak conservation in dehesas as basis for the design of suitable oak regeneration programs. Dehesa estates are managed diversely for a variety of goals, with lamb and beef production predominating. Small operations (‘minifundios’) had significantly higher stocking levels than large operations (‘latifundios’). Results suggest that managers strongly appreciate oaks, both for income- and non-income-related motivations like the preservation of real estate value or family tradition. Concern about threats to oak stands like lacking regeneration, oak decline, or conversion in urban areas varied in intensity, but most managers expected major changes for the future. Statistical relationships were established between oak appreciation and socio-economic variables like age, land ownership, years the operation had been owned by the family, and use of oak products. The survey revealed great confusion about existing oak conservation regulations. For long-term support to be assured, policy should orient its efforts toward conservation incentive schemes, environmental education, and technical assistance.

Influence of cattle stocking rate on browsing of Norway spruce in subalpine wood pastures

In the Swiss Alps, 15% of Swiss mountain forests are grazed during summer, mainly by cattle. The forest laws of various Swiss cantons characterise forest grazing as a detrimental form of land use and stipulate that this grazing practice should be restricted. However, little is known about tree damage actually caused by cattle. Seven subalpine ranges in the Swiss Canton Grisons, grazed by cattle at different stocking rates, were investigated. The condition of naturally regenerated young trees (Picea abies (L.) Karst.) was assessed before and after the cattle grazing period. In order to characterise the influence of wild ungulates on the young trees during winter, the assessment of tree condition was repeated in the proximate spring. In total, 4% of the young trees were browsed on the apical shoot, 10% were browsed on lateral shoots, 13% of the trees showed other damage. The variation among ranges could almost completely be explained by the cattle stocking rate (livestock units per hectare). During winter, wild ungulates browsed 3 times as many young trees as the cattle during summer. The results suggest that cattle stocking rates on subalpine wood pastures should not exceed one livestock unit per hectare in order to avoid intensive browsing and other damage by cattle on young Norway spruces.

How is adaptation to climate change reflected in current practice of forest management and conservation? A case study from Germany

Climate change is expected to challenge forest management and nature conservation in forests. Besides forest species, strategies and references for management and conservation will be affected. In this paper, we qualitatively analysed whether forest conservation and management practice have already adapted to the impacts of climate change and to what extent those practices reflect the adaptation strategies dealt with in international peer-reviewed literature. To this end, we conducted thirteen in-depth interviews with forest practitioners (forest officers/forest district officers) in four regions in Germany. The interview regions were selected to represent the variation in tree species composition, forest ownership regimes and vulnerability to climate change. Although interviewees claimed to take climate change and adaptation strategies into account, in practice such strategies have as yet only occasionally been implemented. Our results suggest that strategies for adapting forest management to climate change are just in the early stages of development or supplement existing strategies relating to general risk reduction or nature-orientated forest management. The extent to which climate change adaptation strategies have influenced overall management varies. This variation and the lack of specific strategies also reflect the existing uncertainties about future changes in climate and about the capacity of forest ecosystems to adapt. We conclude that, in the face of climate change, forest management will have a major influence on future biodiversity composition of forest ecosystems. Hence, a framework for conservation in forests providing recommendations which also take into account the consequences of climate change needs to be developed.

Historic terraced vineyards: impressive witnesses of vernacular architecture

ABSTRACT English The history of viticulture has been widely studied in Europe. Knowledge of the landscape history of the viticulture once widely practised on terraced slopes is lacking, however. This paper contains an outline of the history of such vineyards. The forces driving the terracing of steep slopes are discussed, as are the advantages of building terraces and of using dry stone walls as retaining structures. The building fabric of historic terraced vineyards located in south-western Germany and in the Swiss canton of Valais was analysed employing a historical landscape analysis. The construction and function of the different elements of the vineyards, and their interactions, were a particular focus. Also presented are insights into how the building fabric may provide indications as to the owners and the construction history of such winegrowing areas. Finally, strategies for the preservation of these terraced vineyards, which are of great value from both a nature and a heritage conservation perspective, are presented, as are the benefits of continued research.

New approaches to support implementation of nature conservation, landscape management and cultural landscape development: experiences from Germany’s southwest

Worldwide natural landscapes are being replaced by human-dominated landscapes. A main feature is the human imprint that shapes and re-shapes these landscapes and reflects the socio-economic, political and cultural conditions as well as needs and values of a particular society at a given time. Some of these landscapes are considered cultural landscapes, in particular those that evolved over long periods of time and created biologically and culturally diverse landscapes with characteristic landscape elements. These cultural landscapes are considered worthy of protection. However, protecting or ‘freezing’ cultural landscapes at a particular point in time seems to be a contradictive goal since they have been continuously evolving based on their use and management. Therefore, maintaining and developing cultural landscapes or landscape elements in a way that they can contribute to their unique character whilst protecting internationally and nationally listed habitats and species appears to be a more sensible goal. We present Germany’s southwest, the state of Baden-Württemberg as a case study. We discuss the wide range of instruments that have been put in place to maintain and develop Baden-Württemberg’s cultural landscapes. We speculate about their future and argue that to maintain and develop these and other cultural landscapes around the globe require creative strategies that complement the conventional nature conservation and landscape management approaches. Although no panacea, regional development strategies that are developed from the bottom-up and are embedded in legal planning frameworks are likely to support management and development of cultural landscapes more effectively than any individual applications of the existing conventional approaches.

Successional changes of phytodiversity on a short rotation coppice plantation in Oberschwaben, Germany

To allow for information on successional changes in phytodiversity over time and space, as well as information on differences between clones and treatments, phytodiversity was monitored on a poplar short rotation coppice plantation in Oberschwaben, Southwest Germany, in four consecutive years. The investigated plantation was divided into two core areas, one planted with poplar clone Max4, the other with Monviso; each core area was divided into two blocks with alternating treatments: (i) irrigation and fertilization; (ii) irrigation; and (iii) no treatment. All vascular plant species of the ground vegetation were recorded in 72 permanent sampling plots of 25 m2 each during vegetation periods using the Braun-Blanquet scale. Results showed that total number of species increased in first 2 years and declined after harvest of the SRC-trees. Total vegetation cover decreased during the 4 years of study. Especially for the two clones there was an opposed trend: grass layer had a high cover on Monviso plots, but low cover on Max4 plots; herb layer the very reverse. However, there was no significant difference between the three treatments compared within each year. Perennial species were dominating over all years, as well as light-demanding species, but their proportion decreased steadily. Our results confirm the conclusion of previous studies which indicate that plant community succession takes place in ground vegetation of SRC and imply that species composition is age-dependent. The selection of clones for SRC can influence ground vegetation; some floristic changes for example caused by different treatments may be visible only when monitored over a longer period of time.

Naturschutz auf ehemaligen Truppenübungsplätzen: eine abschließende Betrachtung

Von den untersuchten Truppenubungsplatzen ist lediglich der 200 ha grose Schiesplatz des Truppenubungsplatzes Dauban vollstandig von militarischen Altlasten geraumt. Bei allen anderen Platzen wirkt sich die Kampfmittelbelastung zwar als Schutz fur die organismische Welt und deren Prozesse vor Eingriffen aus, bildet jedoch zugleich einen irrationalen und demoralisierenden Faktor fur die Bevolkerung der betroffenen Regionen. Dies resultiert zunachst aus den immensen Dimensionen, die sowohl die Kampfmittelreste als auch die damit verbundenen Entsorgungskosten erreichen (Beutler 2000). Nach uber zehn Jahren ist der Umfang der Munitionsbelastung noch nicht einmal hinreichend genau bestimmt und lokalisiert. Zuverlassige Sondierungen sind nicht in Aussicht, weil die damit verbundenen Kosten die Leistungsfahigkeit von Landern und Kommunen bei weitem ubersteigen. Wegen dieser undifferenzierten Perspektive bleiben partielle Losungen aus und das Altlastenproblem erscheint unuberwindbar.

Simple pond restoration measures increase dragonfly (Insecta: Odonata) diversity

Ponds are home to a diverse community of specialized plants and animals and are hence of great conservation concern. Through land-use changes, ponds have been disappearing rapidly and remaining ponds are often threatened by contamination and eutrophication, with negative consequences for pond-dependent taxa like amphibians or dragonflies (Odonata: Anisoptera and Zygoptera). Increasingly, restoration measures such as removal of shading terrestrial vegetation or submerged organic matter are implemented to counteract current threats, but how these measures affect the target taxa is rarely assessed. We tested if and how simple pond restoration measures affectionate diversity. We propose that pond restoration influences the light regime, which promotes aquatic and riparian vegetation important for different dragonfly life stages, thus increasing their diversity. Additionally, we assume that this changes dragonfly species composition between restored and unrestored ponds. We surveyed exuviae in the riparian and aquatic vegetation along the shore of 29 (12 restored, 17 unrestored) man-made ponds in southwest Germany and assessed environmental variables known to affect dragonfly diversity. We identified the cover of tall sedges and submerged macrophytes as the driving biotic variables for dragonfly diversity and species composition, with restoration measures affecting submerged macrophyte cover directly but tall sedges indirectly via available sunlight. This study demonstrates that simple restoration measures not only have a positive effect on overall dragonfly diversity, but also increase habitat suitability for several species that would otherwise be absent. We therefore propose dragonflies as a suitable flagship group for pond conservation.

Ziel des Vorhabens

Um die notwendigen naturschutzfachlichen Anpassungsstrategien umsetzen zu konnen, bedarf es eines diesen Strategien gerecht werdenden juristischen Konzepts, welches den Schutz von Arten und Lebensraumen auch bei sich andernden Klimabedingungen ermoglicht.