Woodland Structure Research Articles

Driving forces of stability and change in woodland structure: A case-study from the Czech lowlands

This paper presents how long-term socioeconomic processes influenced the management and structure of a lowland ancient wood in the south-eastern Czech Republic from the 14th century to the present. The analysis draws on a wide range of historical documents to establish that the size, management and structure of Děvín Wood was remarkably stable throughout the study period except for the last 60 years. It is argued, however, that the long-term stability of woodland management and structure contrasts with the multiple changes that can be observed in the driving forces behind this stability. Four kinds of driving forces are distinguished (business, need for firewood, nature conservation and forestry policy), whose various combinations maintained the coppice structure of the Wood for six centuries. It is concluded that landscape ‘stability’ and ‘change’ are highly context-dependent, and that socioeconomic driving factors are a crucial link between forest ecology and history, representing a means to understand and control current ecosystems and future changes. The paper also demonstrates that in European historical ecology it is necessary to integrate qualitative and quantitative sources in order to study periods before ca. 1800 AD, i.e. the appearance of modern quantitative sources, because societal processes have exerted their influence on landscapes much longer than 200 years.

Integrating multiple landscape-scale drivers in the lichen epiphyte response: climatic setting, pollution regime and woodland spatial-temporal structure

Aim To quantify the role of multiple biodiversity drivers – pollution, woodland structure and climate – controlling lichen epiphyte composition and diversity. Location Scotland, north-west Europe. Methods Four compatible datasets were assembled: site-scale species distribution data (response) and base-line modelled data on climate, pollution loads and extent of old-growth woodland (explanatory variables). First, partial-canonical correspondence analysis was used: (1) to compare the importance of environmental variables to pure spatial effects and (2) to partition the importance of environmental variables in explaining species composition. Secondly, patterns of species richness were investigated using multiple least-squares regression. Results Old-growth woodland was the most important control of species richness. Pollution was the most important explanatory variable for species composition. The impact of pollution on composition (and to a lesser extent on richness) is explained: (1) By recovery of lichens with declining SO2 pollution, although with epiphyte composition shifted by the recent effects of N-pollution and (2) By the limited spatial extent of severe pollution, and generally low-to-moderate pollution loads across our study area, combined with the positive effect of old-growth woodland extent in controlling species richness. The effect of climate and old-growth woodland on species composition covaried, supporting an interaction between habitat quality and climatic setting, which may be important in understanding the epiphyte response to climate change. Conclusions Advances in conservation planning will likely require an integrated approach to understanding simultaneous effects of multiple drivers, providing opportunities for integrated management strategies. Our study provides a preliminary example of this approach by combining three key biodiversity drivers into a single framework for lichen epiphytes. Thus, reducing pollution loads may make old-growth woodland that currently exists in a polluted landscape available for colonization, thereby extending the available habitat for epiphytes, and facilitating an effective species response to climate change.

Do Polylepis australis trees tolerate herbivory? Seasonal patterns of shoot growth and its consumption by livestock

Browsing is one of the main factors determining survival, growth rate, woodland structure, and distribution of the high mountain tree Polylepis australis. This species has a substantial regrowth capacity, which may function as a mechanism to tolerate herbivory, but it is unknown to what extent it may compensate for the impact of herbivory. In 15 low-density tree stands subject to exclusion, moderate, and heavy livestock pressure, we selected 12 P. australis individuals <2 m tall, tagged four new shoots per tree and measured shoot length every month during a year. At the stand and at the tree level, we analyzed monthly dynamics of growth and browsing, and the annual output in terms of total browsing and total gross and net growth (not discounting and discounting consumption, respectively). In addition, we assessed the influence of stand, tree and microsite characteristics on growth and browsing patterns. Polylepis australis fully compensated for herbivory in terms of shoot gross growth at moderate, but not at heavy livestock pressure. In terms of net growth, this species did not fully compensate for herbivory at any stocking rate. We found a strong coupling between browsing and growth along the year, suggesting that regrowth attracts browsing, and browsing promotes regrowth. At the stand level, annual gross growth was not affected by habitat characteristics, while at the tree level, annual gross growth decreased on more rocky microsites for browsed but not for unbrowsed trees. We concluded that stocking densities should be limited to allow for a reasonable annual net growth, as its nitrogen rich leaves are a valuable food resource and P. australis forests provide important ecosystem services.

A continuous Holocene beetle record from the site Stavsåkra, southern Sweden: implications for the last 10 600 years of forest and land use history

AbstractBeetle remains from a small bog in southern Sweden contribute information concerning the forest history of the study area. The study shows that beetles are valuable indicators of woodland structures such as openness, field vegetation, presence of dead wood and disturbance factors such as climate change, fire regimes, grazing and land use. The early Holocene, ca. 8600–6450 cal. BC, was characterised by open, pine‐dominated woodlands maintained by fire and grazing disturbances. The changes in the wetland fauna, between 8600 and 7500 cal. BC, correlate well with low lake levels in southern Sweden. During the mid Holocene, ca. 6450–2400 cal. BC, the woodlands were relatively dense, with few openings in the canopy. Around 4200 cal. BC, there was a shift to a dominance of deciduous trees. Fire and grazing pressures were particularly low. Numbers of aquatic and hygrophilic beetles indicate dry conditions between ca. 5000 and 3000 cal. BC. During the late Holocene, ca. 2400 cal. BC to present, the woodlands opened up mainly through increased land use. The main disturbance factors were fire and grazing. The beetles indicate the formation of heather‐dominated heathland around 800 cal. BC. Copyright © 2008 John Wiley &amp; Sons, Ltd.This article was published online on 23 December 2008. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected (5 August 2009).

Forty-year changes in the canopy and the understorey in Wytham Woods

Summary This study investigates changes in the composition of part of Wytham Woods (southern England), between the 1960s and 2007. The study focussed on an area of ~ 4 ha shown on a 1961 aerial photograph, part former open common, part ancient woodland. Changes in the canopy appearance were considered using a recent (1999) aerial photograph. Trees and shrubs were recorded in a 200 × 10 m transect to illustrate current stand structure across the historic management division. In the north-east corner of the area, tree diameters and understorey abundance from 1968 were compared with the current stand structure. Since the 1950s, Fraxinus excelsior has colonized the open areas. Tree growth was estimated from comparison of diameter/girth measurements from 1968 and 2007. F. excelsior diameter increment was greater than that of Acer pseudoplatanus and both showed faster growth than Quercus robur . Some canopy trees died, but no large gaps formed in the closed woodland. The abundance of understorey stems declined. The current stand structure refl ects effects of past management, browsing pressure and climatic stresses over the last four decades. Multiple causes of change are probably commoner than single factors in explaining woodland structure.

Bat Response to Woodland Restoration within Urban Forest Fragments

In urban environments, woodland areas are typically fragmented and subject to invasive species encroachment, woody overgrowth, and natural succession. In response to negative impacts, conservationists and land managers have implemented restoration strategies to enhance the integrity of woodlands. Because woodland habitat is important for bats (Order Chiroptera), alterations to forest structures may affect how bats utilize forest fragments in urban environments. We evaluated relationships among restoration efforts, microhabitat characteristics and overall bat activity, and interspecific variation among bats in response to woodland characteristics. We monitored bats in nine woodland forest preserves representing various stages of restoration within the Chicago metropolitan area in 2004 and 2005. Overall bat activity was positively related to prescribed burning, invasive species removal, and small tree density (7.7-20 cm dbh) and inversely related to shrub density and clutter at 0-6 m heights. There was interspecific variation in response to alterations in woodland structure, with Lasiurus borealis (L. borealis) positively associated with small and medium (20.1-33 cm) tree densities and inversely related to clutter at 0-9 m; Myotis spp. positively associated with canopy cover, clutter at 6-9 m, and small and medium tree densities; and Lasionycteris noctivagans (L. noctivagans) positively associated with more open forests. Eptesicus fuscus (E. fuscus) activity was not strongly associated with any measured vegetation variable. Our results demonstrate bats positively respond to some forms of woodland restoration in urban landscapes. However, species-specific responses to vegetation differed and should be taken into consideration when developing management plans.

Changes in the structure and composition of miombo woodlands mediated by elephants (Loxodonta africana) and fire over a 26‐year period in north‐western Zimbabwe

AbstractChanges in structure and composition of miombo woodlands mediated by elephants and fire were studied in 26‐year‐old permanent transects established in 1972 in north‐western Zimbabwe. Elephants caused 48% decline in proportions of large trees (&gt;11 cm diameter), significant reductions (30.9–90.9%) in tree heights, reductions in stem areas (43.5%) and densities (2.5%) of all trees. There were increases in proportions of small trees (64.8%), shrub canopy volumes (271%) and shrub densities (172%). These increases are attributed to natural recruitment because of longer fire‐free periods and reduction of tree suppression effects on lower strata as a result of elephant‐induced tree declines. Frequencies of occurrence of most species dropped by 28–89.6%. Brachystegia boehmii was replaced by Pseudolachnostylis maprouneifolia as the most dominant tree, largely because of high elephant preference for Brachystegia boehmii. A new suite of species, dominated by Combretaceae, increased in dominance resulting in local floristic changes. Reductions in old elephant (33.4%), old unknown (89.9%) and new elephant (13.7%) damage suggest that elephant occupancy of miombo woodlands has declined, possibly because of limited availability of preferred browse species. This study clearly shows that elephants and fire have contributed significantly to the changes in miombo woodlands in the area.

Phytogeography and Floristics of Pinyon-Juniper Woodlands in Northern Arizona

This study assesses the floristic diversity and affinities of pinyon-juniper (PJ) woodlands in northern Arizona at 2 different scales: regionally within the context of North American floristic patterns and locally within the 2500m elevation gradient of the San Francisco Volcanic Field (SFVF). An analysis based upon 245 North American floras indicates that the PJ woodlands of the SFVF share strong affinities with the adjacent Colorado Plateau and Apachian floristic elements but also show high floristic similarity to the Great Plains. Data suggest that mid-elevation woodlands of the Colorado Plateau share floristic affinities with the Great Plains that are as strong as or stronger than those shared with the Great Basin. A geostatisical analysis provides a spatially explicit depiction of these findings. A comparison of species occurrences between 6 adjacent biotic communities in northern Arizona reveals that the PJ woodlands host the most distinctive flora among local life zones. Despite what their simple woodland structure may suggest, PJ woodlands of the SFVF host a moderately species-rich flora. This study suggests that the floras of PJ woodlands vary in significant and important ways across the range of PJ woodlands in western North America.

Quantifying the role of multiple landscape-scale drivers controlling epiphyte composition and richness in a conservation priority habitat (juniper scrub)

Recent concern over human-induced climate warming has activated bioclimatic research projecting the species-response to climate change scenarios. However, climate change is one of a range of human-induced environmental drivers controlling biodiversity, and for many species should be considered together within a framework of relevant stresses and threats. This paper critically assesses the sensitivity of epiphyte assemblages to regional gradients in climate, pollution regime and landscape-scale habitat structure (woodland extent and fragmentation). We examine lichen epiphytes associated with juniper scrub (a conservation priority habitat in Europe), sampled across a network of protected sites in Britain (Special Areas of Conservation). Results point to significant differences in associated epiphyte diversity between conservation priority sites. Historic woodland structure was identified as of greater importance than present-day woodland structure in controlling species composition and richness, pointing to an extinction debt among lichen epiphytes. Climatic setting was important in controlling species composition, but not species richness. However, we demonstrate that pollution regime exerts the dominant controlling force for epiphyte assemblages across regional gradients. As a corollary, we caution that for many species groups – for example those sensitive to pollutants, or landscape structure – an exclusive focus on climate is restricting, and that climate change models should expand to include a range of multiple interacting factors.

GIS-Based Modeling of Pinyon–Juniper Woodland Structure in the Great Basin

Abstract Pinyon–juniper woodlands are a dominant vegetation type across the Intermountain West, covering an estimated 30 million ha. Increases in density, cover, and aerial extent over recent decades have been associated with altered fire regimes, tree mortality, and reduced understory productivity. In our study we sought to determine how environmental factors influence woodland structure and to exploit such abiotic influences to improve our ability to model woodland structure from digital aerial photography. We developed and applied a methodology for automated tree canopy cover mapping using an object-oriented classifier. The resulting classification was used to scale up stand inventory measurements (0.1 ha) across 11 mountain ranges to a 3,250 km2 area. Predictive models were compared with field-measured values from a validation sample for tree canopy cover, basal area, height, and stand density index. Linear mixed-effects regression models demonstrated consistent relationships between woodland structure attributes and environmental variables. More productive sites supported greater tree densities, whereas less productive sites supported fewer, larger trees. Relatively weak relationships for certain variables (e.g., tree height) suggest that woodland structure-environment relationships are partially obscured by natural disturbances and land use history.

Influence of fire frequency on &lt;i&gt;Colophospermum mopane&lt;/i&gt; and &lt;i&gt;Combretum apiculatum&lt;/i&gt; woodland structure and composition in northern Gonarezhou National Park, Zimbabwe

We investigated the long-term effects of fire frequency on Colophospermum mopane and Combretum apiculatum woodland structure and composition in northern Gonarezhou National Park (GNP), Zimbabwe. Fire frequency was categorised as high (every 1–2 years), medium (every 3–4 years) and low (every 5–6 years). The following variables were measured or recorded: plant height, species name, canopy depth and diameter, basal circumference, number of stems per plant, plant status (dead or alive) and number of woody plants in a plot. There was a positive correlation (r = 0.55, P = 0.0007) between annual area burnt (total from January to December) and annual rainfall (average over two rain stations per rain year, July to June) between 1972 and 2005. A total of 64 woody species were recorded from C. mopane and C. apiculatum woodlands. Mean plant height increased from 4.5 to 8.2 meters in C. mopane woodland and from 4.5 to 5.1 meters in C. apiculatum woodland in areas subjected to high and low fire frequencies. In C. mopane woodland, low fire frequency was characterised by a significantly low density of woody plants (P &lt; 0.001), however, with a significantly high mean basal area (P &lt; 0.001). Fire frequency had no significant effect on species diversity (P &gt; 0.05). Our results suggest that C. mopane and C. apiculatum woodlands are in a state of structural transformation. Fire frequency effects, however, appear to be woodland specific. Fire management strategies in GNP should take into consideration annual rainfall and the different vegetation types.Conservation implication: This study provides valuable information on fire frequency effects on woody vegetation in northern GNP, which can be used in fire management programmes for the park. The positive relationship between annual rainfall and annual area burnt emphasises the need for wildlife managers to consider annual rainfall in fire management.

Scenario analysis of alternative vegetation management options on the greenhouse gas budget of two grazing businesses in north-eastern Australia

The emerging carbon economy will have a major impact on grazing businesses because of significant livestock methane and land-use change emissions. Livestock methane emissions alone account for ~11% of Australia’s reported greenhouse gas emissions. Grazing businesses need to develop an understanding of their greenhouse gas impact and be able to assess the impact of alternative management options. This paper attempts to generate a greenhouse gas budget for two scenarios using a spread sheet model. The first scenario was based on one land-type ‘20-year-old brigalow regrowth’ in the brigalow bioregion of southern-central Queensland. The 50 year analysis demonstrated the substantially different greenhouse gas outcomes and livestock carrying capacity for three alternative regrowth management options: retain regrowth (sequester 71.5 t carbon dioxide equivalents per hectare, CO2-e/ha), clear all regrowth (emit 42.8 t CO2-e/ha) and clear regrowth strips (emit 5.8 t CO2-e/ha). The second scenario was based on a ‘remnant eucalypt savanna-woodland’ land type in the Einasleigh Uplands bioregion of north Queensland. The four alternative vegetation management options were: retain current woodland structure (emit 7.4 t CO2-e/ha), allow woodland to thicken increasing tree basal area (sequester 20.7 t CO2-e/ha), thin trees less than 10 cm diameter (emit 8.9 t CO2-e/ha), and thin trees &lt;20 cm diameter (emit 12.4 t CO2-e/ha). Significant assumptions were required to complete the budgets due to gaps in current knowledge on the response of woody vegetation, soil carbon and non-CO2 soil emissions to management options and land-type at the property scale. The analyses indicate that there is scope for grazing businesses to choose alternative management options to influence their greenhouse gas budget. However, a key assumption is that accumulation of carbon or avoidance of emissions somewhere on a grazing business (e.g. in woody vegetation or soil) will be recognised as an offset for emissions elsewhere in the business (e.g. livestock methane). This issue will be a challenge for livestock industries and policy makers to work through in the coming years.

Die Bauten der Waldarbeiter in Nordungarn

Forest labourers’ buildings in Northern Hungary . The forest has always been important in the lives of those living in Northern Hungary. Apart from the foodstuffs, the fuel and the building materials it provided, the forest was also a source of work for the poorer sections of society. The woodcutters, woodcarvers, limeburners and charcoal burners spent their nights in temporary or semi-permanent huts. This study outlines the various forms such woodland structures took. The most simple type was a half-sided and barrel-roofed hut designed to provide protection against the wind and the rain. Apart from the closed winter huts the most characteristic types are the round and rectangular huts with an open hearth in the middle used by woodcutters and limeburners. In these the men were able to sleep under the protected sides of the structure surrounding the fire.

Fire and the demography of camelthorn (Acacia erioloba Meyer) in the southern Kalahari – evidence for a bonfire effect?

AbstractFires in arid environments are rare, so are not deemed as important as in mesic savannas. We investigated mortality and resprouting amongst camelthorn (Acacia erioloba) after two fires (at Vaalbos National Park and Susanna farm) in semi‐arid savanna near Kimberley, South Africa. Resprouting response 18 months after a fire was the greatest amongst &lt;6.5 m high trees; extent of foliage damage by fire and bark thickness were the next best predictors of resprouting vigour amongst that size class. The largest size class (8–12 m height) of A. erioloba suffered the greatest mortality rates (40% and 83% at Vaalbos and Susanna respectively), with damage either severe or minor. We hypothesize that large tree mortality rates are partly attributable to well‐developed assemblages of flammable subcanopy plants producing a bonfire beneath trees. These mortality rates indicate that fire reduces both tree abundance and relative representation of large trees, and although able to resprout, A. erioloba is fire‐sensitive, which may explain its restriction to Kalahari sands where rainfall is less than 900 mm year−1. Therefore, although relatively infrequent, fires shape Kalahari woodland structure, particularly as A. erioloba is long lived and slow growing. Large trees have been shown to be important to biodiversity in the southern Kalahari, so frequent fires could impact biodiversity.

Overstorey tree density and understorey regrowth effects on plant composition, stand structure and floristic richness in grazed temperate woodlands in eastern Australia

As natural woodlands decline in both extent and quality worldwide, there is an increasing recognition of the biodiversity conservation value of production landscapes. In low-input, low-productivity grazing systems in Australia, the modification of natural woodlands through overstorey tree and woody regrowth removal are vegetation management options used by landholders to increase native grass production for livestock grazing; however, there is little empirical evidence to indicate at what tree densities biodiversity attributes are compromised. We examined the effects of overstorey tree density and understorey regowth on the floristic composition, stand structure and species richness of eucalypt woodlands in a grazing landscape in the Traprock region of southern Queensland, Australia. We sampled 47 sites stratified according to vegetation type ( Eucalyptus crebra/Eucalyptus dealbata woodland; Eucalyptus melliodora/Eucalyptus microcarpa grassy woodland), density of mature trees (<6 trees/ha; 6–20 trees/ha; >20 trees/ha), and presence/absence of regrowth. Distinct patterns in composition were detected using indicator species analysis and non-metric multidimensional scaling, with low density areas compositionally indistinguishable, although distinct from other land management units. Within vegetation type, medium tree density woodlands were compositionally similar to high density and reference woodlands. Species richness ranged from 18 to 67 species per 500 m 2 across all sites. No differences in total or native species richness were detected across management units; however, some differences in exotic species richness were detected. Differences in grass cover existed between low and high density management units, yet no difference in grass cover was evident between low and medium density management units. Our results suggest that medium tree densities may provide biodiversity benefits concordant with more natural areas, yet not adversely impact on pasture production. Retaining trees in grazing landscapes provides significant landscape heterogeneity and important refuges for species that may be largely excluded from open grassland habitats. Maintaining a medium density of overstorey trees in grazed paddocks can provide both production and biodiversity benefits.

Roost selection by non-breeding Leisler's bats (Nyctalus leisleri) in montane woodlands: implications for habitat management

We investigated roost selection by Leisler's bat (Nyctalus leisleri) before and after hibernation in 2005 in a mountain area of southern Switzerland. The study area is dominated by deciduous trees and characterised by the presence of previously managed chestnut (Castanea sativa) orchards that are now partly abandoned. In March–May and August–October, 15 radio-tracked bats (seven males and eight females) used 28 roost trees. We analysed roosts used by N. leisleri at three different levels: (i) micro-scale: features of roost cavities; (ii) meso-scale: characteristics of selected roost trees and (iii) macro-scale: structure of woodland surrounding roost trees. Selection at meso and macro-scales was obtained comparing characteristics of roost trees and surrounding woodland with potentially available trees and woodlands. Bats roosted mainly in live chestnut trees, with large diameter and absence of vegetation near the entrance. Roost trees were located closer to streams, in woodlands with a higher percentage of sweet chestnut trees and a lower tree density than random trees. Multifunctional forest management in abandoned chestnut stands, comprising recreation (chestnut harvesting) and preservation of a semi-natural habitat and its related biodiversity, would recreate the traditional woodland features – in particular an open forest structure with low tree density and presence of ancient chestnut trees – and provide suitable roosting sites to migratory N. leisleri.

Reconstructing spatial tree point patterns from nearest neighbour summary statistics measured in small subwindows

Spatial tree data are required for the development of spatially explicit models and for the estimation of summary statistics such as Ripley’s K function. Such data are rare and expensive to gather. This paper presents an efficient method of synthesizing spatial tree point patterns from nearest neighbour summary statistics (NNSS) sampled in small circular subwindows, which uses a stochastic optimization technique based on simulated annealing and conditional simulation. This nonparametric method was tested by comparing tree point patterns, reconstructed from sample data, with the original woodland patterns of three structurally different tree populations. Analysis and validation show that complex spatial woodland structures, including long-range tree interactions, can be successfully reconstructed from NNSS despite the limited range of the subwindows and statistics. The influence of the NNSS varies depending on the woodland under study. In some cases, the sampling results can be improved by reconstruction. Furthermore, it is clearly shown that it is possible to estimate second-order characteristics such as Ripley’s K function from small circular subwindows through the reconstruction technique. The results offer new opportunities for adding value to woodland surveys by making raw data available for further work such as growth projections, visualization, and modelling.

Ecology of woodlands and forests: description, dynamics, and diversity

Taking a functional rather than an ecosystem or a utilitarian approach, Thomas and Packham provide a concise account of the structure of woodlands and forests. Using examples from around the world - from polar treelines to savannahs to tropical rain forests - the authors explain the structure of the soil and the hidden world of the roots; how the main groups of organisms which live within them interact both positively and negatively. There is particular emphasis on woodland and forest processes, especially those involving the flow and cycling of nutrients, as well as the dynamics of wooded areas, considering how and why they have changed through geological time and continue to do so. This clear, non-technical, 2007 text will be of interest to undergraduates, foresters, ecologists and land managers.

Bird community variation across Polylepis woodland fragments and matrix habitats: implications for biodiversity conservation within a high Andean landscape

The scattered and dwindling Polylepis woodlands of the high Andean global hotspot have been identified as being of particular importance to biodiversity conservation, and yet little is known of the make-up of their faunal communities, how these vary across landscapes, and how well species might tolerate matrix/edge habitats. We examined the bird communities and vegetation characteristics of Polylepis woodlands and the surrounding matrix habitats at three sites in the Cordillera Vilcanota, southern Peru (3,400–4,500 m). The vegetation structure of woodlands varied significantly across the three sites but all were dominated by two Polylepis tree species, with mossy ground cover. Matrix habitats were treeless and dominated by ground-level puna grass-steppe or boulder scree vegetation. Bird species richness and diversity, encounter rates and the number of globally-threatened and restricted-range bird species were consistently higher in the Polylepis forests, than in matrix habitat. We used canonical correspondence analysis (CCA) to identify habitat gradients across the landscape, and to classify bird species according to their association with Polylepis, the matrix or Polylepis-matrix interface. There were few matrix-restricted bird species, but around half the bird community, including fourteen threatened or restricted-range species, were Polylepis-dependant. Many of these species had very narrow niches. The Polylepis-matrix interface was dominated by species traditionally considered invasive ecological generalists. Our study illustrates the overriding importance of Polylepis interior habitats, indicating that conservation strategies for high Andean birds must focus on patch size maintenance/enlargement, enhancement of within-patch habitat quality, and efforts to safeguard connectivity of suitable habitat across what is essentially an inhospitable puna/scree matrix.

Saproxylic beetle assemblages of three managed oak woodlands in the Eastern Mediterranean

Oak woodlands belong to the natural vegetation in most Mediterranean regions but have suffered from a long history of woodland devastation and overgrazing. The remaining woodlands have been managed in different ways, and we expected this to have effects on the fauna associated with trees. We investigated three different sites in the Eastern Mediterranean with flightinterception traps to analyse the impact of woodland management on dead wood and tree structures and the relevance for saproxylic beetle assemblages. Our results show significant differences in trunk diameter, stem density and dead wood diversity between the three sites. Old oaks in semiopen woodland are characterised by diverse stages of dead wood and harboured most saproxylic species (74 species out of a total of 98) and most individuals. With regard to rarefied species richness, we found that coppice woodland with a high stem density and medium-sized trees has the most diverse beetle assemblage (19.7 species per 100 individuals). Species richness was in general strongly associated with the diameter of the oaks, but, surprisingly, was also of the same level as species numbers reported from studies in Central Europe. The large number of singletons, which made up 40 % of the entire sample, may indicate a considerable number of species that were not trapped. We discuss the impact of different management options on tree shape and woodland structure, issues which are also important for the saproxylic beetle assemblage associated with Mediterranean oaks. We conclude that oak woodlands in the Middle East – and especially those woodlands that have been used and managed in a sustainable way – represent a valuable resource for insect diversity.