Factors influencing vegetation gradients across ancient‐recent woodland borderlines in southern Sweden

Abstract. We studied gradients in field layer vegetation across ecotone‐type borderlines between 12 ancient woodlands and adjacent secondary deciduous woodlands on former arable land. The aim of the study was to determine how distance from the borderline influences species distributions as compared with soil factors and degree of canopy closure. Correspondence Analysis showed that distance from the borderline is closely related to the first ordination axis at all study sites. Canonical Correspondence Analysis with variation partitioning revealed that distance from the borderline was the single most important factor in explaining vegetation variation. In general, the results suggest the following order of decreasing importance: Distance from the borderline < Soil reaction < Soil nitrogen < Soil moisture < Canopy cover. However, the sum of soil variables, as estimated by weighted averages of Ellenberg indicator values for moisture, reaction and nitrogen, accounted for as much as ca. 50–70% of the total variation explained by environmental variables. Important gradients in field layer vegetation are due to a decrease in typical woodland species and an increase in other species with increasing distance from the ancient woodland. The results suggest dispersal limitation of woodland species as an important determinant of secondary forest succession. However, the importance of distance to species distributions decreases with increasing stand age as most woodland species gradually colonize the recent woodlands. After 70 yr, ca. 50 % of the woodland species present at a site showed complete colonization within 50 m from the ancient woodland border.     

Relations between the floristic composition of isolated young woods and their proximity to ancient woodland

Abstract. Recent studies indicate that, in the present-day agricultural landscape, the floristic composition of young woodland communities can be fully developed if the woods are situated adjacent to ancient woodlands. Four 70-yr-old deciduous woods in the Carpathian foothills were examined in relation to three adjacent ancient oak-hornbeam and oak-pine woodlands, which are the nearest source of woodland species diaspores. On the basis of data from 208 plots, the frequencies of various species groups in the field layer of the woods were analysed. The dependence of vegetation differentiation within the recent woods on (a) distance to the border with the ancient woodlands and (b) light intensity was examined by Partial Detrended Canonical Correspondence Analysis (DCCA). A significant relation between distance to ancient woodland and species composition was found for recent woods on rich brown soils. The vegetatively propagating species, myrmecochores and small autochores attained higher cover values near ancient woodland; endozoochores and anemochores were most abundant further away. Within recent, more open woods on poor podzolic and leached brown soils, colonisation is strongly inhibited by dense growth of Carex brizoides; here, vegetation regeneration is much slower than in woods on rich soils much further away from the source of diaspores.     

The ground beetle fauna of ancient and recent woodlands in the lowlands of north-west Germany (Coleoptera, Carabidae)

In north-west Germany the ground beetle fauna was investigated using pitfall traps at 79 sampling sites in ancient woodlands and recent woodlands (with and without direct contact to old stands). Two woodland types were considered: The Quercion robori-petraea-woodlands (oak-beech-type) on mainly sandy soils and the Stellario-Carpinetum-woodlands (hornbeam-type) on mainly loamy soils. The number of recorded ground beetle species inhabiting exclusively or predominantly woodlands in the investigation area is significantly higher in ancient stands of both woodland types than in recent ones. No statistically substantiated relation between habitat size (both about 1800 and in 1990) and the number of characteristic woodland ground beetle species could be ascertained. Carabus glabratus and Abax parallelus show a distinct focus in ancient woodlands. Significantly more records of Carabus violaceus and Abax parallelepipedus are known from ancient woodlands than from recent ones. Twelve of the 16 ground beetle species, for which no difference in the colonisation of ancient and recent woodlands was ascertained, are macropterous. Half of the eight brachypterous woodland species is exclusively or predominantly found in ancient woodlands, suggesting that power of dispersal is an important factor which determines the species number in woodland fragments of different age.     

Ecology and dynamics of the woody vegetation on the Kalahari Sands in Hwange National Park,Zimbabwe

The woody vegetation on Kalahari sand deposits in Hwange (ex-Wankie) National Park, Zimbabwe was classified into nine types on the basis of species composition. Ordination of the data showed that the types which occupy the ends of the major (soil-type) gradient are easily distinguishable, viz. well developed, mature Baikiaea plurijuga woodlands on deep sands, and scrub Terminalia sericea and mixed woodland on soils with a higher clay content or compact layer. The central groups of stands, involving mixed woodlands and scrub, were less easy to interpret, and previous logging disturbance is involved.In the disturbed Baikiaea woodlands recruitment appears to be less than is required for long-term maintenance, even given that some of the measurements may have led to underestimates. Elephants were shown to have only a minor effect, and are relatively insignificant as agents of change in the woodlands. Depth of sand and soil moisture regime are the predominant factors determining overall vegetation structure. Fire is a dominant feature in scrub areas and interacts with frost, which has a periodic severe effect on developing saplings in scrub and in some disturbed woodlands. Although the relief is very flat there is a marked frost gradient from ridge areas with mature woodland into the slightly lower-lying scrub areas. A conceptual model of the dynamics of the vegetation, based on the above features, is described.     

Plant species as indicators of ancient woodland in northwestern Germany

Abstract. 315 isolated semi-natural and natural stands in NW Germany were investigated floristically, 285 stands of ancient woodlands and 30 recent ones. In the study area nearly all semi-natural and natural ancient woodlands are found on mesotrophic or eutrophic sites and can be assigned to the Fagetalia. 54 selected herbaceous and five woody Fagetalia-species have been tested in their association to ancient woodlands. 21 of the 59 selected plant species show a highly significant association to ancient woodlands and seven species show a weak significance. 31 plant species are not significantly correlated with ancient woodland sites, but 25 of them have a low frequency. The result shows that investigations of the historical ecology can help to understand floristic composition of present-day woodlands. Restriction of many woodland species to ancient woodlands, especially rare species, emphasizes the importance of woodlands with a long continuous history for the preservation of endangered species. Irrespective of ecological conditions, the restriction of plant species to ancient woodlands seems to be mainly caused by their low ability to colonize recent woodlands, especially isolated stands. Differences in the association to ancient woodlands between European countries are assumed to be a function of both time and degree of isolation of woodlands, of the dispersal mode of the plant species and of the availability of suitable habitats.     

“Ghosts of the past”: flightless saproxylic weevils (Coleoptera: Curculionidae) are relict species in ancient woodlands

Historic maps show that the Central European landscape was influenced by exploitive human land-use during the middle ages and in the following centuries. A mixture of ancient woodlands, which survived the period of woodland destruction, and recent woodlands, which were established after 1800, cover about 10% of the study area in NW Germany today. Weevils (Coleoptera: Curculionidae) of the subfamily Cryptorhynchinae with the genera Acalles, Kyklioacalles, Ruteria and of the subfamily Molytinae, tribe Acicnemidini with the genus Trachodes are all flightless and possibly influenced by landscape history. The aims of this investigation are (1) to examine the spatial distribution of flightless saproxylic weevils in ancient and recent woodlands in NW Germany and (2) to test the frequency of possible relict species in relation to historical and current woodland size. Based on a field study in 29 deciduous woodlands and species records in collections and literature, six flightless saproxylic weevils were found to be associated with ancient woodlands in NW Germany. None of these were recorded in any of the 14 recent woodlands studied. The frequency of these relict species is correlated with historical, but not with current, woodland size. Distribution maps for Lower Saxony and data on the phenology of the relict species are presented. These weevils are relict species of ancient woodland, because they were unable to colonise isolated woods that were established after 1800. All of them are dependent on dead or dying wood for larval development. The results show that ancient broadleaved woodlands with long-lasting habitat continuity are of high conservation value for invertebrate species such as saproxylic weevils.     

Lowland woodland structure and pattern and the distribution of arboreal,phytophagous arthropods

We investigated factors that limited the distribution of phytophagous species within a woodiand system in Midlothian, Scotland. A pattern analysis was conducted of phytophagous species on a total of 45 Fagus sylvatica within 15 woodlands. Species richness counted on collected leaves was tested against within-and between-wood variables. Variables used in a regression with arthropod data from Fagus were used to estimate the phytophage richness on Betula pendula and Quercus robur in the same woods. Convariance in the number of phytophages in sampled woods was found for Fagus over three years and for Fagus, Betula and Quercus in 1992. Association analysis was used to classify the woods into species rich or poor based on presence or absence matrices. The main factors that limit phytophages on Fagus (gaps along the woodland edge, depth and species richness of the field layer. density of leaf litter and the extent of contiguous woodland cover, when including hedgerows and lines of trees) affect phytophages of similar life history strategy on other tree species within the same woods. Eighty-six per cent of species were lost because certain life history stages were vulnerable to factors that prevail in woods of poor structure. The nature conservation value of woodlands could be assessed using the correlated vulnerability of particular phytophages across tree species under specific woodland conditions.     

Habitat requirements for the conservation of wood cricket (Nemobius sylvestris) (Orthoptera: Gryllidae) on the Isle of Wight, UK

In the UK, wood cricket (Nemobius sylvestris) is a ‘Species of Conservation Concern’, being restricted to only three areas in southern England. Little information is available on the specific habitat requirements of this species. In 2006, a field investigation within three woodlands on the Isle of Wight was undertaken to identify its habitat preferences. Factors positively influencing wood cricket presence within woodlands included the presence of a well-developed leaf litter layer, relatively low ground vegetation cover and height, low canopy cover and relatively short distances between individual populations. Regression models identified the degree of isolation and variables describing vegetation structure as the main predictors for wood cricket presence within woodland fragments. The results of this study indicate the preference of wood cricket for open wooded edges. Conservation efforts for this species should focus on continuation of regular management activities aimed at providing permanent open edge habitat within woodlands, to maintain viable populations.     

The persistence of calcareous grassland species in the soil seed bank under developing and established scrub

The relationships between the composition of the soil seed bank, the field layer vegetation, and the scrub canopy were investigated along a 69 m transect, grading from incipient woodland, through scrub, into intensively rabbit-grazed calcareous grassland. The results are used to assess the persistence of species associated with open calcareous grassland in the seed bank under developing scrub. Scrub age, composition and density, changed along the transect from the woodland to open grassland. A total of 35 forb and grass species were found in the field layer. The pattern evident in the scrub layer was also reflected in the herbaceous vegetation. The field layer in the most closed portion of the transect, where the scrub was oldest, was dominated by shade-tolerant species normally associated with woodland habitats. The abundance of these species decreased along the transect as the scrub age declined, and the field layer became increasingly dominated by species typical of open grassland. A total of 47 species germinated from the seed bank. Few species were recorded in the seed bank along the entire length of the transect. Overall, the seed bank was dominated by Hypericum perforatum and Centaurium erythraea, which accounted for 38.2% and 28.6% of emerging seedlings respectively. As with a number of similar studies, the composition of the seed bank had a low correspondence with the composition of the field layer vegetation. The results also emphasise that the composition of the seed bank can be viewed as an ecological palimpsest, with germinable seed of species from each stage of the old-field succession occurring in the soil. The seed bank is an important component in the re-vegetation of an area after disturbance such as scrub removal. This study supports the findings of previous research in showing that relatively few characteristic calcareous grassland species form persistent seed banks. The soil seed bank would therefore appear to be of limited value in the restoration of such grassland following scrub removal.     

Woodland restoration on agricultural land: long‐term impacts on soil quality

Woodland restoration is underway globally to counter the negative soil quality and ecological impacts of agricultural expansion and woodland fragmentation, and restore or enhance biodiversity, ecosystem functions and services. However, we lack information about the long‐term effects of woodland restoration on agricultural soils, particularly at temporal scales meaningful to woodland and soil development. This study utilized soil and earthworm sampling across a chronosequence of sites transitioning from “agricultural land” to “secondary woodland” (50–110 years) and “ancient woodland” (>400 years), with the goal of quantifying the effects of woodland restoration on agricultural land, on key soil quality parameters (soil bulk density, pH, carbon and nitrogen stocks, and earthworm abundance, biomass, species richness and diversity). Broad‐leaved woodland restoration led to significantly greater soil organic carbon (SOC) stocks compared to arable land, and young (50–60 years) secondary woodland increased earthworm species and functional diversity compared to both arable and pasture agricultural land. SOC stocks in secondary broad‐leaved woodlands (50–110 years) were comparable to those found in long‐term ancient woodlands (>400 years). Our findings show that broad‐leaved woodland restoration of agricultural land can lead to meaningful soil ecological improvement and gains in SOC within 50–110 years, and provide intel on how restoration activities may be best targeted to maximize soil quality and functions.     

Ghyll Woodlands of the Weald: Characterisation and Conservation

Ghylls are linear valley features cut into the sandy beds of the Weald of south-eastern England. The ghyll's indigenous woodlands are highly species rich at the small scale, support distinctive assemblages of cryptogamic plants, and are unique to south-east England. Field surveys were carried out for 48 ghyll woodlands in the Weald with a GIS used to examine the ecology, landform and conservation status of the ghyll woodlands. The data were analysed using spatial and multi-variate techniques in order to identify sub-groups or ghyll woodland communities based upon species composition, topography and geology. The ghylls are shown to be reasonably uniform for canopy vegetation type and structure and for their geological and soil characteristics. However, analysis shows that geomorphology, understorey and field layer variability may act as stronger indicators of site conditions and character. Further analysis focused on the level and extent of nature conservation protection that these unique and ancient systems receive. The study concludes that despite their ecological importance and potentially international significance, ghyll woodlands are poorly understood and protected.     

Has Botanical Enhancement of Broad‐Leaved Plantations in Milton Keynes,United Kingdom,Resulted in More Woodland‐Like Insect Assemblages?

Two methods of invertebrate sampling were used to determine how the deliberate introduction of field layer vegetation to broad‐leaved plantations influenced the associated insect assemblages. Enclosed pitfall traps and tent‐like emergence traps were employed at (1) 25‐year‐old plantations where botanical enhancement had taken place a decade previously; (2) “nonenhanced” plantations of a similar age; and (3) local ancient woods, all in Milton Keynes, Buckinghamshire, United Kingdom. The aim was to discover whether enhancement had produced a community intermediate to nonenhanced plantations and naturally established woodland. Enhancement had not successfully created plantations botanically more woodland‐like and plantation types were not constant; however, plant species richness had increased. This was also true of the insect assemblages (Coleoptera, Diptera and Hemiptera), which showed more variation in composition, though woodland communities could still be distinguished. However, those insect species present in the naturally established woods did have a significantly greater frequency and abundance in the enhanced plantations compared to the nonenhanced plantations, especially so with “woodland edge” species. Mantel tests showed significant correlations between the plant species present and insect assemblages taken by both sampling types. Although insect species richness was not significantly higher in the enhanced plantations, this correlated strongly with plant species richness and a measure of vegetation volume. The overall findings suggest that the enhancement had created plantations only subtly more like the local woodlands, though the insect assemblages had responded. However, relative to the time scale of woodland development, it is still early days.     

Floristic composition and floral phenology of the Mediterranean batha of Ariel,Samaria

Field observations over a three-year period were used to document the floristic composition, flowering and fruiting sequences of the Sarcopoterium spinosa Mediterranean batha of Ariel. This plant community was found to be species-rich, with high percentages of annuals, bushes and geophytes, low percentages of herbaceous plants, climbers and trees, and ten species considered rare in Israel. Typical Mediterranean characteristics were observed in the S. spinosa batha: spring flowering reaching a peak in April, small between-year variation in flowering and fruiting, most species having Mediterranean distribution, and partial resistance to fire.     

Seven-Year Survival of Perennial Herbaceous Transplants in Temperate Woodland Restoration

Little is known about restoring the perennial herbaceous understory of Midwestern deciduous woodlands, despite the significant and widespread degradation of remnants due to human activities. Because many woodland understory species have reproductive characters that make reestablishment from seed slow or difficult, we investigated transplanting as a strategy for introducing 24 species to a degraded early-successional woodland in central Iowa, U.S.A. Plants were planted in single-species groups of generally four individuals, and then monitored for survival five times over a 7-year period, and for flowering during the first year. After 7 years, persistence of these groups was 57% averaged across species. Survival in years 5–7 does not reflect individuals that spread beyond the original planting units by self-sowing or vegetative spread and is therefore a minimum estimate of the abundance of many species at the site. Mean percent flowering was 72% across single-species groups for 15 species monitored. We consider these survival and flowering rates acceptable indicators of establishment success, especially given drought conditions at our site in the first few years and lack of weed control beyond the first year, and evidence that transplanted species were establishing outside the original planting locations. Additional work is needed to investigate regional differences in transplant success, and methods for sustainable production of species are not suitable for introduction by seed. We caution that our results do not necessarily apply to the restoration of rare species.     

Species richness of small woodlands on the western Carpathian foothills

Sixty-six small woodland islands (0.008–2.16 ha) isolated in the agricultural landscape of the Wierzbanówka valley (western Carpathian foothills) were investigated. Analysis of historical cartographic material showed that 60 woodland islands are most probably the remnants of ancient woodlands. Among them both woodlands associated with more than one type of soil, and those with homogeneous soil conditions, were identified; the latter were divided into two groups differing in the period of isolation and anthropogenic pressure. These three groups of woodlands were analysed statistically using 12 independent variables (area, shape, distance to the nearest large woodland, mean distance to the five nearest woodland islands, cover of tree-and shrub layer, and others) and 20 dependent variables (number of all species, number of species of different growth forms, mode of dispersal, and phytosociological characters). The number of species was found to be related to habitat diversity, area, shape, isolation, and cover of tree and shrub layers. Compared with the more recently isolated and less disturbed woodlands, those isolated for longer periods and more anthropogenically disturbed were found to have fewer species, including fewer harbaceous species, woodland species, species of the Querco-Fagetea class, and also tree and shrub dyszoochores, as well as herbaceous endozoochores and myrmecochores. On the other hand, significantly more non-woodland species, species of the Molinio-Arrhenatheretea class, and tree anemochores were present here.     

Pollen analysis and planted ancient woodland restoration strategies: a case study from the Wentwood, southeast Wales, UK

This paper considers the contribution of pollen analysis to conservation strategies aimed at restoring planted ancient woodland. Pollen and charcoal data are presented from organic deposits located adjacent to the Wentwood, a large planted ancient woodland in southeast Wales. Knowledge of the ecosystems preceding conifer planting can assist in restoring ancient woodlands by placing fragmented surviving ancient woodland habitats in a broader ecological, historical and cultural context. These habitats derive largely from secondary woodland that regenerated in the 3rd–5th centuries a.d. following large-scale clearance of Quercus-Corylus woodland during the Romano-British period. Woodland regeneration favoured Fraxinus and Betula. Wood pasture and common land dominated the Wentwood during the medieval period until the enclosures of the 17th century. Surviving ancient woodland habitats contain an important Fagus component that probably reflects an earlier phase of planting preceding conifer planting in the 1880s. It is recommended that restoration measures should not aim to recreate static landscapes or woodland that existed under natural conditions. Very few habitats within the Wentwood can be considered wholly natural because of the long history of human impact. In these circumstances, restoration should focus on restoring those elements of the cultural landscape that are of most benefit to a range of flora and fauna, whilst taking into account factors that present significant issues for future conservation management, such as the adverse effects from projected climate change.     

Ecological change in British broadleaved woodland since 1947

Over the last 60 years Britain's broadleaved woodlands have undergone a complex pattern of ecological change. The total extent has expanded from c . 676 000 ha in 1947 to c . 904 000 ha in 2002, but there has also been significant turnover, with losses of ancient woodland and a gain from new planting. Structural change has occurred due, in part, to change in management. In 1947 21% of the broadleaved resource was classed as coppice, 28% as scrub and only 51% of the area as high forest, compared with 97% high forest in 2002. This has been accompanied by changes in ground flora and the regeneration pattern of tree species, which will impact upon the character of the woodlands. Woods have also become more ecologically isolated because of the decline in semi-natural vegetation in the surrounding countryside, although the long-term impacts of this are poorly understood. Other factors driving ecological change are increased pollution, change in grazing pressures, climate change, alien species and game management. Overall woodland specialist species and those of open habitats tend to be doing less well than woodland generalists. Progress has been made in reversing some adverse impacts such as acid deposition, and action is being taken to reduce the impact of others such as over-grazing by deer. However, some drivers, notably climate change, will be more difficult to address. In the long term integrated management of woods as landscape components whilst meeting economic and societal needs will be required.     

Vegetation history of the SE section of the Zagros Mountains during the last five millennia; a pollen record from the Maharlou Lake, Fars Province, Iran

A pollen diagram was derived from a 150 cm core taken from the shallow hypersaline Lake Maharlou in the south-eastern part of the Zagros Mountains, SW Iran. The pollen record shows that Quercus brantii woodland and Pistacia–Amygdalus scrub dominated the area during the late Holocene. The record starts at around 5700 cal b.p. with a dry period during which both Pistacia–Amygdalus scrub and Quercus brantii woodland were at their minimum extent. This period was followed by the expansion of Pistacia–Amygdalus scrub in the area and the spread of Quercus brantii woodlands at higher altitudes. An important occupation phase, characterized by the appearance of several cultivated tree species such as Juglans, Olea, Vitis and Platanus, started at ca. 4300 cal b.p., coinciding with the onset of the Bronze Age civilization of Jiroft in Central Iran. Human activities become very clear after 3700 cal b.p. Around 2700 cal b.p., extensive stands of Pistacia–Amygdalus scrub became profoundly degraded, presumably under strong human pressure coinciding with the beginning of the Persian Empires. The maximum expansion of the Quercus brantii woodland occurred about 2100 to 1700 cal b.p. This woodland remained relatively stable until the end of the diagram at 400 cal b.p.     

Effect of proximity to ancient deciduous woodland on restoration of the field layer vegetation in a pine plantation

The influence of dominant tree species. soil conditions and distance ärom an adjacent ancient ouk-liernbeam woodland upon the floristic composition. species richness and spatial distributions of species in a pine wood planted on dry rendzina soil were studied in southern Poland. It was found that. in spite of a 52-yr long succession. the cover and composition of species in the pine wood were significantly different from that in the adjacent ancient woodland. Canonical correspondence analysis (CCA) and stepwise regression analyses showed that the distance to the ancient woodland had a significant influence on species distributions in the recent wood. The numbers of species from the Querco-Fagerea class. vegetatively reproducing species and myrrnochores decreased with this distance. whereas the numbers of tree species in the shrub and field layers and anemochores increased. The light intensity had a positive effect on the numbers of species in the shrub layer. non-woodland species and anemochores. The number of woodland species increased considerably with the cover of quickly decomposing litter and with thickness of the humus layer. The migration rate of many woodland species. calculated on occurrence of the farthest individuals was very' slow. varying from 0J8 m yr' to 0.38 m yr'. These results indicate that the availability of micro-sites suitable for seed germination and plant development determined the successful colonization of the recent wood to an extent comparable with the seed dispersal.