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Aim To review and synthesize multiple lines of evidence that describe the spatial patterns of land use associated with prehistoric and early historical Native American societies in eastern North America in order to better characterize the type, spatial extent and temporal persistence of past land use. Location Temperate forests of eastern North America, and the Eastern Woodlands cultural region. Methods Ethnohistorical accounts, archaeological data, historical land surveys and palaeoecological records describing indigenous forms of silviculture and agriculture were evaluated across scales ranging from local (100 km) to regional (102 km) to produce a synthetic description of land-use characteristics. Results Indigenous land-use practices created patches of distinct ecological conditions within a heterogeneous mosaic of ecosystem types. At all scales, patch location was dynamic, and patches underwent recurrent periods of expansion, contraction and abandonment. Land-use patches varied in their extent and persistence, and are broadly categorized as silvicultural (management of undomesticated woodland taxa) or agricultural (cultivation of domesticated taxa). Silvicultural patches persisted for centuries and extended kilometres to tens of kilometres around settlements and travel corridors. The dynamics of agricultural patches varied among groups, with persistence ranging from decades to centuries and extent ranging from less than a kilometre to tens of kilometres around settlements. Beyond patch boundaries, human impacts on ecosystems become indistinguishable from other drivers of environmental heterogeneity. These characteristics of patches are evident across scales and multiple lines of evidence. Main conclusions Our findings challenge the view that prehistoric human impacts on vegetation were widespread and ubiquitous, and build on previous work showing these impacts to be more localized and heterogeneous by providing quantitative descriptions of land-use patch characteristics. Collaborative efforts that combine multiple data sources are needed to refine these descriptions and generate more precise measures of land-use pattern to further investigate the history of human impacts on the Earth system. [ABSTRACT FROM AUTHOR]

Aim The assembly of a forest flora on sites abandoned from agriculture is potentially limited by the physical and chemical suitability of soils. This paper describes the post-agricultural development of soil in deciduous forest sites to gauge its importance in limiting a second-growth forest flora. Location Northern Delaware and south-eastern Pennsylvania, USA. Methods A chronosequence of 99 second-growth forest sites was assembled in the Piedmont region. Stand age ranged from 0–20 to > 100 years since canopy closure, as determined from historical aerial photographs. Seventy-four sites are likely to have experienced cultivation before regeneration of forest. The presence of large rocks or pit-and-mound microtopography suggests that the remaining 25 sites were not cultivated, although they were probably used as pasture and/or woodlot. Soil organic content, moisture, pH, and concentrations of extractable potassium, phosphorous, calcium, magnesium and sulphur were measured in samples from each site. Coarse woody debris, size of the largest tree, canopy openness and several microtopographic features were also recorded. Results Most soil variables fell into two separate but internally correlated groups: the first group including organic matter, moisture and sulphur; the second including pH, calcium, potassium and magnesium. In formerly cultivated sites, organic matter, moisture and sulphur increased gradually through the chronosequence, approaching values recorded in uncultivated sites at 81–100 years. Calcium, potassium, magnesium and pH declined sharply between the 21–40- and 41–60-year classes – probably an indirect effect related to geographic location and selective abandonment. Phosphorous also declined with time, but the decline was not as clearly defined. Main conclusions The progress of soil recovery observed here is faster than rates implied in other studies, possibly because these sites experienced a period as pasture before reversion to forest. Sites appear to have returned to undisturbed-forest levels as fast as or faster than the predicted accumulation of a forest flora, suggesting that assembly of second-growth forest communities is not limited by the rate of soil development in this region. [ABSTRACT FROM AUTHOR]

Aims Both human and non-human determinants have shaped Mediterranean forest structure over the last few millennia. The effects of recent human activities on forest composition, however, remain poorly understood. We quantified changes in forest composition during the past century in the mixed forests of Quercus suber (cork oak) and Q. canariensis (Algerian oak), and explored the effects of forest management and environmental (climate, topography) factors on forest structure at various spatial and temporal scales. Location Mountains north of the Strait of Gibraltar (southern Spain). Methods First, we quantified 20th-century changes in species composition from a series of inventories in nine mixed forests ( c. 40,000 ha), and examined them in terms of the management practices and environmental conditions. Second, we analysed present-day Q. suber and Q. canariensis stand structure along environmental gradients at two spatial scales: (1) that of the forest landscape ( c. 284 ha), combining local inventories and topographic variables and using a digital elevation model; and (2) regional ( c. 87,600 km2), combining data from the Spanish Forest Inventory for the Andalusia region and estimates of climatic variables. Results Historical data indicate anthropogenic changes in stand composition, revealing a sharp increase in the density of cork oaks over the last century. Forest management has favoured this species (for cork production) at the expense of Q. canariensis. The impact of management is imprinted on the present-day forest structure. The abundance of both species increases with annual mean precipitation, and they coexist above 800 mm (the minimum threshold for Q. canariensis). Quercus suber dominates in most of the stands, and species segregation in the landscape is associated with the drainage network, Q. canariensis being clearly associated with moister habitats near streams. Main conclusions Our study quantitatively exemplifies a recent human-mediated shift in forest composition. As a result of forest management, the realized niche of the cork oak has been enlarged at the expense of that of Q. canariensis, providing further evidence for humans as major drivers of oak forest composition across the Mediterranean. Recent regeneration problems detected in Q. suber stands, a reduced demand for wood products, conservation policies, and climate change augur new large-scale shifts in forest composition. [ABSTRACT FROM AUTHOR]

Aim To deepen understanding of the factors that influenced the formation of oak savanna in central Kentucky, USA. Particular attention was focused on the link between historical disturbance and the formation of savanna ecosystem structure. Location Central Kentucky, USA. Methods We used dendrochronological analysis of tree-ring samples to understand the historical growth environment of remnant savanna stems. We used release detection and branch-establishment dates to evaluate changes in tree growth and the establishment of savanna physiognomy. We contrasted our growth chronology with reference chronologies for regional tree growth, climate and human population dynamics. Results Trees growing in Kentucky Inner Bluegrass Region (IBR) savanna remnants exhibited a period of suppression, extending from the establishment date of the tree to release events that occurred c. 1800. This release resulted in a tripling of the annual radial growth rate from levels typical of oaks suppressed under a forest canopy (< 1 mm year−1) to levels typical of open-grown stems (3 mm year−1). The growth releases in savanna trees coincided with low branch establishment. Over the release period, climatic conditions remained relatively constant and growth in regional forest trees was even; however, the growth increase in savanna stems was strongly correlated with a marked increase in Euro-American population density in the region. Main conclusions Our data suggest that trees growing in savanna remnants originated in the understorey of a closed canopy forest. We hypothesize that Euro-American land clearing to create pasturelands released these trees from light competition and resulted in the savanna physiognomy that is apparent in remnant stands in the IBR. Although our data suggest that savanna trees originated in a forest understorey, this system structure itself may have been a result of an unprecedented lack of Native American activity in the region due to population loss associated with pandemics brought to North America by Euro-Americans. We present a hypothetical model that links human population dynamics, land-use activities and ecosystem structure. Our model focuses on the following three land-use eras: Native American habitation/utilization; land abandonment; and Euro-American land clearance. Ecological understanding of historical dynamics in other ecosystems of eastern North America may be enhanced through recognition of these eras. [ABSTRACT FROM AUTHOR]

Aim There has been considerable debate about pre-settlement stand structures in temperate woodlands in south-eastern Australia. Traditional histories assumed massive tree losses across the region, whereas a number of recent histories propose that woodlands were originally open and trees regenerated densely after settlement. To reconcile these conflicting models, we gathered quantitative data on pre-settlement stand structures in Eucalyptus– Callitris woodlands in central New South Wales Australia, including: (1) tree density, composition, basal area and canopy cover at the time of European settlement; and (2) post-settlement changes in these attributes. Location Woodlands dominated by Eucalyptus species and Callitris glaucophylla, which originally occupied approximately 100,000 km2 in central New South Wales, Australia. Methods We recorded all evidence of pre-settlement trees, including stumps, stags and veteran trees, from 39 relatively undisturbed 1-ha stands within 16 State Forests evenly distributed across the region. Current trees were recorded in a nested 900 m2 quadrat at each site. Allometric relationships were used to estimate girth over bark at breast height, tree basal area, and crown diameter from the girth of cut stumps. A post-settlement disturbance index was developed to assess correlations between post-settlement disturbance and attributes of pre-settlement stands. Results The densities of all large trees (> 60 cm girth over bark at breast height) were significantly greater in current stands than at the time of European settlement (198 vs. 39 trees ha−1). Pre-settlement and current stands did not differ in basal area. However, the proportional representation of Eucalyptus and Callitris changed completely. At the time of settlement, stands were dominated by Eucalyptus (78% of basal area), whereas current stands are dominated by Callitris (74%). On average, Eucalyptus afforded 83% of crown cover at the time of settlement. Moreover, the estimated density, basal area and crown cover of Eucalyptus at the time of settlement were significantly negatively correlated with post-settlement disturbance, which suggests that these results underestimate pre-settlement Eucalyptus representation in the most disturbed stands. Main conclusions These results incorporate elements of traditional and recent vegetation histories. Since European settlement, State Forests have been transformed from Eucalyptus to Callitris dominance as a result of the widespread clearance of pre-settlement Eucalyptus and dense post-settlement recruitment of Callitris. Tree densities did increase greatly after European settlement, but most stands were much denser at the time of settlement than recent histories suggest. The original degree of dominance by Eucalyptus was unexpected, and has been consistently underestimated in the past. This study has greatly refined our understanding of post-settlement changes in woodland stand structures, and will strengthen the foundation for management policies that incorporate historical benchmarks of landscape vegetation changes. [ABSTRACT FROM AUTHOR]

Aim To investigate how local, regional and historical factors shape the herbaceous plant communities in fragmented riverine forests, and how the community composition and species richness of these fragments is related to the interplay between the environmental factors and specific plant life-trait combinations. Location Riverine forest fragments in the Grand-duché de Luxembourg. Methods Forest fragments were surveyed for their abundance in herbaceous plant species. All plant species where clustered into Emergent Groups (EG) by means of a formal classification based on 14 life-history traits. Within each EG, the local, regional and historical factors were related to the community composition using partial Canonical Correspondence Analyses (pCCA) and to the species richness using Generalized Linear Models (GLMs). The EG colonization ability was characterized by means of logistic regressions. Results We defined and characterized seven EGs, among which three consisted of forest specialist species (barochorous perennials, short geophytes and zoochorous perennials), which exhibited specific life-trait combinations: large and short-lived seeds and/or vernal phenology. Differences in EG composition between forest fragments were mainly explained by local environmental factors such as soil productivity and pH. The richness of barochorous perennials and short geophytes was well predicted by the historical and regional factors. The colonization ability appeared very low for barochorous perennials and short geophytes. Main conclusions Local environmental conditions appear to drive the differentiation of the riverine forest plant communities owing to the specific habitat requirements of many forest species. Spatial and temporal forest discontinuities affect the richness of forest specialist species, due to dispersal and/or recruitment limitations. The emergent group approach enhances the understanding of the relative influence of local, regional and historical factors by distinguishing between forest specialists from generalists or ‘matrix’ species, which have a masking effect. [ABSTRACT FROM AUTHOR]

Aim To enhance current attempts to understand biodiversity patterns by using an historical ecology approach to highlight the over-riding influence of land-use history in creating past, current and future patterns of biodiversity in fragmented agricultural landscapes. Methods We develop an integrative conceptual framework for understanding spatial and temporal variations in landscape patterns in fragmented agricultural landscapes by presenting five postulates (hypotheses) which highlight the important role of historical, anthropogenic disturbance regimes. We then illustrate each of these postulates with examples drawn from fragmented woodlands in agricultural areas of south-eastern Australia, and discuss these findings in an international context. Location examples are drawn from agricultural areas in south-eastern Australia. Results We conclude that there is limited potential to refine our understanding of patterns of biodiversity in human-modified landscapes based on traditional concepts of island biogeography, or simple assumptions of ongoing destruction and degradation. Instead, we propose that in agricultural landscapes that were largely cleared over a century ago: (1) present-day remnant vegetation patterns are not accidental, but are logically arrayed due to historic land-use decisions, (2) historic anthropogenic disturbances have a major influence on current ecosystem conditions and diversity patterns, and (3) the condition of remnant ecosystems is not necessarily deteriorating rapidly. Main conclusions An historical ecology approach can enhance our understanding of why different species and ecosystem states occur where they do, and can explain internal variations in ecological conditions within remnant ecosystems, too often casually attributed to the ‘mess of history’. This framework emphasizes temporal changes (both past and future) in biotic patterns and processes in fragmented agricultural landscapes. Integration of spatially and temporally explicit historical land-use information into ecological studies can prove extremely useful to test hypotheses of the effects of changes in landscape processes, and to enhance future research, restoration and conservation management activities. [ABSTRACT FROM AUTHOR]

Abstract Aim Land-use history can be an important determinant of ecosystem characteristics, even in landscapes that outwardly appear ‘natural’. In New England, like much of the eastern United States, the natural reforestation of agricultural lands over the past 150 years has created a predominantly forested landscape. Understanding the physiographical and historical factors controlling forest structure and composition is a major challenge to ecologists, conservationists and land managers. Location We studied the forest structure and composition of Petersham, Massachusetts, which is located in the Central Upland physiographical province of New England. Like much of New England, Petersham was largely cleared for agriculture by the mid-1800s, but most of the agricultural fields were abandoned and naturally reforested in the late-1800s and early 1900s. The modern landscape is > 90% forested by a mosaic of primary and secondary woodlands. Methods At seventy-four randomly selected 0.04-ha plots, we measured the abundances of all vascular plants in the overstory and understory and nine physiographical and historical variables. Results Species richness was primarily related to landform: species-rich communities occurred in poorly drained basins and species-poor communities occurred on well-drained glacial outwash. Distributions of the sixty-nine most common species were associated with (in order of importance) landform, past land use and elevation. Many species were restricted to specific physiographical conditions, but no species were restricted to specific past land uses. Nine plant associations identified by two-way indicator species analysis were associated with elevation, landform, soil texture and past land use. Ordination by canonical correspondence analysis indicated that the vegetation reflected two principal gradients: a physiographical gradient, defined by landform and soil texture, and a land-use gradient. Main conclusions These analyses... [ABSTRACT FROM AUTHOR]

Abstract Aim This study documents the vegetation history and age-structure of a rare, ridgetop dwarf pine–oak community and compares the dynamics of this unusual vegetation with similar dwarf pine communities found elsewhere in the north-eastern United States (US). Location The study area is located on the summit of Mt Everett in the Taconic Mountains of south-western Berkshire County, Massachusetts, USA (42°06′N 73°26′W). Methods Vegetation composition, tree age-structure, physical site characteristics, and evidence of fire and other disturbances were determined for twelve 15 × 15 m plots in dwarf pine–oak vegetation and two plots in oak forests on the summit. Age-structure analyses, tree-ring patterns, and historical records of human and natural disturbance were used to investigate the long-term history and dynamics of the summit vegetation. Results The summit of Mt Everett has been dominated by dwarf pines (1–3 m tall) and ericaceous shrubs similar to the modern vegetation throughout the historical period; there is no evidence that tall-stature forests occurred on the site at any point in the past few centuries. The summit supports uneven-aged stands; pitch pine (Pinus rigida ) recruitment began in the 1830s and occurred in every decade since the 1860s. Average pitch pine age is seventy-eight with a range of 12–170 years. Red oak (Quercus rubra ) and red maple (Acer rubrum ) increased in importance in the twentieth century, with most stems establishing from 1940 to 1980. Pitch pine radial growth rates averaged <0.5 mm year-1 while red oak and red maple averaged 1.0 and 0.8 mm year-1 , respectively. In some areas, hardwoods have overtopped pitch pines, apparently resulting in pitch pine mortality. Whereas most dwarf pitch pine communities occur on sites that burn frequently and have a high degree of cone serotiny, we found no evidence of recent fires or cone serotiny. Small... [ABSTRACT FROM AUTHOR]

Abstract Aim Long-term studies of landscape dynamics in relationship to changes in cultural, environmental and disturbance factors have great potential for increasing the understanding of modern ecological conditions and improving the development of conservation plans that incorporate historically important processes. In this study we compiled archaeological, historical, palaeoecological and ecological information on Martha's Vineyard to investigate temporal and spatial variation in landscape pattern and process. Although <250 km2 , this island off the Massachusetts coast embraces remarkable geographical variation and harbours uncommon plant and animal assemblages that make it a national priority for conservation. Location The study embraces the entire island of Martha's Vineyard, which lies c. 8 km south of Cape Cod and the mainland of Massachusetts. The triangular-shaped island contains three major geomorphological regions: moraine forms a series of irregular and subparallel ridges and hills 40 to over 80 m in elevation that terminate at the western end of the island in high cliffs at Gay Head and Squibnocket; sandy glacial outwash overlying moraine spreads down the northeastern end of the island forming a region of low undulating hills and shallow depressions 15–30 m in elevation, and an extensive outwash plain stretches across the central and eastern part of the island and slopes gently from 30-m elevation in the north to <3 m towards the southern coast where it is dissected by a series of north–south trending valleys that terminate in coastal ponds. In all areas except the southwest corner the island is underlain by >100 m of Quaternary and coastal plain sediments. Methods Long-term records of vegetation, fire, natural disturbance and human activity were compiled over the past 2000 years and across the physiographic variation on the island. Palaeoecological interpretations of vegetation, fire, climate and land-use history are based... [ABSTRACT FROM AUTHOR]

Presents historical and geographical approaches to address ecological questions and conservation issues with a focus on the New England landscape. Rationale behind the use of geographical and historical studies for ecological conservation; Introduction of articles published in the October 2002 issue of the 'Journal of Biogeography.'

Discusses the various aspects of environmental conservation of landscapes with a focus on the New England landscape. Challenges raised by the dynamic history for environmental conservationists and land managers; Ecological changes in the New England landscape in the past millennia; Utility of interpretation of the ecological consequences of New England.