Current Landscapes Research Articles

Untangling ‘integration’ in urban development policy debates

Urban integration is seemingly on the lips of all involved with urban development in South Africa. One can be forgiven for thinking it is the magic bullet that will resolve the many intractable problems that mark South Africa’s cities. Urban integration is the core idea that underpins the unfolding Urban Renewal Strategy of the government. The notion emerges strongly in the recently published Draft White Paper on Urbanisation. It is also at the heart of the Urban Development Framework (UDF) that was launched in 1997 as the government’s policy approach to urban development and reconstruction. Urban integration is indeed ubiquitous in the current policy landscapes of South Africa. Yet, its meaning and its application remains shrouded in confusion, with a tendency for hubris.

Natural disturbance and old-forest management in the Alberta Foothills

There is no widely accepted definition of old growth for west central Alberta. The Foothills Model Forest used tree species composition and time since major disturbance to more broadly define old forest and a stochastic model to project levels of old forest across a landscape. Historically, the simulated "natural" forest landscape was, at any one time, mostly covered by young forest due to active fires. Areas of mature and old forest were, and likely always have been, in the minority. There were even rare times historically when virtually no old forest existed over vast landscapes, and what little did persist occurred in small, isolated patches. The single greatest human influence on old growth in the Alberta Foothills appears to have been successful fire control, which has produced forests today that are on average older than would be expected under natural conditions. Managers of both protected areas and working forests are implementing or developing strategies to restore forests to more natural conditions, and at the same time managing old forest to ensure that it remains a part of current and future forest landscapes. We describe an old-forest analysis and strategy recently incorporated into a new Forest Management Plan for the Weldwood of Canada Limited Forest Management Area. Traditional attitudes toward old forest and its role in highly dynamic landscapes are being revisited on the path to a consistent and broadly supported old-forest strategy. Key words: old growth, management, natural disturbance, Alberta

Análise da paisagem como premissa para a elaboração de plano diretor

After january 8, 1993, with arrival of the Landscape law in France, politicians became to consider landscape to conceive theirs urban planning documents. In this context, Vaulnaveys-Le-Haut, near Grenoble, revised its master plan. The city landscape was changing in peri-urbans zones with effects of cultivated lands abandon and arrival of new habitants. A specific landscape study was done; it was based on a sensitive and concrete analysis of current and future landscapes. This work enumerates landscape goals that were translated in a reference chart to politicians. The master plan has effective instruments to enforce landscape protection. So, from landscape project a proposition of zoning considering only landscape criteria was done to Vaulnaveys-Le-Haut.

Forest Landscape Response to Different Harvest Scenarios under Climate Warming – A Spatial Simulation Study

This study examined forest landscape responses to climate warming in a large (~0.5 million ha) boreal and northern hardwood forest region in northern Wisconsin, U.S.A. We examined whether it contributed to the decline of currently predominant tree species and whether harvests can be used as effective means to prolong the transformation of current forest landscapes to those under warmer conditions. We used a modeling approach by linking a spatially explicit landscape model (LANDIS) with a gap model (LINKAGES). Individual tree species responses at stand scales were simulated with LINKAGES, which integrated soil, climate and species data. Such responses were quantified as inputs for LANDIS, which was then used to integrate large spatial processes such as disturbance and harvesting with ecosystem processes. This protocol allowed us to examine regional forest landscape response to climate warming at the species level with greater realism than by using gap models or landscape transition models alone. Our simulation results suggest that forest landscapes in two ecoregions of northern Wisconsin would experience a significant change under a climate-warming scenario that a 5°C temperature increase occurs over next 100 years. In the lakeshore ecoregion, with more favorable water and nutrient conditions, currently dominant boreal and northern hardwood forests would transform into southern hardwood forests. This result is consistent with the general trends simulated by other models for this region, but shows that landscape transition takes much longer time. By incorporating realistic initial seed source and simulating spatially explicit seed dispersal, our results suggest that the landscape transition is gradual and becomes apparent during 2150–2300 in contemporary time assuming warming occurs from the beginning of this century. Forest harvesting plays an important role in delaying the decline of boreal forests and northern hardwoods. The greatest differences in resulting landscapes under different harvest scenarios (clear cutting group selection, and selection cutting) occurred starting around year 2150. However, harvest does not alter the long-term impacts of climate warming, as the proportions of various cover types simulated under different harvest scenarios at year 300 are very similar. At year 2300 in the lakeshore ecoregion, formerly dominant paper birch, yellow birch, sugar maple, balsam fir, and quaking aspen forests were replaced largely by southern oak species (bur oak, white oak, and black oak), white ash, and hickory. Boreal forests in this ecoregion completely disappeared, while northern hardwoods became a minor cover type compared to southern hardwood forests. A more dramatic transformation occurred in the barrens ecoregion. More than 98% of jack pine and red pine forests disappeared. Because southern hardwood species may be unable to reproduce and establish under warming conditions, the barrens ecoregion could transform into an area with only grass and shrub species.

Conformational transition states of a beta-hairpin peptide between the ordered and disordered conformations in explicit water.

The conformational transition states of a beta-hairpin peptide in explicit water were identified from the free energy landscapes obtained from the multicanonical ensemble, using an enhanced conformational sampling calculation. The beta-hairpin conformations were significant at 300 K in the landscape, and the typical nuclear Overhauser effect signals were reproduced, consistent with the previously reported experiment. In contrast, the disordered conformations were predominant at higher temperatures. Among the stable conformations at 300 K, there were several free energy barriers, which were not visible in the landscapes formed with the conventional parameters. We identified the transition states around the saddle points along the putative folding and unfolding paths between the beta-hairpin and the disordered conformations in the landscape. The characteristic features of these transition states are the predominant hydrophobic contacts and the several hydrogen bonds among the side-chains, as well as some of the backbone hydrogen bonds. The unfolding simulations at high temperatures, 400 K and 500 K, and their principal component analyses also provided estimates for the transition state conformations, which agreed well with those at 400 K and 500 K deduced from the current free energy landscapes at 400 K and 500 K, respectively. However, the transition states at high temperatures were much more widely distributed on the landscape than those at 300 K, and their conformations were different.

Influence of herbaceous elements on butterfly diversity in hedgerow agricultural landscapes

Landscape factors influencing butterfly diversity in five agricultural landscapes with hedgerows were investigated in western France. Two main questions were addressed: (i) how important are linear (hedge bank, road and lane verge) versus non-linear (grassland) herbaceous elements for butterfly diversity? (ii) Do number and spatial arrangement of these elements influence butterfly diversity? The contribution of each type of herbaceous elements to butterfly diversity was investigated by analyzing diversity at different levels: element, element type (road verge, hedge bank, grassland) and landscape. The spatial arrangement of herbaceous elements was measured by two indices: (i) the mean distance between each grassland and its nearest neighbor (ii) the grain size of the landscape (mean field size). Linear herbaceous elements provided higher butterfly diversity than grasslands. Moreover, butterfly diversity was positively correlated to the surface area in linear herbaceous elements. As they are the remaining low input and lightly managed herbaceous elements in current agricultural landscapes, they contribute greatly to the maintenance of butterfly diversity. Grain size of the landscape was not correlated to butterfly diversity, however, mean distance between nearest grasslands was strongly positively correlated to butterfly diversity. These results show that species movement in the five landscapes was neither prevented by the field size of the studied landscapes nor by the distance between grasslands. The advantages of the landscape heterogeneity measures used in this study and of the method of diversity partitioning, for biodiversity studies in agricultural landscapes, are discussed.

Closing the gaps in genetics legislation and policy: a report by the new york state task force on life and the law.

The New York State Task Force on Life and the Law, a state bioethical policy commission, recently completed a project addressing the ethical, legal, and social concerns surrounding the predictive uses of genetic testing. Its report, Genetic Testing and Screening in the Age of Genomic Medicine, makes legislative, public policy, and practice recommendations on a host of issues. As part of this project, the Task Force reviewed the current policy and legislative landscapes related to confidentiality protections for genetic information and the use of genetic information by insurers. It also assessed requirements for informed consent to clinical genetic testing and for the use of clinical samples for genetics research. The Task Force considered gaps and unintended consequences of relevant genetic testing legislation and assessed its flexibility to address new uses of genetic testing, such as pharmacogenetic testing, and new ways of offering tests, such as multiplex testing panels. The Task Force also considered the relevance of the pleiotropic characteristic of genes for issues of informed consent to genetic testing and the confidentiality of genetic information. The Task Force's recommendations, presented here, seek to promote the appropriate uses of clinical genetic testing and research while preventing potential harms.

An Alternative Point of View

An Alternative Point of View

Nature, society and history in two contrasting landscapes in Wisconsin, USA: Interactions between lakes and humans during the twentieth century

Landscapes result from the interaction between nature and society. To understand current landscapes, it is essential to disentangle this interaction; to accomplish this, an historical approach is necessary. Here we focus on the interaction between humans and lakes during the last century in two sites in Wisconsin, USA, a state where lakes, in excess of 10,000, have played an important role in the evolution of the landscapes they belong to. We draw contrasts between the two localities, which are set in landscapes that differ in their physiographic setting, environmental history, and current structure. One, in northern Wisconsin, is a forested recreational lake district; the other, in southern Wisconsin, is dominated by agricultural uses and urban and suburban development. We contend that a common development in both localities has been the increase in the value that society attaches to lakes. As a consequence, lakes are playing a bigger role in the evolution of the terrestrial landscapes surrounding them.

Upland plant communities — sensitivity to change

The factors that influence changes in the upland plant communities of Scotland, and hence result in changes in the landscape, are examined with particular reference to the decline in the cover of heather moorland. These factors include natural disturbances, such as climate change and fire, but the influence of man-made disturbances on the landscape, notably due to sheep grazing and deforestation, has been much greater. Despite this, it is argued that plant communities differ in their fragility and some current upland landscapes are not particularly sensitive to some types of disturbances, at least under moderate herbivore loads. However, the impact of potential reductions in herbivore loads, in combination with other factors (e.g., climate change and increased atmospheric nitrogen deposition), on the rate of vegetation change cannot be predicted with confidence at present. Understanding the mechanisms underlying spatial and temporal variation in the sensitivity of upland plant communities to increasing disturbances in the future is the challenge facing both ecologists and those interested in landscape management.

Caracterización de los paisajes terrestres actuales de la península de Yucatán

El objetivo de este trabajo es presentar la caracterización de los paisajes actuales de la península de Yucatán. Para su estudio se empleó el método físico-geográfico-paisajístico, a partir de un esquema integral de componentes naturales (geomorfología, altitud, climas, suelos, uso del suelo y vegetación), derivado de mapas digitizados. Se cruzó entre si la información relativa a estos componentes mediante un sistema de información geográfica, de lo que se obtuvieron nuevas combinaciones. Para el proceso de clasificación de los paisajes se utilizó lo sugerido por Mateo (1984), con respecto a los índices diagnósticos y los diferentes niveles taxonómicos. En los mapas obtenidos de paisajes se identificaron seis clases de éstos en el estado de Quintana Roo, tres en Campeche y cuatro clases para Yucatán.

Historical forest patterns of Oregon's central Coast Range

To describe the composition and pattern of unmanaged forestland in Oregon's central Coast Range, we analyzed forest conditions from a random sample of 18 prelogging (1949 and earlier) landscapes. We also compared the amount and variability of old forest (conifer-dominated stands >53 cm dbh) in the prelogging landscapes with that in the current landscapes. Sixty-three percent of the prelogging landscape comprised old forest, approximately 21% of which also had a significant (>20% cover) hardwood component. The proportions of forest types across the 18 prelogging landscapes varied greatly for both early seral stages (cv=81–194) and hardwoods (cv=127) and moderately for old forest (cv =39). With increasing distance from streams, the amount of hardwoods and nonforest decreased, whereas the amount of seedling/sapling/pole and young conifers increased. The amount of old forest was significantly greater (p< 0.002) in prelogging forests than in current landscapes. Old-forest patterns also differed significantly (p< 0.015) between prelogging and current landscapes; patch density, coefficient of variation of patch size, edge density, and fragmentation were greater in current landscapes and mean patch size, largest patch size, and core habitat were greater in prelogging forests. Generally, old-forest landscape pattern variables showed a greater range in prelogging landscapes than in current landscapes. Management strategies designed to increase the amount of old forest and the range in landscape patterns would result in a landscape more closely resembling that found prior to intensive logging.

GHOSTS OF HABITATS PAST: CONTRIBUTION OF LANDSCAPE CHANGE TO CURRENT HABITATS USED BY SHRUBLAND BIRDS

Models of habitat associations for species often are developed with an implicit assumption that habitats are static, even though recent disturbance may have altered the landscape. We tested our hypothesis that trajectory and magnitude of habitat change influenced observed distribution and abundance of passerine birds breeding in shrubsteppe habitats of southwestern Idaho. Birds in this region live in dynamic landscapes undergoing predominantly large-scale, radical, and unidirectional habitat change because wildfires are converting shrublands into expanses of exotic annual grasslands. We used data from field surveys and satellite image analyses in a series of redundancy analyses to partition variances and to determine the relative contribution of habitat change and current landscapes. Although current habitats explained a greater proportion of total variation, changes in habitat and measures of habitat richness and texture also contributed to variation in abundance of Horned Larks (Eremophila alpestris), B...

Ghosts of Habitats past: Contribution of Landscape Change to Current Habitats Used by Shrubland Birds

Models of habitat associations for species often are developed with an implicit assumption that habitats are static, even though recent disturbance may have altered the landscape. We tested our hypothesis that trajectory and magnitude of habitat change influenced observed distribution and abundance of passerine birds breeding in shrubsteppe habitats of southwestern Idaho. Birds in this region live in dynamic landscapes undergoing predominantly large-scale, radical, and unidirectional habitat change because wildfires are converting shrublands into expanses of exotic annual grasslands. We used data from field surveys and satellite image analyses in a series of redundancy analyses to partition variances and to determine the relative contribution of habitat change and current landscapes. Although current habitats explained a greater proportion of total variation, changes in habitat and measures of habitat richness and texture also contributed to variation in abundance of Horned Larks (Eremophila alpestris), Brewer’s Sparrows (Spizella breweri), and Sage Sparrows (Amphispiza belli). Abundance of birds was insensitive to scale for nonspatial habitat variables. In contrast, spatial measures of habitat richness and texture in the landscape were significant only at large spatial scales. Abundance of Horned Larks, Western Meadowlarks (Sturnella neglecta), and Brewer’s Sparrows, but not Sage Thrashers (Oreoscoptes montanus) or Sage Sparrows, was positively correlated with changes toward stable habitats. Because dominant habitat changes were toward less stable conditions, regional declines of those birds in shrubsteppe habitats reflect current landscapes as well as the history, magnitude, and trajectory of habitat change.

Mediterranean vegetation dynamics: modelling problems and functional types

Gap models have been applied to a wide range of ecosystems, mainly temperate and boreal forests, but rarely have such models been applied to Mediterranean ecosystems. In the present review we address some problems of gap models for predicting the long-term dynamics of Mediterranean ecosystems, and we suggest plant functional types suitable for modelling based on responses to disturbance. Most gap models do not take into account different life forms, interactions with fire (e.g., resprouting and stimulation of the germination), and underground structures. Long term human impact on Mediterranean ecosystems has made a significant impact on the current landscapes. That intense land use, involving long-lived slow-growing species, has had long-term consequences. It is not possible to understand Mediterranean vegetation and to validate any model without considering these factors. The lack of data for Mediterranean species may be overcome by taking into account correlations of traits and trade-offs between different functional types. A simple disturbance-based functional group system is discussed. Abbreviations :M BD mediterranean basin; MTED mediterranean-type ecosystems.

People and the Land Through Time: Linking Ecology and History

All ecosystems have a history of past human impacts, some obvious, others subtle, Emily Russell contends in this fascinating exploration of historical ecology. To understand the lingering consequences of human history on current ecosystems and landscapes, and conversely to understand the role that changing environments have played in human history, the author urges an interdisciplinary approach. Different disciplines working together can develop information that none alone can provide. History matters for all manner of ecological and environmental studies, both theoretical and applied, says Russell, and integration of these disciplines can assist us in dealing responsibly with our role in the biosphere.

A landscape level comparison of pre-European settlement and current soil carbon content of a forested landscape in upper Michigan

A large forested landscape (18 640 ha) located in Michigan's central Upper Peninsula was examined to estimate current and pre-European mineral soil carbon (C) content. Utilizing current forest stand information and pre-European settlement forest data, a landscape level soil C estimate was made for each time period and the change in soil C over the 150-year interval was quantified. Soil, forest type, and age class information were entered into a geographical information system (GIS); high medium, and low C levels were assigned to soils based on forest type and age class groupings. Using organic matter data from soil surveys of the area, a range of mineral soil C values was determined for each soil mapping unit and vegetation combination, and a percent C value was estimated based on previously assigned C levels. Estimates of average percent C were calculated for both current and pre-European landscapes to be 9.7% and 11.7%, respectively. Overall, there appears to be a decrease in soil C content since European settlement as a result of changes in forest cover and land use. Due to the strong relationship between forest type and soil C content, an increase of urban/brush areas, and a shift from hemlock and conifer forest types to hardwoods and mixed pine/hardwood forests since European settlement, there has been a reduction of the average landscape level soil C on a g/m 2 basis. The net reduction in mineral soil C content on this landscape is estimated to be approximately 0.3 to 0.8 Tg C (in the upper 10–25 cm of mineral soil) over the 150 years since European settlement of the area.

A conceptual approach for evaluating the storage and release of contaminants derived from process based land degradation studies: an example from the Guadalentı́n basin, Southeast Spain

The implications for land use change for the storage and release of contaminants in the Guadalentı́n catchment in SE Spain are considered. As part of a large project examining the impact of land use and climate change on arid land degradation, information has been collected on how soil properties, hydrology and vegetation are evolving on abandoned land. This information was used to characterise land degradation response units in two areas, one on slates the other on marls and limestone. The way in which changes and degradation processes on the different land units influence the ability of the land units to retain contaminants, as well as the risk of these being transported by erosion, was evaluated. It was concluded that in the slate area, the only areas of risk are in the valley bottom flood plains. Chemicals may be transported here by subsurface flow from the slopes. In the limestone and marl area there is a more general risk because of the high erodibility of the soil and because abandoned areas do not revegetate quickly following abandonment. Water from these overland flow producing areas may erode agricultural fields which are situated at the lowest position in the landscape. In the marl and limestone area, a comparison was made for the situation in 1957 and 1993. The situation today is different from 1957 because of larger field sizes and changed land-use. In both the old and current landscapes, there were significant stores of sediment in the agricultural areas that form potential sediment and contaminant sources.

The importance of shelter for butterflies in open landscapes

In Britain, much emphasis has been placed on conserving butterfly species in specialized habitats, since this is where most of it‘s threatened butterflies exist, whilst the wider countryside has been largely overlooked. However, there is increasing awareness that small improvements to the dominant landscape could potentially reap huge benefits to the populations of many of Britain‘s butterfly species. Recent studies have also stressed the importance of the landscape scale in the conservation of butterflies in small fragmented habitats. In this paper, we examine data from a variety of sources and conclude that the importance of shelter in open landscapes may be underestimated since recording is often restricted to the optimum conditions suggested by the Butterfly Monitoring Scheme. In less favourable conditions, butterflies may place greater reliance on those components of the landscape offering shelter. In light of the current policy of agricultural de-intensification we discuss how modifications to our current landscapes could benefit a wide range of species.

Bird Habitat Relationships in Natural and Managed Forests in the West Cascades of Oregon

Ecologists have advocated retaining various densities of canopy trees in harvest units in Pacific Northwest forests. In contrast to clear‐cutting, this practice may better emulate the patterns of disturbance and structural complexity typical of natural forests in the region. Several ecological attributes, including vertebrate habitat diversity, are thought to be associated with stands of complex structure. The goal of this study was to determine bird abundance in canopy retention sites relative to other common stand types in the Pacific Northwest and to develop habitat functions for extrapolating bird abundance across current and future landscapes. We used data from five previous studies in the west central Cascades of Oregon to compare bird abundance and to develop habitat functions for forest birds across a wide range of natural and managed stand structures and ages. The 67 stands included clearcuts, retention sites, young closed‐canopy plantations, mature stands, and old‐growth stands. ANOVA revealed that 18 of the 23 species included in the analysis differed significantly in abundance among the stand types, with some species being primarily associated with each of the stand types. The habitat variables used to build habitat functions included tree density by size class, mean tree diameter, and variation in tree diameter. Linear, polynomial, and various nonlinear regression models were evaluated for each bird species. Significant habitat functions were generated for 17 of the 23 bird species. The analyses identified four habitat‐use guilds among the 17 bird species: open‐canopy; open‐canopy with dispersed large trees; structurally complex closed‐canopy; and structurally simple closed‐canopy guilds. This study is the first in the Pacific Northwest to compare bird abundances across natural stands, traditionally managed plantations, and stands managed under ecological forestry approaches. The results suggested that canopy tree retention benefits many, but not all, of the bird species we studied, Moreover, the nonlinear responses of bird abundance revealed thresholds in tree density at which bird abundance changed dramatically. Knowledge of these thresholds allow managers to design stands for specific biodiversity objectives. The habitat functions presented here can be used to predict bird abundance based on habitat measurements derived from field data, remotely sensed data, or output from computer models of forest dynamics.