Key concepts and research topics in landscape ecology revisited: 30 years after the Allerton Park workshop

This year marks the 30th anniversary of a momentous meeting in the history of landscape ecology—the Landscape Ecology Workshop held in Allerton Park, Illinois, USA in 1983. On this special occasion, I am inspired to make some observations and comments on the state-of-the-science of landscape ecology as a tribute to this historic event. One may argue that the workshop galvanized a shift in paradigm and the development of an “identity” for landscape ecology. The field has advanced swiftly and productively during the past three decades, and reviewing the publications in the flagship journal Landscape Ecology indicates that the Allerton Park vision has been amazingly influential in shaping the direction of the field. Based on a synoptic analysis of the literature, I discuss the core questions, key topics, and future direction of landscape ecology.     

Evolving landscapes in the headwaters area of the Yellow River (China) and their ecological implications

The relationship and feedback between landscape pattern, function and process serve to describe the behavior of a regional landscape. Based on landscape function characteristics such as biological productivity, soil nutrient content, vegetative cover, etc., a quantitative method and digital model for analyzing evolving landscape functionality in the headwaters area of the Yellow River in the People's Republic of China were devised. Through the analysis of three-phase remote sensing data from 1975, 1985 and 1995 and based upon the well-defined characteristics of this region's evolving landscape over the past 30 years, the attendant ecology of the different functional landscape ecotypes was investigated. Between 1975 and 1995 the area of AC&S (alpine cold meadow and steppe) in the source area of the Yellow River has decreased by 27.25%, ACSW (alpine cold swamp meadow) has decreased by 27.04%, ALP (alpine steppe) by 38.18% and lakes by 9.78%. The grass biomass production decreased by 752.37 Gg, of which AC&S meadows accounted for 83.8% of these losses. The overall stock capacity of the headwaters area of the Yellow River decreased by 518.36 thousand sheep units. Soil nutrients showed a similar pattern, soil nutrient loss was greater from 1985–1995 than from 1975–1985. Changes in the overall ecological functionality of the area were not simply a result of a summation of the changes associated with individual evolving landscapes, but rather an integration of positive and negative influences. Landscape evolution occurs in two main directions: degradation and strengthening (expanding and improving). An understanding of the direction, force and integration of parameters influencing landscape evolution as it impacts the attending ecosystems can allow one to foresee how the landscape of the Yellow River source area will evolve in the coming years. This revised version was published online in July 2006 with corrections to the Cover Date.     

Landscape ecology meets landscape science

Landscape ecology is a broad field in a patchwork of related disciplines. Giving landscape ecology a definition and delimiting it from related research areas is both a challenge and a necessity. Past endeavors have focused on expert opinions, analyses of published papers, and conference proceedings. We used a mix of all three, including a unique keyword analysis in two leading landscape-related journals, to highlight latest developments in landscape ecology between 2010 and 2013. Our analysis confirms the key topics of Wu (Landscape Ecol 28(1):1–11, 2013), and suggests that of those connectivity is dominating in terms of research output. However, we also found evidence that the borders of the journal Landscape Ecology are fuzzier than sketched in recent publications. There is a large overlap with the journal Landscape and Urban Planning, and in general a growing weight of conservation, landscape management, and planning related issues in the landscape ecology community. We conclude by encouraging the continued inclusion and strengthening of socio-ecological hot topics such as urban studies and landscape-human interactions in landscape ecological studies and subsequently in the journal landscape ecology.     

Landscape structure influences avian malaria ecology in the Western Cape, South Africa

A central theme in landscape ecology is that of understanding the consequences of landscape heterogeneity for ecological processes. The effects of landscape heterogeneity on parasite communities are poorly understood, although it has been shown that anthropogenic impacts may contribute to outbreaks of both parasites and pathogens. We tested for effects of landcover type, composition, configuration, and urbanisation on avian diversity and avian malaria prevalence in 26 communities of wetland-associated passerines in the Western Cape of South Africa. We predicted that avian malaria prevalence would be influenced by the pattern of farmland and urban areas in the surrounding landscapes and the sizes of the wetlands in which birds were sampled. We quantified landscape pattern using a six-class simplification of the National Landcover data set at 35 × 35 m resolution and five extents of between 1 and 20 km from each wetland. The bird community was sampled using point counts and we collected blood samples from birds at each site. We screened these for malaria using PCR and molecular techniques. Passerine species richness and infection prevalence varied significantly between different landcover types. Host richness and parasite prevalence were highest in viticultural and cropping sites respectively and lowest in urban sites. Wetlands located in indigenous vegetation had intermediate numbers of bird species and intermediate parasite prevalence. Landscape composition and habitat type surrounding wetlands emerged as useful correlates of infection prevalence. Anthropogenic landscape modification appears to have both direct and indirect effects on avian communities and their associated parasite assemblages, with attendant consequences for avian health.     

Spatial resilience: integrating landscape ecology,resilience, and sustainability

Landscape ecology has a high potential to contribute to sustainability in the interactions of people and nature. Landscape ecologists have already made considerable progress towards a more general understanding of the relevance of spatial variation for ecosystems. Incorporating the complexities of societies and economies into landscape ecology analyses will, however, require a broader framework for thinking about spatial elements of complexity. An exciting recent development is to explicitly try to integrate landscape ecology and ideas about resilience in social–ecological systems through the concept of spatial resilience. Spatial resilience focuses on the importance of location, connectivity, and context for resilience, based on the idea that spatial variation in patterns and processes at different scales both impacts and is impacted by local system resilience. I first introduce and define the concepts of resilience and spatial resilience and then discuss some of their potential contributions to the further interdisciplinary integration of landscape ecology, complexity theory, and sustainability science. Complexity theorists have argued that many complex phenomena, such as symmetry-breaking and selection, share common underlying mechanisms regardless of system type (physical, social, ecological, or economic). Similarities in the consequences of social exclusion and habitat fragmentation provide an informative example. There are many strong parallels between pattern–process interactions in social and ecological systems, respectively, and a number of general spatial principles and mechanisms are emerging that have relevance across many different kinds of system. Landscape ecologists, with their background in spatially explicit pattern–process analysis, are well placed to contribute to this emerging research agenda.     

Remote Sensing in Landscape Ecology: Experiences and Perspectives in a European Context

That the relationship between remote sensing and landscape ecology is significant is due in large part to the strong spatial component within landscape ecology. However it is nevertheless necessary to have frequent overview of the interface between remote sensing and landscape ecology, particularly in the light of developments in the types of image data and techniques. The use of remote sensing within European landscape ecology provides a rich range of examples of the interface, including application of some of the latest types of image data. This paper is an overview of the interface that remote sensing has with European landscape ecology, with seven examples of the application of image data in European landscape ecology and examination of associated landscape classification issues. These examples are discussed in terms of the trends and the different roles for image data in landscape ecology that they illustrate, and in particular their classificatory and informational implications. It is suggested that with regard to classification there is a need for re-examination of the roles of image data.     

Landscape ecology as a foundation for sustainable conservation

Landscape ecology and conservation share a common focus on places, but they differ in their perspectives about what is important about those places, and the integration of landscape ecology into conservation is far from complete. I consider four ways in which landscape ecology can contribute to conservation. First, protected areas that are established for conservation are not stand-alone isolates. They exist in the context of broader landscape mosaics, which may encourage or discourage movements of individuals into and out of an area. Second, the landscape surroundings of a preserve may contain threats to the biodiversity within the preserve, many of them consequences of human activities. In combination, these relationships with the surroundings may make the “effective area” of a preserve different from that shown on a map. Third, the scale of an administrative area or of management action may not coincide with the scales of populations, disturbances, or ecological processes, creating challenges to both landscape ecology and conservation. Finally, landscapes encompass people and their activities; sustainability of conservation requires consideration of the tradeoffs between human uses and the biodiversity values of a landscape. I illustrate these four themes with a case study of the management of prairie dogs (Cynomys ludovicianus) in the Great Plains of North America, where the tensions between conservation and human land uses are particularly high. Ecologists and conservationists consider prairie dogs as keystone species in these grassland ecosystems and primary targets for conservation, but many private landowners regard them as varmints that consume valuable livestock forage and degrade rangeland condition. Effective conservation of functioning grasslands must include prairie dogs, and this in turn requires that the issues be addressed in terms of the biological, social, and cultural features of entire landscapes. Important as they are, areas protected for conservation cannot by themselves stem the tide of global biodiversity loss. The perspective must be broadened to include the landscapes where people live and work, recognizing the dynamic nature of landscapes and the factors driving land-use change. Landscape ecologists must work together to overcome the cultural differences between their disciplines, and between academic science and conservation practice and management. It can, and must, be done.     

The shapes of adaptation: Historical ecology of anthropogenic landscapes in the southeastern United States

Native inhabitants of the Southeastern United States traditionally practiced land management strategies, including burning and clearing, that created ‘anthropogenic landscapes’. From the viewpoint of landscape ecology, analysis of historic documents including drawings and deerskin maps from the sixteenth, seventeenth and eighteenth centuries depicted the Native Southeastern landscape as a series of circular patches surrounded by buffer areas. This character contrasted sharply with early European coastal settlements which were more typically rectangular in shape. Differences between Native American and European land use patterns and implied perceptions of the landscape reflect distinct differences in their respective cultural models and intentionality.     

Interdisciplinarity,landscape ecology and the `Transformation of Agricultural Landscapes'

The theme, the `Transformation of Agricultural Landscapes' is used as a context for examining the current status of landscape ecology and its ability to provide a critical set of responses to a defined range of environmental issues. The links between academic structures and the public demand for landscape-based information raises the potential for landscape ecology to provide solutions. Current approaches within landscape ecology are examined and the dominance of the interdisciplinary approach is found to be deficient. A solution is for the land(scape) system itself to become the initial focus of landscape research. A land system has its own systematic properties which extend beyond the biological dominance of ecosystem science which to many is the basis for landscape ecology. For knowledge of the landscape itself to emerge, landscape ecology must develop more as a discipline with its own theoretical bases and foci than as an interdisciplinary area.     

The impacts of historical land-use and landscape variables on hollow-bearing trees along an urbanisation gradient

Hollow-bearing trees provide habitat for diverse taxonomic groups and as such they are recognised for their importance globally. There is, however scant reference to this resource relative within urban forest patches. The functional ecology of habitat remnants along an urbanisation gradient plays an important ecological, social and economic role within urban landscapes. Here we quantify the impacts of urbanisation, landscape, environmental, disturbance (past and present) and stand variables on hollow-bearing tree density within urban forest patches. This was undertaken by surveying 45 forest patches on the Gold Coast, south-east Queensland, Australia. Sites were categorised as; urban, peri-urban or rural along an urbanisation gradient, with an additional five control sites. Historical logging practices were found to be the driving factor influencing hollow-bearing tree density along the urbanisation gradient; while the impacts of urbanisation itself are not as yet discernible. These findings highlight the significance of incorporating historical land use practise into current and future urban planning, as these will have continuing impacts on remaining urban biodiversity values. These findings, will benefit natural resource managers and urban planners when making decisions about where and how best to manage for hollow-bearing trees along urbanisation gradients.     

Influence of landscape structure on reef fish assemblages

Management of tropical marine environments calls for interdisciplinary studies and innovative methodologies that consider processes occurring over broad spatial scales. We investigated relationships between landscape structure and reef fish assemblage structure in the US Virgin Islands. Measures of landscape structure were transformed into a reduced set of composite indices using principal component analyses (PCA) to synthesize data on the spatial patterning of the landscape structure of the study reefs. However, composite indices (e.g., habitat diversity) were not particularly informative for predicting reef fish assemblage structure. Rather, relationships were interpreted more easily when functional groups of fishes were related to individual habitat features. In particular, multiple reef fish parameters were strongly associated with reef context. Fishes responded to benthic habitat structure at multiple spatial scales, with various groups of fishes each correlated to a unique suite of variables. Accordingly, future experiments should be designed to test functional relationships based on the ecology of the organisms of interest. Our study demonstrates that landscape-scale habitat features influence reef fish communities, illustrating promise in applying a landscape ecology approach to better understand factors that structure coral reef ecosystems. Furthermore, our findings may prove useful in design of spatially-based conservation approaches such as marine protected areas (MPAs), because landscape-scale metrics may serve as proxies for areas with high species diversity and abundance within the coral reef landscape.

     

Pond density as a determinant of aquatic species richness in an urban landscape

Green spaces within urban areas provide services and benefits to human populations and habitat for a variety of species. Freshwater, in the form of rivers, canals, lakes, reservoirs and ponds, is an important component of urban greenspaces. This paper focuses on ponds; and specifically ponds within urban areas. This work is timely as during 2008 ponds were designated, in the UK, as habitats of national conservation importance. Yet, while farmland ponds have received considerable attention, there has been little work on the ecology and landscape ecology of urban ponds. Ecological data was collected from 37 ponds in the Borough of Halton (northwest England) over a period of 2 years (2005–2006). The median species richness in these ponds was 28 invertebrate species and 10 macrophyte species. A highly significant correlation was observed between pond density and species richness. The relationship between the richness of different taxa varied according to scale; becoming more significant within pond clusters than within a single pond. These findings have significance for those involved in planning and managing urban environments, further strengthening the need for functional ecological connectivity in urban areas. With pressure to increase infill development, and thus raise housing density, a greater understanding of the affect of urban design on pond ecology will be of importance to urban planners and ecologists alike.     

Effects of land-cover change on spatial pattern of forest communities in the Southern Appalachian Mountains (USA)

Landscape Ecology - Understanding the implications of past, present and future patterns of human land use for biodiversity and ecosystem function is increasingly important in landscape ecology. We...     

The Eco-field Hypothesis: Toward a Cognitive Landscape

Cognition is recognized as an essential component of the living strategies of organisms and the use of cognitive approaches based on an organismic-centered-view is discussed as a strategy to aid the advancement of landscape ecology to a more independent scientific discipline. The incorporation of the theory of information, the theory of meaning and the Umwelt, and the biosemiotic models into the landscape ecology framework is described as the necessary step to create a common paradigmatic background and operational tools to develop basis for a cognitive landscape ecology. Three cognitive landscapes (neutrality-based landscape, individual-based landscape and observer-based landscape) have been described as the result of distinctive mechanisms to extract information from a cognitive matrix based on a growing literature of (bio)semiotic exchange. The eco-field hypothesis is presented as a new possibility to describe landscape processes according to an organismic-centered-view. The eco-field is defined as a spatial configuration carrier of a specific meaning perceived when a specific living function is activated. A species-specific cognitive landscape is composed of all the spatial configurations involved for all the living functions for a particular organism. Eco-field hypothesis offers a detailed vision of (habitat) environmental requirements and creates a novel conceptual bridge between niche, habitat, Umwelt and the methodological approaches of spatial ecology. Finally the eco-field hypothesis promises a new testing ground for experimental investigations in landscape ecology and in related disciplines including environmental psychology, cognitive ethology, cultural ecology, landscape aesthetics, design and planning.     

Addressing the interplay of poverty and the ecology of landscapes: a Grand Challenge Topic for landscape ecologists?

We argue for the landscape ecology community to adopt the study of poverty and the ecology of landscapes as a Grand Challenge Topic. We present five areas of possible research foci that we believe that landscape ecologists can join with other social and environmental scientists to increase scientific understanding of this pressing issue: (1) scale and poverty; (2) landscape structure and human well-being; (3) social and ecological processes linked to spatial patterns in landscapes; (4) conservation and poverty, and (5) applying the landscape ecologist’s toolkit. A brief set of recommendations for landscape ecologists is also presented. These include the need to utilize broad frameworks that integrate social and ecological variables, build capacity to do this kind of work through the development of strong collaborations of researchers in developed and developing countries, create databases in international locations where extreme poverty exists, and create a new generation of researchers capable of addressing this pressing social and environmental issue.     

Coupling past management practice and historic landscape change on John F. Kennedy Space Center,Florida

Historic landcover dynamics in a scrubby flatwoods (Tel-4) and scrub landscape (Happy Creek) on John F. Kennedy Space Center were measured using aerial images from 1943, 1951, 1958, 1969, 1979, and 1989. Landcover categories were mapped, digitized, geometrically registered, and overlaid in ARC/INFO. Both study sites have been influenced by various land use histories, including periods of range management, fire suppression, and fire management. Several analyses were performed to help understand the effects of past land management on the amount and spatial distribution of landcover within the study sites. A chi-squared analysis showed a significant difference between the frequency of landcover occurrence and management period. Markov chain models were used to project observed changes over a 100-year period; these showed current management practices being effective at Tel-4 (restoring historic landscape structure) and much less effective at Happy Creek. Documenting impacts of past management regimes on landcover has provided important insight into current landscape composition and will provide the basis for improving land management on Kennedy Space Center and elsewhere.     

Influence of biophysical factors and differences in Ojibwe reservation versus Euro-American social histories on forest landscape change in northern Wisconsin,USA

Landscape ecology studies have demonstrated that past modifications of the landscape frequently influence its structure, highlighting the utility of integrating historical perspectives from the fields of historical ecology and environmental history. Yet questions remain for historically-informed landscape ecology, especially the relative influence of social factors, compared to biophysical factors, on long-term land-cover change. Moreover, methods are needed to more effectively link history to ecology, specifically to illuminate the underlying political, economic, and cultural forces that influence heterogeneous human drivers of land-cover change. In northern Wisconsin, USA, we assess the magnitude of human historical forces, relative to biophysical factors, on land-cover change of a landscape dominated by eastern white pine (Pinus strobus L.) forest before Euro-American settlement. First, we characterize land-cover transitions of pine-dominant sites over three intervals (1860–1931; 1931–1951; 1951–1987). Transition analysis shows that white pine was replaced by secondary successional forest communities and agricultural land-covers. Second, we assess the relative influence of a socio-historical variable (“on-/off-Indian reservation”), soil texture (clay and sand), and elevation on land-cover transition. On the Lake Superior clay plain, models that combine socio-historical and biophysical variables best explain long-term land-cover change. The socio-historical variable dominates: the magnitude and rate of land-cover change differs among regions exposed to contrasting human histories. Third, we developed an integrative environmental history-landscape ecology approach, thereby facilitating linkage of observed land-cover transitions to broader political, economic, and cultural forces. These results are relevant to other landscape investigations that integrate history and ecology.     

Soundscape in a context of acoustic and landscape ecology

Soundscape ecology is being proposed as a new synthesis that leverages two important fields of study: landscape ecology and acoustic ecology. These fields have had a rich history. Running “in parallel” for over three decades now, soundscape ecology has the potential to unite these two (among other) fields in ways that provide new perspectives on the acoustics of landscapes. Each of us was involved in the “birth” of these two fields. We each reflect here on the rich history of landscape ecology and acoustic ecology and provide some thoughts on the future of soundscape ecology as a new perspective.     

Landscape Ecology – towards a unified discipline?

Contemporary landscape ecology is not unified at all.There are historical, geographical and biological reasons for the lack of unification, as well as differences between science and application. The search for a unified theory of landscape ecology should consider previous concepts such as ‘landscape diagnosis’ and ‘landscape functions’ which were elaborated in Central Europe. Because of the various aspects in a landscape (components, processes, relations), landscape ecology should be regarded as a multidisciplinary, better a transdisciplinary, science where different views and approaches are involved in a holistic manner. The principle of complementarity is helpful to understand and describe the landscape. As a crucial step, the transformation of natural science categories to categories of the human society is brought out. This is realized by land(scape) evaluation and by the elaboration of goals (visions) of landscape development.This revised version was published online in May 2005 with corrections to the Cover Date.     

Teaching landscape ecology: the importance of field-oriented,inquiry-based approaches

Context

Landscape ecology has traditionally been taught through theoretical classes or computer labs. On the other hand, field labs have been generally less used as a way of teaching landscape ecology concepts.

Objectives

We show that field labs with an inquiry-based approach, where students are involved in the investigation, are feasible for training students in landscape ecology. We evaluated how common field labs are in landscape ecology courses, and also their contribution for student learning.

Methods

We evaluated whether field labs are used in landscape ecology courses by scanning available syllabi. We also used outcomes from a course offered in Brazil to show how field labs can be integrated into landscape ecology courses.

Results

Only 18.2 % of the 44 syllabi we found had field labs. The case study developed in Brazil showed that field labs allowed students to develop important skills, including the ability to design field studies, choose appropriate scales of analysis, detect ecological patterns, and judge multiple hypotheses.

Conclusions

Field labs are still uncommon in landscape ecology courses, but they can be a useful tool to teach landscape ecology concepts and to help students developing the necessary skills to do research. We offer recommendations regarding how to incorporate field labs in landscape ecology courses.