Spatial Resilience Research Articles

Spatial Resilience of Outdoor Domestic Space in Mozambique

Historically, the people of Mozambique have faced oppression and social spatial segregation and responded in a way that has reinforced rather than dismantled their traditional values. Since pre-colonial times, the population’s strategy for escaping from environmental and foreign political disruption has been to reinvent tradition, based on the principles of resilience, resistance and self-reliance. The development of decentralised human settlements, involving the appropriation of land for domestic space and the self-organisation of neighbourhoods, were strategies to protect communities from adversity and secure collective self-reliance. Following Mozambique’s conversion to globalization, the post-colonial ‘cement city’ is now the core of neo-liberalism, as a node of the global economy, where foreign donors and international market economy control national political economy, exacerbating the premise of the negation of self-sufficiency that continues to evolve resiliently at its margins. The adoption of a neo-liberal model of development during the 1990s, completely bypasses the realities of Mozambican society. This paper argues that the strategy of self-production of space regarding the household/Outdoor Domestic Space unit, which existed previously as a resistance strategy, first of all against colonialism and secondly, against the statist definition of socialism, thirdly, has become a successful strategy for survival, as the building block of the decentralised Agrocity, in the face of a global economy which totally neglects both the people and the land. Outdoor Domestic Space is a multifaceted space that refers to the external space surrounding the built house and which, in the case of Mozambique, is where daily life takes place, involving strong social, ecological and productive functions. Under successive periods of political economy oppression and environmental adversity, the Outdoor Domestic Space has been adapted and refined to ensure collective self-reliance. Shaping a green and ruralised urbanisation at the margins of the Mozambican post-colonial dualistic city, which I call the Agrocity, the Outdoor Domestic Space is resilient because it is able to adjust domestic space as a strategy to secure livelihoods, provide urban food, commerce and services, maintain vital kinship relationships and produce a comfortable and clean microclimate across the spontaneous neighbourhoods. This spatial resilience is the feature underlying the self-organisation of neighbourhoods with a new way of overcoming alienation from nature, which suggest the continuance of an innate relationship between society, the human habitat and nature.

How far do schools of roving herbivores rove? A case study using Scarus rivulatus

Herbivorous reef fish play an important role in shaping ecosystem processes on coral reefs. Often found in schools, Scarus rivulatus, is an abundant herbivorous species on the Great Barrier Reef (GBR), Australia, especially on inshore reefs. Recent evidence has highlighted the limited spatial movements of some herbivorous fishes. However, individuals in schools are thought to be much more mobile. The aim of this study, therefore, was to evaluate the spatial range of schooling S. rivulatus to measure the spatial scale over which they exert their functional role. Furthermore, we assess the influence of the schooling behaviour on their feeding rates and thus their ecological impact. The diurnal movements of S. rivulatus were monitored using acoustic transmitters and a passive acoustic array for up to 7 months in Pioneer Bay, Orpheus Island, GBR. In addition, behavioural observations recorded school size-frequency distributions and feeding rates of S. rivulatus inside and outside foraging schools. Despite schooling, all S. rivulatus were site attached. On average, the maximum potential home range of individuals was 24,440 m2 and ranges overlapped extensively in individuals captured from the same school. School size was highly variable, with a mean school size of 5.7 individuals. Schooling had a significant impact on the functional role of individuals, with feeding rates in schools being two times higher for S. rivulatus and over three times higher for other scarid species. Our results suggest that, despite schooling, individual S. rivulatus only rove over a limited area of reef (occupying a linear stretch of reef, measuring only approximately 250 m for individuals and 220 m for entire schools). Each individual may therefore have little impact on the spatial resilience of coral reefs.

Highlighting order and disorder in social–ecological landscapes to foster adaptive capacity and sustainability

Landscape sustainability can be considered in terms of order and disorder, where order implies causality, well-defined boundaries and predictable outcomes, while disorder implies uncertain causality, shifting boundaries and often-unpredictable outcomes. We address the interplay of order and disorder in social–ecological landscapes (SELs) using spatiotemporal analysis of entropy-related indices of Normalized Difference Vegetation Index time-series. These indices can provide insights for complex systems analysis for the evaluation of adaptive capacity in SELs. In particular, our overarching aim is to help interpret what an increase of order/disorder means with regards to SELs and the underlying drivers and causes of conditions in SELs. The approach can be used to increase spatially explicit anticipatory capability in environmental science and natural resource management based on how the system has responded to stress in the past. Such capability is crucial to address SEL adaptive capacity and for sustainable planning given that surprises may increase as a consequence of both climate change and multiple interacting anthropogenic stressors. These advancements should greatly contribute to the application of spatial resilience strategies in general, and to sustainable landscape planning in particular, and for the spatially explicit adaptive comanagement of ecosystem services.

Spatial and Social Resilience in Phnom Penh, Cambodia since 1979

This article assimilates the city of Phnom Penh into an open system that has spread into the Mekong River flood plain with the backfilling of tidelands and the building of successive dykes. The city's hydraulic networks were damaged by the major crisis suffered under the Khmer Rouge characterized by a strong de-urbanization process. Since 1979, the progressive restoration of institutions, in addition to ad hoc interventions in the city's networks by ‘pioneer actors’, allowed vertical interactions in the city-system between stakeholders and structures to redevelop, and also permitted horizontal interactions between structures. Despite more recent crises, the city-system has proved resilient and it maintains its dualistic kernel–margins structure.

Spatial distribution patterns and population structure of the sea urchin <i>Paracentrotus lividus</i> (Echinodermata: Echinoidea), in the coastal fishery of western Sardinia: a geostatistical analysis

The identification of appropriate spatial distribution patterns for the observation, analysis and management of stocks with a persistent spatial structure, such as sea urchins, is a key issue in fish ecology and fisheries research. This paper describes the development and application of a geostatistical approach for determining the spatial distribution and resilience of the population of the sea urchin Paracentrotus lividus in a fishing ground of western Sardinia (western Mediterranean). A framework combining field data collection, experimental modelling and mapping was used to identify the best-fit semivariogram, taking pre-fishing and post-fishing times into consideration. Variographic analyses indicate autocorrelation of density at small distances, while the isotropic Gaussian and spherical models are suitable for describing the spatial structure of sea urchin populations. The point kriging technique highlights a generally patchy population distribution that tends to disappear during the fishing season. Kriging maps are also useful for calculating predictable stock abundances, and thus mortality rates, by class diameters within six months of fishing. We conclude that the framework proposed is adequate for biomass estimation and assessment of sea urchin resources. This framework can therefore be regarded as a useful tool for encouraging a science-based management of this fishery.

Design and Analysis of Distributed Radar Sensor Networks

In this paper, we design a network of distributed radar sensors that work in an ad hoc fashion, but are grouped together by an intelligent clusterhead. This system is named Radar Sensor Network (RSN). A RSN not only provides spatial resilience for target detection and tracking compared to traditional radars, but also alleviates inherent radar defects such as the blind speed problem. This interdisciplinary area offers a new paradigm for parallel and distributed sensor research. We propose both coherent and noncoherent RSN detection systems applying selection combination algorithm (SCA) performed by clusterhead to take the advantage of spatial diversity. Monte Carlo simulations show that proposed RSN can provide much better detection performance than that of single radar sensor for fluctuating targets, in terms of probability of false alarm and miss detection. We also analyze the impact of Doppler shift on both coherent and noncoherent RSN detection systems at the presence of clutter. The result is that the coherent system is more robust to the noncoherent RSN.

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.

Degradation of the crocodile population in the Olifants River Gorge of Kruger National Park, South Africa

Abstract Top predators such as crocodiles often reflect ecosystem degradation. The recent spate of close to 200 Nile crocodile deaths may reflect the ecosystem state of the Olifants–Letaba River system in the Kruger National Park. This paper investigates whether the crocodile deaths were indeed the consequence of a rare and perhaps acute event given the variability in annual population growth rates of crocodilians. Spotlight‐ and helicopter‐based surveys designed to correct for availability and detectability bias were used to estimate population sizes of crocodiles from 2008 to 2010 in and around the Olifants River Gorge, the focal area of crocodile deaths. Correction factors derived from individually observed crocodiles for both spotlight‐ and helicopter‐based counts were lower than those typically used for Nile crocodiles as well as other crocodile species. Even so, corrected spotlight‐ and helicopter‐based estimates were comparable and the number of crocodiles in the focal study area declined significantly from 780 (95% CI: 637–1222) to between 460 (spotlight estimate, 95% CI 375–665) and 505 (aerial estimate, 95% CI: 559–1746) during the period of crocodile deaths. The average annual decline of 35% was at the lower end of the distribution of annual population growth rates across the rivers of Kruger National Park. The crocodile deaths reflect a possible rare event that suggests a degraded crocodile population, possibly the consequences of broad‐scale cascades of environmental deterioration of the Olifants–Letaba River system. Even so, the potential risk of local demise of the population in the focal study area in the short term may be diminished through evolutionary, demographic and spatial resilience inherent within crocodiles that can accommodate the as yet unknown disease dynamics of pansteatitis. Copyright © 2011 John Wiley & Sons, Ltd.

Resilience and climate change: lessons from coral reefs and bleaching in the Western Indian Ocean

The impact of climate change through thermal stress-related coral bleaching on coral reefs of the Western Indian Ocean has been well documented and is caused by rising sea water temperatures associated with background warming trends and extreme climate events. Recent studies have identified a number of factors that may reduce the impact of coral bleaching and mortality at a reef or sub-reef level. However, there is little scientific consensus as yet, and it is unclear how well current science supports the immediate needs of management responses to climate change. This paper provides evidence from the Western Indian Ocean in support of recent hypotheses on coral and reef vulnerability to thermal stress that have been loosely termed ‘resistance and resilience to bleaching’. The paper argues for a more explicit definition of terms, and identifies three concepts affecting coral-zooxanthellae holobiont and reef vulnerability to thermal stress previously termed ‘resistance to bleaching’: ‘thermal protection’, where some reefs are protected from the thermal conditions that induce bleaching and/or where local physical conditions reduce bleaching and mortality levels; ‘thermal resistance’, where individual corals bleach to differing degrees to the same thermal stress; and ‘thermal tolerance’, where individual corals suffer differing levels of mortality when exposed to the same thermal stress. ‘Resilience to bleaching’ is a special case of ecological resilience, where recovery following large-scale bleaching mortality varies according to ecological and other processes. These concepts apply across multiple levels of biological organization and temporal and spatial scales. Thermal resistance and tolerance are genetic properties and may interact with environmental protection properties resulting in phenotypic variation in bleaching and mortality of corals. The presence or absence of human threats and varying levels of reef management may alter the influence of the above factors, particularly through their impacts on resilience, offering the opportunity for management interventions to mitigate the impacts of thermal stress and recovery on coral reefs. These concepts are compiled within an overarching framework of spatial resilience theory. This provides a framework for developing linked scientific and management questions relating to the larger scale impacts of climate change on coral reefs, their management needs and prospects for their future.

Reserves, resilience and dynamic landscapes.

In a world increasingly modified by human activities, the conservation of biodiversity is essential as insurance to maintain resilient ecosystems and ensure a sustainable flow of ecosystem goods and services to society. However, existing reserves and national parks are unlikely to incorporate the long-term and large-scale dynamics of ecosystems. Hence, conservation strategies have to actively incorporate the large areas of land that are managed for human use. For ecosystems to reorganize after large-scale natural and human-induced disturbances, spatial resilience in the form of ecological memory is a prerequisite. The ecological memory is composed of the species, interactions and structures that make ecosystem reorganization possible, and its components may be found within disturbed patches as well in the surrounding landscape. Present static reserves should be complemented with dynamic reserves, such as ecological fallows and dynamic successional reserves, that are part of ecosystem management mimicking natural disturbance regimes at the landscape level.

Spatial Resilience of Coral Reefs

There have been several earlier studies that addressed the influence of natural disturbance regimes on coral reefs. Humans alter natural disturbance regimes, introduce new stressors, and modify background conditions of reefs. We focus on how coral reef ecosystems relate to disturbance in an increasingly human-dominated environment. The concept of ecosystem resilience—that is, the capacity of complex systems with multiple stable states to absorb disturbance, reorganize, and adapt to change—is central in this context. Instead of focusing on the recovery of certain species and populations within disturbed sites of individual reefs, we address spatial resilience—that is, the dynamic capacity of a reef matrix to reorganize and maintain ecosystem function following disturbance. The interplay between disturbance and ecosystem resilience is highlighted. We begin the identification of spatial sources of resilience in dynamic seascapes and exemplify and discuss the relation between “ecological memory” (biological legacies, mobile link species, and support areas) and functional diversity for seascape resilience. Managing for resilience in dynamic seascapes not only enhances the likelihood of conserving coral reefs, it also provides insurance to society by sustaining essential ecosystem services.

Error-resilient transcoding for video over wireless channels

We describe a method to maintain quality for video transported over wireless channels. The method is built on three fundamental blocks. First, we use a transcoder that injects spatial and temporal resilience into an encoded bitstream. The amount of resilience is tailored to the content of the video and the prevailing error conditions, as characterized by bit error rate. Second, we derive analytical models that characterize how corruption propagates in a video that is compressed using motion-compensated encoding and subjected to bit errors. Third, we use rate distortion theory to compute the optimal allocation of bit rate among spatial resilience, temporal resilience, and source rate. Furthermore, we use the analytical models to generate the resilience rate distortion functions that are used to compute the optimal resilience. The transcoder then injects this optimal resilience into the bitstream. Simulation results show that using a transcoder to optimally adjust the resilience improves video quality in the presence of errors while maintaining the same input bit rate.