Disturbance, patches and mosaics

2021 ◽  
pp. 33-46
Author(s):  
Simon F. Thrush ◽  
Judi E. Hewitt ◽  
Conrad A. Pilditch ◽  
Alf Norkko
Keyword(s):  
Critical Factor ◽  
Patch Dynamics ◽  
Landscape Scale ◽  
Soft Sediment ◽  
Heterogeneous Landscapes ◽  
Recovery Processes ◽  
Local Recovery ◽  
Metacommunity Dynamics ◽  
Patch Scale ◽  
Disturbance Recovery

This chapter introduces the range of biological and physical processes that disturb soft sediment. It introduces the concept of disturbance regimes that connect the extent, frequency and magnitude of disturbance. Post-disturbance recovery processes are described in terms of processes that occur within the disturbed patch and processes that influence recovery from outside the patch. Moving on from the patch scale, the chapter introduces the concept of patch dynamics and the concept of the seafloor as a mosaic of patches at different stages of recovery from disturbance. Connectivity between patches is a critical factor linking local recovery processes to landscape-scale processes. This mosaic perspective leads to the introduction of metacommunity dynamics and the potential for heterogeneous landscapes to fragment and eventually homogenise seafloor communities as a consequence of the loss of large habitat-defining species.

Relationships between macroinfaunal invertebrates and physicochemical factors in two sandy beaches of Patagonia

2009 ◽  
Vol 90 (3) ◽  
pp. 429-435 ◽  
Author(s):  
María Martha (Pitu) Mendez ◽  
Evangelina Schwindt ◽  
Alejandro Bortolus
Keyword(s):  
Grain Size ◽  
National Park ◽  
Organic Matter Content ◽  
Benthic Fauna ◽  
Physicochemical Characteristics ◽  
Landscape Scale ◽  
Sandy Beaches ◽  
Matter Content ◽  
Soft Sediment ◽  
Physicochemical Factors

The interest in the knowledge of the ecology of soft-sediment communities is increasing due to the importance that these environments pose to ecologists and environmentalists. However, the ecology of Argentinean sandy beaches is almost unknown, in spite of being relatively common landscapes. In this work we describe and compare the macroinfaunal assemblages in the two largest sandy beaches within the Monte León National Park, the first marine-coastal park of Argentina. Macrobenthic samples were collected and environmental descriptions were performed by quantifying and comparing the organic matter content, grain size distribution and depth of the substratum available for macroinfaunal colonization. Results show that polychaetes and crustaceans are the dominant taxa and that the two beaches differ in the physicochemical characteristics, suggesting that a relation between the benthic fauna and physicochemical factors exists. Although they appeared similar at the landscape scale in preliminary visual surveys, the geomorphological differences between habitats are likely to drive strong differences in the structure of the macroinfaunal assemblages. The monitoring of visible landscape features is likely to undermine the efficiency of protection and managing strategies if not complemented by geomorphological and ecological surveys of less visible ecosystem variables.

Landscape ecology and conservation: moving from description to application

1994 ◽  
Vol 1 (3) ◽  
pp. 170 ◽  
Author(s):  
Richard J. Hobbs
Keyword(s):  
Landscape Ecology ◽  
Conservation Biology ◽  
Conservation Management ◽  
Patch Dynamics ◽  
Single Species ◽  
Landscape Scale ◽  
Metapopulation Dynamics ◽  
Quantitative Methodology ◽  
Effective Conservation ◽  
Conservation Of Biodiversity

The focus of conservation biology has been predominantly the study of single species, and conservation management and legislation has been directed mostly at the species level. Increasingly, however, there has been a recognition that ecosystems and landscapes need to be considered, since they form the physical and biotic context within which species exist. Increased emphasis on the landscape scale suggests that the emerging discipline of landscape ecology might have much to offer conservation biology. Landscape ecology is still a young science with no well-defined theoretical framework and little rigorous quantitative methodology. It aims to study patterns, processes and changes at the scale of hectares to square kilometers. Its focus on the pattern and dynamics of ecosystems or patches within a landscape offers much which is of relevance to conservation biology. Topics such as disturbance, patch dynamics, metapopulation dynamics, landscape flows, connectivity and fragmentation all have relevance to the conservation of biodiversity in natural, altered and rapidly changing systems. The papers in this issue provide a cross section of Australian research into landscape ecology which is of relevance to conservation biology. Methodological, theoretical and practical aspects are covered. I suggest that effective conservation of biodiversity will be achieved only if the landscape context is taken into account.

Dynamic hypergraphs of renewal processes in mobile networks.

2021 ◽  
Vol 5 ◽  
Author(s):  
A.I. Mikov ◽  
◽  
A.A. Mikov
Keyword(s):  
Computer Networks ◽  
Mobile Networks ◽  
Computer Network ◽  
Probability Distributions ◽  
Operation Time ◽  
Recovery Processes ◽  
Geometric Configurations ◽  
Network Operation ◽  
Local Recovery ◽  
Geometric Hypergraphs

The characteristics of random geometric hypergraphs are studied as mathematical models of scalable wireless computer networks. An efficient algorithm for finding cliques in geometric graphs, constructing hypergraphs from geometric configurations has been developed. The types of hyper-edges in hypergraphs generated by a scalable configuration have been identified. The influence of random failures of nodes of computer networks and their restorations on the dynamics of hypergraphs of networks is considered. The analysis of the dynamics of the number of active nodes depending on the type of probability distributions of uptime and recovery time is carried out. The dependences of the mathematical expectation of the number of hyper-edges of certain types in the geometric hypergraph of a wireless computer network on the network operation time, on the radii of zones of reliable reception / transmission of a signal, on the ratio of the parameters of local recovery processes are obtained. The presentation of the results is accompanied by charts.

Restoration of soft-sediment habitats

2021 ◽  
pp. 179-190
Author(s):  
Simon F. Thrush ◽  
Judi E. Hewitt ◽  
Conrad A. Pilditch ◽  
Alf Norkko
Keyword(s):  
Natural History ◽  
Management Strategies ◽  
Ecosystem Processes ◽  
Soft Sediment ◽  
Positive Interventions ◽  
Critical Part ◽  
Recovery Processes ◽  
Active Restoration ◽  
History Of

The final chapter addresses positive interventions that can help reverse the decline in soft-sediment ecosystems. Restoration draws on our understanding of ecosystem processes and the natural history of soft-sediment organisms. The chapter describes how active restoration can be designed to overcome bottlenecks that slow natural recovery processes and to form a critical part of integrative management strategies, such as ecosystem-based management. The chapter describes the what, why, where and how of active restoration, with a focus on the restoration of shellfish reefs, one of the most impacted soft-sediment habitats. Links between restoration and remediation are made to emphasise the importance of ecosystem function in generating positive changes in soft-sediment habitats. As restoration is likely to involve different elements of society in trying to fix problems, it is important that we develop effective ways of measuring success. The chapter ends by touching on the potential to generate new restoration economies, recognising that restoring nature can be at least as economically beneficial as developing more grey infrastructure.

The sedimentary environment

2021 ◽  
pp. 3-18
Author(s):  
Simon F. Thrush ◽  
Judi E. Hewitt ◽  
Conrad A. Pilditch ◽  
Alf Norkko
Keyword(s):  
Turbulent Flows ◽  
Sedimentary Environment ◽  
Critical Factor ◽  
Ecosystem Functions ◽  
Soft Sediment ◽  
Earth System ◽  
Hydrodynamic Conditions ◽  
Habitat Variation ◽  
Laminar And Turbulent Flows

This chapter introduces the roles of sediment properties and hydrodynamic conditions in influencing soft-sediment communities. It identifies environmental factors that are commonly used to characterise soft-sediment habitats and used to tease out the role of habitat variation from other factors that influence populations and communities. The differences between cohesive and non-cohesive sediments that profoundly influence ecosystem functions are described. Hydrodynamics particularly at the sediment–water interface are introduced as a critical factor affecting many ecosystem processes. The chapter introduces the differences in laminar and turbulent flows. Coastal soft sediments in particular are places of high organic matter remineralisation and thus critical for the recycling of primary nutrients and primary production, particularly by microphytobenthos. These factors underpin the important role of marine sediments in biogeochemistry and earth system processes.

scholarly journals Importance of patch scale vs landscape scale on selected forest birds

Oikos ◽  
2002 ◽  
Vol 96 (1) ◽  
pp. 110-118 ◽  
Author(s):  
Michelle Lee ◽  
Lenore Fahrig ◽  
Kathryn Freemark ◽  
David J. Currie
Keyword(s):  
Landscape Scale ◽  
Forest Birds ◽  
Patch Scale

scholarly journals Post-settlement dispersal: the neglected link in maintenance of soft-sediment biodiversity

2015 ◽  
Vol 11 (2) ◽  
pp. 20140795 ◽  
Author(s):  
Conrad A. Pilditch ◽  
Sebastian Valanko ◽  
Joanna Norkko ◽  
Alf Norkko
Keyword(s):  
Human Activities ◽  
Larval Dispersal ◽  
Spatial Scales ◽  
Benthic Communities ◽  
Larval Settlement ◽  
Small Scale ◽  
Soft Sediment ◽  
Species Pools ◽  
And Function ◽  
Metacommunity Dynamics

Seafloor integrity is threatened by disturbances owing to human activities. The capacity of the system to recover from disturbances, as well as maintain resilience and function, depends on dispersal. In soft-sediment systems, dispersal continues after larval settlement, but there are very few measurements of how far the post-settlers disperse in nature. Spatial scales of post-settlement dispersal are, however, likely to be similar to pelagic larval dispersal because of continued, frequent, small-scale dispersal over longer periods. The consequences of this dispersal may be more important for the maintenance of biodiversity and metacommunity dynamics than is pelagic larval dispersal, because of the greater size and competency of the dispersers. We argue that an increased empirical understanding of post-settlement dispersal processes is key for predicting how benthic communities will respond to local disturbances and shrinking regional species pools, with implications for monitoring, managing and conserving biodiversity.

Demographic Aspects of Marine, Soft Sediment Patch Dynamics

1991 ◽  
Vol 31 (6) ◽  
pp. 808-820 ◽  
Author(s):  
ROMAN N. ZAJAC ◽  
ROBERT B. WHITLATCH
Keyword(s):  
Patch Dynamics ◽  
Soft Sediment
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