Landslides in blanket peat on subantarctic islands: Causes, characteristics and global significance

Dykes, Alan P.; Selkirk-Bell, J M

doi:10.1016/j.geomorph.2010.09.002

Cited by 7 publications

(5 citation statements)

References 48 publications

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“…The mesocosm experiment ran for 4 weeks (28 days). Sediment treatments were established on day 1, mimicking a pulse of sediment deposition on riverbed habitat patches that occur in eroding peatlands due to disturbances such as riverbank failures (Crowe & Warburton, ), and larger hillslope slumps or slides (Dykes & Selkirk‐Bell, ; Kokelj et al, ). Macroinvertebrates then colonized the mesocosms via drift, swimming, crawling and aerial oviposition over the 4‐week period.…”

Section: Methodsmentioning

confidence: 99%

Sediment deposition from eroding peatlands alters headwater invertebrate biodiversity

Brown

Aspray

Ledger

et al. 2018

Global Change Biology

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Land use and climate change are driving widespread modifications to the biodiverse and functionally unique headwaters of rivers. In temperate and boreal regions, many headwaters drain peatlands where land management and climate change can cause significant soil erosion and peat deposition in rivers. However, effects of peat deposition in river ecosystems remain poorly understood. We provide two lines of evidence—derived from sediment deposition gradients in experimental mesocosms (0–7.5 g/m2) and headwaters (0.82–9.67 g/m2)—for the adverse impact of peat deposition on invertebrate community biodiversity. We found a consistent negative effect of sediment deposition across both the experiment and survey; at the community level, decreases in density (1956 to 56 individuals per m2 in headwaters; mean 823 ± 129 (SE) to 288 ± 115 individuals per m2 in mesocosms) and richness (mean 12 ± 1 to 6 ± 2 taxa in mesocosms) were observed. Sedimentation increased beta diversity amongst experimental replicates and headwaters, reflecting increasing stochasticity amongst tolerant groups in sedimented habitats. With increasing sedimentation, the density of the most common species, Leuctra inermis, declined from 290 ± 60 to 70 ± 30 individuals/m2 on average in mesocosms and >800 individuals/m2 to 0 in the field survey. Traits analysis of mesocosm assemblages suggested biodiversity loss was driven by decreasing abundance of invertebrates with trait combinations sensitive to sedimentation (longer life cycles, active aquatic dispersal of larvae, fixed aquatic eggs, shredding feeding habit). Functional diversity metrics reinforced the idea of more stochastic community assembly under higher sedimentation rates. While mesocosm assemblages showed some compositional differences to surveyed headwaters, ecological responses were consistent across these spatial scales. Our results suggest short‐term, small‐scale stressor experiments can inform understanding of “real‐world” peatland river ecosystems. As climate change and land‐use change are expected to enhance peatland erosion, significant alterations to invertebrate biodiversity can be expected where these eroded soils are deposited in rivers.

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Section: Methodsmentioning

confidence: 99%

Sediment deposition from eroding peatlands alters headwater invertebrate biodiversity

Brown

Aspray

Ledger

et al. 2018

Global Change Biology

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“…The landscape variations, together with the feedback from mechanical, ecological, and hydrological processes, affect the stresses on the peat body that control the occurrence of failure conditions on the peatland. The peatland failure involving mass movement (Dykes and Selkirk-Bell, 2010;Dykes, 2022;Dykes, 2008) influences the estimation of carbon accumulation on the peatland because it might result in the formation of water channels that facilitate the drainage and oxidation processes (Warburton et al, 2003;Evans and Warburton, 2007). Potentially, this phenomenon could determine the maximum limit to peatland carbon accumulation in a landscape (Large et al, 2021).…”

Section: Limitations and Future Developmentmentioning

confidence: 99%

MPeat2D – A fully coupled mechanical-ecohydrological model of peatland development in two dimensions

Mahdiyasa,

Large,

Icardi

et al. 2023

Preprint

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Abstract. Higher dimensional models of peatland development are required to analyse the influence of spatial heterogeneity and complex feedback mechanisms. However, the current models exclude the mechanical process that leads to uncertainties in simulating the spatial variability of water table position, vegetation composition, and peat physical properties. Here, we propose MPeat2D, a peatland development model in two dimensions, which considers mechanical, ecological, and hydrological processes together with the essential feedback from spatial interactions. MPeat2D employs poroelasticity theory that couples fluid flow and solid deformation to model the influence of peat volume changes on peatland ecology and hydrology. To validate the poroelasticity formulation, the comparisons between numerical and analytical solutions of Mandel’s problems for two-dimensional test cases are conducted. The application of MPeat2D is illustrated by simulating peatland growth over 5000 years above the flat and impermeable substrate with free-draining boundaries at the edges, using constant and variable climate. In both climatic scenarios, MPeat2D produces lateral variability of water table depth, which results in the variation of vegetation composition. Furthermore, the drop of the water table at the margin increases the compaction effect, leading to a higher value of bulk density and a lower value of active porosity and hydraulic conductivity. These spatial variations obtained from MPeat2D are consistent with the field observations, suggesting plausible outputs from the proposed model. By comparing the results of MPeat2D to a one-dimensional model and a two-dimensional model without the mechanical process, the significance of mechanical-ecohydrological feedback on spatial heterogeneity, peatland shape, carbon accumulation, and resilience is highlighted.

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“…Vitousek argues that the relative simplicity of island ecosystems facilitates findings that can be applied to situations on larger landmasses. Using this approach, Dykes and Selkirk‐Bell () studied the incidence of peat slides on the Subantarctic Islands to better understand the factors causing them in Ireland. The most common form of model system research in the Subantarctics is, however, restoration ecology.…”

Section: An Example In the New Zealand Subantarctic Islandsmentioning

confidence: 99%

Our view of islands: Joining the values of science and society

Sides¹,

Davis²,

Rock³

2014

Eco Management Restoration

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Summary Both the public and the scientific perception of an island's value are important in deciding its future, with regard to the levels of access, protection and funding for research. There is a popular belief that the preservation of islands equates to the slightly idiosyncratic conservation of unique remote habitats, where the value of any island is its isolation. However, by understanding how scientists use islands, a different picture emerges; islands may be seen also as integrated, or representative fragments of the world that contribute to biodiversity and scientific theory far beyond their narrow geographical boundaries. Here, we broadly review the full scope of values science places on islands. We resolve four central perspectives by which scientists view islands, based on how islands are incorporated into their research: (i) species‐level studies; (ii) island‐level studies; (iii) islands as model systems; and (iv) islands as part of a global network. Recognising this diverse value system helps enlarge our understanding of islands and reforges their importance to the public and policy makers.

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Landslides in blanket peat on subantarctic islands: Causes, characteristics and global significance

Cited by 7 publications

References 48 publications

Sediment deposition from eroding peatlands alters headwater invertebrate biodiversity

Sediment deposition from eroding peatlands alters headwater invertebrate biodiversity

MPeat2D – A fully coupled mechanical-ecohydrological model of peatland development in two dimensions

Our view of islands: Joining the values of science and society

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