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Loss of Dynamic Stability in a Host-Parasitoid System is Related to the Magnitude and Temporal Scale of Trend in Environmental change. / BRETT PETERSEN

Swansea University Author: BRETT PETERSEN

Abstract

Climate change is driving changes to populations leading to biodiversity crises. Knowledge is increasing on how populations are changing with research predicting how future population dynamics may predict population dynamics. Mathematical models have been an important tool to predict how biodiversit...

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Published: Swansea University, Wales, UK 2024
Institution: Swansea University
Degree level: Master of Research
Degree name: MA by Research
Supervisor: Fowler, M., and Coste, C.
URI: https://cronfa.swan.ac.uk/Record/cronfa66251
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spelling v2 66251 2024-05-02 Loss of Dynamic Stability in a Host-Parasitoid System is Related to the Magnitude and Temporal Scale of Trend in Environmental change. 3a65173ef4c6cfa8b4c1942a65f9c34e BRETT PETERSEN BRETT PETERSEN true false 2024-05-02 Climate change is driving changes to populations leading to biodiversity crises. Knowledge is increasing on how populations are changing with research predicting how future population dynamics may predict population dynamics. Mathematical models have been an important tool to predict how biodiversity may change as the climate changes. Much research has concentrated on a ‘step change’ of the environment, but research on the effects of a gradual increase in the environmental parameters, whereby these parameters gradually increase or decrease over time, has been underexplored.To address this gap, I used a version of the Nicholson-Bailey model that has been modified to include an environmental trend, whereby, over time, the environment increases the response of the host and parasitoids intrinsic growth rate across each time step over a temporal scale, to show how this could affect population dynamics within a discrete-time host-parasitoid system and how this differs to a constant environment. I further change the magnitude and temporal scale of the trend of the environment to establish their effects on population dynamics and try to analyse the dynamics.The constant environment became unstable after an initial transient phase, when the environmental effect on the system caused the host population growth rate to reach 115% of the current population size, showing cyclic/chaotic dynamics. The trend in the environment contrasted this by almost always having stability after the initial transient phase, sometimes becoming cyclic/chaotic at a certain environmental value within the trend when population growth rate became higher than 115% of the current population size. At smaller speeds of environmental change, the population started oscillating at lower environmental parameter values than for faster speeds. This was dependent on an increase in temporal scale, causing rate of increase from one environmental value to the next to become smaller, allowing for populations to track the environmental change and shift from stability to instability at an earlier stage, whereas larger rates of increase at smaller temporal scales rather abruptly shifted from stability to sudden amplified instability.This research emphasises the need to study the effects of a trend in the environment with more intricacy and detail, to predict the future of population dynamics under different climate change scenarios. E-Thesis Swansea University, Wales, UK Trend in environment, host-parasitoid model, climate change, stability-instability 8 4 2024 2024-04-08 A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information. COLLEGE NANME COLLEGE CODE Swansea University Fowler, M., and Coste, C. Master of Research MA by Research 2024-07-04T10:47:06.0271933 2024-05-02T17:14:22.4589693 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Biosciences BRETT PETERSEN 1 66251__30810__e631b23058ea4cd58e7549af2526e3cd.pdf 2024_Petersen_B.final.66251.pdf 2024-07-04T10:43:54.3843509 Output 2997204 application/pdf E-Thesis true Copyright: The Author, Brett Peterson, 2023 true eng
title Loss of Dynamic Stability in a Host-Parasitoid System is Related to the Magnitude and Temporal Scale of Trend in Environmental change.
spellingShingle Loss of Dynamic Stability in a Host-Parasitoid System is Related to the Magnitude and Temporal Scale of Trend in Environmental change.
BRETT PETERSEN
title_short Loss of Dynamic Stability in a Host-Parasitoid System is Related to the Magnitude and Temporal Scale of Trend in Environmental change.
title_full Loss of Dynamic Stability in a Host-Parasitoid System is Related to the Magnitude and Temporal Scale of Trend in Environmental change.
title_fullStr Loss of Dynamic Stability in a Host-Parasitoid System is Related to the Magnitude and Temporal Scale of Trend in Environmental change.
title_full_unstemmed Loss of Dynamic Stability in a Host-Parasitoid System is Related to the Magnitude and Temporal Scale of Trend in Environmental change.
title_sort Loss of Dynamic Stability in a Host-Parasitoid System is Related to the Magnitude and Temporal Scale of Trend in Environmental change.
author_id_str_mv 3a65173ef4c6cfa8b4c1942a65f9c34e
author_id_fullname_str_mv 3a65173ef4c6cfa8b4c1942a65f9c34e_***_BRETT PETERSEN
author BRETT PETERSEN
author2 BRETT PETERSEN
format E-Thesis
publishDate 2024
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Biosciences{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Biosciences
document_store_str 1
active_str 0
description Climate change is driving changes to populations leading to biodiversity crises. Knowledge is increasing on how populations are changing with research predicting how future population dynamics may predict population dynamics. Mathematical models have been an important tool to predict how biodiversity may change as the climate changes. Much research has concentrated on a ‘step change’ of the environment, but research on the effects of a gradual increase in the environmental parameters, whereby these parameters gradually increase or decrease over time, has been underexplored.To address this gap, I used a version of the Nicholson-Bailey model that has been modified to include an environmental trend, whereby, over time, the environment increases the response of the host and parasitoids intrinsic growth rate across each time step over a temporal scale, to show how this could affect population dynamics within a discrete-time host-parasitoid system and how this differs to a constant environment. I further change the magnitude and temporal scale of the trend of the environment to establish their effects on population dynamics and try to analyse the dynamics.The constant environment became unstable after an initial transient phase, when the environmental effect on the system caused the host population growth rate to reach 115% of the current population size, showing cyclic/chaotic dynamics. The trend in the environment contrasted this by almost always having stability after the initial transient phase, sometimes becoming cyclic/chaotic at a certain environmental value within the trend when population growth rate became higher than 115% of the current population size. At smaller speeds of environmental change, the population started oscillating at lower environmental parameter values than for faster speeds. This was dependent on an increase in temporal scale, causing rate of increase from one environmental value to the next to become smaller, allowing for populations to track the environmental change and shift from stability to instability at an earlier stage, whereas larger rates of increase at smaller temporal scales rather abruptly shifted from stability to sudden amplified instability.This research emphasises the need to study the effects of a trend in the environment with more intricacy and detail, to predict the future of population dynamics under different climate change scenarios.
published_date 2024-04-08T10:47:05Z
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score 11.024532

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