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Modelling adaptation of thermal reaction norms in fluctuating environments using adaptive dynamics
Suleiman, A. L. 2025. Modelling Adaptation of Thermal Reaction Norms in Fluctuating Environments using Adaptive Dynamics. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/a190a40f-2c81-49ca-8cb6-a6296ea6c4dc
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Stellenbosch : Stellenbosch University
2025
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| access_status_str | Open Access |
| author | Suleiman, Abdulrahaman Lawal |
| author2 | Landi, Pietro |
| author_browse | Landi, Pietro Suleiman, Abdulrahaman Lawal |
| author_facet | Landi, Pietro Suleiman, Abdulrahaman Lawal |
| author_sort | Suleiman, Abdulrahaman Lawal |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Suleiman, A. L. 2025. Modelling Adaptation of Thermal Reaction Norms in Fluctuating Environments using Adaptive Dynamics. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/a190a40f-2c81-49ca-8cb6-a6296ea6c4dc |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132413 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:44:49.127Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132413 Modelling adaptation of thermal reaction norms in fluctuating environments using adaptive dynamics Suleiman, Abdulrahaman Lawal Landi, Pietro Hui, Cang Stellenbosch University. Faculty of Science. Dept. of Applied Mathematics. Thermal adaptation -- Mathematical models Thermal reaction norms Adaptive dynamics UCTD Suleiman, A. L. 2025. Modelling Adaptation of Thermal Reaction Norms in Fluctuating Environments using Adaptive Dynamics. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/a190a40f-2c81-49ca-8cb6-a6296ea6c4dc Thesis (PhD)--Stellenbosch University, 2025. ENGLISH ABSTRACT: This study focuses on how thermal reaction norms, also known as thermal performance curves (TPCs), evolve in different thermal regimes. The thermal reaction norm is modelled using the probability distribution function of a beta distribution defined by two shape parameters: the mean and scaling parameter related to the TPC breadth. These shape parameters determine the optimal temperature and the standard deviation of the TPC. Evolutionary adaptation to varying environments can reshape the TPC by altering its position (through horizontal shifts in optimal temperatures) and the breadth (simultaneous vertical and horizontal shift), though physiological constraints can impose a generalist-specialist trade-off between the TPC height and breadth. TPCs are commonly used to capture the response of species to climate change. Evolutionary adaptation of these curves to varying thermal regimes has been studied extensively using empirical and theoretical approaches. However, theoretical studies on the adaptive evolution of the TPC shape under thermal regime changes remain scarce. To bridge this gap, I used the adaptive dynamics (AD) framework to develop Lotka-Volterra and Ricker competition models, investigating how intraspecific competition among ectotherm individuals drives TPC adaptation under varying thermal regimes. In the periodic thermal regime, temperature is modelled using a sinusoidal function, while in the stochastic environment, it is modelled using different noise structures (white and colored). The intrinsic growth rate and carrying capacity in each model are assumed to depend on temperature, while the strength of competition among individuals is proportional to the ratio of their TPCs at the current environmental temperature. Results show that in the constant temperature environment, TPC adaptation leads to local adaptation of complete thermal specialization while in periodic environments, broader TPC evolved indicating thermal generalization. Bimodal (U-shaped) TPCs also emerged, indicating adaptation to lower and upper temperature extremes and possible character divergence. In uncorrelated stochastic environments (white noise), adaptation results in moderately narrow TPCs (specialization) and J-shaped TPCs (specialization towards lower temperatures). In correlated stochastic environments (colored noise), adaptation leads to similar narrow and broad TPCs as well as J-shaped TPCs, as observed in white noise environments. Additionally, bimodal (U-shaped) TPCs emerged. This study shows that thermal adaptation in fluctuating environments results in specialization (narrower TPCs), generalization (broader TPCs), and adaptation to lower temperatures (J-shaped TPCs) or both lower and upper temperature extremes (bimodal/U-shaped TPCs). This research provides a theoretical foundation for studying the adaptation of thermal reaction norms in fluctuating environments. AFRIKAANSE OPSOMMING: Hierdie studie fokus op hoe termiese reaksienorme, ook bekend as termiese prestasiekrommes (TPK's), in verskillende termiese omgewings ontwikkel. Die termiese reaksienorm word gemodelleer deur gebruik te maak van die waarskynlikheidsverdelingsfunksie van 'n betaverdeling wat deur twee vormparameters gedefinieer word: die gemiddelde en skaalparameter wat verband hou met die TPK-breedte. Hierdie vormparameters bepaal die optimale temperatuur en standaardafwyking van die TPK. Evolusionêre aanpassings by verskillende omgewings kan die TPK vervorm deur sy posisie te verander deur ʼn horisontale verskuiwing (vir optimale temperatuur) en die breedte (gelyktydige vertikale en horisontale uitspreiding), alhoewel fisiologiese beperkings 'n algemene praktisyn-spesialisafweging tussen die TPKhoogte en -breedte kan veroorsaak. TPK's word algemeen gebruik om die reaksie van spesies op klimaatsverandering vas te stel. Deur empiriese en teoretiese benaderings te gebruik, is die evolusionêre aanpassing van hierdie krommes aan verskillende termiese omgewings omvattend bestudeer. Teoretiese studies oor die aanpasbaarheidsevolusie van die TPK-vorm onder termiese omgewingsveranderinge bly egter skaars. Om hierdie gaping te oorbrug, het ek die aanpasbaarheidsdinamika (AD) raamwerk gebruik om Lotka-Volterra en Ricker kompetisiemodelle te ontwikkel, en het ondersoek hoedat die intraspesifieke mededinging tussen ektoterm individue die TPK-aanpassing onder verskillende termiese omgewings/omstandighede aandryf. In die periodieke termiese omgewings word temperatuur gemodelleer deur 'n sinusvormige funksie te gebruik, terwyl dit in die stogastiese omgewing gemodelleer word deur verskillende geraasstrukture (wit en gekleurd) te gebruik. Daar word aanvaar dat die intrinsieke groeitempo en drakrag in elke model van temperatuur afhang, terwyl die sterkte van mededinging tussen individue eweredig is aan die verhouding van hul TPK's teen die huidige omgewingstemperatuur. Resultate toon dat in die konstante temperatuur omgewing, Aanpassing van die TPK lei tot lokale aanpassing van volledige termiese spesialisering terwyl in periodieke omgewings ʼn breër (meer uitgespreide) TPK ontwikkel het wat termiese veralgemening aandui. Bimodale (U-vormige) TPK's het ook voorgekom, wat aanpassing tot laer en hoër temperatuur-uiterstes en moontlike karakterdivergensie aandui. In ongekorreleerde stogastiese omgewings (wit geraas) lei aanpassing tot matige smal TPK's (spesialisering) en J-vormige TPK's (spesialisering tot laer temperature). In gekorreleerde stogastiese omgewings (gekleurde geraas), lei aanpassing tot soortgelyke smal en breë TPK's sowel as J-vormige TPK's, soos waargeneem in wit geraas omgewings. Daarbenewens het bimodale (U-vormige) TPK's na vore gekom. Hierdie studie toon dat termiese aanpassing in fluktuerende omgewings lei to spesialisering (smal TPK's), veralgemening (breër TPK’s) en aanpassing by laer temperature (J-vormige TPK's) of beide laer en hoër temperatuur uiterstes (bimodale/U-vormige TPK's). Hierdie navorsing verskaf 'n teoretiese grondslag vir die bestudering van die aanpassing van termiese reaksienorme in fluktuerende omgewings. Doctoral 2025-06-06T08:44:37Z 2025-06-06T08:44:37Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132413 en Stellenbosch University xvii, 121 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Thermal adaptation -- Mathematical models Thermal reaction norms Adaptive dynamics UCTD Suleiman, Abdulrahaman Lawal Modelling adaptation of thermal reaction norms in fluctuating environments using adaptive dynamics |
| title | Modelling adaptation of thermal reaction norms in fluctuating environments using adaptive dynamics |
| title_full | Modelling adaptation of thermal reaction norms in fluctuating environments using adaptive dynamics |
| title_fullStr | Modelling adaptation of thermal reaction norms in fluctuating environments using adaptive dynamics |
| title_full_unstemmed | Modelling adaptation of thermal reaction norms in fluctuating environments using adaptive dynamics |
| title_short | Modelling adaptation of thermal reaction norms in fluctuating environments using adaptive dynamics |
| title_sort | modelling adaptation of thermal reaction norms in fluctuating environments using adaptive dynamics |
| topic | Thermal adaptation -- Mathematical models Thermal reaction norms Adaptive dynamics UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132413 |
| work_keys_str_mv | AT suleimanabdulrahamanlawal modellingadaptationofthermalreactionnormsinfluctuatingenvironmentsusingadaptivedynamics |