Carregant...
Tipus de document
TesiVersió
Versió publicadaData de publicació
Si us plau utilitzeu sempre aquest identificador per citar o enllaçar aquest document: https://hdl.handle.net/2445/216127
Species interactions, ecosystem functioning and the resilience of marine vegetated ecosystems in a global change era
Títol de la revista
Autors
Director/Tutor
ISSN de la revista
Títol del volum
Resum
[eng] Human domination of Earth’s Systems is transforming life at a planetary scale. A plethora of anthropogenic pressures disrupt environmental conditions, degrading ecosystem functioning and posing unprecedented threats to global biodiversity and human life support systems. In this context of global anthropogenic change, acquiring accurate ecological knowledge is crucial for identifying warning indicators and ecosystem tolerance limits. Such knowledge can inform ecosystem managers and aid in mitigating stressors at local and/or regional scales that further fuel this global change.
Marine vegetated ecosystems, including seagrass meadows and macroalgal forests, rank among the most productive habitats on Earth. They support a significant portion of the world’s biodiversity and fisheries while contributing to carbon sequestration. However, these ecosystems face severe threats from global change, which vary according to their tolerance limits and eventually shape their vulnerability against human pressures. In addition, macrophyte ecosystems often exhibit nonlinear responses to stress, including abrupt and catastrophic shifts. These inherent ecosystem properties further complicate predictions about their resistance and resilience (and, therefore, their management), making these systems excellent models for assessing the effects of global change in nature.
In this thesis, I focus on key ecological mechanisms that shape the functioning and resilience of marine macrophytes and explore their interactions with herbivores under various global-change-related stressors, such as eutrophication, overfishing, or tropicalization. Specifically, I investigate (i) seagrass responses to cope with light limitation, (ii) how species-specific attributes allow seagrasses to colonize distinct depth ranges on a global scale, (iii) the influence of abiotic and biotic factors in shaping ecological contexts and thus macrophytes vulnerability to herbivory, and (iv) how mixed-shoaling behaviours between range-extending and native herbivorous fishes influence their specific foraging activity and efficiency in the tropicalized environments of the eastern Mediterranean Sea.
20
The first results in this thesis emphasize the importance of physiological photo-acclimatization for macrophyte resistance and recovery (i.e., resilience) against light limitation. While such acclimatization can reduce minimum light requirements, only self-facilitation mechanisms alleviating mortality rates lead to bistability in seagrass meadows. Secondly, the species-specific ability of seagrasses to persist across depth ranges depends on their acclimatization potential in key physiological, morphological, and structural traits, regardless of species size or functional group. Third, plant-herbivore interactions in marine macrophyte ecosystems are mediated by an array of endogenous and exogenous factors of biotic and abiotic nature. These factors include the identity of both biotic interactors, herbivore size, or the fear imposed by predators, and the nutrients, temperature, and depth conditions. Lastly, the global redistribution of tropical and warm-adapted species results in novel species interactions in temperate environments. In the eastern Mediterranean, range-extending herbivorous fish species engaged more in mixed-species shoaling behaviours, forming larger groups and increasing their foraging activity and efficiency. In contrast, native Mediterranean herbivores do not exhibit that ability to shoal in mixed-species groups nor obtain such foraging benefits.
Overall, this thesis focuses on species features and ecological contexts to understand how species and marine vegetated ecosystems cope and respond to stressors of human origin. This thesis highlights (i) the role of species-specific acclimatization capacities of marine macrophytes in shaping their vulnerability to anthropogenic impacts degrading water quality, especially at their deep limits, (ii) the highly species-specific and context-specific vulnerability of macrophyte communities to herbivory, and (iii) that the mixed-species shoaling behaviour of range-extending species with temperate species results in a mechanism that partially explains the enormous herbivory pressures experienced by macrophytes in tropicalized reefs. Consequently, management at local scales is critical for maintaining healthy and resilient macrophyte ecosystems in the face of global anthropogenic pressures.
Descripció
Matèries (anglès)
Citació
Citació
MINGUITO FRUTOS, Mario. Species interactions, ecosystem functioning and the resilience of marine vegetated ecosystems in a global change era. [consulta: 4 de desembre de 2025]. [Disponible a: https://hdl.handle.net/2445/216127]