ΣPhD Symposium

Speaker: Cristina Linares (University of Barcelona, Catalonia, Spain)

Title: Understanding the functioning of benthic ecosystems in a warmer ocean: from macroecology to community and population ecology perspectives

Abstract: In the last decades, an increase in biodiversity loss and shifts in the structure and functioning of marine ecosystems have been documented due to human stressors, such as pollution, overexploitation of natural resources, habitat destruction, the introduction of exotic species and climate change, compromising the services and benefits that they provide. From individual species to entire ecosystems, local and global stressors are affecting the ocean at all levels of biological organization. However,  most studies have traditionally dealt with responses at single, and typically simple, levels of biological organization hindering our understanding of how global change affects marine ecosystems as a whole. In this talk, I discuss the need for interdisciplinary approaches combining macroecological with population and community ecology studies, long-term data series and mathematical modelling. These multiple approaches will improve our understanding of how marine benthic ecosystems, and concretely key habitat-forming species displaying different life-history traits, respond across different spatial scales and depth gradients. Integrating different levels of organizations and principles of ecological theory will help to promote more efficient conservation and restoration measures in a context of rapid environmental changes.

Speaker: Jason Matthiopoulos, (University of Glasgow, Scotland, UK)

Title: Defining, estimating and understanding the fundamental niches of complex animals in heterogeneous environments

Abstract: During the past century, the fundamental niche, the complete set of environments that allow an individual, population, or species to persist, has shaped ecological thinking. It is a crucial concept connecting population dynamics, spatial ecology and evolutionary theory, and a prerequisite for predictive ecological models at a time of rapid environmental change. Yet, its properties have eluded quantification, particularly for mobile, cognitively complex organisms. These difficulties are mainly a result of the separation between niche theory and field data, and the dichotomy between environmental and geographical spaces. Here, I combine recent mathematical and statistical results linking habitats to population growth, to achieve a quantitative and intuitive understanding of the fundamental niches of animals. I trace the development of niche ideas from the early steps of ecology to their use in modern statistical and conservation practice. I examine, in particular, how animal mobility and behaviour may blur the division between geographical and environmental space. I discuss how the fundamental models of population and spatial ecology lead to a concise mathematical equation for the fundamental niche of animals and demonstrate how fitness parameters can be understood and directly estimated by fitting this model simultaneously to field data on population growth and spatial distributions. I illustrate these concepts and methods using both simulation and real animals and, in this way, confirm ideas that had been anticipated in the historical niche literature. Specifically, within traditionally defined environmental spaces, habitat heterogeneity and behavioural plasticity make the fundamental niche more complex and malleable than was historically envisaged. However, once examined in higher-dimensional spaces, the niche is more predictable, than recently suspected. This re-evaluation quantifies how organisms might buffer themselves from change by bending the boundaries of viable environmental space, and offers a framework for designing optimal habitat interventions to protect biodiversity or obstruct invasive species. It therefore promotes the fundamental niche as a key theoretical tool for understanding animal responses to changing environments and a central tool for environmental management. To this end, ecological mechanism (dispersal, density dependence, community effects and individual variation), integrated inference, and ecosystem optimization are the key future areas of development.

Speaker: Alejandro Martínez-Abraín (Universidade da Coruña, Galicia, Spain)

Title: The current state of the biosphere: optimism or doom and gloom?

Abstract: Our 21^st century society is loaded with a deep negative view regarding the human-rest-of-the-biosphere relationship. This is puzzling because when environmental facts are analyzed in depth we find that current trends foresee a good future for the Earth ecosystems. I will discuss in my talk a number of topics including current human population growth, rates of Amazonian deforestation, rates of shrub and tree encroachment in Europe and the comeback of formerly threatened predators in Europe and North America. I present the current warming trend of the Earth atmosphere from a paleo-climatological view point and discuss the differential effects of warming on terrestrial and marine ecosystems. I will also talk about the insect crisis, the prospects of air and water pollution and of species loss and gain. I will try to challenge your views regarding all these topics, and will be happy to answer all your questions.