Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/104250
Title: Morphological structure and biodiversity in fish assemblages = Estructura morfològica i biodiversitat en comunitats de peixos
Author: Farré Foix, Marc
Director: Tuset Andújar, Víctor Manuel
Lombarte Carrera, Antoni
Palacín Cabañas, Cruz
Keywords: Morfologia animal
Peixos
Biodiversitat
Animal morphology
Fishes
Biodiversity
Issue Date: 15-Jul-2016
Publisher: Universitat de Barcelona
Abstract: [eng] The study of morphology of organisms has become a widely extended scientific discipline since the beginning of the 20th century, when the scientific community began to establish direct relationships between the anatomical characteristics of organisms and their adaptations and biological strategies. The study of morphological variability allowed determining and understanding the ecological and functional roles of species within the ecosystems where they inhabit. According to this ecomorphological current, ecologists promptly perceived that morphology of species were essential to address many aspects traditionally of their interest that were essential to understand the functioning and organization of communities, such as the resource partitioning or the habitat differentiation. Following these premises, the overall objective of this thesis was to determine and describe the morphological diversity of several fish assemblages, in order to highlight the importance of the study of the morphology of species as an alternative and complementary useful tool in biodiversity and community structure studies. To test the hypotheses and reach the purposes, several fish assemblages with different geographical, environmental, ecological and hydrological conditions were analysed: from mesopelagic fish assemblages from the Canary Islands (NE Atlantic ocean) to coastal fish assemblages along the Catalan coast or demersal fish assemblages along a wide bathymetric range along the continental shelf and slope of the Balearic Islands (NW Mediterranean Sea). The morphological analysis included the overall body shape and the shape and position of fins and sensory organs, and was performed using landmark-based geometric morphometric methods (GM). These analyses are widely used for quantifying and analysing the shape variation between structures, since they allow to describe the geometric characteristics of the structures easily, quickly and with higher level of detail; they conserve the geometric traits of objects along all the procedure and they possess a powerful associated statistical support. Besides, the application of GM also allows the computation of measures of morphological diversity. Thus, another objective of this thesis was to develop new morphological diversity indices from GM methods and describe their correlations with other biodiversity components traditionally more considered (ecological, taxonomical and functional diversity) in order to demonstrate the validity and provide and additional approach that helps to complement studies of biodiversity of fish assemblages. The morphological structures (morphospaces) and the biodiversity indices were obtained for all the analysed fish assemblages and were compared to assess the ability of the morphological methods in order to describe the structure and organization of fish communities. The results demonstrated that the computed morphological diversity indices correlated significantly with the other biodiversity components, were useful for biodiversity studies since they provide information about the functioning and structure of communities (especially when ecological or functional traits of species and ecosystems are absent or scarce, which can be very common), and in addition they yielded equivalent results when they were computed using quantitative (abundance) and qualitative (presence/absence) data. Besides, the analysis of the morphospaces of the different communities allowed to infer and understand key aspects about the functioning and organization of communities, such as the resource partitioning, the habitat differentiation or interspecific relationships such as coexistence, competence or dominance. Therefore, the general results of the present thesis reinforces and support the hypothesis that the morphology of species is a good tool addressing the ecological and functional roles of species within ecosystems, and that the assessment of the morphological variability among species contributes to better understanding the structure, organization and functioning of communities.
[cat] L’estudi de la morfologia ha esdevingut una disciplina científica amplament estesa des d’inicis del segle XX, quan es van començar a establir relacions directes entre les característiques anatòmiques dels organismes i les seves adaptacions i estratègies biològiques. L’anàlisi de la variabilitat morfologia permetia definir els rols ecològics i funcionals de les espècies dins els ecosistemes. Seguint aquestes premisses, l’objectiu principal d’aquesta tesi consistia en descriure la diversitat morfològica present en diverses comunitats de peixos teleostis amb condicions ambientals, ecològiques, hidrològiques i geogràfiques diferents, per tal de demostrar la importància de l’estudi de la morfologia com a eina vàlida i complementària en estudis de biodiversitat i d’estructura de comunitats. La caracterització morfològica de les espècies va incloure la forma general del cos així com la forma i posició de les aletes i òrgans sensorials, i va ser mesurada i analitzada mitjançant mètodes de morfometria geomètrica (GM) basats en landmarks. Aquests mètodes son comunament utilitzats per quantificar la variació en la forma entre estructures, ja que permeten descriure les característiques geomètriques del objectes detalladament de manera senzilla i ràpida i presenten un rigorós suport estadístic associat. Un altre objectiu va ser desenvolupar noves mesures de diversitat morfològica a partir de mètodes de GM i determinar la seva correlació amb altres components de la biodiversitat tradicionalment utilitzats (diversitat ecològica, taxonòmica i funcional). Els resultats van demostrar que els índexs morfològics aporten informació addicional en estudis de biodiversitat, que correlacionen significativament amb els altres components de la diversitat i que proporcionen resultats equivalents quan es calculen amb dades qualitatives i quantitatives. A més, l’anàlisi de les estructures morfològiques (morfoespais) de les comunitats va permetre investigar els rols ecològics i funcionals de les espècies, essencials per entendre aspectes que determinen el funcionament i organització de les comunitats, com la repartició de recursos, la diferenciació d’hàbitat o relacions interespecífiques com la coexistència, la competència o la dominància. Per tant, els resultats generals de la tesi reforcen la hipòtesi de que l’avaluació de la variabilitat morfològica es una eina útil que contribueix a millorar el coneixement sobre l’estructura i organització de les comunitats de peixos.
URI: http://hdl.handle.net/2445/104250
Appears in Collections:Tesis Doctorals - Facultat - Biologia

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