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In this thesis, I combined field, common-garden and greenhouse experiments to examine the ecological and evolutionary consequences of plant-herbivore interactions in the perennial herb Lythrum salicaria. More specifically I examined (1) whether resistance and tolerance to damage from herbivores vary with latitude and are positively related to the intensity of herbivory in natural populations, (2) whether effects of herbivory on plant fitness vary with latitude, (3) whether populations are locally adapted and whether herbivory influences the relative fitness of populations, and (4) whether the intensity and effects of insect herbivory on reproductive output vary locally along a disturbance gradient and are associated with differences in plant resistance. A common-garden and a greenhouse experiment demonstrated that plant resistance decreased whereas plant tolerance increased with latitude of origin among populations sampled along a latitudinal gradient in Sweden. Oviposition and feeding preference in the greenhouse and leaf damage in the common-garden experiment were negatively related to natural damage in the source populations. Experimental removal of insect herbivores in three populations sampled along the latitudinal gradient demonstrated that intensity of herbivory and its effects on plant fitness decreased towards the north. A reciprocal transplant experiment among the same three populations showed that herbivory affected the relative fitness of the three populations, but did not detect any evidence of local adaptation. Instead the southernmost population had the highest relative fitness at all three sites. A herbivore-removal experiment conducted in nine populations in an archipelago in northern Sweden demonstrated that insect herbivory strongly influenced among-population variation in reproductive output. However, variation in resistance was not related to differences in intensity of herbivory at this spatial scale. Taken together, the results demonstrate that resistance and tolerance to herbivory vary with latitude but in opposite directions, that intensity of herbivory is a major determinant of flowering and seed output, and that the strength of herbivore-mediated selection varies among populations in Lythrum salicaria. They further indicate that both physical disturbance regime and latitudinal variation in abiotic conditions may strongly influence the performance and abundance of perennial herbs because of their effects on interactions with specialized herbivores.

The Florida Reef Tract (FRT) extends from the tropical Caribbean up the southeast coast of Florida into a temperate environment where tropical reef assemblages diminish with increasing latitude. This study used data from a three-year comprehensive fishery-independent survey to quantify reef fish spatial distribution along the Southeast FRT and define where the assemblage shifts from tropical to temperate. A total of 1,676 reef fish visual census samples were conducted to assess the populations on a stratified-random selection of sites of marine hardbottom habitats between the Miami River and St. Lucie inlet. Multivariate analyses were used to investigate differences in assemblages among sites. Depth (m), general habitat (reef or hardbottom), and slope (high or low) strata were examined to explain the dissimilarities between assemblages. A general trend of cold-tolerant temperate fish dominated the northern assemblages and more tropical species dominated further south. Seven reef fish assemblage biogeographic regions were determined. In shallow habitats the data clustered in three spatial regions: One south of Hillsboro inlet, one in Northern Palm Beach south of Lake Worth inlet, and one north of Lake Worth inlet. The assemblage in deep habitats mainly split in close proximity to the Bahamas Fracture Zone south of Lake Worth Inlet. The presence of reef habitat aided in splitting the southern assemblage regions from the northern all-hardbottom assemblage regions in both the shallow and deep habitats. Substrate relief was significantly correlated with the differences in the northernmost deep assemblages but did not appear to affect the remainder of the shallow and deep assemblages. This bioregional study creates a baseline assessment of reef fish assemblages of the Southeast FRT for future analyses.

The aim of this work was to evaluate the limits of ranges of European land snail species along the north-south gradient. To work out the document it was necessary to prepare the set of digitalized maps, that enabled to create the database of ranges of the individual land snails species. Based on obtained data I tried to identify places where the northern and southern borders of species ranges are the most frequent. The landsnails' ranges are affected not only by particular life requirements of the individual species (potential limits), but also by other conditions, especially climatic, geographical and historical (truncated limits). In this work I focused on their differentiation. Above mentioned process also enabled me to track the north- south changes in species richness of the landsnails taking into consideration the truncated and potential limits. The most important natural barriers constraining that numerous of species cannot naturally widespread from the south to the north are the Scandinavian Mountains, the Alpes and the Carpathians and suprisingly also southern borders of german and polish lowlands. On the other hand, spreading of the species form the north to the south is limited only by the Alpes. I also tried to distinguish the group of species whose ranges are not influenced by these...

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En la presente tesis se muestrearon ríos sobre los 2000 msnm (ríos altoandinos tropicales) que se distribuyen en la amplia región de los Andes del Norte (Ecuador) y los Andes Centrales (Perú) en Sudamérica. El muestreo de las 123 localidades se realizó en época seca, las cuales se seleccionaron tomando en cuenta su grado de alteración, que van desde sin o poca alteración (referencia) hasta muy alterados. En una primera instancia se analizaron las carácteristicas fisicoquímicas e hidromorfológicas de los ríos, las cuales mostraron una alta influencia de la altitud. Se registraron reducciones en la temperatura y oxígeno a medida que la altitud se incrementaba, por otra parte las diferencias en la heterogeneidad de los hábitats, así como la calidad del bosque de ribera fueron dos factores con un alta importancia al momento de caracterizar los ríos altoandinos. Se econtraron diferencias en la mineralización en los diferentes dominios morfotectónicos, siendo más elevados los valores de conductividad en las zonas del sur, debido a la geomorfología propia de cada zona. La comunidad bentónica mostro estar altamente influenciada por la altitud y la latitud. La altitud mostró intervenir positiva o negativamente en la abundancia y frecuencia de algunos géneros como Hyalella, Podonomopsis, Claudioperla, Anomalopsyche, Paltostoma, Rheotanytarsus, Camelobaetidius, etc. Por su parte, la latitud reveló la tendencia de algunos taxa a disminuir o aumentar su abundancia y frecuencia, tal es el caso de Anacroneuria, Camelobaetidius, Anchytarsus, Hagenulopsis, Claudioperla, Austrelmis, Smicridea, etc. Por otra parte y como punto novedoso para el conicimiento de la zona de estudio, se analizó a la familia Chironomidae a nivel de género, hecho importante para el conocimiento taxónomico de la familia en ríos tropicales de los Andes sobre los 2000 msnm, ya que no hay trabajos a este nivel taxonómico en la zona altoandina. La familia Chironomidae mostro patrones similares a los de la comunidad bentónica en general, sindo los factores relacionados con la altitud (oxígeno y temperatura) lo que determinan en gran medida su distrbución, sin embargo, al igua que el resto de la comunidad la heterogenidad de hábitats mostraron ser de suma importancia para la familia de los quironómidos. Además, la litografía y la biogeografía fueron dos factores que determinan la composición de esta familia. Con esta visión general, se analizaron los patrones de biodiversidad de estos ríos, donde se determinó que la comunidad bentónica altoandina tiene una amplia variabilidad en la diversidad local mientras que si analizamos la diversidad Gamma hay una tendencia a disminuir tanto a medida que la altitud y la latitud aumentan. Por su parte se evidenció cambios en la composición de la comunidad, la cual fue evidente también en ambos gradientes, sin embargo debido a la amplia heterogeneidad ambiental fue necesario analizar la reposición de especies a diferentes escalas de agrupación ya que sin esta corrección los cambios ambientales locales no permiten visualizar los patrones existentes en la comunidad, indicandonos la importancia de los factores locales en la biodiversidad regional. Finalmente, y con la recopilación de la estructura, composición y distribución de la fauna béntica, así como de la variabilidad ambiental tanto natural como antropogénica, se desarrolló un índice multimétrico que nos permite evaluar la calidad ecológica de los ríos altoandinos aplicable a una zona geográfica amplia. Los análisis previos al desarrollo del índice multimétrico demostraron que la variabilidad de la zona alta (localidades de páramo y puna) y la zona baja (localidades de bosque montano) era diferente. Posteriormente usando a las comunidades de macroinvertebrados acuáticos de las localidades de referencia se determinaron a dichas zonas como tipologías diferentes, las cuales se usaron para desarrollar el IMEERA-B (Bosque) y el IMEERA-P (Páramos y Punas). En nuestro estudio en la zona baja el gradiente de presión está determinado por la contaminación orgánica y la degradación hidromorfológica, y en la zona alta el gradiente está influenciado por la contaminación orgánica y la heterogeneidad del hábitat. Finalmente, se determinaron 6 métricas para IMEERA-B que evalúan la riqueza, el hábito y la tolerancia/intolerancia, y para el IMEERA-P se determinaron 4 métricas que evalúan la riqueza y la tolerancia/intolerancia. / STRUCTURE AND COMPOSITION OF AQUATIC MACROINVERTEBRATES COMMUNITIES IN HIGHLAND ANDEAN RIVERS OF ECUADOR AND PERU. DESIGN OF A MEASURE OF WATER QUALITY WITH MULTIMETRIC INDEXES In this thesis we sampled Highland Andean Rivers above 2000 m a.s.l. (tropical andean highland rivers) which are distributed in a wide geographical region of the North Andes (Ecuador) and Central Andes (Peru) in South America. In total 123 sites were sampled in dry season, which were selected taking into account the anthropogenic influence gradient, ranging from no alteration, little alteration (i.e., reference) to highly altered. The physico-chemical caracteristics of rivers showed a high altitud influence. We recorded a decrease in both temperature and oxygen as altitude increases. Habitat heterogeneity and the riverine forest quality were identified as determinant enviromental characteristics regarding the andean higland rivers studied. The mineralization show differences between the morphotectonics groups, while were the conductivity was higher at the south, depending on the geomorphology of each zone. The sampled macroinvertebrate assemblages were influenced by both latitudinal and altitudinal gradients. In detail, assemblages showed different gradient responses (positive or negative), depending of the organism and its requirements. The patterns of abundance and richness are probably determined by the environmental variability observed, and described by the temperature, oxygen, habitat heterogeneity and the presence, and absence of riverine forest. The family Chironomidae, as we expected, showed different responses depending of the genus, while the composition of the family was determined mainly by temperature, oxygen, lithography. and biogeography. We also studied the biodiversity patterns of Highland Andean Rivers rivers. The benthic community assemblage showed a high variability at local diversity (alpha diversity), while the gamma diversity decreased in both latitude and altitude gradients. Moreover, the community presented some discontinuities in the beta diversity. Regarding latitudinal gradient, the composition of assemblage changed in each morphological group, while altitude changes were described by vegetation types (mountain forest or páramo-puna) or presence or absence of riverine forest. Finally, using the aquatic macroinvertebrate communities of the reference sites, two different zones were identified as distinct from each other: from 2000 to 3500 m a.s.l and those sites at altitudes higher than 3500 m a.sl.. For such reasons two versions of a multi-metric index - the IMEERA index - were developed. The IMEERA B index includes six metrics evaluating richness, habit and tolerance/intolerance. The IMEERA P index was calculated using four metrics evaluating richness and tolerance/intolerance. Results showed that in lower altitudes (Bosque river type, IMEERA-B index), the pressure gradient was driven by the organic pollution and the hydromorphological degradation, while in higher altitudes (Páramo and Puna river types; IMEERA-P river type), the gradient was driven by the organic pollution and the habitat heterogeneity.

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Each species has specific adaptations to its environment, and since environmental parameters reveal geographic trends, it is reasonable to expect the existence of geographic trends in species characteristics as well. The aim of this study has been to evaluate the effect of environmental conditions on geographic variability of functional traits of European birds. I have analysed the effect of temperature, precipitation, productivity, altitude and habitat type (forest, open habitats, bush, settlements, wetlands) on clutch size, number of clutches per breeding season, egg size, incubation length, age of maturity, body mass, wing, tail, bill and tarsus length. I have used data from the European breeding bird atlas, so that I have calculated mean values of all the traits for quadrats 50x50 km, and then related them to environmental characteristics using OLS and GLS. Clutch size increases with temperature, whereas the number of clutches decreases with it, indicating possible trade-off between clutch size and the number of clutches, whose result is determined by the length of breeding season. Egg size decreases with temperature, possibly due to higher survival of large eggs (and consequently juveniles) in cold regions. Incubation length increases with both temperature and environmental productivity,...

Les performances du végétal et des arthropodes dont il constitue le microhabitat dépendent des températures de surface foliaire. Celles-ci peuvent dévier fortement de la température de l’air et présenter des niveaux d’hétérogénéité différents selon l'échelle spatiale considérée. La feuille atténue les températures extrêmes en rapprochant son amplitude de variation journalière de celle de la température de l’air. Cependant, cette réponse diminue l’hétérogénéité des températures de surface foliaire et les capacités de thermorégulation comportementale des arthropodes à l'échelle de la feuille. Les températures moyennes de surface foliaire atténuent peu le réchauffement, et déterminent localement la performance photosynthétique du végétal. De l’échelle de la feuille à celle de la canopée, les plantes montrent des réponses différentes au réchauffement. Ce type de changement d'échelle est primordial pour améliorer notre compréhension de l'impact des changements climatiques. / Plant performance and leaf-dwelling arthropods are impacted by leaf surface temperatures. Leaf surface temperatures can show important deviation from air temperature and present different levels of heterogeneity depending on the spatial scale. The leaf buffers temperature extremes by getting closer in amplitude to air temperature. However, this physiological response decreases the heterogeneity of temperatures at the leaf surface and the opportunities for arthropods to behavioraly thermoregulate in this microclimate. Mean temperatures at the leaf surface show low buffering abilities in response to warming and locally determine photosynthetic performance. From the leaf to the canopy scale, plants show different responses to warming and scaling is crucial to increase our understanding of the impact of global warming.