Aquesta tesi examina els mecanismes ecològics i evolutius que mantenen els gradients de riquesa específica en ocells. S'examinen en primer lloc el patrons de diversitat de l'avifauna de Nord Amèrica. (capitol 1). Tot seguit es testen mecanismes a escala regional, tot estudiant el cas de l'avifauna de Catalunya (capitols 2 i 3). Finalment, es testen diferents mecanismes que regulen la diversitat a escala local en una comunitat d'ocells frugívors al Parc nacional de Doñana. El capitol 6 integra tots els anteriors i els relaciona tot fent una revisió bibliogràfica en profunditat.Paraules clau: biodiversitat, ocells, adaptació, filogènia, switching behaviour, xarxes d'interacció, Nord Amèrica, Catalunya, Doñana, gradients altitudinals, productivitat. / Species richness gradients have been analyzed during many decades and they have progressively emerged as a central topic in community ecology (Darwin 1859, Wallace 1878, Willis 1922, Dobzhansky 1950, Fisher 1960, Hillebrand 2004, Riclkefs 2004, Mittelbach et al. 2007, among others). Historically, species richness gradients have been analyzed from two main points of view: the ecological and the evolutionary perspective (Ricklefs 2004, 2006b). The ecological perspective assumes that populations are evolutionarily fixed and studies species richness gradients as the result of regional colonization and extinction processes, and ecological interactions (MacArthur and Wilson 1967b, Scheiner and Willig 2005). Contrarily, the evolutionary approach states that species richness gradients are the result of geographic differences in the long-term evolutionary processes of speciation and lineage extinction (Rohde 1978, 1992, Mittelbach et al. 2007). For instance, according to the evolutionary view, tropical regions achieve higher species numbers due to increased diversification rates in low latitude areas (i.e. increased speciation and/or reduced extinction rates). Interestingly enough, recent empirical evidence derived from phylogenetic studies suggests that bird diversification rates are effectively higher in the tropics thus providing empirical support for the evolutionary view (Cardillo 1999, Cardillo et al. 2005, Golberg et al. 2005, Ricklefs 2006a, Jablonski et al. 2006, Weir and Schluter 2007). In contrast with the evolutionary approach, the ecological approach assumes that populations are evolutionary stable units and focus on the effect of regional colonization-extinction dynamics, local conditions and local interactions in determining species richness gradients (Hutchinson 1959, MacArthur and Wilson 1963, 1967ab, MacArthur and Levins 1967, May 1975, Riclkefs 2006b). The ecological approach highlights that species richness gradients can be generated by ecological mechanisms independently of the evolutionary processes of speciation and lineage extinction that conform the regional pool of available species. For instance, an environmental gradient can cause a species richness gradient by limiting the number of successful colonizations in environmentally severe localities without the participation of any speciation process in the regional pool (Wright 1983, Hanski 1997, Boulinier et al. 1998).These two contrasting and complementary views, the evolutionary and ecological approaches, are progressively being merged in a unified framework (Ricklefs 2006b, Johnson and Stinchcombe 2007). For instance, Johnson and Stinchcombe have recently proposed that two general hypotheses (H1, H2) are underlying a new synthesis between community ecology and evolutionary biology. On one hand (H1), evolutionary processes explain present-day community patterns and the ecological dynamics of species interactions. For instance, extinction and colonization processes that generate species richness gradients might be shaped by species' adaptations, history and phylogenetic relationships (Wiens and Donoghue 2004, Wiens and Graham 2005, Kraft et al. 2007). On the other hand (H2), Johnson and Stinchcombe highlighted that both species interactions and community context strongly influence the direction, rate and outcome of present-day evolutionary processes (Benkman 1999, Thompson 2005). Overall, the emerging synthesis of community ecology and evolutionary ecology highlights that ecological and evolutionary views are profoundly interlinked. Here we applied an evolutionary and ecological synthetic perspective to the study of the generation and maintenance of species richness in bird communities (Johnson and Stinchcombe 2007). As a first preliminary step, we examined geographical patterns of bird species richness in North America in several functional groups and the associated environmental correlates at the continental scale (Chapter 1). Our results showed that global large-scale patterns of avian diversity in temperate regions were best viewed as the overlayed response of distinct species groups to diverse ecological factors. These results strongly suggested the convenience of choosing specific functional groups in order to examine specific macroecological evolutionary and ecological hypotheses. Consequently, in Chapter 2, we next chose forest birds as a study group for the analysis of macroecological patterns, because they are the largest group in Nearctic and Palaeoarctic regions among terrestrial birds, and hold strong species-energy relationships (Mönkkönnen et al. 2006). Regional data with colonization and extinction estimates for forest birds were available in Catalonia along an altitudinal gradient (Estrada et al. 2004) providing an exceptional dataset to study the ecological and evolutionary processes behind species richness gradients (Chapters 2 and 3). We examined the altitudinal species richness gradient in Catalonia from an evolutionary and ecological synthetic perspective. First, the role of evolutionary processes in the gradient was assessed studying changes in community phylogenetic structure along the altitudinal gradient. Secondly, the role of ecological processes was examined by studying colonization and extinction dynamics at an ecological time-scale (20 years). These analyses allowed us to examine the role of phylogeny, colonizations, extinctions, community size, productivity, habitat availability, and dispersal limitation in generating bird species richness gradients in Catalonia. However, due to the coarse structure of macroecological data used, the role of local species interactions in such processes remained yet obscure and elusive.Understanding the role of species interactions in the processes of coexistence and diversification of bird communities thus remained as a big challenge. Since long ago, ecological interactions have been hypothesized to play a role in the maintenance of diversity (Hutchinson 1959, MacArthur and Levins 1967, McPeek 1997, Mittelbach et al. 2007). Therefore, the quantitative study of species interactions was expected to provide insights on the processes that ultimately generate species richness in bird communities (Cattin et al. 2006, Rezende et al. 2007). However, data on species interactions is usually available only for specific local communities. Therefore, a macroecological approach is precluded because the bulk of the studies of community interaction networks are carried out at local scales. Accordingly, we examined the role of species interactions in the generation of species richness in a local Mediterranian bird community for which interaction good-quality data was available (Chapters 4 and 5) (Jordano 1984, 1987). We addressed the two general hypotheses delineated by Johnson and Stinchcombe (2007). First, in chapter 4, we analyzed if evolutionary processes causally affect present-day community interaction patterns and the dynamics of species interactions (H1). Secondly, in chapter five, we assessed if species interactions and community context might influence the direction, rate and outcome of present-day diversification processes that ultimately generate species richness (H2). Overall, our results provide strong support for the two hypotheses examined, thus highlighting the idea that evolutionary and ecological processes are effectively profoundly interlinked. On one hand, we show that long-term evolutionary processes effectively modulate present-day community interaction patterns and dynamics (Webb et al. 2002, Cavender-Bares and Wilczek 2003, Johnson and Stinchcombe 2007, Chapter 4). Likewise, we demonstrate that community context can potentially shape bird morphological diversification processes and drive speciation (Thompson 2005, Abrams 2006, Johnson and Stinchcombe 2007, Chapter 5). Overall, Chapters 4 and 5 provide some new empirical and theoretical insights dealing with the processes that generate and maintain local bird diversity from an integrated evolutionary and ecological perspective.

Restoration of streams that were formerly channelized for timber-floating has become increasingly common. Generally, this restoration returns boulders from riparian zones to streams, leading to wider, more heterogeneous channels with slower flows. The primary goal is to enhance fish populations, but riparian vegetation is also expected to be favoured. However, increases in floristic diversity have not been observed and reasons for this slow response are still unknown. One possible explanation might be the lack of colonist pools. I therefore investigated how surrounding plant compositions influence riparian recovery. The vascular plant flora was identified in riparian sites and in adjacent upstream riparian and upland sites. Four reach types were included: unchannelized, channelized, restored and demonstration restored. Species richness and floristic similarities among types of sites and reaches were compared. Correlations with upland and upstream channel slopes were made and the importance of variation in seed floating ability was tested. The results show that unchannelized reaches were floristically similar to their adjacent upstream riparian and upland sites, whereas channelized reaches showed more different floras. Restoration created a somewhat more homogeneous flora among the three site types and demonstration restored reaches were most similar to upstream sites. Soil moisture conditions (i.e. wetland vs. forest) in the uplands had stronger impacts on species similarities than upland or upstream channel slopes. I conclude that adjacent sites are important for floristic recovery of riparian reaches and that demonstration restoration is most advantageous for riparian recovery. I recommend protection of upland sites from forestry to facilitate recovery. / Local- and landscape-scale effects on biodiversity after stream restoration

The riparian forests are hotspots of biodiversity and serve important roles in maintainingthe water quality. The study and understanding of this ecosystem is basic to know how theriparian zones respond to the threat and the changes produced by the urbanization. Theobjective of this pilot study was to know the species richness and check the status of theriparian vegetation along two different rivers in Halmstad, Nissan and Fylleån. The studywas focus on the status of trees at both rivers to see if the proximity of the city has anyimpact on the biodiversity. In total 9 different species were found, nevertheless only 3 ofthese species were founded on both localizations: Quercus robur, Betula pendula and Pinussylvestris. The Shannon Index showed a higher biodiversity on Nissan riparian zones, whichis the river that present the urban component. The urban area is the one that presentshigher level of biodiversity, tree species and number of individuals but there are notenough to be in a good standard. The result just show that the urban area is in a bettercondition that the natural one. The institutional efforts should be focusing on preserveboth environments with special attention to the natural environment.

abstract: When consumers make experiential purchases, they often have to decide between experiences that contain many or few features. Contrary to prior research demonstrating that consumers prefer feature-rich products before consumption but feature-poor products after consumption, the author reveals a reversal of this effect for experiences. Specifically, the author hypothesizes and finds that consumers prefer feature-poor experiences before consumption (a phenomenon denoted as `feature apprehension') but prefer feature-rich experiences after consumption. This feature apprehension occurs before consumption because consumers are concerned with the uncertainty associated with attaining a satisfying outcome from the experience. Manipulating the temporal distance with which consumers view the experience can attenuate this effect. Additionally, locus of control and social signaling moderate consumers' post-consumption preference for feature-rich experiences. The author proposes several recommendations for consumers and providers of experiences. / Dissertation/Thesis / Doctoral Dissertation Business Administration 2015

With close to 2100 species, the flowering plant genus Carex (Cyperaceae; sedges) is an example of an evolutionary radiation. Despite its potential for use as a model taxon in evolutionary studies, the diversification of sedges remains largely unexplored. This thesis realizes the potential of Carex as an evolutionary model group by using it to ask questions about species richness patterns. More specifically, it seeks to determine the relationship, if any, between rates of trait evolution and species richness. This tests the hypothesis that organisms with increased abilities to evolve new traits, speciate more rapidly. Morphological and ecological (habitat and climatic niche) traits are modelled on a nearly complete regional (North America north of Mexico) phylogeny and rates of trait evolution are compared among non-nested sister groups. However, before trait evolution is modelled, this work evaluates the sensitivity of climatic niche estimates to underlying distribution datasets. It tests the agreement of niche estimates derived from the commonly used online repository GBIF (the Global Biodiversity Information Facility) and county-level distributions via BONAP (the Biota of North America Program). Results showed that in the context of phylogenetic comparative analyses, it is not vital to obtain highly accurate climatic niche estimates. The second study found significant positive correlations between the rates of climatic niche, habitat and reproductive morphological evolution and species richness. This result supports the role of high trait lability in generating species richness and more generally, the idea that high trait disparity through evolutionary time leads to species success.

I evaluated effects of 5 pine plantation establishment regimes 6 – 8 years postestablishment on loblolly pine (Pinus taeda) growth, vegetation characteristics, nutritional carrying capacity for white-tailed deer, and breeding birds in the Lower Coastal Plain of Mississippi. Treatments combined mechanical site preparation (MSP), chemical site preparation (CSP), and herbaceous weed control (HWC) designed to represent a range of operational intensities. Chemical SP provided greater long-term control of woody competition than MSP, but did not provide significant pine growth advantage. Vegetation richness, diversity, and structure were best maintained with MSP and year 1 banded HWC. Canopy cover appears to be shading out herbaceous understory and altering composition of woody understory toward more shade-tolerant species. Total forage biomass and 3 levels of carrying capacity declined on average 54% each year. Avian metrics decreased as treatment intensity increased. Regionally important species were influenced positively by greater vegetation coverage attained by banded HWC.

No description available.

The geographic variation of taxonomic richness may be directly determined by climate through contemporaneous/ecological processes, versus other (e.g., historical/evolutionary processes) that happen to be collinear with contemporaneous climate. In Chapter 1 I evaluated hypotheses from both groups of explanations in North America. If contemporaneous climate controls patterns of richness, then richness should vary with climate through time in the same way that richness varies with current climate through space. Over the last ca. 11,000 yr, richness-temperature relationships remained reasonably constant. Between 12,000 and 14,000 yr BP, when climate fluctuated rapidly, richness gradients as a function of temperature were significantly shallower. If historical climate over the last 21,000 years determines patterns of richness, then historical climate should be a better predictor of richness than contemporaneous climate. I rejected historical-climate as a better predictor of richness. Contemporaneous climate stands as the most plausible explanation for contemporaneous patterns of richness, at least over the last 11,000 yr. In Chapter two, I tested the prediction that richness of most taxa should increase with temperature in all but the warmest and driest areas. Climate warming during Pleistocene-Holocene transition led richness increases in wet areas, but richness declines in dry regions, as expected from current richness-climate relationships. A decline in small mammal species richness in Northern California since the late Pleistocene was expected from the current richness-climate relationship for this group in North America. These results contest the view that future global warming may lead to species extinction rates that would qualify as the sixth mass extinction in the history of the earth. In chapter three, I first tested the hypothesis that richness gradients mainly reflect the sum of individual species climatic tolerances. I tested this hypothesis for birds, mammals and trees native to eastern North America (ENA, where there are no major barriers to dispersal). The number of species present in any given area in ENA is usually much smaller than the number of species in the continental pool that tolerate the climatic conditions in that area. Second, I tested several explanations for patterns of unfilled potential richness. Unfilled potential richness is inconsistent with postglacial dispersal lags, climatic variability since the Last Glacial Maximum, or with biotic interactions. In contrast, unfilled richness is highly consistent with a probabilistic model of species climate occupancy. Individual species climatic tolerances is not the process generating the main current patterns of richness, nor are post-glacial dispersal lags, climatic variability since the LGM or biotic interactions. This thesis is consistent with the hypothesis that contemporaneous climate directly controls spatial patterns of richness. Generally, there seems to be little need to invoke historical processes as determinants of current gradients of richness.

The long-term effects of large-scale changes in forestry, agriculture and other land use on habitats and the large-scale expansion of wind farming  affects bats foraging environments. In order to predict consequences of exploitations on local bat species and populations, good surveys are important. To get good background information for an Environmental Impact Assessment (EIA) it  is crucial to rapidly assess which areas are most important for bats. The aim of this work was to measure the importance of the two types of forest environment for bats foraging : forest areas located close to or far from the lakes. Bat activity and species diversity was measured with automatic ultrasound recorders in 211  nights of fieldwork at 155 locations in 23 areas in different parts of Sweden during June, July and the first two weeks of August 2011 and 2012. A total of 11 species were recorded in forest far from lakes and 8 species in forest close to lakes. Eptesicus nilssonii , Myotis sp. and Pipistrellus pygmaeus were the most common taxa in both habitat types. Activity levels were higher in the vicinity of lakes compared to forests far away from lakes. Species diversity calculated on base on Chao 2 was similar for both types of habitats . The results suggest that the forests close to lakes are the most important habitats to surveys for bats in Sweden and that inventory efforts should be primarily invested in them.

Environmental and physical conditions are considered primary drivers of fish community assemblages. The anthropogenic alteration of aquatic ecosystems is implicated as a primary threat to fisheries worldwide. In riverine ecosystems, river-wide barriers may alter natural fluvial processes and hinder fish movement through the system. In this study, I use data collected from two successive years (2008 and 2009) of intensive quantitative electrofishing Casselman and Marcogliese (2008, 2009) performed in different seasons (late fall and late summer) on the lower Ottawa and Mississippi River systems, Ontario, to investigate the effects of sampling season, distance from the river mouth, water temperature, conductivity, rank of velocity and dams on fish abundance, species richness and the Shannon-Weiner Index (SWI) as a measure of species diversity. Sampling in late summer, compared with late fall, resulted in greater species richness and diversity. Colder water temperature affected community composition, and species richness decreased upstream, while diversity did not change. In both seasons, the distance from the river mouth influenced fish community composition, whereas dams appeared to have no effect. This suggests that the continuous gradient model of the River Continuum Concept (RCC) would be applicable in these fragmented systems, which are not heavily altered by fractionation. To effectively manage cost and accuracy when collecting fish community data in large rivers, it is essential to sample strategically during seasons likely to maximize diversity and richness. Sampling intensively during warm water months in various river reaches would likely provide the most complete representation of fish assemblage. / Thesis (Master, Biology) -- Queen's University, 2013-01-17 15:36:05.658