Dispersal and metacommunity dynamics in a soft-sediment benthic system : how well is the seafloor connected?

Connectivity depends on rates of dispersal between communities. For marine soft-sediment communities continued small-scale dispersal as post-larvae and as adults can be equally important in maintaining community composition, as initial recruitment of substrate by pelagic larvae. In this thesis post-larval dispersal strategies of benthic invertebrates, as well as mechanisms by which communities are connected were investigated. Such knowledge on dispersal is scarce, due to the difficulties in actually measuring dispersal directly in nature, and dispersal has not previously been quantified in the Baltic Sea. Different trap-types were used underwater to capture dispersing invertebrates at different sites, while in parallel measuring waves and currents. Local community composition was found to change predictably under varying rates of dispersal and physical connectivity (waves and currents). This response was, however, dependent on dispersal-related traits of taxa. Actively dispersing taxa will be relatively better at maintaining their position, as they are not as dependent on hydrodynamic conditions for dispersal and will be less prone to be passively transported by currents. Taxa also dispersed in relative proportions that were distinctly different from resident community composition and a significant proportion (40 %) of taxa were found to lack a planktonic larval life-stage. Community assembly was re-started in a large-scale manipulative field experiment over one year across several sites, which revealed how patterns of community composition (α-, β- and λ-diversity) change depending on rates of dispersal. Results also demonstrated that in response to small-scale disturbance, initial recruitment was by nearby-dominant species after which other species arrived from successively further away. At later assembly time, the number of coexisting species increased beyond what was expected purely by local niche requirements (species sorting), transferring regional differences in community composition (β-diversity) to the local scale (α-diversity, mass effect). Findings of this thesis complement more theoretical studies in metacommunity ecology by demonstrating that understanding how and when individuals disperse relative to underlying environmental heterogeneity is key to interpreting how patterns of diversity change across different spatial scales. Such information from nature is critical when predicting responses to, for example, different types of disturbances or management actions in conservation.

Spatialization of climate, physical and socioeconomic factors that affect the dairy goat production in Brazil and their impact on animal breeding decisions

Brazil has high climate, soil and environmental diversity, as well as distinct socioeconomic and political realities, what results in differences among the political administrative regions of the country. The objective of this study was to determine spatial distribution of the physical, climatic and socioeconomic aspects that best characterize the production of dairy goats in Brazil. Production indices of milk per goat, goat production, milk production, as well as temperature range, mean temperature, precipitation, normalized difference vegetation index, relative humidity, altitude, agricultural farms; farms with native pasture, farms with good quality pasture, farms with water resources, farms that receive technical guidance, family farming properties, non-familiar farms and the human development index were evaluated. The multivariate analyses were carried out to spatialize climatic, physical and socioeconomic variables and so differenciate the Brazilian States and Regions. The highest yields of milk and goat production were observed in the Northeast. The Southeast Region had the second highest production of milk, followed by the South, Midwest and North. Multivariate analysis revealed distinctions between clusters of political-administrative regions of Brazil. The climatic variables were most important to discriminate between regions of Brazil. Therefore, it is necessary to implement animal breeding programs to meet the needs of each region.

A bull breeding soundness evaluation system with greater emphasis on scrotal circumference

Abstract: Bull breeding soundness evaluation (BBSE) is a method applied to reduce the risk of using subfertile bulls in herds. There are currently two BBSE systems, those of the Society for Theriogenology (SFT) and the Western Canadian Association of Bovine Practitioners (WCABP). Scrotal circumference (SC), sperm motility (SM) and normal sperm (NS) of 454 bulls aged between 12 and 15 months of a Spanish beef breed were used to compare both systems, and since there is no agreement on that BBSE system must be applied in Spain, a single one was proposed for its consideration. SC was adjusted to 15 months (SC15) and the mean of the BBSE traits was: SC15 (34.2±2.4cm), SM (76.6±14.6%) and NS (76.8±12.3%). In the PROPOSED system, the SM and NS thresholds were those defined by the WCABP system, while the SC15 thresholds were set by combining the SFT threshold and SC15±1SD in order to establish four classification categories, the three proposed by the WCABP system: unsatisfactory, questionable and satisfactory, and other category, called superior, for bulls with SM≥60%, NS≥70% and SC15≥Mean+1SD. The PROPOSED system scored fewer bulls as unsatisfactory than the SFT and the WCABP systems (8.6%, 23.6% and 22.5%, respectively; P<0.01), while the percentage of bulls from worst to best in the other three categories under the PROPOSED system was: 26.0%, 54.2% and 11.2%, respectively. In conclusion, the PROPOSED system gives more emphasis to SC, sets differences between bulls classified as satisfactory by the other systems and can be considered a good system for Spain and for other countries that have no defined their own system.

Mathematics inspired by Darwin. Adaptive dynamics of dispersal and cooperation

In 1859, Charles Darwin published his theory of evolution by natural selection, the process occurring based on fitness benefits and fitness costs at the individual level. Traditionally, evolution has been investigated by biologists, but it has induced mathematical approaches, too. For example, adaptive dynamics has proven to be a very applicable framework to the purpose. Its core concept is the invasion fitness, the sign of which tells whether a mutant phenotype can invade the prevalent phenotype. In this thesis, four real-world applications on evolutionary questions are provided. Inspiration for the first two studies arose from a cold-adapted species, American pika. First, it is studied how the global climate change may affect the evolution of dispersal and viability of pika metapopulations. Based on the results gained here, it is shown that the evolution of dispersal can result in extinction and indeed, evolution of dispersalshould be incorporated into the viability analysis of species living in fragmented habitats. The second study is focused on the evolution of densitydependent dispersal in metapopulations with small habitat patches. It resulted a very surprising unintuitive evolutionary phenomenon, how a non-monotone density-dependent dispersal may evolve. Cooperation is surprisingly common in many levels of life, despite of its obvious vulnerability to selfish cheating. This motivated two applications. First, it is shown that density-dependent cooperative investment can evolve to have a qualitatively different, monotone or non-monotone, form depending on modelling details. The last study investigates the evolution of investing into two public-goods resources. The results suggest one general path by which labour division can arise via evolutionary branching. In addition to applications, two novel methodological derivations of fitness measures in structured metapopulations are given.

Floral biology and breeding system of three Ipomoea weeds

The floral biology of three weeds, Ipomoea cairica, I. grandifolia and I. nil (Convolvulaceae), was studied in Botucatu and Jaboticabal, São Paulo, in southeastern Brazil. The three species are melittophilous, with a varied set of floral visitors, but with some overlapping. Cluster analysis using Jacquard similarity index indicated a greater similarity among different plant species in the same locality than among the populations at different places, in relation to floral visitor sets. The promiscuous and opportunistic features of the flowers were shown, with such type of adaptation to pollination being advantageous to weeds since pollinator availability is unpredictable at ruderal environments.

Phenology, fruit set and dispersal of Cordia multispicata Cham., an important weed shrub of abandoned pastures in eastern Amazonia

ABSTRACT - (Phenology, fruit set and dispersal of Cordia multispicata Cham., an important weed shrub of abandoned pastures in eastern Amazonia). The reproductive ecology of the distylous tropical shrub Cordia multispicata was studied in an abandoned pasture in Paragominas County , Pará state, Brazil. It is a common species in the Amazon basin where it occurs as a weed in open and disturbed habitats. C. multispicata has many flowers per inflorescence (85 ± 12) but 84% abort before fertilization. Flowering occurs throughout the year. Fruits are small, with a red fleshy pericarp (skin-pulp) attractive to birds. Fruit set is lower during the dry season (less than 30%) and higher during the rainy season when there are many visits of insects to the flowers. Fruiting has a peak between the end of the dry season and the middle of the rainy season. Nineteen bird species were observed foraging for the fruits of C. multispicata, and 79% of those species can be considered as potential dispersal agents. The efficient seed dispersal and aggregated spatial distribution associated with some characteristics of the dispersors greatly contributed to the success of this species in abandoned pastures of eastern Amazonia.

Seed characteristics and dispersal of dimorphic fruit segments of Cakile maritima Scopoli (Brassicaceae) population of southern Brazilian coastal dunes

Cakile maritima occurs sporadically along the southern Brazilian coast, where it is restricted to more protected sites at the base of foredunes. Somatic dimorphism in C. maritima is manifested as morphologically distinct upper and lower fruit segments (silicules). The two morphs were tested for differences in size, number of seeds, dispersal ability and natural establishment. In the C. maritima population of southern Brazil, the lower silicule has more seeds than upper silicule, and lower seeds are more likely to abort than the upper ones. Seeds from upper segments were significantly larger than those from lower ones; however, their mass ranges overlap. The mean silicule mass was not significantly different from both segments, but the silicule/seed mass ratio from upper and lower segments was significantly different. Both segments had high ability to float in sea water, more than 50% were still afloat after 70 days. Nevertheless, dispersal occurs mainly to landward due to dominant wind action. Most of the seedlings were restricted to within a one-metre radius of the mother plant, and were principally derived from lower fruit segments.

Reproductive phenology, pollination and seed dispersal syndromes on sandstone outcrop vegetation in the "Chapada Diamantina", northeastern Brazil: population and community analyses

Vegetation on rock outcrops in the "Chapada Diamantina" (soil islands) is often aggregated and surrounded by nude rock surfaces, thus creating natural units with well defined limits. The flowering and fruiting cycles of plants on 58 soil islands at altitudes between 1,100 and 1,140 meters above sea leavel were analyzed at Mãe Inácia Peak (12°27' S and 41°28' W) in the "Chapada Diamantina", Bahia, Brazil. The presence/absence of flowering and fruiting species on each soil island, and their respective cover areas were analyzed at both the population and community levels, and the phenophases of flowering and fruiting were observed during 24 successive months. The analyses of pollination and seed dispersal syndromes indicated that animals are more important in pollination than in seed dispersal (which is predominantly by anemochory and autochory). The flowering and fruiting of plants with animal pollination syndromes were correlated with rainfall and temperature. The flowering season varied during the year according to the pollination syndrome involved: entomophily was predominant from summer through autumn, ornithophily was predominant during winter, and anemophily in the spring. The staggered timing of flowering and fruiting among different species provides a nearly continuous supply of resources for the local fauna.

Clonal growth and dispersal potential of Leiothrix flagellaris Ruhland (Eriocaulaceae) in the rocky grasslands of Southeastern Brazil

Leiothrix flagellaris is a small clonal plant that grows in sandy/rocky, nutrient poor soils in the rocky grasslands ("campos rupestres") of southeastern Brazil. In the rainy season most of their flower heads differentiate into small rosettes, produced by pseudovivipary, and connected to the mother-plant by flexible, elongated stalks that can reach up to 90cm. Most of these rosettes remain suspended over rocks or over the sparse herbaceous surrounding vegetation, while a few arch low enough to come into contact with the surrounding soil and take root. These suspended rosettes can reach diameters comparable to currently rooted and reproductively active rosettes produced during previous reproductive periods. As the rooted rosettes grow up, their potential to generate and disperse new pseudoviviparous rosettes increase rapidly. This unusual guerrilla strategy of L. flagellaris seems to congregate a suit of traits that promote a fast increase in photosynthetic area and improve recruitment, thereby helping to circumvent dispersal and establishment failures in its severe environment.

Dispersal modes and fruiting periods in hyperseasonal and seasonal savannas, central Brazil

Seasonal savannas are characterized by an intense drought that influences their functioning. Hyperseasonal savannas experience additionally a waterlogging during the rainy season. In South America, the largest savanna environment is the Brazilian cerrado. To assess whether a particular dispersal mode or fruiting period is associated to the waterlogging, we examined dispersal and phenological groups in hyperseasonal and seasonal cerrado plant species. We compared the proportion of species and individuals in these groups with G-tests for independence in contingency tables. We did not find differences in the proportion of species; however, based on the proportion of individuals, the main dispersal strategy was anemochory in the hyperseasonal cerrado and zoochory in the seasonal cerrado. Phenological strategies of fruiting in safe periods of the year were differently selected in both cerrados. In the hyperseasonal cerrado, most individuals fruited in non-waterlogged periods, whereas in the seasonal cerrado, most individuals fruited in wetter periods. Thus, waterlogging may drive important modifications in the efficiency of the dispersal and phenological strategies of hyperseasonal savannas plants.

Alternative procedures for parent choice in a breeding program for the common bean (Phaseolus vulgaris L.)

Six common bean cultivars were crossed in diallel and the segregant populations were assessed in the F2 and F3 generations to compare methodologies for parental selection in a breeding program based on hybridization. The cultivars involved in the diallel were A 114, A 77, ESAL 686, Milionário, Carioca, and Flor de Mayo. The segregant F2 and F3 generations were assessed on the experimental campus of the Universidade Federal de Larvas, in July 1994. It was found that the cultivars differed in their general combining ability (GCA). Flor de Mayo, which belongs to the Durango race, had the largest positive GCA estimate for grain field, and the cultivars from the Mesoamerican race, Milionário and A 114, the smallest GCA estimates. For flowering, the cultivar that most contributed to reduced plant cycle was ESAL 686. There was agreement among the results obtained from the diallel and the estimates of the parameter m + a of the populations. However, it was evident that the estimate of genetic variance of the populations should be considered as a condition to identify the hybrid population that will produce a line with high performance.

The influence of investigator disturbance on aggressive behaviour and breeding success of ring-billed gulls (Larus delawarensis) /

Increased losses of eggs and chicks resulting from human intrusion (investigator or other) into seabird colonies has been well documented. In 1990/91, I studied the effects of investigator disturbance on aggressive behaviour and breeding success of individual pairs of ring-billed gulls nesting at two colonies near Port Colborne, Ontario. The insular colony was on an artificial breakwall, associated with the Welland Ship Canal, approximately 1 km off the north shore of Lake Erie. The mainland colony was adjacent to the canal approximately 1 km east of the breakwall. The frequencies of adult threat and assault behaviours, chick movement and adult attacks on chicks were recorded by continuous scan sampling 30 min prior to, 30 min during and 60 (2 X 30) min after investigator disturbance. The frequency of threat and assault behaviours increased during the period of investigator activity in the colony while the duration of wingpulls and beakpulls decreased. Significantly more chicks ran ("runners") from their natal territories during disturbances and "runners" were more frequently attacked than "territorial" chicks. No chicks were fatally attacked during disturbance and "runners" returned to their natal territories quickly after disturbance. Breeding success was determined for pairs nesting in study plots subjected to two levels of disturbance (normal and moderate). The disturbance level of each plot differed in visitation frequency and activities performed on each visit. Investigator disturbance had no effect on the hatching success or fledging success (taken as 21 days of age) of ring-billed gull study pairs at either colony.

Drift dispersal in central Southern Ontario /

Two tills are readily identi-f i able in central Southern Ontario, a very stony, loose deposit o-f variable matrix (Dummer till) and a moderately stony, fissile and compact deposit that is more homogeneous (drumlinized till). The quantity o-f Precambr i an, Paleozoic and Shadow Lake Formation (Paleozoic) rock types were determined and corresponding isopleth maps drawn. The changes in lithology content occurred in the direction o-f transport, there-fore, compositional isopleths o-f till may be considered equipotential lines for the reconstruction of glacier flow paths. Areal gradations of drift lithology indicated that the prime agents of dispersal were ice and glacial meltwaters. The down-ice abundance trend of till components indicated a dispersal pattern showing the concentration of a given lithology type peaking within a few kilometres of the source followed by a rapid decline and thereafter, a more gradual decrease with increasing distance. Within the esker deposits, igneous rocks may form the major component and can extend further onto the limestone plain than in the adjacent till. Evidence is presented that indicates the "style" of dispersal was one in which glacial ice may have been strongly influenced by local bedrock topography and the regional structural trends. The ice tended to follow pre-existing valleys and lows, depositing till composed mainly of local bedrock. Gradations in Paleozoic clast content showed that the local bedrock lithology became the primary till component within 3 km of down-ice transport. Evidence is presented that indicated the last glaciation may have occurred as a relatively thin ice mass, followed by stagnation and recession. No evidence of a lateglacial re-advance was found within the study area. Because of the lack of a contact between the Dummer and drumlinized till, and because of results showing gradation of the Dummer till into the drumlinized till (as indicated by lithology content and grain size), it is suggested that no re-advance occurred.

Breeding parameters of great cormorants (Phalacrocorax carbo carbo) at mixed species colonies on Prince Edward Island, Canada

Breeding parameters of Great Cormorants (PkaZac/iOCOfiCLX CCUibo dCUtbo) and Double-crested Cormorants (P. CLU/uXuA CMJhLtllb) were examined at two mixed species colonies at Cape Tryon and Durell Point, Prince Edward Island from 1976 to 1978. Differential access to nests at the two colony sites resulted in more complete demographic data for P. CCUibo than for P. CLUJiituA. In 1911j P. CCtfibo was present at both colonies by 21 March, whereas P. auAAJtuA did not return until 1 April and 16 April at Cape Tryon and Durell Point, respectively. Differences in the arrival chronology by individuals of each species and differences in the time of nest site occupation according to age, are suggested as factors influencing the nest site distribution of P. CXUtbo and P. aiVtituA at Cape Tryon. Forty-eight P. dOJtbo chicks banded at the Durell Point colony between 19 74 and 19 76 returned there to nest as two- to four-year olds in 19 77 and 19 78. Unmarked individuals with clutch-starts in April were likely greater than four years old as all marked two to four-year olds (with one possible exception) in 19 77 and 1978 had clutch-starts in May and June. Seasonal variation in the breeding success of P. dOJibo individuals was examined at Durell Point in 1977. Mean clutch-size, hatching success and fledging success exhibited a seasonal decline. Four- and 5-egg clutches represented the majority (75%) of all P. CCUibo clutches at Durell Point in 1977 and had the highest reproductive success (0.48 and 0.43 chicks fledged per egg laid respectively). Smaller clutches produced small broods with significantly higher chick mortality while larger clutches suffered high egg loss prior to clutch completion.

Selected aspects of the breeding biology of two Lake Erie herring gull colonies

Aspects of the breeding biology of two Lake Erie Herri ng Gull colonies were studied in 1975 and 1976. In 1976 the incubation attention given 2-egg and 3-egg clutches initiated early and late in the season was measured. Brood size at one colony was artificially increased or decreased by addition of chicks shortly after hatching. Hatching success was not consistently re~ated to clutch size but early nesters were more successful than late nes'ters. Differences in hatching success between 2-egg and 3-egg clutches were a function of the time of clutch initiation with the clutch size having the greater proportion of its nests initiated early in the season being more successful. The incubation attentiveness of parents of 2-egg and 3-ev,g , and early and late clutches was similar. Most nests were incubated greater than 95% of the time although t heir hatching success was similar ' to those incubated less than 75% of the time. Fledging success, chick growth and weight at fledging were similar among broods of one, two and three chicks and artificially increased broods of four and five chicks. Fledging success was highest for o.e chick broods reduced from two and three chick broods.