Dormancy release in Australian fire ephemeral seeds during burial increases germination response to smoke water or heat

Fire ephemerals are short-lived plants that primarily germinate after fire. Fresh and laboratory-stored seeds are difficult to germinate ex situ, even in response to fire-related cues such as heat and smoke. Seeds of eight Australian fire ephemeral species were buried in unburnt and recently burnt sites of natural bushland during autumn. Seeds were exhumed after 6 and 12 months and incubated in water and smoke water, either with or without a heat treatment at 70 degrees C for 1 h. Generally, germination did not increase after 6 months of burial, but after 12 months of burial germination was enhanced in seven of the eight species. Actinotus leucocephalus produced higher germination following 12 months of burial without any further treatment, and smoke water and heat further improved germination. The four Gyrostemonaceae species, Codonocarpus cotinifolius, Gyrostemon racemiger, Gyrostemon ramulosus and Tersonia cyathiflora, only germinated in the presence of smoke water, and their germination was enhanced by burial. Burial improved germination in response to a heat treatment in Grevillea scapigera and Alyogyne huegelii seeds, but did not enhance Alyogyne hakeifolia germination. During concurrent dry laboratory storage of seeds at 15 degrees C, only Actinotus leucocephalus produced increased germination in response to smoke water and heat over time. In summary, soil burial can alter the dormancy status of a number of Australian fire ephemeral seeds, rendering them more responsive to germination cues such as smoke water and heat. The requirement for a period of burial before seeds become responsive to smoke and/or heat would ensure that seeds persist in the soil until a subsequent fire, when there is an increase in nutrients available for growth and reduced competition from other plants.

Government bond yield spreads in EMU countries: The story of an ephemeral convergence

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Macrophyte community structure and species occurrence in relation to environmental determinants in the ephemeral aquatic habitats of Gavdos, Greece

The aims of this study were to explore the environmental factors that determine the distribution of plant communities in temporary rock pools and provide a quantitative analysis of vegetation-environment relationships for five study sites on the island of Gavdos, southwest of Crete, Greece. Data from 99 rock pools were collected and analysed using Two-Way Indicator Species Analysis (TWINSPAN), Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) to identify the principal communities and environmental gradients that are linked to community distribution. A total of 46 species belonging to 21 families were recorded within the study area. The dominant families were Labiatae, Gramineae and Compositae while therophytes and chamaephytes were the most frequent life forms. The samples were classified into six community types using TWINSPAN, which were also corroborated by CCA analysis. The principal gradients for vegetation distribution, identified by CCA, were associated with water storage and water retention ability, as expressed by pool perimeter and water depth. Generalised Additive Models (GAMs) were employed to identify responses of four dominant rock pool species to water depth. The resulting species response curves showed niche differentiation in the cases of Callitriche pulchra and Tillaea vaillantii and revealed competition between Zannichellia pedunculata and Chara vulgaris. The use of classification in combination with ordination techniques resulted in a good discrimination between plant communities. Generalised Additive Models are a powerful tool in investigating species response curves to environmental gradients. The methodology adopted can be employed for improving baseline information on plant community ecology and distribution in Mediterranean ephemeral pools.

The opportunistic feeding and reproduction strategies of the annual fish Cynopoecilus melanotaenia (Cyprinodontiformes: Rivulidae) inhabiting ephemeral habitats on southern Brazil

A maioria dos peixes da família Rivulidae são popularmente conhecidos como anuais por completarem todo seu ciclo biológico em pequenos corpos de água temporários que secam obrigatoriamente em determinados períodos do ano causando a morte dos indivíduos adultos. Possuem características biológicas peculiares como pequeno porte, maturação sexual precoce, reprodução contínua, um elaborado padrão de corte e uma grande capacidade reprodutiva entre os peixes. Os rivulídeos se encontram amplamente distribuídos nas Américas do Norte, Central e Sul. Este trabalho analisou a dieta e a biologia reprodutiva de Cynopoecilus melanotaenia. Foram coletados 263 exemplares e a análise de 233 conteúdos gastrointestinais revelou uma dieta invertívora composta principalmente por microcrustáceos (Cladocera, Amphipoda e Ostracoda) e insetos imaturos (Chaoboridae, Culicidae, Syrphidae, mas principalmente larvas de Chironomidae). Foi registrada a lepidofagia na dieta dos machos. A fecundidade foi estimada pela análise de 59 pares de ovários maduros e variou entre 2 a 157 ovócitos (média, 19 ± 26[DP]). A espécie apresentou desova parcelada, uma estratégia para aumentar a chance de sobrevivência a depleções prolongadas. Este trabalho apresenta a primeira investigação sobre a biologia reprodutiva de C. melanotaenia. Os resultados encontrados sugerem a estratégia reprodutiva oportunista de C. melanotaenia e fornecem novas informações biológicas que podem contribuir para pesquisas de conservação e manutenção da espécie em seu ambiente natural.

Yeasts found on an ephemeral reproductive caste of the leaf-cutting ant Atta sexdens rubropilosa

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hanseniaspora nectarophila sp nov., a yeast species isolated from ephemeral flowers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Interaction between karstic aquifers and allogenic rivers: the aquifer of the national park of the ephemeral river Lobos Canyon (Spain)

A methodology is described for understanding the interaction of karstic aquifers with allogenic rivers, where little information is available. This methodology includes conventional hydrogen- ology methods tracer tests and measurements of flow into, out of and circulating within the karstic system. The method is designed to un- derstand the hydrogeological behaviour of a river in sufficient detail, given a short study pe- riod. The methodology is applied to a karstic system in Spain, obtaining useful, quantitative results for a hydrological year, such as an esti- mate of the water balance, differentiation be- tween autogenic and allogenic natural recharge, relationship and connection between the river and the aquifer, and measurements of infiltration capacity in watercourses under different hydro- logical situations. The paper deals with a useful example that could be applied to other rivers and aquifers where few data are available. It can be applied to aquifers under a natural regime and Mediterranean climate.

Ephemeral fever bibliography, 1878-July 1971 /

Mode of access: Internet.

Seasonal Fish Dispersal in Ephemeral Wetlands of the Florida Everglades

We hypothesized that fishes in short-hydroperiod wetlands display pulses in activity tied to seasonal flooding and drying, with relatively low activity during intervening periods. To evaluate this hypothesis, sampling devices that funnel fish into traps (drift fences) were used to investigate fish movement across the Everglades, U.S.A. Samples were collected at six sites in the Rocky Glades, a seasonally flooded karstic habitat located on the southeastern edge of the Everglades. Four species that display distinct recovery patterns following drought in long-hydroperiod wetlands were studied: eastern mosquitofish (Gambusia holbrooki) and flagfish (Jordanella floridae) (rapid recovery); and bluefin killifish (Lucania goodei) and least killifish (Heterandria formosa) (slow recovery). Consistent with our hypothesized conceptual model, fishes increased movement soon after flooding (immigration period) and just before drying (emigration period), but decreased activity in the intervening foraging period. We also found that eastern mosquitofish and flagfish arrived earlier and showed stronger responses to hydrological variation than either least killifish or bluefin killifish. We concluded that these fishes actively colonize and escape ephemeral wetlands in response to flooding and drying, and display species-specific differences related to flooding and drying that reflect differences in dispersal ability. These results have important implications for Everglades fish metacommunity dynamics.

Macroinvertebrate Community Composition and Diversity in Ephemeral and Perennial Ponds on Unregulated Floodplain Meadows in the UK

Ponds are common and abundant landscape features in temperate environments, particularly on floodplains where lateral connectivity with riverine systems persists. Despite their widespread occurrence and importance to regional diversity, research on the ecology and hydrology of temperate ephemeral and perennial floodplain ponds lags behind that of other shallow waterbodies. This study examines the aquatic macroinvertebrate diversity of 34 ponds (20 perennial and 14 ephemeral) on two unregulated riverine floodplain meadows in Leicestershire, UK. Perennial ponds supported nearly twice the diversity of ephemeral ponds. Despite frequent inundation of floodwater and connectivity with other floodplain waterbodies, ephemeral ponds supported distinct invertebrate communities when compared to perennial ponds. When the relative importance of physical and chemical, biological and spatial characteristics was examined, physical and chemical characteristics were found to account for more variation in community composition than biological or spatial variables. The results suggest that niche characteristics rather than neutral colonisation processes dominate the structure of invertebrate communities of floodplain ponds. The maintenance of pond networks with varying hydroperiod lengths and environmental characteristics should be encouraged as part of conservation management strategies to provide heterogeneous environmental conditions to support and enhance aquatic biodiversity at a landscape scale.

Beyond the Spanish classics - The ephemeral awakening of the history of international law in pre-democratic Spain

Cuadernos para el Diálogo (1963-1978) played a key-role in nurturing the intellectual soil for the Spanish Transition to democracy and it has spawned an extensive amount of literature among historians. This work links for the first time the course of this emblematic monthly journal with the short-lived period of methodological and historiographical innovation of Revista Española de Derecho Internacional under the direction of the international jurist Mariano Aguilar Navarro.