How has water shaped the history of a region that is bordered by ocean, brimming with ephemeral rivers, and yet prone to drought? This article explores water histories in Southern Africa over the past two hundred years. Using oral traditions, epic poetry, archival sources, and secondary anthropological and archaeological literature, I examine how Africans and Europeans related to, claimed, and used different bodies of water. In the first section I discuss how water was central to isiNguni conceptions of social and political life. In the second section I discuss how European empires used water to enclose and dispossess African land and to build hydropolitical colonial orders over the nineteenth and twentieth centuries. I conclude by reflecting on afterlives of these water histories in the present.

La adaptación de los mayas postclásicos a las nuevas condiciones de vida surgidas a raíz de la crisis generalizada del final del período Clásico mediante respuestas resilientes se ha convertido en un tema de creciente interés por parte de los investigadores mayistas en las últimas décadas. El estudio de vestigios arqueológicos adscritos al Postclásico puede ayudar a entender por qué ciertas tradiciones fueron abandonadas, mientras que otras han perdurado a lo largo del tiempo, como es el caso de las ceremonias del culto a la lluvia. Ejemplo de ello son los hallazgos de ofrendas y otros vestigios arquitectónicos realizados en Chilonché, un antiguo asentamiento urbano maya fundado en la cuenca del río Mopán (Petén), cuya arquitectura y manifestaciones artísticas son un fiel exponente de la importancia política que tuvo el sitio en su dilatado período de ocupación. Los resultados de esta investigación, que combina los estudios arqueológicos y arquitectónicos con los análisis arqueométricos e iconográficos de las piezas cerámicas exhumadas, permiten afirmar que las ofrendas postclásicas halladas en un palacio de la acrópolis de Chilonché están íntimamente ligadas al acto de verter agua y a la imagen de Chaahk, y por lo tanto a rituales vinculados a la lluvia.

In one of his fragments, Empedocles addresses his protégé Pausanias, predicting or promising that he will learn pharmaka, a word that is usually understood to mean herbal ‘drugs' or ‘remedies’ for disease, an interpretation that in turn seems to have been encouraged by a modern understanding that Empedocles was an empirically minded medical doctor. An alternate interpretation is suggested, however, by the recently published Getty Hexameters which use the word pharmaka several times to refer to hexametrical incantations that will protect a group of houses or a city from danger. These hexameters, moreover, are inscribed on a lead tablet of late-classical date that most probably came from the Sicilian city of Selinus, a date and a provenance that put its composition in close proximity to Empedocles himself.

Climate change will alter rainfall patterns. The effect of rainfall during seed development and maturation on wheat (Triticum aestivum L.) seed quality (ability to germinate normally; air-dry longevity in hermetic storage at 40°C with c. 15% moisture content) was investigated in field experiments (2011, 2012) by providing rain shelter or simulating additional rainfall. High ability to germinate was detected from mid seed filling until after harvest maturity. Subsequent longevity was more sensitive to stage of development. It increased progressively, reaching maximum values during maturation drying at 53–56 days after anthesis (DAA), 5–11 (2011) or 8–14 (2012) days beyond mass maturity; maximal values were maintained thereafter in 2011; longevity declined with further delay to harvest in 2012. Post-anthesis protection from rain had no major effect: in later harvests longevity was slightly greater than the control in each year, but in 2011 wetting treatments were also superior to the control. Wetting ears at all stages of development reduced longevity immediately, but considerable recovery in subsequent longevity occurred when seeds re-dried in planta for several days. The greatest damage to longevity from ear wetting occurred with treatments at about 56 DAA, with poorest recovery at 70 DAA (i.e. around harvest maturity) in absolute terms but at 56–70 DAA relative to gross damage. Hence, seed quality in a strongly dormant wheat variety was resilient to rain. Net damage was greatest from rain late in maturation. The phase of seed quality improvement in planta was dynamic with deterioration also occurring then, but with net improvement overall.

Poor wheat seed quality in temperate regions is often ascribed to wet production environments. We investigated the possible effect of simulated rain during seed development and maturation on seed longevity in wheat (Triticum aestivum L.) cv. Tybalt grown in the field (2008, 2009) or a polythene tunnel house (2010). To mimic rain, the seed crops were wetted from above with the equivalent of 30 mm (2008, 2009) or 25 mm rainfall (2010) at different stages of seed development and maturation (17–58 DAA, days after 50% anthesis), samples were harvested serially, and subsequent air-dry seed longevity estimated. No pre-harvest sprouting occurred. Seed longevity (p50, 50% survival period in experimental hermetic storage at 40°C with c. 15% moisture content) in field-grown controls increased during seed development and maturation, attaining maxima at 37 (2008) or 44 DAA (2009); it declined thereafter. Immediate effects of simulated rain at 17–58 DAA in field studies (2008, 2009) on subsequent seed longevity were negative but small, e.g. a 1–4 d delay in seed quality improvement for treatments early in development, but with no damage detected at final harvests. In rainfall-protected conditions (2010), simulated rain close to harvest maturity (55–56 DAA) reduced longevity immediately and substantially, with greater damage from two sequential days of wetting than one; again, later harvests provided evidence of recovery in subsequent longevity. In the absence of pre-harvest sprouting, the potentially deleterious effects of rainfall to wheat seed crops on subsequent seed longevity may be reversible in full or in part.

The aim of this study was to analyse the spatio-temporal dynamics of Toxoplasma gondii infection in long-term monitoring of domestic cats (8–15 years) in three populations living in rural France. Overall seroprevalence was 52·7% (modified agglutination test ⩾1:40). Incidence was 0·26–0·39 seroconversions/cat per year, and the estimated rate of soil contamination by T. gondii oocysts ranged between 31 and 3600 oocysts/m2 per year, depending on the population. Incidence risk in cats was related to mean precipitation, explaining both the spatial and temporal variability in risk: local conditions explained differences between the three study sites and incidence risk increased during rainy years. This study brings rare quantitative information on the level of contamination of the environment by T. gondii oocysts, and suggests that the spatio-temporal distribution of incidence risk in cats may reflect both the influence of rain on prey populations and infectivity of T. gondii oocysts.

The effects of predators on prey populations can be modified by a number of abiotic factors. Here, we investigated the combined and separate effects of rain and ground-dwelling predators on aphid populations in a microcosm experiment lasting for 21 days, using PCR to analyse the gut content of the predators. Rain significantly dislodged aphids from shoots and ears by 57% and 25%, respectively. The gut content analysis showed that more predators consumed aphids in the rain treatment than without rain, indicating higher availability of aphids to ground-dwelling predators after rain. However, no synergistic effects of rain and ground-dwelling predators on aphid population development could be demonstrated. Rain alone significantly decreased aphid populations by 27%, suggesting that this is a significant mortality factor. Predators alone had no significant effect on aphid numbers, but the gut content analyses showed aphid consumption also in the no-rain treatments, indicating that aphids were available to the predators on the soil surface even without rain. Our results suggest that weather conditions such as rain can modify predator-prey interactions in the field. Employing PCR-based predator gut content analyses proved to be useful as trophic links could be directly verified.

Uptake and loss of water by six lichen species from the Argentine Islands, Antarctic Peninsula, were studied in their natural habitat and in laboratory studies. Under field conditions, during a period of rain, uptake of moisture ranged from 15% d w h−1 for Usnea antarctica to almost 90% for Mastodia tesselata. Loss rates after the rain ceased were lower than the uptake rates and ranged from 8.5% d w.h−1 in Umbilicaria decussata to 38.8% in M. tesselata. A comparison of thalli of M. tesselata from the shoreline with thalli collected further inland showed significant differences in maximum water content and in rates of water loss and uptake between thalli from these sites, which could be ascribed to the presence of salt in the thalli of M. tesselata from the shore. Thallus samples of Usnea antarctica collected from an exposed site showed lower uptake rates and higher loss rates of water than samples collected from a more sheltered site. Under laboratory conditions the maximum moisture content ranged from 67% in Usnea antarctica to 391% in M. tesselata. Exposed to an atmosphere of c. 40% relative humidity and c. 15°C, lichen thalli lost their water during the first hour of the experiment at rates ranging from 34% of the maximum moisture content in Umbilicaria propagulifera to 70% in U. decussata. Rates of water loss diminished with time, and after 4–6 hours equilibrium was reached, with water contents of 14–16% of thallus dry weight. The microclimate is the driving force for the thallus water regime. Specific differences in rates of water loss and water uptake depend on the morphology and anatomy of the lichen thalli. The results of the laboratory experiments agree with those from the field study. However, local differences in microclimatic or other environmental factors can be responsible for significant differences in the water regime of thalli of the same species, a result which can only be obtained from field studies.