Summary1 Patterns of seed germination of grass and forb species were studied in open Prosopis woodland of the central Monte desert (Argentina) during several years, to test the hypotheses that (i) seed germination is positively aected by both rainfall and protection aorded by vegetation cover (a facilitative eect), (ii) the number of surviving plants is positively in¯uenced by rainfall but negatively aected by established vegetation (a competitive eect), and (iii) seed loss from soil banks owing to germination is lower than that caused by granivorous animals. 2 Forb species germinated during restricted periods, either in early autumn or in spring. Grasses, however, germinated throughout the growing season, but because seedlings could not be identi®ed to species level, it was impossible to discern whether dierent species germinated in particular seasons, or if all grasses germinated in all seasons. Grass and forb germination were generally of similar magnitude, but grass germination increased by an order of magnitude during a summer of unusually abundant rainfall related to an El NinÄ o Southern Oscillation (ENSO) event.3 Overall, the spatial distribution of neither germinating seeds nor surviving plants could be explained by interactions with established vegetation (facilitation and competition eects, respectively). An alternative explanation may be provided by the distribution of forb and grass seeds in the soil. 4 Seed loss owing to germination was low in both dry and rainy years. For forbs, such loss totalled < 1% of soil-seed reserves, and no forb species suered losses > 4%. Total grass-seed loss to germination was usually < 0.5%, and the 5% reached in 1997±98 corresponded to an interruption of a prolonged drought by unusually abundant rainfall associated with a reduced seed bank. 5 Grass-seed loss caused by germination was one to two orders of magnitude lower than that reported due to autumn-winter granivory in the central Monte desert.

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There are currently serious concerns that published scientific findings often fail to be reproducible, and that some solutions may be gleaned by attending the several methodological and sociological recommendations that could be found in the literature. However, researchers would also arrive at some answers by considering the advice of the philosophy of science, particularly semantics, about theses on truth related to scientific realism. Sometimes scientists understand the correspondence thesis of truth (CTT) as asserting that the next unique empirical confirmation of a hypothesis suffices to attribute truth to it provisionally. Such empiricist bias is not necessarily at the core of CTT, but Mario Bunge proposed the synthetic thesis of truth (STT), based on CTT, to explicitly avoid the bias. STT requires considering a hypothesis corroborated, both by purely empirical confirmation and external consistency or compatibility with the bulk of existing background knowledge (systemicity). While a capricious understanding of CTT could be rigged to recommend the “one shot game” in hypothesis testing, STT clearly demands the use of multiple approaches, empirical as well as theoretical, and it asserts that a scientific test is effective to the extent to which it is neither purely empirical, nor viewed in isolation. Pattern consistency (empirical control) together with an understanding of causal relations (rational together with empirical control) make confirmed hypotheses robust and more reliable. The militancy of the double mechanism of hypothesis control of STT can help mitigate the reproducibility crisis. Earl Werner’s research program in community ecology is an example of the (implicit) use of STT criteria, which leads to the development of reliable, cross-checked, ecological results, with high predictive capacity.

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