Precipitation plays an important role in the dynamics of species found in arid and semiarid environments. However, population fluctuations generally are driven by a combination of multiple factors whose relative contribution may vary through time and among species. We monitored fluctuations of species in three trophic levels for >17 years at a semiarid community in north‐central Chile. The region is strongly affected by the El Niño Southern Oscillation, resulting in high variation in rainfall that triggers dramatic changes in food resource availability, with strong effects on upper trophic levels. We focused our analyses on the role played by endogenous and exogenous (climatic) factors on the dynamics of two important rodent species in the community, Octodon degus and Phyllotis darwini. We documented population fluctuations of several orders of magnitude in response to wet and dry episodes of different strength and duration. P. darwini reached similar maximum densities, regardless of the duration of high‐rainfall events, whereas O. degus showed additive effects of multiple wet years. Time series diagnostic tools revealed oscillations with a 5‐year periodicity in rainfall, which may be the cause of the same periodicity and a weak second‐order signal observed in the rodent dynamics. However, the dynamics of both rodent species were dominated by strong first‐order processes, suggesting an important role of direct density dependence. Intraspecific competition, expressed as the ratio of rodent density/rainfall (or food resources) explained more than two‐thirds of the variation in the population rate of change, whereas less than one‐third was explained by lagged rainfall (or food resources). We detected no significant effects of predation. Our results contribute to a growing number of examples of dynamics governed by the combined effect of density dependence and climatic forcing. They also reveal strong bottom‐up regulation that may be common in other arid environments.

Leptospirosis is a global and re-emerging zoonotic disease caused by Leptospira spirochetes that are shed into the environment by infected animals. Humans can get infected via contact with animal hosts or contaminated environment. In Argentina, the highest annual incidences were reported in the province of Santa Fe, where epidemic outbreaks occurred during flooding events. This study examined the knowledge, attitudes and practices (KAP) regarding leptospirosis among residents of riverside slum settlements from Santa Fe after a major flood. A cross-sectional questionnaire was administered to 113 residents of 3 riverside settlements from Santa Fe. The influence of knowledge and attitudes regarding leptospirosis on the likelihood that an individual will use preventive practices were evaluated using linear mixed-effects models. The majority of respondents (83.2%) had previously heard about leptospirosis; however specific knowledge about leptospirosis was limited. The results of the modeling efforts, show that the likelihood of using preventive practices was associated with having greater knowledge score, but not with more positive attitudes. We also found that females were more likely to use safer practices than males. Even though the majority of respondents had heard about leptospirosis, a high percentage of them had limited knowledge regarding the severity of the disease and its prevalence in the region. Our results suggest that public health interventions in these riverside communities should focus on educating the public on the multiple dimensions of leptospirosis in order to attain greater adherence to preventive practices instead of intending to change the perceptions or attitudes towards the disease, which did not have a significant influence. The key challenge lies in identifying effective strategies to reach the high risk group for leptospirosis here that is male fishermen, who spend most of the time in precarious campsites on the river islands. Leptospirosis is a zoonotic bacterial disease that has been recognized as a growing public health problem affecting mainly residents from slum settlements located in floodable areas. As such, it is considered a neglected disease that needs greater attention to reduce its global burden. A key step towards this purpose is to identify factors that influence the adherence to preventive practices regarding leptospirosis in endemic areas. We conducted a survey on residents of riverside settlements of the province of Santa Fe, an endemic area in Argentina, in order evaluate the knowledge, attitudes and practices regarding leptospirosis. Our results suggest that risky practices were performed mainly by men and that, contrary to our expectations, having a positive attitude towards leptospirosis does not appear to influence the likelihood of performing preventive practices, while greater knowledge about the disease does lead to safer practices. Public health officials should develop a comprehensive plan with diverse information, education and communication activities to promote a better understanding of the symptoms, treatment and prevention of leptospirosis by the various actors involved.