Hoarding food is an important strategy of rodents in desert environments characterized by unpredictable and poor food resource availability. In the Monte Desert, Prosopis produces abundant food, unevenly in time and space, in the form of pods and seeds. Sigmodontine rodents (Graomys griseoflavus,Akodon molinae, Eligmodontia typus and Calomys musculinus) use Prosopis propagules extensively, and they could be predators or dispersers depending on how they handle and where they leave the propagules. The objectives of this study were: (1) to know what rodent species transported propagules; (2) to evaluate what hoarding pattern was used by species that transport propagules (larder and scatterhoarding); and (3) to analyse in which condition were propagules left by the rodent species, both at the food source and in caches. Our results showed that all four species transported propagules, with G. griseoflavus and E. typus being the species that carried more seeds. Our study supported the evidence that food caching is common among species and that many species both larderhoard and scatterhoard food. Graomys griseoflavus and A. molinae, the largest species, larderhoarded more than did the smaller E. typus. These results uphold the hypothesis that larger species will show greater propensity to larderhoard than smaller species. Considering the interaction between seed-hoarding patterns and plants, E. typus was the species that could most improve germination because it scatterhoarded propagules and left seeds out of pods. In contrast, G. griseoflavus could have a negative impact on plant populations because this was the species that predated more seeds and larderhoarded a high percentage of them. The smallest C. musculinus was the species that transported propagules least, and left them as seeds inside pods or pod segments mainly at the food source, which makes seeds more vulnerable to predation.

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In arid and semiarid ecosystems, subterranean herbivorous rodents play an important role in determining the composition, function, and structure of plant communities. We hypothesized that in a high-altitude cold desert in the southern Puna region of Argentina, Ctenomys mendocinus (mendocino tuco-tuco), a subterranean herbivorous rodent, may increase dominance of the shrub Artemisia mendozana (sagebrush). We performed an observational study to assess factors affecting the abundance and fitness of A. mendozana in southern Puna, on sites co-inhabited and undisturbed by C. mendocinus. Density, biomass, plant height, number of fruits per plant, number of seeds, and seed size of A. mendozana were higher in mendocino tuco-tuco-disturbed areas. Because the abundance and reproductive ability of sagebrush increase in areas inhabited by mendocino tuco-tucos, C. mendocinus may function as an ecosystem engineer in southern Puna. We suggest further manipulative experimental studies be conducted to clarify the role of this subterranean rodent in this ecosystem.

In group‐living species, the development of agonistic interactions among conspecifics may be affected by socio‐ecological factors, such as size and composition of social group, and availability of nests and food. We analysed the importance of size and composition of social groups on agonistic interactions among males in the Southern mountain cavy (Microcavia australis). We made behavioural observations in four social groups of different size and composition. We recorded two types of agonistic interactions: agonistic displays and direct agonistic behaviours; both types increased in the breeding season. A social group composed of a high number of males was associated with high frequency of agonistic displays. Direct agonistic behaviours were also influenced by the interaction of season and number of males per social group and number of females per social group. Agonistic interactions were also recorded among males of different socials groups in the breeding season. Agonistic displays were most frequent among males of the same social group, whereas direct agonistic behaviours were most common among males of different social groups. These results suggest that social factors affect agonistic interactions among males of Southern mountain cavy and that in a conflict situation, males develop different strategies, such as increased frequency of agonistic behaviours in breeding season and intragroup cooperation for defence of oestrous females.