THERYA

Social arenas in the open habitat: the social role of waterholes for saiga antelope

2024-01-08T12:54:50+00:00

In wild animals, specific locations may function as ‘social arenas’ playing a significant role in various aspects of intraspecific interactions. The emergence of such social arenas is assumed to be particularly important under conditions of low visibility and density of individuals typical for forest dwelling species. In the forest, open areas with a high probability of meeting conspecifics such as waterholes and mineral licks can favor socialization. The paucity of studies on the open-habitat species limits our understanding of whether forest habitat is an essential condition for the emergence of social arenas. Here we address this issue by investigating whether resource hotspots function as social arenas in a species adapted to open habitat. The social behaviour in groups of saiga antelopes (Saiga tatarica tatarica) was recorded at large permanent waterholes (serving also as mineral licks) and away from them in the steppe environment. The frequency and variety of social interactions between the group mates were compared with a special effort made to minimize the potential impact of other factors besides the location. Also the focal individuals, interacting or not interacting with conspecifics at the waterholes, were traced continuously to explore the duration of their visit at the waterhole area. Finally, we recorded the number of individuals in the groups entering and leaving the waterhole. Active social interactions between group members occurred more often and were more varied near the waterholes as compared to the areas away from them. The participation in social interactions influenced the duration of individual waterhole visits. Males that interacted with others shortly after arrival stayed significantly longer compared to those who did not. Females whose calves engaged in social interactions with age-mates spent more time at the waterholes than females whose calves did not. The comparison of mean group sizes showed that saigas left waterhole areas in larger groups than they entered them. Our findings, together with previous studies, suggest that resource hotspots can function as social arenas in mammals regardless of the habitat type (open or closed). The emergence of specific locations having particular social significance may be especially important for highly dispersed species with large home ranges. The results of the study emphasize the significance of large permanent waterholes and mineral licks used by many individuals year after year for the social behaviour of saiga antelopes.

Community of medium and large-sized mammals and functional diversity in a tropical rainforest of Southern México under different degrees of human pressure

2023-12-20T15:54:23+00:00

Functional diversity quantifies the distribution and range of functional traits of species that influence ecosystem processes. We evaluated the functional diversity of the medium and large-sized mammals in a tropical rainforest in Southern Mexico to determine which landscape characteristics associated with human activities affected the composition of mammal functional diversity and functional group abundances. We used camera-traps to document the diversity and composition of medium and large-sized mammals at four sites with different levels of protection and management. We estimated species richness, diversity, and functional diversity for each site, and compared these indices between sites to understand the effects of biodiversity loss in ecosystem dynamics and to detect ecological patterns driven by human perturbation. The density of human settlements was the main covariate related to low species richness and low abundance of large mammals with specialized diets and low population densities. Poaching and other human activities in forested areas near human settlements might have caused large herbivore and specialized carnivore populations to decrease, and populations of medium-sized rodent species to increase. Our results indicated that human perturbation in forested areas had also an impact at the functional level reducing the abundance of some functional groups, and this might have negative consequences for tropical rainforest functions in the long term. Effective management actions should be implemented in Protected Areas with a high density of human settlements nearby to prevent the decline of mammals’ functional groups and negative consequences for tropical rain forests’ ecological functions.

Non-volant mammals in the central Andes Yungas: the Pampa Hermosa National Sanctuary

2024-04-22T23:24:55+00:00

The Pampa Hermosa National Sanctuary (SNPH) is a Natural Protected Area (11,543 ha) that encompasses a large extension of central Yungas; however, despite its high priority status for the conservation of biodiversity, the non-volant mammals have been poorly documented. This study reports the non-volant mammals from the Yungas of the SNPH and its buffer zone, for the first time. We sampled four localities: Podocarpus (1,900 m), Los Cedros (1,600 m), Santa Isabel (1,450 m), and Nueva Italia (1,370 m), which encompass very humid premontane and montane forests. We used capture methods for small mammals; and direct and indirect records for medium and large-sized mammals. The capture effort was 6,860 traps-night (Sherman and Victor traps) and 490 buckets-night (pitfall traps). We recorded 31 native species: six marsupials, one cingulate, two primates, 18 rodents, two carnivores, and two artiodactyls, including the threatened species Lagothrix lagotricha tschudii and two endemic rodents. The most diverse orders were rodents and marsupials (77 %). The analysis of true diversity (^qD) showed that the montane forests of SNPH (1,600 to 1,900 m) had the highest values: Los Cedros (⁰D = 18.80) when order q = 0; and Podocarpus (¹D = 6.34; ²D = 4.99) when order q = 1, 2. The rank-abundance curves indicated the same taxa group (Hylaeamys yunganus, Akodon cf. A. aerosus, and species of Neacomys) as the most abundant at all localities. The species Marmosa (Micoureus) constantiae, Hylaeamys yunganus, Rhipidomys gardneri, Euryoryzomys nitidus, Oligoryzomys microtis, and Neacomys macedoruizi are the first records for the region of Junín. One species of Neacomys and another of Oecomys might be new species to science. A beta diversity analysis showed that the Yungas of SNPH are more similar to the Manu National Park (21 %) and the Tingo María National Park (20 %); highlighting that dissimilarity is high even between relatively close communities. Our study indicates that the SNPH allow connectivity with other nearby Yungas, especially for medium and large-sized mammals that need pristine and preserved forests. Nevertheless, the real diversity of the region is still far from being completely inventoried; additional evaluations with a diverse array of methods are needed toward that goal. In addition, the local and regional governments should get involved in conserving these fragile forests where the changes in land use may affect many key and endemic species.

Group structure and diurnal behavior in a large colony of Mimon cozumelae in Yucatán, México

2023-11-24T19:12:17+00:00

The Phyllostominae is a Neotropical subfamily of bats that include species considered sensitive to habitat disturbance, but that are the poorly known. The Cozumelan Golden Bat, Mimon cozumelae, is a rare phyllostomine that inhabits forests and semi-deciduous tropical forests from central México to western Colombia. This study describes for the first time, the social organization and diurnal behavior of M. cozumelae to provide basic information about the social relationships of this elusive species. We captured and marked individuals inhabiting a cave in Yucatán, México in 2020 and 2021. Observations were carried out filming its behavior inside the cave in two seasons, breeding (March-July) and non-breeding (August-January). We constructed an ethogram and classified the observed behaviors into states and events in each season. A total of 103 individuals (47 females and 56 males) of M. cozumelae were captured. The sex ratio was not different from 1:1. The size of the groups did not vary throughout the seasons. The most frequent behaviors performed by M. cozumelae were resting, followed by flight, self-grooming, wing extension, and social grooming. The group composition most common in both seasons was multi-male, ruling out the typical formation of harems in the breeding season for this species. Copulation and maternal grooming were recorded for the first time in the reproductive season. This bat exhibits social grooming, which in theoretical terms could categorize it as a species that forms societies. This study contributes updated information regarding group size and composition, and especially diurnal behavior of M. cozumelae. It is suggested that this work serves as a baseline to investigate its social systems (behavioral ecology) in depth, and when carrying out conservation plans for this species.

Corrigendum: The Phillips kangaroo rat (Dipodomys phillipsi): Population parameters

2023-10-23T18:35:10+00:00

Corrigendum
Montero-Bagatella, S. H., F. A. Cervantes, and A. González-Romero. 2023. Population parameters of the Phillips kangaroo rat (Dipodomys phillipsii). Therya 14:351-359.

Change in:
Figure 3. Average sex and age breakdowns of captured PhillipsÂ´ kangaroo rat (Dipodomys phillipsii) by season for 2012-2016, from Perote, Veracruz.