X Close Summary of the sampling season 2025 of the small mammal monitoring program SEMICE
2025 Season Summary
Once again, we're bringing you a summary of the project's results from last year! 2025 stands out as the year with the highest number of small mammals recorded in the history of the monitoring (for the first time since 2008, more than 3,000 individuals were registered in a single year, representing 16 different species). This was made possible by the 127 monitoring stations that were active throughout the year and the 57 collaborators who coordinated them. During the year, 99 collaborators also collected pellets and 32 participated in their identification. Thank you so much for making this newsletter possible once again!
Live Trapping
Since the project began in 2008, a total of 214 stations have been established, and 98 different people have been responsible for sampling. New monitoring stations are being established every year; 25 were inaugurated in 2025! But the most important thing is that, throughout the year, 15 new collaborators began their involvement in the monitoring. The goal will increasingly be to stabilize the active stations and open new ones only in areas where there are none yet.
During 2025, a thousand more individuals were recorded than in 2024 and 2,500 more than in 2023. Therefore, as the following graph indicates, comparing the overall abundance level with the three previous years (2022-2024), we can say that the results have been exceptional! On the other hand, we see that this increase in abundance has been reflected only in the three most common species, which have monopolized the sampling (more than 90% of the individuals captured): wood mouse (Apodemus sylvaticus), white-toothed shrew (Crocidura russula), and Algerian mouse (Mus spretus). Generally, the remaining species have been captured less frequently on average in 2025.
We often wonder which micromammal species would be good indicators of habitat quality, but the first step is to define the preferred habitat of each. Using the TAO (Closed-Open) index, which is already used for butterflies, we have been able to determine which of the common species tend to prefer open environments over more forested ones. In short, open Mediterranean spaces appear to support significantly better populations of Algerian mouse (Mus spretus) and white-toothed shrew (Crocidura russula) than forested environments. The red vole (Clethrionomys glareolus) and the yellow-necked mouse (Apodemus flavicollis) are typically found in forests along the Mediterranean coast, but the vole also thrives in the scree slopes (and other open areas) of mountainous regions. Finally, the wood mouse (Apodemus sylvaticus) is the most adaptable to all types of environments.
Owl pellets
The owl pellet data collection platform was created in 2022, coinciding with the start of the Atlas of Mammals of Catalonia, with the aim of collecting records of small mammals to help define species distribution. During these four years, in addition to incorporating information from previous years, results from 689 new locations throughout Spain have been entered, as the platform has also been used to complete the Atlas of Mammals of Spain.
Four species have clearly been captured more frequently than others over the past four years: the wood mouse (Apodemus sylvaticus, in yellow), the white-toothed shrew (Crocidura russula, in dark green), the Mediterranean vole (Microtus duodecimcostatus, in maroon), and the Algerian mouse (Mus spretus, in light blue). While the central and southern Iberian Peninsula is dominated by the latter two species, the wood mouse and the white-toothed shrew are more prevalent in the northernmost regions. Also noteworthy are the abundances of the common vole (Microtus arvalis, in ochre) in La Rioja and Castilla y León, as well as the Lusitanian vole (Microtus lusitanicus, in clay) in Asturias and Galicia. The situation in the Canary Islands is unique, as the house mouse (Mus musculus, in violet) is dominant there.
Publications and Works
By clicking here you will find the most recent works published using data collected by the SEMICE micromammal monitoring program.
Many thanks to everyone for making this possible and best of luck in the 2026 field campaigns!
Return
Contact | Legal notes | Credits | Subscripció al butlletí
