The Biodiversity and Bioindicators research group (BiBIO), based at the Natural Sciences Museum of Granollers, has coordinated four long-term faunal monitoring programmes based on citizen science over more than two decades in Catalonia (NE Spain). We summarize the historical progress of these programmes, describing their main conservation outputs, the challenges overcome, and future directions. The Catalan Butterfly Monitoring Scheme (CBMS) consists of a network of nearly 200 recording sites where butterfly populations have been monitored through visual censuses along transects for nearly three decades. This programme provides accurate temporal and spatial changes in the abundance of butterflies and relates them to different environmental factors (e.g., habitat and weather conditions). The Bat Monitoring Programme has progressively evolved to include passive acoustic monitoring protocols, as well as bat box-, underground- and river-bat surveys, and community ecological indices have been developed to monitor bat responses at assemblage level to both landscape and climatic changes. The Monitoring of common small mammals in Spain (SEMICE), a common small mammal monitoring programme with almost 80 active live-trapping stations, provides information to estimate population trends and has underlined the relevance of small mammals as both prey (of several predators) and predators (of insect forest pests). The Dormouse Monitoring Programme represents the first monitoring programme in Europe using specific nest boxes for the edible dormouse, providing information about biological and demographic data of the species at the southern limit of its distribution range. The combination and complementarity of these monitoring programmes provide crucial data to land managers to improve the understanding of conservation needs and develop efficient protection laws.

Plant–animal interactions play a crucial role in ecosystem functioning, especially through seed dispersal mechanisms. Understanding how small mammal populations respond to seed availability is essential for ecosystem management and biodiversity conservation, especially in the context of habitat loss and climate change. We conducted a 10-year study in mixed Mediterranean oak–beech forests to investigate the population dynamics of common small mammal species in response to seed availability. Our findings revealed distinct responses among species, influenced by life history traits, foraging behaviour, and diet. Wood mice (Apodemus sylvaticus) showed a rapid population increase with seed availability both in the same year of seed fall and the following year, suggesting a flexible foraging strategy and a dependence on arboreal seed producers. Yellow-necked mice (Apodemus flavicollis) revealed immediate population increases in response to seed availability in the autumn, probably because of their arboreal habits and preference for exploiting seeds prior to maturation. Bank voles (Clethrionomys glareolus) showed responses with population peaks in years following high seed availability, indicating a slower demographic response to resource abundance. Surprisingly, the greater white-toothed shrew (Crocidura russula) responded indirectly to seed availability in Mediterranean forests, suggesting complex interactions with seed-associated invertebrates or dependence on other variables not considered. Our findings highlight the importance of understanding how changes in seed availability influence the population ecology of small mammals, with significant implications for the conservation and management of Mediterranean forest ecosystems in the context of climate change and recurrent droughts. These results emphasise the need to consider species interactions, resource availability, and climate change in the conservation and management of evolving ecosystems.

This study investigated the effects of habitat structure and climatic variables on populations of bank voles (Clethrionomys glareolus), a northern species with adaptations to cooler climate, at the southern end of their range in Western Europe over a 16-year period. This is the first long-term analysis of its kind in this region. The study aims to understand how these variables influence the population dynamics and occupancy of bank voles. The results suggested that warmer years and extreme precipitation events lead to a reduction in bank vole abundance. Although changes in land use were minimal in the plots studied, changes in forest composition, particularly the expansion of coniferous forests at the expense of deciduous forests, were also related to lower bank vole abundance. Occupancy models, taking into account detectability, indicated stable occupancy in all regions. Our results suggest that climate change and habitat alterations, such as changes in forest composition, could pose threats to bank vole populations in these regions.

The main goal of this study was to analyze the reproductive patterns of edible dormouse (Glis glis) populations in the northeast of the Iberian Peninsula using an 18-year period of data obtained from nest boxes collected between 2004 and 2021. The average litter size in Catalonia (Spain) was 5.5 ± 1.60 (range: 2–9, n = 131), with litter sizes between 5 and 7 pups as the more frequent. The overall mean weight in pink, grey and open eyes pups was 4.8 g/pup, 11.7 g/pup and 23.6 g/pup, respectively. No differences in offspring weights between sexes were found in any of the three age groups. Maternal body weight was positively associated with mean pup weight, whereas no correlation between the weight of the mothers and litter size was found. The trade-off between offspring number and size was not detected at birth. Regarding litter size variation across the geographic gradient (and their climatic gradient associated) from the southernmost populations of the Iberian Peninsula located in Catalonia to the Pyrenees region in Andorra, no evidence to suggest that geographic variables affect litter size was found, discarding (1) an investment in larger litters to compensate shorter seasons related to higher altitudes or northern latitudes, and (2) variation in litter size related to weather changes (e.g., temperature and precipitation) along latitudinal and/or altitudinal gradients.

The Edible Dormouse (Glis glis) is a small arboreal mammal that lives in deciduous forests in much of Europe, the Iberian Peninsula being one of the southern limits of its distribution. Some studies have shown that this species uses the strategy of anticipatory reproduction, which means that it adapts its reproductive effort to seed production, such as beech mast and acorns, which varies greatly from year to year. The Edible Dormouse anticipates future seed availability of the coming autumn and modulates its reproductive effort, as beech mast and acorns are a crucial resource for the young to survive their first hibernation. This work aims to determine the correlations between annual variations in climate and seed production, and their effect on Edible Dormouse reproduction using 9 years of data (2012–2020) in two natural parks in Catalonia (Montseny and Montnegre-Corredor). These are located at the southernmost limit of the distribution of this species in the Iberian Peninsula. The results show that the productivity of Beech trees (Fagus sylvatica) is conditioned by local meteorological conditions and pollen availability, and that the acorn production by oak trees (Quercus sp.) is also affected by local meteorological conditions, but not by pollen availability. Additionally, breeding by the Edible Dormouse in Montseny has shown high synchrony with acorn production and that the presence of beech seeds increases the number of offspring per female. These results encourage us to conduct future studies to predict how Edible Dormouse populations will be impacted by climate change.

The Dormouse Project is a citizen science project that has been studying and surveying the Edible Dormouse populations of the Iberian Peninsula. The project started in 2004 at the Montnegre-Corredor Natural Park, because of the lack of studies in the Iberian Peninsula and the few existing records of this species in Catalonia. It is coordinated by the Natural Science Museum of Granollers and funded by the Catalan administration. This project aims to assess the distribution and population trends of the Edible Dormouse by the installation of special nest boxes along the Iberian Peninsula. Furthermore, it has an important dissemination and awareness-raising role, by conducting different informative sessions adapted to a broad audience. The web platform (www.dormice.org), created in 2020, is a tool that has facilitated citizen participation, together with the creation and consolidation of a network of collaborators within the Dormouse Project. It has helped to compile, store, and manage the data collected by citizen volunteers and interested scientific personnel. The project improves the quality and comparability of data collection by developing a standardized data collection framework. This will harmonise the collection of information between different volunteers and will make it easier to compare data. Nowadays, the platform is getting consolidated, and we are willing to expand its limits, as well as showing its potential as a shared platform within the regions of Edible Dormouse distribution.