# Conservation of a threatened semi-aquatic mammal: Insights from a systematic review on the Pyrenean Desman (Galemys pyrenaicus)

Matthieu Sendral, Mário Santos

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## To cite this version:

Matthieu Sendral, Mário Santos. Conservation of a threatened semi-aquatic mammal: Insights from a systematic review on the Pyrenean Desman (Galemys pyrenaicus). Journal for Nature Conservation, 2025, 86, pp.126923. 10.1016/j.jnc.2025.126923. hal-05072015

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https://polytechnique.hal.science/hal-05072015v1

Submitted on 17 May 2025

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Review

Conservation of a threatened semi-aquatic mammal: Insights from a
systematic review on the Pyrenean Desman (Galemys pyrenaicus)

Matthieu Sendral<sup>a, *</sup>, Mário Santos<sup>b,c,d</sup>

ARTICLE INFO

Keywords:

Review
Pyrenean desman
Galemys pyrenaicus
Conservation
Threats
Ecological indicator

A B S T R A C T

This systematic review provides an overview of the existing knowledge to date on the Pyrenean desman (Galemys pyrenaicus), an endangered semi-aquatic mammal from the north of the Iberian Peninsula. Following the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 120 relevant publications and reports were analysed to synthesize the current state-of-the-art on the species' biology, ecology, threats and conservation. Key findings include the genetic structure of the population, its dietary habits, its habitat preferences, its seasonal movements, and new available monitoring methods. The underlying mechanisms of critical anthropogenic threats are further documented through targeted examples and figures concerning the decline of its populations. Based on these results, potential conservation actions to protect and recover Galemys pyrenaicus and its habitat are presented and discussed. Recommendations are finally provided regarding both technical and non-technical aspects of future conservation plans, including the focus of further research on this species.

1. Introduction

Species of freshwater ecosystems are among the most affected by
anthropogenic pressures worldwide (Almond et al., 2022; Reid et al.,
2019). A recent World Wildlife Foundation (WWF) report states that the
Living Planet Index for freshwater species has decreased by 83 % be-
tween 1970 and 2018 (Almond et al., 2022). However, these ecosystems
are crucial due to their diverse roles: apart from supporting numerous
species and assisting in nutrient cycling, they provide essential services
such as drinking water supply and flood regulation (Bullock & Acreman,
2003; Covich et al., 1999; Tomscha et al., 2017). They also help mitigate
climate change by storing carbon and moderating local temperatures,
and are crucial for fishing, tourism, and agriculture, thereby signifi-
cantly contributing to local economies (Almond et al., 2022; Declerck &
de Senerpont Domis, 2023; Tomscha et al., 2017). More specifically,
headwater streams, i.e. river stretches extending into the source areas of
watersheds, show specific physical, chemical and biotic characteristics,

making them crucial habitats for numerous species (Meyer et al., 2007).

Galemys pyrenaicus, also known as the Pyrenean desman or Iberian
desman, is a small semi-aquatic mammal found in the pristine, fast-
flowing, and well-oxygenated rivers of the mountainous areas of the
north of the Iberian Peninsula (Charbonnel, 2015; Nores & Salvador
Milla, 2017; Peyre, 1956). It is one of the most enigmatic species in
Southern Europe: identified in 1811 by Etienne Geoffroy Saint-Hilaire, it
has since remained largely cryptic due to its assumed nocturnal activity
and its elusive behaviour (Poduschka & Richard, 1986; Richard &
Viallard, 1969). Galemys pyrenaicus is known for its unique morpho-
logical characteristics, including its elongated snout, but also for its
adaptations to an aquatic lifestyle, such as its webbed hind feet and its
thermally insulating fur (Palmeirim & Hoffmann, 1983). It is a primarily
nocturnal mammal which spends most of its time foraging underwater
for aquatic macroinvertebrate larvae thanks to its highly specialized
sensory system, including Eimer's organs (Bauchot et al., 1973; Biffi
et al., 2017a, 2017b). Its niche, encompassing both aquatic and

<footnote><sup>a</sup> Ecole Polytechnique, Route de Saclay, 91128 Palaiseau, France</footnote>

<footnote><sup>b</sup> Laboratory of Fluvial and Terrestrial Ecology (LEFT), Innovation and Development Center and Department of Biology and Environment, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal</footnote>

<footnote><sup>c</sup> Research Group on Ecology and Conservation of Amazonian Biodiversity, Campus Itaituba, Federal Insti-tute of Education, Science and Technology of Para, Itaituba, PA, Brazil</footnote>

<footnote><sup>d</sup> Centre for the Research and Technology of Agroenvironmental and Biological Sciences, CITAB, Inov4Agro, Universidade de Trás-os-Montes e Alto Douro, UTAD, Quinta de Prados, 5000-801 Vila Real, Portugal</footnote>

<footnote>* Corresponding author.
E-mail address: matthieu.sendral@polytechnique.org (M. Sendral).</footnote>
terrestrial environments, supports its use as an ecological indicator of watersheds' integrity: its presence is usually considered indicative of high-quality headwaters (Biffi et al., 2020; Poduschka & Richard, 1986; Santamarina & Guitian, 1988). However, such a bioindicator is restricted to pristine, fast-flowing, and well-oxygenated rivers and cannot be used elsewhere.

Although the species has been known to be declining for over 60 years, major conservation plans were only introduced in 1994 in Portugal, 2002 in Andorra, and 2010 in France and Spain (Lim et al., 2021b). In 2021, the IUCN updated its status from “vulnerable” to “endangered” (Quaglietta, 2021), thereby highlighting the current dramatic alteration of habitats in its distribution range. The primary threats to this species stem from anthropogenic activities which degrade its habitat (Pedroso & Chora, 2014). Hydroelectric dams, water extraction for agriculture, and the construction of barriers across rivers disrupt flow regimes and may hinder the connectivity of streams, directly impacting habitat suitability (Aymerich & Gosalbez i Noguera, 2015; Escoda et al., 2018; Esaola et al., 2017, 2018b). Pollution from agriculture, industry, or even urbanization reduces the availability of its prey (Simal Ajo & Serdio Cosío, 2009), while climate change poses a significant long-term threat due to the induced altered precipitation patterns and subsequent effects on stream hydrology (Morueta-Holme et al., 2010). Finally, the fragmentation of riparian areas is another critical issue, as the increasing isolation of *Galemys pyrenaicus* populations restrains their dispersal abilities, reduces their genetic diversity and increases the risk of local extinctions (Castresana et al., 2013; Escoda et al., 2018; Gillet et al., 2016a).

Conservation efforts for *Galemys pyrenaicus* are critical not only to preserve this unique and endemic species but also to maintain the ecological and trophic balance of the freshwater ecosystems it inhabits (Biffi, 2017). This species is additionally considered an “umbrella” one as efforts to protect it serve a wide range of co-occurring species such as the European otter (*Lutra lutra*), the White-throated dipper (*Cinclus cinclus*), the Eurasian water shrew (*Neomys fodiens*) and several species of endemic invertebrates and plants (*Charbonnel, 2015*). The recent conservation campaigns have also turned this species into a symbol of the decline of Iberian and Pyrenean freshwater ecosystems, i.e. a “flagship” species whose image could be used to raise funds for conservation campaigns for riparian areas (Melero et al., 2014). In summary, *Galemys pyrenaicus* is a species of considerable ecological and scientific importance, whose protection is crucial in many regards. Given its current decline, conservation initiatives are urgent (Lim et al., 2021b).

Quick access to reliable information is needed by authorities and Non-Governmental Organizations for the Environment (NGOE) to produce more efficient conservation plans and actions (Némoz et al., 2011). Most studies conducted on this species over the past three decades have focused on specific aspects, such as genetics, habitat, and diet. The state-of-the-art has also significantly advanced over the past 15 years. In the scope of facilitating and integrating access to this information for more effective conservation, this review summarizes the available information on *Galemys pyrenaicus* to date (April 2024).

Specific objectives of this systematic review include answering the following research questions:

* Which elements of our current knowledge about *Galemys pyrenaicus*'s biology and ecology are important to the species' conservation?

* Which threats contribute to the current decline of its populations?

* Which measures should be implemented to prevent the species' decline and (possibly) enhance its conservation status?

Book chapters from the 20th century describe the species (Palmeirim & Hoffmann, 1983; Peyre, 1956; Richard & Viallard, 1969), and brief state-of-the-art studies have recently been carried out as part of conservation plans (Lim et al., 2021b), but only one review, in Spanish, has been conducted before on *Galemys pyrenaicus* (Nores & Salvador Milla, 2017). Our systematic review diverges from them by offering a detailed, comprehensive, up-to-date and methodical summary of the knowledge on the species, further discussing the implications for future conservation.

## 2. Material and methods

This systematic review was written using the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to gather the most relevant literature (Page et al., 2021). The PRISMA checklist includes 27 items to help authors report their systematic reviews and meta-analyses. It is designed to make these works more accurate, complete, transparent, standardized and reproducible (Page et al., 2021).

### 2.1. Retrieving the initial records

Four online academic databases were first chosen, based on the broadness of their search scopes: Scopus, Web of Science, PubMed and Google Scholar.

On April 8th, 2024, ten combinations of keywords were searched in titles, abstracts and keywords in Scopus, Web of Science and PubMed. Each combination was obtained by joining “*Galemys pyrenaicus*” or “Pyrenean desman” or “Iberian desman” and one of the following ten terms: “population”, “distribution”, “behavior” or “behaviour”, “water”, “feces” or “faeces”, “predator”, “habitat”, “dams”, “climate change”, “conservation”. In relation to the objectives of this review, the keywords were chosen to target publications dealing with threats to *Galemys pyrenaicus* and its conservation. No restrictions were imposed on the language or the publication date, and no further filters were applied. To broaden the search scope, these searches were repeated in the same academic search engines with keywords translated into Spanish, Portuguese and French. These languages were chosen based on the distribution of *Galemys pyrenaicus*. The list of keywords used in each language is available in Supplementary material n°1.

Due to the countless irrelevant results returned after applying the same protocol in Google Scholar (partly owing to the inability to target only titles, abstracts, and keywords), the keywords “*Galemys pyrenaicus*”, “Pyrenean desman” or “Iberian desman” were searched in titles only, with no additional keywords. This process was likewise repeated with keywords translated into Spanish, French and Portuguese. The exact search formulas entered in each search engine are available in Supplementary material n°2.

### 2.2. Sorting the records retrieved

Any duplicate in the previously retrieved records was excluded (Fig. 1). A search for the full version of each publication was achieved using the following process: when available, their DOI was looked up on the website doi.org. Otherwise, their title and the names of their authors were searched on Google Scholar. All publications not fully available (i.e. only titles or titles and abstracts were accessible) were not considered. The remaining publications were then read and assessed for eligibility based on two criteria: the records bearing no specific focus on *Galemys pyrenaicus* and those which were a pre-print version of another publication already included were set aside (Fig. 1).

No filter concerning the nature of publications was applied: both peer-reviewed articles and grey literature were included in the final selection. To cite the original source of each piece of information, some references quoted by the previously obtained publications were included in the final list of selected records (Fig. 1).

### 2.3. Analysing the publications

The final selection of publications was recorded in a database with the titles, dates, authors, DOI numbers when available, abstracts, and the search engines which returned the publications. This database is
<figure><img src="image_4.png" /><figcaption>Fig. 1. Flow chart of the PRISMA protocol used. Further information on each publication is available in Supplementary material n°3.</figcaption></figure>

available in Supplementary material n°3. It was further complemented by information on each record, namely their year of publication, their type (journal article, poster or conference paper, thesis, book chapter, or government report/plan), their locations (more specifically the countries of the populations/individuals studied) and the topics tackled. Bar plots were generated with R-Studio 2024.04.1 based on this information.

A list of publications dealing with each aspect of *Galemys pyrenaicus* (e.g. taxonomy, distribution area, ...; Fig. 2) was also established to write the systematic review. The publications allocated to each topic were analysed and compared to summarize the most relevant information concerning its biology, ecology, threats and conservation (Fig. 2). When dealing with contradictory information, more recent publications using more advanced techniques were deemed more reliable than old ones. Finally, while we tried to prioritize reproducibility and methodological clarity, insights based on expert observation were considered as valuable as peer-reviewed information. Likewise, information from all sources, including both grey literature and peer-reviewed journal articles, has been included in this systematic review as many unpublished works highlight rich conclusions. One person led the whole process while another reviewed it. No automation tool was used.

Finally, some of the information retrieved in this systematic review has been known for decades and is not directly relevant to the species' conservation. In relation to the focus of this work (i.e. threats and conservation of *Galemys pyrenaicus*), the results related to the following topics were not documented here but are available in *Supplementary material n°4*: taxonomy & distribution area, anatomy & adaptation, perceptive & cognitive abilities, reproduction, age & life expectancy, behaviour & activity.

# 3. Results

## 3.1. Results of articles search and compilation

In total, 229 publications were found (Fig. 1): 89 on Google Scholar, 61 on Scopus, 60 on Web of Science, and 19 on PubMed. 107 duplicates were first removed, which left 122 publications. Similarly, six publications could not be found. After careful reading for eligibility, 19 publications were set aside: 18 bore no specific focus on *Galemys pyrenaicus*

and one was the pre-print version of another publication already included. This process left 97 publications. Finally, 23 references cited by these 97 publications were added to the database to quote the original sources of each information mentioned in this review. The reference database is available in Supplementary material n°3. Fig. 3 shows the frequency distributions of the publications considered in terms of location, type, topic tackled and date of publication.

Almost half of the publications studied were from Spain (Fig. 3.a), which is consistent with *Galemys pyrenaicus's* distribution (cf. Supplementary material n°4 – "Taxonomy and distribution area"). Furthermore, about a quarter of studies were grey literature (Fig. 3.b). Such sources include reports, books, theses, and conference contributions: they often provide rich information and data unavailable in peer-reviewed studies. Among the topics tackled, threats and distribution & density dominated (Fig. 3.c), which is consistent with the search terms "conservation" and "distribution". Finally, the 2010 and 2020 decades are by far the ones with the highest number of publications on *Galemys pyrenaicus* (Fig. 3.d), which likely reflects the start of national plans and programs devoted to the conservation of *Galemys pyrenaicus* in several countries (Lim et al., 2021b).

## 3.2. Monitoring protocols

Most studies from the previous decade used a non-invasive method to detect the presence of *Galemys pyrenaicus*, relying on the collection of faeces assumed to belong to the species by trained observers. Their origin is further confirmed through DNA analysis to avoid any misidentification (Castresana et al., 2013; Hawlitschek et al., 2018; Ripa Lopez-Barrantes et al., 2024). Faeces are sampled downstream to upstream based on their visual appearance and smell (Charbonnel et al., 2017) on emerging rocks, roots and cavities along river transects of a given distance, assuming that the species defecates preferably in non-exposed riverbanks near locations of high-water flow (Carneiro et al., 2016). The survey of 250 m-long transects has been deemed sufficient (Aymerich & Gosálbez i Noguera, 2015), while studies from the French National Action Plan for *Galemys pyrenaicus* showed that faeces were detected within the first 200 m in 80% of the segments where the species was present (Charbonnel et al., 2017). Several DNA analysis techniques have been tested:
<figure><img src="image_5.png" /><figcaption>Fig. 2. Comprehensive overview diagram of the methodology used to conduct this systematic review.</figcaption></figure>

* Restriction Fragment Length Polymorphism PCR (RFLP-PCR) allows for the rapid discrimination of *Galemys pyrenaicus* from other species in collected faeces (Fernández-García & Vivas-Cedillo, 2017; Gillet et al., 2014; Ripa Lopez-Barrantes et al., 2024).

* Quantitative Polymerase Chain Reaction (qPCR) is used to characterize the diversity of parasites and microbiomes in the species' faeces (Ripa Lopez-Barrantes et al., 2023).

* Genome sequencing techniques such as Next-Generation Sequencing (NGS) or Sanger Sequencing allow for the identification of individuals based on faeces known to belong to *Galemys pyrenaicus*, for example, to assess the genetic structure of a population (Escoda et al., 2017; Igea et al., 2013; Gillet et al., 2016a).

* Metabarcoding is used to identify multiple species, especially *Galemys pyrenaicus* and its prey, in collected faeces by applying NGS techniques to the mitochondrial cytochrome oxidase 1 (COI) gene (Biffi et al., 2017b; Esnaola et al., 2018a; Gillet et al., 2015; González-Esteban et al., 2018; Hawlitschek et al., 2018). The species' diet can also be characterized using the same technique applied to all available genes (Biffi et al., 2017a).

All these methods allow for the identification of the species based on putative faeces and therefore contribute to updating its distribution area. However, they are unfit for estimating densities or minimal population sizes (Lim et al., 2020a). A sex-determination protocol has also been established, but it is more efficient with hair samples than faeces (Vidal et al., 2010).

The efficiency of detecting faeces is highly dependent on the local conditions as the faeces tend to be altered when exposed to sun, wind or water from rain or the river, thereby leading to a lower detection rate on the field or faeces too degraded to perform DNA analysis. The channel form and lithology, the tree cover, the season, the weather and the presence of a dam upstream are therefore major explanatory factors of the probability of detection (Charbonnel et al., 2015, 2022; Fernández-González et al., 2014b; Gillet et al., 2016b; González-Esteban et al., 2018; Nores et al., 1998). The training of the staff is likewise important to limit the observer's bias. Finally, this method is logistically cumbersome and costly in terms of time, people and money (Charbonnel, 2015;

Levy-Otheguy et al., 2024), while it is thought to be non-exhaustive (González-Esteban et al., 2018).

Alternatives to this costly method have therefore been proposed. First, DNA analysis can be bypassed for faeces in which *Galemys pyrenaicus*'s hairs found in the collected faeces are identified since these have distinctive features (Simal Ajo & Serdio Cosío, 2009). Second, the combination of spatial replicates with Markovian occupation models only slightly underestimates the occurrence probability (Charbonnel et al., 2014). Such an approach could therefore replace the traditional and more costly temporal replicates, at least in the less favourable and accessible transects and when the study's objectives allow it (e.g. for a quick assessment of occupancy across multiple sites but not for the long-term monitoring of a population) (Charbonnel et al., 2014). Furthermore, artificial shelters, also known as faeces tunnels or artificial latrines, are floating devices designed for *Galemys pyrenaicus* to rest and defecate, leaving behind faeces more easily identifiable (González-Esteban et al., 2018; Lacaze & Servière, 2019). Despite being difficult to install due to their weight, these gave significantly improved results compared to faeces sampling or live trapping in both Spanish and French Pyrenees, while also being less vulnerable to extreme weather conditions (González-Esteban et al., 2018; Lacaze & Servière, 2019; Levy-Otheguy et al., 2024). The detection of *Galemys pyrenaicus* using environmental DNA techniques (e.g. based on water samples which could contain traces of the species' DNA) has so far been unsuccessful (Steinmetz et al., 2018).

Finally, *Galemys pyrenaicus* can be trapped using various adapted nets with a downstream entrance, sometimes followed by the use of a radiotracking device to monitor it over time (Poncet et al., 2021). Individuals can also be tagged for mark-and-recapture studies (Richard & Viallard, 1969). As the species is mostly nocturnal (cf. Supplementary material n°4 – “Behaviour and activity”), the operation is conducted at night to optimise the chances of success. Winglet traps have been shown to offer the best efficiency, but simple ones are cheaper and easier to use (Poncet et al., 2021). Captures allow the monitoring of individuals over time, as well as the determination of the sex (Richard & Viallard, 1969) and approximate age (cf. Supplementary material n°4 – “Age and life expectancy”) (González-Esteban et al., 2002). Such information can then be used to estimate densities, minimal population sizes, accurate
<figure><img src="image_6.png" /><figcaption>c) Topics tackled</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>b) Types of publications</figcaption></figure>

<figure><img src="image_8.png" /><figcaption>d) Dates of publications</figcaption></figure>

<figure><img src="image_9.png" /><figcaption>Fig. 3. Distributions of the publications considered by a) country, b) type, c) topic, and d) date. Some publications cover several topics and countries.</figcaption></figure>

locations of resting sites and movements (Gillet et al., 2016b; Lim et al., 2020a). Furthermore, DNA samples can be collected on captured individuals to sequence their genomes using NGS techniques and assess populations' genetic structure (Gillet et al., 2016b; Querejeta et al., 2016) or connectivity (Escoda et al., 2017, 2018). Although both methods serve different objectives, captures have been proven to be more reliable than faeces collection for detecting the species (González-Esteban et al., 2003), though more recent studies could not confirm it (Poncet et al., 2021). However, this invasive method significantly disturbs individuals, can result in accidental deaths (Lim et al., 2020a; Poncet et al., 2021) and requires legal authorizations and training given the conservation status of this mammal (Ripa Lopez-Barrantes et al., 2024). The results documented in the following sections describing the

biology, ecology and threats to *Galemys pyrenaicus* have especially been obtained using these previously described monitoring protocols.

### 3.3. Biology and ecology

#### 3.3.1. Genome and genetic structure

*Galemys pyrenaicus* has a 1.83 Gb genome (Escoda & Castresana, 2021), with one of the lowest heterozygosity rates among mammals (Escoda et al., 2018, 2022; Escoda & Castresana, 2021; Gillet et al., 2016a; Querejeta et al., 2016). This stems from abnormally high inbreeding coefficients, for example evidenced in the Spanish Pyrenees (Escoda et al., 2017, 2022), as a consequence of the fragmentation of its habitat (Castresana et al., 2013; Escoda et al., 2018; Gillet et al., 2016a)
or of the relatively recent colonization of certain areas such as the Pyrenees (Igea et al., 2013). However, a heterozygosity excess in two multigene families was discovered in six individuals from various areas of its distribution range, showing that genetic diversity tends to be more strongly preserved in functionally critical regions (Escoda & Castresana, 2021).

Despite its limited distribution area (cf. Supplementary material n°4 – “Taxonomy and distribution area”), the species has geographically and genetically distinct lineages (Querejeta et al., 2017). The main lineages have emerged due to past isolation in glacial refugia during the Middle Pleistocene, followed by a postglacial colonization process possibly using a more extensive fluvial network partly disappeared since, thereby triggering geographic isolation and genetic divergence over time (Castresana et al., 2013; Igea et al., 2013). This structure is reflected in five distinct clades occupying different geographic areas: the Pyrenees, Cantabrian Mountains, Iberian System, Central System, and northwest of the Iberian Peninsula (including Galicia, northern Portugal, and the Montes de León) (Querejeta et al., 2016). Sequencing polymorphic microsatellite DNA portions, Gillet et al. (2016a) likewise evidenced three distinct genetic clusters in the French Pyrenees, dating back only 200 years ago.

On large time and space scales, watershed divides seem not to be an unsurmountable barrier for *Galemys pyrenaicus*, as effects of overland dispersal have been identified in Spain (Castresana et al., 2013; Querejeta et al., 2017). In relation to the aquatic requirements of the species, dispersal through rivers has significant effects on its genetic clusters at smaller scales (Querejeta et al., 2017): populations from disconnected (different watersheds) but close rivers usually have very few relationships (Escoda et al., 2017). The genetic subdivision is therefore also present at smaller scales: local studies in different areas have identified dozens of interconnected nuclei of variable sizes (Casadesús et al., 2001; Gillet et al., 2016a; Tarrafeta Calvo et al., 2015, 2019) separated by watershed divides or artificial barriers such as dams (Escoda et al., 2018).

### 3.3.2. Diet

*Galemys pyrenaicus* has high energy needs: it has been reported to eat the equivalent of its body mass on a daily basis in captivity (cf. Supplementary material n°4 – “Behaviour and activity”) (Richard, 1973). It is an insectivore semi-aquatic forager (Palmeirim & Hoffmann, 1983) with a rather highly diverse diet: 194 distinct genera were identified in 184 *Galemys pyrenaicus*'s faeces collected in the French Pyrenees, although this figure includes coprophagous invertebrates, parasites and soil microfauna unlikely to be direct prey (Biffi et al., 2017a). It feeds mostly on abundant and energetically profitable benthos macro-invertebrates larvae, specifically those of Trichoptera, Ephemeroptera, Plecoptera, and Diptera, but also Coleoptera, Amphipoda or Hemiptera (Biffi et al., 2017a, 2017b; Castién & Gosálbez, 1994; Esnaola et al., 2017; Santamarina & Guitian, 1988). Strictly terrestrial prey is also anecdotally found in its faeces, but it is still unknown whether they are actively hunted by *Galemys pyrenaicus* or opportunistically found on the banks or underwater after drowning (Biffi et al., 2017b). Finally, some individuals in semi-captivity were observed attacking, killing and consuming small vertebrates such as a trout (*Salmo trutta*) and an Iberian frog juvenile (*Rana iberica*), but such a behaviour probably happens rarely in natural conditions given the mobility of these prey and the limited perception abilities of *Galemys pyrenaicus* (cf. Supplementary material n°4 – “Perceptive and cognitive abilities”) (Quaglietta & Beja, 2018).

The proportion of each prey in its diet varies depending on the location of the study. Most publications therefore agree on a rather plastic and generalist foraging behaviour, the most frequent taxa often being the most consumed (Biffi et al., 2017a, 2017b). However, *Galemys pyrenaicus* operates a slight active taxa selection of its prey depending on the season (Biffi et al., 2017a; Santamarina, 1993). From a biological perspective, a clear preference for prey living in riffles and boulder

substrate has been shown, along with a positive selection of the ones with larger size and living in the water column or the litter (Esnaola et al., 2023). *Galemys pyrenaicus* also appears to favour taxa with high body flexibility, a good ability to manoeuvre in fast-flowing water, low mobility, no hard shell, and living exposed to the flow or clustered in groups (Esnaola et al., 2021, 2023). Such results would point at a specialized rheophilic predator behaviour, instead of a more generalist one as previously stated (Esnaola et al., 2023).

### 3.3.3. Other biotic interactions

In addition to the white-throated dipper (*Cinclus cinclus*), the Eurasian water shrew (*Neomys fodiens*) has been identified as a main trophic competitor of *Galemys pyrenaicus*, with a low but significant dietary overlap (Biffi et al., 2017a; Castién & Gosálbez, 1999; López-de-Sancha et al., 2022). However, in the French Pyrenees, both species favour rather different prey (aquatic rheophilic for *Galemys pyrenaicus*, terrestrial for *Neomys fodiens*) and seem to use distinct microhabitats (riffles for *Galemys pyrenaicus*, pools for *Neomys fodiens*), even though both species are often found in the same rivers (Biffi, 2017; Biffi et al., 2017a). A significant niche overlap has also been observed with the European eel (*Anguilla anguilla*) in a stream in northwest Spain, but this finding likely reflects local conditions and is not generalizable given the respective ecological requirements of both species (Santamarina, 1993).

*Galemys pyrenaicus* is an easy prey for bigger predators due to its poor perception abilities (cf. Supplementary material n°4 – “Perceptive and cognitive abilities”) (Richard, 1973). It is part of the diet of the European otter (*Lutra lutra*), although it is not its main prey (*Callejo & Delibes, 2008; Fernández López et al., 2014*). The recent recovery of European otters in the Iberian Peninsula does not explain the recent population decline undergone by *Galemys pyrenaicus* alone (Biffi, 2017), but future climate and land use changes will likely increase habitat overlap between both species, which would expose the species to higher predation risks (Russo et al., 2023). The American mink (*Neogale vison*) also significantly predates it in France, Spain, and more recently Northern Portugal (Fernández-García, 2024; Kauhala, 1996). *Galemys pyrenaicus* was finally observed to be a prey of pikes (*Esox lucius*), domestic cats (*Felis catus*) and dogs (*Canis lupus familiaris*), and a few major birds including white storks (*Ciconia ciconia*), owls (*Strix aluco & Tyto alba*), buzzards (*Buteo buteo*), and herons (*Ardea cinerea & Nycticorax nycticorax*) (Hernández, 1988; Nores & Salvador Milla, 2017).

Many macroinvertebrates which *Galemys pyrenaicus* feeds on can serve as intermediate hosts for parasitic nematodes and trematodes such as *Omphalometra flexuosa*, *Maritrema pyrenaica*, *Mathovius galemydis*, *Aonchotheca galemydis*, and *Paracuaria hispanica* (Alvarez et al., 1994; Nores & Salvador Milla, 2017; Ripa Lopez-Barrantes et al., 2023). Other infectious species have also been found in *Galemys pyrenaicus*: Crypto-sporidium spp., Eimeria spp., Salmonella spp., Staphylococcus spp. and Leptospira spp. (Ripa Lopez-Barrantes et al., 2023). While these taxa target its digestive system, other parasites infest its fur, such as *Eadiea desmanae*, *Lynxacarus dubinini* and *Oryctoxenus galemys* (Nores & Salvador Milla, 2017). However, the full extent of *Galemys pyrenaicus*'s parasite fauna has likely not yet been fully identified.

### 3.3.4. Habitat

*Galemys pyrenaicus* usually occupies steeply sloping, shallow, and rocky mountain streams (García & Mateos, 2007). These rivers are clear and cold and present a high oxygen rate but a low nutrient content: they are usually characterized as “trout areas” (Peyre, 1956). The water flow rate must be sufficient to remain uninterrupted (Peyre, 1956), but overly strong currents are also avoided: Charbonnel (2015) evidenced an optimum of 3 m³/s and a maximum limit of 30 m³/s in the French Pyrenees. It therefore negatively selects very narrow watercourses due to their unsuitability in summer, but also those too wide and deep (Nores et al., 1992; Simal Ajo & Serdio Cosío, 2009). It has also anecdotally been found in high-altitude lakes, artificial canals (Bertrand & Didier, 2008; Némoz & Baran, 2019) and underground streams in the French Pyrenees (García &
Mateos, 2007). However, it has never been captured outside a stream (Castién & Gosálbez, 1999), although recent genetic studies in Spain and Portugal showed that overland dispersal movements likely occurred (Escoda et al., 2017; Querejeta et al., 2017).

Galemys pyrenaicus has been detected at 23 m above sea level near Urrugne in the Western Pyrenees, and at 2,809 m near the Pic d'Aret in the Central Pyrenees (Lim et al., 2021b; Ministère de la Transition Ecologique et Solidaire, 2018; Simal Ajo & Serdio Cosío, 2009). Elevation does not appear to be a key variable for its distribution, although it is mainly found in mountain streams which present higher slopes and precipitation (Simal Ajo & Serdio Cosío, 2009). Atlantic-oriented hill-sides are often more suitable to Galemys pyrenaicus than Mediterranean-oriented ones, with less fragmented and larger distributions due to more regular precipitations (Agirre-Mendi, 2004; Casadesús et al., 2001). The number of tributaries also influences habitat selection, as these areas serve as refuges when the main watercourse is disturbed (Charbonnel et al., 2015; Conservación de la Naturaleza y Espacios Naturales de Extremadura, 2018; Fernández-González et al., 2014a). In relation to shelter and prey availability, Galemys pyrenaicus favours stretches including abundant emergent items and a greater percentage of substrate heterogeneity according to studies in the French Pyrenees and Portugal (Carneiro et al., 2016; Charbonnel, 2015). It is therefore mainly found in magmatic and metamorphic terrains usually including pebbles and boulders, rather than sedimentary ones with silt and sand (Charbonnel, 2015; Simal Ajo & Serdio Cosío, 2009).

Concerning its microhabitat selection, Galemys pyrenaicus favours rifles over slow habitats such as runs or pools according to studies in the Pyrenees (Biffi, 2017; Esnaola et al., 2017, 2021). Such a preference is believed to be related to the higher abundance of macroinvertebrate larvae in fast-flowing waters due to lower turbidity, higher oxygenation and higher food particle concentration (Biffi et al., 2016; Carneiro et al., 2016; Charbonnel et al., 2015; Esnaola et al., 2018b). However, recent work highlighted that such a selection is a consequence of its need for substrate heterogeneity and of buoyancy mechanical constraints (“the ambience”) rather than of prey availability (“the menu”) (Esnaola et al., 2021).

The rivers occupied by Galemys pyrenaicus are typically covered by riparian vegetation. Trees are believed to play a role in the food chain (fallen leaves feed the benthos larvae while roots mitigate pollution) and in the species' protection (branches participate in the closure of the environment, and roots stabilize the banks and offer shelter areas) (Conservación de la Naturaleza y Espacios Naturales de Extremadura, 2018). However, such an influence has not been proven to date, and it could hide a higher detectability of faeces in rivers covered with dense riparian vegetation and protected from rain.

### 3.3.5. Territory

Galemys pyrenaicus typically occupies natural or artificial cavities formed by rocks or roots for its nests, on average 65 cm away from the riverbank in the Spanish Pyrenees (Melero et al., 2012). It does not dig burrows but can expand with its snout pre-existing cavities such as ones built by other species (Richard & Viallard, 1969). The nest consists of a usually submerged or semi-submerged entry, a long upward-sloping corridor, and a spherical chamber which includes moss, branches, and grass (Melero et al., 2012; Nores & Salvador Milla, 2017; Stone, 1987a). Stone (1987a) reported a chamber diameter of approximately 15 cm, which appears narrow for a species approximately 25 cm long. Further studies are thus needed to confirm this observation.

Resting sites are, on average, separated by 250 m, and are neither exclusive nor permanent for any individual according to a study in the Spanish Pyrenees (cf. Supplementary material n°4 – “Behaviour and activity”) (Melero et al., 2012). Depending on the stream, densities from 1 to 9 individuals/km are reached, with an average of about 4 to 5 individuals/km (Chora, 2001; Lim et al., 2021a; Nores et al., 1998). Home range has been observed to extend from 180 m to 830 m, with an average of 250 to 520 m (Lim et al., 2022; Melero et al., 2012, 2014; Pedroso & Chora, 2014; Stone, 1987b). Such figures were obtained by

radiotracking individuals and therefore depend on the duration of the study and the local context (Stone, 1987b). Part of the home range is sometimes shared with other conspecifics (Melero et al., 2012; Richard & Viallard, 1969).

Galemys pyrenaicus can finally travel long distances: movements of up to 2.3 km were radiotracked in the Spanish Pyrenees (Melero et al., 2012, 2014), while faeces from the same individual were found 17.8 km apart within a year in the French Pyrenees, probably induced by hydraulic variations due to maintenance operations on an upstream dam (Gillet et al., 2016b). Its movements could also be seasonal: a major decrease of faeces occurrences in summer compared to the end of the rainy season was found in the Tâmega watershed in Portugal, indicating that Galemys pyrenaicus could be moving from small tributaries to bigger watercourses searching for suitable conditions (Fernández-González et al., 2014a).

### 3.4. Threats

Local studies have pointed out for several decades that Galemys pyrenaicus populations are undergoing substantial decline in all areas of its range, as well as a major range contraction and habitat fragmentation (Charbonnel, 2015; Charbonnel et al., 2016; Gillet et al., 2016a; Gisbert & García-Perea, 2014; López-de-Sancha et al., 2022; Némoz et al., 2011; Quaglietta et al., 2018). On a large spatial scale, the IUCN red list reckons that “an overall population decline of 50 % over the last decade is plausible” (Quaglietta, 2021). More precisely, across Portugal, the species has suffered a strong range contraction since 1993 (Pedroso & Chora, 2014). It has massively disappeared from the main rivers in the Tua and Sabor watersheds, now persisting only in headwater streams of mountainous areas, with an estimated extinction rate of 63.5 % between 1993–1996 and 2014–2015 (Quaglietta et al., 2018). In the French Pyrenees, it could no longer be detected in 2011–2013 at 29 % of the sites where it had previously been observed between 1985 and 1992 (Charbonnel et al., 2016). Similarly, in the Spanish Pyrenees within the Parc Natural de l'Alt Pirineu, its presence declined by 12.5 % between 2000 and 2013–2014 (Aymerich & Gosàlbez i Noguera, 2015). In the Central System, recent surveys have failed to detect Galemys pyrenaicus in historically occupied sites (Igea et al., 2013), and its local distribution range has contracted by an estimated 97 % reduction between 1838 and 2011 (Gisbert & García-Perea, 2014).

The IUCN states six loss drivers, all related to human activity: pollution, climate change & severe weather, natural system modifications, human intrusions and disturbances, biological resource use, and invasive and other problematic species, and genes & diseases (Quaglietta, 2021).

#### 3.4.1. Pollution

Galemys pyrenaicus tends to avoid polluted waters as the larvae it feeds on are very sensitive to variations in acidity, temperature, oxygenation, or opacity (Esnaola et al., 2017; Simal Ajo & Serdio Cosío, 2009). It might also be directly impacted by certain types of water pollution: it reacts to low-quality water by spending more time grooming (Richard, 1973). More specifically, a tolerance to moderate organic pollution but a possible sensitivity to other types of water alteration such as acidification were reported (Santamarina, 1995). A preference for low ammonium concentrations, limited overall ion contents, and low conductivity was later highlighted (Biffi et al., 2020).

Overall, pollution threats are a major issue to the species as these can extend dozens of kilometres downstream (Lim et al., 2020b). For example, manure discharges and overflows from sewage treatment plants raise significant conservation problems in Cantabria, Spain (Simal Ajo & Serdio Cosío, 2009). This is also supported by the species' abnormal decline on the river Rébenty in France following a contamination incident (Lim et al., 2021a). Galemys pyrenaicus is therefore considered an excellent biological indicator of mountain streams' water quality (Poduschka & Richard, 1986; Santamarina & Guitian, 1988).
### 3.4.2. Artificial hydraulic structures

The term “hydraulic structures” refers to various types of human-made constructions designed to manage water flow in streams and rivers: dams and reservoirs (for hydroelectricity or irrigation purposes), weirs, water uptakes, diversion canals, watermills, fishponds, dykes and flood protection systems.

Dams, water uptakes and canals are first responsible for artificial variations of water flow downstream (Aymerich & Gosàlbez i Noguera, 2015), especially during operations of maintenance or dredging. Minor bed and hydrology-related variables have a major impact on *Galemys pyrenaicus*'s distribution (Biffi et al., 2020; Charbonnel et al., 2015): water diversions reducing discharge and flow velocity are a major threat to the species as they reduce the area of riffles which are essential foraging habitats (Esnaola et al., 2017, 2018b; Némoz & Baran, 2019). Macroinvertebrates also suffer from these flow alterations, which could increase the competition for this resource and further threaten *Galemys pyrenaicus* populations (López-de-Sancha et al., 2022). It is also believed that the legally required minimal environmental water flows at dams' output are not suited to *Galemys pyrenaicus*'s needs as these are often lower than summer natural low-flow conditions, thereby affecting food availability (Esnaola et al., 2021; Némoz & Baran, 2019). As evidenced in the Spanish Pyrenees, water quality can also be altered downstream, especially during emptying operations which increase turbidity and trigger massive re-suspensions of sediments or chemicals detrimental to macroinvertebrates (Aymerich & Gosàlbez i Noguera, 2015).

Moreover, *Galemys pyrenaicus* tends to avoid the deep lakes formed by artificial river barriers as these are unfavourable habitats for its prey (Tarrafeta Calvo et al., 2019). Therefore, tributaries which were once connected by a river are now separated by a barrier that hinders connectivity between population units (Tarrafeta Calvo et al., 2019). Dams and weirs could thus become a physical barrier to these animals, despite their climbing abilities (cf. Supplementary material n°4 – “Anatomy and adaptation”) (Tarrafeta Calvo et al., 2015, 2019). Genetic studies in the Spanish Pyrenees recently claimed that this loss of connectivity can induce an accelerated loss of fitness and extinction vortex for populations (Escoda et al., 2018, 2022).

The information available to date on the exact impact of these hydraulic structures is limited. Sections located upstream of such constructions are generally more favourable to the species than those downstream (Lim et al., 2021a; Nores et al., 1998), but this could hide other factors (e.g. slope or substrate heterogeneity). In the French Pyrenees, changes in resting sites, home ranges and activity patterns were observed in the context of dam-related hydraulic variations (Lim et al., 2022), while two long-distance movements were recorded simultaneously with dam repair works (Gillet et al., 2016b). More than the barrier itself, the hydraulic management of water flow seems to be crucial: the liberalization of the electricity market, adding a layer of unpredictability to the output flow of hydroelectric plants, is suspected to have caused the extinction of *Galemys pyrenaicus* from the upstream section of the River Noguera-de-Cardós in the Spanish Pyrenees, a stretch in which it had survived for decades with the same dams before (Aymerich & Gosàlbez i Noguera, 2015).

Finally, the extent to which *Galemys pyrenaicus* can cross water obstacles is currently unknown: an individual has been observed climbing a 10 m high dam on the River Aude in France (Charbonnel, 2015), and some individuals would have crossed over hydroelectric plants during long-distance movements (Gillet et al., 2016b), but mortality cases have also been found down these barriers in the French Pyrenees (Charbonnel, 2015). Whatever the mechanism, the impact of hydraulic structures likely depends on the local context: in the Zamora province, Spain, a study of six artificial river obstacles over 3.5 m revealed that only one significantly impeded genetic flow between individuals (Escoda et al., 2018). However, this effect was still less pronounced than that of natural watershed divides (Escoda et al., 2018).

### 3.4.3. Climate change

Climate change translates both in modifications of air temperature and precipitation patterns (IPCC, 2023). Both variables could severely impact *Galemys pyrenaicus* (Quaglietta et al., 2018). Indeed, at a large scale (but not at a fine one), mean summer temperature and water balance are predominant factors over human footprint ones for its distribution in Spain (Morueta-Holme et al., 2010), while hydrological and climatic variables have been deemed crucial in the French Pyrenees (Charbonnel et al., 2016, 2022). More specifically, precipitation variables appear to play a predominant role compared to temperature ones in the species' distribution in France (Williams et al., 2012), while both have critical importance in Spain (Morueta-Holme et al., 2010).

The flow rate is a critical condition when it comes to forming riffles, *Galemys pyrenaicus*'s preferred microhabitat (Esnaola et al., 2017, 2018b), while the number of tributaries plays a sheltering role when the main watercourse is disturbed (Charbonnel et al., 2015). Moreover, water temperature and acidity impact communities of macro-invertebrates (Biffi, 2017). Therefore, the increase in the number of dry years in the Iberian Peninsula could be one of the reasons for *Galemys pyrenaicus*'s decline, especially as the range shifts are restricted due to its fragmented habitat (Casadesús et al., 2001; Gisbert & García-Perea, 2014). Such a trend is likely to intensify with more severe and prolonged droughts and shorter rainy seasons over its distribution area (cf. Supplementary material n°4 – “Taxonomy and distribution area”) (Lima et al., 2023; Schleussner et al., 2020). On the contrary, floods do not appear to be detrimental to *Galemys pyrenaicus*: no decline was observed following the massive floods of 2013 in the French Pyrenees (Aymerich & Gosàlbez i Noguera, 2015).

The exact mechanisms through which climate change impacts *Galemys pyrenaicus*'s distribution are still discussed to date. A significant habitat loss by 2050 in relation to variables such as shifts in day-to-night temperature oscillations and temperature seasonality was recently predicted across Spain and Portugal (Russo et al., 2023), which could be related to a higher energy demand for thermoregulation in a context of climate change.

### 3.4.4. Other anthropogenic threats

Being a semi-aquatic species, the occupation of surrounding terrestrial areas seems to matter little when it comes to local habitat selection, and *Galemys pyrenaicus* appears to be tolerant to anthropogenic alterations to the floodplain, as long as the riverbanks provide shelter opportunities (Biffi et al., 2016; Charbonnel, 2015; Charbonnel et al., 2016; Peyre, 1956). However, all riverbed construction activities could potentially have significant detrimental impacts on the species according to Lim et al. (2020b). The alteration of riverbanks can damage essential riparian vegetation or shelters, which are crucial to its resting and reproduction (Carneiro et al., 2016; Lim et al., 2020b). Gravel and sand extractions can lead to contamination and likewise eliminate potential nests for the species (Pedroso & Chora, 2014). Construction equipment can crush individuals or disturb them with noise and vibrations, while pipes and other equipment might trap them (Lim et al., 2020b). Finally, direct modifications of the riverbed, whether intentional or not, might destroy its foraging habitats, deteriorate its food resources and trigger a temporary or permanent loss of connectivity (Lim et al., 2020b).

Furthermore, the presence of humans within riverbeds, for example for recreational activities such as canyoning or other aquatic sports causing trampling, degrades *Galemys pyrenaicus*'s habitat structure and is detrimental to benthos larvae (Biffi, 2017). Likewise, the crossing of rivers by cattle or vehicles such as tractors releases sediments and fine particles in the water, thereby affecting its suitability to this mammal (Biffi et al., 2020).

Fishing can also be a threat to the species: poisons, nets and explosive fishing methods can lead to its accidental death, while some direct persecution, by fishermen ill-informed about its diet, have been reported in Portugal (Carneiro et al., 2016; Pedroso & Chora, 2014). Water
uptakes for irrigation without grids, abandoned nets, measuring strings or even plastic bottles can also be deadly traps for *Galemys pyrenaicus* (Lim et al., 2021b).

Invasive species might additionally play a role in *Galemys pyrenaicus*'s decline: the American mink directly predates it across its whole distribution range (cf. Supplementary material n°4 – “Taxonomy and distribution area”) (Gisbert & García-Perea, 2014; Kauhala, 1996; Pedroso & Chora, 2014), while Tua and Sabor watersheds in Portugal have been increasingly invaded by two exotic crayfish, *Procambarus clarkii* and *Pacifastacus leniusculus*, which may decrease habitat suitability for *Galemys pyrenaicus* by affecting macroinvertebrate populations (Quaglietta et al., 2018). Roaming cats have also been reported to be a threat to *Galemys pyrenaicus* in France (Lim et al., 2021b). However, biotic interactions with competitors such as *Cinclus cinclus* and *Neomys fodiens* do not appear to be key factors to explain the presence or absence of *Galemys pyrenaicus* in French Pyrenees streams (Biffi et al., 2020). Finally, the practice of capturing and killing *Galemys pyrenaicus* for research purposes was documented in 1986, with over 70 dried skins found in a laboratory in Madrid (Poduschka & Richard, 1986), but the methods for studying this species have since evolved and today consider ethics and animal welfare. However, faeces collection and radiotelemetry-based monitoring still cause trampling pressure (Biffi, 2017).

## 3.5. Conservation

### 3.5.1. Status and laws

*Galemys pyrenaicus* has been listed as “endangered” by the IUCN since 2021 (Quaglietta, 2021). It is classified at national levels as “vulnerable” in France and Spain, as “endangered” in Portugal and as “critically endangered” in Andorra. It is also considered “in critical danger of extinction” in the Spanish Central System (Braz et al., 2023; Lim et al., 2021b).

At a European scale, *Galemys pyrenaicus* is included in Appendix II of the Bern Convention on the conservation of wildlife and natural habitats, and in Appendices II and IV of the European Union's Habitats Directive 92/43/EEC of 21 May 1992. As such, member states must prohibit its killing, any deliberate damage to its resting site or disturbance during its reproduction period, and any deterioration of its habitat. It is therefore protected by France (“article L.411-1 du code de l'Environnement” and “arreté ministeriel du 2 Avril 2007”), Spain (“real decreto 439/1990, de 27 de Marzo”), Portugal (“decreto-lei n°140/99, de 24 de Abril” and “decreto-lei n°316/89, de 22 Setembro”), and Andorra (“decret del 28/02/2001 – BOPA num. 23 any 13”) (Lim et al., 2021b).

### 3.5.2. Current and past conservation plans

In France, three main programs have been dedicated to the conservation of *Galemys pyrenaicus*. The first national action plan for *Galemys pyrenaicus* (PNAD I, 2010–2015) focused on improving knowledge of the species, developing study tools, and assessing the impact of water-related human activities (Némoz et al., 2011). The LIFE + Desman project (LIFE13NAT/FR/000092, 2014–2020) extended this work through a more operational phase across 11 Natura 2000 sites, focusing on evaluating the species' distribution, taking it into account when planning hydraulic management facilities, and protecting/restoring its habitat (Lim et al., 2021b). Currently, the second national action plan (PNAD II, 2021–2030) aims to further enhance knowledge about *Galemys pyrenaicus*, monitor key areas and populations, raise awareness among the public and industrial stakeholders, and foster international collaboration with Spain and Andorra (Lim et al., 2021b).

In Spain, many studies have been conducted on *Galemys pyrenaicus* since the end of the 90s (González-Esteban et al., 2018; Melero et al., 2012, 2014; Tarrafeta Calvo et al., 2015, 2019). Conservation actions have been initiated at regional scales (Conservación de la Naturaleza y Espacios Naturales de Extremadura, 2018), along with the implementation of “Important Areas for Mammals” (ZIM) (Nores & Salvador Milla,

2017). The LIFE + Margal Ulla (LIFE09NAT/ES/000514, 2010–2015) aimed at restoring populations of freshwater pearl mussels (*Margaritifera margaritifera*) and *Galemys pyrenaicus* in the Ulla watershed (Fernández-González et al., 2014b). Likewise, the LIFE + Desmania project (LIFE11-NAT/ES/691, 2012–2018) focused on 33 Natura 2000 sites to explore species' distribution and population trends, expand knowledge, improve riparian areas and water flow management, manage the impact of the American mink, and raise public awareness (Conservación de la Naturaleza y Espacios Naturales de Extremadura, 2018).

In Portugal, from 1994 to 1997, early studies on the species have been conducted by the Instituto da Conservação da Natureza (ICN), particularly under the LIFE Natural Habitats and Flora Species of Portugal program (LIFE94NAT/P/001043) (Pedroso & Chora, 2014; Queiroz, 1996), resulting in a critical reference document which laid the foundations of future conservation initiatives concerning *Galemys pyrenaicus* (Queiroz et al., 1998). Following this program, several targeted studies were conducted to update its distribution area and investigate the impact of hydroelectric dams (Chora, 2001). An action plan was later developed in 2014 by the ICN and integrated into Portuguese legislation, but few actions have been taken since then to mitigate its threats, apart from local compensation measures related to the construction of major dams, including Baixo-Sabor, Foz-Tua, and Alto-Tâmega (Braz et al., 2023).

In Andorra, efforts led by the government since 2002 have aimed at updating the species distribution map and assessing the impact of various threats (Lim et al., 2021b). In 2019, the Ministry of Environment was supposed to develop a restoration plan in favour of threatened species such as *Galemys pyrenaicus* (Consell General d'Andorra, 2019), but no update of such a document has been found to date.

## 4. Discussion

This systematic review reveals that *Galemys pyrenaicus* is not as unknown as previously assumed. For decades now, studies have provided several insights concerning its biology and ecology, fundamental to supporting future conservation initiatives. Such initiatives should be adapted according to local context to account for regional environment variations and potential genetic divergences.

### 4.1. Studies and monitoring

First, improving knowledge of *Galemys pyrenaicus* is crucial given the remaining grey areas concerning this mammal. Research should prioritize frequently updating distribution data, identifying core areas (Charbonnel et al., 2022) as well as favourable areas (Poduschka & Richard, 1986). Additionally, efforts in delimiting conservation management units (Tarrafeta Calvo et al., 2015, 2019), developing more efficient studying protocols and assessing the exact impact of major threats such as human-induced alterations of hydrology, climate change or invasive species should be implemented (Lim et al., 2022). The effects of parasites and infections could also be further studied to consider a health dimension when monitoring *Galemys pyrenaicus* (Ripa Lopez-Barrantes et al., 2023).

Further studies should account for regional environment and potential genetic differences: *Galemys pyrenaicus*'s habitat selection can differ among various watersheds of the same area (Biffi et al., 2016) and models are usually poorly transferable (Barbosa et al., 2011; Williams et al., 2012). Therefore, there is a need for thorough, regular and internationally standardized monitoring of its populations, using efficient, newly established protocols (Lim et al., 2021b) and non-invasive faeces-based techniques (Braz et al., 2023). For example, the current French national conservation plan for *Galemys pyrenaicus* favours 700 million transects of which only the first and the last 200 m are prospected to cover the home range of several individuals (cf. Supplementary material n°4 – “Behaviour and activity”) (Charbonnel et al., 2017; Lim et al., 2021b). Previous insights on the variations in detection probability should also be used to put more sampling efforts into the surveys
located in streams with high flow variability or with a homogeneous
substrate (Charbonnel et al., 2015). In France, the DREAL Occitanie
recommends prospecting *Galemys pyrenaicus*'s faeces between July and
October (or from mid-January to mid-March if needed) after 5 days with
no precipitation higher than 4 mm/day (Charbonnel et al., 2017). The
use of spatial replicates instead of temporal ones could also be imple-
mented on the least favourable stretches to reduce costs, provided that
the study's objectives allow it (Charbonnel et al., 2014). When data is
unavailable, downscaled coarse-resolution models might be a relevant
alternative (Barbosa et al., 2010).

Population analyses through the identification of each individual are also needed to assess their degree of isolation, their sex-ratio, their density and eventually viability, highlighting the importance of DNA-based techniques (Melero et al., 2014). As they vary in their efficiencies, costs, and biases, the DNA identification protocols should be wisely selected to make results as significant as possible (Esnaola et al., 2018a). The lack of genetic variability also requires the use of specific programs to differentiate highly inbred individuals (Escoda et al., 2022). Due to *Galemys pyrenaicus*'s seasonal movements, population increases or decreases cannot be inferred from punctual temporal replicates, and this semi-nomadic lifestyle should be taken into account in future models (Aymerich & Gosálbez i Noguera, 2015).

Providing the establishment of a standardized protocol, artificial
latrines could be a reliable method to detect the species, independent of
extreme weather events and causing less trampling pressure (Levy-
Otheguy et al., 2024; Lim et al., 2021b). However, compared to tradi-
tional faeces collection methodologies, this method is difficult to deploy
at a large spatial scale and requires frequent checks to avoid potential
faeces degradation and damages caused by flow variation or human
actions (González-Esteban et al., 2018; Lacaze & Servière, 2019). Live
trapping operations, despite their discussed efficiency, remain a useful
tool as they allow to monitor movements and behaviour of individuals
by radiotracking (Poncet et al., 2021). They should be led over entire
nights, favour 500 m- to 1 km-long trapping linear and use winglet traps
(Poncet et al., 2021). However, it must only be employed when neces-
sary, specifically to install radiotracking devices or to detect the species
in areas where faeces surveys cannot be carried out due to strong flow
variations or the absence of deposition substrates (Lim et al., 2020a). To
avoid disturbance during sensitive reproduction periods and to protect
newborns, they should also be avoided between February and August
(cf. Supplementary material n°4 – "Reproduction") (Lim et al., 2020a).
Improvements in environmental DNA analysis techniques should be
closely followed as these could be extremely useful for inaccessible
streams (Biffi, 2017; Poncet et al., 2021; Quaglietta et al., 2018; Stein-
metz et al., 2018). Similarly, training dogs to detect the species could be
a methodology worth exploring (Lim et al., 2020a).

## 4.2. Communicating and planning

Given the efforts needed to detect this elusive mammal, cooperation
between research institutes and private ecological monitoring consul-
tancies is crucial to maximize the range covered by ecological moni-
toring. Raising public awareness through clean walks along rivers or
educational activities is a way to avoid any misunderstanding with
fishermen for example but also to draw decision-makers' attention
(Agirre-Mendi, 2004; López-de-Sancha et al., 2022). *Galemys pyrenaicus*
has thereby become a flagship species (Melero et al., 2014), which could
in the long run increase the funding allocated to its conservation.

The conclusions from previous research should be used as a basis to
lobby impactful stakeholders such as public institutions. *Galemys pyra-
enaicus* could be considered in the mandatory environmental impact as-
sessments for infrastructures affecting its habitat (Conservación de la
Naturaleza y Espacios Naturales de Extremadura, 2018). Following the
guidelines released by the DREAL Occitanie in 2018 (Lim et al., 2020b), it
is mandatory in France to assess the presence or absence of the species
before any riverine projects within its distribution range. If presence is

established, the project's design must integrate measures to avoid the
impact (e.g. relocating work areas or scheduling activities outside sensi-
tive periods like breeding), then mitigate it (e.g. using sediment traps
during works or installing artificial bypassing rivers), and finally
compensate it if residual impacts remain (e.g. restoring its habitat
somewhere else).

A legal and constraining framework for river flow management con-
cerning irrigation practices and hydroelectricity uptakes should also be
implemented, restricting any alteration resulting in the morphological
homogenization of streams (Biffi et al., 2016). Legally required minimal
water flows downstream of a water uptake could ideally be determined on
a case-by-case basis using models adapted to the local context but should
never be lower than summer low-water flows (Lim et al., 2020b; Némoz &
Baran, 2019). Large dam removals in the Basque Spanish region have
turned out beneficial for *Galemys pyrenaicus* populations (Esnaola et al.,
2021; Urquijo Luengo, 2018; Yarzabal Etxebeste et al., 2018), and such a
policy could be expanded. Enlarging the network of protected areas, (e.g.
Natura 2000, national parks and nature reserves) based on local insights
should also be discussed as less than 5.5 % of the most suitable sections for
*Galemys pyrenaicus* in the French Pyrenees benefit from moderate to
strong protection (Charbonnel et al., 2022). Finally, buffer areas could be
implemented around the banks of crucial streams to favour riparian
vegetation (Conservación de la Naturaleza y Espacios Naturales de
Extremadura, 2018).

Dialogues should be engaged with industrial firms managing dams or
associated with potentially polluting activities. Agriculture areas near
streams occupied by *Galemys pyrenaicus* could be urged to reduce their
use of phytosanitary products and fertilizers (Conservación de la Natu-
raleza y Espacios Naturales de Extremadura, 2018). Despite documented
evidence of negative impacts in France, Portugal's commitments to
renewable energy make it unlikely that the threat of hydroelectricity
will decrease in the years to come (Pedroso & Chora, 2014). Therefore,
the question of how to curb their impact arises. To date, no study has
fully answered this question due to the heterogeneity in terms of size and
functioning of artificial barriers and fittings which impact rivers' natural
flow regimes (Charbonnel, 2015). Nevertheless, smaller hydraulic and
hydroelectric projects could be compatible with the conservation of
*Galemys pyrenaicus* if the projects are optimized to minimize impacts
(Charbonnel, 2015; Pedroso & Chora, 2014). Companies should thus be
guided in their actions.

## 4.3. Favouring *Galemys pyrenaicus*'s habitat

A more “operational” approach involves protecting and expanding
the habitat most suitable for *Galemys pyrenaicus*. Such an approach is
even more relevant given its “umbrella species” status (Lim et al.,
2021b). Priority should be given to the smallest and most endangered
subpopulations since it is unlikely that such river stretches will be
recolonized in case of extinction (Casadesús et al., 2001; Tarrafeta Calvo
et al., 2015). In relation to its imperfect detection and to foster better
connectivity between its populations, it is also important to protect
broadly its habitat, and not only the stretches it is known to occupy
(Gillet et al., 2016a; Lim et al., 2021a). Such considerations could extend
to terrestrial corridors (e.g. forests, shrublands, or pastures) between
headwaters of close streams from separated watersheds (Querejeta et al.,
2017).

Moreover, river obstacles such as abandoned weirs could be removed
to restore riffle areas and natural hydrological conditions. Cleaning
works leading to flow homogenization should be limited and flow
diverters could be implemented to artificially create some new riffle
areas, while actions should be led to reconnect tributaries given their
importance as refuge areas (Biffi, 2017; Charbonnel, 2015; Lim et al.,
2020b; Quaglietta et al., 2018). Impactful river works such as dam
maintenance could also be forbidden during periods of reproduction and
breeding from February to August (cf. Supplementary material n°4 –
“Reproduction”) (Lim et al., 2020b). As they have been observed to be
used by some individuals (Pedroso & Chora, 2014), fish ladders adapted to the morphology and ecology of *Galemys pyrenaicus* could be installed on the biggest water obstacles to restore connectivity (Escoda & Castresana, 2021), as well as adapted rock ramps or artificial bypassing rivers (Escoda et al., 2018; Lim et al., 2020b).

Water quality should also be enhanced in crucial areas in relation to its influence on *Galemys pyrenaicus*'s prey (Simal Ajo & Serdio Cosío, 2009). Water treatment plants should treat all waters before releasing industrially polluted waters into rivers and vegetation barriers around farms could help curb agriculture-related run-off pollution (Conservación de la Naturaleza y Espacios Naturales de Extremadura, 2018; Nores & Salvador Milla, 2017). Sediment removal by dredging or filtration techniques could be considered before draining dam reservoirs (Lim et al., 2020b). Aquatic leisure activities such as canyoning should also be forbidden in the most sensitive areas (Biffi, 2017).

Although the riverbed matters more, the riverbanks should not be forgotten, especially as they are key areas for the social organisation of the species (Carneiro et al., 2016; Lim et al., 2022; Melero et al., 2012). River construction works should be adapted by installing smooth protective fences, using lightweight equipment and preferring adapted temporary bridges supported outside riverbanks to fords (Lim et al., 2020b). Riprap, i.e. rocks artificially placed on the banks of a river to protect it from erosion, could be installed to provide more sheltering opportunities (Gillet et al., 2016a). Additionally, protecting and restoring riparian vegetation as well as implementing plant-based engineering techniques could be considered to stabilize riverbanks and limit pollution (Lim et al., 2020b). In light of the autopsies conducted in the French Pyrenees (Fournier-Chambrillon et al., 2019), potential lethal traps such as abandoned nets and bottles could be removed where possible, escape ladders could be installed in derivation canals, and water uptakes should be protected by adapted grids and strainers (the DREAL Occitanie in France, for example, recommends a mesh size of less than 15 mm) (Lim et al., 2020b). Although such operations obviously cannot be implemented on all rivers, organizing targeted cleanup campaigns with local communities could help raise awareness about the threats to *Galemys pyrenaicus* and other species while punctually contributing to restoring its habitat. Owners of hydraulic structures could specifically be targeted by such campaigns given their influence.

## 4.4. Managing *Galemys pyrenaicus* itself and associated species

Another operational approach consists of actively managing species themselves instead of their abiotic environment, which includes for example translocating *Galemys pyrenaicus* to favourable areas. Assisted migration has already been mentioned as a viable conservation strategy for *Galemys pyrenaicus* given its limited dispersal abilities (Morueta-Holme et al., 2010) and successfully implemented in the filling area of a newly built dam in the Tâmega watershed in Portugal (Braz et al., 2023). However, such interventions should be approached cautiously as they are often short-term solutions and may fail without prior studies on the local conditions and further habitat management. Particular attention should nevertheless be given to avoiding any mix between individuals from different genetic lineages (Castresana et al., 2013; Igea et al., 2013; Querejeta et al., 2016). Translocations could also be used to artificially restore gene flows between two close populations whose connectivity was recently altered, thereby limiting inbreeding processes and losses of fitness (Escoda & Castresana, 2021).

Likewise, there is a need to limit the spread of the American mink (Braz et al., 2023), by favouring the habitat of the fox, one of its natural predators, or by trapping and killing individuals. The same approach could be used to limit the spread of other species, such as exotic crayfish (Quaglietta et al., 2018). While it may be difficult to implement these measures across the entire distribution range of *Galemys pyrenaicus*, punctually targeting headwater streams could be relevant as such areas have been shown crucial to the species' survival in Northern Portugal (Quaglietta et al., 2018). Owners of domestic animals such as cats or

dogs should also be raised aware of the potential damage caused by their pets on wild fauna when left straying (Agirre-Mendi, 2004).

## 5. Conclusion

The lack of information regarding *Galemys pyrenaicus* has been significantly and quickly addressed over the past two decades. While studies in captivity from the previous century have mostly focused on its anatomy and other aspects of its biology, more recent publications have revealed various insights on its genetics and ecology thanks to the development of non-invasive DNA-based monitoring methods combined with statistical analysis but also radiotracking of individuals. Key findings include the genetic structure of the species, relationships with its biotic environment, habitat preferences, and seasonal movements. Several anthropogenic threats and some of their underlying mechanisms have also been identified, encompassing modification of hydrology by artificial obstacles, climate change, pollution, human use of rivers for leisure and other activities, and invasive species. However, local-scale studies across the whole range of *Galemys pyrenaicus* show that the impact of such threats varies depending on the area, highlighting the need for conservation actions tailored to local contexts and informed by long-term regional ecological monitoring. Initiatives should now focus on operational actions, such as the protection and the restoration of its habitat, both targeting riverbed and floodplain. Similarly, solutions could be found to limit the expansion of invasive species reported to have negative direct or indirect effects on *Galemys pyrenaicus* and its prey. Finally, assisted migration remains a short-term solution with a significant risk of failure, and should be considered only as a last-resort solution.

### Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

### Acknowledgements

We would like to thank Professor José Manuel Martinho Lourenço and Doctor André Ribeiro da Fonseca for their assistance.

This work is supported by National Funds by FCT – Portuguese Foundation for Science and Technology, under the projects UID/04033 (Centro de Investigação e de Tecnologias Agro-Ambientais e Biológicas – CITAB) and LA/P/0126/2020 (https://doi.org/10.54499/LA/P/0126/2020), and by an Erasmus+ Grant from the European Union under the “Student Mobility for traineeship” project n°2023-FR01-KA131-HED-000119542.

### Supplementary materials 1 to 4

Supplementary data to this article can be found online at https://doi.org/10.1016/j.jnc.2025.126923.

### Data availability

No data was used for the research described in the article.

### References

* Agirre-Mendi, P. (2004). Distribución y estado de conservación del desmán ibérico, *Galemys pyrenaicus* (E. Geoffroy Saint-Hilaire, 1811) (Mammalia: Erinaceomorpha) en la Comunidad Autónoma de La Rioja. *Zubia*, 22, 55-86.

* Almond, R. E. A., Grooten, M., Juffe Bignoli, D., & Petersen, T. (2022). Living Planet Report 2022—Building a nature-positive society. *WWF*.

* Alvarez, F., Gijón-Botella, H., Quinteiro, P., Rey, J., López-Román, F., & Sanmartín, M. (1994). Paracuaria hispanica n. sp. (Nematod: Acuariidae), a stomach parasite of the Pyrenean desman *Galemys pyrenaicus* Geoffr. (Insectivora: Talpidae), with a
redefinition of the genus Paracuaria Rao, 1951. *Systematic Parasitology*, **29**, 105–112.
https://doi.org/10.1007/BF00009806

Aymerich, P., & Gosálbez i Noguera, J. (2015). Evidencias de regresión local del desmán ibérico (*Galemys pyrenaicus*) en los Pirineos meridionales. *Galemys: Boletín informativo de la Sociedad Española para la conservación y estudio de los mamíferos*, **27** (1), 31–40. https://doi.org/10.7325/galemys.2015.a4

Barbosa, A. M., Real, R., & Vargas, J. (2010). Use of Coarse-Resolution Models of Species' Distributions to Guide Local Conservation Inferences. *Conservation Biology: The Journal of the Society for Conservation Biology*, **24**, 1378–1387. https://doi.org/10.1111/j.1523-1739.2010.01517.x

Barbosa, A. M., Real, R., & Vargas, J. (2011). Transferability of environmental favourability models in geographic space: The case of the Iberian desman (*Galemys pyrenaicus*) in Portugal and Spain. *Ecological Modelling*, **220**, 1067. https://doi.org/10.1016/j.ecolmodel.2010.12.004

Bauchot, R., Buisseret, C., Leroy, Y., & Richard, P. B. (1973). L'équipement sensoriel de la trompe du desman des Pyrénées (*Galemys pyrenaicus*, insectivora, talpidae). *Mammalia*, **37**, 17–24. https://doi.org/10.1515/mamm.1973.37.1.17

Bertrand, A., & Didier, B. (2008). Le desman des Pyrénées. Insectes, 148.

Biffi, M. (2017). *Influence of environmental factors and biotic interactions on the habitat selection and diet of the Pyrenean desman, Galemys pyrenaicus*. Université Toulouse 3 Paul Sabatier.

Biffi, M., Charbonnel, A., Buisson, L., Blanc, F., Némoz, M., & Laffaille, P. (2016). Spatial differences across the French Pyrenees in the use of local habitat by the endangered semi-aquatic Pyrenean desman (*Galemys pyrenaicus*). *Aquatic Conservation: Marine and Freshwater Ecosystems*, **26**, Article n/a-n/a. https://doi.org/10.1002/aqc.2612

Biffi, M., Gillet, F., Laffaille, P., Colas, F., Aulagnier, S., Blanc, F., Galan, M., Tiouchine-M., L.-Némoz, M., Buisson, L., & Michaux, J. (2017b). Novel insights into the diet of the Pyrenean desman (*Galemys pyrenaicus*) using next-generation sequencing molecular analyses. *Journal of Mammalogy*, **98**, https://doi.org/10.1093/jmammal/gyx070

Biffi, M., Laffaille, P., & Buisson, L. (2020). Local habitat preferences of a semi-aquatic mammal, the Pyrenean desman (*Galemys pyrenaicus*). *Mammalia*, **84**, 50–62. https://doi.org/10.1515/mammalia-2018-0035

Biffi, M., Laffaille, P., Jabiol, J., Andre, A., Gillet, F., Lamothe, S., Michaux, J., & Buisson, L. (2017a). Comparison of diet and prey selectivity of the Pyrenean desman and the Eurasian water shrew using next-generation sequencing methods. *Mammalian Biology - Zeitschrift Fur Saugetierkunde*, **87**. https://doi.org/10.1016/j.jmambio.2017.09.001

Braz, L., Pedroso, N., Fernández-González, A., & Quaglotta, L. (2023). *Galemys pyrenaicus* (Geoffroy, 1811)—Toupeira-de-água. *In Livro Vermelho dos Mamíferos de Portugal Continental*, **84–85**.

Bullock, A., & Acreman, M. (2003). The role of wetlands in the hydrological cycle. *Hydrology and Earth System Sciences*, **7**(3), 358–389. https://doi.org/10.5194/hess-7-358-2003

Callejo, A., & Delibes, M. (2008). Dieta de la nutria *Lutra lutra* (Linnaeus, 1758) en la cuenca del Ebro, norte de España. *Miscel·lanària Zoològica*, **11**(11).

Carneiro, V., Quaglotta, L., & Mota, P. (2016). Territorial and Social Behaviour of the Pyrenean desman (*Galemys pyrenaicus*) assessed from scat deposition.

Casadesús, F., Gosálbez, J., & Aymerich, P. (2001). Distribución de 'Galemys pyrenaicus' (Insectivora, Talpidae) a Catalunya. Orsis, Organismes i Sistemes: Revista de Botànica, Zoologia i Ecologia, ISSN 0213-4039, N°. 16, 2001, 93-110, 16.

Castién, E., & Gosálbez, J. (1994). Diet of *Galemys pyrenaicus* (Geoffroy, 1811) in the North of the Iberian Peninsula. *Netherlands Journal of Zoology*, **45**, 422–430. https://doi.org/10.1163/156854295X0039

Castién, E., & Gosálbez, J. (1999). Habitat and food preferences in a guild of insectivorous mammals in the Western Pyrenees. *Acta Theriologica*, **44**, 1–13. https://doi.org/10.4098/AT.arch.99-1

Castresana, J., Igea, J., Aymerich, P., Fernández-González, Á., & Gosálbez, J. (2013). *Filogeografía del Desmán ibérico (Galemys pyrenaicus)*. In y su distribución en la Red de Parques Nacionales (pp. 143–154).

Charbonnel, A. (2015). Influence multi-échelle des facteurs environnementaux dans la répartition du Desman des Pyrénées (*Galemys pyrenaicus*) en France. Institut National Polytechnique de Toulouse.

Charbonnel, A., Blanc, F., Laffaille, P., Némoz, M., & Buisson, L. (2022). Combining spatial dependence occupancy models and conservation gap analyses to promote species conservation: A case study with a threatened semi-aquatic mammal. *Biological Conservation*, **270**, Article 109567. https://doi.org/10.1016/j.biocon.2022.109567

Charbonnel, A., Blanc, F., Némoz, M., Buisson, L., Laffaille, P., Bodo, A., Fournier, C., Fournier, P., Fropier, N., Lacaze, V., Le Roux, B., Poncet, E., Pontcharraud, L., & Tribolet, L. (2017). Outils techniques pour la prise en compte du Desman des Pyrénées dans les procédures d'évaluations environnementales. Livret 2 – Outil cartographique d'alerte et cahier des charges pour la réalisation d'inventaires du Desman des Pyrénées. CEN MP, 28.

Charbonnel, A., Buisson, L., Biffi, M., D'Amico, F., Besnard, A., Aulagnier, S., Blanc, F., Gillet, F., Lacaze, V., Michaux, J. R., Némoz, M., Pagé, C., Sanchez-Perez, J. M., Sauvage, S., & Laffaille, P. (2015). Integrating hydrological features and genetically validated occurrence data in occupancy modelling of an endemic and endangered semi-aquatic mammal, *Galemys pyrenaicus*, in a Pyrenean catchment. *Biological Conservation*, **184**, 182–192. https://doi.org/10.1016/j.biocon.2015.01.019

Charbonnel, A., D'Amico, F., Besnard, A., Blanc, F., Buisson, L., Némoz, M., & Laffaille, P. (2014). Spatial replicates as an alternative to temporal replicates for occupancy modelling when surveys are based on linear features of the landscape. *Journal of Applied Ecology*, **51**(5), 1425–1433. https://doi.org/10.1111/1365-2664.12301

Charbonnel, A., Laffaille, P., Biffi, M., Blanc, F., Maire, A., Némoz, M., Sanchez-Perez, J. M., Sauvage, S., & Buisson, L. (2016). Can Recent Global Changes Explain

the Dramatic Range Contraction of an Endangered Semi-Aquatic Mammal Species in the journal Poneys? *PLOS ONE*, **11**(7), Article e0159941. https://doi.org/10.1371/journal.pone.0159941

Chora, S. (2001). *Galemys pyrenaicus*, Geoffroy 1811: Ecología espacio-temporal e capacidad de transposición da mini-hidrífica de Frágiles (Rio Paiva). Facultad de Cièncias da Universidade de Lisboa.

Consell General d'Andorra. (2019). Llei 7/2019, del 7 de febrer, de conservació del medi natural, de la biodiversitat i del païsatge. *Bullèt Oficial del Principat d'Andorra*, **22**, 1–21.

Conservación de la Naturaleza y Espacios Naturales de Extremadura. (2018). Plan de Recuperación del Desmán Ibérico (*Galemys pyrenaicus*) en Extremadura.

Covich, A. P., Palmer, M. A., & Crowl, T. A. (1999). The Role of Benthic Invertebrate Species in Freshwater Ecosystems: Zoobenthic species influence energy flows and nutrient cycling. *BioScience*, **49**(2), 119–127. https://doi.org/10.2307/1313537

Declerck, S. A. J., & de Senerpont Domis, L. N. (2023). Contribution of freshwater metazooplankton to aquatic ecosystem services: An overview. *Hydrobiologia*, **850** (12), 2795–2810. https://doi.org/10.1007/s10750-022-05001-9

Escoda, L., & Castresana, J. (2021). The genome of the Pyrenean desman and the effects of bottlenecks and inbreeding on the genomic landscape of an endangered species. *Evolutionary Applications*, **14**, https://doi.org/10.1111/eva.13249

Escoda, L., Fernández-González, Á., & Castresana, J. (2018). Quantitative analysis of connectivity in populations of a semi-aquatic mammal using kinship categories and network assortativity. *Molecular Ecology Resources*, **19**, https://doi.org/10.1111/1755-0998.12967

Escoda, L., González-Esteban, J., Gómez, A., & Castresana, J. (2017). Using relatedness networks to infer contemporary dispersal: Application to the endangered mammal *Galemys pyrenaicus*. *Molecular Ecology*, **26**, https://doi.org/10.1111/mec.14133

Escoda, L., Hawlitschek, O., González-Esteban, J., & Castresana, J. (2022). Methodological challenges in the genomic analysis of an endangered mammal population with low genetic diversity. *Scientific Reports*, **12**, 21390. https://doi.org/10.1038/s41598-022-25619-y

Ensaola, A., Arrizabalaga, A., González-Esteban, J., Elosegi, A., & Aihartza, J. (2018a). Determining diet from faeces: Selection of metabarcoding primers for the insectivore Pyrenean desman (*Galemys pyrenaicus*). *PLoS ONE*, **13**, https://doi.org/10.1371/journal.pone.0208986

Ensaola, A., González-Esteban, J., Elosegi, A., & Aihartza, J. (2017). Piriniotako muturluizearen (*Galemys pyrenaicus*) ekologia espazial eta trofikoa: Kontserbaziorako funtzeko faktoreak. doi: 10.26876/ikergazte.ii.05.10.

Ensaola, A., González-Esteban, J., Elosegi, A., Arrizabalaga, A., & Aihartza, J. (2018b). Need for speed: Preference for fast-flowing water by the endangered semi-aquatic Pyrenean desman (*Galemys pyrenaicus*) in two contrasting streams. *Aquatic Conservation Marine and Freshwater Ecosystems*, **28**, https://doi.org/10.1002/aqc.2893

Ensaola, A., Larraina, A., González-Esteban, J., Elosegi, A., & Aihartza, J. (2023). Using biological traits to assess diet selection: The case of the Pyrenean desman. *Journal of Mammalogy*, **104**, https://doi.org/10.1093/jmammal/gyad061

Ensaola, A., Mata, V., Arrizabalaga, A., González-Esteban, J., Larraina, A., Rebelo, H., Elosegi, A., & Aihartza, J. (2021). It is the ambience, not the menu. In *Prey availability does not drive habitat selection by the endangered Pyrenean desman. Aquatic Conservation Marine and Freshwater Ecosystems* (p. 31). https://doi.org/10.1002/aqc.3563

Fernández-García, J. (2024). First evidence of predation on the native endangered *Galemys pyrenaicus* by the invader specie American mink using eDNA tools in Extremadura (Spain). https://doi.org/10.21203/rs.3.rs-3923939/v1.

Fernández-García, J., & Vivas-Cedillo, M. (2017). Faecal DNA template as non-invasive tools in order to distinguish the endangered Pyrenean desman (*Galemys pyrenaicus*, elupitophtha, talpidae) from mediterranean water shrews (*Neomys anomalus*, soricomorpha, soricidae). *Hystrix*, **28**, https://doi.org/10.4404/hystrix-28.1-12307

Fernández-González, Á., García Perez, J., Menendez, D., & Fernández, D. (2014a). Evidencias de una ocupación temporal por parte del desmán ibérico (*Galemys pyrenaicus*) de cursos fluviales, con una marcada estacionalidad, en el norte de Portugal. *Galemys, Spanish Journal of Mammalogy*, **26**, https://doi.org/10.7325/Galemys.2014.A6

Fernández-González, Á., García Perez, J., Menendez, D., Fernández López, J., Fernández, D., & Santamarina, J. (2014b). Nuevos datos sobre la distribución del desmán ibérico (*Galemys pyrenaicus*) en Galicia. *Proyecto LIFE + MARGALULLA. Galemys Spanish Journal of Mammalogy*, **26**, https://doi.org/10.7325/Galemys.2014.N4

Fernández López, J., Fernández-González, Á., & Fernández, D. (2014). Confirmación de la depredación de nutria paleártica *Lutra lutra* (Linnaeus, 1758) sobre desmán ibérico *Galemys pyrenaicus* (E. Geoffroy Saint-Hilaire, 1811) mediante el empleo de técnicas moleculares. *Galemys, Spanish Journal of Mammalogy*, **26**, 96–99. https://doi.org/10.7325/Galemys.2014.N2

Fournier-Chambrillon, C., Vial-Novella, C., Blanc, F., Durand, M.-O., Lacaze, V., Lafitte J., Levenard, P., Le Roux, B., Miquel, J., Némoz, M., Sourp, E., Torres, J., & Fournier, P. (2019). Bilan de 10 ans d'autopsies de Desmans : causes de mortalités et autres enseignements. Colloque de restitution du LIFE+ Desman, décembre 2019, ENSAT, Auzeville-Tolosane (31-France).

García, P., & Mateos, I. (2007). Comportamiento cavernícola del desmán ibérico *Galemys pyrenaicus* (E. Geoffroy Saint-Hilaire, 1811) en la montaña palentina. *Galemys*, **27**, 41–45.

Gillet, F., Cabria, M., Némoz, M., Blanc, F., Fournier-Chambrillon, C., Sourp, E., Vial-Novella, C., Aulagnier, S., & Michaux, J. (2014). PCR-RFLP identification of the endangered Pyrenean desman, *Galemys pyrenaicus* (Soricomorpha, Talpidae), based on faecal DNA. *Mammalia*, **79**, https://doi.org/10.1515/mammalia-2014-0093
Gillet, F., Garrido, M., Blanc, F., Fournier-Chambrillon, C., Nemoz, M., Sourp, E., Vial-Novella, C., Zardoya, R., Aulagnier, S., & Michaux, J. (2016a). Evidence of fine-scale genetic structure for the endangered Pyrenean desman (*Galemys pyrenaicus*) in the French Pyrenees. *Journal of Mammalogy*, **98**. https://doi.org/10.1093/jmammal/gyx002

Gillet, F., Roux, B., Blanc, F., Bodo, A., Fournier-Chambrillon, C., Fournier, P., Jakob, F., Lacaze, V., Némoz, M., Aulagnier, S., & Michaux, J. (2016b). Genetic monitoring of the endangered Pyrenean desman (*Galemys pyrenaicus*) in the Aude River, France. *Belgian Journal of Zoology*, **146**, 44–52. https://doi.org/10.26496/bjz.2016.38

Gillet, F., Tiouchichine, M.-L., Galan, M., Blanc, F., Némoz, M., Aulagnier, S., & Michaux, J. (2015). A new method to identify the endangered Pyrenean desman (*Galemys pyrenaicus*) and to study its diet, using next generation sequencing from faeces. *Mammalian Biology*, **80**, 505–509. https://doi.org/10.1016/j.mambio.2015.08.002

Gisbert, J., & García-Perea, R. (2014). Historia de la regresión del desmán ibérico *Galemys pyrenaicus* (E. Geoffroy Saint-Hilaire, 1811) en el Sistema Central (Península Ibérica). *Munibe Monographs. Nature Series*, **3**, 19–35. https://doi.org/10.21630/mmns.2014.3.03

González-Esteban, J., Esnaola, A., & Aihartza, J. (2018). A new sampling method to detect the Pyrenean desman (*Galemys pyrenaicus*). *Hystrix*. https://doi.org/10.4404/hystrix-00078-2018

González-Esteban, J., Villate, I., & Castién, E. (2003). A comparison of methodologies used in the detection of the Pyrenean desman *Galemys pyrenaicus* (E. Geoffroy, 1811). *Mammalian Biology*, **68**(6), 387–390. https://doi.org/10.1078/1616-5047-00107

González-Esteban, J., Villate, I., Castién, E., Rey, I., & Gosálbez, J. (2002). Age determination of *Galemys pyrenaicus*. *Acta Theriologica*, **47**, 107–112. https://doi.org/10.1007/BF03193570

Hawlitschek, O., Fernández-González, Á., Puente, A., & Castresana, J. (2018). A pipeline for metabarcoding and diet analysis from fecal samples developed for a small semi-aquatic mammal. *PLOS ONE*, **13**, Article e0201763. https://doi.org/10.1371/journal.pone.0201763

Hernández, A. (1988). Observaciones sobre la distribución, hábitat y comportamiento del Topo de Rio *Galemys pyrenaicus* en el Río Torío (León). *Miscelánia Zoologica*, **12**.

Igea, J., Aymerich, P., Fernández-González, Á., González-Esteban, J., Gómez, A., Alonso, R., Gosálbez, J., & Castresana, J. (2013). Phylogeography and postglacial expansion of the endangered semi-aquatic mammal *Galemys pyrenaicus*. *BMC Evolutionary Biology*, **13**, 115. https://doi.org/10.1186/1471-2148-13-115

IPCC. (2023). Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. IPCC, Geneva, Switzerland. https://doi.org/10.59327/IPCC/AR6-9789291691647

Kauhala, K. (1996). Introduced carnivores in Europe with special reference to central and northern Europe. *Wildlife Biology*, **2**, 197–204. https://doi.org/10.2981/wlb.1996.019

Lacaze V., Servière L. (2019). Des tunnels pour la détection du Desman des Pyrénées (Conference presentation). Jères rencontres naturalistes d'Occitanie, Gruais, France.

Leyv-Otheguy, J., Aihartza, J., González-Esteban, J., & Elosegi, A. (2024). The efficiency of artificial latrines to detect and describe distribution patterns of the Pyrenean desman (*Galemys pyrenaicus*). *Hystrix*. https://doi.org/10.4404/hystrix-00640-2023

Lim, M., Blanc, F., Michaux, J., Pigneur, L.-M., Gillet, F., Marc, D., Poncet, E., & Némoz, M. (2021a). Etude comparative de la densité et du déplacement des Desmans des Pyrénées *Galemys pyrenaicus* (E. Geoffroy Saint-Hilaire, 1811) par une méthode non invasive. *Naturae*. https://doi.org/10.5852/naturae2021a17

Lim, M., Fournier-Chambrillon, C., Poncet, E., Lacaze, V., Fournier, P., Blanc, F., & Némoz, M. (2022). Suivi par radiopistage du Desman des Pyrénées *Galemys pyrenaicus* (E. Geoffroy Saint-Hilaire, 1811) sur deux cours d'eau d'Ariège : Rythme d'activité, utilisation de l'espace et influence des variations de débit. *Naturae*. https://doi.org/10.5852/naturae2022a12

Lim, M., Némoz, M., Blanc, F., Poncet, E., & Xéridat, P. (2021b). *Plan national d'actions 2021-2030 en faveur du Desman des Pyrénées Galemys pyrenaicus*. Toulouse: CEN Occitanie & DREAL Occitanie.

Lim, M., Némoz, M., Fournier-Chambrillon, C., Poncet, E., Blanc, F., & Xéridat, P. (2020a). Outils techniques pour la prise en compte du Desman des Pyrénées dans les procédures d'évaluations environnementales. *Livret 3 - Cahier des charges pour la réalisation des suivis du Desman des Pyrénées. CEN MP*.

Lim, M., Xéridat, P., Némoz, M., Poncet, E., Blanc, F., Fournier-Chambrillon, C., Fournier, P., Le Roux, B., Lacaze, V., Bodo, A., Mazery, B., & Mansanné, E. (2020b). Outils techniques pour la prise en compte du Desman des Pyrénées dans les procédures d'évaluations environnementales. *Livret 4 - Guide technique de recommandations pour la gestion du Desman des Pyrénées et de ses habitats. CEN MP*.

Lima, D. C. A., Lemos, G., Bento, V. A., Nogueira, M., & Soares, P. M. M. (2023). A multi-variable constrained ensemble of regional climate projections under multi-scenarios for Portugal - Part I: An overview of impacts on means and extremes. *Climate Services*, **30**, Article 100351. https://doi.org/10.1016/j.cliser.2023.100351

López-de-Sancha, A., Roig, R., Aymerich, P., Vila-Gispert, A., & Guasch, H. (2022). Trophic competition in a guild of insectivorous semi-aquatic vertebrates in a Pyrenean headwater stream: Diet specialisation in the endangered *Galemys pyrenaicus*. *Mammalian Biology - Zeitschrift Fur Saugetierkunde*, **102**. https://doi.org/10.1007/s42991-022-00265-z

Melero, Y., Aymerich, P., Luque-Larena, J., & Gosalbez, J. (2012). New insights into social and space use behaviour of the endangered Pyrenean desman (*Galemys pyrenaicus*). *European Journal of Wildlife Research*, **58**, 185–193. https://doi.org/10.1007/s10344-011-0561-7

Melero, Y., Aymerich, P., Santulli Sanzo, G., & Gosálbez, J. (2014). Activity and space patterns of Pyrenean desman (*Galemys pyrenaicus*) suggest non-aggressive and non-territorial behaviour. *European Journal of Wildlife Research*, **60**, 707–715. https://doi.org/10.1007/s10344-014-0838-8

Meyer, J., Strayer, D., Wallace, J., Eggert, S., Helfman, G., & Leonard, N. (2007). The Contribution of Headwater Streams to Biodiversity in River Networks1. *JAWRA Journal of the American Water Resources Association*, **43**(1), 86–103. https://doi.org/10.1111/j.1752-1688.2007.00008.x

Ministère de la Transition Ecologique et Solidaire. (2018). Données de synthèse Époques issues du rapportage au titre de la directive Habitats - période 2013-2018 (INPN ID n° A2ECEC7B-5978-36C9-E503-2614A8C0F123). *INPN OpenObs*. https://openobs.mnhn.fr/.

Morueta-Holme, N., Flejgaard, C., & Svenning, J.-C. (2010). Climate Change Risks and Conservation Implications for a Threatened Small-Range Mammal Species. *PloS One*, **5**, Article e10360. https://doi.org/10.1371/journal.pone.0010360

Némoz, E., & Baran, P. (2019). Débit minimum biologique pour le Desman des Pyrénées : première approche pour la caractérisation de préférences hydrauliques et de sensibilité des habitats de l'espace aux débits [Conference presentation]. Toulouse: Colloque de clôture du projet LIFE+ Desman.

Némoz, M., Bertrand, A., Sourrie, M., & Arlot, P. (2011). A French Conservation Action Plan for the Pyrenean desman *Galemys pyrenaicus*. *SECEM*. https://secem.es/galemys/galemys-23-2011-a6.

Nores, C., Ojeda, F., Ruano, A., González-Esteban, J., Cano, J., & García Álvarez, H. E. (1992). Aproximación a la metodología y estudio del área de distribución, estatus de población y selección de hábitat del desmán (*Galemys pyrenaicus*) en la Península Ibérica [Unpublished manuscript]. ICONA - Universidad de Oviedo.

Nores, C., Ojeda, F., Ruano, A., Villate, I., González-Esteban, J., Cano, J., & García, E. (1998). Estimating the population density of *Galemys pyrenaicus* in four Spanish rivers. *Journal of Zoology*, **246**, 454–457. https://doi.org/10.1111/j.1469-7998.1998.tb00179.x

Nores, C., & Salvador Milla, A. (2017). Desmán ibérico – *Galemys pyrenaicus* (E. Geoffroy, 1811). https://doi.org/10.20350/digitalCSIC/8866.

Page, M., Mckenzie, J., Bossuyt, P., Boutron, I., Hoffmann, T., Mulrow, C., Shamseer, L., Tetzlaff, J., Akl, E., Brennan, S., Chou, R., Glanville, J., Grimshaw, J., Hróbjartsson, A., Lalu, M., Li, T., Loder, E., Mayo-Wilson, E., McDonald, S., & Moher, D. (2021). The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. *BMJ, 372*, Article n71. https://doi.org/10.1136/bmj.n71

Palmeirim, J. M., & Hoffmann, R. S. (1983). *Galemys pyrenaicus*. *Mammalian Species*, **207**, 1–5. https://doi.org/10.2307/3503939

Pedroso, N., & Chora, S. (2014). The Iberian desman *Galemys pyrenaicus* (E. Geoffroy Saint-Hilaire, 1811) in Portugal: Status and conservation. *In Munibe Monographs. Nature Series*, **3**, 13–18. https://doi.org/10.21630/mmns.2014.3.02

Peyre, A. (1956). Ecologie et biogéographie du desman (*Galemys pyrenaicus* G.) Dans les pyrénées françaises. *Mammalia*, **20**, 405–418. https://doi.org/10.1515/mamm.1956.20.4.405

Poduschka, W., & Richard, P. B. (1986). The Pyrenean desman—An endangered insectivore. *Oryx*, **20**, 230–232. https://doi.org/10.1017/S0030605300020251

Poncet, E., Blanc, F., Lim, M., Némoz, M., & Marc, D. (2021). Desman des Pyrénées (*Galemys pyrenaicus*) E. Geoffroy Saint-Hilaire, 1811. 2018 des des des Pyrénées françaises. *Naturae*, **2021**, 35–47. https://doi.org/10.5852/naturae2021a3

Quaglietta, L. (2012). IUCN Red List of Threatened Species. *Galemys pyrenaicus*. IUCN Red List of Threatened Species.

Quaglietta, L., & Beja, P. (2018). Direct observations of vertebrate killing and consumption by the endangered Pyrenean desman (*Galemys pyrenaicus*). *Mammalia*. https://doi.org/10.1515/mammalia-2018-0111

Quaglietta, L., Paupério, J., Martins, F., Alves, P., & Beja, P. (2018). Recent range contractions in the globally threatened Pyrenean desman highlight the importance of stream headwater refugia. *Animal Conservation*, **21**. https://doi.org/10.1111/acv.12422

Queiroz, A. (1996). Sobre o comportamento das toupeiras-de-água, *Galemys pyrenaicus* Geoffroy e Desmana moschata L. (Desmaninae, Talpidae, Insectivora). *Instituto Superior de Psicologia Aplicada*.

Queiroz, A., Quaresma, C., Santos, C., Barbosa, A., & Carvalho, H. (1998). Bases para a Conservação da Toupeira-de-água (*Galemys pyrenaicus*). *Estudos de Biologia e Conservação da Natureza*, **27**–118.

Queirejeta, M., Fernández-González, Á., Romero Suances, R., & Castresana, J. (2017). Postglacial dispersal patterns and mitochondrial genetic structure of the Pyrenean desman (*Galemys pyrenaicus*) in the northwestern region of the Iberian Peninsula. *Ecology and Evolution*, **7**, 1–10. https://doi.org/10.1002/ece3.3034

Queirejeta, M., González-Esteban, J., Gómez, A., Fernández-González, Á., Aymerich, P., Gosálbez, J., Escoda, L., Igea, J., & Castresana, J. (2016). Genomic diversity and geographical structure of the Pyrenean desman. *Conservation Genetics*, **17**. https://doi.org/10.1007/s10592-016-0865-y

Reid, A., Carlson, A., Creed, I., Eliason, E., Gell, P., Johnson, P., Kidd, K., MacMackinn, T., Olden, J., Ormerod, S., Smol, J., Taylor, W., Tockner, K., Vermaire, J., Dudgeon, D., & Cooke, S. (2019). Emerging threats and persistent conservation challenges for freshwater biodiversity. *Biological Reviews*, **94**(3), 849–873. https://doi.org/10.1111/brv.12480

Richard, P. B. (1973). Le Desman des Pyrénées (*Galemys pyrenaicus*): Mode de vie, univers sensoriel. *Mammalia*, **37**, 1–16. https://doi.org/10.1515/mamm.1973.37.1.1

Richard, P. B., & Viallard, A. (1969). Le Desman des Pyrénées (*Galemys pyrenaicus*): Premières notes sur sa biologie. *La Terre et La Vie, Revue d'Histoire Naturelle*, **23**. https://doi.org/10.3406/revec.1969.4564

Ripa Lopez-Barrantes, A., Díaz-Caballero, J., Palacios-González, M., Espinosa, A., Zapata, J. L., & Fernández-García, J. L. (2024). Application of real-time PCR for the
identification of the endangered species *Galemys pyrenaicus* through faecal samples. *Molecular Biology Reports*, 51. https://doi.org/10.1007/s11033-023-09010-2

Ripa Lopez-Barrantes, A., Díaz-Caballero, J., Palacios-González, M., Zalba, J., Espinosa, A., Zapata, J. L., Gómez-Martín, A., Tkach, V., & Fernández-García, J. L. (2023). Non-Invasive Wildlife Disease Surveillance Using Real Time PCR Assays: The Case of the Endangered *Galemys pyrenaicus* Populations from the Central System Mountains (Extremadura, Spain). *Animals*, 13, 1136. https://doi.org/10.3390/ani13071136

Russo, L. F., Fernández-González, Á., Penteriani, V., Delgado, M. D. M., Palazón, S., Loy, A., & Di Febbraro, M. (2023). The Different Fate of the Pyrenean desman (*Galemys pyrenaicus*) and the Eurasian Otter (*Lutra lutra*) under Climate and Land Use Changes. *Animals: An Open Access Journal from MDPI*, 13(2), 274. https://doi.org/10.3390/ani13020274

Santamarina, J. (1993). Feeding ecology of a vertebrate assemblage inhabiting a stream of NW Spain (Riobo, Ulla basin). *Hydrobiologia*, 252, 175-191. https://doi.org/10.1007/BF00008154

Santamarina, J. (1995). Distribución de algunas especies de vertebrados terrestres en la cuenca del río Ulla (Galicia) en relación con la calidad de las aguas | Margal Ulla. 9, 353-365.

Santamarina, J., & Guitian, J. (1988). Quelques données sur le régime alimentaire du desman (*Galemys pyrenaicus*) dans le nord-ouest de l'Espagne. *Mammalia*, 52. https://doi.org/10.1515/mamm-1988-0301

Schleussner, C.-F., Menke, I., Theokritoff, E., Van Maanen, N., & Lanson, A. (2020). Climate impacts in Portugal. https://youth4climatejustice.org/wp-content/uploads/2021/01/Climate-Analytics-Climate-Impacts-in-Portugal-min.pdf.

Simal Ajo, R., & Serdio Cosio, A. (2009). El Desmán Ibérico (*Galemys pyrenaicus*) en Cantabria. *Locustella: Anuario de la Naturaleza de Cantabria*, 6, 80-88.

Steinmetz, J., Ruette, S., Ruys, T., Jean, P., & Dejean, T. (2018). Vers une nouvelle méthode de détection des espèces de mammifères semi-aquatiques : étude pilote et approche « Metabarcoding ADNe ». *Faune sauvage*, 319(2), 11-17.

Stone, R. (1987a). The activity patterns of the Pyrenean desman (*Galemys pyrenaicus*) (Insectivora: Talpidae), as determined under natural conditions. *Journal of Zoology*, 213, 95-106. https://doi.org/10.1111/j.1469-7998.1987.tb03680.x

Stone, R. (1987b). The social ecology of the Pyrenean desman (*Galemys pyrenaicus*) (Insectivora: Talpidae), as revealed by radiotelemetry. *Journal of Zoology*, 212, 117-129. https://doi.org/10.1111/j.1469-7998.1987.tb05119.x

Tarrafeta Calvo, L., Fernández-González, Á., & Pérez-Ceballos, E. (2015). Identificación de barreras y determinación de Unidades de Gestión territorial para el Desmán ibérico (*Galemys pyrenaicus*) en León (N Spain).

Tarrafeta Calvo, L., Fernández-González, Á., & Perez-Collazos, E. (2019). *Galemys pyrenaicus* en la vertiente meridional de la Cordillera Cantábrica: Identificación de unidades de manejo como herramienta para la conservación de poblaciones amenazadas. 21, 155-173.

Tomscha, S. A., Gergel, S. E., & Tomlinson, M. J. (2017). The spatial organization of ecosystem services in river-floodplains. *Ecosphere*, 8(3), Article e01728. https://doi.org/10.1002/ecs2.1728

Urquijo Luengo, A. (2018). Hacia la recuperación de la permeabilidad del río Leitzaran. Demolición de la presa de Inturia. Retos y experiencias de restauración fluvial en el ámbito de la Red Natura 2000, 2018, 194-203.

Vidal, O., Pérez-Serra, A., & Pla, C. (2010). A sex determination protocol for the Iberian desman (*Galemys pyrenaicus*) based on a three-primer amplification of DBX and DBY fragments with non-invasive samples. *Conservation Genetics*, 11, 1185-1187. https://doi.org/10.1007/s10592-009-9913-1

Williams, M., D'Amico, F., Page, C., Bertrand, A., Némoz, M., & Brown, J. (2012). Modeling Rare Species Distribution at the Edge: The Case for the Vulnerable Endemic Pyrenean desman in France. *The Scientific World Journal*, 2012, Article 612965. https://doi.org/10.1100/2012/612965

Yarzabal Etxebeste, A., Martín Vide, J. P., Elosegi Irurtia, A., & Díez López, J. R. (2018). El desmantelamiento de la presa de Enobieta: Último obstáculo a la conectividad fluvial en Artikutza. Retos y experiencias de restauración fluvial en el ámbito de la Red Natura, 2000 (2018), 180-193.