Invertebrates Research Articles

Structural Indices of the Communities of Benthic and Phytophilous Invertebrates in Water Bodies Differing in the Dose Rate of Ionizing Radiation

The structural indices of the communities of benthic and phytophilous invertebrates were studied in water bodies differing in the levels of external radiation dose rate within the Chornobyl exclusion zone. The macrofauna of invertebrates of all studied water bodies was characterized by low species richness, numbers, and biomass. The obtained results suggest that the benthic and phytophilous invertebrate fauna of the cooling pond of the Chornobyl Nuclear Power Plant differs in its structure from the fauna of other water bodies of the Chornobyl exclusion zone more significantly than these water bodies differ from each other in terms of dose load levels on the biota. We consider the main reason for these differences to be the succession processes in the ecosystem caused by the transformation of the cooling pond of the Chornobyl Nuclear Power Plant. There is no reason to claim that the influence of external ionizing radiation determines the change in the structural indices of the communities of benthic and phytophilous invertebrates in water bodies of the Chornobyl exclusion zone.

Bats (Chiroptera) of the Ujście Warty National Park and the surrounding area

Bat research was carried out in 2012-2013 in the Ujście Warty National Park and in adjacent areas. Bats were caught in chiropterological nets, searched for in winter and summer roosts. Detector listening was carried out and the owls' diet was analyzed for the presence of bats among their prey. In the national park area, 11 species of bats were detected, and together with the Natura 2000 area "Ujście Warty" and the neighbouring areas, a total of 15 species were detected: the Daubenton's bat Myotis daubentonii, Natterer's bat Myotis nattereri, Brandt's bat Myotis brandtii, noctule bat Nyctalus noctula, serotine bat Eptesicus serotinus, common pipistrelle bat Pipistrellus pipistrellus, soprano pipistrelle bat Pipistrellus pygmaeus, Nathusius' pipistrelle bat Pipistrellus nathusii, brown long-eared bat Plecotus auritus, gray long-eared bat Plecotus austriacus, western barbastelle bat Barbastella barbastellus, greater mouse-eared bat Myotis myotis, Bechstein's bat Myotis bechsteinii, pond bat Myotis dasycneme and the parti-coloured bat Vespertilio murinus. The bat fauna of this area is relatively rich compared to other protected areas and presented results constitute an important supplement to the knowledge about the vertebrate fauna of the national park and its vicinity.

Systematic camera trapping survey for terrestrial vertebrates in Xuan Lien Nature Reserve, Vietnam.

Xuan Lien Nature Reserve was established in 1999 to protect important habitats and wildlife in the northern part of the Annamites in Vietnam. While Xuan Lien is home to many threatened species, it has experienced a high level of human disturbance over the last decades. To document and provide baseline data on the status and distribution of the terrestrial vertebrate fauna community in the region, we conducted a systematic camera trapping survey in Xuan Lien Nature Reserve in 2023. The data collected during the survey will help design proper conservation measures to better conserve the remaining species. Our study investigates and updates the species richness of mid- to large-sized terrestrial vertebrates, thus providing essential information for developing conservation strategies in Xuan Lien Nature Reserve, Vietnam. As camera traps were set up in a grid-based design, our survey also generated the first-ever systematic data for terrestrial vertebrate fauna in the area. The study covers approximately 21,000 hectares (about 77% of the area), using 35 camera trap stations; each station consists of two cameras. In total, the final dataset consists of 6,276 trap nights, recording at least 46 species in 39 genera. The results suggest that Xuan Lien is a key stronghold for small carnivores, based on the diversity of such species groups in the Reserve. We failed to detect the previously documented Roosevelt's muntjac (Muntiacusrooseveltorum Osgood, 1932) and we only documented a single record of the northern red muntjac (Muntiacusvaginalis Boddaert, 1785). Our survey confirms the severity of overhunting and other anthropogenic threats to the mammal fauna, especially ungulates, in the Reserve.

A new moradisaurine captorhinid reptile (Amniota: Eureptilia) from the upper Permian of India.

Upper Permian rocks of the former supercontinent Gondwana record climax late Paleozoic terrestrial vertebrate faunas that were dominated numerically and ecologically by therapsid synapsids. Older faunal elements of earlier Paleozoic faunas, such as captorhinid reptiles, are rare and scattered components of the first amniote faunas to inhabit high-latitude regions. Here we describe a new genus and species of moradisaurine captorhinid that represents an archaic faunal element of the high-fibre herbivore fauna of the late Permian of what is now peninsular India. The presence of a relatively broad parietal and three rows of conical teeth on the maxilla and the dentary distinguishes Indosauriscus kuttyi gen. et sp. nov. from other moradisaurines. The hypodigm of I. kuttyi comprises skulls that range in length from 39 mm to 54mm, and high ossification of the braincase elements and well developed skull-roof sutures, indicate that I. kuttyi adults were smaller than those of most moradisaurines. Results of our phylogenetic analyses suggest that moradisaurines, despite appearing first in the paleotropics, dispersed into temperate, high-latitude regions of Pangea early in their evolutionary history. Moradisaurines in dicynodont-dominated faunas, viz. Indosauriscus kuttyi and Gansurhinus naobaogouensis, were the smallest high-fibre herbivores in their respective faunas. This suggests that small body size may have evolved in these moradisaurines as they co-evolved with the more numerous and diverse dicynodont therapsids.

The late-Quaternary megafauna extinctions: Patterns, causes, ecological consequences and implications for ecosystem management in the Anthropocene

Abstract Across the last ~50,000 years (the late Quaternary) terrestrial vertebrate faunas have experienced severe losses of large species (megafauna), with most extinctions occurring in the Late Pleistocene and Early to Middle Holocene. Debate on the causes has been ongoing for over 200 years, intensifying from the 1960s onward. Here, we outline criteria that any causal hypothesis needs to account for. Importantly, this extinction event is unique relative to other Cenozoic (the last 66 million years) extinctions in its strong size bias. For example, only 11 out of 57 species of megaherbivores (body mass ≥1,000 kg) survived to the present. In addition to mammalian megafauna, certain other groups also experienced substantial extinctions, mainly large non-mammalian vertebrates and smaller but megafauna-associated taxa. Further, extinction severity and dates varied among continents, but severely affected all biomes, from the Arctic to the tropics. We synthesise the evidence for and against climatic or modern human (Homo sapiens) causation, the only existing tenable hypotheses. Our review shows that there is little support for any major influence of climate, neither in global extinction patterns nor in fine-scale spatiotemporal and mechanistic evidence. Conversely, there is strong and increasing support for human pressures as the key driver of these extinctions, with emerging evidence for an initial onset linked to pre-sapiens hominins prior to the Late Pleistocene. Subsequently, we synthesize the evidence for ecosystem consequences of megafauna extinctions and discuss the implications for conservation and restoration. A broad range of evidence indicates that the megafauna extinctions have elicited profound changes to ecosystem structure and functioning. The late-Quaternary megafauna extinctions thereby represent an early, large-scale human-driven environmental transformation, constituting a progenitor of the Anthropocene, where humans are now a major player in planetary functioning. Finally, we conclude that megafauna restoration via trophic rewilding can be expected to have positive effects on biodiversity across varied Anthropocene settings.

Challenges in reconstructing the vegetation associated with a late Eocene mammal fauna from Western Europe

Bed TB33, a lacustrine unit within the late Eocene (early Priabonian) How Ledge Limestone, Headon Hill, Isle of Wight, UK, contains a rich mammalian fauna. The previously reconstructed food web included mammalian predators and prey (ground dwelling, scansorial and arboreal; insectivores, frugivores, herbivores and carnivores) and two inferred owls. Unfortunately, the extensive bulk sediment sampling and sieving used to obtain the vertebrate fauna had not yielded any plant fossils other than charophyte gyrogonites. This new work has focused on plant mesofossils and palynofacies in the uppermost horizons of the vertebrate-rich bed aiming to reconstruct the vegetation that hosted the mammals. Other than cysts of Zygnemataceae, phytoplankton are absent. The presence of the aquatic plants Azolla and Salvinia on the lake is documented by megaspores and microspore massulae. The palynomorphs are dominated by algal cysts, Azolla microspore massulae fragments and two morphologies of trilete fern spores. These data document a depositional setting in a lake with abundant free-floating Azolla or Salvinia and with a margin vegetation dominated by ferns. The data support one of our previous inferences that the arboreal mammals were brought to the site from some distance away by predators. However, the challenge to fully reconstruct the mammalian habitats remains.

Occurrence, abundance and seasonal distribution of benthic macro invertebrates in relation to the water quality and bottom soil properties in a fish pond

Occurrence, abundance and seasonal distribution of benthic macro invertebrates in relation to the water quality and bottom soil properties in a fish pond

Diversity of Macro Invertebrates of the River Rwizi in Western Uganda: A Citizen Science-BioBlitz Approach

Diversity of Macro Invertebrates of the River Rwizi in Western Uganda: A Citizen Science-BioBlitz Approach

Squirrels (Rodentia, Sciuridae) of the Early Miocene Tagay fauna in Eastern Siberia

The Tagay vertebrate fauna (Olkhon Island, Lake Baikal, Russia) dated to the late Early Miocene yielded a diverse association of sciurine rodents, including flying squirrel Hylopetes sp., tree squirrels Sciurus cf. lii, Sciurus sp., and Blackia cf. miocaenica, and a numerically dominant small marmotine Miospermophilus debruijni. The presence of flying and tree squirrels indicates the presence of wooded biotopes. The record of Blackia is remarkably distant (more than 4000 km) from the nearest synchronous records in western Asia (Anatolia) and Eastern Europe thus implying a continuous distribution range of this genus stretching through the middle latitudes of the Holarctic and likely marking the continental belt of temperate forests in late Early Miocene. Marmotines of North American origin document direct faunal communication between temperate faunas of the Old and New Worlds at that time.

First palynological data from the Amat and Plyavinsky Horizons of the Main Devonian field

Research subject. Spores of higher plants from the Early Frasnian deposits of the Main Devonian Field. Material and methods. The work is based on the biostratigraphic method with the following stages: determination of the taxonomic composition of palynospectra, substantiation of the host rocks age, and data correlation. Palynological analysis was conducted using an improved technique by I.Kh. Shumilov and O.P. Telnova, which produced positive results. Results. For the first time, spores of higher plants were found in the sections of the Amatsky and Plavinsky Horizons of the Main Devonian Field. The palynospectra of the Podsnetogorsk layers of the Amat and Snetogorsk layers of the Plyavinsky Horizons were described. The palynospectra of the Podsnetogorsk layers are correlated with the palynoassemblage from the upper part of the Timan, and the Snetogorsk layers are correlated with the palynoassembly of the Sargaev Horizons, established in the Timan-Pechora province. The identified palynospectra complement the associations of vertebrate and invertebrate fauna, as well as rare macroflora, previously studied in these sections. The palynospectra from the Snetogorsk beds are correlated with the palynoassemblage of the Cristatisporites deliquescens – Archaeoperisaccus mennerii regional zone of the Timan-Pechora province. The palynozone characterizes the stratigraphic interval corresponding to the rugosa–transitans conodont zones (middle–upper part of the Sargaev Horizon). Conclusions. The established palynoassemblage from the Snetogorsk layers corresponds to the middle part of the Sargaev Horizon – the stratigraphic interval of the rugosa conodont zone. For the first time, the conducted palynological studies established a binding between the regional stratigraphic unit of the Main Devonian Field and the standard conodont zone.

How many threatened lice are there? An approximation to the red list of the Spanish Phthiraptera

Although the idea of conserving parasites as part of biodiversity is not new, these in general and lice in particular, are not included in the threatened list of invertebrate fauna. Assuming that the conservation status of a lice species is similar to that of its host, the number of threatened lice within the Spanish entomofauna was estimated based on the known host-lice assemblages. The lice parasitizing many of the Spanish birds and mammals are unknown. Overall, I found 6 extinct (EX) species; 4 critically endangered (CR); 15 endangered (EN), 7 vulnerable (VU) and 1 species near threatened (NT), at regional level. Since the status of hosts varies through time and space, it, (together with those of their lice, must be periodically updated. In addition to a number of reasons that justify the conservation of parasites, lice deserve being conserved, particularly, because of their scientific value.

Assessment of the estuarine shoreline microplastics and mesoplastics of the River Itchen, Southampton (UK) for contaminants and for their interaction with invertebrate fauna

The presence of shoreline microplastics (1–5 mm) and mesoplastics (5–25 mm) in estuarine ecosystems is ubiquitous, but there remains little data on their composition, contamination status and ecological impacts. Chessel Bay Nature Reserve, situated in the internationally protected Itchen Estuary in Southampton, UK, has serious issues with shoreline plastic accumulation. In evaluating potentially adverse ecological impacts, the influence of quantities of shoreline microplastic (mp) and mesoplastic (MeP) material and adsorbed contaminants (PAHs and trace metals) on the biometrics and population dynamics of the burrowing supralittoral amphipod, Orchestia gammarellus, was assessed in this study. mp/MeP concentrations were variable in surface (0–42%: 0–422,640 mg/kg dry sediment) and subsurface horizons (0.001–10%: 11—97,797 mg/kg dry sediment). Secondary microplastics accounted for 77% of the total microplastic load (dominated by fragments and foams), but also comprised 23% nurdles/pellets (primary microplastics). Sorption mechanisms between contaminants and natural sediments were proposed to be the main contributor to the retention of PAHs and trace metal contaminants and less so, by mp/MeP. O. gammarellus populations showed a positive correlation with microplastic concentrations (Spearman correlation, R = 0.665, p = 0.036). Some reported toxicological thresholds were exceeded in sediments, but no impacts related to chemical contaminant concentrations were demonstrated. This study highlights a protected site with the severe plastic contamination, and the difficulty in demonstrating in situ ecotoxicological impacts.

Ecological attributes of aquatic invertebrates in two water turbidity scenarios in a lake of the Pantanal, Brazil

The objective of this work was to determine the taxonomic structure and Functional Feeding Groups (FFGs) of benthic invertebrates and their roles in two different water turbidity scenarios in a floodplain lake in the Pantanal wetland (Sinhá Mariana Lake, Barão de Melgaço, state of Mato Grosso). We studied the benthic invertebrate fauna at 18 sampling sites in periods of high turbidity (HT) and low turbidity (LT) during high water (HW) and low water (LW). We hypothesize that the structure of Chironomidae assemblages (species and functional feeding groups) varies between sites in Sinhá Mariana Lake, and the density and diversity attributes of species in this family and their functional feeding groups are reduced under increased turbidity. Depth, water temperature, turbidity, pH, pCO₂, water color, and organic matter content of the sediment were analyzed in each sampling site. Chironomidae presented higher density and diversity in periods of high water (HW) in sites with low turbidity water (LT). The dominance increased in periods of low water (LW). The main FFGs were represented by collector-gatherers, while the smallest groups corresponded to shredder-herbivores (50% and 9% of the total abundance, respectively). Collector-gatherers (Aedokritus sp., Chironomus strenzkei, Goeldichironomus petiolicola, G. maculatus, Beardius phytophilus), predators (Ablabesmyia gr. annulata, Labrundinia sp. and Cryptochironomus brasiliensis) and shredder-herbivores (Asheum sp., Polypedilum sp., Polypedilum gr. fallax) predominated in high water (HW) periods. A change in the community structure from the HW to LW was evidenced, characterized by the substitution of collector-gatherers for collector-filterers. Notodiaptomus deitersi (Crustacea) was dominant in LW (dominance index = 10.9) and Aedokritus sp. (Insecta) in HW (dominance index = 5.4). Water turbidity and the hydrological cycle are important factors determining spatial and temporal patterns in communities, particularly changes in FFGs. Changes in turbidity in different sites and periods alter the structure of trophic communities and lead to questions about the main drivers of communities in Pantanal wetlands as areas of high ecological relevance for maintaining biodiversity.

Occurrence of Hepatozoon in Some Reptiles from Brazilian Biomes with Molecular and Morphological Characterization of Hepatozoon caimani

Amphibians and reptiles represent a considerable proportion of the vertebrate fauna in Brazil. Different blood parasitic infections have been reported in these groups, such as Haemogregarina, Hepatozoon, Trypanosoma and microfilariae. However, insufficient research on interactions between these parasites and their hosts has been carried out in some regions of the country. Samples were collected from populations of wild herpetofauna in different microhabitats throughout Brazil, totaling 111 samples of reptiles from the states of Mato Grosso and Pernambuco. We used an integrative approach, with classical microscopy, morphometry and molecular analysis, in order to identify hemoparasites present in the analyzed fauna. Genomic DNA was extracted for the PCR protocol based on the 18S ribosomal RNA gene for Hepatozoon spp. A total of 53 positives were obtained with molecular screening (47.7%), all confirmed as Hepatozoon spp. using DNA sequencing. Among positive samples, 23 slides were examined, confirming the presence of Hepatozoon spp. in 91.3% of the smears. The phylogenetic analysis performed with sequences from 43 samples resulted in a tree containing several distinct clades. Sequences were generally grouped according to the taxonomic order of the host. Co-infections with microfilariae and Trypanosoma spp. were also found in microscopy analyses. This study describes the presence of Hepatozoon caimani in a new host species (Paleosuchus palpebrosus) that can be a paratenic host in the natural environment. The existence of parasitic co-infections in alligator species underscores the significance of recognizing the impact of infections by various parasitic taxa on the host populations.

Invertebrate fauna of the Albian–Lower Cenomanian deposits in the Fars and Isfahan provinces (Firuzabad and Fasakhod sections), Zagros Basin, Central Iran

The Albian- Cenomanian deposits of the Kazhdumi Formation at Zagros Basin (Firuzabad section and Central Iran (Fasakhod section), represents a carbonate sedimentary succession and contain rich and diverse invertebrate macro fauna. Detailed studies on about 200 specimens of invertebrate macro fauna revealed from two stratigraphic intervals led to recognition of 5 species of gastropods; (Liopeplum? sp., Columbellina sp., Cryptaulax? sp., Turritella? sp., Pleurotomaria sp.), 3 species of ammonites; (Knemiceras duberterti, Sphenodiscus sp., Knemiceras persicum), 10 species of bivalves assemblages; (Ceratostreon flabellatum, Cardium? sp., Exogyra (Costagyra) olisiponensis, Neithea (Neithea) quinquecostata, Trigonia sp., Buchia? sp., Cardium? sp., Pseudogyra sp., Ontaria? sp., Nucula? sp., Pleuromia? sp., 1 species of echinoids; Dorocidaris taouzensis with a prolific horizon of Notopocorystes xizangensis of raninoid crabs. The absence of large gastropods and bivalves fauna and abundance of suspension-feeders indicated instability of the substrate, shallow marine paleoenvironment.and a medium energy condition.

Environmental DNA-based biomonitoring of Cuban Crocodylus and their accompanying vertebrate fauna from Zapata Swamp, Cuba

Crocodylians globally face considerable challenges, including population decline and extensive habitat modification. Close monitoring of crocodylian populations and their habitats is imperative for the timely detection of population trends, especially in response to management interventions. Here we use eDNA metabarcoding to identify the Critically Endangered Crocodylus rhombifer and the Vulnerable C. acutus, as well as vertebrate community diversity, in Cuba’s Zapata Swamp. We tested four different primer sets, including those used previously in Crocodylus population genetic and phylogenetic research, for their efficiency at detecting crocodylian eDNA. We detected C. rhombifer eDNA in 11 out of 15 sampled locations within its historical geographic distribution. We found that data analyses using the VertCOI primers and the mBRAVE bioinformatics pipeline were the most effective molecular marker and pipeline combination for identifying this species from environmental samples. We also identified 55 vertebrate species in environmental samples across the four bioinformatics pipelines— ~ 85% known to be present in the Zapata ecosystem. Among them were eight species previously undetected in the area and eight alien species, including known predators of hatchling crocodiles (e.g., Clarias sp.) and egg predators (e.g., Mus musculus). This study highlights eDNA metabarcoding as a powerful tool for crocodylian biomonitoring within fragile and diverse ecosystems, particularly where fast, non-invasive methods permit detection in economically important areas and will lead to a better understanding of complex human-crocodile interactions and evaluate habitat suitability for potential reintroductions or recovery programs for threatened crocodylian species.

Fossil marine vertebrates (Chondrichthyes, Actinopterygii, Reptilia) from the Upper Cretaceous of Akkermanovka (Orenburg Oblast, Southern Urals, Russia)

Upper Cretaceous coastal marine deposits are widespread in the Southern Urals with a number of marine vertebrates previously reported from this region. However, previous studies on the vertebrate faunas in this region often lack detailed taxonomic descriptions and illustrations, rendering comparisons to other faunal assemblages difficult. A new diverse vertebrate assemblage comprising cartilaginous and bony fishes, as well as marine reptiles, is described here from the Orenburg region near Akkermanovka (Southern Urals, Russia). Thirty five taxa are identified, including three holocephalans (Elasmodus sp., Ischyodus yanschini, Chimaeroid indet.), two hybodontiform sharks (Meristodonoides sp., cf. Polyacrodus sp.), 17 neoselachians (Paraorthacodus cf. andersoni, Paraorthacodus sp., Synechodus sp., Cederstroemia nilsi, Acrolamna acuminata, Archaeolamna ex gr. kopingensis, Cretalamna sarcoportheta, Cretoxyrhina mantelli, Eostriatolamia segedini, E. venusta, Hispidaspis horridus, H. cf. gigas, Pseudocorax laevis, Pseudoscapanorhynchus compressidens, Scapanorhynchus rhaphiodon, Squalicorax kaupi, Ptychodus rugosus), a holostean (Lepisosteidae indet.), nine teleosts (Protosphyraena sp., Saurodontidae indet., cf. Pachyrhizodus sp., Pachyrhizodontidae indet., Enchodus petrosus, E. ferox, E. cf. gladiolus, E. spp., Alepisauroidei indet.), two plesiosaurs (Polycotylidae indet., Plesiosauria indet.), and one mosasaurid (Tylosaurinae indet.). Based on the faunal assemblage, a Santonian–?early Campanian age is proposed. Lamniform sharks are the best represented group in terms of taxic diversity and relative abundance, probably reflecting the peak in diversity this group experienced following the Cenomanian radiation in the Late Cretaceous. The faunal assemblage of Akkermanovka exhibits significant taxonomic overlaps with assemblages reported from Asia and North America, but not from Southern Hemisphere continents, indicating east–west dispersal of several marine taxa during the Late Cretaceous.

New record of two species of munidid squat lobster (Decapoda: Anomura) from the North-West Pacific off Japan.

Two species of munidid squat lobsters are newly reported from the North-West Pacific off Japan based on material collected by the recent cruise of R/V Kaimei (KM20-10C cruise) of the Japan Agency for Marine-Earth Science and Technology, exploring seamounts in the marine protected area (MPA): Gonionida kaimei n. sp. and Trapezionida psylla (Macpherson, 1994). Gonionida kaimei n. sp. closely resembles G. tangaroa (Ahyong, 2007) and G. rubrimana (Ahyong, 2007), but morphological characters and living colouration differentiate the new species from the latter two species. Genetic analysis using two molecular markers (mitochondrial COI and 16S rRNA genes) also supports the recognition of the new species. Trapezionida psylla has been recorded from the South-West Pacific, and thus the present material greatly extends the geographic range of the species to the North-West Pacific. The identity of the present specimens is also confirmed by the genetic data, as well as the morphological evidence. This study contributes to documenting the benthic invertebrate fauna of the Japanese MPA.

New data on Silurian (Llandovery) sinacanthids from Wuhan, South China and their biostratigraphic and paleobiogeographic implications

Sinacanthids are a group of Silurian spine-based mysterious taxa, probably representing a lineage of stem chondrichthyans. New sinacanthid fossils attributed to Sinacanthus wuchangensis, S. triangulatus, Sinacanthus sp., Neosinacanthus planispinatus, Tarimacanthus bachuensis, Eosinacanthus shanmenensis, and fin spine morphology 1, 2 and 3 are identified from the upper member of the Qingshui Formation and the Fentou Formation (Telychian, Llandovery) of Wuhan, South China. These sinacanthid fin spines are similar to those from the Rongxi Formation in northwestern Hunan and the Ymogantau Formation in the northwestern Tarim. This study provides further evidence for the presence of diverse sinacanthid faunas from the South China plate. As the part of the Zhangjiajie Vertebrate Fauna of China, they have great significance in the paleogeographic division of vertebrates and the regional stratigraphic division and correlation. The Silurian sinacanthids from China were mainly grouped into three assemblages, i.e., the Wentang/Tataertag assemblage (early Telychian), the Fentou/Ymogantau assemblage (middle Telychian), and the Maoshan assemblage (middle to late Telychian). In addition, the sinacanthids from the South China plate, Tarim plate, and Qiongzhong block belong to the Zhangjiajie Vertebrate Fauna and there was certain extent of migration of sinacanthids among these areas during the Telychian, Silurian.

Density and ecological drivers of free‐ranging cat abundance and activity in Madeira Island, Macaronesia

AbstractMammalian predators introduced to oceanic islands pose a significant threat to biodiversity and have led to numerous extinctions. Free‐ranging cats are particularly problematic due to their predatory habits and negative impact on conservation. However, there is limited information on the ecology and population status of free‐ranging cats in insular ecosystems, where they often represent the apex terrestrial predator. Using a peri‐urban protected area in the subtropical island of Madeira as a case study, we employed camera traps to assess the density of free‐ranging cats and investigate the ecological drivers influencing their abundance and activity in nonurban insular habitats. Based on 582 trapping‐nights, we identified 25 individual cats from 156 cat detections. Spatially explicit capture–recapture models revealed a density of 1.4 cats per km2. Cat activity was positively affected by both the proportion of rocky areas in the landscape and the distance to human resource subsidies, whereas no significant driver was found for abundance. Our results indicate that cats are highly abundant throughout the protected area and suggest that their core home ranges are associated with rocky terrain, away from the most humanized sections of the park. Free‐ranging cats do not appear to heavily rely on anthropogenic food sources, signaling that they may rely mostly on wild prey to fulfill their dietary needs. Their preference for rocky areas could be explained by the increased availability of shelter and prey, such as the Madeira wall lizard (Teira dugesii). Notably, cat abundance and activity were particularly high in the vicinity of the only known breeding colony of the locally threatened Manx shearwater (Puffinus puffinus) on Madeira Island. Our findings suggest that cats pose a significant threat to the native vertebrate fauna of the protected area and thus their management, particularly during the breeding season of the Manx shearwater, should be considered.