Small Mammal Assemblages Research Articles

Nonvolant Small Mammal (Rodentia and Didelphimorphia) Assemblages Structure in Areas Under Mining Impact in the Brazilian Amazon

Tropical forests are the most biodiverse ecosystems on Earth. Unfortunately, they are often degraded by large enterprises that convert large areas of continuous forest into forest mosaics or into d...

Isolated alpine habitats reveal disparate ecological drivers of taxonomic and functional beta-diversity of small mammal assemblages

The interpretation of patterns of biodiversity requires the disentanglement of geographical and environmental variables. Disjunct alpine communities are geographically isolated from one another but experience similar environmental impacts. Isolated homogenous habitats may promote speciation but constrain functional trait variation. In this study, we examined the hypothesis that dispersal limitation promotes taxonomic divergence, whereas habitat similarity in alpine mountains leads to functional convergence. We performed standardized field investigation to sample non-volant small mammals from 18 prominent alpine sites in the Three Parallel Rivers area. We estimated indices quantifying taxonomic and functional alpha- and beta-diversity, as well as beta-diversity components. We then assessed the respective importance of geographical and environmental predictors in explaining taxonomic and functional compositions. No evidence was found to show that species were more functionally similar than expected in local assemblages. However, the taxonomic turnover components were higher than functional ones (0.471±0.230 vs. 0.243±0.215), with nestedness components showing the opposite pattern (0.063±0.054 vs. 0.269±0.225). This indicated that differences in taxonomic compositions between sites occurred from replacement of functionally similar species. Geographical barriers were the key factor influencing both taxonomic total dissimilarity and turnover components, whereas functional beta-diversity was primarily explained by climatic factors such as minimum temperature of the coldest month. Our findings provide empirical evidence that taxonomic and functional diversity patterns can be independently driven by different ecological processes. Our results point to the importance of clarifying different components of beta-diversity to understand the underlying mechanisms of community assembly. These results also shed light on the assembly rules and ecological processes of terrestrial mammal communities in extreme environments.

Predictive sampling effort and species-area relationship models for estimating richness in fragmented landscapes.

Loss of habitat, specifically deforestation, is a major driver of biodiversity loss. Species-area relationship (SAR) models traditionally have been used for estimating species richness, species loss as a function of habitat loss, and extrapolation of richness for given areas. Sampling-species relationships (SSRs) are interrelated yet separate drivers for species richness estimates. Traditionally, however, SAR and SSR models have been used independently and not incorporated into a single approach. We developed and compared predictive models that incorporate sampling effort species-area relationships (SESARS) along the entire Atlantic Forest of South America, and then applied the best-fit model to estimate richness in forest remnants of Interior Atlantic Forest of eastern Paraguay. This framework was applied to non-volant small mammal assemblages that reflect different tolerances to forest loss and fragmentation. In order to account for differences in functionality we estimated small mammal richness of 1) the entire non-volant small mammal assemblage, including introduced species; 2) the native species forest assemblage; and 3) the forest-specialist assemblage, with the latter two assemblages being subsets of the entire assemblage. Finally, we geospatially modeled species richness for each of the three assemblages throughout eastern Paraguay to identify remnants with high species richness. We found that multiple regression power-law interaction-term models that only included area and the interactions of area and sampling as predictors, worked best for predicting species richness for the entire assemblage and the native species forest assemblage, while several traditional SAR models (logistic, power, exponential, and ratio) best described forest-specialist richness. Species richness was significantly different between assemblages. We identified obvious remnants with high species richness in eastern Paraguay, and these remnants often were geographically isolated. We also found relatively high predicted species richness (in relation to the entire range of predicted richness values) in several geographically-isolated, medium-size forest remnants that likely have not been considered as possible priority areas for conservation. These findings highlight the importance of using an empirical dataset, created using sources representing diverse sampling efforts, to develop robust predictive models. This approach is particularly important in geographic locations where field sampling is limited yet the geographic area is experiencing rapid and dramatic land cover changes. When combined, area and sampling are powerful modeling predictors for questions of biogeography, ecology, and conservation, especially when addressing habitat loss and fragmentation.

Invasive rodents and damages to food stocks: a study in the Autonomous Harbor of Cotonou, Benin

Description of the subject. Rodents may be major pests to crops and stored food, thus threatening food security. Among them, invasive species such as rats and mice are of particular concern since they are disseminated globally following international trade. We investigated the small mammal assemblage within the international seaport of Cotonou, Benin, in order to determine the relative importance and distribution of native vs invasive rodent species, as well as to evaluate the amount and associated costs of rodent-induced damages on imported/exported stored goods (here, rice). Objectives. Description of rodent assemblages within an African seaport, and evaluation of the associated damages on stored food stocks. Method. Rodent communities were described following trapping results while associated damages and costs were evaluated following a 25 days long monitoring campaign and subsequent economic estimation of loss. Results. Our results show that invasive mice and rats are, from far, the most impacting rodents in the storage warehouses, and that the associated economic losses are quite large. Moreover, we point towards a few environmental management procedures that may greatly reduce the impact of rodents on stored goods. Conclusions. Damages and costs due to invasive rodents within the Cotonou Harbor are so that they justify financial investment in rodent population control.

Combined palaeoecological methods using small-mammal assemblages to decipher environmental context of a long-term Neanderthal settlement in northeastern Iberia

Recurrent long- and short-term Neanderthal occupations occurred in the Abric Romaní rock shelter (Capellades, Barcelona, Spain) for more than 20,000 years. This provides an opportunity to enhance our understanding of the evolution of behavioral strategies of these human groups. The site has a long and high-resolution sequence with 17 levels completely excavated, 13 of which are presented in this work, from D to Q; ca. 40–60 ka. These levels have generated extensive research concerning Neanderthal hunting strategies, lithic production, and fire technology. Here is presented the evolution of palaeoenvironment under which these populations lived applying different methods of palaeoecological reconstruction based on small-mammal remains along the entire sequence. The study is completed with taphonomic analyses that locate the primary origin of their accumulation under the action of owls and describe a past humid fossiliferous microenvironment where intense human occupation occurred. Oxygen isotope analyses were performed on rodent incisors from the richest levels (D, E, N and O), in order to reconstruct the past air temperatures. The medium to low intra-level ranges of oxygen isotopic values indicate a period of preferential accumulation moment of small mammals, which is likely related to spring-summer predator activity. Throughout the sequence, the landscape evolution is marked by an extended forestall cover and abundant water resources, both integrated in a patchy landscape. Climatic conditions were globally cooler and slightly wetter than present, but rather stable across the sequence. The greater relative presence of mid-European small-mammal species and the estimated lower palaeotemperatures correspond to relatively cooler episodes, such as stadial events, in levels E and O. However, certain discrepancies in palaeotemperature estimations are detected between oxygen isotopic analyses and other methods based on species occurrence. Northeastern Iberia environmental conditions related to Mediterranean climate provide a favorable MIS 3 scenario compared to European higher latitudes. Indeed, the milder glacial fluctuations detected within the Abric Romaní site are coeval to other Iberian Middle Palaeolithic sites with long-term occupations and allow these human groups to incorporate this region for millennia in their migration routes.

A cave lion (Panthera spelaea) skeleton from Torca del León (NW Iberia): Micromammals indicate a temperate and forest environment corresponding to GI-11 (MIS 3)

The Torca del León site (Asturias, NW Spain), discovered in 2014, provided an interesting fossil assemblage including a P. spelaea partial skeleton and a rich micro-mammal community with palaeoenvironmental significance. The bone accumulation was formed in a karstic cave that acted as a natural trap, as indicated by the geomorphology of the cavity (connected to a 16 m deep shaft) and the lack of signs of human or carnivore activity on the bones.The large-mammal assemblage is composed of carnivores, of which the most striking is the partial skeleton of the cave lion, an exceptional find for this region, which allowed a detailed comparative study. Its skull and teeth retained features of systematic relevance, which agree with its ascription to P. spelaea. Sexing of the specimen points to it possibly being from a male, whose body weight was estimated at 360 kg. Other identified large mammals in the site include P. pardus and Canis lupus.The rich small mammal assemblage, comprising 14 taxa, allowed inferring that the environment during site formation corresponded to a mature forest developed under humid and temperate conditions, located at just 15 km from the glacial fronts of the Cantabrian Mountains. AMS dating yielded 43.0 ± 0.5 cal ka BP, coinciding with Greenland Interstadial GI-11, a warming event poorly known in NW Iberia, coeval with the onset of the regional glacial retreat occurred after the local glacial maximum of ∼45 ka. This episode is also coeval with the Middle to Upper Paleolithic transition in Northwestern Iberia.

Small mammal assemblage composition and habitat associations across an elevational gradient in southern California

AbstractElevational gradients coincide with expansive climatic gradients and diverse plant and animal communities. We evaluated the small mammal assemblages in eight distinct vegetation types across an elevational gradient in southern California, the Deep Canyon Transect, to determine how assemblage composition changes across the gradient and to identify species with similar habitat associations. Livetrapping efforts (4,800 trap-nights) yielded 1,097 captures of 713 individuals, representing 14 heteromyid and cricetid species. Heteromyids dominated the six lower-elevation vegetation types (< 1,300 m a.s.l.), whereas cricetids dominated the upper end of the gradient. Richness and diversity exhibited bimodal responses to elevation, which do not conform to mid-domain effect null predictions. Canonical correspondence analysis revealed that 75% of the variation in small mammal abundances was explainable by habitat characteristics, and cluster analysis grouped small mammals into three ecologically distinct groups based on their habitat associations. One contained only Chaetodipus penicillatus, while the others were comprised of low- and high-elevation species, respectively. The low-elevation species exhibit unusual levels of sympatry (and syntopy) among closely related species of pocket mice (Chaetodipus). Further efforts should investigate the mechanisms of coexistence for Chaetodipus species with nearly identical associations and seasonal effects on richness and diversity. Repeated surveys of entire gradients such as the Deep Canyon Transect will help refine our understanding of temporal dynamics of community assemblage and diversity.

Competencia interespecífica y demografía de pequeños mamíferos en hábitats lineales

Fil: Serafini, Vanesa Natalia. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Instituto de Ciencias de la Tierra, Biodiversidad y Ambiente - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Ciencias de la Tierra, Biodiversidad y Ambiente; Argentina

Palaeontological description of Nizhneirginsky Grotto Upper Holocene sediments (Ufa Plateau, Fore-Urals) with taphonomic and palaeoenvironmental remarks based on bird and small-mammal assemblages

Mammal and bird bone remains from Upper Holocene sediments at the Nizhneirginsky Grotto were studied. Nizhneirginsky Grotto is located in the northern part of the Ufa Plateau in the Middle Fore-Urals. The sequence of deposits contains three layers which have been accumulating during the last 4150 years. Identified mammal elements include 9839 bone remains of 29 species belonging to five orders, i.e., Eulipotyphla (435), Chiroptera (1608), Lagomorpha (52), Rodentia (7688), and Carnivora (56). Recovered bird remains include 1946 bones of 38 species. Most identified species currently inhabit the Nizhneirginsky Grotto area. The analysis of alterations in the first lower molars of arvicoline rodent species caused by the digestion showed that eagle owl (Bubo bubo, Linnaeus, 1758) is the most possible agent responsible for the accumulation of small mammal assemblages in the grotto sediments. An unusually high number of birch mouse fossils was noted over the entire sediment section of the grotto (MNI on average by layers is 8.1–15.4%). This phenomenon, probably, has a taphonomic origin and is associated with the predation activity of mustelids. Palaeoenvironmental analysis of small mammal assemblages based on the habitat weighting method showed the predominance of open landscapes and woodlands around the grotto during the Late Holocene. This landscape did not change in the last 4150 years. The connection of the history of the yellow-necked mouse in the northeast of its modern range with the palaeogeographic events of the second half of the Holocene was established. The material from the sediments of the Nizhneirginsky Grotto shows that the species was common in the northern part of the Ufa Plateau, in the Irgina River valley, in the period of 4150-3100 cal BP, which coincides with the maximum distribution of broad-leaved trees in the Fore-Urals during the mid-Subboreal thermal maximum (SB-2; 4200-3200 BP). Pika's (Ochotona, perhaps O. pusilla, Pallas, 1769) sinister mandible was found among osteological material from the upper part of layer 2 which dates to 710 ± 20 cal BP (1240 ± 20 cal AD). This is the first find of the pika's remains of such late age in the Middle Urals and in adjacent territories. The species was common in the northern part of the Ufa Plateau during Late Pleistocene and Early Holocene. Steppe pika is now disjunct from the Nizhneirginsky Grotto by approximately 200–300 km to the south and to the south-west. O. pusilla probably inhabited the valley of the Irgina River as a relic of the Late Pleistocene and Early Holocene faunas as early as 12th and 13th centuries AD.

The age and paleoenvironment of a late Miocene floodplain alongside Lake Pannon: Rodent and mollusk biostratigraphy coupled with authigenic 10Be/9Be dating in the northern Danube Basin of Slovakia

We present new age constraints for the late Miocene Volkovce Formation of Slovakia, alluvial facies that accumulated adjacent to Lake Pannon. Facies analysis and authigenic 10Be/9Be dating was undertaken at the Bernolákovo and Triblavina localities while the latter outcrop also yielded additional small mammal and mollusk assemblages as well as remains of flora. The results of seven radiometric dating ages yielded a weighted mean age of 9.65 ± 0.61 Ma for the Triblavina outcrop and 8.85 ± 0.32 Ma for the Bernolákovo outcrop. The small mammal assemblage at the Triblavina outcrop is indicative of the lowermost MN11 zone, which in the Western European standard definition suggests an age of <8.9 Ma. The ~0.1 Ma inconsistency between absolute dating and biostratigraphic dating at the Triblavina outcrop might be explained either by the variation of initial 10Be/9Be ratio in the depositional environment or/and by diachronous development of the mammal faunas across the Europe. The mollusk assemblage at this outcrop indicates the paleoenvironment of freshwater lakes affected by rivers with evidence for a nearby riparian forests; it may be roughly correlated with Papp's lithostratigraphic units G and H defined for the Pannonian stage in the Vienna Basin. Our results provide a detailed insight to the late Miocene stratigraphy and terrestrial environments alongside the Lake Pannon shoreline.

Rodents and other terrestrial small mammals from Kanapoi, north-western Kenya

Excavations at Kanapoi in north-western Kenya have yielded the most numerically abundant and taxonomically diverse early Pliocene (4.19 Ma) terrestrial small mammal assemblage known from Kenya. A minimum of 15 species are reported, including soricids, sengis, leporids, and rodents: all taxa are referable to extant genera, with the exception of the murine rodent, Saidomys. The majority of the terrestrial small mammals are derived from a bone bed at Nzube's Mandible Site, closely associated with the holotype mandible of Australopithecus anamensis. A smaller number were surface-collected or obtained from screening at several other sites, including the Bat Site. Most small mammals from Nzube's Mandible Site and the Bat Site likely represent prey accumulated as regurgitated pellets from owls, in particular barn owls or giant eagle owls. The small mammal fauna is dominated by the spiny mouse, Acomys: the next most commonly recovered taxa are the multimammate mouse, Mastomys, and the African gerbil, Gerbilliscus. Comparisons of the Kanapoi fauna to other eastern African late Miocene-Pliocene (and one Pleistocene) faunas at the generic level suggest the greatest similarity is to Lemudong'o, Kenya, and Omo B and Aramis, Ethiopia. Further similarities with other localities such as Laetoli, Tanzania, and Hadar, Ethiopia, suggest the existence of a corridor for dispersal along the East African Rift Valley between Ethiopia, Kenya, and Tanzania in the early Pliocene. Further comparisons of the relative abundances of individuals in different families (or subfamilies) emphasize the distinctiveness of the Kanapoi small mammal fauna. The Kanapoi fauna is likely derived from a heterogeneous but relatively arid environment.

The Upper Pliocene – Quaternary geological history of the Shirak Basin (NE Turkey and NW Armenia) and estimation of the Quaternary uplift of Lesser Caucasus

Stratigraphy, structure, and tectonics of the Turkish part of the intermontane Shirak Basin and the adjacent Susuz Basin were studied based on methods of structural geology, geological and geomorphological correlation, paleontology, paleomagnetism, and archaeology. For the first time, the Pliocene-Quaternary stratigraphy and tectonics of the western Turkish and eastern Armenian parts of the Shirak Basin were correlated. Sedimentary cover of the western part of the basin consists of four units: the Lower Akchagylian (Piacenzian) marine deposits, Karakhach, Ani, and Arapi lacustrine-alluvial units. The Upper Pliocene age of the former formation in the Demirkent section is evidenced by normal palaeomagnetic signature and dinocysts of the Akchagylian aspect with some forms known to have a highest stratigraphic datum near the Pliocene–Quaternary boundary. The age of the Karakhach unit is estimated at 1.9–1.7 Ma based on similar geomorphological position and composition with corresponding deposits in Armenia, normal polarity, and a record of the Early Palaeolithic artefact. The dating of the Ani unit to the Calabrian, and the Arapi unit to the lower Middle Pleistocene is evidenced by assemblages of molluscs and small mammals, Acheulian artefacts, palaeomagnetic data, and geomorphological position similar to the correlated sedimentary sequences in the Armenian part of the basin.The level of the Akchagylian brackish water basin at the Neogene–Quaternary boundary (2.58 Ma) was close to the recent oceanic level. The recent altitude of the top of the Lower Akchagylian deposits in the Demirkent section is 1565 m. This defines the average rate of the Quaternary uplift in this part of Lesser Caucasus at 0.6 mm/year. The Shirak Basin is bounded and ruptured by fault and flexure-fault zones. Because of offsets on the Çamuşlu and Akhuryan zones, the central part of the northern Shirak Basin is subsided relative to the Demirkent section at 130–165 m. The movements in the Çarçioğlu zone caused a 100–120 m rise of the Ani unit surface in the Susuz Basin relative to the adjacent part of the Shirak Basin. The north-western border of the Susuz Basin is uplifted on the Sarikamiş fault zone. Thus, the Quaternary uplift ranges near 0.6 ± 0.1 mm/year. To the north of the Shirak Basin, in the Upper Akhuryan and Lori Basins and the Debed River valley, the rate of uplift during 0.65–0.6 Ma is estimated at about 1 mm/year and the adjacent Bazum and Javakheti Ridges rose more intensively. Therefore, the uplift could accelerate during the time interval of 0.65–0.6 Ma.

Long-term impact of agricultural practices on the diversity of small mammal communities: a case study based on owl pellets.

Small mammals have been seldom used as indicators of biodiversity responses to environmental changes, probably because their long-term population trend in a given area is not easy to monitor. To assess the impact of agricultural intensification in a protected area of northern Italy, we compared the composition of its small mammal communities, as assessed in 1994-1995 and 2015-2016 by the analysis of owl pellets (N = 265 and 302, respectively), which provides an effective and affordable method for assessing changes in the diversity and structure of small mammal assemblages over time. We recorded a sharp reduction in the frequency of occurrence of shrews (Sorex spp. and Crocidura spp.), which were replaced by generalist/anthropophilic rats (Rattus norvegicus) and house mice (Mus domesticus). Overall richness and diversity of the community varied only slightly, while trophic level and functional diversity indices clearly reflected the decline of the predator-level fraction of the community. We could reliably exclude both broad-scale land use- and climate changes as drivers of variation in the composition of small mammal communities and ascribe the decline of insectivores to changes in agricultural practices, namely the increase in cover of maize fields and spread of both herbicides and insecticides. Our results are consistent with the general opinion that crop specialization and increasing chemical inputs reduce the diversity and abundance of invertebrate prey, with bottom-up effects on higher trophic levels.

Quaternary evolution of the Suluova Basin: implications on tectonics and palaeonvironments of the Central North Anatolian Shear Zone

The Suluova Basin is a prominent member of the wide transtensional Amasya Shear Zone located at the central part of the North Anatolian Shear Zone. This basin is crucial and provides well-resolved data to understand the evolution of transtensional tectonic zones as well as the morphological and paleoenvironmental changes of North Anatolia during the Quaternary. Analysis of detailed stratigraphical sections, faulting data, and mammal paleontology reveals that the Suluova Basin has started to evolve as a closed half-graben along the NW–SE-trending, SW-dipping basin bounding fault zone with normal slip in the early Quaternary. Initial sedimentation mode of the basin was dominated by alluvial fan facies associations. Progressive basin subsidence resulted in an expansion of a freshwater lake at the basin depocenter as faults propagated westwards. Further extensions in the basin were caused to initiate the E–W-trending southern tectonic boundary. Newly created accommodation space hosted a vast freshwater lake during the Calabrian (∼1.8–0.78 Ma) acting as a refugia for a rich faunal assemblage of large and small land mammals. The conditions prior to the onset of Middle Pleistocene (MIS19, ∼0.79 Ma) is marked with increasing regional erosion where paleo-Lake Suluova was captured by the regional river system. Synchronously, the next phase of the shear zone formation was introduced with E–W-trending dextral and NE–SW-trending sinistral strike-slip faults, cross-cutting the former basin structure, forming new depocenters. These faults are still active with noticeable seismic activity and comprise future risks for the major cities of the region.

New data on the introduction and dispersal process of small mammals in southwestern Europe during the Holocene: Castillejo del Bonete site (southeastern Spain)

In the Mediterranean realm, the development of navigation techniques by humans during the Mesolithic and the Neolithic favoured the dispersal of some small mammal species from Africa and the Levant into the European continent. Many details of this process still remain unclear such as the exact date of first arrivals of each species or how their dispersal into southwestern Europe occurred. In such a context, the new site of Castillejo del Bonete (southeastern Spain), provides exceptional information thanks to its rich microvertebrate assemblage. Over 8000 remains of small mammals have been identified in this site, belonging to eleven species. Radiocarbon dating performed directly on a specimen has given a date of 3819–3615 cal. BP. Thus, the small mammal assemblage of Castillejo del Bonete provides new evidence to reconstruct the biogeographical history of some small mammals of recent introduction in western Europe.The presence and relative abundance (12.45% of MNI) of the Western Mediterranean mouse (Mus spretus) is particularly interesting, since there are very few sites of this age in Iberia where its record can be considered reliable. A critical review of Mus species occurrences presented in this paper suggests that the Western Mediterranean mouse did not colonize southwest Europe before the Late Neolithic. Additionally, the absence of both the black rat (Rattus rattus) and the Etruscan shrew (Suncus etruscus) in this rich and diverse assemblage is in concordance with previous hypothesis which support the idea that the Iberian Peninsula was colonized by these two species on a more recent date.

Exotic Pinus radiata Plantations do not Increase Andes Hantavirus Prevalence in Rodents.

Andes south virus (ANDV) is the etiologic agent of hantavirus cardiopulmonary syndrome (HCPS) in Chile and southern Argentina. Farm and forestry workers have been identified as a group at high risk of acquiring HCPS caused by ANDV due to their close exposure to rodents or their secretions in rural areas. Therefore, investigation on the effect of landscape composition on ANDV in wild rodents becomes relevant for disease prevention and control. In this study, we analyzed the influence of Monterey pine (Pinus radiata) plantations, an important monoculture in the global forest industry, on small mammal assemblage and on ANDV seroprevalence and abundance of seropositive rodents from central Chile. Small mammals were sampled seasonally during 2years in native forests, adult pine plantations and young pine plantations. A total of 1630 samples from seven rodent species were analyzed for antibody detection. ANDV seroprevalence and abundance of seropositive rodents were significantly higher in the native forest compared to pine plantations. Furthermore, Monterey pine plantations decrease the abundance and relative abundance of Oligoryzomys longicaudatus (the principal reservoir of ANDV) and do not change sex ratio and distribution of age classes of this rodent species, which are variables that are important for ANDV transmission. Our findings indicate that Monterey pine plantations would not pose a higher risk of human exposure to ANDV compared to the temperate native forest. Our results can be useful for hantavirus risks assessment in human-dominated areas where ANDV is endemic.

The Ecology and Phylogeny of Hosts Drive the Enzootic Infection Cycles of Hantaviruses

Hantaviruses (Family: Hantaviridae; genus: Orthohantavirus) and their associated human diseases occur globally and differ according to their geographic distribution. The structure of small mammal assemblages and phylogenetic relatedness among host species are suggested as strong drivers for the maintenance and spread of hantavirus infections in small mammals. We developed predictive models for hantavirus infection prevalence in rodent assemblages using defined ecological correlates from our current knowledge of hantavirus-host distributions to provide predictive models at the global and continental scale. We utilized data from published research between 1971–2014 and determined the biological and ecological characteristics of small mammal assemblages to predict the prevalence of hantavirus infections. These models are useful in predicting hantavirus disease outbreaks based on environmental and biological information obtained through the surveillance of rodents.

Environmental and climatic context of the hominin occurrence in northeastern Italy from the late Middle to Late Pleistocene inferred from small-mammal assemblages

The environmental and climatic evolution of the late Middle Pleistocene to Late Pleistocene of the northeastern Italy is determined for Marine Isotope Stage 7 (MIS 7) to MIS 3 on the basis of a study of the small-mammal (insectivore, bat and rodent) assemblages. This paper provides a synthesis of three previously published and one unpublished sets of environmental and climatic data from the Middle to Upper Palaeolithic sites of Grotta Maggiore di San Bernardino, Grotta minore di San Bernardino, De Nadale cave and Fumane cave, all of which are located in northeastern Italy. Using the habitat weighting method and the bioclimatic model to reconstruct the environment, temperature and rainfall, the results show great variability in the landscape and climate of the area. However, the various layers from the studied sites in which the human presence is more intense coincide with landscapes dominated by woodland formations in mild climatic conditions. A comparison of our results with those from other sites with studies of small mammals in Greece, Italy, southern France and the Iberian Peninsula reveals the same pattern, showing that the hominins that inhabited the western Mediterranean region in the late Middle Pleistocene and Late Pleistocene were closely related to forested areas.

Amidst wind, sand and raptors. Small mammal bone remains recovered in open-air archaeological sites from the Monte Desert in Central Western Argentina: taphonomic and palaeoenvironmental implications

The distinctive characteristic of the Monte Desert, the most arid rangeland of Argentina, is reflected in the varied composition of its small mammal fauna. The present study analyses the taphonomic features and the palaeoenvironmental implications of small mammal bone and tooth accumulations recovered in open-air archaeological sites from the Monte Desert plains of northern Mendoza (Central Western Argentina) in the South American arid diagonal. In order to identify the agents responsible for such accumulations relative abundance trends, bone breakage patterns and digestive corrosion were evaluated. The action of postdepositional processes, like weathering and trampling, also were analysed. Taphonomic results allowed the detection of avian raptors—owls in particular—as the principal accumulating agents of small mammal bone and tooth accumulations of open-air archaeological sites from the Monte Desert. In order to make palaeoenvironmental inferences, the taxonomic structure of archaeological and modern small mammal assemblages was analysed and compared, added to the evaluation of taphonomic dynamics in the archaeological sites. The taxonomic composition of archaeological assemblages differed from that of the current assemblages from the study area. Thus, an extinct species (Holochilus lagigliai) and a little-known species highly adapted to desert environments (Tympanoctomys barrerae) were detected in the archaeological record. Recent pellet samples showed major proportions of opportunistic and generalist species as well as the presence of an exotic species (Mus musculus). The general impoverishment of current small mammal assemblages in comparison with past ones (e.g. richness, diversity and evenness) could be attributed to the deep impact of the anthropic perturbations generated by economic activities since the arrival of European conquerors ca. 500 years BP. Small mammal archaeological assemblages could indicate a scenario of greater environmental heterogeneity during the Late Holocene than in the present, and thus, greater availability of patch resources in the landscape.

Altitudinal variation of community metrics in Italian small mammal assemblages as revealed by Barn Owl (Tyto alba) pellets

A databank on the pellets of a widespread owl species (the Barn Owl, Tyto alba) was used in order to evaluate the differences in taxonomical composition and community metrics of small mammals (Rodentia and Soricomorpha) along an altitude gradient in Italy. The databank consisted of data from 292 sites, with altitudes ranging between −6 and 1292 m a.s.l. GLM models showed that the number of Rodentia species decreased significantly with elevation gradient, but increased significantly in Soricomorpha. Although there was no overall effect of the altitude on the number of species of Rodentia + Soricomorpha pooled, when we focused only on the central Apennine sites, there was a marginally significant negative correlation between number of species and altitude. There was also a significant increase in abundance with elevation in Soricinae and a significant decrease of abundance with elevation in Crocidurinae. Concerning the smallest sized Soricomorpha, there was a gradual substitution effect of one species (Suncus etruscus) with another (Sorex minutus) with elevation increases, and a logistic regression model revealed that elevation negatively affected the probability of presence of S. etruscus whereas it affected positively that of S. minutus. We think that the decrease in number of species of Rodentia with altitude may depend on the higher rate of agricultural land existing at lower elevations in Italy. The overall pattern of Soricomorpha would depend on the dominance of Soricinae species over the Crocidurinae (in terms of both number of species and relative abundance per site), with the Soricinae being more linked to temperate bioclimates than the Mediterranean-bioclimate-linked Crocidurinae.