Small Mammal Associations Research Articles

Arvicolinae rodents of Galería de las Estatuas (Sierra de Atapuerca, Burgos) and insights into MIS 5- to −4 climatic conditions in Northern Iberia

Well-dated Middle Palaeolithic sequences that lie beyond the limit of radiocarbon dating (i.e., >50,000 years ago) are critical for understanding the long-term palaeoecological changes that took place during Neandertal occupation of Europe and the Iberian Peninsula. Among the two pits excavated in Galería de las Estatuas site, GE (Sierra de Atapuerca, Burgos, Spain) represents such sequence, having been previously dated using a combination of single-grain optically stimulated luminescence (OSL) and U-series. This site is one of the few across Eurasia to have yielded both Neandertal remains and genetic evidence of Neandertal population replacements during marine isotope stage (MIS) 5 to the beginning of MIS 4 (120,000 to 70,000 years ago). Understanding the prevailing climatic and environmental conditions during the period of Neandertal occupation is therefore of great importance. Small mammal remains are one of the best proxies to interpret past environmental and climatic changes, and among these, the Arvicolinae species (Cricetidae, Rodentia) are particularly useful.Here we provide a revision of the small mammal associations at both Galería de las Estatuas pits undertaking detailed study of Arvicolinae species composition in both excavation pits. Additionally, we present new single-grain OSL dating results to refine the existing chronostratigraphic framework and better contextualise the past climatic changes inferred from the small mammal record. Our results indicate that the lower levels were formed in cold-temperate conditions, with a predominance of an open landscape and Atlantic-type climatic regime. Progressively upward through the sequences, we observe warmer and more humid conditions, with a stronger Mediterranean climate regime and increased development of forest areas, although still with a predominance of open meadows. Finally, both sedimentary sequences seem to end with a deterioration of these climatic conditions, and show a drier environment, dominated by open landscapes and a return to an Atlantic climatic regime. We conclude that at least two marked climatic changes can be identified at each pit (GE-I and GE-II), from MIS 5.4 through to the beginning of MIS 4, by studying the small mammal record together with OSL dating.

Environmental and climatic inferences for Marine Isotope Stage 2 of southern Belgium (Meuse valley, Namur Province) based on rodent assemblages

The environmental and climatic conditions of the Late Pleistocene of Southern Belgium are here determined for the final part of Marine Isotope Stage 3 (MIS 3) and for MIS 2 on the basis of a study of rodent assemblages. This paper provides a synthesis of several sets of environmental and climatic data from Late Pleistocene sites, all of which are located in southern Belgium. One has previously been published (Caverne Marie-Jeanne), and seven are unpublished (Cavernes de Goyet, Trou des Nutons, Trou du Frontal, Trou de Chaleux, Grotte la Chefalize, Trou du Chêne, and Trou du Sureau). The habitat weighting and quantified ecology methods are applied to rodent material housed in the Royal Belgian Institute of Natural Sciences (RBINS, Brussels), and previous radiocarbon dates are updated, in order to reconstruct past environments. Among all the sites under analysis, the quantified ecology method shows that Trou de Chaleux corresponds to the coldest temperatures and lowest precipitation. Trou de Chaleux, with a chronology between ca. 15,964–14,014 cal yr B.P., could probably be placed in Greenland Stadial 2 (GS2) or Heinrich Event 1 (HE1). It has a rodent assemblage associated with a predominance of open dry and rocky formations, the most abundant species being the collared lemming and the narrow-headed vole. These data are found to coincide with previous studies carried out on the large-mammal, herpetofaunal, and avifaunal associations of the site, as well as on small-mammal associations from other sites in southern Belgium with similar chronology, such as Grotte Walou. Taken together, this indicates that these latest Pleistocene intervals in southern Belgium were characterized by harsh climatic and environmental conditions. In contrast, the other assemblages under study yielded much more heterogeneous results, frequently inconsistent with an attribution to the Pleistocene. This is likely to be a result of their admixture with Holocene material due to recent intrusions.

Small mammal associations with habitat composition, configuration, and management in tallgrass prairies: a review

Abstract Tallgrass prairie is among the most threatened ecosystems but is often fragmented and surrounded by human‐modified landscapes. Small mammals are integral components of tallgrass prairies. However, little is known about how landscape composition, configuration, and management impact small mammals in tallgrass prairies. We conducted a systematic literature review to identify species‐specific and community associations with three broad topics: landscape composition, landscape configuration, and management practices. We identified 61 studies that assessed our variables of interest. We categorised the location, species assessed, variables monitored, and results by species and for the community. The majority of studies (64%) were conducted in two states, Illinois and Kansas. Deer mice (Peromyscus maniculatus), prairie voles (Microtus ochrogaster), and white‐footed mice (Peromyscus leucopus) showed specific associations with landscape variables, with deer mice preferring bare ground and recently burned plots, and prairie voles preferring thatch and negatively associated with prescribed fire. White‐footed mice were frequently associated with wooded areas. Small mammal biodiversity was positively associated with patchy habitats containing greater diversity in vegetative composition and management regime. Management and land composition were both relatively well studied for several species; habitat configuration was understudied. We identified significant gaps in our understanding of small mammal landscape ecology in tallgrass prairies. With tallgrass prairie restoration a growing trend in this region, a greater understanding of drivers of small mammal populations will be crucial to successful restoration efforts. Future research should focus on understudied areas and species, and examine how habitat heterogeneity impacts small mammal biodiversity.

Chronological context, species occurrence, and environmental remarks on the Gelasian site Pedrera del Corral d’en Bruach (Barcelona, Spain) based on the small-mammal associations

ABSTRACT Here we present the results of a study of the small mammal assemblage recovered from a now disappeared karstic fissure located in a quarry called ‘Pedrera del Corral d’en Bruach’. The site was located at 330 m a.s.l. in the Garraf Massif, ca. 20 km south of Barcelona. An archaeological rescue excavation was conducted in 2006 by the Grup de Recerca del Quaternari, focusing on sieving the sediments that had accumulated at the foot of the quarry face. Fortunately, some faunal remains and sediment were recovered, which were later processed and sorted. Two hundred and seventy small mammal remains were identified at genus or species level, bringing to light 15 taxa. The assemblage is typical of the Mammal Neogene 17 (MN17) biozone, placing this site in the Gelasian stage of the Early Pleistocene. It is noteworthy that the first record of the glirid Glirulus pusillus in Iberia is documented. Based on the small mammals identified, the surrounding environment of the Garraf Massif is judged to have been characterised by open forest landscape and more humid environmental conditions than nowadays. Finally, the site provides a remarkable contribution to what is known of the Iberian small mammals of this time period.

Late Pleistocene Palaeoenvironmental Variations from Marine Isotope Stages 5 and 4: Small Mammals at Artazu VIII Site (Arrasate, Northern Iberian Peninsula)

Sites corresponding to Marine Isotope Stage MIS 5c and MIS 4 like Artazu VIII, with a continental record but no hominin imprints or carnivore activities, are very scarce in the Iberian Peninsula. The Artazu VIII cave fill (Arrasate, northern Spain) was discovered in 2013 and is presented here for the first time, including detailed stratigraphic and sedimentological descriptions of the differentiated 12 levels, as well as an ordered chronology of most levels, covering at least 36.000 years. In addition, the small mammal assemblage yielded a total of 8,129 identifiable skeletal remains corresponding to 14 taxa. The conditions inferred from the ecological preferences of the small mammal associations have been correlated with four different stages and substages from MIS 5c to MIS 4 in which the woodland mass expanded and retreated, depending on the relative temperature and humidity in each period. Finally, considering the species variability and estimated palaeoenvironment, a comparison with the NGRIP δ18O curve and other sites with the same chronology has been performed, showing that Artazu VIII is one of the few deposits attributable to the Marine Isotopic Stages previously mentioned and the only one that correlates to the Greenland Interstadial 18 from the Iberian Peninsula.

New bioclimatic models for the quaternary palaearctic based on insectivore and rodent communities

Mammal remains, preserved in archaeological and palaeontological deposits, are commonly used to reconstruct past terrestrial climates and environments. Here we propose new species-specific models for Bioclimatic Analysis, a palaeoclimatic method based on a climatic restriction index for each mammal species, discriminant analysis, and multiple linear regressions. Our new models are based on small mammal associations, particularly insectivores and rodents, from Quaternary paleoarctic contexts. A dataset including new localities and an updated taxonomy was constructed in order to develop two approaches, the first using only Rodentia, the second based on associations including both Rodentia and Eulipotyphla. Both approaches proved to be reliable for inferring both climate zone and quantifying temperature, precipitation, and seasonality. Rarefaction analysis revealed these new models to be reliable even when a substantial percentage of species from the original palaeocommunity was absent from the fossil site. Application of these new models to small mammal associations from two sequences (Balma de l'Abeurador, France and El Mirón, Spain) spanning from the Last Glacial Maximum to the Holocene are consistent with the primary climatic changes recorded by regional Pyrenean proxies and showed an increase in mean annual temperature of between 3 and 5 °C.

Updating the Europe–Africa small mammal exchange during the late Messinian

AbstractAimThe Messinian salinity crisis (MSC) was an extraordinary geological event that affected the whole Mediterranean region as well as the global marine circulation between 5.97 and c. 5.33 Ma. One of its most direct effects was the emersion of land masses and the subsequent establishment of land bridges that led to common terrestrial faunal exchanges. However, the details of the onset of these exchanges have been a matter of controversy. New findings from southern Iberia of small mammal remains with African similarities have enabled us to review the Messinian faunal exchanges in the Mediterranean region.LocationMediterranean region.MethodsSmall mammal remains with African similarities from two new southern Iberian sites were studied. The small mammal associations of eight Miocene–Pliocene North African sites were also reviewed.ResultsTwo taxa with African similarities were identified at the Iberian study sites: Debruijnimys almenarensis and a Ruscinomys‐like form (cf. Ruscinomys) with a strong spur in the lingual lobe of the anterocone in the M1, a feature observed in North African Ruscinomys and eastern Mediterranean Byzantinia. The taxonomic status of some North African species and/or genera, such as Castillomys, Occitanomys and Prolagus, should be revised according to the new phylogenetic relationships established in European faunas.Main conclusionsTwo hypotheses can be proposed for the origin of the African Ruscinomys: (1) among the Iberian Ruscinomys or (2) from the eastern Mediterranean Byzantinia. Our data, currently from only a few, albeit significant, taxa, tend to support an Iberian origin. The discussion presented in this paper suggests an age near the closure of the last Betic Gateway (c. 6.18 Ma) for the first small mammal exchange between Africa and Europe, as well as a single migratory wave of small mammals, filtered by their ecological preferences from this point until the end of the MSC.

Small mammals from the Strashnaya cave (Northwest Altai, West Siberia, Russia)

A sequence of small mammal associations has been studied from the Paleolithic site of Strashnaya cave (Altai Mountains, West Siberia, Russia). The total faunal composition includes 45 species of rodents, bats, insectivores, and lagomorphs. The dominant groups in each of 10 layers that included small mammal remains are rock voles, grey voles and zokors. Co-dominating groups are ground squirrel, marmots, steppe lemmings, and red-backed voles. Small mammals from the Strashnaya cave indicate that during Late Pleistocene winters in the region could have been warmer than now. They also suggest highly mosaic biotopes around the cave in Late Pleistocene that includes open steppe, desert, floodplain, and forest. Small mammals show open areas such as steppes, floodplain and meadows in the early Holocene. The modern small mammal fauna confidently indicate taiga forest environments.

Small mammals from the early Pleistocene of the Granada Basin, southern Spain

The Pliocene and Pleistocene continental sedimentary records of the western sector of the Granada Basin, southern Spain, consist of alternating fluvial and lacustrine/palustrine sediments. Two Quaternary sections from this sector have been sampled: Huétor Tájar and Tojaire. They have yielded remains of rodents, insectivores and lagomorphs. The presence in the Huétor Tájar and Tojaire sections of Mimomys, Apodemus atavus, Castillomys rivas and two different species of Allophaiomys, indicates an Early Pleistocene age. These deposits, which are related to a fluvio-lacustrine system, can be differentiated from an older (Pliocene) braided fluvial system. Their dating has important repercussions on the paleogeographic reconstruction of the basin. The conditions inferred from the ecological preferences of the small mammal associations are wet and cold. These associations suggest a predominance of open herbaceous habitats, followed by forested habitats; semiaquatic habitats are the least represented.

Evolution of Borsodia (arvicolidae, mammalia) in the villanyian and in the early biharian

Borsodia Janossy and Meulen is a genus of rooted voles belonging to the Mimomys group. The genus was a common element of small mammal associations in the Late Pliocene and the beginning of the Early Pleistocene, that is in the Villanyian and the Early Biharian, a period of about 1.5 Ma. The species of Borsodia were widely distributed in a latitudinal steppic belt stretching from North China to Central Europe. One of most striking morphological trends in the dental evolution of Borsodia was progressing hypsodonty. The rate of hypsodonty increase in Borsodia was not constant. It increased in a way close to exponential, having a period of relatively low rise in the Early Villanyian and a period of accelerated rise in the Late Villanyian and the earliest Biharian. This is interpreted as a reflection of the growing aridization. Late species of Borsodia gave rise to several rootless lagurine species of the modern fauna in a smooth morphological transition.

Small‐Mammal Associations in Forested and Old‐field Habitats: A Quantitative Comparison

Population densities, physical condition, and several parameters (diversity, niche breadth, and ratio of dominance) of small—mammal communities were documented for two old—field and two forested sites from fall 1974 to spring 1977. White—footed mice (Peromyscus leucopus) were the most numerous species in forested habitats, and populations fluctuated asynchronously and were noncyclic. Physical condition indices were not significantly different between the two forested sites, but values were significantly higher for adults than juveniles and significantly different between different sample periods. Seasonal changes in physical condition were not correlated with population fluctuations. Meadow voles (Microtus pennsylvanicus) were the most numerous species in old—field habitats, and populations were cyclic and fluctuated synchronously with a 2—yr duration between peaks. Physical condition indices were not significantly different between different census periods, but were significantly higher for adults than juveniles. Seasonal changes in physical condition were not significantly correlated with population fluctuations. There was a negative correlation between average niche breadth and the number of species occurring in each census period for both Peromyscus— and Microtus—dominated communities, which suggested the occurrence of species packing. Niche breadth of species was positively correlated with their abundance of both forested and old—field habitats. Species diversity was negatively correlated with meadow vole density, suggesting that at high densities voles competitively excluded other species of small mammals. Species diversity of small—mammal communities in both habitats were extremely variable spatially and temporally. There were significant differences in diversity indices between sites within the same habitat but not between habitats.

Associations of Small Mammals on the Central High Plains of Eastern Colorado

Small mammal associations were sampled in six habitats on the central High Plains of eastern Colorado. The habitats consisted of grazed and ungrazed riparian woodland, sand sage- brush, and shortgrass. Ordination analysis revealed that grazing had the least effect on small mammal associations in shortgrass and the greatest effect on associations in riparian woodland. Moreover, grazed sand sagebrush supports a mammalian fauna more nearly like that of shortgrass than that of ungrazed sand sagebrush. These observations on the effects of grazing are interpreted in terms of understory vegetation. The mammalian fauna of the semi-arid central High Plains has been less extensively investigated than have those of mountainous regions to the west or the subhumid prairie to the east. Small mammal associations on the cen- tral High Plains have been characterized for only three types of habitat- riparian woodland in northeastern Colorado (Beidleman, 1954; Archibold, 1964); upland communities in southeastern Wyoming (Maxwell and Brown, 1968); and northern shortgrass prairie in northeastern Colorado (Grant and Birney, 1979). The purpose of this study was to characterize small mammal associations at six sites, three grazed and three ungrazed, in eastern Colo- rado. Unlike Grant and Birney (1979), who described community structure of small mammals in nine different regions of North American grassland, our objective was to relate small mammal associations to attributes of their local environments within one region of the Great Plains.