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535 results for “quaternary”
Data from: Plant controls on Late Quaternary whole ecosystem structure and function
Plants and animals influence biomass production and nutrient cycling in terrestrial ecosystems; however their relative importance remains unclear. We assessed the extent to which mega-herbivore species controlled plant community composition and nutrient cycling, relative to other factors during and after the Late Quaternary extinction event in Britain and Ireland, when two-thirds of the region's mega-herbivore species went extinct. Warmer temperatures, plant-soil and plant-plant interactions, and reduced burning contributed to the expansion of woody plants and declining nitrogen availability in our five study ecosystems. Shrub biomass in particular was consistently one of the strongest predictors of ecosystem change, equaling or exceeding the effects of other biotic and abiotic factors. In contrast, there was relatively little evidence for mega-herbivore control on plant community composition and nitrogen availability. The ability of plants to determine the fate of terrestrial ecosystems during periods of global environmental change may therefore be greater than previously thought.
Data from: Climatic forcing of Quaternary deep-sea benthic communities in the North Pacific Ocean
There is a growing evidence that changes in deep-sea benthic ecosystems are modulated by climate changes, but most evidence to date comes from the North Atlantic Ocean. Here we analyze new ostracod and published foraminiferal records for the last 250,000 years on Shatsky Rise in the North Pacific Ocean. Using linear models, we evaluate statistically the ability of environmental drivers (temperature, productivity, and seasonality of productivity) to predict changes in faunal diversity, abundance and composition. These microfossil data show glacial-interglacial shifts in overall abundances and species diversities that are low during glacial intervals and high during interglacials. These patterns replicate those previously documented in the North Atlantic Ocean, suggesting that the climatic forcing of the deep-sea ecosystem is widespread, and possibly global in nature. However, these results also reveal differences with prior studies that probably reflect the isolated nature of Shatsky Rise as a remote oceanic plateau. Ostracod assemblages on Shatsky Rise are highly endemic but of low diversity, consistent with the limited dispersal potential of these animals. Benthic foraminifera, by contrast, have much greater dispersal ability and their assemblages at Shatsky Rise show diversities typical for deep-sea faunas in other regions. Statistical analyses also reveal ostracod–foraminferal differences in relationships between environmental drivers and biotic change. Rarefied diversity is best explained as a hump-shaped function of surface productivity in ostracods, but as having a weak and positive relationship with temperature in foraminifera. Abundance shows a positive relationship with both productivity and seasonality of productivity in foraminifera, and a hump-shaped relationship in ostracods. Finally, species composition in ostracods is influenced by both temperature and productivity, but only a temperature effect is evident in foraminifera. Though complex in detail, the global-scale link between deep-sea ecosystems and Quaternary climate changes underscores the interaction between the physical and biological components of paleoceanographical research to better understand the history of the biosphere.
Data from: A phylogenetic analysis of the grape genus (Vitis L.) reveals broad reticulation and concurrent diversification during neogene and quaternary climate change
Background: Grapes are one of the most economically important fruit crops. There are about 60 species in the genus Vitis. The phylogenetic relationships among these species are of keen interest for the conservation and use of this germplasm. We selected 309 accessions from 48 Vitis species,varieties, and outgroups, examined ~11 kb (~3.4 Mb total) of aligned nuclear DNA sequences from 27 unlinked genes in a phylogenetic context, and estimated divergence times based on fossil calibrations. Results: Vitis formed a strongly supported clade. There was substantial support for species and less for the higher-level groupings (series). As estimated from extant taxa, the crown age of Vitis was 28 Ma and the divergence of subgenera (Vitis and Muscadinia) occurred at ~18 Ma. Higher clades in subgenus Vitis diverged 16 -- 5 Ma with overlapping confidence intervals, and ongoing divergence formed extant species at 12 -- 1.3 Ma. Several species had species-specific SNPs. NeighborNet analysis showed extensive reticulation at the core of subgenus Vitis representing the deeper nodes, with extensive reticulation radiating outward. Fitch Parsimony identified North America as the origin of the most recent common ancestor of extant Vitis species. Conclusions: Phylogenetic patterns suggested origination of the genus in North America, fragmentation of an ancestral range during the Miocene, formation of extant species in the late Miocene-Pleistocene, and differentiation of species in the context of Pliocene-Quaternary tectonic and climatic change. Nuclear SNPs effectively resolved relationships at and below the species level in grapes and rectified several misclassifications of accessions in the repositories. Our results challenge current higher-level classifications, reveal the abundance of genetic diversity in the genus that is potentially available for crop improvement, and provide a valuable resource for species delineation, germplasm conservation and use.
Data from: Quaternary climatic fluctuations and resulting climatically suitable areas for Eurasian owlets
Aim: The nested pattern in the geographical distribution of three Indian owlets, resulting in a gradient of endemicity, is hypothesized to be an impact of historical climate change. In current time, the Forest Owlet Athene blewitti is endemic to central India, and its range is encompassed within the ranges of the Jungle Owlet Glaucidium radiatum (distributed through South Asia) and Spotted Owlet Athene brama (distributed through Iran, South and Southeast Asia). Another phylogenetically close species, Little Owl Athene noctua, which is largely Palearctic in distribution, is hypothesized to have undergone severe range reduction during the Last Glacial Maximum, showing a post-glacial expansion. The present study tests hypotheses on the possible role of Quaternary climatic fluctuations in shaping geographical ranges of owlets. Methods: We used primary field observations, open access data, and climatic niche modeling to construct suitable climatic niches of four owlets for four periods, the Last Interglacial (~120-140 Ka), Last Glacial Maximum (~22 Ka), Mid-Holocene (~6 Ka) and Current (1960-1990). We performed climatic niche extent, breadth and overlap analyses, and tested if climatically suitable areas for owlets are nested in a relatively stable climate. Results: Climatically suitable areas for all owlets examined underwent cycles of expansion and reduction or a gradual expansion or reduction since the Last Interglacial. The Indian owlets show significant climatic niche overlap in the current period. Climatically suitable areas for Little Owl shifted southwards during the Last Glacial Maximum and expanded northwards in the post-glaciation period. For each owlet, the modeled climatic niches were nested in climatically stable areas. Main Conclusions: The study highlights the impact of Quaternary climate change in shaping the present distribution of owlets. This is relevant to the current scenario of climate change and global warming and can help inform conservation strategies, especially for the extremely range-restricted Forest Owlet.
Data from: Late Quaternary deep-sea ostracode taxonomy of the eastern North Atlantic Ocean
Taxonomic revision and re-evaluation of the eastern North Atlantic deep-sea ostracodes are conducted based on late Quaternary sediments from Ocean Drilling Program (ODP) Hole 982A, Rockall Plateau, eastern North Atlantic. Twenty one genera and 51 species were examined and (re-)illustrated with high-resolution scanning electron microscopy images. Six new species are described: Polycope lunaris, Argilloecia labri, Bythoceratina nuda, Cytheropteron colesoabyssorum, Cytheropteron colesopunctatum, and Cytheropteron paramediotumidum. Excellent fossil ostracode preservation in this sediment core enabled us to provide a robust taxonomic baseline of the eastern North Atlantic deep-sea ostracodes for application to palaeoceanographical, palaeoecological, and biogeographical studies.
Data from: Tropical rainforests that persisted: inferences from the Quaternary demographic history of eight tree species in the Guiana shield
How Quaternary climatic and geological disturbances influenced the composition of Neotropical forests is hotly debated. Rainfall and temperature changes during and/or immediately after the last glacial maximum (LGM) are thought to have strongly affected the geographical distribution and local abundance of tree species. The paucity of the fossil records in Neotropical forests prevents a direct reconstruction of such processes. To describe community-level historical trends in forest composition, we turned therefore to inferential methods based on the reconstruction of past demographic changes. In particular, we modelled the history of rainforests in the eastern Guiana Shield over a timescale of several thousand generations, through the application of approximate Bayesian computation and maximum-likelihood methods to diversity data at nuclear and chloroplast loci in eight species or subspecies of rainforest trees. Depending on the species and on the method applied, we detected population contraction, expansion or stability, with a general trend in favour of stability or expansion, with changes presumably having occurred during or after the LGM. These findings suggest that Guiana Shield rainforests have globally persisted, while expanding, through the Quaternary, but that different species have experienced different demographic events, with a trend towards the increase in frequency of light-demanding, disturbance-associated species.
Data from: Benthic communities under anthropogenic pressure show resilience across the Quaternary
The Southeast Pacific is characterized by rich upwelling systems that have sustained and been impacted by human groups for at least 12 ka. Recent fishing and aquaculture practices have put a strain on productive coastal ecosystems from Tongoy Bay, in north-central Chile. We use a temporal baseline to determine whether potential changes to community structure and composition over time are due to anthropogenic factors, natural climatic variations or both. We compiled a database (n = 33 194) with mollusc species abundances from the Mid-Pleistocene, Late Pleistocene, Holocene, dead shell assemblages and live-sampled communities. Species richness was not significantly different, neither were diversity and evenness indices nor rank abundance distributions. There is, however, an increase in relative abundance for the cultured scallop Argopecten, while the previously dominant clam Mulinia is locally very rare. Results suggest that impacts from both natural and anthropogenic stressors need to be better understood if benthic resources are to be preserved. These findings provide the first Pleistocene temporal baseline for the south Pacific that shows that this highly productive system has had the ability to recover from past alterations, suggesting that if monitoring and management practices continue to be implemented, moderately exploited communities from today have hopes for recovery.
Data from: The influence of Late Quaternary climate-change velocity on species endemism
The effects of climate change on biodiversity should depend in part on climate displacement rate (climate-change velocity) and its interaction with species' capacity to migrate. We estimated Late Quaternary glacial-interglacial climate-change velocity by integrating macroclimatic shifts since the Last Glacial Maximum with topoclimatic gradients. Globally, areas with high velocities were associated with marked absences of small-ranged amphibians, mammals and birds. The association between endemism and velocity was weakest in the highly vagile birds and strongest in the weakly dispersing amphibians, linking dispersal ability to extinction risk due to climate change. High velocity was also associated with low endemism at regional scales, especially in wet and aseasonal regions, where conditions otherwise favor high richness. Overall, we show that low-velocity areas are essential refuges for Earth's many small-ranged species.
FIGURE 1–2. 1 in A new genus and species of Enidae (Gastopoda: Pulmonata) from the Quaternary of the Balearic Islands (Western Mediterranean)
FIGURE 1–2. 1. Balearena gymnesica gen. nov., spec. nov. Holotype, upper coastal cliff at eastern edge of Es Carnatge, Palma de Mallorca, Mallorca island, Balearic Islands, Western Mediterranean. Shell length 16.7 mm; scale bar 2.0 mm. Not shown are a thin encrustation over most of the first whorl and minimal fractures on the peristome. 2. Protoconch sculpture of Balearena gymnesica. This reconstruction is based on partial remains of these delicate features that are observable in various specimens. Scale bar 0.5 mm.
FIGURE 4–5. 4 in A new genus and species of Enidae (Gastopoda: Pulmonata) from the Quaternary of the Balearic Islands (Western Mediterranean)
FIGURE 4–5. 4. Outlines of Mastus pupa (thick dark line, solid circles) and Balearena gymnesica (thin pale line, empty circles) in standard (front) orientation, scaled to same length and superimposed. The landmarks selected for the geometric morphometric analysis are indicated by circles, arrows showing the relative displacement among the two shapes. 5. Principal component analysis of truss distances defined by the landmarks shown in Fig. 4, measured on the specimens shown in Fig. 3. The first principal component (PCI) accounts for 54.95 % of total variance, and bears loadings mostly along the axis defined by shell length; the second principal component (PCII) explains 44.97 % of total variance, and its loadings are mostly along the axis perpendicular to shell length. Both components reflect changes with size, larger shells scoring higher on PCI and lower on PCII.
FIGURE 3 in A new genus and species of Enidae (Gastopoda: Pulmonata) from the Quaternary of the Balearic Islands (Western Mediterranean)
FIGURE 3. Comparison of shells of Mastus pupa (top row; Korbous, Tunisia) and Balearena gymnesica (bottom row; Es Carnatge, Mallorca). Scale bar 10 mm.
FIGURES 49–63 in The genus Haedropleura (Neogastropoda, Toxoglossa = Conoidea) in the Plio – Quaternary of the Mediterranean basin
FIGURES 49–63. SEM photographs of protoconch and of teleoconch details of live-collected and fossil shells. SEM photos are apical and lateral views (scale bars=0.1 mm). Details (right column) show ornamentation of last whorl of each specimen between suture and aperture, corresponding to the sinus. FIGURES 49–54. Haedropleura septangularis (Montagu) 49–50, # 4, Capo Comino (Nuoro), Holocene; 51, # 1, Punta Ala (Leghorn), Holocene; 52–53, # 11, 54, # 10, Melograni (Siena), Piacenzian (Pliocene). FIGURES 55–60. H. secalina (Philippi) 55–56, # 37, Ceuta (Spain), Holocene; 57, # 32, Procida (Naples), Holocene; 58–60, # 43, La Speranza (Siena), Piacenzian (Pliocene). FIGURES 61–63. H. bucciniformis (Bellardi) 61–62, # 26, La Serra (Siena), Piacenzian (Pliocene); 63, # 16, Melograni (Siena), Zanclean (Pliocene). #=shell number in Appendix 1.
FIGURES 1–6 in The genus Haedropleura (Neogastropoda, Toxoglossa = Conoidea) in the Plio – Quaternary of the Mediterranean basin
FIGURES 1–6. Haedropleura septangularis (Montagu). 1–3, # 12, Melograni (Siena), Piacenzian (Pliocene); 4–6, # 1, Punta Ala (Leghorn), live-collected specimen with operculum. FIGURES 7–12. H. secalina (Philippi). 7–9, # 43, La Speranza (Siena), Piacenzian (Pliocene); 10–12, # 32, Procida (Naples), live-collected specimen with operculum. FIGURES 13–18. H. bucciniformis (Bellardi) 13–15, # 16, Melograni (Siena), Piacenzian (Pliocene); 16–18, # 19, Terre Rosse (Siena), Zanclean/ Piacenzian (Pliocene). Scale bars 1 mm; #=shell number in Appendix 1.
FIGURES 37–42 in The genus Haedropleura (Neogastropoda, Toxoglossa = Conoidea) in the Plio – Quaternary of the Mediterranean basin
FIGURES 37–42. Haedropleura sp. 1 37–39, # 79, 40–42, # 77, Pieve Vecchia (Pisa), Piacenzian/Gelasian (Plio/Pleistocene). FIGURES 43–48. Haedropleura sp. 2 43–45, # 82, Stirone River (Parma) Gelasian (Pleistocene); 46–48, # 83, Codrignano (Bologna), Gelasian/Calabrian (Pleistocene). Scale bars 1 mm; #=shell number in Appendix 1.
FIGURES 19–27. Haedropleura formosa n in The genus Haedropleura (Neogastropoda, Toxoglossa = Conoidea) in the Plio – Quaternary of the Mediterranean basin
FIGURES 19–27. Haedropleura formosa n. sp. 19–21, # 54, Maiola (Bologna), Gelasian (Pleistocene); 22–24, # 46 holotype, 25–27, # 51 paratype, Codrignano (Bologna), Calabrian (Pleistocene). FIGURES 28–36. H. parva n. sp. 28–30, # 72, La Speranza (Siena), Piacenzian (Pliocene); 31–33, # 63 paratype, 34–36, # 62 holotype, Poggio alla Staffa (Siena), Zanclean (Pliocene). Scale bars 1 mm; #=shell number in Appendix 1.
FIGURES 64–75 in The genus Haedropleura (Neogastropoda, Toxoglossa = Conoidea) in the Plio – Quaternary of the Mediterranean basin
FIGURES 64–75. SEM photographs of protoconch and of teleoconch details of fossil shells. SEM photos are apical and lateral views (scale bars = 0.1 mm). Details (right column) show ornamentation of last whorl of each shell between suture and aperture, corresponding to the sinus. FIGURES 64–66. Haedropleura formosa n. sp. 64–65, # 50 paratype, 66, # 46 holotype, Codrignano (Bologna), Calabrian (Pleistocene). FIGURES 67–69. H. parva n. sp. 67–68, # 65 paratype, 69, # 62 holotype, Poggio alla Staffa (Siena), Zanclean (Pliocene). FIGURES 70–72. Haedropleura sp. 1 70–71, # 81, 72, # 79, Pieve Vecchia (Pisa), Piacenzian/Gelasian (Plio/Pleistocene). FIGURES 73–75. Haedropleura sp. 2 73–74, # 84, Castell'Anselmo (Leghorn), Zanclean/Gelasian (Plio/Pleistocene); 75, # 82, Stirone River (Parma), Gelasian (Pleistocene). #=shell number in Appendix 1.
FIGURE 10. Miracarus hurkai Kunst 1959 in Oribatid mite fossils from pre-Quaternary sediments in Slovenian caves II. Amiracarus pliocennatus n.gen., n.sp. (Microzetidae) from Pliocene, with comments on the other species of the genus
FIGURE 10. Miracarus hurkai Kunst 1959, holotype (Kunst Coll.). A—dorsal view, B—ventral view, C—lateral view, D—detail of pteromorph and bothridial area, E—detail of interlamellar region. Bars indicating 50 µm. Abbreviations: abn—anterior border of notogaster, bo—bothridium, cgl—circumgastric line, lam—lamella, pd1—pedotectum I, pt— pteromorph, sbl—subbothridial lamella, ss—sensillus, tu2—tutorial carina 2. Rest represents names of setae or setal insertions.
FIGURE 8. Amiracarus pliocennatus Miko, n. gen., n in Oribatid mite fossils from pre-Quaternary sediments in Slovenian caves II. Amiracarus pliocennatus n.gen., n.sp. (Microzetidae) from Pliocene, with comments on the other species of the genus
FIGURE 8. Amiracarus pliocennatus Miko, n. gen., n. sp., details of holotype and paratype (individuals under A and C from Plate 1). A—lamellar cuspis of holotype in detail, B—lamellar cuspis of paratype in detail, D—sensillus of holotype, E—sensillus of paratype, C—detail of rostrum, paratype, F—lateral view of prodorsum of holotype, G— lateral view of prodorsum, paratype. Abbreviations: bo—bothridium, ctu1—cuspis of tutorial carina 1, ctu3—cuspis of tutorial carina 3, cus—cuspis of lamella, inc—rostral incision, ku—carina ku on pedotectum I, lam—lamella, pd1— pedotectum I, pt—pteromorph, ss—sensillus, tu1—tutorial carina 1, tu2—tutorial carina 2, tu3—tutorial carina 3. Rest represents names of setae or setal insertions and lyrifissures.
FIGURE 9. Amiracarus pliocennatus Miko, n. gen., n in Oribatid mite fossils from pre-Quaternary sediments in Slovenian caves II. Amiracarus pliocennatus n.gen., n.sp. (Microzetidae) from Pliocene, with comments on the other species of the genus
FIGURE 9. Amiracarus pliocennatus Miko, n. gen., n. sp., details of holotype and paratype (individuals under A and C from Plate 1). A—gnathosoma of holotype, B—pteromorph of holotype, C—ventral view on podosoma of paratype, D— part of ventral view of holotype, E—posterior of podosoma of paratype, F—posterior of podosoma of holotype. Abbreviations: cgl—circumgastric line, cpl—circumpedal line, dis—discidium, go—genital opening, ku—carina ku on pedotectum I, mt—mentotectum, op—ovipositor, pd1—pedotectum I, pd2—pedotectum II, pt—pteromorph, R— acetabular protrusion of leg III, ru—rutellum, TrIII— trochanter III, TrIV—trochanter IV, tsI—trochanteral seta I, tsII— trochanteral seta II. Rest represents names of setae or setal insertions and lyrifissures.
FIGURE 7. Amiracarus pliocennatus Miko, n. gen., n in Oribatid mite fossils from pre-Quaternary sediments in Slovenian caves II. Amiracarus pliocennatus n.gen., n.sp. (Microzetidae) from Pliocene, with comments on the other species of the genus
FIGURE 7. Amiracarus pliocennatus Miko, n. gen., n. sp., holotype. A—dorsal view, B—ventral view, C—lateral view of prodorsum and podosoma, D—detail of lamella and lamellar cuspis. Bars indicating 50 µm (A, B, C). Abbreviations: abt—abaxial tooth of cuspis, adt—adaxial tooth of cuspis, ao—anal opening, bo—bothridium, cgl—circumgastric line, cpl—circumpedal line, cus—cuspis of lamellae, dis—discidium, go—genital opening, ku—carina ku on pedotectum I, lam—lamella, mt—mentotectum, abn—anterior border of notogaster, pd1—pedotectum I, pd2—pedotectum II, pt— pteromorph, R—acetabular protrusion of leg III, sl—notogastral lateromedial furrow, ss—sensillus, TrIII—trochanter III, TrIV—trochanter IV, tu1—tutorial carina 1, tu2—tutorial carina 2, tu3—tutorial carina 3. Rest represents names of setae or setal insertions and lyrifissures.
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Allen Brain Atlas
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