Climatic and Biotic Events of the Paleogene 2014, CBEP 2014

This special issue include the scientific contributes, short notes and abstracts, presented at the International Meeting: Climatic and Biotic Events of the Paleogene, CBEP 2014, held in Ferrara, Italy, July, 1-6, 2014, 10 thematic sessions. More than 140 participants from 20 countries attended the meeting, included the most famous experts. the http://web.fe.infn.it/cbep2014

Effects of management practices on water yield in small headwater catchments at Cordillera de los Andes in southern Chile

In several parts of the world, drinking water is obtained from springs in natural and managed mountainous forests. Since forests regulate quality as well as quantity of water, the effects of forest-management activities on water yield are an important subject of study. The objective of this study was to evaluate the effects of forest management on water yield in managed and unmanaged temperate native rainforests in the Andean range of southern Chile. The study area is located in San Pablo, a forest reserve of 2,184 ha located at the Andean range of southern Chile (39º 35’ S, 72º 07’ W, 600-925 m a.s.l.). From April 2003 to October 2008, seven experimental small catchments were monitored for rainfall, throughfall, stemflow, soil water infiltration, soil water percolation and runoff. In 2002, one catchment with a secondary deciduous forest was managed, through thinning, causing a reduction in basal area by 35% whereas the other one remained unthinned as control. Both watersheds are adjacent and are located at 600 – 720 m of elevation on deep loam textured volcanic soils (100 - 120 cm). In November 2006, a watershed covered with evergreen old-growth forests was thinned extracting 40% of the total basal area whereas another adjacent catchment remained unthinned as control. Both watersheds are located at 725 – 910 m a.s.l. and have the same aspects. The effects of management of deciduous secondary forests showed that for the period April 2003-March 2007, the mean value of the increase in total annual streamflow was 12.7%, ranging from 10.9% to 14.6%. Thinning of the evergreen old-growth forest increased the streamflow for the period November 2006-October 2008 with 6.1%, ranging from 4.4% to 7.8%, with greater differences during summertime (15.7 to 206%)

Population Biology Of A Coastal Dune-Dwelling Spider (Arctosa Sanctaerosae) Along The Hurricane Disturbed Northern Gulf Of Mexico Coast

With the continued increase in the number of tourists visiting the Northern Gulf coast in the last century and the resulting development of this coastline the habitat of Arctosa sanctaerosae has become fragmented; and the sprawl of large cities along the coast has further degraded available habitat. In addition to anthropogenic disturbance to this coastal region, hurricanes are an additional and natural perturbation to the ecosystem. This habitat has seen a number of major tropical storms over the last decade and I have sought to explore the impact of habitat destruction and storm-induced disturbance on a species of spider endemic to the coastal dunes of the Northern Gulf Coast. Arctosa sanctaerosae, family Lycosidae, is a wolf spider endemic to the secondary dunes of the white sandy beaches of the Northern Gulf of Mexico. The data presented here explore the status of populations of this species spanning the entire known range and the factors influencing population demography. These findings demonstrate the significant impact of storms on both disturbed and undisturbed habitat and reveal factors influencing the recovery of the spiders, relating this to ecological factors including the height of the dunes and density of vegetation before and following hurricanes Ivan and Katrina. These results reveal habitat characteristics that appear to play a large role in population persistence and components of human disturbance of habitat that have the greatest impact on populations of spiders. Using microsatellite markers I characterize the current structure of the subpopulations of Arctosa sanctaerosae, and current and historical patterns of interpopulation migration. Contemporary modeling methods compare current and historical levels of gene flow and document the decline in migration due to habitat fragmentation. Since the introduction of dense human development along the Northern Gulf of Mexico Coast, Arctosa sanctaerosae has seen what appears to have been a single, contiguous population subdivided and the isolates reduced in size. These results point to the need for further exploration of the status and continued monitoring of the species

Soil mite biodiversity: its relationship to grass species and influence on decomposition in the Konza tallgrass prairie

2005 Summer.Includes bibliographical references.Human activities are responsible for unprecedented extinction rates and global change. Species are disappearing faster than we can record their existence and before we determine their role in ecosystems. In no other system on Earth are we more uncertain about the true diversity of organisms and their roles than in soils. I have examined soil mite (Acari) species at the Konza Prairie Biological Station (KPBS), Kansas, USA, an uncultivated tallgrass prairie, to determine what mechanisms are responsible for their diversity, how alien invasive grasses may impact them, and what role their diversity plays in decomposition. The hypotheses that soil mite species richness, abundance and taxonomic diversity is greater beneath grasses in dicultures (different species) compared to monocultures (same species), beneath grasses of higher resource quality (lower C:N) compared to lower resource quality, and beneath heterogeneous mixes of grasses (C3 andC4 grasses growing together) compared to homogeneous mixes (C3 or C4 grasses) were tested using natural occurrences of grass species as treatments. Increased grass diversity supported a more species and phylogenetically rich soil mite fauna. This relationship was significant at depth but not in the upper soil horizon. Soil mite richness increased nonlinearly with grass species richness suggesting that simple extrapolations of soil faunal diversity based on plant species inventories may underestimate the richness of associated11lsoil mite communities. The proportion of mite size classes in dicultures was considerably different than those for monocultures. These data suggest that interspecific root competition results in increased mite habitat, abundance and diversity. There was no difference in soil mite richness between grass combinations of differing resource quality, or resource heterogeneity. Soil mites sampled beneath six native and one alien-invasive species of grass were similarly abundant, species rich, diverse, and taxonomically distinct. There was no evidence that the community composition of soil mites was specific to grass species or that a significant number of mite species had affinities for different grass species. The soil mite community was weakly related to soil environmental conditions. Only oribatid mites were related to, marginally, the species of grass present. The alien invasive grass species did not support a successionally younger mite fauna and had no influence on mite community structure, possibly because it had not substantially altered the soil environment. Rates of cotton strip decomposition (percent cotton strip tensile strength loss per day, CTSL), and soil mite abundance and species richness were measured at high and low fire frequency sites of the KPBS. Likelihood-based and information theoretic approaches were used to examine strength of evidence in data for models of CTSL representing the Null, Rivet and Redundant hypotheses of biodiversity and ecosystem function (BEF). The Null model including temperature, moisture and saturating effects in the total abundance of predatory mites (Mesostigmata) had more support in the data than any other models. Models representing Rivet and Redundant patterns of BEF settled on parameter values distinct from the Null models but had less support in the data regardless of which mite group was being considered. A significant trend was observed in the models' residuals from low fire frequency sites trends not observed in high fire frequency sites. I speculate that annually burned sites more closely emulate the agricultural system the models were originally designed for than low fire frequency sites, accounting for differences in model performance. Biophysical properties on low fire frequency sites such as increased litter cover, different soil carbon constituents or a different microbial community may regulate decomposition in a manner not accounted for by only soil temperature and moisture driving variables

The past and future human impact on mammalian diversity

To understand the current biodiversity crisis, it is crucial to determine how humans have affected biodiversity in the past. However, the extent of human involvement in species extinctions from the Late Pleistocene onward remains contentious. Here, we apply Bayesian models to the fossil record to estimate how mammalian extinction rates have changed over the past 126,000 years, inferring specific times of rate increases. We specifically test the hypothesis of human-caused extinctions by using posterior predictive methods. We find that human population size is able to predict past extinctions with 96% accuracy. Predictors based on past climate, in contrast, perform no better than expected by chance, suggesting that climate had a negligible impact on global mammal extinctions. Based on current trends, we predict for the near future a rate escalation of unprecedented magnitude. Our results provide a comprehensive assessment of the human impact on past and predicted future extinctions of mammals

Impacts of Revised Geologic Forcing Factors on the Phanerozoic Carbon Cycle

Traditionally, biogeochemical models are forced by the 87Sr/86Sr, δ13C and/or δ34S isotopic records. This study builds on existing work to present a forwards model for the entire Phanerozoic that aims instead to predict these isotopic variations, as well as the key environmental variables of global temperature, pCO2, pO2 and ocean sulphate concentration. The main geologic forcings; tectonic uplift, degassing, and basaltic area, of the COPSE biogeochemical model are revised following recent updates to the geologic record. In addition, a simple weatherability function is developed to account for the latitudinal location of large igneous province basalt. Further revisions are made to the model seafloor weathering and phosphorus weathering fluxes. A simplified strontium isotope system is adopted, which successfully reproduces the broad-scale Phanerozoic 87Sr/86Sr record, providing a test of the model predictions. The model also successfully predicts proxy data for both δ13Ccarb and δ34S. The updated model predictions of temperature and pCO2 are improved for the Early-Palaeozoic, which is characterised by a gradual cooling trend. However the duration of the Permo-Carboniferous glaciation is underestimated. This is attributed to an arbitrary reduction in the C:P burial ratio of plant biomass to account for the evolution of lignolytic organisms, although their impact has been questioned in recent research. Revision of the geologic forcings leads to an improved prediction of Phanerozoic pO2 that shows better agreement with other biogeochemical models in the Mesozoic, a period in which the original COPSE model probably overestimated the atmospheric oxygen concentration. Following the initial model updates, the complexity of the model is increased through the creation of a dynamic land area forcing, accounting for the incomplete preservation of large igneous provinces, and coupling the seafloor weathering function to both temperature and spreading rates. Whilst having clear impacts upon modelled temperature, pCO2 and pO2, such updates invalidate the 87Sr/86Sr prediction. This is addressed by increasing the complexity of the strontium isotope system through the inclusion of rubidium decay and a dynamic sediment strontium subsystem, however the 87Sr/86Sr prediction remains invalidated for large parts of the Phanerozoic. As such, a simplified strontium isotope system is seen to offer the best approximation of the Phanerozoic record

Impact of climate change on freshwater snail species' ranges

Global warming is expected to be associated with diverse changes in freshwater habitats in north-western Europe. Increasing evaporation, lower oxygen concentration due to increased water temperature and changes in precipitation pattern are likely to affect the survival ratio and reproduction rate of freshwater gastropods (Pulmonata, Basommatophora). This work is a comprehensive analyse of the climatic factors influencing their ranges both in the past and in the near future. A macroecological approach showed that for a great proportion of genera the ranges were projected to contract by 2080, even if unlimited dispersal was assumed. The forecasted warming in the cooler northern ranges predicted the emergence of new suitable areas, but also reduced drastically the available habitat in the southern part of the studied region. In order to better understand the ranges dynamics in the past and the post glacial colonisation patterns, an approach combining ecological niche modelling and phylogeography was used for two model species, Radix balthica and Ancylus fluviatilis. Phylogeographic model selection on a COI mtDNA dataset confirmed that R. balthica most likely spread from two central European disjunct refuges after the last glacial maximum. The phylogeographic analysis of A. fluviatilis, using 16S and COI mtDNA datasets, also inferred central European refugia. The absence of niche conservatism (adaptive potential) inferred for A. fluviatilis puts a cautionary note on the use of climate envelope models to predict the future ranges of this species. However, the other model species exhibited strong niche conservatism, which allow putting confidence into such predictions. A profound faunal shift will take place in Central Europe within the next century, either permitting the establishment of species currently living south of the studied region or the proliferation of organisms relying on the same food resources. This study points out the need for further investigations on the dispersal modes of freshwaters snails, since the future range size of the species depend on their ability to establish in newly available habitats. Likewise, the mixed mating system of these organisms gives them the possibility to fund a new population from a single individual. It will probably affect the colonisation success and needs further investigation