Horizon annealing: a collection‐based approach to automated sequencing of the fossil record

Sheets, H.D., Mitchell, C.E., Izard, Z.T., Willis, J.M., Melchin, M.J. & Holmden, C. 2012: Horizon annealing: a collection‐based approach to automated sequencing of the fossil record. Lethaia, Vol. 45, pp. 532–547. A number of different approaches to quantitative biochronology have been proposed and used to construct high‐resolution time‐scales for a range of uses. We present a new approach, horizon annealing, which uses simulated annealing to optimize the sequencing of collection horizons. Temporal sequences of events produced by this method are compared with those produced by graphic correlation, CONOP and RASC for a series of previously studied exemplar data sets. Horizon annealing produces results similar to other methods, but it does have properties (the ordination of collections and the avoidance of some local minima) that make it useful for high‐resolution studies, particularly those based on capture‐mark‐recapture methods requiring detailed presence–absence data for individual collections and taxa. □ Chronostratigraphy, graphic correlation, graptolite, rate of evolution, CONOP9.     

Algal biochar: effects and applications

Algae represent a promising target for the generation of bioenergy through slow pyrolysis, leading to the production of biochar. This study reports experiments conducted on the production of freshwater and saltwater macroalgal biochar in pilot‐scale quantities, the physical and chemical characteristics of the biochars, and their impact on plant growth. The biochars are low in carbon (C) content, surface area and cation exchange capacity, while being high in ash and nutrients. Trace element analysis demonstrates that macroalgal biochar produced from unpolluted water does not contain toxic trace elements in excess of levels mandated for unrestricted use as a biosolids amendment to soils. Pot trials conducted using a C and nutrient‐poor soil, without and with additional fertilizer, demonstrate dramatic increases between 15 and 32 times, respectively, in plant growth rate for biochar treatments compared with the no biochar controls, with additional smaller increases when fertilizer was added. Pot trials conducted using a relatively fertile agricultural soil showed smaller but significant impacts of biochar amendment over the controls.     

Demographic Sensitivity of Population Change in Northern Bobwhite

Abstract: The northern bobwhite (Colinus virginianus) is an economically important gamebird that is currently undergoing widespread population declines. Despite considerable research on the population ecology of bobwhites, there have been few attempts to model population dynamics of bobwhites to determine the contributions of different demographic parameters to variance of the finite rate of population change (Λ). We conducted a literature review and compiled 405 estimates of 9 demographic parameters from 49 field studies of bobwhites. To identify demographic parameters that might be important for management, we used life-stage simulation analyses (LSA) to examine sensitivity of Λ to simulated variation in 9 demographic parameters for female bobwhites. In a baseline LSA based on uniform distributions bounded by the range of estimates for each demographic parameter, bobwhite populations were predicted to decline (Λ = 0.56) and winter survival of adults made the greatest contribution to variance of Λ (r² = 0.453), followed by summer survival of adults (r² = 0.163), and survival of chicks (r² = 0.120). Population change was not sensitive to total clutch laid, nest survival, egg hatchability, or 3 parameters associated with the number of nesting attempts (r²<0.06). Our conclusions were robust to alternative simulation scenarios, and parameter rankings changed only if we adjusted the lower bounds of winter survival upwards. Bobwhite populations were not viable with survival rates reported from most field studies. Survival rates may be depressed below sustainable levels by environmental conditions or possibly by impacts of capture and telemetry methods. Overall, our simulation results indicate that management practices that improve seasonal survival rates will have the greatest potential benefit for recovery of declining populations of bobwhites.     

Associating Seasonal Range Characteristics With Survival of Female White-Tailed Deer

ABSTRACT Delineating populations is critical for understanding population dynamics and managing habitats. Our objective was to delineate subpopulations of migratory female white-tailed deer (Odocoileus virginianus) in the central Black Hills, South Dakota and Wyoming, USA, on summer and winter ranges. We used fuzzy classification to assign radiocollared deer to subpopulations based on spatial location, characterized subpopulations by trapping sites, and explored relationships among survival of subpopulations and habitat variables. In winter, Kaplan-Meier estimates for subpopulations indicated 2 groups: high (S = 0.991 ± 0.005 [x̄ ± SE]) and low (S = 0.968 ± 0.007) weekly survivorship. Survivorship increased with basal area per hectare of trees, average diameter at breast height of trees, percent cover of slash, and total point-center quarter distance of trees. Cover of grass and forbs were less for the high survivorship than the lower survivorship group. In summer, deer were spaced apart with mixed associations among subpopulations. Habitat manipulations that promote or maintain large trees (i.e., basal area = 14.8 m²/ha and average dbh of trees = 8.3 cm) would seem to improve adult survival of deer in winter.     

Markedly discordant mitochondrial DNA and allozyme phylogenies of tube-nosed fruit bats, Nyctimene, at the Australian–Oriental biogeographical interface

Australo-Papuan tube-nosed fruit bats of the genus Nyctimene reach their most westerly distribution on the island archipelagos of eastern Indonesia. A recent morphological examination indicates three species occur on Moluccan islands. Both allozyme electrophoresis and mitochondrial DNA (mtDNA) sequencing reveal there are only two species present, Nyctimene cephalotes and Nyctimene albiventer , but there is considerable disparity between the results obtained from the two genetic data sets. Allozyme data indicate N. albiventer occurs on Wokam, which sits on the Australian continental shelf and was joined to Australo-Papua during the last glacial maximum, and N. cephalotes on the other Moluccan islands, all of which are off the continental shelf. Divergence of these two species is dated at approximately 1.5 Mya. By contrast, the mtDNA gene tree shows two deep clades, one containing all specimens from Wokam and Yamdena, and the second all the specimens from the other islands. This especially marked incongruence between the two genetic data sets is ascribed to either a single introgression event of N. albiventer mtDNA into N. cephalotes on Yamdena at around 100 000 ya or lineage sorting of very old mtDNA lineages that coalesce a rather long time before the speciation event. These results highlight that caution should be exercised when relying on mtDNA as barcodes in species taxonomy. The continental-associated N. albiventer on Wokam has higher levels of allozyme heterozygosity and mtDNA nucleotide diversity than the N. cephalotes populations occurring on the more remote islands, indicating that this colonizing species has experienced bottlenecks and/or a low effective population size since speciation.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 589–602.     

The effects of locomotion on the structural characteristics of avian limb bones

Despite the wide range of locomotor adaptations in birds, little detailed attention has been given to the relationships between the quantitative structural characteristics of avian limb bones and bird behaviour. Possible differences in forelimb relative to hindlimb strength across species have been especially neglected. We generated cross‐sectional, geometric data from peripheral quantitative computed tomography scans of the humerus and femur of 127 avian skeletons, representing 15 species of extant birds in 13 families. The sample includes terrestrial runners, arboreal perchers, hindlimb‐propelled divers, forelimb‐propelled divers and dynamic soarers. The hindlimb‐propelled diving class includes a recently flightless island form. Our results demonstrate that locomotor dynamics can be differentiated in most cases based on cross‐sectional properties, and that structural proportions are often more informative than bone length proportions for determining behaviour and locomotion. Recently flightless forms, for example, are more easily distinguished using structural ratios than using length ratios. A proper phylogenetic context is important for correctly interpreting structural characteristics, especially for recently flightless forms. Some of the most extreme adaptations to mechanical loading are seen in aquatic forms. Penguins have forelimbs adapted to very high loads. Aquatic species differ from non‐aquatic species on the basis of relative cortical thickness. The combination of bone structural strength and relative cortical area of the humerus successfully differentiates all of our locomotor groups. The methods used in this study are highly applicable to fossil taxa, for which morphology is known but behaviour is not. The use of bone structural characteristics is particularly useful in palaeontology not only because it generates strong signals for many locomotor guilds, but also because analysing such traits does not require knowledge of body mass, which can be difficult to estimate reliably for fossil taxa. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153 , 601–624.     

Global assessment of coral bleaching and required rates of adaptation under climate change

Elevated ocean temperatures can cause coral bleaching, the loss of colour from reef‐building corals because of a breakdown of the symbiosis with the dinoflagellate Symbiodinium. Recent studies have warned that global climate change could increase the frequency of coral bleaching and threaten the long‐term viability of coral reefs. These assertions are based on projecting the coarse output from atmosphere–ocean general circulation models (GCMs) to the local conditions around representative coral reefs. Here, we conduct the first comprehensive global assessment of coral bleaching under climate change by adapting the NOAA Coral Reef Watch bleaching prediction method to the output of a low‐ and high‐climate sensitivity GCM. First, we develop and test algorithms for predicting mass coral bleaching with GCM‐resolution sea surface temperatures for thousands of coral reefs, using a global coral reef map and 1985–2002 bleaching prediction data. We then use the algorithms to determine the frequency of coral bleaching and required thermal adaptation by corals and their endosymbionts under two different emissions scenarios. The results indicate that bleaching could become an annual or biannual event for the vast majority of the world's coral reefs in the next 30–50 years without an increase in thermal tolerance of 0.2–1.0°C per decade. The geographic variability in required thermal adaptation found in each model and emissions scenario suggests that coral reefs in some regions, like Micronesia and western Polynesia, may be particularly vulnerable to climate change. Advances in modelling and monitoring will refine the forecast for individual reefs, but this assessment concludes that the global prognosis is unlikely to change without an accelerated effort to stabilize atmospheric greenhouse gas concentrations.     

Two new late Carboniferous Neuropteris species (Medullosales) from Saarland, Germany and their palaeobiogeographical significance

Two new species ( Neuropteris terminiscus and N. kneuperi ) are described from the Bolsovian ('Westphalian C') of Saarland. N. terminiscus had previously been misidentified as Paripteris pseudograndinioides , but the pinnae are clearly imparipinnate and thus cannot belong to that morphogenus. N. kneuperi had previously been misidentified as Neuropteris obliqua and N. heterophylla , both which appear to be absent from Saar-Lorraine. This is considered further evidence of the distinctive nature of the Westphalian vegetation of the Saar-Lorraine Basin, especially among the seed-plants.  © 2002 The Linnean Society of London , Botanical Journal of the Linnean Society , 2002, 139 , 193–205.