Coherence of terrestrial vertebrate species richness with external drivers across scales and taxonomic groups

Aim

Understanding connections between environment and biodiversity is crucial for conservation, identifying causes of ecosystem stress, and predicting population responses to changing environments. Explaining biodiversity requires an understanding of how species richness and environment covary across scales. Here, we identify scales and locations at which biodiversity is generated and correlates with environment.

Location

Full latitudinal range per continent.

Time Period

Present day.

Major Taxa Studied

Terrestrial vertebrates: all mammals, carnivorans, bats, songbirds, hummingbirds, amphibians.

Methods

We describe the use of wavelet power spectra, cross-power and coherence for identifying scale-dependent trends across Earth's surface. Spectra reveal scale- and location-dependent coherence between species richness and topography (E), mean annual precipitation (Pn), temperature (Tm) and annual temperature range (ΔT).

Results

>97% of species richness of taxa studied is generated at large scales, that is, wavelengths $\gtrsim {10}^3$ km, with 30%–69% generated at scales $\gtrsim {10}^4$ km. At these scales, richness tends to be highly coherent and anti-correlated with E and ΔT, and positively correlated with Pn and Tm. Coherence between carnivoran richness and ΔT is low across scales, implying insensitivity to seasonal temperature variations. Conversely, amphibian richness is strongly anti-correlated with ΔT at large scales. At scales $\lesssim {10}^3$ km, examined taxa, except carnivorans, show highest richness within the tropics. Terrestrial plateaux exhibit high coherence between carnivorans and E at scales $\sim {10}^3$ km, consistent with contribution of large-scale tectonic processes to biodiversity. Results are similar across different continents and for global latitudinal averages. Spectral admittance permits derivation of rules-of-thumb relating long-wavelength environmental and species richness trends.

Main Conclusions

Sensitivities of mammal, bird and amphibian populations to environment are highly scale dependent. At large scales, carnivoran richness is largely independent of temperature and precipitation, whereas amphibian richness correlates strongly with precipitation and temperature, and anti-correlates with temperature range. These results pave the way for spectral-based calibration of models that predict biodiversity response to climate change scenarios.     

Fringe patterns and measurement on dorsal moiré topography in Japanese children, aged 13 and 14

Dorsal moiré topographies of 165 boys and 156 girls, aged 13 and 14, were investigated. Moiré fringe patterns were classified into seven types, of which type IV, thin and symmetric back, was most frequent (29% in boys and 22% in girls), and types I and II thoracic, fleshy back, were observed in 15% of boys and 29% of girls. Settling four prominent points on the back, length, depth (number of fringes), angles between these points, and the most depressed point on the lumbar region were measured. Neither bilateral or sex differences were detected in length and depth measurements, whereas larger right side angles were observed as a general tendency. In both sexes, significant correlation was detected between measurements on points situated in the inner part of the back, while on points situated in the outer parts only angle and length correlation was significant.     

Analysis of Large-Scale Spatial Heterogeneity in Vegetation Indices among North American Landscapes

We analyzed the spatial heterogeneity in vegetation indices among 13 North American landscapes by using full Landsat Thematic Mapper images. Landscapes varied broadly in the statistical distribution of vegetation indices, but were successfully ordinated by using a measure of central tendency (the mean) and a measure of dispersion (the standard deviation or the coefficient of variation). Differences in heterogeneity among landscapes were explained by their topographic relief and their land cover. Landscape heterogeneity (standard deviation of the Normalized Difference Vegetation Index, NDVI) tended to increase linearly with topographic relief (standard deviation of elevation), but landscapes with low relief were much more heterogeneous than expected from this relationship. The latter were characterized by a large proportion of agricultural land. Percent agriculture, in turn, was inversely related to topographic relief. The strength of these relationships was evaluated against changes in image spatial resolution (grain size). Aggregation of NDVI images to coarser grain size resulted in steady decline of their standard deviation. Although the relationship between landscape heterogeneity and explanatory variables was generally preserved, rates of decrease in heterogeneity with grain size differed among landscapes. A spatial autocorrelation analysis showed that rates of decrease were related to the scale at which pattern is manifested. On one end of the spectrum are agricultural, low-relief landscapes with low spatial autocorrelation and small-scale heterogeneity associated with fields; their heterogeneity decreased sharply as grain size increased. At the other end, desert landscapes were characterized by low small-scale heterogeneity, high spatial autocorrelation, and almost no change in heterogeneity as grain sized was increased—their heterogeneity, associated with land forms, was present at a large scale. Received 1 October 1997; accepted 11 February 1998.     

Topography of mutational signatures in human cancer

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Influence of nanophase titania topography on bacterial attachment and metabolism

Surfaces with nanophase compared to conventional (or nanometer smooth) topographies are known to have different properties of area, charge, and reactivity. Previously published research indicates that the attachment of certain bacteria (such as Pseudomonas fluorescens 5RL) is higher on surfaces with nanophase compared to conventional topographies, however, their effect on bacterial metabolism is unclear. Results presented here show that the adhesion of Pseudomonas fluorescens 5RL and Pseudomonas putida TVA8 was higher on nanophase than conventional titania. Importantly, in terms of metabolism, bacteria attached to the nanophase surfaces had higher bioluminescence rates than on the conventional surfaces under all nutrient conditions. Thus, the results from this study show greater select bacterial metabolism on nanometer than conventional topographies, critical results with strong consequences for the design of improved biosensors for bacteria detection.     

Variation in density of cattle-visiting muscid flies between Danish inland pastures

Abstract. The density of cattle-visiting flies (Muscidae) and the load of black-flies (Simulium spp.) were estimated in twelve and eighteen inland pastures in Denmark in 1984 and 1985 respectively. No differences in the geographical distribution pattern of the predominant cattle-visiting Muscidae were recorded, whilst the relative abundance and density of the species and the total fly-load varied considerably between pastures. In most cases the mean loads of Haema-tobia irritans (L.) and Hydrotaea irritans (Fall.) on heifers varied significantly in relation to site topography and shelter. These crude site variables explained 65–98% of the variation in densities of horn flies and sheep head flies observed between pastures. Highest densities of Hydrotaea irritans were primarily associated with permanent, low-lying, fairly sheltered grassland sites, whereas the density was low in temporary, dry, wind-exposed pastures. A comparable relationship was found for Haematobia irritans. With Haematobosca stimulans (Mg.) and Morellia spp. no relation between grassland environment and fly density was detected.