Environmental variables drive spatial patterns of trophic diversity in mammals

Understanding environmental drivers of species diversity has become increasingly important under climate change. Different trophic groups (predators, omnivores and herbivores) interact with their environments in fundamentally different ways and may therefore be influenced by different environmental drivers. Using random forest models, we identified drivers of terrestrial mammals' total and proportional species richness within trophic groups at a global scale. Precipitation seasonality was the most important predictor of richness for all trophic groups. Richness peaked at intermediate precipitation seasonality, indicating that moderate levels of environmental heterogeneity promote mammal richness. Gross primary production (GPP) was the most important correlate of the relative contribution of each trophic group to total species richness. The strong relationship with GPP demonstrates that basal-level resource availability influences how diversity is structured among trophic groups. Our findings suggest that environmental characteristics that influence resource temporal variability and abundance are important predictors of terrestrial mammal richness at a global scale.

Frugivory and Seed Dispersal by Carnivorans

Seed dispersal is critical to the ecological performance of sexually reproducing plant species and the communities that they form. The Mammalian order Carnivora provide valuable and effective seed dispersal services but tend to be overlooked in much of the seed dispersal literature. Here we review the literature on the role of Carnivorans in seed dispersal, with a literature search in the Scopus reference database. Overall, we found that Carnivorans are prolific seed dispersers. Carnivorans’ diverse and plastic diets allow them to consume large volumes of over a hundred families of fruit and disperse large quantities of seeds across landscapes. Gut passage by these taxa generally has a neutral effect on seed viability. While the overall effect of Carnivorans on seed dispersal quality is complex, Carnivorans likely increase long-distance dispersal services that may aid the ability of some plant species to persist in the face of climate change.

Space Use and Movement of Urban Bobcats

Simple Summary

The bobcat (Lynx rufus) is a medium-sized carnivore that lives in remote and urban habitats. Here, we evaluate how bobcats exploit a highly urbanized section of the Dallas–Fort Worth metroplex, Texas, USA by evaluating their space use and activity patterns. We found that bobcats use more natural habitat areas within urban areas, such as agricultural fields and creeks, and avoid highly anthropogenic features, such as roads. Bobcat home ranges overlap one another, especially in areas with preferred habitat types, but they are neither avoiding nor attracted to one another during their daily movements. This study highlights how bobcats are able to navigate a built environment and the importance of green space in such places.

Abstract

Global urbanization is rapidly changing the landscape for wildlife species that must learn to persist in declining wild spacing, adapt, or risk extinction. Many mesopredators have successfully exploited urban niches, and research on these species in an urban setting offers insights into the traits that facilitate their success. In this study, we examined space use and activity patterns from GPS-collared bobcats (Lynx rufus) in the Dallas–Fort Worth metroplex, Texas, USA. We found that bobcats select for natural/agricultural features, creeks, and water ways and there is greater home-range overlap in these habitats. They avoid roads and are less likely to have home-range overlap in habitats with more roads. Home-range size is relatively small and overlap relatively high, with older animals showing both greater home-range size and overlap. Simultaneous locations suggest bobcats are neither avoiding nor attracted to one another, despite the high overlap across home ranges. Finally, bobcats are active at all times of day and night. These results suggest that access to natural features and behavioral plasticity may enable bobcats to live in highly developed landscapes.

Genetic health and population monitoring of two small black bear (Ursus americanus) populations in Alabama, with a regional perspective of genetic diversity and exchange

One of the major concerns in conservation today is the loss of genetic diversity which is a frequent consequence of population isolation and small population sizes. Fragmentation of populations and persecution of carnivores has posed a substantial threat to the persistence of free ranging carnivores in North America since the arrival of European settlers. Black bears have seen significant reductions in range size from their historic extent, which is most pronounced in the southeastern United States and even more starkly in Alabama where until recently bears were reduced to a single geographically isolated population in the Mobile River Basin. Recently a second population has naturally re-established itself in northeastern Alabama. We sought to determine size, genetic diversity and genetic connectivity for these two populations in relation to other regional populations. Both populations of black bears in Alabama had small population sizes and had moderate to low genetic diversity, but showed different levels of connectivity to surrounding populations of bears. The Mobile River Basin population had a small population size at only 86 individuals (76–124, 95% C.I.), the lowest genetic diversity of compared populations (richness = 2.33, Ho and He = 0.33), and showed near complete genetic isolation from surrounding populations across multiple tests. The newly recolonizing population in northeastern Alabama had a small but growing population doubling in 3 years (34 individuals 26–43, 95% C.I.), relatively moderate genetic diversity compared to surrounding populations (richness = 3.32, Ho = 0.53, He = 0.65), and showed a high level of genetic connectivity with surrounding populations.

Interaction of nucleotides with acidic fibroblast growth factor (FGF-1)

A wide variety of nucleotides are shown to bind to acidic fibroblast growth factor (aFGF) as demonstrated by their ability to (1) inhibit the heat-induced aggregation of the protein, (2) enhance the thermal stability of aFGF as monitored by both intrinsic fluorescence and CD, (3) interact with fluorescent nucleotides and displace a bound polysulfated naphthylurea compound, suramin, (4) reduce the size of heparin-aFGF complexes, and (5) protect a reactive aFGF thiol group. The binding of mononucleotides, diadenosine compounds (ApnA), and inorganic polyphosphates to aFGF is enhanced as the degree of phosphorylation of these anions is increased with the presence of the base reducing the apparent binding affinity. The nature of the base appears to have much less effect. Photoactivatable nucleotides (8N3-ATP, 2N3-ATP, 8N3-GTP, and 8N3-Ap4A) were employed to covalently label the aFGF nucleotide binding site. In general, Kd's in the low micromolar range are observed. Protection against 90% displacement is observed at several hundred micromolar nucleotide concentration. Using 8N3-ATP as a prototypic reagent, photolabeled aFGF was proteolyzed with trypsin and chymotrypsin and labeled peptides were isolated and sequenced resulting in the identification of 10 possible labeled amino acids (Y8, G20, H21, T61, K112, K113, S116, R119, R122, H124). On the basis of the crystal structure of bovine aFGF, eight of the prospective labeled sites appear to be dispersed around the perimeter of the growth factor's presumptive polyanion binding site. On residue (T61) is more distally located but still proximate to several positively charged residues, and another (Y8) is not locatable in crystal structures. Using heparin affinity chromatography, at least three distinct photolabeled aFGF species were resolved. These labeled complexes display diminished affinity for heparin and a reduced ability to stimulate mitogenesis even in the presence of polyanions such as heparin. In conclusion, nucleotides bind apparently nonspecifically to the polyanion binding site of aFGF but nevertheless are capable of modulating the protein's activity. Evidence for the presence of a second or more extended polyanion binding site and the potential biological significance of these results in terms of potential natural ligands of aFGF are also discussed but not resolved.