Who is adjusting to whom?: Differences in elephant diel activity in wildlife corridors across different human-modified landscapes

The global impact of increased human activities has consequences on the conservation of wildlife. Understanding how wildlife adapts to increased human pressures with urban expansion and agricultural areas is fundamental to future conservation plans of any species. However, there is a belief that large wild free-ranging carnivores and ungulates, cannot coexist with people, limited studies have looked at wildlife movements through differing human-dominated landscapes at finer spatial scales, in Africa. This information is vital as the human population is only going to increase and the wildlife protected areas decrease. We used remote-sensor camera traps to identify the movement patterns of African elephant (Loxodonta africana) through six wildlife corridors in Botswana. The wildlife corridors were located in two different human-dominated landscapes (agricultural/urban), with varying degrees of human impact. While we found that elephants use corridors in both landscapes, they use the urban corridors both diurnally and nocturnally in contrast to agricultural corridors which were only nocturnal. Our results provide evidence for temporal partitioning of corridor use by elephants. We identified that seasonality and landscape were important factors in determining the presence of elephants in the corridors. Our findings demonstrate that elephant diel patterns of use of the wildlife corridor differs based on the surrounding human land-uses on an hourly basis and daily basis, revealing potential adaptation and risk avoidance behaviour

A Novel Metagenomic Short-Chain Dehydrogenase/Reductase Attenuates Pseudomonas aeruginosa Biofilm Formation and Virulence on Caenorhabditis elegans

In Pseudomonas aeruginosa, the expression of a number of virulence factors, as well as biofilm formation, are controlled by quorum sensing (QS). N-Acylhomoserine lactones (AHLs) are an important class of signaling molecules involved in bacterial QS and in many pathogenic bacteria infection and host colonization are AHL-dependent. The AHL signaling molecules are subject to inactivation mainly by hydrolases (Enzyme Commission class number EC 3) (i.e. N-acyl-homoserine lactonases and N-acyl-homoserine-lactone acylases). Only little is known on quorum quenching mechanisms of oxidoreductases (EC 1). Here we report on the identification and structural characterization of the first NADP-dependent short-chain dehydrogenase/reductase (SDR) involved in inactivation of N-(3-oxo-dodecanoyl)-L-homoserine lactone (3-oxo-C12-HSL) and derived from a metagenome library. The corresponding gene was isolated from a soil metagenome and designated bpiB09. Heterologous expression and crystallographic studies established BpiB09 as an NADP-dependent reductase. Although AHLs are probably not the native substrate of this metagenome-derived enzyme, its expression in P. aeruginosa PAO1 resulted in significantly reduced pyocyanin production, decreased motility, poor biofilm formation and absent paralysis of Caenorhabditis elegans. Furthermore, a genome-wide transcriptome study suggested that the level of lasI and rhlI transcription together with 36 well known QS regulated genes was significantly (≥10-fold) affected in P. aeruginosa strains expressing the bpiB09 gene in pBBR1MCS-5. Thus AHL oxidoreductases could be considered as potent tools for the development of quorum quenching strategies

Behavioral responses of terrestrial mammals to COVID-19 lockdowns

Funding: This article is a contribution of the COVID-19 Bio-Logging Initiative, which is funded in part by the Gordon and Betty Moore Foundation (GBMF9881) and the National Geographic Society (NGS-82515R-20) (both grants to C.R.).COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals’ 1-hour 95th percentile displacements declined by 12% and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide.PostprintPeer reviewe