Ecology, more than antibiotics consumption, is the major predictor for the global distribution of aminoglycoside-modifying enzymes

Antibiotics consumption and its abuses have been historically and repeatedly pointed out as the major driver of antibiotic resistance emergence and propagation. However, several examples show that resistance may persist despite substantial reductions in antibiotic use, and that other factors are at stake. Here we study the temporal, spatial, and ecological distribution patterns of aminoglycoside resistance, by screening more than 160,000 publicly available genomes for 27 clusters of genes encoding aminoglycoside-modifying enzymes (AMEGs). We find that AMEGs are ubiquitous: about 25% of sequenced bacteria carry AMEGs. These bacteria were sequenced from all the continents and terrestrial biomes, and belong to a wide number of phyla. By focusing on several European countries between 1997 and 2018, we show that aminoglycoside consumption has little impact on the prevalence of AMEG-carrying bacteria, whereas most variation in prevalence is observed among biomes. We further analyze the resemblance of resistome compositions across biomes: soil, wildlife, and human samples appear to be central to understand the exchanges of AMEGs between different ecological contexts. Moreover, the genomic distribution of AMEGs suggests a selection for widening resistance spectra, mostly driven by mobile genetic elements. Together, these results support the idea that interventional strategies based on reducing antibiotic use should be complemented by a stronger control of exchanges, especially between ecosystems.

DarkCideS 1.0, a global database for bats in karsts and caves

Understanding biodiversity patterns as well as drivers of population declines, and range losses provides crucial baselines for monitoring and conservation. However, the information needed to evaluate such trends remains unstandardised and sparsely available for many taxonomic groups and habitats, including the cave-dwelling bats and cave ecosystems. Here, we present the DarkCideS 1.0, a global database of bat caves and bat species based on curated data from the literature, personal collections, and existing datasets. The database contains information for geographical distribution, ecological status, species traits, and parasites and hyperparasites for 679 bat species known to occur in caves or use caves in their life-histories. The database contains 6746 georeferenced occurrences for 402 cave-dwelling bat species from 2002 cave sites in 46 countries and 12 terrestrial biomes. The database has been developed to be a collaborative, open-access, and user-friendly platform, allowing continuous data-sharing among the community of bat researchers and conservation biologists. The database has a range of potential applications in bat research and enables comparative monitoring and prioritisation for conservation.

Predicting Global Terrestrial Biomes with Convolutional Neural Network

A biome is a major regional ecological community characterized by distinctive life forms and principal plants. Many empirical schemes such as the Holdridge Life Zone (HLZ) system have been proposed and implemented to predict the global distribution of terrestrial biomes. Knowledge of physiological climatic limits has been employed to predict biomes, resulting in more precise simulation, however, this requires different sets of physiological limits for different vegetation classification schemes. Here, we demonstrate an accurate and practical method to construct empirical models for biome mapping: A convolutional neural network (CNN) was trained by an observation-based biome map, as well as images depicting air temperature and precipitation. The trained model accurately simulated a global map of current terrestrial biome distribution. Then, the trained model was applied to climate scenarios toward the end of the 21st century, predicting a significant shift in global biome distribution with rapid warming trends. Our results demonstrate that the proposed CNN approach can provide an efficient and objective method to generate preliminary estimations of the impact of climate change on biome distribution. Moreover, we anticipate that our approach could provide a basis for more general implementations to build empirical models of other climate-driven categorical phenomena.

Conservation of Earth’s biodiversity is embedded in Indigenous fire stewardship

Increasingly, severe wildfires have led to declines in biodiversity across all of Earth’s vegetated biomes [D. B. McWethy et al., Nat. Sustain. 2, 797–804 (2019)]. Unfortunately, the displacement of Indigenous peoples and place-based societies that rely on and routinely practice fire stewardship has resulted in significant declines in biodiversity and the functional roles of people in shaping pyrodiverse systems [R. Bliege Bird et al., Proc. Natl. Acad. Sci. U.S.A. 117, 12904–12914 (2020)]. With the aim of assessing the impacts of Indigenous fire stewardship on biodiversity and species function across Earth’s major terrestrial biomes, we conducted a review of relevant primary data papers published from 1900 to present. We examined how the frequency, seasonality, and severity of human-ignited fires can improve or reduce reported metrics of biodiversity and habitat heterogeneity as well as changes to species composition across a range of taxa and spatial and temporal scales. A total of 79% of applicable studies reported increases in biodiversity as a result of fire stewardship, and 63% concluded that habitat heterogeneity was increased by the use of fire. All studies reported that fire stewardship occurred outside of the window of uncontrollable fire activity, and plants (woody and nonwoody vegetation) were the most intensively studied life forms. Three studies reported declines in biodiversity associated with increases in the use of high-severity fire as a result of the disruption of Indigenous-controlled fire regimes with the onset of colonization. Supporting Indigenous-led fire stewardship can assist with reviving important cultural practices while protecting human communities from increasingly severe wildfires, enhancing biodiversity, and increasing ecosystem heterogeneity.

FIRE CHARACTERISTICS OF ZAGROS FOREST ECOSYSTEM, KERMANSHAH PROVINCE, WESTERN IRAN

Fires are an integral part of many terrestrial biomes and a major source of disturbance in nature. The purpose of this study is to assess the causes and characteristics of fires in the Zagros ecosystem in ten consecutive years from 2011 to 2020. To conduct this research, wholly fire events that occurred in natural areas in the Gilan-e Gharb basin during the fire season detailed in a decade. In practice, immediately after informed of the occurrence of fires in natural areas, research data recorded. Totally, 233 event fires have occurred in the ten years from 2011 to 2020. The fire affected approximately 11,420 hectares of natural areas. The highest frequency of monthly fires during the months of the fire season includes 53, 44, and 40 events, which concern August, July, and September, respectively. The frequency of fires in different components of natural resources shows that the highest and the least frequency includes non-wooded pastures (44.6±5.6) and mixed Forest-rangeland (14.25±4.11). The most causes of fire in natural areas include recreation and hunting (43.3±16.1). The maximum frequency of the fire area includes <100 hectares’ classes (83.6±20.57). Most fires suppressed in a very short period (64.27±26.17). Daneh Khoshk, Nawdar, Poshteh, Peikoleh, Belaleh, Cheleh – Ghalajeh as well as Chikan regions include a high risk of fire. The issues connected to the fire are multidimensional. It deals with climatic and habitat factors, social issues, and the nature conservation culture institutionalization among the local people. To reduce the fire and the resulting damage, it is necessary to perform basic proceedings in whole fields.

Terrestrial biomes: a conceptual review

Aims: We attempt to review the conceptualisation, science and classification of biomes and propose to limit the definition of a biome to potential natural vegetation as determined by general environmental variables. Results: Classifying the distribution and abundance of vegetation types on earth has been a central tenet of vegetation science since Humboldt’s classic studies in the early 1800s. While the importance of such classifications only grows in the wake of extreme changes, this review demonstrates that there are many fundamentally different approaches to define biomes, hitherto with limited efforts for unifying concepts among disciplines. Consequently, there is little congruence between the resulting maps, and widely used biome maps fail to delimit areas with consistent climate profiles. Conclusions: Gaps of knowledge are directly related to research avenues, and suggestions for defining and classifying biomes, as well as modelling their distributions, are provided. These suggestions highlight the primary importance of the climate, argue against using anthropogenic drivers to define biomes and stabilize the concept of biome to escape from the current polysemy. The last two decades have seen an emergence of new approaches, e.g., using satellite imagery to determine growth patterns of vegetation, leading to defining biomes based on the objective, observable qualities of the vegetation based on current reality.