Leaf surface features of maize cultivars and response to foliar phosphorus application: effect of leaf stage and plant phosphorus status.

Soil phosphorus (P) application is the most common fertilisation technique but may involve constraints due to chemical fixation and microbial immobilisation. Furthermore, excessive P fertilisation leads to P runoff into water bodies, threatening ecosystems, so targeted foliar P fertilisation is an interesting alternative. This study aimed to determine the importance of leaf surface characteristics for foliar P uptake in P-deficient maize (Zea mays L.). The leaf surface of four maize cultivars was characterised by electron microscopy, Fourier transform infrared spectroscopy and contact angle measurements. Uptake of foliar-applied P by maize cultivars was estimated, measuring also leaf photosynthetic rates after foliar P spraying. Plants of cultivar P7948 were found to be wettable from the 4th leaf in acropetal direction, whereas other cultivars were unwettable until the 6th leaf had developed. Minor variations in stomatal number and cuticle composition were recorded, but no differences in foliar P absorption were observed between cultivars. Nevertheless, cultivars showed variation in the improvement of photosynthetic capacity following foliar P application. Phosphorus deficiency resulted in ultrastructural disorganisation of mesophyll cells and chloroplasts, which impaired photosynthetic performance, yet there was no effect on stomatal frequency and leaf wettability. This study provides new insights into the influence of P deficiency and cultivar on leaf surface characteristics, foliar P uptake and its effect on physiological processes. Understanding the relationships between leaf characteristics and P uptake allows a more targeted evaluation of foliar P fertilisation as an application technique and contributes to the understanding of foliar uptake mechanisms.

Incorporating biodiversity responses to land use change scenarios for preventing emerging zoonotic diseases in areas of unknown host-pathogen interactions.

The need to reconcile food production, the safeguarding of nature, and the protection of public health is imperative in a world of continuing global change, particularly in the context of risks of emerging zoonotic disease (EZD). In this paper, we explored potential land use strategies to reduce EZD risks using a landscape approach. We focused on strategies for cases where the dynamics of pathogen transmission among species were poorly known and the ideas of "land-use induced spillover" and "landscape immunity" could be used very broadly. We first modeled three different land-use change scenarios in a region of transition between the Cerrado and the Atlantic Forest biodiversity hotspots. The land-use strategies used to build our scenarios reflected different proportions of native vegetation cover, as a proxy of habitat availability. We then evaluated the effects of the proportion of native vegetation cover on the occupancy probability of a group of mammal species and analyzed how the different land-use scenarios might affect the distribution of species in the landscape and thus the risk of EZD. We demonstrate that these approaches can help identify potential future EZD risks, and can thus be used as decision-making tools by stakeholders, with direct implications for improving both environmental and socio-economic outcomes.

Leaf wettability is the main driver for foliar P uptake in P-deficient maize.

Foliar fertilisation is an alternative form of nutrient application, which is of particular interest for phosphorus (P), where the efficiency of soil fertilisation is low. However, the uptake of foliar-applied nutrients is insufficiently characterised. The aim of this study was to investigate the individual and combined significance of wettability, foliar fertiliser properties and surfactant on foliar P uptake in P-deficient maize (Zea mays L.). Sorption and desorption properties of two P salts used as foliar fertilisers (KH2PO4, K2HPO4) were determined with dynamic vapor sorption isotherms. Leaf surfaces and foliar spray depositions of two differently wettable maize cultivars were investigated by scanning electron microscopy and contact angle measurement. Phosphorus uptake was then linked to leaf and fertiliser solution properties and its effect on cell ultrastructure was characterised by transmission electron microscopy. Wettability was the key factor for P absorption, as all foliar fertilisers were taken up reaching a tissue-P level of adequately nourished plants. For unwettable leaves, only solutions with surfactant, especially the combination of surfactant and hygroscopic P salt (K2HPO4) were taken up. This study provides novel insights into the significance of leaf surface and fertiliser properties, which can thus contribute to an improvement of P fertilisation strategies.

High sensitivity of tropical forest birds to deforestation at lower altitudes.

Habitat conversion is a major driver of tropical biodiversity loss, but its effects are poorly understood in montane environments. While community-level responses to habitat loss display strong elevational dependencies, it is unclear whether these arise via elevational turnover in community composition and interspecific differences in sensitivity or elevational variation in environmental conditions and proximity to thermal thresholds. Here we assess the relative importance of inter- and intraspecific variation across the elevational gradient by quantifying how 243 forest-dependent bird species vary in sensitivity to landscape-scale forest loss across a 3000-m elevational gradient in the Colombian Andes. We find that species that live at lower elevations are strongly affected by loss of forest in the nearby landscape, while those at higher elevations appear relatively unperturbed, an effect that is independent of phylogeny. Conversely, we find limited evidence of intraspecific elevational gradients in sensitivity, with populations displaying similar sensitivities to forest loss, regardless of where they exist in a species' elevational range. Gradients in biodiversity response to habitat loss thus appear to arise via interspecific gradients in sensitivity rather than proximity to climatically limiting conditions.

A Systematic Review on Cannabinoids for Neuropathic Pain Administered by Routes Other than Oral or Inhalation.

The use of cannabis and cannabinoid products for the treatment of neuropathic pain is a growing area of research. This type of pain has a high prevalence, limited response to available therapies and high social and economic costs. Systemic cannabinoid-based therapies have shown some unwanted side effects. Alternative routes of administration in the treatment of neuropathic pain may provide better acceptance for the treatment of multiple pathologies associated with neuropathic pain. To examine the efficacy, tolerability, and safety of cannabinoids (individualized formulations, phytocannabinoids, and synthetics) administered by routes other than oral or inhalation compared to placebo and/or conventional medications in the management of neuropathic pain. This systematic review of the literature reveals a lack of clinical research investigating cannabis by routes other than oral and inhalation as a potential treatment for neuropathic pain and highlights the need for further investigation with well-designed clinical trials. There is a significant lack of evidence indicating that cannabinoids administered by routes other than oral or inhaled may be an effective alternative, with better tolerance and safety in the treatment of neuropathic pain. Higher quality, long-term, randomized controlled trials are needed to examine whether cannabinoids administered by routes other than inhalation and oral routes may have a role in the treatment of neuropathic pain.

Distribution of birds in Colombia.

BACKGROUND: 1. Colombia with 1941 known recorded bird species is one of the most species rich countries in the world. Efforts are necessary to conserve, study and promote sustainable use of this important taxonomic group throughout Colombia's vast territory.2. In an ideal world, informed decisions that are based on sound scientific information should be likelier to have successful outcomes. Nevertheless, there are barriers that make it difficult to access and use information in a timely fashion. Those same barriers impede the study, conservation and sustainable use of bird species in Colombia. On the other hand, given that there is good documentation about the ecology of a large number of species, information about the distribution of birds can be easily incorporated into decision-making processes, once this information becomes readily available in a consumable format using Geographic Information Sciences tools.3. In this context, the main objective of this paper is to present the first compilation of the current distribution of 1889 (97%) species of birds in Colombia, using expert criteria. The shapefiles were used to show the distribution and diversity of bird species in Colombia under both geopolitical and conservation geographic units.4. The information provided in this paper can be used as a baseline for a huge number of initiatives that aim to strengthen conservation efforts and improve knowledge about one the most unique taxonomic groups in the country. These range from land use planning strategies at the municipal or department scale to sustainable use of bird species - such as those initiatives related to bird watching - in Colombia. NEW INFORMATION: This study has considered three key aspects: 1) the importance of birds for Colombia's ecosystems, 2) the privileged place of Colombia in bird species richness and 3) the importance of data mobilisation in formats easily consumable by Geographic Information Systems (GIS) to facilitate the processes of informed decision-making. We present the first compilation - in shapefile format - for 1889 of the 1941 bird species recorded from Colombia. Using this novel collection, we showed the species richness of birds in Colombia's 33 Departments plus its Captial District (DPs), 1122 Municipalities (MNs), 58 protected areas (PAs), 39 Regional Autonomous Corporations (the authorities responsible within their respective jurisdictions for regulating the environment and renewable natural resources in Colombia; CARs) and 916 Collectively Titled Territories (including both indigenous reservations and afro-descendant communities; CTTs). In addition, we provide a list of known bird species richness for the above geographic units found in the available literature. The information provided here can be used as a baseline for a huge number of initiatives concerning the study, conservation and sustainable use of bird species present in Colombia, providing access to key features of bird distribution that should facilitate decision-making.

Differential reporting of biodiversity in two citizen science platforms during COVID-19 lockdown in Colombia.

The COVID-19 pandemic highlighted the potential of using data from long-term citizen science projects to answer questions about the impacts of unexpected events on biodiversity. We evaluate the suitability of data from the citizen science platforms iNaturalist and eBird to describe the effects of the "anthropause" on biodiversity observation in Colombia. We compared record distribution according to human footprint, sampling behaviors, overall and conservation priority species composition during the strictest phase of the COVID-19 lockdown in 2020 to the same periods in 2015-2019. Overall participation in both platforms during the lockdown was high when compared to previous years, but records were concentrated on highly-transformed regions, had lower sampling efforts, and fewer species were recorded. For eBird, species composition was similar to that observed in previous years, and records of species of conservation concern declined in proportion to the decrease in overall species richness across samples. For iNaturalist, the species pool sampled each year remained too dissimilar for comparisons. Once differences in observer behaviors are accounted for, data from these platforms can be used in unplanned comparisons of relatively common species, in regions with high levels of human transformation, and at narrowly defined geographical contexts. To increase the potential of citizen science to monitor rarer species, more natural areas, or be used in large-scale analyses, we need to build and strengthen more diverse networks of observers that can further promote decentralization, democratization, and cost-effectiveness in biodiversity research.

Listening to cities during the COVID-19 lockdown: How do human activities and urbanization impact soundscapes in Colombia?

Noise is one of the fastest growing and most ubiquitous type of environmental pollution, with prevalence in cities. The COVID-19 confinement in 2020 in Colombia led to a reduction in human activities and their associated noise. We used this unique opportunity to measure the impacts of noise on urban soundscapes, and explore the effects of urbanization intensity independently of human activity. We launched a community science initiative inviting participants to collect audio recordings from their windows using smartphones. Recordings were taken during severe mobility restrictions (April), and during a period of lightened restrictions (May-June). From the data collected, we measured changes in sound pressure levels (SPL), acoustic structure (soundscape spectro-temporal characteristics), and human perception between the two periods. A 12% increase in human activities had a detectable acoustic footprint, with a significant increase of SPL (2.15 dB, 128% increase), a shift towards dominance of low-frequency broadband signals, and a perceived dominance of human-made over wildlife sounds. Measured changes in SPL and acoustic structure were directly proportional to urbanization; however, perception of these changes was not. This gap may be associated with a masking effect generated by noise or a disconnect of humans from nature in large cities. The mobility restrictions created a chance to better understand the impacts of urbanization and human activities on the soundscape, while raising public awareness regarding noise pollution effects on people and wildlife. Information analyzed here might serve in urban planning in developing countries where urban expansion is occurring in a rapid, unplanned fashion.

Passive acoustic sampling data of the Colección de Sonidos Ambientales Mauricio Álvarez-Rebolledo - Instituto Humboldt (IAvH-CSA) during 2018 and 2019 in Colombia.

We present the dataset of passive acoustic sampling events deposited in the Colección de Sonidos Ambientales Mauricio Álvarez-Rebolledo at the Humboldt Institute (IAvH-CSA) during the years 2018-2019. The acoustic sampling events were generated from different projects, including Colombia Bio, Santander Bio, Boyacá Bio, Lisama, Riqueza Natural, and occasional events collected during this time. In total, 44,704 sampling events are deposited in the collection, corresponding to 1 minute of automatic recording sampled at a 44.1 kHz sampling rate and 16-bit resolution. The recording schedules correspond to 1 minute every 5, 10, or 30 min throughout the day, during 1 to 20 sampling days, across 79 localities in Colombia. The geographical coverage includes the departments of Bolívar, Boyacá, Caquetá, Cundinamarca, Meta, Santander, and Sucre. The present information was collected within the framework of the passive monitoring methodology established by the Humboldt Institute .

The importance of Legal Reserves for protecting the Pantanal biome and preventing agricultural losses.

Considering scenarios of future changes in land use have the potential to support policy-makers in drafting environmental laws to reconcile the demands of multiple land uses. The Pantanal, one of the largest wetlands in the world, has been undergoing rapid land use changes, and does not yet have any integrated environmental legislation on Legal Reserve for entire region (LR - minimum percentage of native vegetation required within private properties). The aim of this paper was to generate future vegetation loss scenarios for the Pantanal based on four LR values: (i) BAU: Business as usual, which considers existing laws: Native Vegetation Protection Law and State Decree; (ii) LRE: LR elimination owing to a bill recently proposed; (iii) LR50: which considers the bill proposing 50% of LR for the Pantanal; and (iv) LR80: our proposed levels of 80% of LR for the lowlands and 35% for the plateau (following values in the Amazon). Based on native vegetation loss from each scenario, we estimated the soil loss and sediment yield to rivers. Our results show that LRE would increase native vegetation loss in the Pantanal by as much as 139% when compared to the BAU, whereas increasing LR levels would reduce conversion values by 29% (LR80). Elimination of the LR would increase soil erosion and sediment production by up to 7% and 10%, respectively, compared to BAU. Based on native vegetation loss from each scenario, we estimated the soil loss and sediment yield to rivers with our data showing more than 90% of the sediment transported to the lowland originating from the plateau. The LR80 indicates a reduction in soil nutrient replacement costs of 10% compared to BAU, while in the LR50 these costs decrease by 1.5%, and in the LRE would increase of 8%. Our results show that abolishing current protections would have substantial impacts on avulsion processes, on several economic activities (tourism, fishery, cattle raising, etc.) and negative impacts for biodiversity conservation and would bring losses to agriculture in the Pantanal. Hence, our study brings clearly evidence of LR importance and need to expand it in this sensitive wetland.

Records of threatened bird and mammal species in Mato Grosso do Sul State, Brazil.

We conducted a detailed review of threatened bird and mammal occurrence records obtained from surveys across Mato Grosso do Sul, midwestern region of Brazil which has an extent of 357,145 km2, aiming to support environmental and biodiversity conservation initiatives, as strategic plans to protect threatened species in this region. We included all records of species categorized as threatened by the Brazilian and global red list of threatened species. We collected 760 records of threatened birds and mammals in Mato Grosso do Sul State, with 319 records of 40 bird's species and 441 records of 24 mammal's species. The status of the 40 bird species under de Brazilian threat category were as follow: 1 Critically Threatened (CR), 6 Endangered (EN), 11 Vulnerable (VU), 11 Near Threatened (NT), and 11 species only in the IUCN red list. Under the IUCN category for the bird´s species, were as follow: 3 EN, 13 VU, 18 NT, 5 Least Concern (LC) and 1 taxon has not yet been assessed for the IUCN Red List. Regarding mammal's species under the Brazilian threat category were as follow: 2 EN, 18 VU, 2 NT and 1 only in the IUCN red list. Under the IUCN status the species ranged from 2 EN, 6 VU, 10 NT, and 6 LC. Each record identified corresponds to the existence of at least one occurrence of threatened birds or mammals in a particular region. The records of threatened species belongs to the three biomes in the state: 269 mammal's records and 147 bird's records from Cerrado (Neotropical Savanna) biome, 117 mammal's records and 162 bird's records from Pantanal (Wetland) biome, and 55 mammal's records and 10 bird's records from Atlantic Forest biome. In addition, we also included in the dataset environmental information where each record was obtained. Supplementary Files 1- Records of Threatened Mammals_MS_Brazil and Supplementary File 2. Records of Threatened Birds of_MS_Brazil.

Warning signals of biodiversity collapse across gradients of tropical forest loss.

We evaluate potential warning signals that may aid in identifying the proximity of ecological communities to biodiversity thresholds from habitat loss-often termed "tipping points"-in tropical forests. We used datasets from studies of Neotropical mammal, frog, bird, and insect communities. Our findings provide only limited evidence that an increase in the variance (heteroskedasticity) of biodiversity-related parameters can provide a general warning signal of impending threshold changes in communities, as forest loss increases. However, such an apparent effect was evident for amphibians in the Brazilian Atlantic Forest and Amazonian mammal and bird communities, suggesting that impending changes in some species assemblages might be predictable. We consider the potential of such warning signs to help forecast drastic changes in biodiversity.

Brazil's worst mining disaster: Corporations must be compelled to pay the actual environmental costs.

In November 2015, a large mine-tailing dam owned by Samarco Corporation collapsed in Brazil, generating a massive wave of toxic mud that spread down the Doce River, killing 20 people and affecting biodiversity across hundreds of kilometers of river, riparian lands, and Atlantic coast. Besides the disaster's serious human and socioeconomic tolls, we estimate the regional loss of environmental services to be ~US$521 million per year. Although our estimate is conservative, it is still six times higher than the fine imposed on Samarco by Brazilian environmental authorities. To reduce such disparities between estimated damages and levied fines, we advocate for an environmental bond policy that considers potential risks and environmental services that could possibly be impacted by irresponsible mining activity. Environmental bonds and insurance are commonly used policy instruments in many countries, but there are no clear environmental bond policies in Brazil. Environmental bonds are likely to be more effective at securing environmental restitution than post-disaster fines, which generally are inadequate and often unpaid. We estimate that at least 126 mining dams in Brazil are vulnerable to failure in the forthcoming years. Any such event could have severe social-environmental consequences, underscoring the need for effective disaster-management strategies for large-scale mining operations.

Effect of moderate high temperature on the vegetative growth and potassium allocation in olive plants.

There is little information about the prolonged effect of a moderately high temperature on the growth of olive (Olea europaea L.). It has been suggested that when the temperature of the air rises above 35°C the shoot growth of olive is inhibited while there is any reference on how growth is affected when the soil is warmed. In order to examine these effects, mist-cuttings and young plants generated from seeds were grown under moderate high temperature (37°C) for 64 and 42days respectively. In our study, plant dry matter accumulation was reduced when the temperature of both the air and the root medium was moderately high. However, when the temperature of the root medium was 25°C, the inhibitory effect of air high temperature on plant growth was not observed. The exposure of both the aerial part and the root to moderate high temperature also reduced the accumulation of K+ in the stem and the root, the water use efficiency and leaf relative water content. However, when only the aerial part was exposed to moderate high temperature, the accumulation of K+ in the stem, the water use efficiency and leaf relative water content were not modified. The results from this study suggest that the olive is very efficient in regulating the water and potassium transport through the plant when only the atmosphere surrounding the aerial part is warmed up. However, an increase in the soil temperature decrease root K+ uptake and its transport to the aerial parts resulting in a reduction in shoot water status and growth.

Thresholds of species loss in Amazonian deforestation frontier landscapes.

In the Brazilian Amazon, private land accounts for the majority of remaining native vegetation. Understanding how land-use change affects the composition and distribution of biodiversity in farmlands is critical for improving conservation strategies in the face of rapid agricultural expansion. Working across an area exceeding 3 million ha in the southwestern state of Rondônia, we assessed how the extent and configuration of remnant forest in replicate 10,000-ha landscapes has affected the occurrence of a suite of Amazonian mammals and birds. In each of 31 landscapes, we used field sampling and semistructured interviews with landowners to determine the presence of 28 large and medium sized mammals and birds, as well as a further 7 understory birds. We then combined results of field surveys and interviews with a probabilistic model of deforestation. We found strong evidence for a threshold response of sampled biodiversity to landscape level forest cover; landscapes with <30-40% forest cover hosted markedly fewer species. Results from field surveys and interviews yielded similar thresholds. These results imply that in partially deforested landscapes many species are susceptible to extirpation following relatively small additional reductions in forest area. In the model of deforestation by 2030 the number of 10,000-ha landscapes under a conservative threshold of 43% forest cover almost doubled, such that only 22% of landscapes would likely to be able to sustain at least 75% of the 35 focal species we sampled. Brazilian law requires rural property owners in the Amazon to retain 80% forest cover, although this is rarely achieved. Prioritizing efforts to ensure that entire landscapes, rather than individual farms, retain at least 50% forest cover may help safeguard native biodiversity in private forest reserves in the Amazon.

Na+ accumulation in root symplast of sunflower plants exposed to moderate salinity is transpiration-dependent.

Twenty-day-old sunflower plants (Helianthus annuus L. cv Sun-Gro 380) grown hydroponically under controlled conditions were used to study the effect of transpiration on Na(+) compartmentalization in roots. The plants were exposed to low Na(+) concentrations (25 mM NaCl) and different environmental humidity conditions over a short time period (8.5 h). Under these conditions, Na(+) was accumulated primarily in the root, but only the Na(+) accumulated in the root symplast was dependent on transpiration, while the Na(+) accumulated in both the shoot and the root apoplast exhibited a low transpiration dependence. Moreover, Na(+) content in the root apoplast was reached quickly (0.25 h) and increased little with time. These results suggest that, in sunflower plants under moderate salinity conditions, Na(+) uptake in the root symplast is mediated by a transport system whose activity is enhanced by transpiration.

Na+ accumulation in shoot is related to water transport in K+-starved sunflower plants but not in plants with a normal K+ status.

Sunflower plants (Helianthus annuus L. cv Sun-Gro 380) grown in nutrient solutions with different K+ levels were used to study the effect of potassium status on water uptake, Na+ uptake and Na+ accumulation in the shoot. Changes in nutrient potassium levels induced evident differences in internal potassium content. When both low and normal-K+ plants were exposed to 22 degrees C and salinity conditions (25 or 50 mM NaCl) during a short time period (9h), water uptake in low-K+ plants was greater than in normal-K+ plants. In addition, K+ starvation favoured the Na+ uptake and the Na+ accumulation both in the root and in the shoot. When the plants were exposed to heat stress by a sharp increase of the temperature to 32 degrees C during the same period of time, the stimulating effect of K+ starvation on the water uptake was even greater. The high temperature increased Na+ uptake in both types of plants, but the Na+ accumulation in the shoot was only favoured in low-K+ plants. The results suggest that Na+ accumulation in the shoot is more dependent on the water uptake in low-K+ plants than in normal-K+ plants, and this effect could explain the greatest susceptibility to the salinity in K+-starved plants under high transpiration conditions, which are typical in dry climates.