Agricultural Matrices Research Articles

Improving HPLC post-column derivatisation assays via In-Column Derivatisation

In column derivatisation (ICD) has been applied to antioxidants in food and agricultural matrices. ICD’s ability to reduce the post-column reaction loop volume is critical to investigate chromatographically before future applications are established. Due to the large number of post-column derivatisation (PCD) assays, this is out of the scope of this study to cover in one article. Hence, in this communication, we strictly focused on implementing ICD and its ability to reduce the post-column volume associated to the PCD’s reaction loop. Specifically, reversed phase (RP) separations where we take three different reaction schemes: (i) amino acids derivatised with ninhydrin, (ii) amino acids derivatised with o-phthalaldehyde (OPA), and (iii) sulfonamides derivatised with fluorescamine to exemplify three different case scenarios. This communication can be used as a practical guide for analysts. In the order of the workflow’s largest reduction in the reaction loop volume: (i) the amino acids derivatised with OPA, the ICD enabled the post-column volume to be reduced significantly from 500 µL down to 80 µL. This drastic reduction resulted in the chromatographic gain in performance – number of theoretical plates (N) (55–167 %) and peak height sensitivity (35–181 %). For the sulfonamides derivatised with fluorescamine, the ICD setup reduced the post-column volume from 500 µL down to 200 µL, and demonstrated significant improvements in efficiency – N (33–324 %), and peak height sensitivity (4–33 %). The amino acids derivatised with ninhydrin, the PCD reaction loop could not be decreased, and ICD demonstrated decreased signal to noise (S/N).

Distribution of 210Po activity and soil texture in agricultural soil.

The assessment of 210Po in agricultural soil matrices in different regions of Kerala and Karnataka was studied. The wet ash method was used to find the activity concentration of 210Po. The alpha activity was counted using a silver-activated zinc sulfide counter of 30% efficiency, and the activity was calculated. The average concentration of 210Po activity in soil samples ranged from 0.09 to 20.52Bqkg-1, with an average value of 4.47Bqkg-1. The soil texture was measured using the International Pipette method. Using the IBM Statistical Package of Social Science Software, the frequency distribution curve of 210Po is plotted and found to be lognormal. The data of 210Po are highly skewed, and the Kurtosis has a significant positive value. The 210Po activity concentrations are substantially within the World Health Organization's recommended limits.

Habitat Suitability in High Andean Butterflies: The Role of Land Cover in the Occurrence and Conservation of Species.

High Andean butterflies in northern South America are subject to landscape change processes. Our study used models to assess the habitat suitability of three Satyrinae species in the Upper Bogotá River Basin, Colombia. These three species include Pedaliodes polla (Thieme), Pedaliodes phaea (Hewitson), and Pedaliodes phaeina (Staudinger), the last two are endemic to Colombia. We used MaxEnt software to assess the habitat quality of these species, analyze the bioclimatic requirements that most influence them, and propose priority conservation areas. Our results indicated that, in most cases, the contribution of cover is more significant than 60%, so this variable determines the habitat capacity to support the species under study. We identified that the areas with suitable habitats are reduced with values less than or equal to 25% and are located in areas with a medium degree of intervention, which allows the species to occur. On the other hand, the climatic variables with the most significant contribution to the models were Temperature Seasonality and Precipitation of Driest Quarter (May-July). Conservation efforts must be focused on the most suitable areas, given the reduction in habitat for these species. Our research emphasizes the need to safeguard well-connected remnants of the high Andean forest and natural cover in agricultural matrices to counter the impact of agricultural expansion.

Rubber plantations are impermeable to an avian understory specialist in Sri Lanka

BackgroundUnderstanding how landscape characteristics affect animal movement is essential for conservation in human-dominated habitats. A fundamental question is how monoculture agroforests, including rubber and tea plantations, affect wildlife and its movement. Experimental translocations represent an important technique to assess animals’ habitat selection while moving through agricultural matrices, especially when complemented with observations of birds’ natural movements, and with “control” translocations, in which birds are moved within their natural habitat such as forest. Yet, experimental translocations have been little used for birds outside the Western Hemisphere.MethodsWe conducted experimental translocations and home-range measurements on an understory forest specialist, Brown-capped Babbler (BCBA, Pellorneum fuscocapillus), and a forest generalist, Tickell’s Blue Flycatcher (TBFL, Cyornis tickelliae). These species were studied in three rubber plantations, which also included some open areas mostly planted with tea, and in three forest reserves of Sri Lanka.ResultsFour of the five BCBAs translocated within disturbed habitats (rubber plantations) could not return to their capture locations. However, all four individuals within undisturbed habitats (forest reserves) successfully returned to their point of origin within 10.5 daytime hours. In contrast, all TBFLs returned to their capture locations in both disturbed (n = 7) and undisturbed habitats (n = 3) within 11.3 daytime hours. A Cox-proportional survival model demonstrated that the percentage of rubber cover decreased return time, similar to the effect of open-area cover. The home range surveys (n = 13 for BCBA, n = 10 for TBFL) revealed that very little of the birds’ natural home-ranges was covered by rubber (0.2% for BCBA, 13.1% for TBFL at 50% Kernel Density Estimates KDE). Home range size for BCBA was approximately half the size in disturbed habitats compared to undisturbed ones, although there was no significant difference between habitats for TBFL.ConclusionsWe conclude that rubber plantations can be impermeable to understory habitat specialist birds, and even generalist species may avoid them long-term. Our findings highlight the potential utility of strips of native vegetation, particularly those featuring understory layers, as corridors to facilitate the movement of forest specialists in landscapes dominated by rubber plantations and other types of disturbed habitats.

Saffron-cowled Blackbirds’ reduced nest success in Argentina’s agricultural land highlights the importance of non-agricultural habitat for its conservation

Abstract The Saffron-cowled Blackbird (Xanthopsar flavus) is a globally endangered icterid endemic to the southern South American grasslands. Temperate grasslands are among the most threatened ecosystems in South America due to their high rate of land use change. In northeastern Argentina, over the last century, the conversion of natural grasslands to livestock farming, croplands, and afforestation has resulted in significant losses of breeding habitat for the Saffron-cowled Blackbird. Consequently, it has suffered severe populational declines, and its remaining populations are fragmented. In order to understand the impact of agricultural systems on the Saffron-cowled Blackbird populations, we studied its breeding biology (clutch size, hatching success, nestling production, and fledgling success) and the main parameters that influence nest survival rate in five breeding habitat types. During the breeding seasons of 2015 to 2019, we located nests and monitored their fate. We found that the cumulative probability of nest survival over the entire nesting cycle (i.e. laying, incubation, and chick rearing) was 0.06, and was lower for nests situated in grazed land covers. Conversely, nest survival was greater in breeding sites without agricultural use, particularly in marshes. Predation was the main cause of nest failure (76%), followed by brood parasitism (10%), and trampling by cattle and agricultural machinery (6%). Brood parasitism rates were higher in grazed paddocks, contributing together with predation to the failure of nests in this habitat. Our findings indicate a negative impact of livestock ranching on Saffron-cowled Blackbird reproduction. Non-agriculture habitats, such as wetlands and flooded areas, are important as refuges for nesting. Thus, the creation of breeding refuges (non-productive sites) within agricultural matrices, in association with biodiversity-friendly agricultural practices, is crucial to ensure the Saffron-cowled Blackbird’s maintenance.

Comparative Review of Instrumental Techniques and Methods for the Analysis of Microplastics in Agricultural Matrices

Microplastics (MPs) are ubiquitous and evasive in nature. They can be found in complex agricultural matrices like soil and compost. In the literature, extracting MPs from soil is more prevalent; nonetheless, the same instruments in extraction in soil samples can also be used to assess MPs in compost despite the high levels of organic material. MPs in agricultural environments have recently become a focus of research due to their status as emerging pollutants. However, the lack of standardized instruments and techniques for analysis is a major challenge in assessing MPs. Despite this limitation, this review article identified and suggested some important factors to consider when selecting suitable methods or instruments for MP analysis. This article also categorized instrumental analysis in MP studies as destructive and non-destructive and highlighted the advantages and disadvantages of methods and instruments such as visual inspection, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy (RS), and Scanning Electron Microscope (SEM). These highlights will provide researchers with a useful guide to help them choose the most appropriate method and instrumentation technique for their MP analytical research. Additionally, the article discusses the combination of two or more of these analytical instruments to improve efficiency.

UiOL@AIEgens-assisted lateral flow immunosensor for the ultrasensitive dual-modal point-of-care detection of aflatoxin B1

Aflatoxin B1 (AFB1) contamination in food has attracted worldwide attention. The sensitive detection of AFB1 is vital for ensuring food quality and safety. This study developed an ultrasensitive signal-enhanced lateral flow immunosensor (LFIS) based on the functionalized zirconium metal-organic framework (MOF) of a UiO linker enriched with abundant aggregation-induced emission luminogen (UiOL@AIEgens) probes for the rapid dual-modal point-of-care (POC) determination of AFB1. Using UiO MOFs with numerous active sites as the carrier facilitated abundant AIEgens enrichment on the surface. After coupling with enough anti-AFB1 monoclonal antibodies (mAbs), the green-emissive UiOL@AIEgens-mAbs probes with high specificity and remarkably-enhanced fluorescence responses were obtained to competitively capture target AFB1 in the standard or sample solution and AFB1 antigen immobilized on the test (T) line of the POC LFIS. Under optimum conditions, the LFIS was capable of visual qualitative and smartphone-assisted dual-modal determination of target AFB1 within 7 min. Detection occurred in a range of 0.01–5 ng/mL at an ultra-low detection limit of 0.003 ng/mL, which was 300- and 600-fold lower than traditional immunoassays and the maximum limit set by the European Union, respectively. Moreover, the feasibility and robustness of the LFIS platform were assessed by detecting AFB1 in maize and lotus seed samples with average recoveries of 94.3–109.0%. The developed UiOL@AIEgens-based POC LFIS can be used for ultrasensitive, reliable, on-site detection in food. This study provides a new method for the real-time monitoring of AFB1 and other harmful contaminants in food and more complex matrices.

Comparative toxicity of two neonicotinoid insecticides at environmentally relevant concentrations to telecoprid dung beetles

Dung beetles (Coleoptera: Scarabaeinae) frequently traverse agricultural matrices in search of ephemeral dung resources and spend extended periods of time burrowing in soil. Neonicotinoids are among the most heavily applied and widely detected insecticides used in conventional agriculture with formulated products designed for row crop and livestock pest suppression. Here, we determined the comparative toxicity of two neonicotinoids (imidacloprid and thiamethoxam) on dung beetles, Canthon spp., under two exposure profiles: direct topical application (acute) and sustained contact with treated-soil (chronic). Imidacloprid was significantly more toxic than thiamethoxam under each exposure scenario. Topical application LD50 values (95% CI) for imidacloprid and thiamethoxam were 19.1 (14.5–25.3) and 378.9 (200.3–716.5) ng/beetle, respectively. After the 10-day soil exposure, the measured percent mortality in the 3 and 9 µg/kg nominal imidacloprid treatments was 35 ± 7% and 39 ± 6%, respectively. Observed mortality in the 9 µg/kg imidacloprid treatment was significantly greater than the control (p = 0.04); however, the 3 µg/kg imidacloprid dose response may be biologically relevant (p = 0.07). Thiamethoxam treatments had similar mortality as the controls (p > 0.8). Environmentally relevant concentrations of imidacloprid measured in airborne particulate matter and non-target soils pose a potential risk to coprophagous scarabs.

Early spring orchard pollinators spill over from resource‐rich adjacent forest patches

Abstract Pollinator communities are more abundant and diverse in agricultural matrices with more natural habitat, although the reasons for these correlations remain unclear. It is possible that forest fragments and edges provide resources for pollinators in important early weeks of spring, after which time those insects can then ‘spill over’ into crops such as apple orchards during bloom. To explore how forest edges may feed and therefore promote flower visitor communities in adjacent agricultural habitats, we sampled springtime pollinators in nine orchards and their adjacent forest edge canopies and understories. We identified pollen consumed by pan‐trapped bees and flower flies to assess if pollinators ate pollen where they were caught, and if their diets similarly ‘spill over’ from forest to orchard. We further explored sex differences in habitat usage. Our spatially replicated sampling found that bee and flower fly abundance peaks first in the forest understorey, then in the forest canopy and finally in the orchard. Analysis of digestive tracts showed significant usage of forest canopy pollen throughout the spring, especially before apple bloom. Pollinators had often eaten pollen from a different habitat than the one in which they were caught, suggesting frequent movement between habitats. Digestive tract pollen is an underused but powerful avenue for ecological insight. In Andrena, which are important orchard pollinators and one of the most abundant wild bee taxa in this study, male bees were primarily found in the woods but not the orchards where conspecific females were later active. Synthesis and applications: Forested areas, especially forest canopy trees, provide large amounts of early spring resources that facilitate build‐up and spillover of wild pollinator populations into apple orchards during bloom. Forests also provide critical habitat for male bees, which were rarely found in orchards. Despite their importance for bee reproduction, the needs of male bees are usually not considered in conservation planning. Overall, our data indicate that ensuring there is adequate forest habitat adjacent to orchards can improve the long‐term sustainability of pollinator populations that provide essential crop pollination services.

Tree-based ecosystem services supply and multifunctionality of church forests and their agricultural matrix near Lake Tana, Ethiopia

Ecosystem services (ES) are the connection between nature and society, and are essential for the well-being of local communities that depend on them. In Ethiopia, church forests and the surrounding agricultural matrix supply numerous ES. However, the ES delivered by both land use types have not yet been assessed simultaneously. Here we surveyed both church forests and their agricultural matrices, aiming to quantify, compare and unravel the drivers underlying tree-based ES supply, density and multifunctionality. We found that almost all church forests and half of the agricultural matrices provided high ES densities. ES multifunctionality was higher in the agricultural matrices, suggesting that people deliberately conserve or plant multifunctional tree species. Furthermore, the supply of all categories of ES was positively correlated with church forest age (p-value < 0.001) in the agricultural matrix, while the extent of church forest was positively correlated with the density of all categories ecosystem services score in the church forests (p-value < 0.001). Our results can be used to prioritize conservation efforts at sites that provide high levels of ES supply, ES density and ES multifunctionality, and to prioritize restoration efforts at sites with low levels thereof.

Genetic Diversity of Paryphthimoides poltys (Nymphalidae: Satyrinae: Euptychiina) in a Fragmented Agricultural Landscape in the Brazilian Atlantic Forest

The species-level response of organisms to habitat loss and fragmentation relies on their dispersal ability, as well as trophic level, degree of habitat specialization and landscape structure. For butterflies, community composition is affected by the landscape configuration, by the surrounding habitat and by the matrix composition scattered around forest fragments, whereas higher dispersal ability is a significant advantage for persistence in highly fragmented landscapes. However, species of butterflies are highly variable in their dispersion capabilities, which affects their genetic variability as a whole and in how it is distributed within and between subpopulations in remaining fragments. In the present study, the genetic variability in subpopulations of Paryphthimoides poltys distributed through forest fragments was evaluated. Low diversity and the absence of genetic structure was found through eight fragments of semideciduous Atlantic Forest, surrounded by agricultural matrices, in Southeastern Brazil. Although P. poltys was the most common species found in the area in a previous study, its high abundance was not accompanied by high genetic variability. The species is usually found flying in forest edges and open environments and, although low, its genetic variability is expected to be preserved even if some of the investigated forest fragments are lost in the near future.

Early stages of crop expansion have little effect on farm-scale vegetation patterns in a Cerrado biome working landscape

In addition to protected areas, sustainable working landscapes are key to successful biodiversity conservation. Yet such landscapes are threatened by rapid crop expansion, in particular in Brazil. In this context, this study explores the influence of farming systems on farm-scale vegetation patterns around the Serra da Bodoquena National Park in Mato Grosso do Sul. To collect data on farming systems and how they are evolving, we conducted interviews at 40 farms covering 120,000 ha, including eight farms with land within the national park. To assess vegetation patterns, we conducted pixel-wise and landscape analyses based on MapBiomas land cover maps from which we calculated seven metrics over the 2009–2019 period. Using multivariate methods, we identified the activities that differentiated farming systems, isolating five farm types with contrasting involvement in crop cultivation and ranching. We found that most farm-scale landscape metrics were only weakly influenced by farming systems. Temporal analyses and interviews suggested that biophysical and legislative contexts limit crop expansion, which mainly occurred at the expense of old pastures and did not directly impact forest proportion within farms. As a consequence, crop expansion in the region seemed to mainly affect small tree patches in pasture areas, making its effect on vegetation patterns barely detectable with 30-m resolution imagery. These findings suggest that rather than focusing solely on deforestation, monitoring the dynamics of wooded pastures with high-resolution images is crucial to assess the early effects of crop expansion on vegetation patterns and to ensure the conservation of biodiversity-friendly agricultural matrices around protected areas in Brazil.

Agroforestry orchards support greater avian biodiversity than monoculture oil palm and rubber tree plantations

The suitability of agricultural matrices to support biodiversity, including birds, varies depending on agricultural land-use. In Southeast Asia, monoculture plantations of oil palm and rubber tree have replaced the native rainforests and displaced forest biodiversity. Compared to such single functionality plantations, agroforestry orchards may provide a more complex habitat for biodiversity via polyculture and less intensive farming practices. However, little is known about the conservation value of agroforestry orchards for biodiversity. Here, we investigated the effects of different agricultural habitats on avian biodiversity in Peninsular Malaysia. Using point count method, we assessed bird community in three focal agricultural habitats (i.e., agroforestry orchards, oil palm, and rubber tree plantations). From 6,248 bird encounters, we recorded 110 species comprising 43 families. Bird species richness and abundance were significantly greater in agroforestry orchards than the other two agricultural habitats. Bird abundance was similar in oil palm and rubber tree plantations, but the latter supported significantly more species. Agricultural land-use type had significant effects on certain bird dietary groups (i.e., frugivores, insectivores, omnivores, and granivores). Overlap in bird species composition between habitats was rather evident, though some bird groups were more represented than others in the different habitat types. Our key findings may imply the importance of habitat heterogeneity in relation to vegetation structural complexity (as commonly found in fruit orchards) on farmland birds. Our data suggest that incorporating diverse native fruit trees into large-scale monoculture plantations could promote habitat heterogeneity and floristic composition, which can improve bird conservation and ecosystem services (e.g., pest insect control).

Live Fences as Refuges of Wild and Useful Plant Diversity: Their Drivers and Structure in Five Elevation Contrast Sites of Veracruz, Mexico

Background and Research One noteworthy element found throughout the tropical anthropogenic mosaic is the live fence, which is established within agricultural matrices and its structure within the landscape retains ecological processes, but few are recognized as elements of biological and cultural conservation. Methods In this study, we have researched plant diversity and anthropic management of live fences in five sites surrounded by contrasting vegetation references: Tropical evergreen forest; tropical deciduous forest; cloud forest; and pine–oak and pine forests. We recorded the type of management by interviews with peasants. We established thirty 2 × 50 m transects within each site and sampled two strata: trees and saplings. Also, we documented seed dispersal mechanism, life form, local use, and origin of each species. Importance Value Index and diversity metrics were estimated for each site. Results 253 plant species were registered (181 genera/74 families). While fences associated with the tropical deciduous forest showed the greatest species richness (109 species), the pine forest fences showed the lowest richness (21 species). Zoochory was the main type of seed dispersal mechanism. Conclusions Independent to the site and the altitude, the configuration of living fences is structured by three processes: the selection of the initial trees, the availability of the arrival of zoochory species, and the tolerance of the owners for the plant species. Implications for Conservation Based on our results, live fences can be considered important tools for landscape management in Mexico.

Forest cover and proximity to forest affect predation by natural enemies in pasture and coffee plantations differently

Biological pest control is one of the key services from which agricultural production benefits. Despite being a well-studied ecosystem service, the potential of different matrices in shaping natural enemy contributions to pest predation is not yet clear. We used an experimental approach with predation experiments to investigate whether matrices with different degrees of structural similarity to the native forest (coffee and pasture) modulated the effects of forest cover and forest proximity on predation rate from different natural enemies. The effects of landscape structure on predation rates varied with natural enemy response to matrix type. Predation rates by arthropods (the main natural enemy acting in both matrices) were higher in coffee plantations and were positively and negatively affected by landscape and local forest cover, respectively. Predation rates by birds were higher near the forest in both matrices and two times higher in coffee plantations than in pastures. Regardless of natural enemy identity, predation rates inside agricultural matrices were higher in low-contrasting matrices, and increase with forest cover and proximity to forest. Given the clear importance of matrix type in modulating the effects of forest cover and forest proximity on predation rates, we recommend that agricultural management consider reducing habitat-matrix contrasts while increasing contact and habitat cover in the landscape to improve biological pest control. Among matrix management strategies, we recommend within-farm actions that would lead to greater matrix heterogeneity and permeability, along with an increase in landscape habitat cover, such as more sustainable and wildlife-friendly agricultural systems and the restoration of protected areas within farms.

Diet Composition of Bats in a Human-Modified Tropical Landscape

Human-modified landscapes are often composed of small and isolated natural habitat fragments immersed in agricultural and urban matrices. Within them, ecosystem services provided by wildlife, such as pest insect suppression, may decrease or even be lost leading to a substantial increase in agricultural production costs. Pest insect suppression by bats has been identified as an essential ecosystem service but remains poorly investigated. For example, we still lack a basic understanding of the proportion of pest insects that comprises the diet of many bat species. Here, we explored the diet composition of eight Brazilian bat species (78 individuals) in a human-modified landscape through the analysis of stable carbon (13C) and nitrogen (15N) isotopes. Bats were categorised into guilds: open-space aerial insectivores, narrow-space gleaning frugivores, or narrow-space gleaning nectarivores. We divided the insects collected into three groups depending on their δ13C values: forest, mixed, and pest insects. We found that open-space insectivorous bats had the highest proportion of insects in total in their diet — consuming primarily from the forest group (56%) and the pest group (34%). Interestingly, narrow-space gleaning frugivores also consumed pest insects (almost 20%). The narrow-space gleaning nectarivores had traces of insects in their diet, yet the actual proportion was inconclusive. Even though bats were from different guilds, with diets consisting mainly of plants and insects, the δ15N indicated that they fitted to similar trophic levels, as secondary consumers. Therefore, the trophic level of nectarivorous and frugivorous bats showed a more generalist diet than previously assumed. The proportion of forest insects in the diet of open-space aerial insectivores may indicate the importance of small forest patches as food resources for wildlife such as the ones included in human-modified landscapes. The bats' contribution to this ecosystem service could improve the economic conservation value of Neotropical bats in human-modified landscapes.

Recent Advances in Spectroscopic Techniques for the Analysis of Microplastics in Food.

Microplastic pollution has become a worldwide concern in aquatic and terrestrial environments. Microplastics could also enter the food chain, causing potential harm to human health. To facilitate the risk assessment of microplastics to humans, it is critically important to have a reliable analytical technique to detect, quantify, and identify microplastics of various materials, sizes, and shapes from environmental, agricultural, and food matrices. Spectroscopic techniques, mainly vibrational spectroscopy (Raman and infrared), are commonly used techniques for microplastic analysis. This review focuses on recent advances of these spectroscopic techniques for the analysis of microplastics in food. The fundamental, recent technical advances of the spectroscopic techniques and their advantages and limitations were summarized. The food sample pretreatment methods and recent applications for detecting and quantifying microplastics in different types of food were reviewed. In addition, the current technical challenges and future research directions were discussed. It is anticipated that the advances in instrument development and methodology innovation will enable spectroscopic techniques to solve critical analytical challenges in microplastic analysis in food, which will facilitate the reliable risk assessment.

Differential effect of agricultural matrices on bamboo abundance in forest fragments

ABSTRACT Bamboos, abundant in tropical forests, have high potential to dominate disturbed areas due to their high vegetative growth rate and preference for disturbed habitats. However, there are no studies exploring the influence of forest patch characteristics and anthropogenic land-use on bamboo populations. We investigated the influence of landscape matrix characteristics on the abundance of two bamboo taxa (Merostachys sp. and Parodiolyra micrantha) across two different spatial scales: 600 m (113 ha) and 1000 m (314 ha). We sampled the edge of 15 forest fragments (from 20.3 to 116.5 ha) in a highly disturbed landscape in Alfenas, Brasil. Only P. micrantha abundance was influenced by landscape metrics: positively by the percentage of sugarcane and coffee plantations around a forest fragment at 600 m, and negatively by the percentage of pasture at 1000 m. We suggest that cattle presence and/or the edge effect intensified by the adjacent pasture matrices could explain the negative effect of pasture, and that the disturbance caused by sugarcane and coffee plantations might explain the positive influence on P. micrantha abundance, a generalist and competitive understory species. Our results could help decision makers in their attempts to control bamboo populations and manage the landscape around forest fragments.

Parmotrema tinctorum as an indicator of edge effect and air quality in forested areas bordered by intensive agriculture.

Pollutants inhibit thallus growth and development or alter the metabolism and associated anatomical and morphophysiological characteristics of lichens. Since agricultural matrices can act as sources of pollution by dispersing agrochemicals to vegetation fragments, this study tested the hypothesis that Parmotrema tinctorum can serve as the indicator of edge effect in such fragments. In other words, we assumed the impact of pollutant accumulation to be greater at the vegetation edges and explored the utility of this lichen as a bioindicator of pollutants dispersed from agricultural matrices. Differences in the anatomical layers of P. tinctorum thalli sampled from the edge and center of four vegetation fragments (CER, SSF, SSC, and ENP) were evaluated, and the effects of agricultural matrices on macro- and micronutrient levels, heavy metal levels, and photosynthetic pigment content were analyzed. Anatomical layers were thicker in P. tinctorum thalli from the edges of SSC and ENP, indicating the need for photobiont protection at these sites. Edge effect was observed on Al accumulation in the thallus, indicating dispersion of this metal from agricultural matrices and its greater impact in the edge populations. Edge effect was also evident on photosynthetic pigment content, macro- and micronutrient levels, and heavy metal concentration in the thallus, and the values reflected high ecological imbalance currently verified at the edge of ENP, an area of permanent protection. In areas within ENP, chlorophyll a/b ratio reflected stress factors acting on the thallus, indicating that even legally protected areas are not free from the impact of atmospheric pollutants. P. tinctorum may serve as an effective indicator of edge effects and may be used for biomonitoring pollutant dispersion from agricultural matrices.

Characterization of Riparian Tree Communities along a River Basin in the Pacific Slope of Guatemala

Ecosystem conservation in Mesoamerica, one of the world’s biodiversity hotspots, is a top priority because of the rapid loss of native vegetation due to anthropogenic activities. Riparian forests are often the only remaining preserved areas among expansive agricultural matrices. These forest remnants are essential to maintaining water quality, providing habitats for a variety of wildlife and acting as biological corridors that enable the movement and dispersal of local species. The Acomé river is located on the Pacific slope of Guatemala. This region is heavily impacted by intensive agriculture (mostly sugarcane plantations), fires and grazing. Most of this region’s original forest is now restricted to forest remnants concentrated along the riverbank. However, the botanical composition and species diversity of the riparian communities has not been characterized. This baseline information is essential to develop restoration strategies and management plans. This study aimed to characterize the riparian tree communities along the Acomé riverbank by systematically collecting herbarium specimens and photographic material for trees over 10 cm DBH (diameter at breast height). Cluster analysis was used to identify the main riparian communities, and diversity indices were calculated for each community. A total of 115 tree species were identified, belonging to 91 genera and 43 families. The cluster analysis suggested the presence of four riparian tree communities along an altitudinal gradient. Rhizophora mangle, Cecropia obtusifolia, Guazuma ulmifolia, and Brosimum costaricanum were the dominant species of the identified communities. This research will support ongoing restoration efforts and biological connectivity plans in this region.