Soil arthropod community responses to restoration in areas impacted by iron mining tailings deposition after Fundão dam failure.

In 2015, the failure of the Fundão dam in Mariana, Brazil released ~43 million m3 of iron mining tailings into the environment. Despite restoration initiatives in the following years, few studies-and most focused on revegetation-have evaluated the effectiveness of the restoration process in areas impacted by the disaster. We aimed to evaluate the responses of the arthropod community in areas impacted by iron mining tailings deposition from the Fundão dam that is in the restoration process. We defined sampling units in the riparian zone of the Gualaxo do Norte River, which is under restoration, and in a native not impacted riparian zone. We collected soil arthropods using pitfall traps and sampled environmental variables in the same sites. We used generalize least squares models (GLS) to test if the restored areas already presented values of arthropod diversity and functional group abundance similar to the reference area and to test which environmental variables are influencing arthropod diversity. We also tested how large the differences of arthropod community composition between the study areas and used the index of indicator species (IndVal) to verify which species could be used as an indicator of reference or restoration areas. The diversity of arthropods and the functional groups of detritivores and omnivores were higher in the native riparian zone. Understory density, soil density, organic matter content, and microbial biomass carbon were the environmental variables that significantly explained the diversity and species composition of arthropods. We show that restoration areas still have different soil arthropod diversity values and community composition when compared to reference areas. Evaluating the response of the arthropod community to the restoration process and long-term monitoring are essential to achieve a satisfactory result in this process and achieve a self-sustaining ecosystem.

Individual and combined toxicity of imidacloprid and two seed dressing insecticides on collembolans Folsomia candida.

The aim of this study was to examine the chronic toxicity of imidacloprid (IMI), clothianidin (CLO) and fipronil (FIP) as a single exposure, as well as binary mixtures of IMI with CLO or FIP toward collembolans Folsomia candida, which are fauna present in the soil. Chronic toxicity assays were performed following an ISO guideline in a Tropical Artificial Soil (TAS), and the influence on the number and growth of the juveniles produced were determined. The range of nominal concentrations used in the tests with the individual compounds was 0.08-1.28 mg/kg (IMI), 0.079-1.264 mg/kg (FIP) and 0.007-0.112 mg/kg (CLO), whereas the mixture assays were performed with half the value used in the tests with individual compounds. Based upon single exposures, IMI produced a similar impact of reducing reproduction by 50% (EC50 ranging from 0.74 to 0.85 mg/kg) compared to FIP (EC50 = 0.78 mg/kg), whereas CLO was the most toxic to F. candida (EC50 = 0.08 mg/kg). Their mixtures generally resulted in a diminished effect on reproduction, as evidenced by the higher EC50 values. In contrast, in the case of the IMI+FIP combination at high concentrations at the EC50 level, a synergistic effect on toxicity was observed. The single exposure to the three insecticides and the mixture of IMI-FIP also decreased the size of generated juveniles, which was evidenced by the reduction in the proportion of large juveniles and increased proportion of small juveniles. However, both binary mixtures (IMI-FIP and IMI-CLO) presented antagonistic effects as evidenced by less than expected reductions in growth. Data on the toxic effects of IMI in a mixture with other seed dressing insecticides to collembolans provides useful information to environmental risk assessors by diminishing the uncertainties on the ecological risk of exposure to pesticides, enabling soil management degradation by utilizing multiple insecticides.

Influence of temperature and soil moisture on the toxic potential of clothianidin to collembolan Folsomia candida in a tropical field soil.

Climate change can alter the toxic effects of pesticides on soil invertebrates. However, the nature and magnitude of the influence of climatic factors on clothianidin impacts in tropical soils are still unknown. The influence of increasing atmospheric temperature and the reduction in soil moisture on the toxicity and risk of clothianidin (seed dressing formulation Inside FS®) were assessed through chronic toxicity tests with collembolans Folsomia candida in a tropical field soil (Entisol). The risk of clothianidin for collembolans was estimated using the Toxicity-Exposure Ratio (TER) approach. Organisms were exposed to increasing clothianidin concentrations at 20, 25 and 27 °C in combination with two soil moisture conditions (30 and 60% of the maximum water holding capacity-WHC). The effect of temperature and soil moisture content on clothianidin toxicity was verified through the number of F. candida juveniles generated after 28 days of exposure to the spiked soil. The toxicities estimated at 25 °C (EC50_30%WHC = 0.014 mg kg-1; EC50_60%WHC = 0.010 mg kg-1) and 27 °C (EC50_30%WHC = 0.006 mg kg-1; EC50_60%WHC = 0.007 mg kg-1) were 2.9-3.0-fold (25 °C) and 4.3-6.7-fold (27 °C) higher than those found at 20 °C (EC50_30%WHC = 0.040 mg kg-1; EC50_60%WHC = 0.030 mg kg-1), indicating that clothianidin toxicity increases with temperature. No clear influence of soil moisture content on clothianidin toxicity could be observed once the EC50 values estimated at 30% and 60% WHC, within the same temperature, did not significantly differ. A significant risk was detected in all temperatures and soil moisture scenarios studied, and the TER values indicate that the risk can increase with increasing temperatures. Our results revealed that temperature could overlap with soil moisture in regulating clothianidin toxicity and reinforce the importance of including climatic factors in the prospective risk assessment of pesticides.

Are the Brazilian prevention values for copper and zinc in soils suitable for protecting earthworms against metal toxicity?

The current Brazilian copper (Cu) and zinc (Zn) prevention values (PV) for soil quality do not take into account the ecotoxicological impacts on soil organisms, which suggests these guiding values may not be protective of soil ecological trophic levels. This study assessed the acute (mortality) and chronic toxicity (reproduction), as well as the cumulative (bioaccumulation) potential of Cu and Zn (pseudo-total and available fractions) for earthworms Eisenia andrei in a Tropical Artificial Soil (TAS) and two tropical field soils (Oxisol and Alfisol). Toxicity data based on pseudo-total fractions were compared to PV. The Lowest Observed Effect Concentrations (LOEC) for the mortality endpoint were found at Cu and Zn concentrations higher than their PV (60 and 300 mg kg-1, respectively), regardless of the soil type. However, concentrations lower than PV reduced the reproduction of E. andrei by 20% (compared to the controls) for Cu in all tested soils (EC20s from 31.7 to 51.2 mg kg-1) and by 50% for Zn in Oxisol and Alfisol (EC50s = 225 and 283 mg kg-1, respectively). In TAS, only the EC20 (273 mg kg-1) for Zn was lower than PV. Increases of Cu in earthworm tissues occurred at concentrations higher than PV in all tested soils (LOEC values from 70 to 107 mg kg-1). The same was observed for Zn in TAS (LOEC = 497 mg kg-1), while in the field soils, the increases of Zn in earthworm tissues were lower than PV (LOEC = 131 and 259 mg kg-1 in Alfisol and Oxisol, respectively). We suggest the following: (1) The current Brazilian PV for Cu and Zn are not protective for earthworms (E. andrei) in the field soils tested; (2) PV derived from ecotoxicological assays in artificial soil cannot be representative for Brazilian field soils; (3) Using PV based on the pseudo-total fraction, without a soil-type normalizing factor, may limit the representativeness of this threshold for different soil types.

Size spectra of the edaphic fauna of typical Argiudol soils of the Rolling Pampa Region, Argentina.

Background: Soil-dwelling organisms populate the spaces-referred to as interstices-between the litter on the soil surface and the pores in the soil's organo-mineral matrix. These organisms have pivotal roles in soil ecosystem functions, such as the breakdown and decomposition of organic matter, the dispersal of bacterial and fungal spores and biological habitat transformation. These functions, in turn, contribute to broader ecosystem services like carbon and nutrient cycling, soil organic matter regulation and both chemical and physical soil fertility.This study provides morphological data pertaining to a range of soil organism sizes, specifically in Argiudol soils subjected to varying levels of agricultural activity in the Rolling Pampas Region, one of the world's most extensive and fertile plains.The primary focus is on soil microarthropods-namely, Acari (mites) and Collembola (springtails)-with a body width of less than 2 mm. These organisms constitute the majority of life in the intricate soil pore network. Additionally, the study documents species of earthworms (Oligochaeta, Crassiclitelata), recognised as ecosystem engineers for their ability to create physical channels in the soil matrix and to distribute organic matter. Moreover, the study includes measurements of morphological traits of soil-dwelling "macrofauna" (organisms with a body width greater than 2 mm), which are also implicated in various soil ecosystem functions. These include population regulation by apex predators, organic matter decomposition, biogenic structure formation, nutrient mobilisation and herbivory. New information: In this paper, we report both the geographical locations and individual measurements of key morphological traits for over 7,000 specimens, covering a range of soil-dwelling organisms. These include springtails (Entognatha, Collembola), mites (Arachnida, Acari), earthworms (Oligochaeta, Crassiclitellata) and additional soil macrofauna. All specimens were collected from typical Argiudol soils located in three distinct agricultural systems characterised by varying levels of land-use intensity. To our knowledge, no other dataset exists providing this information for the Argentinian Pampas.

Microplastic pollution on the soil and its consequences on the nitrogen cycle: a review.

Microplastics (MPs) correspond to plastics between 0.1 µm and 5 mm in diameter, and these can be intentionally manufactured to be microscopic or generated from the fragmentation of larger plastics. Currently, MP contamination is a complicated subject due to its accumulation in the environment. They are a novel surface and a source of nutrients in soils because MPs can serve as a substrate for the colonization of microorganisms. Its presence in soil triggers physical (stability of aggregates, soil bulk density, and water dynamics), chemical (nutrients availability, organic matter, and pH), and biological changes (microbial activity and soil fauna). All these changes alter organic matter degradation and biogeochemical cycles such as the nitrogen (N) cycle, which is a key predictor of ecological stability and management in the terrestrial ecosystem. This review aims to explore how MPs affect the N cycle in the soil, the techniques to detect it in soil, and their effects on the physicochemical and biological parameters, emphasizing the impact on the main bacterial groups, genes, and enzymes associated with the different stages of the N cycle.

A "Dirty" Footprint: Macroinvertebrate diversity in Amazonian Anthropic Soils.

Amazonian rainforests, once thought to be pristine wilderness, are increasingly known to have been widely inhabited, modified, and managed prior to European arrival, by human populations with diverse cultural backgrounds. Amazonian Dark Earths (ADEs) are fertile soils found throughout the Amazon Basin, created by pre-Columbian societies with sedentary habits. Much is known about the chemistry of these soils, yet their zoology has been neglected. Hence, we characterized soil fertility, macroinvertebrate communities, and their activity at nine archeological sites in three Amazonian regions in ADEs and adjacent reference soils under native forest (young and old) and agricultural systems. We found 673 morphospecies and, despite similar richness in ADEs (385 spp.) and reference soils (399 spp.), we identified a tenacious pre-Columbian footprint, with 49% of morphospecies found exclusively in ADEs. Termite and total macroinvertebrate abundance were higher in reference soils, while soil fertility and macroinvertebrate activity were higher in the ADEs, and associated with larger earthworm quantities and biomass. We show that ADE habitats have a unique pool of species, but that modern land use of ADEs decreases their populations, diversity, and contributions to soil functioning. These findings support the idea that humans created and sustained high-fertility ecosystems that persist today, altering biodiversity patterns in Amazonia.

Four new species of Parajapyx (Diplura: Parajapygidae) from Mexico with redescription of Parajapyx isabellae aztecus Silvestri.

Four new Mexican Parajapyx species are described: P. silvestrii sp. nov. differs from P. adisi Pagés by the presence of one ma macroseta on mesoscutum, metascutum and abdominal scutum I; P. pagesi sp. nov. differs from P. grassianus Silvestri in the arrangement and number of macrosetae on all abdominal scuta; P. brunocondei sp. nov. is characterized by the unique feature of 50 glandular setae on the subcoxal organs and femur with one macroseta; P. yunyanorum sp. nov. differs from P. reymi Pagés by having some reduced macrosetae on the mesoscutum and metascutum and one lp macroseta lacking on abdominal II to VII scuta. A redescription of P. isabellae aztecus Silvestri, 1948 is presented including additional characters not previously reported, such as complete body chaetotaxy and descriptions of leg III, antennae and cercus. An identification key is presented for Mexican species of Parajapyx.

Macro and mesofauna soil food webs in two temperate grasslands: responses to forestation with Eucalyptus.

We studied the effects of land use change from grassland to Eucalyptus spp. plantation on macro and mesofauna soil food webs in two sites in the Rolling Pampas. We expected to find differences in the parameters that characterize the structure of soil food webs, as the implantation of Eucalyptus implies changes in the characteristics of the resources and the microhabitat conditions. We also expected to find differences in the communities in terms of diversity, abundance, and species present. The treatments were: grasslands; 10-year-old Eucalyptus plantations and 20-year-old Eucalyptus plantations. Seasonal samplings were performed for the extraction of soil fauna in winter, spring, summer and autumn. For the analysis of food webs, we worked with "trophic species'': groups of organisms that have the same prey and the same predators. A total of 25 food webs were laid out using bibliographical information of feeding habits from the identified taxa. From each food web, we obtained a predator overlap graph, in which the consumers that share the same source or prey are linked by an arrow. In addition, the Shannon-Wiener index was calculated. We found that trophic species densities were different among the treatments: communities from grassland and the younger plantations were dominated by earthworms and other secondary decomposers, while the community in the older plantation showed a greater contribution of primary decomposers (Shymphyla, Isopoda and Diplopoda). No significant differences between treatments were found in the parameters that characterize the structure of soil food webs, i.e. connections number, number of trophic species nor connectivity. However, the diversity of the community was lower in the youngest plantations than in the other treatments, and it shows evidence of compartmentalization in the predator overlap graphs. Our findings suggest that the meso and macrofauna communities in the 10-years-old plantations represent a transition between the communities from grasslands and the oldest plantations. We conclude that the effects of forestation with Eucalyptus on soil fauna communities are evident through changes in functional groups rather than changes in the parameters that characterize the structure of soil food webs.

Epigeal fauna and soil attributes in a cover-cropped organic vegetable system / Fauna epígea e atributos do solo sob manejo com plantas de cobertura em cultivo orgânico

This study assessed the effect of cover crop biomass on the epigeal fauna of an organic eggplant (Solanum melongena L.) cropping system. A randomized block design was used, with four cover crop treatments: brachiaria, crotalaria, millet, and cocktail (brachiaria, crotalaria and millet). The epigeal faunal indices were determined at each plot. The epigeal fauna of a secondary forest site was also assessed for comparison. Epigeal individuals were collected using pitfall traps at two sampling periods (110 and 180 days after mowing cover crops). Soil samples were collected for determination of physical and chemic properties. 2032 individuals were captured in the first sampling and 3806 individuals in the second. The highest values of wealth in the first collection were observed in the millet and cocktail areas. Cluster analysis showed similarity of epigeal faunal groups between millet and brachiaria plots at the first sampling and between cocktail and crotalaria sites at the second sampling. Co-inertia analysis showed a significant covariance between epigeal fauna at the second sampling and soil properties. The cover crops management had a beneficial influence on the activity, wealth and ecological indexes, in both sampling periods. The positive association observed between epigeal faunal groups and soil physical and chemical properties demonstrates the efficiency of cover crops in improving soil quality in organic cropping systems.(AU)

O objetivo deste estudo foi avaliar o efeito da fitomassa de diferentes plantas de cobertura no desenvolvimento da comunidade da fauna epígea em área de cultivo orgânico de berinjela (Solanum melongena, L.). Foi adotado delineamento em blocos ao acaso, com quatro tratamentos de plantas de cobertura: braquiária, crotalária, milheto e coquetel (crotalária, braquiária e milheto), além de uma área de floresta secundária (FR). A fauna epígea avaliada por meio de armadilhas do tipo "pitfall traps" em dois períodos de coletas, aos 110 dias e aos 180 dias, após o corte das plantas de coberturas. Foram coletadas amostras de solo para análise de atributos físicos e químicos. Foram capturados 2032 indivíduos na primeira coleta e 3806 indivíduos na segunda coleta. Os maiores valores de riqueza na primeira coleta foram observados nas áreas milheto e coquetel. A análise de agrupamento mostrou similaridade dos grupos da fauna epígea entre o milheto e braquiária na primeira amostragem e entre o coquetel e crotalária na segunda amostragem. A co-inércia evidenciou covariância significativa entre a fauna epígea da segunda coleta e os atributos do solo. O manejo com plantas de coberturas influenciou de forma benéfica a atividade, riqueza e índices ecológicos, em ambos os períodos de amostragens. A associação positiva entre grupos da fauna e os atributos físicos e químicos mostram a eficiência das plantas de coberturas em cultivo orgânico na promoção de melhorias da qualidade do solo.(AU)

Epigeal fauna and soil attributes in a cover-cropped organic vegetable system / Fauna epígea e atributos do solo sob manejo com plantas de cobertura em cultivo orgânico

This study assessed the effect of cover crop biomass on the epigeal fauna of an organic eggplant (Solanum melongena L.) cropping system. A randomized block design was used, with four cover crop treatments: brachiaria, crotalaria, millet, and cocktail (brachiaria, crotalaria and millet). The epigeal faunal indices were determined at each plot. The epigeal fauna of a secondary forest site was also assessed for comparison. Epigeal individuals were collected using pitfall traps at two sampling periods (110 and 180 days after mowing cover crops). Soil samples were collected for determination of physical and chemic properties. 2032 individuals were captured in the first sampling and 3806 individuals in the second. The highest values of wealth in the first collection were observed in the millet and cocktail areas. Cluster analysis showed similarity of epigeal faunal groups between millet and brachiaria plots at the first sampling and between cocktail and crotalaria sites at the second sampling. Co-inertia analysis showed a significant covariance between epigeal fauna at the second sampling and soil properties. The cover crops management had a beneficial influence on the activity, wealth and ecological indexes, in both sampling periods. The positive association observed between epigeal faunal groups and soil physical and chemical properties demonstrates the efficiency of cover crops in improving soil quality in organic cropping systems.

O objetivo deste estudo foi avaliar o efeito da fitomassa de diferentes plantas de cobertura no desenvolvimento da comunidade da fauna epígea em área de cultivo orgânico de berinjela (Solanum melongena, L.). Foi adotado delineamento em blocos ao acaso, com quatro tratamentos de plantas de cobertura: braquiária, crotalária, milheto e coquetel (crotalária, braquiária e milheto), além de uma área de floresta secundária (FR). A fauna epígea avaliada por meio de armadilhas do tipo "pitfall traps" em dois períodos de coletas, aos 110 dias e aos 180 dias, após o corte das plantas de coberturas. Foram coletadas amostras de solo para análise de atributos físicos e químicos. Foram capturados 2032 indivíduos na primeira coleta e 3806 indivíduos na segunda coleta. Os maiores valores de riqueza na primeira coleta foram observados nas áreas milheto e coquetel. A análise de agrupamento mostrou similaridade dos grupos da fauna epígea entre o milheto e braquiária na primeira amostragem e entre o coquetel e crotalária na segunda amostragem. A co-inércia evidenciou covariância significativa entre a fauna epígea da segunda coleta e os atributos do solo. O manejo com plantas de coberturas influenciou de forma benéfica a atividade, riqueza e índices ecológicos, em ambos os períodos de amostragens. A associação positiva entre grupos da fauna e os atributos físicos e químicos mostram a eficiência das plantas de coberturas em cultivo orgânico na promoção de melhorias da qualidade do solo.

Epigeal fauna and soil attributes in a cover-cropped organic vegetable system / Fauna epígea e atributos do solo sob manejo com plantas de cobertura em cultivo orgânico

ABSTRACT: This study assessed the effect of cover crop biomass on the epigeal fauna of an organic eggplant (Solanum melongena L.) cropping system. A randomized block design was used, with four cover crop treatments: brachiaria, crotalaria, millet, and cocktail (brachiaria, crotalaria and millet). The epigeal faunal indices were determined at each plot. The epigeal fauna of a secondary forest site was also assessed for comparison. Epigeal individuals were collected using pitfall traps at two sampling periods (110 and 180 days after mowing cover crops). Soil samples were collected for determination of physical and chemic properties. 2032 individuals were captured in the first sampling and 3806 individuals in the second. The highest values of wealth in the first collection were observed in the millet and cocktail areas. Cluster analysis showed similarity of epigeal faunal groups between millet and brachiaria plots at the first sampling and between cocktail and crotalaria sites at the second sampling. Co-inertia analysis showed a significant covariance between epigeal fauna at the second sampling and soil properties. The cover crops management had a beneficial influence on the activity, wealth and ecological indexes, in both sampling periods. The positive association observed between epigeal faunal groups and soil physical and chemical properties demonstrates the efficiency of cover crops in improving soil quality in organic cropping systems.

RESUMO: O objetivo deste estudo foi avaliar o efeito da fitomassa de diferentes plantas de cobertura no desenvolvimento da comunidade da fauna epígea em área de cultivo orgânico de berinjela (Solanum melongena, L.). Foi adotado delineamento em blocos ao acaso, com quatro tratamentos de plantas de cobertura: braquiária, crotalária, milheto e coquetel (crotalária, braquiária e milheto), além de uma área de floresta secundária (FR). A fauna epígea avaliada por meio de armadilhas do tipo "pitfall traps" em dois períodos de coletas, aos 110 dias e aos 180 dias, após o corte das plantas de coberturas. Foram coletadas amostras de solo para análise de atributos físicos e químicos. Foram capturados 2032 indivíduos na primeira coleta e 3806 indivíduos na segunda coleta. Os maiores valores de riqueza na primeira coleta foram observados nas áreas milheto e coquetel. A análise de agrupamento mostrou similaridade dos grupos da fauna epígea entre o milheto e braquiária na primeira amostragem e entre o coquetel e crotalária na segunda amostragem. A co-inércia evidenciou covariância significativa entre a fauna epígea da segunda coleta e os atributos do solo. O manejo com plantas de coberturas influenciou de forma benéfica a atividade, riqueza e índices ecológicos, em ambos os períodos de amostragens. A associação positiva entre grupos da fauna e os atributos físicos e químicos mostram a eficiência das plantas de coberturas em cultivo orgânico na promoção de melhorias da qualidade do solo.

A remarkable Newportia from the Colombian Andes, with the proposition of a new subgenus (Scolopendromorpha, Scolopocryptopidae, Newportiinae).

A new monotypic subgenus Newportia (Andeocryptops) subgen. n is described based on 18 specimens of N. (A.) shelleyi sp. n. This form is endemic to the Colombian Andes showing the following unique combination of morphological features: very short and thin, a cylindrical and not segmented ultimate tarsus 2, a "spinning-spur" (see below) on the ultimate tarsus 1, short paramedian sutures close to the anterior and posterior margins of cephalic plate, a tibial lateral spur and a glandular pore fields in the ultimate femur. An identification key to the Newportia subgenera, as well as a key to the Ectonocryptops, Ectonocryptoides and Andeocryptops species are included.

Vegetation Pattern Modulates Ground Arthropod Diversity in Semi-Arid Mediterranean Steppes.

The ecological functioning of dryland ecosystems is closely related to the spatial pattern of the vegetation, which is typically structured in patches. Ground arthropods mediate key soil functions and ecological processes, yet little is known about the influence of dryland vegetation pattern on their abundance and diversity. Here, we investigate how patch size and cover, and distance between patches relate to the abundance and diversity of meso-and microarthropods in semi-arid steppes. We found that species richness and abundance of ground arthropods exponentially increase with vegetation cover, patch size, and patch closeness. The communities under vegetation patches mainly respond to patch size, while the communities in the bare-soil interpatches are mostly controlled by the average distance between patches, independently of the concurrent changes in vegetation cover. Large patches seem to play a critical role as reserve and source of ground arthropod diversity. Our results suggest that decreasing vegetation cover and/or changes in vegetation pattern towards small and over-dispersed vegetation patches can fast lead to a significant loss of ground arthropods diversity in drylands.

Colémbolos epiedáficos (Hexapoda: Collembola) en dos usos del suelo en la Altillanura colombiana / Epiedaphic springtails (Hexapoda: Collembola) in two soil uses of Colombia Eastern plains

Introducción: Los colémbolos epiedáficos participan en una amplia variedad de servicios ecosistémicos relacionados con la disponibilidad de nutrientes para las plantas, el almacenamiento y la regulación del agua, la estabilidad del suelo y el control de la humedad y el pH necesarios para la fertilidad de los suelos. Por esta razón, los colémbolos epiedáficos se consideran como organismos sensibles a los cambios generados en el uso del suelo. Objetivo: Comparar la fauna epiedáfica de dos tipos de vegetación introducida: pastos y plantaciones de Eucalyptus pellita en una región de los Llanos Orientales de Colombia. Métodos: La recolección de los colémbolos se realizó en áreas con cobertura de pastos introducidos y áreas forestadas de diferentes edades, con trampas pitfall que contenían Propilenglicol al 40 % como preservante; durante la época seca y la época húmeda. Se comparó la riqueza efectiva de géneros y se explicó su composición en función de 14 variables ambientales y dasométricas mediante un análisis de redundancia (RDA). Resultados: La colembofauna estuvo compuesta por Entomobryomorpha (62 %), Poduromorpha (17 %) y Symphypleona (21.1 %) representados en 12 familias y 26 géneros. La riqueza efectiva de géneros fue significativamente mayor en los pastos que en las plantaciones de E. pellita, pero la abundancia no disminuye significativamente, con excepción de las plantaciones jóvenes durante la época seca. El ensamblaje de colémbolos observados en el área se relacionó principalmente con el desarrollo de cobertura forestal, la disponibilidad de materia orgánica alrededor de la trampa y el contenido de Nitrógeno en el suelo. Conclusiones: Las áreas forestadas permitieron un ensamblaje de colémbolos, menos diverso que las pasturas, pero compuesto tanto por especies adaptadas a áreas abiertas, como de las áreas naturales boscosas circundantes.

Introduction: Epiedaphic springtails participate in a wide variety of services linked to plant nutrient availability, water storage and regulation, soil stability and control of moisture and pH necessary for soil fertility. Therefore, epiedaphic springtails are sensitive to soil use change. Objective: To compare diversity of epiedaphic springtails in two types of introduced vegetation: pastures and forestations of Eucalyptus pellita in a region of the Colombian eastern plans. Methods: Springtails were collected from introduced pastures and young, middle and mature forested areas of E. pellita, using pitfall traps containing Propylene Glycol (40 %) as preservative, during one dry and one wet season. Alfa and Beta diversity were compared at genus level, and community composition was explained using a set of 14 environmental variables through a redundancy analysis (RDA). Results: Epiedaphic springtails were represented by Entomobryomorpha (62 %), Poduromorpha (17 %) and Symphypleona (21.1 %), 12 families and 26 genera. Effective number of Collembola genera was lower in plantations but abundance was different only in young plantations during dry season. The variables related to forest coverage, soil organic matter coverage and Nitrogen better explained the observed genera assemblage. Conclusions: Forest plantations allowed an assembly of springtails less diverse than in pastures; but comprised both types of genera, those proper of open areas and those from surrounding natural wooded areas.

Diversidad de macro-invertebrados en sistemas silvopastoriles del sur de Quintana Roo, México

La diversidad de macro-invertebrados está relacionada con el estado de conservación del suelo, no obstante, la remoción de la cubierta vegetal natural para el establecimiento de sistemas ganaderos extensivos afecta su integridad. Una estrategia para la conservación de estos organismos es la implementación de sistemas silvopastoriles; no obstante, en el sureste de México la información aún es limitada. El propósito del presente estudio fue evaluar y comparar la riqueza y la abundancia de macro-invertebrados en cuatro agro-ecosistemas contrastantes: dos sistemas silvopastoriles conformados por Leucaena leucocephala y pastos asociados (i.e. Panicum máximum cv mombaza y Cynodon plectostachyus), un pastizal convencional de Brachiaria brizantha con árboles dispersos en baja densidad y una selva mediana subperennifolia. En cada sistema se delimitó una superficie de una hectárea y se estableció un transecto de 50 m de longitud en los que se colocaron cinco trampas de caída tipo pit-fall cada 10 m. El muestreo se realizó en febrero y mayo 2018 y en cada mes se realizaron cinco recolectas con intervalos de cinco días. Se recolectaron un total de 1 737 organismos pertenecientes a 10 órdenes de la clase Insecta y uno a la clase Gastropoda. Los sistemas con mayor abundancia de macro-invertebrados fueron el sistema de selva media subperennifolia (923 individuos) y el sistema silvopastoril de L. leucocephala con C. plectostachyus (354 individuos). Los órdenes más abundantes fueron: Hymenoptera, Coleoptera, Araneae y Orthoptera. La mayor diversidad de macro-invertebrados se presentó en los sistemas silvopastoriles de L. leucocephala con P. maximum (H'=1.58) y L. leucocephala con C. plectostachyus (H´=1.44). Los resultados encontrados muestran que los sistemas pecuarios manejados con componentes leñosos (árboles/arbustos) albergan una riqueza y abundancia importante de órdenes de macro-invertebrados en comparación con sistemas como selva mediana subperennifolia. Esta diversidad de macro-invertebrates podría contribuir a la integridad y funcionalidad de los agro-ecosistemas.

The diversity of macro-invertebrates is related to the state of disturbance of the soil, caused mainly by the land-use change for agricultural activities. A strategy for the conservation of these organisms is the implementation of diversified production systems such as silvopastoral systems. However, in the Southeast of Mexico, information is still limited. The aim of the present study was to evaluate and compare the richness, abundance and composition of macro-invertebrates in four contrasting agro-ecosystems: two silvopastoral systems made of Leucaena leucocephala and associated pastures (i.e. Panicum maximum cv mombaza and Cynodon plectostachyus), a pasture of Brachiaria brizantha with scattered trees in low density and, a medium-statured tropical dry forest. In each system, an area of one hectare was delimited and a transect of 50 m in length was established in which five pit-fall traps were placed every 10 m. The sampling was carried out in February and May of 2018 and in each month five collections were made with five-day intervals. A total of 1 737 organisms belonging to 10 orders of the class Insecta and one of the class Gastropoda were collected. The medium-statured tropical dry forest (923 individuals) and the silvopastoral systems of L. leucocephala with C. Plectostachyus (354 individuals) show the highest abundance of macro-invertebrates. The most abundant genera were: Hymenoptera, Coleoptera, Aracninae and Orthoptera. The higher macro-invertebrate diversity was found in the silvopastoral systems of L. leucocephala with P. maximum (H '= 1.58) and L. leucocephala with C. plectostachyus (H' = 1.44). The results show that livestock systems managed with woody components (trees or shrubs) are home of an important abundance and richness of macro-invertebrates, compared to tropical forests. This diversity of macro-invertebrates may contribute to the integrity and functionality of the agro-ecosystems.

Description of a new species of Willemia (Collembola: Hypogastruridae) from Panama with key to Willemia species occurring in the Americas.

Willemia panamaensis sp. nov. from Panama is described and illustrated. It is characterised by the presence of sensilla I (S2) and i1 (S9) on antennal segment IV, nine vesicles in the postantennal organ, and having dorsal setae and sensilla on abdominal segments V and VI twice as long than on segments I and II. A dichotomous key to species recorded from the Americas is provided. Reference is given to the DNA barcoding sequences of the new species.

Anderemaeus (Acari, Oribatida)-overview, three new species from South America and reassessment of Anderemaeidae supported by ontogeny.

Anderemaeus is a genus of Gondwanan soil-dwelling oribatid mites with seven of the eight previously known species being South American. We propose two new species from Chile- A. sidorchukae sp. nov. and A. dentatus sp. nov.-and a third from Ecuador, A. mataderoensis sp. nov. Juveniles of the former two species are described, comprising the first such data for Anderemaeidae: nymphs notably lack both exuvial scalps and centrodorsal gastronotic setae, and the opisthonotal gland opens on a distinct stalk. The generic description is revised and expanded and a key to known species of Anderemaeus is presented, including A. tridactylus comb. nov. We reject the inclusion of Anderemaeus in a broad concept of Caleremaeidae and the implied subsumption of Anderemaeidae, as there are no synapomorphies linking the taxa. Anderemaeus species possess derived traits-e.g. adult with circumpedal carina and nymphs with smooth cuticle and no scalp retention-that are absent from Caleremaeus but are shared with more derived brachypyline taxa. The higher classification of Anderemaeus is reviewed: an analysis of known traits is inconclusive regarding both the generic composition of Anderemaeidae and its superfamilial relationships. However, on the strength of juvenile morphology, we propose the transfer of Anderemaeidae to Gustavioidea.

The fungicide mancozeb affects soil invertebrates in two subtropical Brazilian soils.

Mancozeb is a dithiocarbamate non-systemic fungicide widely used to control fungal diseases of plants, commonly applied in apple orchards in Brazil. Instead of its common use, there are no reports about the risk to non-target organisms in Brazilian soils. We studied the risk of Mancozeb (in the commercial formulation Dithane® NT) for standard invertebrate species (Folsomia candida, Eisenia andrei and Enchytraeus crypticus) in two subtropical Brazilian soils, Oxisol and Ultisol, which are representative of apple production areas in Brazil. Reproduction and survival tests were carried out following ISO guidelines. Results showed that Mancozeb in Oxisol reduced the survival and reproduction of collembolans (LC50 54.43 and EC50 2.72 mg a.i. kg-1) and enchytraeids (LC50 6.97 and EC50 3.56 mg a.i. kg-1), in lowest values than those observed in Ultisol (F. candida LC50 > 1000 and EC50 > 100 mg a.i. kg-1; E. crypticus LC50 280.21 and EC50 29.67). Effects to E. andrei were similar in both soils and indicated a lower sensitivity of this species to Mancozeb. The species F. candida and E. crypticus were more sensitive than E. andrei. These results reinforce the need to include other soil organisms besides earthworms, using chronical endpoints and considering different types of soils, to better predict the risk of pesticides for subtropical soils.

A new termite species of the genus Dihoplotermes Araújo (Blattaria, Isoptera, Termitidae) from the Brazilian Amazonian rainforest / Uma nova espécie de térmita do gênero Dihoplotermes Araujo (Blattaria, Isoptera, Termitidae) da floresta Amazônica Brasileira

Dihoplotermes, a previously monotypic genus, is now composed of two species. Dihoplotermes taurus sp. nov., a new Termitinae termite species, is illustrated and described based on morphological characters from soldiers, workers, and imago. The new species is distinguished from Dihoplotermes inusitatus Araujo by having a spine-like protuberance with blunt apex on the postmentum, the presence of a spine on the gizzard and the absence of dimorphic soldiers. Furthermore, the internal morphological characteristics of a Dihoplotermes worker are described for the first time. Both internal and external morphological characters were used to improve the characterization of the species.(AU)

Dihoplotermes, que era um gênero monotípico, agora é composto por duas espécies. Dihoplotermes taurus sp. nov., uma nova espécie de cupim Termitinae, é descrita e ilustrada com base nos caracteres morfológicos dos soldados, operários e imago. A nova espécie se diferencia de Dihoplotermes inusitatus Araujo por apresentar uma protuberância em forma de espinho não pontiagudo no posmento, presença de um espinho na moela e ausência de soldados dimórficos. Além disso, são descritas pela primeira vez as características morfológicas internas de um operário de Dihoplotermes e utilizamos ambos caracteres morfológicos internos e externos para melhor caracterizar as espécies.(AU)