Rhinodrilus priscilae and Andiorrhinus (Amazonidrilus) caxiuana (Crassiclitellata, Rcrilidae) two new species from Caxiuanã National Forest.

The amazon forest is the habitat of a high species diversity of invertebrates and unfortunately the real richness had been underestimated. Earthworms' inventories had been poor because difficult to describe new species. This study adds new records to eastern amazon of two new species belong Rhinodrilus and Andiorrhinus genera. R. priscilae n. sp. is another rare specimen of the genre having two pair of prostatoid glands. A. (Amazonidrilus) caxiuana differ of other species in size, the intestinal origin is in XXVIII and also has only one glandular mass associated to spermatheca.

An annotated checklist and distribution of earthworms from Venezuela (Megadrili: Crassiclitellata).

An earthworm checklist has produced 78 nominal taxa (species/subspecies) of earthworm reported to date in Venezuela. The list of nominal taxa was obtained through literature review and the distribution maps were plotted by ecoregion. The 78 species/subspecies are divided into 24 genera and 6 families. Native earthworm species were more widely distributed than peregrine and exotic and are more associated with the conserved areas. Exotic species had been collected mainly in the north of the country in areas with at least some disturbance history. The peregrine species P. corethrurus is also widely distributed but with a preference for disturbed areas or related to its native natural grassland condition near the Guayana's shield. This is the first accurate assessment of Venezuela's earthworm species and subspecies in the last 14 years.

Additions to earthworms (Annelida, Crassiclitellata) from Aragua and Miranda states, Venezuela.

Two new species of the earthworm genus Pontoscolex found in San Casimiro County, northern Venezuela are described. Because of some morphological variability, and to improve the previous description, we redescribe Onychochaeta windlei and Rhinodrilus fuenzalidae collected at La Cortada settlement, Miranda state. Pontoscolex (Mesoscolex) juanae sp. n. and Pontoscolex (Nulloscolex) hugoi subgen. n., sp. n have three pairs of tiny calciferous glands in 7th to 9th segments, with a simple tubular structure similar to that of the genus Onychochaeta; however, testes and funnels are enclosed in sacs in the 11th segment similar to the Pontoscolex. We also report the occurrences of Pontoscolex (Pontoscolex) corethrurus Müller, 1857, Metaphire houlleti (Perrier, 1872), Perionyx excavatus Perrier, 1872, Dichogaster bolaui (Michaelsen, 1891), and Eisenia fetida (Savigny, 1826).

Fast recovery of soil macrofauna in regenerating forests of the Amazon.

The emergence of secondary forests in deforested tropical regions represents an opportunity to mitigate biodiversity loss and climate change, but there is still debate on how fast and to which level these forests can recover biodiversity. Recent studies have shown that the recovery of plant and vertebrate species richness is relatively fast, but the pace of recovery for other groups remains unclear. Soil macroinvertebrates play critical roles on litter decomposition and seed dispersal, therefore the pace of their recovery has consequences for the entire forest ecosystem. We investigated how fast broad taxonomic groups of soil macrofauna recover in the first 30 years of forest regeneration using forests older than 50 years as reference. We surveyed the number, diversity and abundance of 19 broad taxonomic groups of soil macrofauna in 85 sites located in Brazilian Amazon, covering forests of different ages and clearing frequencies. Forest age and clearing frequency were obtained accurately from Landsat images in forests up to 30 years old. We used regression analysis to determine (a) the effects forest age and clearing frequency on macrofauna groups in secondary forests up to 30 years old; and (b) the changes in macrofauna groups between young forests (up to 10 years old), median age forests (between 10 and 30 years old) and forests older than 50 years. We found that the number and diversity of macrofauna groups recover rapidly in the first 10 years of forest regrowth, but show slower change among older forests. This rapid recovery was also observed in the abundance of several taxonomic groups and for predators and detritivores as functional groups. Forest clearing frequency had no effect on the number or the diversity of macrofauna groups, but the abundance of ants increased as forest was cleared more often. Our results for soil macrofauna align with those in plant and vertebrate studies showing that secondary forests quickly recover a large part of their biodiversity and ecological functions. Therefore, global-scale conservation strategies are needed to ensure the opportunity for secondary forests to grow. ​.

A new earthworm species of the genus Rhinodrilus (Rhinodrilidae, Clitellata) and new records of earthworms species from the Amazon-Cerrado-Caatinga transition in the State of Maranhão, Brazil.

We describe a new species of the genus Rhinodrilus from the transition between the Amazon, Cerrado and Caatinga biomes in the State of Maranhão, Brazil. The region is currently being converted to large-scale agriculture, which may cause severe losses in the local fauna and flora diversity yet very poorly studied. Rhinodrilus antonioi sp. nov. has irregular setae in the posterior region of the body, spermathecae without diverticula, tubercula pubertatis in the form of band extended in the line BC in XXI-XXV and clitellum from XIV-XXVII. Five new records are reported for the region, Dichogaster bolaui, Liodrilus mendesi, Pontoscolex (Pontoscolex) corethrurus, Urobenus brasiliensis and Urobenus petrerei.

A new species of Pontoscolex earthworm (Rhinodrilidae, Clitellata) from the Gurupi Biological Reserve, along with records of earthworm species from the Amazon region of Maranhão, Brazil.

We describe a new species of the genus Pontoscolex from the Amazon region of Maranhão State in Brazil. The region is the most deforested and degraded in the biome, with only 25% of the original forest cover left. Pontoscolex awa sp. nov. has regular setae, very small spermathecae, and tubercula pubertatis band-shaped extending to AB line in XIX-XII. Common and genital setae are of similar length and without ornamentations; these features are new in the genus, although unknown in several species. The Gurupi Biological Reserve where the new species was found is the only integral protection area within the Belém Endemism Area and therefore of crucial importance for conservation of earthworms and other endemic organisms.

Benchmark maps of 33 years of secondary forest age for Brazil.

The restoration and reforestation of 12 million hectares of forests by 2030 are amongst the leading mitigation strategies for reducing carbon emissions within the Brazilian Nationally Determined Contribution targets assumed under the Paris Agreement. Understanding the dynamics of forest cover, which steeply decreased between 1985 and 2018 throughout Brazil, is essential for estimating the global carbon balance and quantifying the provision of ecosystem services. To know the long-term increment, extent, and age of secondary forests is crucial; however, these variables are yet poorly quantified. Here we developed a 30-m spatial resolution dataset of the annual increment, extent, and age of secondary forests for Brazil over the 1986-2018 period. Land-use and land-cover maps from MapBiomas Project (Collection 4.1) were used as input data for our algorithm, implemented in the Google Earth Engine platform. This dataset provides critical spatially explicit information for supporting carbon emissions reduction, biodiversity, and restoration policies, enabling environmental science applications, territorial planning, and subsidizing environmental law enforcement.

Author Correction: Benchmark maps of 33 years of secondary forest age for Brazil.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

An overview of the ant fauna (Hymenoptera: Formicidae) of the state of Maranhão, Brazil

The state of Maranhão, located in northeastern Brazil, comprises three biomes: Amazonian, Caatinga, and the Cerrado. To date, 99 ant species have been recorded in the literature from the state. In the present work, we provide for the first time a profile of the ant fauna in the state based on data from the historical literature and Brazilian institutional collections. The updated records on ant diversity for the state of Maranhão revealed a total of 279 species, belonging to 71 genera and 10 subfamilies. In total, 180 species are recorded for the first time in the state, of which four species recorded for the first time in Brazil. In summary, apart from documenting the ant fauna of the region, these results provide a basis for further studies and may contribute to future conservation efforts for the biomes present in this complex landscape.(AU)

¿Refleja Formicidae el impacto de la degradación de los bosques ribereños en la Amazonía Oriental?

La creciente presión antropogénica sobre la Amazonia Oriental hace imperativo el diagnóstico de la degradación forestal y, particularmente, su efecto sobre las comunidades clave dentro de los ecosistemas ribereños, unos de los últimos bosques amazónicos remantes en el estado de Maranhão. La familia de hormigas Formicidae juega un papel fundamental en el suelo, refleja los cambios en el uso de la tierra y es un grupo abundante en los bosques estudiados. Este trabajo tuvo como objetivo determinar el efecto del gradiente sucesional en la riqueza, frecuencia y composición de esta familia. El muestreo fue realizado durante los periodos seco y lluvioso con el método TSBF. Los organismos recolectados se identificaron a nivel de morfoespecies y se crearon curvas de acumulación de especies. Fueron utilizados modelos lineales mixtos para evaluar los efectos del periodo de recolecta local y estado de sucesión en la riqueza y la frecuencia de las hormigas. Por otro lado, se utilizaron regresiones polinómicas para investigar la relación entre la riqueza y la frecuencia de los formícidos según la cobertura del dosel y la altura de la vegetación. La composición de especies fue representada a través del índice de similitud de Jaccard. En total, 1 940 individuos fueron separados en 86 morfoespecies. Se obtuvo más del 80 % de la riqueza de especies probables. La frecuencia y riqueza de hormigas aumentó significativamente siguiendo la sucesión con valores bajos en las áreas abiertas durante la estación seca. Asimismo, durante esta estación, la cobertura del dosel y la altura de la vegetación tuvieron un efecto parcial en la riqueza y frecuencia de Formicidae. Por su parte, las áreas de sucesión intermedia y avanzada presentaron una composición similar con 50 especies compartidas, seguidas de las áreas de sucesión temprana con 43 y el uso antrópico con 34. Concluimos que la eliminación de los bosques ribereños tiene un efecto considerable sobre la riqueza y frecuencia de Formicidae, con valores mínimos en áreas degradadas durante la estación seca. Por otro lado, las áreas de bosques transformadas en sistemas agrícolas sufrieron pérdidas de 41 y 56% en la riqueza y frecuencia respectivamente. Con la sucesión, se restauran la estructura y las funciones del bosque favoreciendo la recolonización de las especies de hormigas. Finalmente, estos himenópteros son un grupo clave en los programas de monitoreo para la conservación/restauración de los bosques ribereños locales.

The increasing anthropogenic pressure on Eastern Amazon makes imperative the diagnosis of forest degradation, particularly the effect on key communities within the riparian ecosystems, one of the last remaining Amazonian forests in Maranhão State. The ant family Formicidae is an abundant group in these types of forests plays a fundamental role on the soil and also reflects the land use changes. Therefore, this study aimed to determine the impact of riparian forest successional stages on the Formicidae richness, frequency, and composition. Sampling was performed during both dry and wet seasons using the TSBF method. Collected organisms were identified as morphospecies. Also, species-accumulation curves were created. Linear mixed models were used to evaluate the effects of seasonal, local, and successional stage on ant richness and frequency. Polynomial regression models were applied to investigate the relationship between ant richness and frequency with canopy cover and vegetation height. Lastly, the species composition was represented by the Jaccard similarity index. In total, we observed 1 940 individuals grouped into 86 morphospecies. We obtained more than 80 % of the probable species richness. Ant frequency and richness increased significantly, following the successional stage, with low values in the open areas, especially during the dry season. Canopy cover and vegetation height seemed to affect partially both Formicidae richness and frequency during the dry season. Intermediate and advanced successional areas presented similar composition (50) shared species, followed by the areas of early succession (43) and anthropic use (34). We concluded that the elimination of riparian forests produces a considerable effect on the richness and frequency of the Formicidae family, minimally affecting them in open areas during the dry season, but resulting in losses of 41 % in richness and 56 % in frequency in forest areas when they are transformed into agricultural systems. Nevertheless, succession restores forest structure and functions, thus favoring re-colonization of ant species. Formicidae reflects forest degradation and is a key group in monitoring programs for the conservation/restoration of local riparian forests.

An overview of the ant fauna (Hymenoptera: Formicidae) of the state of Maranhão, Brazil

The state of Maranhão, located in northeastern Brazil, comprises three biomes: Amazonian, Caatinga, and the Cerrado. To date, 99 ant species have been recorded in the literature from the state. In the present work, we provide for the first time a profile of the ant fauna in the state based on data from the historical literature and Brazilian institutional collections. The updated records on ant diversity for the state of Maranhão revealed a total of 279 species, belonging to 71 genera and 10 subfamilies. In total, 180 species are recorded for the first time in the state, of which four species recorded for the first time in Brazil. In summary, apart from documenting the ant fauna of the region, these results provide a basis for further studies and may contribute to future conservation efforts for the biomes present in this complex landscape.

Efecto de la riqueza de especies y estructura de la vegetación en el almacenamiento de carbono en sistemas agroforestales de la Amazonía, Bolivia / Effect of species richness and vegetation structure on carbon storage in agroforestry systems in the Southern Amazon of Bolivia

Resumen Los sistemas agroforestales diversos concilian la producción de alimentos, la conservación de la biodiversidad y la provisión de servicios ecosistémicos como el secuestro de carbono atmosférico. Sin embargo, el papel de la riqueza florística sobre la producción de carbono en la biomasa de estos sistemas no está claro. Este estudio evaluó el efecto de la riqueza de especies y la estructura de la vegetación sobre el carbono en la biomasa de diferentes sistemas agroforestales, en la Amazonía Sur de Bolivia. Para eso, fueron estudiados 25 sistemas agroforestales y 4 bosques secundarios, en los departamentos de Santa Cruz y Beni. En cada sistema se instalaron parcelas circulares de 1 963 m2, donde la vegetación (árboles, arbustos y herbáceas) y necromasa (hojarasca, ramas y árboles muertos) fueron muestreados. Se utilizó funciones lineales y logarítmicas para evaluar el efecto de la riqueza y estructura de la vegetación sobre el carbono; y la partición de la varianza para examinar el efecto puro y compartido de las variables riqueza y estructura. Las regresiones mostraron una relación positiva fuerte de la riqueza de especies sobre el carbono de la biomasa (r2 = 0.74; P < 0.001). En la partición de la varianza, el 85.7 % de la variabilidad del carbono fue explicada por la riqueza, estructura y variación de la estructura. De forma aislada, la riqueza explicó el 12.7 %, la estructura el 8.8 % y la variación de la estructura el 4.8 %. Estos resultados confirman que el carbono en la biomasa sobre el suelo aumenta con la riqueza de especies y la variación estructural de la vegetación. Por lo tanto, sistemas agroforestales más biodiversos y estratificados son más eficientes en el uso de los recursos y pueden contribuir con la mitigación del cambio climático.(AU)

Abstract Diverse agroforestry systems conciliate food production, biodiversity conservation, and the provision of ecosystem services as atmospheric carbon sequestration. However, the role of floristic richness in the production of biomass in these systems is not clear. This study evaluated the effect of species richness and vegetation structure on aboveground biomass carbon in different agroforestry systems in the Southern Amazon of Bolivia. For that, 25 agroforestry systems and 4 secondary forests were studied in the departments of Santa Cruz and Beni. In each system, a 1 963 m2 circular plot was installed, where the vegetation (trees, shrubs and herbaceous) and necromass (leaf litter, branches and dead trees) were sampled. Linear and logarithmic functions were used to evaluate the effect of vegetation richness and structure on carbon, and the variance partition was used to examine the pure and shared effect of the richness and vegetation structure variables on carbon. Regressions showed a positive strong relationship between species richness and carbon (r2 = 0.74; P < 0.001). The partition of carbon variance showed that richness, structure and variation of the structure explained 85.7 %. Alone the richness explained 12.7 %, the structure 8.8 % and the variation of the structure 4.8 %. These results confirm that carbon in the aboveground biomass increases with species richness and structural variation of the vegetation. Therefore, more biodiverse and stratified agroforestry systems are more efficient in the use of resources and can contribute to climate change mitigation.(AU)

Brasilisia n. gen. and Arraia n. gen., two new genera of Ocnerodrilidae (Annelida, Clitellata, Oligochaeta) from Eastern Amazonia, Brazil.

We describe two new species from two new genera of Ocnerodrilidae from Alcântara and Rosário counties of Maranhão, Brazil. They were collected in very sandy soil in the transition between the Amazonia and Cerrado biomes. One of the species, Brasilisia punki n. sp., is the first report of earthworms of this family with an unusual pattern of genital markings and a gizzard in segment five. The other species Arraia nelmae n. sp. has a gizzard in segment six and a pair of calciferous glands in nine. We also provide an updated key for all genera of Ocnerodrilidae.

Three new species of Holoscolex (Clitellata, Glossoscolecidae) from the Gurupi Biological Reserve, last forest remnant of the Belém Endemism Area, Eastern Amazon.

We describe three new species of the earthworm genus Holoscolex from the Gurupi Biological Reserve in Maranhão state, Brazil. The Reserve, with the Indigenous Territories Awá, Caru, Alto Turiaçu and Alto Rio Guamá represent the last continuous forest remnants of the Belém Endemism Area, the most deforested and threatened area of Brazilian Amazonia. Holoscolex dossantosi sp. nov. has tubercula pubertatis looking like double bands, Holoscolex alatus sp. nov. presents alate tubercula pubertatis, and Holoscolex fernandoi sp. nov. has testis sacs and several intraclitellar atrial glands associated with genital markings between XIX and XXII. The presence of these unusual characters in Holoscolex fernandoi sp. nov. suggests that this species could be an evolutionary transitional stage linking Eudrilidae and more recent Glossoscolecidae genera.

Additions to Andiorrhinus (Turedrilus) (Rhinodrilidae, Clitellata) from Eastern Amazonia.

Two new species of the earthworm family Rhinodrilidae (Clitellata), from Maranhão state, Brazil, were studied by dissection. Andiorrhinus (Turedrilus) miricuri n. sp. is the first record of a big earthworm for this region with three pairs of large spermathecae in segments 7-9 and one pair of tubercula pubertatis bands lateral to b line in XX-XXV. Andiorrhinus (Turedrilus) barrosoi n. sp. lacks spermathecae and has one pair of tubercula pubertatis bands lateral to b line in XX-(1/3) XXIV. The earthworms described are from the most threatened region of Amazonia where 75% of forest cover is already lost. More information is urgently necessary to assess their ecology and vulnerability status.

New earthworm species of Righiodrilus (Clitellata, Glossoscolecidae) from eastern Amazonia.

Three new species of the glossoscolecid earthworm genus Righiodrilus are described from material collected in northern Pará and Maranhão States, Brazil. Rhigiodrilus gurupi n. sp. is characterized by four pairs of post-testicular spermathecae in xiv-xvii. Rhigiodrilus viseuensis n. sp. is distinguished by tubercula pubertatis in xix-xxiii and clitellum in xvi-xxiii. Rhigiodrilus moju n. sp. is the only species in the genus that lacks tubercula pubertatis. We provide an updated key and a distribution map for all species of Righiodrilus.

Taxones superiores de hormigas como sustitutos de la riqueza de especies, en una cronosecuencia de bosques secundarios, bosque primario y sistemas agroforestales en la Amazonía Oriental, Brasil / Ants' higher taxa as surrogates of species richness in a chronosequence of fallows, old-grown forests and agroforestry systems in the Eastern Amazon, Brazil

ResumenLa deforestación es una de las principales causas de pérdida de biodiversidad en todo el mundo. Las hormigas son clave como ingenieras del ecosistema, por lo tanto, la pérdida de la diversidad de hormigas puede indicar la pérdida de funciones cruciales de los ecosistemas. El objetivo de este estudio fue evaluar la riqueza de hormigas del suelo y estimar si los niveles superiores (Subfamilia y Género) pueden ser usados como sustitutos para estimar la riqueza de especies en diferentes estados de sucesión del bosque (bosque primario, bosque secundario y sistema agroforestal) en la Amazonía Oriental. Fueron muestreadas 65 parcelas en el estado de Maranhão y Pará entre 2011 y 2014. El esquema de muestreo siguió el procedimiento de Biología de Suelos Tropicales y Fertilidad (TSBF). Primero caracterizamos los tipos de vegetación de acuerdo con su edad y luego se estimó la riqueza de especies. Para evaluar si los taxones superiores pueden utilizarse como sustitutos utilizamos funciones lineales y exponenciales y correlación de Pearson. En total, se identificaron 180 especies distribuidas en 60 géneros. Los resultados mostraron que la riqueza fue superior en el bosque secundario intermedio (88) y avanzado (76) y fue menor en el sistema agroforestal (38) y bosque ribereño primario (35). El género fue el mejor sustituto para estimar la riqueza de especies de hormigas a través de los diferentes tipos de sucesión vegetal, explicando entre el 72-97 % (P < 0.001) de la variabilidad total de especies. Nuestros resultados confirman que el uso del nivel de género es un excelente sustituto para estimar la riqueza de especies de hormigas en la región y tanto los bosques en regeneración y sistemas agroforestales pueden contribuir en la conservación de la comunidad de hormigas en la Amazonía Oriental.

Abstract:Deforestation in Amazon forests is one of the main causes for biodiversity loss worldwide. Ants are key into the ecosystem because act like engineers; hence, the loss of ants' biodiversity may be a guide to measure the loss of essential functions into the ecosystems. The aim of this study was to evaluate soil ant's richness and to estimate whether higher taxa levels (Subfamily and Genus) can be used as surrogates of species richness in different vegetation types (fallows, old-growth forests and agroforestry systems) in Eastern Amazon. The samples were taken in 65 areas in the Maranhão and Pará States in the period 2011-2014. The sampling scheme followed the procedure of Tropical Soil Biology and Fertility (TSBF). Initially, the vegetation types were characterized according to their age and estimated species richness. Linear and exponential functions were applied to evaluate if higher taxa can be used as surrogates and correlated with the Pearson coefficient. In total, 180 species distributed in 60 genera were identified. The results showed that ant species richness was higher in intermediate fallows (88) and old secondary forest (76), and was lower in agroforestry systems (38) and mature riparian forest (35). The genus level was the best surrogate to estimate the ant's species richness across the different vegetation types, and explained 72-97 % (P < 0.001) of the total species variability. The results confirmed that the genus level is an excellent surrogate to estimate the ant's species richness in the region and that both fallows and agroforestry systems may contribute in the conservation of Eastern Amazon ant community. Rev. Biol. Trop. 65 (1): 279-291. Epub 2017 March 01.

Allometric and temporal scaling of movement characteristics in Galapagos tortoises.

Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One-dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life-history trade-offs. We investigated how the temporal scaling of allometric patterns in movement varies over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour - giant Galapagos tortoises (Chelonoidis spp.) - to test how movement metrics estimated on a monthly basis scaled with body size. We used state-space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log-log regression of the power law to evaluate allometric scaling for these movement metrics and contrasted relationships by species and sex. Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected one-fourth scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates. Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one-dimensional scaling of movement, but also generates valuable insights into the movement ecology of iconic yet poorly understood Galapagos giant tortoises.

Impacto da degradação sobre o estoque total de carbono de florestas ripárias na Amazônia Oriental, Brasil / Impact of degradation on carbon stock of riparian forests in the eastern Amazon, Brazil

Riparian forests provide essential ecosystem services to humanity, but are being degraded at an accelerated rate in the Amazon. This study aimed to quantify carbon stocks above and below ground in riparian forests with four levels of degradation (very high, high, medium and low) in two watersheds (Pepital Rio and Rio Grande) in Alcântara, Eastern Amazon. Twenty-four permanent plots of 1,000 m2 were installed, and vegetation (trees, shrubs, herbs, lianas and palms), necromass (litter, dead trees, branches) and soil (0-20 cm and roots) were sampled. The biomass was estimated using allometric models (vegetation with dbh> 1 cm and dead trees) and destructively (herbaceous, litterfall, branches, roots). The total carbon stock in the most conserved riparian forests ranged between 88 and 202 Mg(C) ha-1. Degradation significantly reduced carbon stock in all compartments (up to 97% in above-ground biomass, up to 91% of necromass, and up to 47% in soils). In conserved areas, the aboveground biomass is the largest compartment of the total carbon stock (> 70%), mainly due to large trees. The carbon stock in the different compartments are strongly correlated with each other and with the canopy opening. The incorporation of these results in regional carbon models can assist in the implementation and review of the Brazilian Forest Act, particularly in the restoration of riparian forests where agriculture is consolidated.(AU)

As florestas ripárias provêem serviços ecossistêmicos essenciais à humanidade, mas estão sendo degradadas em um ritmo acelerado na Amazônia. Esse estudo teve como objetivo quantificar os estoques de carbono acima e abaixo do solo de florestas ripárias com quatro níveis de degradação (muito alta, alta, média e baixa) em duas microbacias (Rio Pepital e Rio Grande) em Alcântara (Maranhão), na Amazônia Oriental. Foram instaladas 24 parcelas permanentes de 1.000 m2, onde a vegetação (árvores, arbustos, herbáceas, lianas e palmeiras), a necromasa (serapilheira, árvores mortas, galhos) e o solo (0-20 cm e raízes) foram amostrados. A biomassa foi estimada mediante modelos alométricos (vegetação com DAP > 1 cm e árvores mortas) e de forma destrutiva (herbáceas, serapilheira, galhos finos, raízes). O estoque total de carbono nas florestas ripárias mais conservadas variou entre 88 e 202 Mg(C) ha-1. A degradação reduziu significativamente o estoque de carbono em todos os compartimentos (até 97% na biomassa viva acima do solo, até 91% de necromassa e até 47% no solo). Nas áreas conservadas, a biomassa viva acima do solo tem a maior participação no estoque total de carbono (> 70%), principalmente devido às árvores de grande porte. O estoque de carbono nos diferentes compartimentos estão fortemente relacionados entre si e também com a abertura do dossel. A incorporação desses resultados em modelos regionais de carbono pode auxiliar na implementação e revisão do Código Florestal Brasileiro, em particular na restauração das florestas ripárias onde a agricultura está consolidada.(AU)