ABSTRACT Background. In 1985, as part of a global project within the “Secretaría de Marina” and continued in the “Facultad de Ciencias, Universidad Nacional Autónoma de México” and in “Estudio y Conservación de la Naturaleza, A. C.”, a collection series of stomatopods and decapods crustaceans that inhabit the coral reefs of the East coast of Mexico began. Objective. Provide an updated inventory and analysis of species richness on 12 reefs for the two orders of crustaceans. Method. Manual collection, dredges, free and autonomous diving. Review of national and international collections and bibliographic records. Results. The 12 coral reefs studied are geographically distributed in four groups: northern Veracruz (97 species), central Veracruz (194 species), Campeche (130 species), and Yucatán (196 species). Twelve species, six genera, and five families are recognized for the stomatopods, and 314 species, 155 genera, and 55 families for the decapods. The family with the highest richness was the Alpheidae, with 53 species (due to the plasticity of occupying various available habitats in the reefs and by establishing symbiosis with other taxa), followed by Palaemonidae shrimps (29 species) and the spider crabs of the Mithracidae family (18 species). The Portunidae family (swimming crabs) presented 16 species, followed by porcelain crabs (15 species) and xanthoidean crabs (13 species). Twenty families presented only one species. Some species are considered “species in transit” such as Latreutes fucorum, Latreutes parvulus, and Portunus sayi, which were found to be associated with Sargassum spp. Conclusions. There is no doubt that the inventory of species of the Mexican reefs of the East coast will increase considerably by making a greater sampling effort at different tide phases and times of the year and sampling in specific habitats for certain species.

RESUMEN Antecedentes. En 1985, dentro de un proyecto global de la Secretaría de Marina y continuado en la Facultad de Ciencias de la Universidad Nacional Autónoma de México y en Estudio y Conservación de la Naturaleza, A. C., se inició una serie de recolectas de los crustáceos estomatópodos y decápodos que habitan en los arrecifes de coral de la costa este de México. Objetivo. Proveer un inventario actualizado y análisis de la riqueza de especies en 12 arrecifes para los dos órdenes de crustáceos. Métodos. Recolectas manuales, dragas, buceo libre y autónomo. Revisión de colecciones nacionales e internacionales y registros bibliográficos. Resultados. Los 12 arrecifes de coral estudiados están geográficamente distribuidos en cuatro grupos: Veracruz norte (97 especies), Veracruz centro (194 especies), Campeche (130 especies) y Yucatán (196 especies). Se reconocieron 12 especies, seis géneros y cinco familias para los estomatópodos y 314 especies, 155 géneros y 55 familias para los decápodos. La familia con la mayor riqueza fue Alpheidae con 53 especies (debido a la plasticidad de ocupar diversos hábitats disponibles en los arrecifes y al establecer simbiosis con otros taxones), seguido por los camarones Palaemonidae (29 especies) y los cangrejos araña de la familia Mithracidae (18 especies). La familia Portunidae (jaibas) presentó 16 especies, seguido de los cangrejos porcelánidos (15 especies) y los cangrejos xanthoideos (13 especies). Veinte familias presentaron solo una especie. Algunas especies son consideradas “especies en tránsito” como Latreutes fucorum, Latreutes parvulus y Portunus sayi, las cuales se encontraron asociadas a Sargassum spp. Conclusiones. Indudablemente el inventario de especies de los arrecifes coralinos mexicanos de la costa este, aumentará al efectuar un mayor esfuerzo de muestreo en diferentes fases de marea y épocas del año; así como, muestreos en los hábitats específicos para determinadas especies.

Abstract The presence of a long-wavelength sensitive (LWS) opsin gene was demonstrated in the stygobitic crustacean Creaseria morleyi (Creaser, 1936) by PCR readings from genomic DNA. In order to find the expression of this gene in extraocular tissue, shrimps were collected and placed in a tank to expose them to light/dark conditions for a period of 72 hours, and immediately after, sacrificed and sampled for RNA in the eyes, cephalothorax, abdomen, and sixth abdominal segment plus uropods. The transcripts of the LWS opsin gene were found in the eyes and abdomen of individuals exposed to light. The expression of these opsins could be involved in extravisual functions such as synchronization of their biological processes with environmental cycles related to diurnal vertical migration.

Resumen La anémona Condylactis gigantea es un miembro ecológicamente importante de la comunidad bentónica en arrecifes de coral del Atlántico tropical, y exhibe dos morfotipos con respecto al color de las puntas de sus tentáculos: el morfotipo de puntas verdes y el morfotipo de puntas rosadas/púrpuras. Aunque se han encontrado algunas diferencias moleculares y ecológicas entre estos morfotipos, no se han reportado otras distinciones morfológicas, y actualmente ambos siguen siendo considerados una sola especie taxonómica. En el presente estudio, realizamos una exploración sobre la variabilidad en el tamaño de los cnidocistos entre estos dos morfotipos y realizamos un análisis estadístico de 10 categorías de cnidocistos a partir de especímenes albergados en la Colección de cnidarios del Golfo de México y Caribe Mexicano, de la Universidad Nacional Autónoma de México, los cuales fueron previamente recolectados en varias localidades arrecifales de la Península de Yucatán. Los resultados no revelan variación significativa en el tamaño de los cnidocistos entre los dos morfotipos, aunque fueron encontradas variaciones significativas dentro de cada morfotipo. Adicionalmente, actualizamos la composición del cnidoma de C. gigantea, y discutimos sobre la utilidad de la talla de los cnidocistos para distinguir entre morfotipos o entre especies estrechamente relacionadas.

Abstract The sea anemone Condylactis gigantea is an ecologically important member of the benthic community in coral reefs of the tropical Atlantic, and displays two morphotypes with respect to the color in their tentacular tips: the green tip morphotype and the pink/purple tip morphotype. Although some molecular and ecological differences have been found between these morphotypes, no other morphological distinctions have been reported, and currently both are still considered a single taxonomic species. In the present study, we perform an exploration on the variability in the size of cnidae between these two morphotypes and performed statistical analyses to compare the 10 categories of cnidae from specimens hosted in the Cnidarian Collection of Gulf of Mexico and Mexican Caribbean, of the Universidad Nacional Autónoma de México, which were previously collected in several coral reefs localities of the Yucatán Peninsula. Results reveal no significant variation in cnidae size between the two morphotypes, but significant variations were found within each morphotype. In addition, we update the composition of the cnidom of C. gigantea, and the utility of the size of cnidae to distinguish between morphotypes or closely related species is discussed. Rev. Biol. Trop. 66(3): 1055-1064. Epub 2018 September 01.

A Sinovite Vilonodular Pigmentada é um distúrbio proliferativo raro da membrana sinovial, que afeta adultos jovens e de meia-idade e é geralmente monoarticular. Esta condição pode ser localmente destrutiva e envolver músculos, tendões, bursas, ossos e pele. Os locais mais comuns são o joelho e anca. A incidência no tornozelo é de 2 a 10%. Os pacientes apresentam-se frequentemente com dor, derrame articular e edema. A radiografia simples pode mostrar defeitos no osso adjacente, quistos ósseos e uma borda esclerótica. Derrames podem aparecer como densidades em radiografias e tomografia computadorizada por causa de alto teor de ferro. A ressonância magnética é útil para delinear a extensão dos tecidos moles e envolvimento ósseo. Este caso clínico apresenta uma doente com episódios de hemartrose recorrente do tornozelo a quem foi diagnosticada Sinovite Vilonodular Pigmentada localizada com destruição da cartilagem articular, tratada artroscopicamente com excisão da lesão e furagens de Pridie do astrágalo. A Sinovite Vilonodular Pigmentada localizada tem um excelente prognóstico e um baixo índice de recidiva quando tratada cirurgicamente. O tratamento artroscópico pode ser considerado uma alternativa nestes doentes, uma vez que se trata de um procedimento menos invasivo que oferece a possibilidade de excisão completa.

Pigmented Villonodular Synovitis is a rare proliferative disorder of synovial membrane, which affects young and middle-aged adults and is usually monoarticular. This condition can be locally destructive and involve muscles, tendons, bursae, bones and skin. The most common sites of presentation are the knee and hip. The incidence of Pigmented Villonodular Synovitis ankle is between 2 to 10%. The patients often present with pain, swelling and joint effusion. Plain radiographs may show defects in adjacent bone, bone cysts and a sclerotic rim. Articular effusions may appear as densities on radiographs and computed tomography because of high iron content. Magnetic resonance imaging is useful for delineating the extent of soft tissue and bone involvement. This is a case of a patient with recurrent hemarthrosis of the ankle diagnosed with localized Pigmented Villonodular Synovitis and chondral destruction treated with arthroscopic excision of the lesion and microfractures of the talus. The localized form of Pigmented Villonodular Synovitis has an excellent prognosis and a low recurrence rate when treated surgically. Arthroscopic treatment should be considered in these patients, since it is a less invasive procedure that offers the possibility of complete excision.

Abstract: Parasitic isopods, particularly members of the Bopyridae that infest crustacean hosts, have received scant study in many geographic regions. As part of a project aimed at documenting parasites of fish and invertebrates from the coast of Yucatán, Mexico, 2,467 individuals of the fiddler crab Uca spinicarpa were collected from March 2002 to July 2007. Based on the sampled specimens, we report the presence of Leidya distorta in the branchial chamber of U. spinicarpa for the first time. We found a prevalence of 3.77%, mean intensity of 1.47, and mean abundance of 0.06 for this parasite. With the addition of L. distorta, the number of bopyrids reported from Mexican coasts increases to 44 species. Males of U. spinicarpa were more often infested than females, which could be due to the sex ratio being strongly skewed towards males in the host sample studied (0.85:0.15 M:F). Morphological differences between males and juveniles, as well as between sub-adult and adult females of L. distorta are described.

Resumen: Los isópodos parásitos, particularmente los Bopyridae que infestan crustáceos, han recibido escasa atención en varias regiones geográficas. Como parte de un programa para documentar parásitos de peces e invertebrados en las costas de Yucatán, México, se recolectaron manualmente 2,467 cangrejos Uca spinicarpa de marzo de 2002 a julio de 2007. Como parte de los resultados, reportamos por primera vez la presencia de Leidya distorta en la cámara branquial de U. spinicarpa. También se presentan los valores de prevalencia (3.77%), intensidad media (1.47) y abundancia media (0.06) para este parásito. Con la adición de L. distorta, el número de bopíridos registrados para las costas mexicanas se incrementa a 44 especies. Los machos de U. spinicarpa resultaron más infestados que las hembras, lo que puede estar asociado a la proporción sexual sesgada a favor de los machos de la población hospedera (0.85:0.15 M:H). Se describen algunas variaciones morfológicas de machos y hembras jóvenes, subadultas y adultas de L. distorta.

RESUMO: As inundações urbanas estão se tornando cada vez mais frequentes, de tal forma que a União Europeia publicou a Diretiva 2007/60/CE no sentido de mitigar as consequências relacionadas com este fenômeno e de impor limites à concentração de poluentes nas águas pluviais. O objetivo deste artigo foi apresentar uma modelação dos sistemas de drenagem em situação de inundações, baseada no software da United States Environmental Protection Agency (EPA), Storm Water Management Model (SWMM), em que o estudo de caso é analisar um sistema de drenagem urbana unitário, inserido na Zona Central de Coimbra, em Portugal. Recorrendo à metodologia Automatic Overland Flow Delineation (AOFD) para a geração de uma rede de drenagem superficial e implementando-a no SWMM, obteve-se um modelo de drenagem dual, que permite a análise do escoamento em situação de inundações, incluindo o controle de escoamento entre a superfície e a rede de coletores e a modelação da qualidade da água à superfície. Este modelo permite quantificar a carga poluente à superfície, relativamente ao parâmetro de sólidos suspensos totais, para um evento de precipitação extrema.

ABSTRACT: Urban floods are becoming more frequent. Thus, the European Union published the Directive 2007/60/CE to mitigate costs related with this phenomenon and to impose limits on the concentration of pollutants in pluvial water. The purpose of this study was to present the modelling of drainage systems in flood situations, based on the software of the United States Environmental Protection Agency (EPA), the Storm Water Management Model (SWMM), in which the study case is to analyze a unitary urban drainage system of Zona Central catchment in Coimbra, Portugal. By using the Automatic Overland Flow Delineation (AOFD) methodology for the generation of a superficial drainage network and implementing it in the SWMM, it was obtained a dual drainage model that allows the flow analysis in flood conditions, including flow control between the surface and collectors network and also modeling of water quality at the surface. This model allows quantifying the pollution load at the surface, relatively to the parameter of total suspended solids, for any extreme rainfall event.

The northern coast of the Mexican state of Yucatán has only been cursorily sampled in the past, with most of this effort concentrated on the largest coral reef in the Gulf of México, Arrecife Alacranes. The present study reports on recent collections (June 2008 - September 2013) of caridean shrimp in Yucatán, including Arrecife Alacranes and other reefs, as well as coastal lagoons and beaches. Additionally, a number of species are reported based on older, unidentified museum material. Six species represent new records for the Gulf of México [Janicea antiguensis (Chace, 1972), Gnathophyllum modestum Hay, 1917, Lysmata jundalini Rhyne, Calado and dos Santos, 2012, Periclimenes sandyi De Grave, 2009, Rapipontonia platalea (Holthuis, 1951a), Typton tortugae, McClendon, 1911], and 11 species are confirmed new records for México [Lysmata ankeri Rhyne and Lin, 2006, L. pederseni Rhyne and Lin, 2006, L. rafa Rhyne and Anker, 2007, Ascidonia miserabilis (Holthuis, 1951b), A. quasipusilla (Chace, 1972), Neopontonides chacei Heard, 1986, Periclimenaeus maxillulidens (Schmitt, 1936), P. pearsei (Schmitt, 1932), P. schmitti Holthuis, 1951b, Typton prionurus Holthuis, 1951b, Processa manningi De Grave and Felder, 2012], adding up to a total of 17 newly reported species for the East coast of México. Further, the colour pattern of several species is documented for the first time.

Tropical coral reefs are known to exhibit high levels of biodiversity. Amphipod crustaceans are successfully adapted to a wide range of marine habitats in coral reefs, but some regions, such as the Campeche Bank in southern Gulf of Mexico, are poorly studied or even unsurveyed for amphipods. To begin to address this paucity of information, the present study records amphipod species from Isla Pérez, an island of the Alacranes Reef National Park, southern Gulf of Mexico. Twenty sites were sampled in the intertidal zone and shallow water adjacent to the island. Thirty-one species of amphipod were identified, 15 of which represented a geographical range extension to the northern Yucatan Peninsula, with four new records for the Mexican south-east sector of the Gulf of Mexico; nine for the Gulf Coast of Mexico; and two for the entire Gulf of Mexico. Significantly, a difference in faunal composition between windward and leeward areas of the intertidal zone was found.

Two specimens of Ophioderma ensiferum Hendler and Miller, 1984 were collected at 2 different localities in the Yucatán Peninsula, Mexico. The first one collected at Alacranes Reef, Yucatán, a transition zone between the Gulf of Mexico and the Caribbean, and the second one in an anchialine cave located in Cozumel Island, Quintana Roo. These records expand the known distribution of the species to the southern part of the continental shelf of the Gulf of Mexico. This finding represents the first record of this ophiuroid on the continental shelf of Mexico, and also the first record of this species in an anchialine cave.

Dos especímenes de Ophioderma ensiferum Hendler y Miller, 1984 fueron recolectados en 2 localidades diferentes de la península de Yucatán, México. La primera fue en el arrecife Alacranes, Yucatán, la cual es un área de transición entre el golfo de México y el Caribe, y la segunda en una cueva anquihalina ubicada en la isla de Cozumel, Quintana Roo. Estos registros amplían la extensión de la distribución de la especie hacia el sureste de la plataforma continental del golfo de México. Se presenta el primer registro de dicho ofiuroideo en la plataforma continental de México y el primer reporte de dicha especie en una cueva anquihalina.

The calico box crab Hepatus epheliticus is an abundant species from shallow and continental shelf waters of the Atlantic coast of USA and Mexico. Information about population structure and sexual maturity is absent, even though this crab is caught to be used as bait for the octopus fishery in the Campeche Bank, Mexico. In order to achieve such information, a total of 768 individuals were collected from January to March 2010 through baited traps installed in the Yucatan Peninsula, Mexico. Our results showed that sex ratio is biased towards more males than females (1:0.55), contradicting to that reported in other brachyuran crabs. The absence of ovigerous females suggests that they did not enter into the traps during embryogenesis. Males reached a larger maximum size than females (64.0 ± 6.15 and 58.4 ± 5.60 mm carapace width, respectively). The general scheme of growth being positive allometric throughout ontogeny of both sexes. Males presented a transition phase from juveniles to adult corresponding to the puberty moult. The estimation of the onset of functional sexual maturity revealed a steady situation for the population, with 21.5 and 13.8% of males and females, respectively, morphologically immature at the time of catch. This study constitutes the first report on population structure and sexual maturity in a population of the calico box crab H. epheliticus.

El cangrejo caja moteado Hepatus epheliticus es un abundante braquiuro perteneciente a la familia Hepatidae, distribuido desde aguas someras hasta la plataforma continental en la costa atlántica de Estados Unidos y México. La información sobre su demografía poblacional y madurez sexual es actualmente inexistente, aun cuando esta especie es intensamente capturada como carnada en la pesquería del pulpo del estado de Campeche, México. Entre enero y marzo de 2010, se colectaron 768 especímenes usando trampas instaladas en la Península de Yucatán, México. Los resultados mostraron una proporción sexual completamente inclinada hacia los machos (1:0,55), lo cual contradice el esquema general reportado en otras especies de braquiuros. La ausencia total de hembras ovígeras, sugiere su resistencia a ingresar a las trampas durante el periodo de incubación de los embriones. Los machos alcanzaron un tamaño promedio mayor que las hembras (64,0 ± 6,15 y 58,4 ± 5,60 mm de ancho del caparazón, respectivamente), siendo el crecimiento de tipo alométrico positivo a lo largo de la ontogenia de ambos sexos. Los machos presentaron una fase de transición desde juveniles a adultos correspondiente a la muda de pubertad. La estimación de la madurez sexual funcional mostró una situación normal para la población, con 21,5 y 13,8% de machos y hembras respectivamente, morfológicamente inmaduros al momento de ser capturados. Este estudio constituye la primera aproximación a la estructura poblacional y madurez sexual del cangrejo caja moteado H. epheliticus.

Parâmetros químicos, físicos e biológicos do solo (MO, N total, pH, P2O5, K2O, Mg, B, CR, e as propriedades da microflora fixadora de azoto de vida livre e dos rizóbios) e a produção de pastagens foram caracterizados e utilizados para determinar as relações em 40 locais abrangendo diferentes condições de crescimento dentro do ecossistema "montado". As amostras de solo foram colhidas na Primavera. Uma razoável fertilidade dos solos foi encontrada; apresentando em geral valores intermédios para a MO, K2O, Mg e Bo e valores baixos para o pH e P2O5. As populações de bactérias fixadoras de azoto, de vida livre, foram elevadas, com uma média de 4.2 x 10(7) UFC g-1 de solo, com uma actividade da nitrogenase altamente variável e com uma média de 34 nmoles de C2H4 g-1 de solo h-1. A população rizobiana associada ao Trifolium subterraneum foi elevada, com uma média de 10(6) bactérias por grama de solo, tendo um potencial de fixação de azoto adequado para a maioria dos solos. A população rizobiana associada à Medicago polymorpha foi baixa, com uma média de 6.5 x 10(4) bactérias por grama de solo, um valor insuficiente para uma boa nodulação (no Outono), com um baixo potencial fixador de azoto para a maioria dos solos. A produtividade anual das pastagens naturais variou muito entre os locais, com uma média de 3245 kg ha-1, um valor normal para este ecossistema. Em geral, as propriedades do solo foram independentes das amostras de solo. Os parâmetros químicos MO, P2O5, K2O e N total foram factores importantes para a produção das pastagens. Uma grande variabilidade nas amostras de solo colhidas a uma curta distância foi observada. Uma relação entre a origem geológica e a produtividade foi também verificada, sendo os solos graníticos mais produtivos para as plantas não-leguminosas.

Paramètreschimiques, physiques et biologiques des sols (MO, N total, pH, P2O5, K2O, Mg, B et propriétés de la microflore des microorganismes fixateurs de azote, vivant en vie libre, des Rhizobium) et la production des pâturages ont été caractérisés et utilisés pour déterminer les relations des 40 situations couvrant différentes conditions de croissance parmi l'écosystème "montado". Les terres ont été récoltées et analysées au Printemps. La fertilité des sols a été raisonnable, présentant en général, des valeurs intermédiaires pour la MO, K2O, Mg, et Bo et des valeurs faibles pour pH et P2O5. Les populations de bactéries fixatrices de azote, non symbiotiques, ont été élevées, avec une moyenne de 4.2 x 10(7) de colonies g-1 de sol, la nitrogénase était très variable, avec une moyenne de 34 nmoles de C2H4 g-1 de sol h-1. La population des rhizobia associés au Trifolium subterraneum était élevée, avec une moyenne de 10(6) bactéries g-1 de sol, ayant un potentiel adéquat de fixation d'azote pour la majorité des sols. La population des rhizobia associés à Medicago polymorpha était faible avec une moyenne de 6.5 x 10(4) bactéries g-1 de sol, une valeur insuffisante (à l'Automne) pour une bonne nodulation, ayant un faible potentiel de fixation pour la majorité des sols. La production annuelle des pâturages naturels a varié beaucoup selon les situations, avec une moyenne de 3245 kg ha-1, une valeur normale pour cet écosystème. En général, les propriétés du sol sont indépendantes des situations. Les paramètres chimiques MO, P2O5, K2O et N total ont été des facteurs importants pour la production des pâturages. Une grande variabilité, même dans les situations de sols prélevés à une courte distance, a été observée. Une relation entre l'origine géologique et la productivité a été trouvée, les sols granitiques étant plus productifs pour les plantes non-légumineuses.

Chemical, physical and biological soil parameters (OM, total N, pH, P2O5, K2O, Mg, B, WHC, free-living nitrogen fixing and rhizobial microflora properties) and pastures yield were characterized and used to determine relationships in 40 locations covering different growth conditions of the "montado" ecosystem. Soil samples were collected in Spring. Reasonable soil fertility was found. The soils presented, in general, intermediate values for OM, K2O, Mg, and Bo and low values for pH and P2O5. Populations of free-living nitrogen fixing bacteria were high, with an average of 4.2 x 10(7) CFU g-1 of soil, being nitrogenase activity highly variable, with an average of 34 nmoles of C2H4 g-1 of soil h-1. Rhizobial population associated to Trifolium subterraneum was high, with an average of 10(6) bacteria g-1 of soil, having adequate nitrogen fixing potential for the majority of the soils. Rhizobial population associated to Medicago polymorpha was low, with an average of 6.5 x 10(4) bacteria g-1 of soil, an insufficient value for a good nodulation, having low nitrogen fixing potential for the majority of the soils. Annual yield of natural pastures varied highly among locals, with an average of 3245 kg ha-1, a usual value for this ecosystem. In general, soil properties were independent of the soil samples. The chemical parameters OM, P2O5, K2O and total N were important factors to pasture yield. A great variability, even in soil samples collected within a short distance, was observed. A relationship between geological origin and productivity was found, being the granitic soils more productive in non-legume plants.

Uma das soluções para combater a erosão do solo é a reflorestação. No entanto, as sementeiras efectuadas em terrenos com declives elevados podem deparar-se com o problema de arrastamento das sementes pelo escoamento superficial. Neste trabalho apresentam-se resultados laboratoriais relativos ao estudo do movimento de sementes de Pinus pinea, Pinus pinaster e Grevillea sp., sobre solo nu, utilizando um simulador de chuva e um canal de terra. Para uma dada chuvada, com intensidade constante no tempo, mediram-se os deslocamentos das sementes para declives do canal de 10, 20 e 30%. Os resultados mostram uma estreita relação entre a distância percorrida pelas sementes e características físicas das sementes estudadas (e.g. peso da semente), bem como entre essa distância e o declive do solo.

Le reboisement joue un rôle important de protection du sol contre l'érosion. Toutefois, les semences situées en terrain accidenté peuvent être transportées par les eaux de ruissellement de surface. Cet article scientifique présente des résultats expérimentaux sur le déplacement des semences de Pinus pinea, Pinus pinaster et Grevillea sp. sur un sol nu sous l'action combiné de la pluie et du ruissellement. Le montage expérimental est formé d'un plan rectangulaire recouvert de sol et d'un simulateur de pluie. Des pentes de terrain de 10, 20 et 30% ont été étudiées pour des épisodes de pluie d'intensité constante et de durée fixe. Les résultats montrent une dépendance de la distance de déplacement des semences à leurs caractéristiques physiques (ex. poids) et une autre à la pente.

Reforestation plays an important role against soil erosion. However, seeds on sloping terrains can be displaced downslope by overland flow. This work presents a laboratory study on the movement of seeds of Pinus pinea, Pinus pinaster and Grevillea sp. over bare soil, caused by the combined action of simulated rainfall and drainage channel. The laboratory set-up used a rectangular soil flume and a rainfall simulator. The slope of the flume was set at 10, 20 and 30%. The rainfall events had a constant intensity and a fixed duration. Results show a relation between the seeds displacement distance and the physical characteristics of the seeds (e.g. weight of the seeds) and between that displacement and the slope.