ABSTRACT Climate influences species distribution and selects different morphological traits. The Chaco biome has climatic gradients, leading us to question morphological trait distribution. Using Fabaceae as a study model, we aimed to understand how the dispersal traits of this family, such as fruit types, dispersal syndromes and dispersal units, are distributed along the climatic gradients in the Chaco. We performed a spatial analysis in order to generate spatial predictors and thus identify on which spatial scales climate and soil variables are relevant to the distribution of the traits. Also, we used Threshold indicator rate analysis to identify the variation of the traits along the gradients. Temperature seasonality, precipitation seasonality, and annual mean precipitation are significant predictors of the distribution of the analyzed traits. Anemochory and barochory show the occurrence of reductions in intermediate gradient values for temperature seasonality. Regarding precipitation seasonality, craspedium showed greater reductions. At intermediate values of the rainfall gradient, we observed an increase in the occurrence of drupes and follicles. Craspedium increases in drier regions. Understanding the dispersion patterns of Fabaceae, a group of significant ecological and ethnological relevance in the Chaco, should contribute to the consolidation of conservation plans in different dry forest areas in South America. model family types units Also seasonality follicles regions America

This study verified the differences in richness, density and species composition of the seed bank under the canopy s tree species and the adjacent field area and the relationship of total stem height and crown area to density and richness bank seeds. The seed bank was collected under the canopy of 10 individuals of each species (Curatella americana L., Luetzelburgia auriculata (Allemão) Duckee, Copernicia prunifera (Mill.) H.E.Moore)), and at 10 points in an adjacent field area. The density and richness of the seed bank was larger under the crowns of the species. The total stem height showed a positive relationship with richness and density of the seed bank, and a canopy area negative relationship. The tree species studied enhance the generation of seed bank, increasing its richness and density. They also influence species distribution and local diversity.

Este estudo verificou as diferenças na riqueza, densidade e composição de espécies do banco de sementes sob a copa es espécies arbóreas e a área de campo adjacentes e a relação entre altura total do caule e área da copa com a densidade e riqueza do banco de sementes. Foram coletados o banco de sementes sob a copa de 10 indivíduos de cada espécies (Curatella americana L., Luetzelburgia auriculata (Allemão) Duckee, Copernicia prunifera (Mill.) H.E.Moore)), e em 10 pontos em área de campo adjacente. A densidade e riqueza do banco de sementes foram maiores sob as copas das espécies. A altura do caule apresentou relação positiva com riqueza e densidade do banco de sementes e, área da copa relação negativa. As espécies arbóreas estudadas potencializam a formação de banco de sementes, aumentando a riqueza e densidade. Também influenciam na distribuição das espécies e na diversidade local.

RESUMO Este estudo verificou as diferenças na riqueza, densidade e composição de espécies do banco de sementes sob a copa es espécies arbóreas e a área de campo adjacentes e a relação entre altura total do caule e área da copa com a densidade e riqueza do banco de sementes. Foram coletados o banco de sementes sob a copa de 10 indivíduos de cada espécies (Curatella americana L., Luetzelburgia auriculata (Allemão) Duckee, Copernicia prunifera (Mill.) H.E.Moore)), e em 10 pontos em área de campo adjacente. A densidade e riqueza do banco de sementes foram maiores sob as copas das espécies. A altura do caule apresentou relação positiva com riqueza e densidade do banco de sementes e, área da copa relação negativa. As espécies arbóreas estudadas potencializam a formação de banco de sementes, aumentando a riqueza e densidade. Também influenciam na distribuição das espécies e na diversidade local.

ABSTRACT This study verified the differences in richness, density and species composition of the seed bank under the canopy s tree species and the adjacent field area and the relationship of total stem height and crown area to density and richness bank seeds. The seed bank was collected under the canopy of 10 individuals of each species (Curatella americana L., Luetzelburgia auriculata (Allemão) Duckee, Copernicia prunifera (Mill.) H.E.Moore)), and at 10 points in an adjacent field area. The density and richness of the seed bank was larger under the crowns of the species. The total stem height showed a positive relationship with richness and density of the seed bank, and a canopy area negative relationship. The tree species studied enhance the generation of seed bank, increasing its richness and density. They also influence species distribution and local diversity.

Resumo Espécies vegetais sujeitas a Inundação e fogo podem manifestar estratégias de sobrevivência como o banco de sementes do solo. Pretendemos determinar a influência de fogo e inundação na riqueza, abundância e diversidade do banco de sementes. Realizamos amostragens em um ano mais seco (outubro/2013) e em um de maior inundação (outubro/2014), em dez áreas ao longo do rio Paraguai. Selecionamos 5 áreas com históricos de fogo antigo (2010, 4 anos antes da amostragem) e 5 recente (2013, 1 ano antes da amostragem). Nas áreas, marcamos transectos de 20 m, nos quais coletamos 10 amostras de solo (20 × 20 × 5 cm), cinco com e cinco sem serrapilheira. Composição e abundância do banco de sementes foram estimadas por meio de emergência de plântulas. Áreas de fogo antigo apresentaram maior abundância que áreas de fogo recente. O ano de seca apresentou maiores abundância e riqueza do que o de inundação. A remoção da serrapilheira reduziu a riqueza no ano de inundação. Não houve diferença em riqueza no ano seco. A abundância nas amostras com e sem serrapilheira foram similares. A interação entre fogo e inundação não afetou a abundancia, riqueza e diversidade do banco de sementes.

Abstract Flood and fire can harm plants but they can have survival strategies, such as the seed bank. We aimed to determine the influence of fire and flood on the richness, abundance and diversity of the seed bank. Sampling was carried out in October/2013, year of prolonged drought, and October/2014, year of a heavy flood, in ten areas along the Paraguay River. The areas were selected in satellite images, five with old burn (2010, three years before sampling) and five with recent burn (2013, three months before sampling). In each area, we marked a 20 m long transect with ten 20 × 20 cm quadrats where we collected 5 cm deep topsoil samples, five with and five without litter. Seed bank richness and abundance were determined by seedling emergence. Old burn areas presented greater abundance than recent burn. The drier year presented greater abundance, richness and diversity than flood year. Removal of litter reduced the richness only in the wetter year. There was no difference in richness in the drier year. The removal of the litter did not affect the abundance and diversity. Interaction between fire and flood did not affect richness, abundance and diversity of the seed bank.

ABSTRACT Evaluation of the effects of flooding on seedling recruitment from seed banks helps in understanding vegetation regeneration in floodplains. We studied the effects of simulated flooding on richness and abundance of, and temporal variation in, seedling recruitment from the soil seed bank of a floodable savanna of the Pantanal wetland, under two conditions: 1) Post-flood = inundated for 30 days followed by irrigation; 2) Non-flooded = only irrigated. We recorded emerged seedlings biweekly for 120 days and found a total of 124 species for the two treatments, the most abundant species were annual herbs (e.g., Richardia grandiflora and Euploca procumbens) and annual graminoids (e.g., Digitaria ciliaris and Cyperus haspan). Flooding positively influenced seedling richness and abundance, while seedling emergence from the non-flooded soil was slower, but continued during all periods. The different temporal patterns between treatments showed that flooding increases the abundance of emerged seedlings and acts as a trigger for explosive recruitment shortly after water depletion.