ABSTRACT Background: Seasonally Dry Tropical Forests (SDTF) are recognized by their great biological diversity, but little is known about their temporal patterns, which may be crucial in a changing world. Here we aimed to characterize the SDTF dynamic patterns in floristic and structural changes, and also to evaluate shifts in dynamic rates and structural attributes such as richness, number of trees and biomass. Our hypothesis is that SDTF tree communities have their dynamic characterized by temporal fluctuations related to an instability pattern, in according to the already found for others tropical forests. For this we used a data of 42 400 m² plots in three fragments in the Brazilian Arboreal Caatinga, measured in 2005, 2010 and 2015. We evaluated temporal changes in richness, species composition, trees density, biomass and rates of tree mortality and recruitment; and also rates of biomass gain and loss. Results: We found a pattern of floristic composition stability, but with changes in structure and dynamics. There was a tree density decrease driven by constant mortality and by recruitment decrease, and biomass increase due to decrease in biomass loss and to increase in biomass gain. The biomass increase was main related to a small set of dominant species that are the most representative in the community dynamics. Conclusion: SDTF dynamics are related to stability in species composition, but with structural changes towards higher biomass stocks. The results are main related to community dynamics and to SDTF attributes such as climatic seasonality that drives the local ecological processes.

Abstract The aim of this research was to evaluate the survival and growth of native tree saplings planted in a drained Mauritia flexuosa palm swamp (vereda) in southeastern Brazil, and to identify suitable species for restoration projects in these hygrophilous environments. Total sapling survival at one-year post-planting was 48%. The species with highest sapling survival and growth were Croton urucurana, Cecropia pachystachya, Erythroxylum citrifolium, Hirtella gracilipes and Tapirira guianensis. Lowest survival and growth were found in Mauritia flexuosa, Piper aduncum, Calophyllum brasiliense, Calyptranthes brasiliensis, Myrsine umbellata, Ladenbergia cujabensis and Ficus sp. We indicate the high-survival species for the restoration of these environments. Typical wetland species attained low survival and growth, indicating the negative influence of anthropization on this ecosystem’s resilience, and highlighting the importance of studies investigating suitable strategies to restore them.

SUMMARY: Discrete thresholds of structural or functional decline of a vegetation type are not readily apparent, as a vegetation type can slowly decline leading to transformations in its species composition and weakened or altered functions. However, forest monitoring can be used to assess changes in ecological functions in community structure and functional and phylogenetic composition of species. This study evaluated the existence of temporal variations in the functional and phylogenetic composition of a tree community, the occurrence of heterogeneity in the behavior of phylogenetic and functional variations, and how this possible heterogeneity influences the functional and phylogenetic variations under the aspect of environmental variations and by demographic ecological processes. Results detected quantitative and qualitative changes throughout the community, such as colonization, local extinctions, in demography and biomass, and increased evolutionary distinction, lower wood density species and phylogenetic clustering. These results have shown us that the natural changes of a community should not be underestimated, because the disappearance of a community can not only occur by the direct elimination of vegetation, but can be incremental with gradual changes in its functional characteristics and species composition, transforming itself into a new community with a new combination of species and new functions.

RESUMEN: Los umbrales discretos de deterioro estructural o funcional de un tipo de vegetación no son fácilmente aparentes, ya que un tipo de vegetación puede disminuir lentamente, lo que lleva a transformaciones en la composición de sus especies y funciones debilitadas o alteradas. Sin embargo, las observaciones pueden usarse para evaluar los cambios en las funciones ecológicas antes de que esto ocurra a través de la estructura comunitaria y la composición funcional y filogenética de las especies. Este estudio evaluó la existencia de variaciones temporales en la composición funcional y filogenética de una comunidad arbórea; la ocurrencia de heterogeneidad en el comportamiento de variaciones filogenéticas y funcionales; y cómo esta posible heterogeneidad influye en las variaciones funcionales y filogenéticas bajo el aspecto de variaciones ambientales y por procesos demográficos ecológicos. Los resultados en la detección de cambios cuantitativos y cualitativos en toda la comunidad con la colonización y las extinciones locales en la comunidad, las diferencias demográficas y de biomasa, la distinción evolutiva aumentada, las especies de menor densidad de madera y el agrupamiento filogenético. Los resultados han demostrado que los cambios naturales de una comunidad no deben subestimarse, porque la desaparición de una comunidad no solo puede ocurrir por la eliminación directa de la vegetación, sino que puede ser incremental con cambios graduales en sus características funcionales y composición de especies, transformando en una nueva comunidad con una nueva combinación de especies y nuevas funciones.

Resumo Este estudo analisou as variações florísticas, estruturais e suas relações com variáveis do solo em dois trechos de vegetação ripária em uma região ecotonal entre savana e zonas semi-áridas. Propomos a hipótese de que, apesar da proximidade entre as áreas amostradas, as condições do solo são distintas e levam a mudanças na estrutura e composição da vegetação, mas essas mudanças também são influenciadas pelo caráter ecotonal. Este estudo foi desenvolvido na APA do rio Pandeiros, Minas Gerais, onde alocamos 140 parcelas de 10 ×10 m (100 m2), com 10 m de distância entre parcelas, em duas áreas de vegetação ripária denominadas Larga e São Domingos (70 parcelas em cada área), onde realizamos o levantamento fitossociológico e coletamos amostras de solo. No total, 751 indivíduos arbóreos foram amostrados, distribuídos em 89 espécies e 35 famílias botânicas. As áreas diferiram fortemente na estrutura e composição das espécies, e apresentaram peculiaridades florísticas e influência da vegetação circundante. Apesar da baixa distância entre as áreas amostradas, estes são ambientes singulares influenciados por diferentes solos, pela composição mista da área ecotonal e os impactos antropogênicos a que estão expostas.

Abstract This study analyzed the floristic, structural variations and their relationships with soil variables in two stretches of riparian vegetation in an ecotonal region between savanna and semiarid zones. We following the hypothesis of despite the proximity between the sampled areas, soil conditions are distinct and lead to changes in structure and composition of the vegetation. This study was development at EPA of Pandeiros River, Minas Gerais, where we allocated 140 plots of 10 × 10 m (100 m2), with 10 m distance between plots, in two areas of riparian vegetation, named Larga and São Domingos (70 plots in each area), where we conducted the phytosociological survey and collected soil samples. In total, 751 arboreal individuals were sampled, distributed in 89 species and 35 botanical families. The areas differed strongly in structure and species composition, and showed floristic peculiarities and influence of surrounding vegetation. Despite of low distance between the sampled areas, these are singular environments influenced by different soils, by the mixed composition of the ecotonal area and the anthropogenic impacts to which they are exposed.

ABSTRACT This study monitored the survival of saplings planted according to different recovery models in a riparian forest of the Pandeiros river (Januária, MG). The models consisted of planting the saplings in lines of 2 or 4 m with presence (T2S and T4S, respectively) or absence of direct seeding (T2 and T4, respectively). We planted 16,259 saplings of 17 botanical families, 32 genera and 33 species. The saplings, in general, presented a survival rate after one year of 34.4% (±1.8). The species with highest survival rates were Jacaranda brasiliana, with 85.0% (±13.5) of survival, Anadenanthera colubrina, with 70.1% (±7.0), and Triplaris gardneriana, with 69.3% (±9.1). Survival did not vary between the models tested, probably due to the short evaluation period (12 months).

RESUMO Este trabalho objetivou avaliar o crescimento e sobrevivência de sete espécies arbóreas nativas em diferentes tratamentos, em uma área degradada na Reserva da COPASA (Juramento, MG). Para tal, foram utilizados aproximadamente 1,2 ha da área, onde foram plantadas 899 mudas, de sete espécies nativas (Anadenanthera colubrina, Copaifera langsdorffii, Dilodendron bipinatum, Myracrodruon urundeuva, Pterogyne nitens, Schinopsis brasiliensis e Senegalia polyphylla), acompanhadas durante 24 meses. A área foi dividida em cinco parcelas de 0,24 ha, que representaram os seguintes tratamentos: (T1) parcela semeada com capim (Brachiaria sp.); (T2) parcela onde as covas foram tratadas com condicionador de solo; (T3) parcela semeada com capim consorciado com leguminosa (Cajanus cajan); (T4) parcela semeada com leguminosa; e (T5) controle. A porcentagem de mortalidade foi maior no T2 e menor no T3, sendo as espécies C. langsdorffii (43,66%) e S. brasiliensis (11,64%) aquelas com maior e menor porcentagem de mortalidade, respectivamente. O crescimento (altura e diâmetro) das mudas foi maior no T2 (24,32 ± 26,05 cm e 0,51 ± 0,37 mm, respectivamente) e menor no T1 (10,82 ± 22,57 cm e 0,26 ± 0,27 mm; respectivamente). As espécies com maior crescimento em altura foram A. colubrina e S. polyphylla, já D. bipinatum e S. brasiliensis apresentaram maior crescimento em diâmetro. Pterogyne nitens apresentou o menor crescimento, além de alta mortalidade, mostrando baixa capacidade de estabelecimento em ambientes degradados.

ABSTRACT This study aimed to evaluate the growth and survival of seven native tree species in different treatments in a degraded area at COPASA Reserve (Juramento, MG). Approximately 1.2 ha area was used, where 899 seedlings were planted of seven native species (Anadenanthera colubrina, Copaifera langsdorffii, Dilodendron bipinatum, Miracrodruon urundeuva, Pterogyne nitens, Schinopsis brasiliensis and Senegalia polyphylla) followed for 24 months. The area was divided into five plots of 0.24 ha, which represented the following treatments: (T1) plot sown with grass (Brachiaria sp.); (T2) plot where the pits were treated with soil conditioner; (T3) plot sown with grass and legumes (Cajanus cajan) together; (T4) plot sown with legumes; and (T5) control. The mortality percentage was higher in T2 and lower in T3, and the species C. langsdorffii (43.66%) and S. brasiliensis (11.64%) were the ones with higher and lower mortality rate, respectively. The growth (height and diameter) of seedlings was higher in T2 (24.32 ± 26.05 cm and 0.51 ± 0.37 mm; respectively) and lowest in T1 (10,82 ± 22,57 cm and 0,26 ± 0,27 mm; respectively). The species with the largest growth in height were A. colubrina and S. polyphylla, and D. bipinatum and S. brasiliensis showed the highest growth in diameter. Pterogyne nitens showed the lowest growth, and highest mortality, presenting low ability to establish in degraded environments.