Seed bank and seed rain in a seasonal semi-deciduous forest in south-eastern Brazil

2002 ◽  
Vol 18 (5) ◽  
pp. 759-774 ◽  
Author(s):  
Maria Tereza Grombone-Guaratini ◽  
Ricardo Ribeiro Rodrigues
Keyword(s):  
Seed Bank ◽  
Rainy Season ◽  
Deciduous Forest ◽  
Similarity Index ◽  
Seed Rain ◽  
Seasonal Effects ◽  
South Eastern ◽  
Eastern Brazil ◽  
Annual Total ◽  
Dry Seasons

To examine the influence of seasonality on the abundance and composition of species in the community, we studied the seed rain and the seed bank in a seasonal, semi-deciduous forest in south-eastern Brazil. Soil samples (depth 3 cm, 0.25 m2) were collected within a 1-ha plot in the dry seasons of 1996 and 1997 and the rainy season of 1997 (84 samples per collection). Thirty-five seed traps (0.25 m2 each) were placed randomly in the forest from March 1997 to February 1998. The greatest density of seeds in the soil occurred in samples collected during the rainy season, the period which coincides with the main fruiting period in this forest. The Sørensen similarity index values for the seed bank composition among the three periods were high (> 0.50). The fallout of propagules was strongly seasonal, with more than half of the annual total number of seeds being caught in the two months around the end of the dry season and beginning of the rainy season. The mean density of seeds in the soil bank was nearly 86% lower than the seed rain density. There was no clear evidence of seasonal effects on species density and richness in this forest.

scholarly journals Seed Rain, Soil Seed Bank, and Seedling Emergence Indicate Limited Potential for Self-Recovery in a Highly Disturbed, Tropical, Mixed Deciduous Forest

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1391
Author(s):  
Anussara Chalermsri ◽  
La-aw Ampornpan ◽  
Witoon Purahong
Keyword(s):  
Mortality Rate ◽  
Seed Bank ◽  
Tree Species ◽  
Deciduous Forest ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Seed Rain ◽  
Reproductive Phenology ◽  
Mixed Deciduous Forest ◽  
Standing Vegetation

Human activity negatively affects the sustainability of forest ecosystems globally. Disturbed forests may or may not recover by themselves in a certain period of time. However, it is still unclear as to what parameters can be used to reasonably predict the potential for self-recovery of human-disturbed forests. Here, we combined seed rain, soil seed bank, and seed emergence experiments to evaluate the potential for self-recovery of a highly disturbed, tropical, mixed deciduous forest in northeastern Thailand. Our results show a limited potential for self-recovery of this forest due to low seedling input and storage and an extremely high mortality rate during the drought period. There were 15 tree species of seedlings present during the regeneration period in comparison with a total number of 56 tree species in current standing vegetation. During the dry season, only four tree seedling species survived, and the highest mortality rate reached 83.87%. We also found that the correspondence between the combined number of species and composition of plant communities obtained from seed rain, soil seed bank, and seedling emergence experiments and the standing vegetation was poor. We clearly show the temporal dynamics of the seed rain and seedling communities, which are driven by different plant reproductive phenology and dispersal mechanisms, and drought coupled with mortality. We conclude that this highly disturbed forest needs a management plan and could not recover by itself in a short period of time. We recommend the use of external seed and seedling supplies and the maintenance of soil water content (i.e., shading) during periods of drought in order to help increase seedling abundances and species richness, and to reduce the mortality rate.

scholarly journals Birds of Serra da Capivara National Park, in the “caatinga” of north-eastern Brazil

1993 ◽  
Vol 3 (1) ◽  
pp. 21-36 ◽  
Author(s):  
Fábio Olmos
Keyword(s):  
Threatened Species ◽  
National Park ◽  
Deciduous Forest ◽  
Bird Species ◽  
Buffer Zone ◽  
Habitat Destruction ◽  
South Eastern ◽  
Eastern Brazil ◽  
North Eastern ◽  
Near Threatened

SummarySerra da Capivara National Park covers an area of about 1,300 km2 in south-eastern Piauí, north-eastern Brazil. The park's vegetation is the endemic caatinga, with a few remnants of semi-deciduous forest in some canyons. The area has a reasonable diversity of plants, with 615 catalogued species. Since 1986, 208 bird species have been observed in the park and its buffer zone, including 10 threatened or near-threatened species, plus two recently extinct in the area. Other species are regionally rare and have declined over parts of their distribution. The park also harbours several threatened mammals and caatinga endemics. Despite having been created in 1979 the park remains effectively unprotected and unmanaged. Current levels of poaching and habitat destruction prejudice the future of several species, including some that have already vanished from other parts of the caatinga.O Parque Nacional da Serra da Capivara abrange uma área de aproxidamamente 1,300 km2 no sudeste do Piauí, nordeste do Brasil. A vegetação do parque é a caatinga, com alguns enclaves de mata semi-decíua. A área possui uma razoável diversidade de plantas, com um total de 615 espécies já catalogadas. Desde 1986, um total de 208 espécies de aves foram observadas no parque e sua zona-tampão, incluindo 10 consideradas ameaçadas ou quase-ameaçadas, além de duas recentemente extintas na área. Outras espécies são regionalmente raras ou tern declinado em parte de sua área de distribuição. O parque também abriga diversos mamíferos ameaçados, e endemismos da caatinga. Apesar de ter sido criado em 1979, o parque ainda não foi consolidado e é pouco mais que um parque de papel. Com os presentes niveis de caça clandestina e destruição de habitats, diversas espécies se extinguirão, incluindo algumas já desapareddas de outras partes da caatinga.

Effects of deforestation on seed banks in a tropical deciduous forest of western Mexico

1999 ◽  
Vol 15 (2) ◽  
pp. 179-188 ◽  
Author(s):  
P. M. Miller
Keyword(s):  
Species Composition ◽  
Seed Bank ◽  
Growth Form ◽  
Deciduous Forest ◽  
Similarity Index ◽  
Tropical Deciduous Forest ◽  
Western Mexico ◽  
Pasture Grasses ◽  
One Year ◽  
Germinating Seeds

Seed density and seed bank species composition were determined by germination trials on soils collected during the initial phase of deforestation in a Mexican tropical deciduous forest. The reference forest, pre-burn, 1-d post-burn, and 1-y post-burn soils contained 700, 1000, 70 and 3500 germinating seeds m−2, of 30, 30, 8 and 13 species, respectively. A total of 43 dicotyledonous species were identified. Percentages of herbs, vines, shrubs and small trees/shrubs were similar in reference forest, pre-burn, and 1-d post-burn soils; herbs were the most common growth form. Pasture conversion greatly altered seed bank species composition; 81% of the species that germinated from the seed bank before burning were absent from the seed bank 1 d after the fires. One-year post-burn soil was dominated by monocots; only 3% of the seedlings were herbs; no vines, small trees/shrubs or trees germinated. The reference forest and the pre-burn soils had 18 dicot species in common and the highest similarity index, 0.43; six of the shared species were herbs. One-day and 1-y post-burn soils had the lowest similarity index, 0.05. Burning the slashed forest and conversion to cattle pasture depleted the original seed bank, replacing it by one dominated by pasture grasses.

Reproduction and feeding of the colubrid snake Tomodon dorsatus from south-eastern Brazil

2005 ◽  
Vol 26 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Ivan Sazima ◽  
Otavio Marques ◽  
Alessandra Bizerra
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Rainy Season ◽  
Feeding Behaviour ◽  
South Eastern ◽  
Eastern Brazil ◽  
Body Sizes ◽  
Upper Jaw ◽  
Reproductive Cycles ◽  
Clutch Mass

AbstractBody size, sexual dimorphism, reproductive cycles, fecundity, diet and feeding behaviour of the colubrid snake Tomodon dorsatus from south-eastern Brazil were studied. Females of this viviparous species attained larger body sizes than males, the latter maturing with smaller body size than the former. Vitellogenesis occurred at the onset of rainy season, ovulation by mid rainy season, and parturition from late dry to early rainy season. Reproductive cycle was extended, maybe as a consequence of the low metabolism and food intake. Litter size ranged 4-26 offspring and was correlated with maternal body size. Relative clutch mass ranged 0.48-0.82, and neonates ranged 12-17 cm in snout-vent length. Tomodon dorsatus was shown to feed exclusively on veronicellid slugs quickly swallowed by long excursions of the specialized upper jaw units.

Seasonal responses and genotype-by-season interactions for the growth dynamic and development traits of peanut

2008 ◽  
Vol 146 (3) ◽  
pp. 311-323 ◽  
Author(s):  
N. PHAKAMAS ◽  
A. PATANOTHAI ◽  
K. PANNANGPETCH ◽  
S. JOGLOY ◽  
G. HOOGENBOOM
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Rainy Season ◽  
Growth Traits ◽  
Dry Season ◽  
Seasonal Effects ◽  
Leaf Spot Disease ◽  
Area Index ◽  
Pod Yield ◽  
Dry Seasons

SUMMARYInformation on the interactions between genotypes and environments for physiological traits of peanut (Arachis hypogaea L.) is limited. The objective of the present study was to evaluate the effects of seasons and genotype×season (G×S) interactions for dynamic growth and development traits of peanut. Fifteen peanut lines varying in maturity duration, seed type and yield level were grown in a field experiment at the Khon Kaen University in Northeast Thailand during the 2002 and 2003 rainy seasons and the 2003 and 2004 dry seasons. Data were recorded on phenological development stages, pod yield and final biomass, and leaf area index (LAI), crop growth rate (CGR), pod growth rate (PGR), partitioning coefficient (PC), pod harvest index (HI), shelling percentage, and specific leaf area (SLA) were determined. Seasonal effects were found for all development and growth traits of the test peanut lines. Crop duration for the dry season was much longer than for the rainy season because of low temperatures during the early growth stage, causing a delay in flowering and a longer period of pod formation. The test peanut lines showed small differences in the duration of vegetative development and pod formation, but varied greatly in the seed filling duration. This period also showed the greatest differential responses to seasons between the peanut genotypes. Crop yields for the 2003 rainy and the 2004 dry seasons were much lower than for the other two seasons because of late leaf spot disease in the 2003 rainy season and cool temperatures at flowering in the 2004 dry season, resulting in poor pod setting, low PGR and low HI. The test peanut lines differed considerably in pod and biomass yields and all the growth traits measured. Significant G×S interactions were also found for all of these traits, though were much smaller than season effect. Regression analyses identified PGR as the dominant physiological trait determining the G×S interaction for pod yield. Exploring marker-assisted selection for this trait is suggested.

scholarly journals Effect of season on structural composition of drake testes and daily spermatozoa production as determined by quantitative testicular histology

2016 ◽  
Vol 72 (10) ◽  
pp. 627-631 ◽  
Author(s):  
Godwin Chidozie Okpe ◽  
Anietie Francis Udoumoh
Keyword(s):  
Rainy Season ◽  
Production Efficiency ◽  
Reproductive Potential ◽  
Structural Features ◽  
Dry Season ◽  
Seasonal Effects ◽  
Seminiferous Tubules ◽  
Sperm Production ◽  
Microscopy Technique ◽  
Dry Seasons

Seasonal effects on the structural features of drake testes and daily spermatozoa production were investigated by a light microscopy technique, as well as morphometric and quantitative histological procedures. The present study is aimed at understanding the effects of different seasons on the reproductive potential of drakes. The results showed that the volume of the testes occupied by seminiferous tubules was similar (P>0.05) in all the seasons studied. However, the relative percentage of the primary spermatocytes, spermatids, spermatozoa, epithelial height, lumen diameter, and Leydig cells were significantly higher (p<0.05) during the early and late rainy seasons compared to the early and late dry seasons. The daily sperm production per testis in the early rainy season, late rainy season, early dry season, and late dry season were 0.86 × 109± 1.30, 0.84 × 109± 1.20, 0.54 × 109± 1.13 and 0.52 × 109± 1.17, respectively. The daily sperm productions per testis and per gram of testes were significantly higher (p<0.05) during the early rainy season compared to the early and late dry seasons, respectively. All the micrographs examined, showed evidence of normal spermatogenesis throughout the year. The findings in the present study indicate that drakes in the tropical environment (south-eastern Nigeria) are capable of breeding throughout the year; however, sperm production efficiency is optimal during the early rainy season.

scholarly journals Influence of seasonality on macroinvertebrate diversity associated with the aquatic fern Salvinia biloba Raddi

2020 ◽  
Vol 13 ◽  
pp. e0889
Author(s):  
Rennan Leite Martins Coutinho ◽  
Isabella Rodrigues Lancellotti ◽  
Arthur Ribeiro Flores ◽  
Marcelo Guerra Santos
Keyword(s):  
Water Quality ◽  
Rainy Season ◽  
Heterotrophic Bacteria ◽  
Similarity Index ◽  
Dry Season ◽  
Microbiological Analysis ◽  
Aquatic Fern ◽  
Thermotolerant Coliforms ◽  
Dry Seasons ◽  
Environmental Integrity

Abstract. The genus Salvinia is composed of fast-growing floating ferns, capable of surviving in different environmental conditions. Some authors suggest that the relationships between this genus and macroinvertebrates may serve as water quality indicators. The present study aimed to determine the influence of seasonality and water quality on macroinvertebrate diversity associated with the Salvinia biloba Raddi. Water and fern were collected in rainy and dry seasons and was conducted a microbiological analysis of the water, as well as, the area of fern cover on the water, richness, and density of macroinvertebrates. Microbiological analysis of the water detected > 5,700 CFU/mL (rainy season) and 175 CFU/mL (dry season) of heterotrophic bacteria and was positive for total thermotolerant coliforms. The S. biloba cover on the water surface was 100% in the rainy and 30% in the dry season. In the rainy season, 142 macroinvertebrates were identified, divided into 12 morphospecies, with a density of 434 individuals/m3. In the dry season, there were 419 individuals in 14 morphospecies, with a density of 2,076 individuals/m3 exhibited. The highest species density recorded in the rainy season was for Chironomidae sp.1 (Diptera) (57.71%) and Odonata Zygoptera sp.1 (17.44%), and in the dry season, Chironomidae sp.2 (73.98%) followed by Gerromorpha sp.1 (Hemiptera), with 9.54%. The Sørensen similarity index between the two seasons was 53.84%. The higher density of Gerromorpha sp.1 in the dry season may indicate an increase in environmental integrity. 

scholarly journals Seasonal Differences in Cyclospora cayetanensis Prevalence in Colombian Indigenous People

2021 ◽  
Vol 9 (3) ◽  
pp. 627
Author(s):  
Hagen Frickmann ◽  
Juliane Alker ◽  
Jessica Hansen ◽  
Juan Carlos Dib ◽  
Andrés Aristizabal ◽  
...  
Keyword(s):  
Indigenous People ◽  
Rainy Season ◽  
Gastrointestinal Symptoms ◽  
Dry Season ◽  
Seasonal Effects ◽  
Chain Reaction ◽  
Resource Limited Settings ◽  
Resource Limited ◽  
Stool Samples ◽  
Polymerase Chain

Fecal-orally transmitted cyclosporiasis is frequent in remote resource-limited settings in Central and South America with poor hygiene conditions. In this study, we aimed at assessing seasonal effects on the epidemiology of colonization or infection with C. cayetanensis in Colombian indigenous people living under very restricted conditions. In the rainy season between July and November and in the dry season between January and April, stool samples from indigenous people with and without gastrointestinal symptoms were collected and screened for C. cayetanensis applying in-house real-time polymerase chain reaction (PCR). In the rainy season and in the dry season, positive PCR results were observed for 11.8% (16/136) and 5.1% (15/292), respectively, with cycle threshold (Ct) values of 30.6 (±3.4) and 34.4 (±1.6), respectively. Despite higher parasite loads in the rainy season, fewer individuals (2/16, 12.5%) reported gastrointestinal symptoms compared to the dry season (6/15, 40%). In conclusion, considerable prevalence of C. cayetanensis in Colombian indigenous people persists in the dry season. Low proportions of gastrointestinal symptoms along with higher parasite loads make colonization likely rather than infection.

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