Ecological Characteristics That Enhance Broussonetia papyrifera’s Invasion in a Semideciduous Forest in Ghana

Broussonetia papyrifera (L.) Vent. (Moraceae) was introduced to Ghana in 1969 and has since become second only to Chromolaena odorata as an invasive species in Ghanaian forests. This study determined its ecological traits that enhance its invasion of plant communities. Fruiting and viability patterns were studied through monthly monitoring of 985 trees (≥6 cm gbh) in one forest site. The effect of light on its seed germination was tested in light-proof boxes. Means of propagation were determined by tracking the origin of newly regenerated plants on a newly cleared plot of land that B. papyrifera had occupied. It fruited twice a year with one season (January–March) producing more fruits than the other (July-August). Fruiting occurred in trees as small as 9 cm gbh but the percentage of individuals fruiting in each size class increased with tree size. There was a clear pattern of seed viability during the January–March fruiting period. The species did not appear to have a naturally high seed viability with germination always below 50% of each weekly collection. Seed germination was depressed in dark. These results suggest that the species may be competitive in disturbed forest sites and therefore its spread may be aided by forest degradation.

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The composition and diversity of natural regeneration of tree species in gaps under different intensities of forest disturbance

Journal of Forestry Research ◽

10.1007/s11676-020-01269-6 ◽

2021 ◽

Author(s):

Maame Esi Hammond ◽

Radek Pokorný ◽

Daniel Okae-Anti ◽

Augustine Gyedu ◽

Irene Otwuwa Obeng

Keyword(s):

Tree Species ◽

Natural Regeneration ◽

Forest Disturbance ◽

Forest Site ◽

Gap Formation ◽

Tree Species Composition ◽

Forest Sites ◽

Significant Difference ◽

Shade Tolerant Species ◽

Disturbed Forest

AbstractThe positive ecological interaction between gap formation and natural regeneration has been examined but little research has been carried out on the effects of gaps on natural regeneration in forests under different intensities of disturbance. This study evaluates the composition, diversity, regeneration density and abundance of natural regeneration of tree species in gaps in undisturbed, intermittently disturbed, and disturbed forest sites. Bia Tano Forest Reserve in Ghana was the study area and three gaps each were selected in the three forest site categories. Ten circular subsampling areas of 1 m2 were delineated at 2 m spacing along north, south, east, and west transects within individual gaps. Data on natural regeneration < 350 cm height were gathered. The results show that the intensity of disturbance was disproportional to gap size. Species diversity differed significantly between undisturbed and disturbed sites and, also between intermittently disturbed and disturbed sites for Simpson’s (1-D), Equitability (J), and Berger–Parker (B–P) indices. However, there was no significant difference among forest sites for Shannon diversity (H) and Margalef richness (MI) indices. Tree species composition on the sites differed. Regeneration density on the disturbed site was significantly higher than on the two other sites. Greater abundance and density of shade-dependent species on all sites identified them as opportunistic replacements of gap-dependent pioneers. Pioneer species giving way to shade tolerant species is a natural process, thus make them worst variant in gap regeneration.

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Species composition of climbers in seasonal semideciduous forest fragments of Southeastern Brazil

Biota Neotropica ◽

10.1590/s1676-06032009000400018 ◽

2009 ◽

Vol 9 (4) ◽

pp. 175-188 ◽

Cited By ~ 25

Author(s):

Karin dos Santos ◽

Luiza Sumiko Kinoshita ◽

Andréia Alves Rezende

Keyword(s):

Floristic Composition ◽

Southeastern Brazil ◽

Forest Site ◽

Forest Fragments ◽

Semideciduous Forest ◽

Number Of Species ◽

Forest Sites ◽

Forest Remnants ◽

Mean Similarity ◽

Made In

In this study we evaluated floristic composition patterns of communities of climbers within ten inventories carried out in semideciduous forest fragments of southeastern Brazil. One of the inventories is original, being carried out for the present study in Ribeirão Cachoeira forest, Campinas, São Paulo State, Southeastern Brazil. This inventory was then pooled together to other nine climbers' inventories made in other forests of Southeastern Brazil to form a data base, which was examined regarding species richness, similarity, species distribution and climbing methods. The total number of species obtained was 355, belonging to 145 genera and 43 families. The ten most diverse families Bignoniaceae (45 species), Fabaceae (42), Malpighiaceae (36), Asteraceae (31), Apocynaceae (29), Sapindaceae (28), Convolvulaceae (21), Cucurbitaceae (14), Passifloraceae (10), and Euphorbiaceae (8) contributed to 74.4% of the total number of species recorded. The commonest climbing method in the studied sites was main stem or branch twining, accounting for 178 species or 50.1% of the total, the second commonest was tendril climbing (121 species, 34.1%), and the least, scrambling (56 species, 15.8%). We found a high percentage of exclusive species i.e., those occurring in only one forest site, which accounted for 49.3% of the total recorded. The mean similarity among forest sites (30%) may be considered low. The climbing species contribution to the total wood plant richness recorded on the forests sites was very high in some of the sites (up to 52.5%). These results indicated the importance of climber communities to plant diversity for semideciduous forests in Southeastern Brazil, enhancing the regional diversity and the conservation value of these forest remnants.

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Seed longevity of maize conserved under germplasm bank conditions for up to 60 years

Annals of Botany ◽

10.1093/aob/mcab009 ◽

2021 ◽

Author(s):

Filippo Guzzon ◽

Maraeva Gianella ◽

Jose Alejandro Velazquez Juarez ◽

Cesar Sanchez Cano ◽

Denise E Costich

Keyword(s):

Seed Germination ◽

Plant Genetic Resources ◽

Seed Viability ◽

Storage Conditions ◽

Seed Longevity ◽

Germplasm Bank ◽

Significant Difference ◽

Different Temperatures ◽

Germination Experiments

Abstract Background and Aims The long-term conservation of seeds of plant genetic resources is of key importance for food security and preservation of agrobiodiversity. Nevertheless, there is scarce information available about seed longevity of many crops under germplasm bank conditions. Methods Through germination experiments as well as the analysis of historical monitoring data, we studied the decline in viability manifested by 1000 maize (Zea mays subsp. mays) seed accessions conserved for an average of 48 years at the CIMMYT germplasm bank, the largest maize seedbank in the world, under two cold storage conditions: an active (–3 °C; intended for seed distribution) and a base conservation chamber (–15 °C; for long-term conservation). Key Results Seed lots stored in the active chamber had a significantly lower and more variable seed germination, averaging 81.4 %, as compared with the seed lots conserved in the base chamber, averaging 92.1 %. The average seed viability detected in this study was higher in comparison with that found in other seed longevity studies on maize conserved under similar conditions. A significant difference was detected in seed germination and longevity estimates (e.g. p85 and p50) among accessions. Correlating seed longevity with seed traits and passport data, grain type showed the strongest correlation, with flint varieties being longer lived than floury and dent types. Conclusions The more rapid loss of seed viability detected in the active chamber suggests that the seed conservation approach, based on the storage of the same seed accessions in two chambers with different temperatures, might be counterproductive for overall long-term conservation and that base conditions should be applied in both. The significant differences detected in seed longevity among accessions underscores that different viability monitoring and regeneration intervals should be applied to groups of accessions showing different longevity profiles.

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Effect of light and temperature on seed germination in Tibouchina mutabilis (Vell.) Cogn. (Melastomataceae)

Biota Neotropica ◽

10.1590/s1676-06032008000200006 ◽

2008 ◽

Vol 8 (2) ◽

pp. 63-68 ◽

Cited By ~ 5

Author(s):

Edson Simão ◽

Massanori Takaki

Keyword(s):

Seed Germination ◽

White Light ◽

Light Sensitivity ◽

Pioneer Species ◽

Continuous Darkness ◽

Effect Of Light

The effect of light and temperature on Tibouchina mutabilis seed germination was analyzed by isothermic incubations in the range of 10 to 40 °C, with 5 °C intervals under both continuous white light (32.85 µmolm-2s-1) and darkness and alternating temperatures (15-20; 15-25; 15-30; 15-35; 20-25; 20-30; 20-35; 25-30; 25-35 and 30-35 °C) under both photoperiod of 12 hours and continuous darkness. The seeds of T. mutabilis need light to trigger the germination and no germination was observed in darkness. The range of optimum temperatures for germination was between 25 to 30 °C and the 20-25 °C alternating temperatures. These results indicate that T. mutabilis behaves as a pioneer species and daily alternating temperatures did not change the light sensitivity of seeds.

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Evaluation of Snow Albedo in Land Models for Weather and Climate Studies

Journal of Applied Meteorology and Climatology ◽

10.1175/2009jamc2134.1 ◽

2010 ◽

Vol 49 (3) ◽

pp. 363-380 ◽

Cited By ~ 46

Author(s):

Zhuo Wang ◽

Xubin Zeng

Keyword(s):

Climate Models ◽

Snow Water Equivalent ◽

Weather Forecasting ◽

Vegetation Type ◽

Global Model ◽

Forest Site ◽

Snow Albedo ◽

Community Land Model ◽

In Situ Data ◽

Forest Sites

Abstract Snow albedo plays an important role in land models for weather, climate, and hydrometeorological studies, but its treatment in various land models still contains significant deficiencies. Complementary to previous studies that evaluated the snow albedo as part of an overall land model study, the snow albedo formulations as used in four major weather forecasting and climate models [European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP) “Noah” land model, National Center for Atmospheric Research (NCAR) Community Land Model (CLM3), and NCEP global model] were directly evaluated here using multiyear Boreal Ecosystem–Atmosphere Study (BOREAS) in situ data over grass and forest sites. First, four idealized cases over grass and forest sites were designed to understand better the different albedo formulations in these models. Then the BOREAS data were used to evaluate snow albedo and relevant formulations and to identify deficiencies of each model. Based on these analyses, suggestions that involve only minor changes in parameters or formulations were made to significantly reduce these deficiencies of each model. For the ECMWF land model, using the square root of snow water equivalent (SWE), rather than SWE itself, in the computation of snow fraction would significantly reduce the underestimation of albedo over grass. For the NCEP Noah land model, reducing (increasing) the critical SWE for full snow cover over short (tall) vegetation would reduce the underestimate (overestimate) of snow albedo over the grass (forest) site. For the NCAR CLM3, revising the coefficient used in the ground snow-fraction computation would substantially reduce the albedo underestimation over grass. For the albedo formulations in the NCEP global model, replacing the globally constant fresh snow albedo by the vegetation-type-dependent Moderate-Resolution Imaging Spectroradiometer (MODIS) maximum snow albedo would significantly improve the overestimation of model albedo over forest.

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Using Microwave Soil Heating to Inhibit Invasive Species Seed Germination

Invasive Plant Science and Management ◽

10.1017/inp.2017.29 ◽

2017 ◽

Vol 10 (3) ◽

pp. 262-270 ◽

Cited By ~ 7

Author(s):

Mélissa De Wilde ◽

Elise Buisson ◽

Nicole Yavercovski ◽

Loïc Willm ◽

Livia Bieder ◽

...

Keyword(s):

Invasive Species ◽

Soil Moisture ◽

Seed Germination ◽

Invasive Plant ◽

Organic Matter Content ◽

Seed Viability ◽

Germination Percentage ◽

Matter Content ◽

Burial Depth ◽

Experimental Conditions

Successful invasive plant eradication is rare, because the methods used target the adult stage, not taking into account the development capacity of a large seedbank. Heating by microwave was considered, because it offers a means to quickly reach the temperature required for loss of seed viability and inhibition of germination. Previous results were not encouraging, because homogeneous and deep-wave penetration was not achieved, and the various parameters that can affect treatment effectiveness were incompletely addressed. This study aimed to determine, under experimental conditions, the best microwave treatment to inhibit invasive species seed germination in terms of power (2, 4, 6 kW) and duration (2, 4, 8 min) of treatments and depending on soil moisture (10%, 13%, 20%, 30%) and seed burial depth (2, 12 cm). Three invasive species were tested: Bohemian knotweed, giant goldenrod, and jimsonweed. The most effective treatments required relatively high power and duration (2kW8min, 4kW4min, 6kW2min, and 6kW4min; 4kW8min and 6kW8min were not tested for technical reasons), and their effectiveness diminished with increasing soil moisture with germination percentage between 0% and 2% for the lowest soil moisture, 0% and 56% for intermediate soil moisture, and 27% and 68% in control treatments. For the highest soil moisture, only 2kW8min and 4kW4min reduced germination percentage between 2% and 19%. Occasionally, germination of seeds located at the 12-cm depth was more strongly affected. Giant goldenrod seeds were the most sensitive, probably due to their small size. Results are promising and justify further experiments before developing a field microwave device to treat large volumes of soil infested by invasive seed efficiently and with reasonable energy requirements. Other types of soil, in terms of texture and organic matter content, should be tested in future experiments, because these factors influence soil water content and, consequently, microwave heating.

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Ecology of cultivable yeasts in pristine forests in northern Patagonia (Argentina) influenced by different environmental factors

Canadian Journal of Microbiology ◽

10.1139/cjm-2013-0897 ◽

2014 ◽

Vol 60 (6) ◽

pp. 371-382 ◽

Cited By ~ 14

Author(s):

María Cecilia Mestre ◽

Sonia Fontenla ◽

Carlos A. Rosa

Keyword(s):

Environmental Factors ◽

Volcanic Activity ◽

Forest Site ◽

Nothofagus Pumilio ◽

Species Accumulation Curves ◽

Environmental Characteristics ◽

Factors Affecting ◽

Complex Interactions ◽

Forest Sites ◽

Nothofagus Antarctica

Environmental factors influencing the occurrence and community structure of soil yeasts in forests are not well studied. There are few studies dedicated to Southern Hemisphere soil yeasts populations and even fewer focused on temperate forests influenced by volcanic activity. The present work aimed to study the ecology of soil yeast communities from pristine forests influenced by different environmental factors (precipitation, physicochemical properties of soil, tree species, soil region, and season). The survey was performed in 4 northern Patagonian forests: 2 dominated by Nothofagus pumilio and 2 by Nothofagus antarctica. Yeast communities were described with ecological indices and species accumulation curves, and their association with environmental characteristics was assessed using multivariate analysis. Each forest site showed a particular arrangement of species as a result of environmental characteristics, such as dominant plant species, nutrient availability, and climatic characteristics. Cryptococcus podzolicus was most frequently isolated in nutrient-rich soils, Trichosporon porosum dominated cold mountain forests with low nutrient and water availability in soil, and capsulated yeasts such as Cryptococcus phenolicus dominated forest sites with low precipitation. The present work suggests that environmental factors affecting yeast communities may not be the current soil characteristics but the result of complex interactions of factors including natural disturbances like volcanic activity.

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Seed-dispersal and seedling recruitment patterns by the last Neotropical megafaunal element in Amazonia, the tapir

Journal of Tropical Ecology ◽

10.1017/s0266467400001462 ◽

2000 ◽

Vol 16 (3) ◽

pp. 369-385 ◽

Cited By ~ 81

Author(s):

José M. V. Fragoso ◽

Jean M. Huffman

Keyword(s):

Seedling Recruitment ◽

Germination Rate ◽

Seed Viability ◽

Seed Rain ◽

Dry Land ◽

Forest Sites ◽

Seed Dispersion ◽

Tapirus Terrestris ◽

Spatio Temporal ◽

Seed Shadows

Tapirs (Tapiridae) are the last representatives of the Pleistocene megafauna of South and Central America. How they affect the ecology of plants was examined by studying the diversity, abundance, and condition of seeds defecated by the lowland tapir (Tapirus terrestris) in Amazonian Brazil. Additionally, the spatio-temporal pattern of the seed-rain and seed-shadows generated by tapirs was recorded. Three hundred and fifty-six tapir faeces were examined. Eleven per cent were found in water (n = 41), while 88% were located on dry land (n = 315). Of those found on dry land, 84% were located at sites that flood seasonally, while 14% of the total were encountered at forest sites that do not flood. In 127 faeces checked in the laboratory over 12 906 seeds of at least 39 species were found. Seed viability ranged from 65% for Maximiliana maripa to 98% for Enterolobium schomburgkii. Of nine seed species planted in the laboratory, seven germinated within 4 wk, with one species achieving an 89% germination rate. For many species recruitment to the seedling stage was also high under natural conditions, with 13 plant species occurring as seedlings in older faeces. Tapir generated seed-rain occurred throughout the year, with seeds defecated in all months. Two temporal patterns in species seed rain occurred: (1) contiguous monthly occurrence with peaks in abundance, and (2) discontinuous occurrence (time clumped) with small (a few months) to large (many months to more than a year) temporal gaps. The highest diversity of seeds appeared in April, at the end of the dry season. As the last of the Pleistocene megafauna of the region, tapirs may have particular importance as dispersers of large seeds and generators of unique seed dispersion patterns.

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Non-Deep Physiological Dormancy in Seed and Germination Requirements of Lysimachia coreana Nakai

Horticulturae ◽

10.3390/horticulturae7110490 ◽

2021 ◽

Vol 7 (11) ◽

pp. 490

Author(s):

Saeng Geul Baek ◽

Jin Hyun Im ◽

Myeong Ja Kwak ◽

Cho Hee Park ◽

Mi Hyun Lee ◽

...

Keyword(s):

Seed Germination ◽

Seed Dormancy ◽

Germination Rate ◽

Seed Viability ◽

Cold Stratification ◽

Dormancy Breaking ◽

Viability Test ◽

Physiological Dormancy ◽

Different Temperatures ◽

Germination Requirements

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA3) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L−1 GA3. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA3 demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L−1 GA3 (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA3 treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L−1 GA3 treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.

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Stand Structure, Productivity and Carbon Sequestration Potential of Oak Dominated Forests in Kumaun Himalaya

Current World Environment ◽

10.12944/cwe.11.2.15 ◽

2016 ◽

Vol 11 (2) ◽

pp. 466-476

Author(s):

Bijendra Lal ◽

L.S. Lodhiyal

Keyword(s):

Carbon Sequestration ◽

Primary Productivity ◽

Tree Species ◽

Stand Structure ◽

Basal Area ◽

Forest Site ◽

Forest Sites ◽

Sequestration Potential ◽

Oak Tree ◽

Quercus Leucotrichophora

Present study deals with stand structure, biomass, productivity and carbon sequestration in oak dominated forests mixed with other broad leaved tree species. The sites of studied forests were located in Nainital region between 29058’ N lat. and 79028’ E long at 1500-2150 m elevation. Tree density of forests ranged from 980-1100 ind.ha-1. Of this, oak trees shared 69-97%. The basal area of trees was 31.81 to 63.93 m2 ha-1. R. arboreum and Q. floribunda shared maximum basal area 16.45 and 16.32 m2 ha-1, respectively in forest site-1 and 2 while Quercus leucotrichophora shared maximum (35.69 m2 ha-1) in site-3. The biomass and primary productivity of tree species ranged from 481-569 t ha-1 and 16.9-20.9 t ha-1yr-1, respectively. Of this, biomass and primary productivity of oak tree species accounted for 81 to 95 and 78 to 98%, respectively. Carbon stock and carbon sequestration ranged from 228 to 270 t ha-1 and 8.0 to 9.9 t ha-1yr-1, respectively. The share of oak tree species ranged from 81 to 94.7 and 79 to 97%, respectively. The diversity of tree species ranged from 0.03 to 0.16 in forest sites-1, 2 and 3. The diversity of oak species was 0.08-0.16 in all the forest sites. Thus it is concluded that among the oak tree species, Quercus floribunda and Quercus leucotrichophora were highly dominated in the studied forests. The climax form of oak dominated trees in the studied forest sites depicted slightly lower richness and diversity of tree species compared to the forests in the region and elsewhere. As far as dry matter and carbon of forests is concerned, these estimates are close to the earlier reports of forests in the region. Therefore, studied forests have the potential to increase the diversity, productivity and carbon sequestration of forest tree species by providing the adequate scientific conservation and management inputs.

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