scholarly journals Variation in stage structure and fitness traits between road verge and meadow populations of Colchicum autumnale (Liliaceae): Effects of habitat quality

2011 ◽  
Vol 75 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Lucyna Mróz
Keyword(s):  
Reproductive Success ◽  
Population Size ◽  
Habitat Quality ◽  
Plant Density ◽  
Habitat Type ◽  
Stage Structure ◽  
Soil Characteristics ◽  
Stepwise Multiple Regression ◽  
Colchicum Autumnale ◽  
Significant Difference

The frequency distribution and density of three life stages as well as fitness components of the perennial plant <em>Colchicum autumnale</em> growing in the unmanaged road verges and in the extensive mown and grazed meadows in the Sudeten Mts. were studied. Furthermore, investigated were the effects of population size and plant size (measured as number of flowers) on reproductive success and explored if variation in reproductive and vegetative traits of adults could be associated with soil characteristics. The t-test indicated that proportions of subadults and reproductive adults were significantly lower in verge than in meadow populations, and of vegetative adults significantly higher. The plant density of reproductive adults and the reproductive adults to all adults ratio were significantly lower in verge populations compared to meadow populations. Although habitat type accounted for significant variation in stage structure, no significant difference was found between vegetative and reproductive traits in adult plants, except for the number of flowers. In verge populations the number of flowers was significantly lower as compared to meadow populations. The traits related to reproduction were not significantly influenced by population size. However, the proportion of flowers setting fruit decreased significantly with increasing number of flowers. The stepwise multiple regression revealed significant relationships between soil characteristics and number of fruits per plant, fruit set, number seeds per plant and number of leaves in vegetative adults. The results suggest that the creation of the low and relatively open vegetation cover could increase the chance of persistence of <em>C. autumnale</em> living in verge habitats by promoting of seed germination, seedling establishment and flowering, and they also show that the reproductive success and vegetative components of fitness are most likely influenced by habitat quality.

scholarly journals Heliconia acuminata reproductive success is independent of local floral density

2004 ◽  
Vol 34 (3) ◽  
pp. 467-471 ◽  
Author(s):  
Emilio M. Bruna ◽  
W. John Kress ◽  
Francisco Marques ◽  
Osmaildo Ferreira da Silva
Keyword(s):  
Reproductive Success ◽  
Neighborhood Effects ◽  
Plant Density ◽  
Threshold Value ◽  
Major Effect ◽  
Flowering Plant ◽  
Pollinator Visitation ◽  
Female Function ◽  
Significant Difference ◽  
Floral Density

Reproductive plants in tropical forests are patchily distributed, with some in large aggregations of reproductive consepecifics while others are relatively isolated. This variation in floral density is hypothesized to have a major effect on plant reproductive success, since individuals in higher density neighborhoods can attract more or higher quality pollinators. We experimentally tested this hypothesis with populations of the understory herb Heliconia acuminata in central Amazonia. We created replicated plots in which reproductive plant density spanned the range of naturally occurring floral neighborhood size, then measured three surrogates of plant fitness in focal plants in each array. There was no significant difference between any of the three floral neighborhood treatments in total seed production, fruit set, or the number of seeds produced per fruit. Pollinator visitation rates to plants in all treatments were extremely low, with many plants not visited at all during the observation period. This could be because H. acuminata's hummingbird pollinators are unable to find the widely scattered reproductive plants, however this hypothesis appears unlikely. Instead, natural flowering plant densities may simply be below the threshold value at which neighborhood effects become important, even in "high-density" aggregations. Nutrient limitation, selective fruit abortion, and reproduction via male rather than female function may also be playing a role. We argue the absence of neighborhood effects may be a general phenomenon in central Amazonian forests, though additional experiments with other plant-pollinator systems are needed to determine the extent to which this hypothesis is supported.

scholarly journals A comparative study on the reproductive success of two rewarding Habenaria species (Orchidaceae) occurring in roadside verge habitats

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wenliu Zhang ◽  
Jiangyun Gao
Keyword(s):  
Reproductive Success ◽  
Fruit Set ◽  
Plant Density ◽  
Flowering Plant ◽  
Floral Display ◽  
Pollinator Behaviour ◽  
Factors Affecting ◽  
Nectar Sugar ◽  
Viable Seeds ◽  
Viable Embryo

Abstract Background Most orchid species have been shown to be severely pollination limited, and the factors affecting reproductive success have been widely studied. However, the factors determining the reproductive success vary from species to species. Habenaria species typically produce nectar but exhibit variable fruit set and reproductive success among species. Here, we investigated the influence of the flowering plant density, inflorescence size, breeding system, and pollinator behaviour on the reproductive success of two rewarding Habenaria species. Results Our observations indicated that Habenaria limprichtii and H. petelotii co-occur in roadside verge habitats and present overlapping flowering periods. Both species were pollination limited, although H. limprichtii produced more fruits than H. petelotii under natural conditions during the 3-year investigation. H. petelotii individuals formed distinct patches along roadsides, while nearly all H. limprichtii individuals clustered together. The bigger floral display and higher nectar sugar concentration in H. limprichtii resulted in increased attraction and visits from pollinators. Three species of effective moths pollinated for H. limprichtii, while Thinopteryx delectans (Geometridae) was the exclusive pollinator of H. petelotii. The percentage of viable seeds was significantly lower for hand geitonogamy than for hand cross-pollination in both species. However, H. limprichtii may often be geitonogamously pollinated based on the behaviours of the pollinators and viable embryo assessment. Conclusions In anthropogenic interference habitats, the behaviours and abundance of pollinators influence the fruit set of the two studied species. The different pollinator assemblages in H. limprichtii can alleviate pollinator specificity and ensure reproductive success, whereas the more viable embryos of natural fruit seeds in H. petelotii suggested reducing geitonogamy by pollinators in the field. Our results indicate that a quantity-quality trade-off must occur between species with different breeding strategies so that they can fully exploit the existing given resources.

scholarly journals Conservation, Restoration, and Sustainable Use of Biodiversity Based on Habitat Quality Monitoring: A Case Study on Jeju Island, South Korea (1989–2019)

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 774
Author(s):  
Hyun-Jung Hong ◽  
Choong-Ki Kim ◽  
Hyun-Woo Lee ◽  
Woo-Kyun Lee
Keyword(s):  
South Korea ◽  
Habitat Quality ◽  
Sustainable Use ◽  
Habitat Type ◽  
Biodiversity Loss ◽  
Well Being ◽  
Jeju Island ◽  
Natural Habitats ◽  
Invest Model ◽  
Aichi Biodiversity Targets

Biodiversity loss is progressing despite biodiversity being essential for human survival, prosperity, and well-being. Conservation, restoration, and sustainable use of the habitat, given that its change is the most prominent factor causing the deterioration of biodiversity, represents a highly effective way of securing biodiversity. Therefore, we assessed and monitored habitat quality as a proxy for biodiversity with habitat quantity in Jeju Island, South Korea. We used an InVEST model with data on the habitat type, suitability, sensitivity, accessibility, and threat factors. Natural habitats throughout Jeju had rapidly decreased in area by 24.9% from 1989 to 2019, and this change contributed to the degradation of habitat quality by 15.8%. We provided significant evidence on the critical degradation of habitat for a long period of over 30 years and highlighted the urgent need for policies and behaviors that enhance biodiversity. We proposed appropriate strategies to prompt people to conserve better, restore effectively, and use biodiversity sustainably. We expect that our findings will provide scientific and evidence-based guidance for policy-making on biodiversity enhancement and will further support achievement of the Sustainable Development Goals and Aichi Biodiversity Targets, in addition to compliance with the New Deal for Nature and People.

scholarly journals Rapid declines in habitat quality and population size of the Liben (Sidamo) Lark Heteromirafra sidamoensis necessitate immediate conservation action – ERRATUM

2010 ◽  
Vol 20 (2) ◽  
pp. 214-214 ◽  
Author(s):  
PAUL F. DONALD ◽  
GRAEME M. BUCHANAN ◽  
NIGEL J. COLLAR ◽  
YILMA DELLELEGN ABEBE ◽  
MERID N. GABREMICHAEL ◽  
...  
Keyword(s):  
Population Size ◽  
Habitat Quality ◽  
Conservation Action

Plant height and height of the main ear in maize (Zea mays L.) at different locations and different plant densities

2002 ◽  
Vol 50 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Z. Gyenes-Hegyi ◽  
I. Pók ◽  
L. Kizmus ◽  
Keyword(s):  
Plant Height ◽  
Plant Density ◽  
Close Correlation ◽  
Plant Size ◽  
Considerable Effect ◽  
Maximum Height ◽  
The Best Approximation ◽  
Significant Difference ◽  
Plant Densities ◽  
Ear Height

The plant height and the height of the main ear were studied over two years in twelve single cross maize hybrids sown at three different plant densities (45, 65 and 85 thousand plants/ha) at five locations in Hungary (Keszthely, Gönc, Gyöngyös, Sopronhorpács, Martonvásár). The results revealed that plant height and the height of the main ear are important variety traits and are in close correlation with each other. It was found that the hybrids grew the tallest when the genetic distance between the parental components was greatest (Mv 4, Mv 5). The height of the main ear was also the greatest in these hybrids, and the degree of heterosis was highest (193% for plant height, 194% for the height of the main ear). The shortest hybrids were those developed between related lines (Mv 7, Mv 11). In this case the heterosis effect was the lowest for both plant height (128%) and the height of the main ear (144%). The ratio of the height of the main ear to the plant height was stable, showing little variation between the hybrids (37–44%). As maize is of tropical origin it grows best in a humid, warm, sunny climate. Among the locations tested, the Keszthely site gave the best approximation to these conditions, and it was here that the maize grew tallest. The dry, warm weather in Gyöngyös stunted the development of the plants, which were the shortest at this location. Plant density had an influence on the plant size. The plants were shortest when sown at a plant density of 45,000 plants/ha, and the main ears were situated the lowest in this case. At all the locations the plant and main ear height rose when the plant density was increased to 65,000 plants/ha. At two sites (Gönc and Sopronhorpács) the plants attained their maximum height at the greatest plant density (85,000 plants/ha). In Keszthely there was no significant difference between these two characters at plant densities of 65 and 85 thousand plants/ha, while in Gyöngyös and Martonvásár the greatest plant density led to a decrease in the plant and main ear height. The year had a considerable effect on the characters tested.

Flood disturbance and shade stress shape the population structure of açaí palm Euterpe precatoria, the most abundant Amazon species

Botany ◽  
2020 ◽  
Vol 98 (3) ◽  
pp. 147-160
Author(s):  
Heloisa Dantas Brum ◽  
Alexandre F. Souza
Keyword(s):  
Population Structure ◽  
Population Size ◽  
Size Distribution ◽  
Amazon Basin ◽  
Habitat Type ◽  
Forest Products ◽  
Life Stages ◽  
Disturbance Regime ◽  
Human Settlements ◽  
Human Management

Euterpe precatoria Mart. is the most abundant plant species in the Amazon basin, and one of the main non-timber forest products on the continent. A thorough understanding of the ecology of this species is needed to support sustainable management initiatives. Resource availability, disturbance regime, and human management are some of the main factors influencing population structure. We described the species’ life stages, evaluated its allometric relationships, and assessed the effects of habitat type (floodplain and upland) and proximity to human settlements on population size distribution in the Central Amazon near the Purus River. The height:diameter ratio increased from Seedlings to Juvenile 2, but decreased from Juvenile 2 to Reproductive 2, indicating changing height investment for any given diameter along these life stages. There was a marked habitat dependency in both the density and population size distribution, with populations in upland forests dominated by juveniles, whereas populations in the floodplains were dominated by reproductive palms. Proximity to human settlements was not related to population structure parameters. Our results suggest that the disturbance regime may have opposite meanings in várzea forests, where it limits recruitment under increased light levels, and in terra firme forests, where it may stimulate recruitment under limited light conditions.

Effect of plant density on the expression of the creeping-rooted character and forage yield of the lucerne (Medicago sativa) cultivar Cancreep

1974 ◽  
Vol 14 (71) ◽  
pp. 735 ◽  
Author(s):  
H Daday ◽  
A Grassia ◽  
J Peak
Keyword(s):  
Medicago Sativa ◽  
Plant Density ◽  
Survival Rates ◽  
Forage Yield ◽  
Forage Production ◽  
Crown Diameter ◽  
High Plant Density ◽  
Significant Difference

The effects of plant density, grass competition and weedicide spraying on the expression of the creeping-rooted character, crown development and on forage production of Cancreep were investigated in swards of hand-planted seedlings, and in a sown experiment. Higher percentages of creeping-rooted plants and increased crown development were found at low plant density whereas high plant density suppressed both creep and crown development. Weedicide spraying treatments increased the percentage of creeping plants in the sown experiment. The best survival rates of cocksfoot and optimum expressions of creep were also found at low densities when these species were grown in competition. The minimum mean crown diameter of plants initiating creep was 9.4 cm in the planted experiment. No significant difference was found between forage production of Cancreep and Hunter River in the sown experiment. The optimum sowing rate for Cancreep is about one kg ha-1, rows 30 cm to 60 cm apart and an application of the weedicide Diuron is recommended before the commencement of the winter after establishment.

scholarly journals Profiling the Bacterial Diversity in a Typical Karst Tiankeng of China

Biomolecules ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 187 ◽  
Author(s):  
Gaozhong Pu ◽  
Yanna Lv ◽  
Lina Dong ◽  
Longwu Zhou ◽  
Kechao Huang ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Bacterial Communities ◽  
Soil Microorganisms ◽  
Operational Taxonomic Unit ◽  
Soil Characteristics ◽  
Soil Samples ◽  
Controlling Factors ◽  
Bacterial Composition ◽  
Microbial Distribution ◽  
Significant Difference

While karst tiankengs have a higher capacity to act as safe havens for biodiversity in changing climates, little is known about their soil microorganisms. To fill this gap, we investigate the distribution and driving factors of the bacterial community in karst tiankeng systems. There is a significant difference in the soil characteristics between the inside and the outside of a karst tiankeng. At the karst tiankeng considered in this study, the bacterial composition, in terms of the operational taxonomic unit (OTU), was found to be significantly different in different soil samples, taken from diverse sampling sites within the collapsed doline or the external area, and showed a high habitat heterogeneity. The dominant phylum abundances vary with the sampling sites and have their own indicator taxa from phylum to genus. Unlike the primary controlling factors of plant diversity, the microclimate (soil moisture and temperature), soil pH, and slope dominated the distribution of the bacterial community in karst tiankeng systems. Our results firstly showed the distribution characteristics of bacterial communities and then revealed the importance of microhabitats in predicting the microbial distribution in karst tiankeng systems.

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