scholarly journals Características foliares y tasas vitales de árboles sucesionales tardíos de un bosque tropical perennifolio

2019 ◽  
Vol 86 ◽  
pp. 1
Author(s):  
Cristina Martínez Garza ◽  
Henry F. Howe
Keyword(s):  
Growth Rates ◽  
Tree Species ◽  
Secondary Forest ◽  
High Growth ◽  
Structural Diversity ◽  
High Plasticity ◽  
Leaf Production ◽  
Pimenta Dioica ◽  
One Year ◽  
Leaf Survival

Restoration of vegetation in perturbed areas (e.g., abandoned pastures) with late-successional tree species may help to bypass decades of low diversity by accelerating succession. To elucidate how leaf dynamics is related to high growth rates and survival in early successional environments, we evaluated the hypothesis that plasticity in foliar demography is positively related to establishment of seven late-successional tree species growing in sunny sites (pasture and edge) and dark sites (secondary forest) at Los Tuxtlas, Veracruz, Mexico. We monitored leaves from 517 individuals from all species at all habitats during one year. Individuals growing in secondary forest and edge showed higher leaf survival and lower leaf production than those growing in pasture. Individuals with higher growth rates and survival in pasture showed high plasticity in their leaf survival and low plasticity in their leaf production (stability) while individuals in edge and secondary forest with high survivorship were those with high stability in their leaf production. Our results indicate that <em>Nectandra ambigens, Licaria velutina</em> and <em>Pouteria rhynchocarpa</em> may be planted in pastures because they show high growth rates and survival there, besides, they have different maximal height as adults and therefore they will provide structural diversity to the restored forest. Species with low plant survivorship in pastures as <em>Calophyllum brasiliense, Pimenta dioica, Amphitecna tuxtlensis</em> and <em>Eugenia inirebensis</em> should be planted in great numbers or until a canopy of pioneers develop.

Canopy knockdown of arthropods in exotic plantations and natural forest in Sabah, north-east Borneo, using insecticidal mist-blowing

1998 ◽  
Vol 88 (1) ◽  
pp. 15-24 ◽  
Author(s):  
V.K. Chey ◽  
J.D. Holloway ◽  
C. Hambler ◽  
M.R. Speight
Keyword(s):  
Tree Species ◽  
Secondary Forest ◽  
Acacia Mangium ◽  
Natural Forest ◽  
Pinus Caribaea ◽  
North East ◽  
Arthropod Species ◽  
Exotic Tree ◽  
Arthropod Biodiversity ◽  
One Year

AbstractCanopy knockdown of arthropods using mist-blowing was carried out in Brumas, Sabah (north-east Borneo), in plantations of exotic (non-indigenous) tree species (Acacia mangium, Eucalyptus deglupta, Gmelina arborea, Paraserianthes [=Albizia] falcataria, and Pinus caribaea), plus secondary natural forest and dense understorey within E. deglupta stands. Each habitat had three 1 m2 samples taken four times in one year. The average arthropod species richness within the stands of the exotic tree species ranged from 27 in E. deglupta, to 68 in natural, secondary forest. The total number of individuals caught ranged from 137 in G. arborea to 1628 in secondary forest. The dense and plant-species rich understorey within E. deglupta stands yielded both higher numbers of species and individuals than the eucalypt trees themselves, indicating the importance of allowing the development of a luxuriant understorey for the enhancement of conservation and biodiversity. Though arthropod biodiversity is reduced by the conversion of tropical forests to plantations, abundance and richness are still substantial in the latter habitats.

Soil moisture gradients and climate change: predicting growth of a critical boreal tree species

2020 ◽  
Vol 50 (10) ◽  
pp. 1074-1080
Author(s):  
Caleb McCollum ◽  
Inés Ibáñez
Keyword(s):  
Soil Moisture ◽  
Growth Rates ◽  
Tree Species ◽  
Pinus Banksiana ◽  
Climatic Variability ◽  
High Growth ◽  
Spring Temperature ◽  
Extreme Habitats ◽  
Complex Relationships ◽  
Moisture Conditions

Understanding the complex relationships among climate, tree growth, and water availability is key for predicting the performance of environmentally and economically salient tree species like Pinus banksiana Lamb. Ecologically, P. banksiana occupies the extreme habitats of soil moisture gradient, from very sandy dry soils to waterlogged bogs. However, little is known about how its growth may be affected by future climate in these two habitats. We assessed the effect of climatic variability on the growth of this species under different moisture conditions (sandy dry soils and bogs). Trees in the bog site had the highest growth rates. Individuals in all sites responded positively to increased spring temperature, whereas those in the bog site showed the highest response to increased summer moisture. However, in dry years, growth response in the bog site declined by 17%, whereas in the two drier sites, growth declined between 1% and 9.6%, equalizing growth rates across sites. Further, the decline in growth associated with drier summers eliminated the benefits of warmer springs at the bog site. Sites near bogs are currently associated with high growth performance and are commonly planted with this species. Yet, under the projected climate for the region, trees growing in these sites will likely lose their advantage.

scholarly journals Experimental testing of density- and season-dependent growth in vegetative Fucus aquaculture and modelling of growth over one year for different cultivation scenarios

2021 ◽  
Author(s):  
Rafael Meichssner ◽  
Peter Krost ◽  
Rüdiger Schulz
Keyword(s):  
Growth Rates ◽  
Experimental Testing ◽  
Vegetative Reproduction ◽  
High Growth ◽  
Fucus Vesiculosus ◽  
Seasonal Growth ◽  
Density Relationship ◽  
Different Seasons ◽  
Dependent Growth ◽  
One Year

AbstractIn the Kiel Fjord, western Baltic Sea, an experimental culture of Fucus vesiculosus and Fucus serratus has been established in order to develop a sustainable method for biomass production of these species. The cultivation method includes the unattached rearing of fronds in drifting baskets and their vegetative reproduction by cutting of small vegetative apices. In this study, we performed culture experiments to measure growth rates with this method at different initial stocking densities (1–5 kg m−2) and during different seasons of the year. Using the results, we modelled growth over 1 year for different cultivation scenarios (different initial stocking densities (1–4.75 kg m−2) and harvest densities (1.25–5 kg m−2)) in order to identify optimal scenarios and estimate annual yields and the number of necessary harvests in these scenarios. Fucus vesiculosus showed a parabolic yield–density relationship with decreasing yields at high initial stocking densities (> 2.5 kg m−2). In contrast, F. serratus showed an asymptotic yield–density relationship with rather constant yields at high initial stocking densities. Both species showed a typical seasonal growth pattern with low growth rates during winter and high growth rates during summer; however, F. serratus seemed to be growth limited during summer which was not observed for F. vesiculosus. The modelling results reflected the results of the Density experiment: for F. vesiculosus, optimal cultivation scenarios were found for intermediate cultivation densities (initial stocking densities, 1.75–2.25 kg m−2; harvest densities, 3–4 kg m−2); for F. serratus, optimal cultivation scenarios included higher densities (initial stocking densities, 2.5–4 kg m−2; harvest density, 5 kg m−2). The model scenarios predicted maximal annual yields of 6.65–6.76 kg m−2 for F. vesiculosus and 6.88–6.99 kg m−2 for F. serratus. For both species, the number of harvests necessary to achieve these yields varied depending on the cultivation scenario from 2 to 6. Scenarios with only 1 harvest per year yielded slightly lower annual yields. We conclude that the modelling results offer a valid and helpful orientation for future efforts to produce Fucus species in commercial culture.

How Fast Can Firms Grow?

2014 ◽  
Vol 234 (2-3) ◽  
Author(s):  
Johann Peter Murmann ◽  
Jenny Korn ◽  
Hagen Worch
Keyword(s):  
Growth Rate ◽  
Mergers And Acquisitions ◽  
Growth Rates ◽  
Maximum Rate ◽  
High Growth ◽  
Organizational Structures ◽  
Sales Growth ◽  
Growth Firms ◽  
Simple Question ◽  
One Year

SummaryBuilding on recent research on dynamic, high-growth firms - so-called “gazelles” - this paper explores a simple question that is important in both theoretical and practical terms: What is the fastest rate at which firms can grow? Based on a sample of seven high-growth firms (Cisco, GM, IBM, Microsoft, Sears, Starbucks, and US Steel), we find that 162% is the maximum sales growth rate in any one year that an established company can grow without mergers and acquisitions, while the maximum rate of employee growth is approximately 115% even including some mergers and acquisitions. All of the companies in our sample attained a maximum sales growth rate of above 50%, with most hovering around 75%. Furthermore, the firms’ growth rates exhibit similar patterns. No company experienced its maximum sales growth rate toward the latter part of its history. Every company experienced its slowest employee growth rate after attaining its maximum employee growth rate, usually within a decade of one another. Most importantly, all firms show an average sales growth that exceeds the average employee growth. This finding is an indication that successful growing firms have a superior capability to continuously improve employment efficiency and adjust organizational structures to suit an increasing workforce.

Growth and phenotypic plasticity of two tropical tree species under low light availability

2020 ◽  
Author(s):  
Marúcia da Cunha Fagundes ◽  
Ândrea Carla Dalmolin ◽  
Luciana Santos Lobo ◽  
Ana Cristina Schilling ◽  
Martielly Santana dos Santos ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Growth Rates ◽  
Tree Species ◽  
Shade Tolerance ◽  
Carbon Allocation ◽  
Secondary Forest ◽  
Light Availability ◽  
Tropical Tree ◽  
Low Light ◽  
Tropical Tree Species

Abstract Aims Screening tree species in tropical rainforest according to their shade tolerance is important to efficiently manage the native trees of economic significance in secondary forest enrichment regimes. The objective of this study was to determine the whole-plant light compensation point (WPLCP) and compare the phenotypic plasticity in relation to growth and carbon allocation of Cariniana legalis and Gallesia integrifolia seedlings under low light availability. Methods Seedlings were cultivated for 77 days under conditions of five photosynthetically active radiation (PAR) (0.02, 1.1, 2.3, 4.5 and 5.9 mol photons m -2 day -1) in three replicates. Growth and carbon allocation variables were determined. Important Findings Growth rates of C. legalis were higher and lower than those of G. integrifolia under 1.1 and 5.9 mol photons m -2 day -1, respectively. The WPLCP differed significantly between the two species. In accordance with the criteria of the shade tolerance classification for these two tropical tree species, our results showed that C. legalis had lower WPLCP and phenotypic plasticity in terms of higher growth rates and greater shade tolerance than G. integrifolia. From a practical point of view, we demonstrated that the differential linkage between growth and changing PAR between the two species can become a useful tool for comparing and selecting tree species in forest enrichment projects.

GROWTH OF PIKE-PERCH SANDER LUCIOPERCA (L., 1758) (PERCIDAE) IN RESERVOIRS OF K. SATPAYEV’S CHANNEL

2018 ◽  
pp. 59-68
Author(s):  
Saule Zhangirovna Asylbekova ◽  
Kuanysh Baibulatovich Isbekov ◽  
Vladimir Nickolaevich Krainyuk
Keyword(s):  
Growth Rates ◽  
Growth Dynamics ◽  
High Growth ◽  
Water Bodies ◽  
Volga River ◽  
Trophic Resources ◽  
Pike Perch ◽  
The Amur River ◽  
Back Calculation ◽  
Abiotic And Biotic Factors

Pike-perch is an invader for the water basins of Central Kazakhstan. These species have stable self-reproductive populations in the regional waters. Back calculation method was used to investigate pike-perch growth rates in reservoirs of K. Satpayev’s channel. For comparison, the data from the other water bodies (Vyacheslavsky and Sherubay-Nurinsky water reservoirs) were used, as well as literature data. Pike-perch species from the investigated waters don’t show high growth rates. The populations from the reservoirs of K. Satpayev’s channel have quite similar growth rates with populations from the Amur river, from a number of reservoirs in the Volga river basin and from the reservoir in Spain. Sexual differences in growth have not been observed. Evaluating possible influence of various abiotic and biotic factors on the growth rate of pike-perch in the reservoirs of K. Satpayev’s channel was carried out. It has been stated that the availability of trophic resources cannot play a key role in growth dynamics because of their high abundance. Morphology of water bodies also does not play a role, as well as chromaticity, turbidity and other optical water indicators. It can be supposed that the main factor influencing growth of pike perch is the habitat’s temperature. This factor hardly ever approaches optimal values for the species in reservoirs of K. Satpaev’s channel. The possible influence of fishing selectivity on pike-perch growth rates was also evaluated. Currently, there has been imposed a moratorium on pike-perch catch. However, pike-perch is found in by-catches and in catches of amateur fishermen. It should be said that such seizures have an insignificant role in the dynamics of growth rates.

Restoration of floral diversity through plantations on abandoned agricultural land

2006 ◽  
Vol 36 (5) ◽  
pp. 1218-1235 ◽  
Author(s):  
Steven G Newmaster ◽  
F Wayne Bell ◽  
Christopher R Roosenboom ◽  
Heather A Cole ◽  
William D Towill
Keyword(s):  
Plant Diversity ◽  
Tree Species ◽  
Agricultural Land ◽  
Structural Diversity ◽  
Geographic Region ◽  
Natural Forests ◽  
Community Interactions ◽  
Long Term Study ◽  
Floral Diversity ◽  
The Impact

Plantations have been claimed to be "monocultures", or "biological deserts". We investigated these claims in the context of a long-term study on plant diversity within plantations with different indigenous tree species, spacings, and soil types that were compared with 410 native stands. Soil type had no influence on plantation species diversity or abundance, and wider spacing resulted in higher richness, lower woody plant abundance, slightly higher cover of herbaceous plants, and large increases in cryptogam cover. We also found a canopy species × spacing interaction effect, where the impact of increased spacing on understory vegetation was more pronounced in spruce than in pine plantations. The dynamic community interactions among species of feathermoss appear to be in response to the physical impediment from varying amounts of needle rain from the different tree species. High light interception and needle fall were negatively correlated with understory plant diversity, as was lack of structural diversity. This study indicates that through afforestation efforts agricultural lands can be restored to productive forests that can harbour nearly one-half of the plant species found in equivalent natural forests within the same geographic region in as little as 50 years. We recommend applying afforestation using indigenous conifer species as a first step towards rehabilitating conifer forests that have been converted to agriculture and subsequently abandoned.

Biology of Gadus morhua in Ogac Lake, a Landlocked Fiord on Baffin Island

1967 ◽  
Vol 24 (12) ◽  
pp. 2573-2594 ◽  
Author(s):  
David G. Patriquin
Keyword(s):  
Growth Rates ◽  
Gadus Morhua ◽  
Environmental Variability ◽  
Sea Urchins ◽  
High Growth ◽  
Baffin Island ◽  
Meristic Characters ◽  
Large Size ◽  
Fin Ray ◽  
High Length

Gadus morhua L. occurs in Ogac Lake, a salt, meromictic lake on Baffin Island that receives influxes of seawater only during the highest summer tides. Cod of the order of 10,000 of lengths 25 cm and greater and 500 of lengths greater than 60 cm were present. The size ranges for various ages far exceeded those of oceanic populations. Feeding conditions were poor, and sea urchins predominated in the diet. Large cod (greater than 50 cm) were highly cannibalistic, and it was estimated that they consume of the order of 3500 fish of 20–40 cm annually. Maturation occurred at the unusually large size of 85 cm in females, and at about 65 cm in males. Apparently many of the cod never reach these sizes. Spawning was from late May to early July in 1962, and initiation of spawning appeared to be related to light. The hatching of cod larvae coincided with the appearance of the nauplii of the dominant copepod in the lake. Egg size was highly variable and exhibited a curious bimodalism. Variation in vertebral and fin-ray counts was slight in spite of high environmental variability, and thus appears largely genetically controlled. Possibly the first inhabitants came from Greenland stocks, which have high growth rates similar to the faster growing cod in the lake, and similar high length at maturity. Meristic characters also suggest affinity with Greenland rather than Labrador cod. The hydrography of the area and the possibilities of larval drift or adult migration into the lake are discussed. Cannibalism must exert continuing selection for high growth rates, but very poor feeding conditions and hierarchial dominance effects probably prevent general attainment of high growth rates.

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