scholarly journals Effects of nitrogen and phosphorus fertilization in a lowland evergreen rainforest

1999 ◽  
Vol 354 (1391) ◽  
pp. 1825-1829 ◽  
Author(s):  
E. Mirmanto ◽  
J. Proctor ◽  
J. Green ◽  
L. Nagy ◽  
Suriantata
Keyword(s):  
Nutrient Addition ◽  
Phosphorus Fertilization ◽  
Nitrogen And Phosphorus ◽  
Central Kalimantan ◽  
Dipterocarp Forest ◽  
Separate Treatment ◽  
Lowland Dipterocarp Forest ◽  
The Difference ◽  
Set Up ◽  
Nutrient Addition Experiment

A nutrient addition experiment was set up in August 1993 in a species–rich primary lowland dipterocarp forest in Barito Ulu, Central Kalimantan, Indonesia. The following treatments were applied: control, +N, +P and +NP. There were five blocks of four 50 m times 50 m plots with a separate treatment for each plot. Fine litterfall was measured on all the plots from l May 1994 for 12 months. Litterfall mass and phosphorus concentrations were significantly higher in all the fertilizer treatments compared with the controls. All trees (greater than or equal to 10 cm dbh) were measured in August 1993 and in August 1998, and there was no significant girth increment response to fertilization in dipterocarps or non–dipterocarps. Dipterocarps of the red meranti group showed a doubling of girth increment in the +NP treatment, however, the difference from the control fell short of significance.

The influence of gibbon primary seed shadows on post-dispersal seed fate in a lowland dipterocarp forest in Central Borneo

2005 ◽  
Vol 21 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Kim R. McConkey
Keyword(s):  
Seed Fate ◽  
Central Kalimantan ◽  
Fruit Abundance ◽  
Seed Shadow ◽  
Dipterocarp Forest ◽  
Lowland Dipterocarp Forest ◽  
Seed Shadows ◽  
Insect Predation ◽  
Dispersal Events

The natural seed shadow created by gibbons (Hylobates mulleri×agilis) in Central Kalimantan, Indonesia, was monitored over 11 mo to discern the role of gibbons and post-dispersal events in the spatial pattern of seed germination. Variability in the content and distribution of 183 scats was used to determine which, if any, scat characteristics influenced seed fate. Nine scat characters were evaluated: (1) seed number; (2) number of seed species per scat; (3) scat weight; (4) seed load; (5) rainfall; (6) scat density; (7) distance to nearest fruiting tree; (8) ripe fig abundance; (9) non-fig fruit abundance. More than 99% of monitored seeds were killed, removed, or had germinated during the monitoring period. Vertebrates killed or removed most seeds (86%) and the probability of them moving seeds was highly dependent on non-fig fruit abundance at the time of deposition; factors (2), (6) and (7) also influenced seed removal/predation by vertebrates, depending on whether seeds were deposited in peak or non-peak times of consumption. Insect predation (2% of seeds) occurred mainly in scats that were deposited in months of high ripe fig abundance, while the actual chance of a seed germinating (11% of seeds) was influenced by non-fig fruit abundance at time of deposition and number of species in the original scat. The gibbon-generated seed shadow was profoundly altered by post-dispersal events and variation in the characteristics of the shadow had little lasting impact on the probability of seeds germinating.

scholarly journals Nitrogen and phosphorus fertilization consistently favor pathogenic over mutualistic fungi in grassland soils

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ylva Lekberg ◽  
Carlos A. Arnillas ◽  
Elizabeth T. Borer ◽  
Lorinda S. Bullington ◽  
Noah Fierer ◽  
...  
Keyword(s):  
Plant Communities ◽  
Structural Equation ◽  
Fungal Pathogens ◽  
Structural Equation Models ◽  
Nutrient Addition ◽  
Ecosystem Functions ◽  
Phosphorus Fertilization ◽  
Community Characteristics ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Addition

AbstractEcosystems across the globe receive elevated inputs of nutrients, but the consequences of this for soil fungal guilds that mediate key ecosystem functions remain unclear. We find that nitrogen and phosphorus addition to 25 grasslands distributed across four continents promotes the relative abundance of fungal pathogens, suppresses mutualists, but does not affect saprotrophs. Structural equation models suggest that responses are often indirect and primarily mediated by nutrient-induced shifts in plant communities. Nutrient addition also reduces co-occurrences within and among fungal guilds, which could have important consequences for belowground interactions. Focusing only on plots that received no nutrient addition, soil properties influence pathogen abundance globally, whereas plant community characteristics influence mutualists, and climate influence saprotrophs. We show consistent, guild-level responses that enhance our ability to predict shifts in soil function related to anthropogenic eutrophication, which can have longer-term consequences for plant communities.

Local wind damage in Barito Ulu, Central Kalimantan: a rare but essential event in a lowland dipterocarp forest?

2001 ◽  
Vol 17 (3) ◽  
pp. 473-475 ◽  
Author(s):  
J. PROCTOR ◽  
F.Q. BREARLEY ◽  
H. DUNLOP ◽  
K. PROCTOR ◽  
SUPRAMONO ◽  
...  
Keyword(s):  
Large Scale ◽  
Peninsular Malaysia ◽  
Forest Damage ◽  
Local Wind ◽  
Central Kalimantan ◽  
Dipterocarp Forest ◽  
North East ◽  
Detailed Assessment ◽  
Lowland Dipterocarp Forest ◽  
Trail System

The importance of disturbances for the dynamics of tropical forests has been described by Whitmore & Burslem (1998). Among the phenomena which they classify as large scale disturbances are those caused by wind. The most extensive of these occur within the hurricane (cyclone) belt (10-20° from the equator) but outside this belt large blowdowns of trees are known to occur, perhaps most spectacularly in the Brazilian Amazon (Nelson et al. 1994). There is evidence that rare wind storms influence the dipterocarp rain forests of Peninsular Malaysia, 2-6°N. One famous storm in November 1880 which devastated hundreds of square kilometres of forests in Kelantan, north-east Malaya, was probably an aberrant cyclone (Wyatt-Smith 1954). Smaller windstorms which have blown down several hectares of forests have been reported from Malaysia including Borneo (Ashton 1993) but their frequency and extent have not been well documented (Whitmore & Burslem 1998). At Barito Ulu, Central Kalimantan, one such storm occurred recently and the fortuitous combination of a well patrolled trail system and the localization of the storm has allowed a detailed assessment of the forest damage.

Decay classes of coarse woody debris in a lowland Dipterocarp forest: implications for volume, density, and carbon estimates

Biotropica ◽  
2021 ◽  
Author(s):  
Ekaterina Shorohova ◽  
Ekaterina Kapitsa ◽  
Andrey Kuznetsov ◽  
Svetlana Kuznetsova ◽  
Valentin Lopes de Gerenuy ◽  
...  
Keyword(s):  
Coarse Woody Debris ◽  
Woody Debris ◽  
Volume Density ◽  
Dipterocarp Forest ◽  
Lowland Dipterocarp Forest

Experimental Investigation into Driver Behavior along Curved and Parallel Diverging Terminals of Exit Interchange Ramps

2021 ◽  
pp. 036119812199742
Author(s):  
Alberto Portera ◽  
Marco Bassani
Keyword(s):  
Design Stage ◽  
Lane Change ◽  
Age And Gender ◽  
Traffic Conditions ◽  
Current Design ◽  
The Difference ◽  
Safety Countermeasures ◽  
And Gender ◽  
Set Up ◽  
Curve Radius

Current design manuals provide guidance on how to design exit ramps to facilitate driving operations and minimize the incidence of crashes. They also suggest that interchanges should be built along straight roadway sections. These criteria may prove ineffective in situations where there is no alternative to terminals being located along curved motorway segments. The paper investigates driving behavior along parallel deceleration curved terminals, with attention paid to the difference in impact between terminals having a curvature which is the same sign as the motorway segment (i.e., continue design), and those having an opposite curvature (i.e., reverse design). A driving simulation study was set up to collect longitudinal and transversal driver behavioral data in response to experimental factor variations. Forty-eight drivers were stratified on the basis of age and gender, and asked to drive along three randomly assigned circuits with off-ramps obtained by combining experimental factors such as motorway mainline curve radius (2 values), terminal length (3), curve direction (2), and traffic conditions (2). The motorway radius was found to be significant for drivers’ preferred speed when approaching the terminal. Terminal length and traffic volume do not have a significant impact on either longitudinal or transversal driver outputs. However, the effect of curve direction was found to be significant, notably for reverse terminals which do not compel drivers to select appropriate speeds and lane change positions. This terminal type can give rise to critical driving situations that should be considered at the design stage to facilitate the adoption of appropriate safety countermeasures.

Pump Performance Improvement by Restraining Back Flow in Screw-Type Centrifugal Pump

2005 ◽  
Vol 127 (4) ◽  
pp. 755-762 ◽  
Author(s):  
Yasushi Tatebayashi ◽  
Kazuhiro Tanaka ◽  
Toshio Kobayashi
Keyword(s):  
Pressure Fluctuations ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Simple Method ◽  
Back Flow ◽  
Pump Performance ◽  
Impeller Outlet ◽  
Pump Head ◽  
The Difference ◽  
Set Up

The authors have been investigating the various characteristics of screw-type centrifugal pumps, such as pressure fluctuations in impellers, flow patterns in volute casings, and pump performance in air-water two-phase flow conditions. During these investigations, numerical results of our investigations made it clear that three back flow regions existed in this type of pump. Among these, the back flow from the volute casing toward the impeller outlet was the most influential on the pump performance. Thus the most important factor to achieve higher pump performance was to reduce the influence of this back flow. One simple method was proposed to obtain the restraint of back flow and so as to improve the pump performance. This method was to set up a ringlike wall at the suction cover casing between the impeller outlet and the volute casing. Its effects on the flow pattern and the pump performance have been discussed and clarified to compare the calculated results with experimental results done under two conditions, namely, one with and one without this ring-type wall. The influence of wall’s height on the pump head was investigated by numerical simulations. In addition, the difference due to the wall’s effect was clarified to compare its effects on two kinds of volute casing. From the results obtained it can be said that restraining the back flow of such pumps was very important to achieve higher pump performance. Furthermore, another method was suggested to restrain back flow effectively. This method was to attach a wall at the trailing edge of impeller. This method was very useful for avoiding the congestion of solids because this wall was smaller than that used in the first method. The influence of these factors on the pump performance was also discussed by comparing simulated calculations with actual experiments.

The consequences of selective logging for Bornean lowland forest birds

1992 ◽  
Vol 335 (1275) ◽  
pp. 443-457 ◽  
Keyword(s):  
Population Dynamics ◽  
Bird Species ◽  
Selective Logging ◽  
Forest Birds ◽  
Primary Forest ◽  
Bird Conservation ◽  
Lowland Forest ◽  
Dipterocarp Forest ◽  
Logged Forest ◽  
Lowland Dipterocarp Forest

In lowland dipterocarp forest in Sabah, Malaysia, most primary forest bird species were present in areas selectively logged eight years previously. However, certain taxa, notably flycatchers, woodpeckers, trogons and wren-babblers, became comparatively rare. In contrast, nectarivorous and opportunistic frugivorous species were significantly more abundant. Few species appeared to change foraging height, but netting rates suggest that the activity of some species had increased, or that some birds ranged over larger areas after logging. Although there is still much to be learned about the survival of birds in logged forest, large areas of this habitat are important for bird conservation. However, the susceptibility of logged forest to fire, and our present incomplete understanding of bird behaviour and population dynamics in logged forests mean that they should not be considered by conservationists as alternatives to reserves of primary forest.

scholarly journals Effects of nitrogen and phosphorus on the abundance and cell size of planktonic nanoflagellate communities

2013 ◽  
Vol 24 (4) ◽  
pp. 427-437
Author(s):  
Danielle Goeldner Pereira ◽  
Fábio Amodêo Lansac-Tôha ◽  
Gustavo Mayer Pauleto ◽  
Luis Mauricio Bini ◽  
Luiz Felipe Machado Velho
Keyword(s):  
Cell Size ◽  
Nutrient Enrichment ◽  
Nitrogen Addition ◽  
Nutrient Addition ◽  
Heterotrophic Nanoflagellates ◽  
Nitrogen And Phosphorus ◽  
Tropical Reservoir ◽  
Pigmented Nanoflagellates ◽  
Density And Biomass ◽  
Nitrogen And Phosphorus Enrichment

AIM: We experimentally investigated the effects of nutrients (Nitrogen and Phosphorus) enrichment on the density, biomass, and cell size of pigmented and heterotrophic plankton nanoflagellates communities. METHODS: The experiment was done in mesocosms in a tropical reservoir during a 19-day period. Four different treatments were carried out: Control (non-nutrient addition - C), phosphorus additions (P), nitrogen addition (N) and phosphorus + nitrogen addition (N + P). Each treatment was performed in triplicate, sorted randomly, thus giving a total of 12 experimental carboys, which were placed transversely in the middle of the reservoir. RESULTS: In general, pigmented and heterotrophic nanoflagellates fractions responded to nutrient addition, increasing densities and biomass values at the fertilized treatments. Opposed to expected, enriched treatments resulted in a slight decrease in mean cell size of the pigmented fraction. Moreover, in nutrient-rich treatments, pigmented nanoflagellates had higher relative abundance than in the control. CONCLUSIONS: Our results indicate that: i) the density and biomass of nanoflagellates responded to the nutrient enrichment, mainly when N and P were added together; ii) the pigmented and heterotrophic fractions showed distinct time responses to fertilization; iii) the growth of nanoflagellate community seems to be co-limited by N and P; iv) the nutrient enrichment led to a greater pigmented than heterotrophic fraction contribution; and v) among the analyzed variables, nanoflagellate densities seem to be more sensitive to changes in nutrient availability than biomass or mean cell size.

Telemedicine in pediatric and perinatal cardiology: Economic evaluation of a service in English hospitals

2007 ◽  
Vol 23 (1) ◽  
pp. 116-125 ◽  
Author(s):  
Robin Dowie ◽  
Hema Mistry ◽  
Tracey A. Young ◽  
Gwyn C. Weatherburn ◽  
Helena M. Gardiner ◽  
...  
Keyword(s):  
Older Children ◽  
Telemedicine Service ◽  
Clinical Events ◽  
District Hospitals ◽  
Nonsignificant Difference ◽  
Patient Groups ◽  
Women And Children ◽  
The Difference ◽  
Set Up ◽  
Mean Cost

Objectives:Pediatric cardiology has an expanding role in fetal and pediatric screening. The aims of this study were to observe how district hospitals use a pediatric telecardiology service, and to compare the costs and outcomes of patients referred to specialists by means of this service or conventionally.Methods:A telemedicine service was set up between a pediatric cardiac center in London and four district hospitals for referrals of second trimester women, newborn babies, and older children. Clinicians in each hospital decided on the role for their service. Clinical events were audited prospectively and costed, and patient surveys were conducted.Results:The hospitals differed in their selection of patient groups for the service. In all, 117 telemedicine patients were compared with 387 patients seen in London or in outreach clinics. Patients selected for telemedicine were generally healthier. For all patients, the mean cost for the initial consultation was £411 for tele-referrals and £277 for conventional referrals, a nonsignificant difference. Teleconsultations for women and children were significantly more expensive because of technology costs, whereas for babies, ambulance transfers were much more costly. After 6-months follow-up, the difference between referral methods for all patients was nonsignificant (telemedicine, £3,350; conventional referrals, £2,172), and nonsignificant within the patient groups.Conclusions:Telemedicine was perceived by cardiologists, district clinicians, and families as reliable and efficient. The equivocal 6-month cost results indicate that investment in the technology is warranted to enhance pediatric and perinatal cardiology services.

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