Sandfly stratification on tree buttresses in a Costa Rican tropical rainforest

1994 ◽  
Vol 10 (1) ◽  
pp. 87-101 ◽  
Author(s):  
Jane Memmott ◽  
Stephen L. Sutton
Keyword(s):  
Tropical Rainforest ◽  
Ground Level ◽  
Costa Rican ◽  
Vertical Stratification ◽  
Experimental Conditions ◽  
Resting Sites ◽  
Phlebotomine Sandflies

ABSTRACTIn humid forests tree buttresses and tree trunks are used as diurnal resting sites by phlebotomine sandflies (Diptera: Psychodidae). When several species are present on the same buttress, the sandfly species are spatially segregated resulting in a pattern of vertical stratification on the buttress within 100 cm of ground level. A change in the distribution of one species induces a change in the distribution of an adjacent species. This is demonstrated under both natural and experimental conditions. Observations of sandflies at dawn and dusk have revealed that the buttress is used as a swarming site; this behaviour provides our favoured explanation for the patterns of vertical stratification on tree buttresses.

On the vertical distribution of Phlebotomine sandflies (Dipt., Psychodidae) in British Honduras (Belize)

1970 ◽  
Vol 59 (4) ◽  
pp. 637-646 ◽  
Author(s):  
Paul Williams
Keyword(s):  
Ground Level ◽  
Insect Host ◽  
Leishmania Mexicana ◽  
Light Traps ◽  
Principal Vector ◽  
New Information ◽  
Phlebotomine Sandflies ◽  
British Honduras ◽  
The Vertical Distribution ◽  
Blood Meals

Phlebotomine sandflies were collected simultaneously at ground level, 25 ft and 40 ft in an area of medium bush in British Honduras (Belize).Flies were captured on human bait, with rat-baited oil-traps and with miniature light-traps, and some resting individuals were collected at each level. One species of Brumptomyia França and 18 of Lutzomyia França & Parrot were obtained. Brief notes on some of these species are given.Miniature light-traps provided the widest range of species, were the most satisfactory means for collecting Brumptomyia, L. steatopyga (Fairchild & Hertig) and L. carpenteri (Fairchild & Hertig), and yielded new information on the flight activities of L. deleoni (Fairchild & Hertig) and L. panamensis (Shannon).Most species collected were found to be predominantly arboreal in habit, L. permira (Fairchild & Hertig) and Lutzomyia sp. P being almost exclusively so. Some species (L. panamensis, possibly L. geniculata (Mangabeira) and L. bispinosa (Fairchild & Hertig)) live amongst the foliage but descend to the forest floor to seek blood-meals. A few species (L. steatopyga, L. deleoni and L. olmeca (Vargas & Díaz Nájera)) are active mainly near the ground, though the occasional specimen may be carried much higher.L. olmeca is the principal vector of rodent leishmaniasis in British Honduras. In the present study, no evidence was obtained to incriminate any other species of Phlebotomine as an insect host for Leishmania mexicana, and the mode of transmission of the parasite to man remains obscure.

Does resource availability govern vertical stratification of small mammals in an Australian lowland tropical rainforest?

2006 ◽  
Vol 33 (7) ◽  
pp. 571 ◽  
Author(s):  
R. Rader ◽  
A. Krockenberger
Keyword(s):  
Resource Availability ◽  
Tropical Rainforest ◽  
Vertical Stratification ◽  
Resource Abundance ◽  
Canopy Trees ◽  
Small Mammal Community ◽  
Castanospermum Australe ◽  
Mammal Community ◽  
Mammal Assemblages ◽  
Access To Food

Mammal assemblages of rainforest communities are commonly vertically stratified. This can be associated with competition for, or access to, resources in the upper canopy layers of the forest. This study investigated the extent of vertical stratification in a small mammal community of a tropical rainforest and whether any structure was related to resource abundance. The mammal community was vertically stratified, with Pogonomys mollipilosus and Cercartetus caudatus found only in the upper canopy layers and Rattus sp., Isoodon macrourus and Antechinus flavipes rubeculus on the ground and in the understorey layer. Melomys cervinipes and Uromys caudimaculatus were found at all four height layers. Total rodent captures were not significantly correlated with the abundance of fruit and flower resources, but arboreal captures of M. cervinipes and P. mollipilosus were correlated with the number of individual canopy trees of four prominent flower- and fruit-yielding species: Syzigium sayeri, Acmena graveolens, Argyrodendron perelatum and Castanospermum australe. We suggest that arboreal behaviour in these rodents serves to provide the advantages of first access to food resources, the availability of abundant resources in the canopy, and, ultimately, reduced competition in the upper strata.

scholarly journals Secondary organic aerosol formation from photooxidation of furan: effects of NOx and humidity

2019 ◽  
Author(s):  
Xiaotong Jiang ◽  
Narcisse T. Tsona ◽  
Long Jia ◽  
Shijie Liu ◽  
Hailiang Zhang ◽  
...  
Keyword(s):  
Ultrafine Particles ◽  
Mass Concentration ◽  
Secondary Organic Aerosol ◽  
Ground Level ◽  
Organic Aerosol ◽  
Liquid Water Content ◽  
Aerosol Formation ◽  
Scanning Mobility Particle Sizer ◽  
Experimental Conditions ◽  
Significant Difference

Abstract. Atmospheric furan is a primary and secondary pollutant in the atmosphere, and its emission contributes to the formation of ultrafine particles and ground-level ozone. We investigate the effects of NOx level and humidity on the formation of secondary organic aerosol (SOA) generated from the photooxidation of furan in the presence of NaCl seed particles. The particle mass concentration and size distribution were determined with a scanning mobility particle sizer (SMPS). SOA mass concentration and yield were determined under different NOx and humidity levels. A significant difference is observed both in the SOA mass concentration and SOA yield variation with the initial experimental conditions. Six organic products were identified in the collected SOA by electrospray ionization exactive orbitrap mass spectrometry (ESI-Exactive-Orbitrap MS). The –COOH, –OH, –C=O and NO2 functional groups were assigned in the FTIR spectra and used as the indicator for the mechanism inference. In addition, O3 formation was also observed during the furan-NOx-NaCl photooxidation. Based on the MS analysis, the reaction mechanism was proposed to follow the RO2+NO pathway. A significant amount of carbonyl-rich products was detected in the SOA products from the photooxidation of furan. The SOA mass concentration and yield increase with increasing humidity, because higher aerosol liquid water content brings more aqueous phase reactions. The present study demonstrates the effect of NOx and humidity on SOA formation during the furan-NOx-NaCl photooxidation. Furthermore, the results illustrate the importance of studying SOA formation over a comprehensive range of environmental conditions. Only such evaluations can induce meaningful SOA mechanisms to be implemented in air quality models.

scholarly journals In situ measurements of isoprene and monoterpenes within a south-east Asian tropical rainforest

2011 ◽  
Vol 11 (14) ◽  
pp. 6971-6984 ◽  
Author(s):  
C. E. Jones ◽  
J. R. Hopkins ◽  
A. C. Lewis
Keyword(s):  
Tropical Rainforest ◽  
East Asian ◽  
Ground Level ◽  
Ambient Air ◽  
Tropical Rainforests ◽  
Light Conditions ◽  
Mixing Ratios ◽  
Volatile Carbon ◽  
Malaysian Borneo

Abstract. Biogenic volatile organic compounds (BVOCs) emitted from tropical rainforests comprise a substantial fraction of global atmospheric VOC emissions, however there are only relatively limited measurements of these species in tropical rainforest regions. We present observations of isoprene, α-pinene, camphene, Δ-3-carene, γ-terpinene and limonene, as well as oxygenated VOCs (OVOCs) of biogenic origin such as methacrolein, in ambient air above a tropical rainforest in Malaysian Borneo during the Oxidant and Particle Photochemical Processes above a south-east Asian tropical rainforest (OP3) project in 2008. Daytime composition was dominated by isoprene, with an average mixing ratio of the order of ~1 ppb. γ-terpinene, limonene and camphene were the most abundant monoterpenes, with average daytime mixing ratios of 102, 71 and 66 ppt respectively, and with an average monoterpene toisoprene ratio of 0.3 during sunlit hours, compared to 2.0 at night. Limonene and camphene abundances were seen to be related to both temperature and light conditions. In contrast, γ-terpinene emission continued into the late afternoon/evening, under relatively low temperature and light conditions. The contributions of isoprene, monoterpenes and other classes of VOC to the volatile carbon budget and OH reactivity have been summarised for this rainforest location. We observe good agreement between surface and aircraft measurements of boundary layer isoprene and methacrolein above the natural rainforest, suggesting that the ground-level observations are broadly representative of isoprene emissions from this region.

Photosynthetically Active Radiation Environment, Patch Dynamics and Architecture in a Tropical Rainforest in Sumatra

1988 ◽  
Vol 15 (2) ◽  
pp. 327 ◽  
Author(s):  
EF Torquebiau
Keyword(s):  
Photosynthetically Active Radiation ◽  
Forest Dynamics ◽  
Tropical Rainforest ◽  
Lower Layer ◽  
Ground Level ◽  
Radiation Environment ◽  
Horizontal Gradient ◽  
Active Radiation ◽  
Mature Forest ◽  
Treefall Gap

The photosynthetically active radiation (PAR) environments of three sites within a tropical rainforest in Sumatra were characterised. The sites and sensor locations were chosen according to a previous study of forest dynamics based on forest mosaic maps and an analysis of forest architecture by means of detailed profile diagrams. Two sites were located in mature forest patches: one showed a layered architecture while the other had a continuous vertical distribution of foliage. A third site represented a 320 m� treefall gap. Vertical gradients of PAR from above canopy to ground level were studied in the mature forest zones, while a horizontal gradient of PAR at ground level was studied across a gap-mature forest boundary. Daily total PAR at ground level in the mature forest sites was 0.78% and 0.57% of incident radiation above the forest. The decrease of radiation from above canopy downwards was strikingly different between the sites: the layered site showed a 'PAR inversion' between successive layers, the amount of radiation under a given layer being less than at the top of the next lower layer. The non-layered site did not show such an inversion. The treefall gap radiation received was approximately 20% of the radiation recorded above the canopy. The spatial distribution of PAR in the forest is highly variable but can be usefully analysed against a framework of forest dynamics and architecture. Temporal distribution of PAR is also highly variable, and both distributions need to be analysed to understand photosynthetic responses and growth rates of rainforest species.

Tropical nematode diversity: vertical stratification of nematode communities in a Costa Rican humid lowland rainforest

2009 ◽  
Vol 18 (5) ◽  
pp. 985-996 ◽  
Author(s):  
T. O. POWERS ◽  
D. A. NEHER ◽  
P. MULLIN ◽  
A. ESQUIVEL ◽  
R. M. GIBLIN-DAVIS ◽  
...  
Keyword(s):  
Costa Rican ◽  
Vertical Stratification ◽  
Nematode Communities ◽  
Nematode Diversity ◽  
Lowland Rainforest

Observations on the peri-domestic breeding behaviour and resting sites of Glossina tachinoides Westw. near Nsukka, East Central State, Nigeria

1970 ◽  
Vol 59 (4) ◽  
pp. 585-593 ◽  
Author(s):  
D. A. T. Baldry
Keyword(s):  
Ground Level ◽  
Tsetse Fly ◽  
Central State ◽  
Night Time ◽  
East Central ◽  
Breeding Sites ◽  
Resting Sites ◽  
Moisture Conditions ◽  
Emulsion Concentrate ◽  
Domestic Breeding

In 1964–65, breeding sites of the tsetse fly G. tachinoides Westw. near Nsukka in south-eastern Nigeria were found in peri-domestic situations (particularly beneath stacked coco-yam tubers and at the base of fences of pig enclosures) and in adjacent farmland (particularly beneath banana and coco-yam plants, under Lantana camara, at the base of farmland fences and around derelict farm buildings). Between them, these sites provide moisture conditions suitable for year-round breeding of G. tachinoides and are not exposed to unsuitably high temperatures (>90°F) for long periods. The night-time resting sites of G. tachinoides in three villages five miles east of Nsukka were sought between May and November 1966 using ordinary torchlight. The most popular resting-sites were dried fronds of oil and coconut palms used for fencing pig enclosures, but a few flies also rested on man-made objects in the villages and on vegetation nearby. Most flies were resting less than two feet above ground level. Day-time observations confirmed the night-time findings. G. tachinoides could probably be controlled, if not eradicated, in the Nsukka area by two applications, a fortnight apart, of DDT emulsion concentrate to pig enclosure fences and pig styes up to a height of 2–3 ft during March–May when the fly population is most concentrated around confined pigs.

scholarly journals Studies of an artificially generated electrode effect at ground level

1996 ◽  
Vol 14 (10) ◽  
pp. 1095-1101 ◽  
Author(s):  
E. A. Mareev ◽  
S. Israelsson ◽  
E. Knudsen ◽  
A. V. Kalinin ◽  
M. M. Novozhenov
Keyword(s):  
Wind Speed ◽  
Charge Density ◽  
Space Charge ◽  
Turbulent Mixing ◽  
Ground Surface ◽  
Ground Level ◽  
Space Charge Density ◽  
Experimental Conditions ◽  
Electrical Field Strength ◽  
Electrode Effect

Abstract. The outdoor experiments, using a metallic grid above the ground surface, have yielded well-defined vertical profiles of the space-charge density. The profiles showed strong evidence for the existence of an electrode effect, which could be named the artificial electrode effect and can serve as a very useful and well-controlled model for the study of atmospheric electric processes in the atmospheric surface layer. The build-up or break-down of an electrode-effect layer occurred in a time of the order of 10 s under the experimental conditions realized. The artificially generated electrode effect is dependent on the electrical field strength supplied, wind speed, turbulent mixing and ion mobilities. Wind speed and ion mobility seem to be the dominant factors, defining space-charge density profiles. A theoretical model for the artificial electrode effect has been developed, taking into account turbulent mixing of charged particles in the air flow with the logarithmic profile of the wind velocity. The numerical analysis of the boundary value problem for the two-dimensional equations for the light ion concentrations has been performed. The model presented shows a qualitative agreement of calculated space-charge profiles with measured ones, and explains the dependence of the artificial electrode effect on the dominant control parameters. The limiting conditions for the developed theory are discussed.

scholarly journals Using the Nitrification Inhibitor Nitrapyrin in Dairy Farm Effluents Does Not Improve Yield-Scaled Nitrous Oxide and Ammonia Emissions but Reduces Methane Flux

2021 ◽  
Vol 5 ◽  
Author(s):  
Ana Gabriela Pérez-Castillo ◽  
Jimmy Arrieta-Méndez ◽  
Jorge Alberto Elizondo-Salazar ◽  
Mayela Monge-Muñoz ◽  
Mohammad Zaman ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Block Design ◽  
Nitrification Inhibitor ◽  
Dairy Farm ◽  
Previous Treatment ◽  
Costa Rican ◽  
Experimental Conditions ◽  
N Losses ◽  
Total N ◽  
Significant Difference

The application of dairy farm effluents (DFE) without previous treatment in paddocks was intensified due to the approval of this practice in Costa Rican legislation since 2012. Applying DFE instead of synthetic N fertilizer in grasslands is an opportunity to reach a circular economy; however, this practice increases the risk of emissions of nitrous oxide (N2O), methane (CH4), and ammonia (NH3), which contribute to global warming. A field experiment was carried out using a permanent grassland (90% Star grass and 10% Kikuyo grass) to simultaneously assess the effect of nitrapyrin on yield-scaled emissions of NH3, CH4, and N2O. The experiment lasted for 5 months in 2017, based on a randomized complete block design, including three treatments of control (CK) without N application, surface application of DFE with nitrapyrin (SNI), and without nitrapyrin (S). Total N applied was 149 ± 12 kg N ha−1 for both S and SNI treatments split into five applications. CH4 emissions from S, SNI, and CK showed a high temporal variation. Daily fluxes of CH4 from SNI were significantly lower than those of S in August (P < 0.05). Cumulative emissions of CH4, the majority produced in the soil, ranged from 4 to 168 g ha−1 for S, and from −13 to 88 g ha−1 for SNI. The ratio between the N2O cumulative emissions and the N applied as DFE were 1.6 ± 0.5 and 1.7 ± 0.2% for S and SNI, respectively. NH3 volatilization potential was very low (i.e., 0.6 ± 0.2% of the N applied). Under the prevailing experimental conditions, no significant difference between yield-scaled NH3 and N2O emissions were found between S and SNI, suggesting that nitrapyrin may not be a viable mitigation option for gaseous N losses from DFE application in Costa Rican grasslands in rainy season.

scholarly journals Five years of land surface phenology in a large-scale flooding and draining manipulation in a coastal Arctic ecosystem

2017 ◽  
Author(s):  
Santonu Goswami ◽  
John A. Gamon ◽  
Sergio Vargas ◽  
Craig E. Tweedie
Keyword(s):  
Surface Water ◽  
Land Surface ◽  
Large Scale ◽  
Ground Level ◽  
The Arctic ◽  
Surface Hydrology ◽  
Experimental Conditions ◽  
Land Surface Phenology ◽  
Growing Period ◽  
Near Ir

AbstractThis study was motivated by the knowledge gap for observing the complex interplay between surface hydrology and plant phenology in arctic landscapes and was conducted as part of a large scale, multi investigator flooding and draining experiment near Barrow, Alaska (71°17’01” N, 156°35’48” W) during 2005 - 2009. Hyperspectral reflectance data were collected in the visible to near IR region of the spectrum using a robotic tram system that operated along a 300m transects during the snow free growing period between June and August, 2005-09. Interannual patterns of land-surface phenology (NDVI) unexpectedly lacked marked differences under experimental conditions. Measurement of NDVI was, however, compromised for presence of surface water. Land-surface phenology and surface water was negatively correlated, which held when scaled to a 2km by 2km MODIS subset of the study area. This result suggested that published findings of ‘greening of the Arctic’ may relate to a ‘drying of the Arctic’ i.e. reduced surface water in vegetated high-latitude landscapes where surface water is close to ground level.

Sign in / Sign up

Export Citation Format

Share Document