scholarly journals Forest Canopy Can Efficiently Filter Trace Metals from Deposited Precipitation in a Sub-Alpine Spruce Plantation

2019 ◽  
Author(s):  
Siyi Tan ◽  
Hairong Zhao ◽  
Wanqin Yang ◽  
Bo Tan ◽  
Kai Yue ◽  
...  
Keyword(s):  
Trace Metals ◽  
Atmospheric Circulation ◽  
Human Disturbance ◽  
Rainy Season ◽  
Forest Canopy ◽  
Observational Period ◽  
Alpine Forest ◽  
Filter Effect ◽  
Closed Canopy ◽  
One Year

Trace metals can enter some natural regions with low human disturbance from atmospheric circulation, but little information is available regarding how the canopy can retained trace metals. Therefore, a representative sub-alpine spruce plantation was selected to investigate the net throughfall fluxes of eight trace metals (Fe, Mn, Cu, Zn, Al, Pb, Cd and Cr) of closed canopy and gap-edge canopy from August 2015 to July 2016. Over a one-year observational period, the annual fluxes of Al, Zn, Fe, Mn, Cu, Cd, Cr and Pb were 7.29 kg·ha-1, 2.30 kg·ha-1, 7.02 kg·ha-1, 0.16 kg·ha-1, 0.19 kg·ha-1, 0.06 kg·ha-1, 0.56 kg·ha-1 and 0.24 kg·ha-1, respectively, in the deposited precipitation. The annual net throughfall fluxes of these trace metals were 1.73 kg·ha-1, 0.9 kg·ha-1, 1.68kg·ha-1, -0.032 kg·ha-1, 0.04 kg·ha-1, 0.018 kg·ha-1, 0.093 kg·ha-1 and 0.087kg·ha-1, respectively, in the gap-edge canopy and -1.6 kg·ha-1, 1.13 kg·ha-1, 1.65 kg·ha-1, -0.10 kg·ha-1, 0.05 kg·ha-1, 0.03 kg·ha-1, 0.26 kg·ha-1 and 0.15 kg·ha-1, respectively, in the closed canopy. The closed canopy displayed a greater filter effect on the trace metals from precipitation than did the gap-edge canopy in the sub-alpine forest. In the rainy season, the net filtering ratio of trace metals ranged from -66%-89% in the closed canopy and from -52% to 25% in the gap-edge canopy. However, the net filtering ratio of all trace metals was greater than 50% in the closed canopy in the snowy season. Therefore, the results suggested that the most trace metals moving through the forest canopy are taken up rather than by rainfall leaching; moreover, the closed canopy can efficiently take up trace metals in the snowy season.

scholarly journals Forest Canopy Can Efficiently Filter Trace Metals in Deposited Precipitation in a Subalpine Spruce Plantation

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 318 ◽  
Author(s):  
Siyi Tan ◽  
Hairong Zhao ◽  
Wanqin Yang ◽  
Bo Tan ◽  
Kai Yue ◽  
...  
Keyword(s):  
Trace Metals ◽  
Human Disturbance ◽  
Forest Canopy ◽  
Subalpine Forest ◽  
Forest Canopies ◽  
Closed Canopy ◽  
Filtering Efficiency ◽  
One Year ◽  
The One ◽  
Filtering Effect

Trace metals can enter natural regions with low human disturbance through atmospheric circulation; however, little information is available regarding the filtering efficiency of trace metals by forest canopies. In this study, a representative subalpine spruce plantation was selected to investigate the net throughfall fluxes of eight trace metals (Fe, Mn, Cu, Zn, Al, Pb, Cd and Cr) under a closed canopy and gap-edge canopy from August 2015 to July 2016. Over the one-year observation, the annual fluxes of Al, Zn, Fe, Mn, Cu, Cd, Cr and Pb in the deposited precipitation were 7.29 kg·ha−1, 2.30 kg·ha−1, 7.02 kg·ha−1, 0.16 kg·ha−1, 0.19 kg·ha−1, 0.06 kg·ha−1, 0.56 kg·ha−1 and 0.24 kg·ha−1, respectively. The annual net throughfall fluxes of these trace metals were −1.73 kg·ha−1, −0.90 kg·ha−1, −1.68 kg·ha−1, 0.03 kg·ha−1, −0.03 kg·ha−1, −0.02 kg·ha−1, −0.09 kg·ha−1 and −0.08 kg·ha−1, respectively, under the gap-edge canopy and 1.59 kg·ha−1, −1.13 kg·ha−1, −1.65 kg·ha−1, 0.10 kg·ha−1, −0.04 kg·ha−1, −0.03 kg·ha−1, −0.26 kg·ha−1 and −0.15 kg·ha−1, respectively, under the closed canopy. The closed canopy displayed a greater filtering effect of the trace metals from precipitation than the gap-edge canopy in this subalpine forest. In the rainy season, the net filtering ratio of trace metals ranged from −66.01% to 89.05% for the closed canopy and from −52.32% to 33.09% for the gap-edge canopy. In contrast, the net filtering ratio of all trace metals exceeded 50.00% for the closed canopy in the snowy season. The results suggest that most of the trace metals moving through the forest canopy are filtered by canopy in the subalpine forest.

scholarly journals Behavior, Diet, and Breeding Biology of Double-Toothed Kites at a Guatemalan Lowland Site

The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 113-126 ◽  
Author(s):  
Mark D. Schulze ◽  
Jose LuÍs CÓrdova ◽  
Nathaniel E. Seavy ◽  
David F. Whitacre
Keyword(s):  
Clutch Size ◽  
Rainy Season ◽  
National Park ◽  
Maximum Density ◽  
Lowland Forest ◽  
Tropical Lowland ◽  
Nestling Diet ◽  
Tropical Lowland Forest ◽  
Nestling Period ◽  
Closed Canopy

Abstract We studied Double-toothed Kites (Harpagus bidentatus) in tropical lowland forest at Tikal National Park, Petén, Guatemala, documenting behavior and diet during the incubation and nestling periods. These 200-g kites are Accipiter-like in form and strikingly size-dimorphic for a kite. Modal clutch size was two, producing 0.63 fledglings per nesting attempt and 1.25 per successful nest. Nesting was largely synchronous among pairs, with hatching during the first month of the rainy season and fledging one month later. Incubation lasted 42–45 days and nestlings fledged at 29.5 days on average. A radio-tagged fledgling was fed near the nest for 35 days; 6–8 weeks after fledging it dispersed at least 10 km, presumably reaching independence. Males did not incubate or brood, and rarely fed nestlings directly. Males typically provided most but not all prey (mainly lizards) during incubation and early nestling periods. Insects in the nestling diet increased through the nestling period as females increasingly hunted, often bringing in insects. These kites hunted from perches, below and within the closed canopy of tall, mature forest, taking 60.5% insects, 38.1% lizards, and 1.4% other vertebrates; vertebrates comprised at least 75% of prey biomass. Most prey were taken from vegetation, but prey in flight also were captured. Active, adjacent nests averaged 1.35 km apart, for a maximum density estimate of 0.60 pairs km−2 and a more likely estimate of 0.33–0.50 pairs km−2 in homogeneous, favorable habitat and 0.29–0.44 pairs km−2 for Tikal National Park as a whole.

scholarly journals Forest Gap Size Alters the Functional Diversity of Soil Nematode Communities in Alpine Forest Ecosystems

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 806
Author(s):  
Shen ◽  
Yang ◽  
Zhang ◽  
Xu ◽  
Zhang ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Forest Ecosystems ◽  
Nematode Community ◽  
Soil Nematode ◽  
Gap Size ◽  
Forest Gap ◽  
Forest Gaps ◽  
Alpine Forest ◽  
Soil Nematode Community ◽  
Closed Canopy

Changes in the microenvironment driven by forest gaps have profound effects on soil nutrient cycling and litter decomposition processes in alpine forest ecosystems. However, it is unclear whether a similar forest gap effect occurs in the soil decomposer community. A field experiment was conducted in an alpine forest to investigate the composition and structure of the soil nematode community among four treatments, including under a closed canopy and in small (<10 m in diameter), medium (10‒15 m in diameter), and large (15‒20 m in diameter) gaps. A total of 92,787 individuals and 27 species (genera level) of soil nematode were extracted by elutriation and sugar centrifugation, respectively. Filenchus was the most abundant dominant taxa and represented 24.27%‒37.51% of the soil nematodes in the four treatments. Compared to the closed canopy, the forest gaps did not affect the composition, abundance, or species diversity of the soil nematode community but significantly affected the functional diversity of the soil nematode community. The maturity indices (MI, ∑MI, and MI2‒5) of the soil nematode community in the closed canopy were significantly lower than those in the forest gaps. Moreover, the proportion of plant parasitic index and maturity index (PPI/MI) values of the closed canopy and small gaps were significantly higher than those of the medium and large gaps. Our results suggest that the forest gap size substantially alters the functional diversity of soil nematodes in the debris food web, and changes in soil nematode community structure due to gap formation may have profound effects on soil biogeochemical processes in alpine forests.

Butterfly behavioural responses to natural Bornean tropical rain-forest canopy gaps

2011 ◽  
Vol 28 (1) ◽  
pp. 45-54 ◽  
Author(s):  
James S. Pryke ◽  
Sven M. Vrdoljak ◽  
Paul B. C. Grant ◽  
Michael J. Samways
Keyword(s):  
Rain Forest ◽  
Tropical Rain Forest ◽  
Forest Canopy ◽  
Canopy Gaps ◽  
Tree Canopy ◽  
Canopy Openness ◽  
Butterfly Species ◽  
Behavioural Responses ◽  
Light Heterogeneity ◽  
Closed Canopy

Abstract:Natural tree canopy gaps allow sunlight to penetrate to the forest floor, a major environmental component and resource for many tropical rain-forest species. We compare here how butterflies use sunny areas created by the natural gaps in canopies in comparison with adjacent closed-canopy areas. We chose butterflies as our focal organisms as they are taxonomically tractable and mobile, yet habitat sensitive. Previous studies have shown that butterfly diversity in tropical forests responds to varying degrees of canopy openness. Here we assess butterfly behavioural responses to gaps and equivalent sized closed-canopy patches. Butterfly occupancy time and behaviour were simultaneously observed 61 times in gaps and 61 times in equivalent sized closed-canopy patches across four sites in a tropical rain forest in northern Borneo. Out of the 20 most frequently recorded species, 12 were more frequently recorded or spent more time in gaps, four occurred more frequently in closed-canopy areas, and four showed no significant differences. Overall agonistic, basking, patrolling and resting were more common in gaps compared with the closed canopy. Many butterfly species have complex behavioural requirements for both gaps and closed canopies, with some species using these different areas for different behaviours. Each butterfly species had particular habitat requirements, and needed both canopy gaps and closed canopy areas for ecological and behavioural reasons, emphasizing the need for natural light heterogeneity within these systems.

Seed predation, pathogens and germination in primary vs. secondary cloud forest at Maquipucuna Reserve, Ecuador

2015 ◽  
Vol 31 (4) ◽  
pp. 375-378 ◽  
Author(s):  
Randall W. Myster
Keyword(s):  
Seed Predation ◽  
Human Disturbance ◽  
Secondary Forest ◽  
Cloud Forest ◽  
Primary Forest ◽  
Natural Disturbances ◽  
Seed Loss ◽  
Closed Canopy ◽  
Piper Aduncum ◽  
Maquipucuna Reserve

Abstract:Because the fate of the seed rain has long been shown to be critical to understanding forest recruitment and regeneration, seed predation, seed pathogens and germination among different species was examined in primary (closed-canopy vs. tree-fall gap) and in secondary (banana vs. sugarcane vs. seeded pasture) cloud forest at Maquipucuna Reserve, Ecuador. I found (1) seed predation took more seeds than either seed pathogenic disease or germination for all tree seed species and in both forests, where the level of seed loss to predation was greatest in the closed-canopy primary forest, second largest in the tree-fall gaps and less in recovering banana, sugarcane and pasture; (2) for pathogens these trends were reversed; and (3) most seeds, that were not taken by predators or pathogens, germinated. Cecropia sp. seeds in the tree-fall gaps and Otoba gordoniifolia seeds in both closed-canopy forest and tree-fall gaps were the most significantly different among all treatments in primary forest and Solanum ovalifolia seeds in banana fields and Piper aduncum in all fields were the most significantly different among all treatments in secondary forest. I conclude that forests may recover faster after human disturbance (here agriculture) than after natural disturbances (here tree-fall).

scholarly journals The role of leaf traits and bird-mediated insect predation on patterns of herbivory in a semiarid environment in central Mexico

2017 ◽  
Vol 95 (2) ◽  
pp. 189 ◽  
Author(s):  
Betsabe Ruiz-Guerra ◽  
Erika Nieves-Silva ◽  
Roger Guevara
Keyword(s):  
Structural Characteristics ◽  
Insect Herbivory ◽  
Leaf Traits ◽  
Arid Environments ◽  
Plant Associations ◽  
Main Driver ◽  
Closed Canopy ◽  
One Year ◽  
Insect Predation ◽  
Leaf Strength

<p class="p1"><strong>Background.</strong> In arid environments plants face aridity and herbivory, therefore it has been proposed that both are convergent selective forces. However the drivers of insect herbivory in these ecosystems remain poorly understood.</p><p class="p1"><strong>Question.</strong> Does insect herbivory vary in two plant associations subject to different levels of aridity? To what extent differences in herbivory are determined either by foliar traits, or predation by birds?</p><p class="p1"><strong>Study species</strong>. Citharexylum tetramerum, Viguiera pinnatilobata, and Solanum tridynamum.</p><p class="p1"><strong>Study site</strong>. We compared two-plant associations: the mezquital with a closed canopy and wettest conditions and the tetechera a dry place with an open canopy at the Zapotitlán Valley, México. </p><p class="p1"><strong>Methods</strong>. We evaluated leaf traits (N, C, water content, leaf strength and trichomes), herbivore insects abundance and the effects on herbivory when some predators are excluded.</p><p class="p1"><strong>Results</strong>. Herbivory was higher in the drier site (tetechera) than in the more humid one (mezquital) in one year but not in the second one. In both plant associations herbivory increased when predators of herbivores were excluded. Plants in mezquital had more water and nitrogen content than plants in tetechera. The later had higher carbon concentration and carbon:nitrogen ratio, leaf strength and density of trichomes. Abundance of herbivore insects and insect predation were higher in the most arid site. </p><p class="p1"><strong>Conclusions</strong>. Our results show that insect herbivory increases in the most arid site and that predation by birds plays a role as a driver of herbivory, while resistance to aridity seems to be the main driver of leaf structural characteristics.</p>

Improved Cropping Systems for the Deep Vertisols of the Indian Semi-arid Tropics

1982 ◽  
Vol 18 (3) ◽  
pp. 277-287 ◽  
Author(s):  
M. S. Reddy ◽  
R. W. Willey
Keyword(s):  
Rainy Season ◽  
Cropping Systems ◽  
Maize Crop ◽  
Net Returns ◽  
Wide Range ◽  
Series Of Experiments ◽  
One Year ◽  
Semi Arid ◽  
Crop System

SUMMARYA series of experiments was designed to evaluate a wide range of possible cropping systems for deep Vertisols of the Indian semi-arid tropics. The introduction of a rainy season maize crop, compared with traditional fallowing, had little effect on the yields of post-rainy season crops of sorghum, chickpea and pigeonpea. Introducing a rainy season sorghum crop caused severe yield reductions of post-rainy season crops in one year but only slight reductions in two subsequent years. Intercrop systems of maize/pigeonpea or sorghum/pigeonpea, and a three-crop system of maize/pigeonpea/chickpea, appeared very promising. Gross returns were usually much higher for the improved systems that utilized both the rainy and post-rainy seasons, though differences in net returns were not quite so great because of the extra costs of growing the additional rainy season crops.

scholarly journals Seasonal variation in vertical volatile compounds air concentrations within a remote hemiboreal mixed forest

2012 ◽  
Vol 12 (9) ◽  
pp. 3909-3926 ◽  
Author(s):  
S. M. Noe ◽  
K. Hüve ◽  
Ü. Niinemets ◽  
L. Copolovici
Keyword(s):  
Forest Canopy ◽  
Mixed Forest ◽  
Oxidation Reactions ◽  
Aerosol Formation ◽  
Forest Canopies ◽  
Air Chemistry ◽  
Anthropogenic Contributions ◽  
One Year ◽  
Winter Time ◽  
The Vertical Distribution

Abstract. The vertical distribution of ambient biogenic volatile organic compounds (BVOC) concentrations within a hemiboreal forest canopy was investigated over a period of one year. Variability in temporal and spatial isoprene concentrations, ranging from 0.1 to 7.5 μg m−3, can be mainly explained by biogenic emissions from deciduous trees. Monoterpene concentrations exceeded isoprene largely and ranged from 0.01 to 140 μg m−3 and during winter time anthropogenic contributions are likely. Variation in monoterpene concentrations were found to be largest right above the ground and the vertical profiles suggest a weak mixing leading to terpene accumulation in the lower canopy. Exceptionally high values were recorded during a heat wave in July 2010 with very high midday temperatures above 30 °C for several weeks. During summer months, monoterpene exceeded isoprene concentrations 6-fold and during winter 12-fold. During summer months, dominance of α-pinene in the lower and of limonene in the upper part of the canopy was observed, both accounting for up to 70% of the total monoterpene concentration. During wintertime, Δ3-carene was the dominant species, accounting for 60% of total monoterpene concentration in January. Possible biogenic monoterpene sources beside the foliage are the leaf litter, the soil and also resins exuding from stems. In comparison, the hemiboreal mixed forest canopy showed similar isoprene but higher monoterpene concentrations than the boreal forest and lower isoprene but substantially higher monoterpene concentrations than the temperate mixed forest canopies. These results have major implications for simulating air chemistry and secondary organic aerosol formation within and above hemiboreal forest canopies. Possible effects of in-cartridge oxidation reactions are discussed as our measurement technique did not include oxidant scavenging. A comparison between measurements with and without scavenging oxidants is presented.

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