Floor Litter Research Articles

Comparative performances of hilly chicken and naked neck hilly chicken at Naikhongchari hilly areas of Bangladesh

A total of 115 hilly chickens (92 female and 23 males) and 35 naked neck hilly Chickens (28 females and 7 males) were reared in open sided poultry house for 10 months period to compare their productive and reproductive performances. The mean body weights of adult female and male hilly birds and naked neck hilly birds were 2244, 2005 and 2664, 2576 g respectively. The age at first egg of both type of birds were 147 and 159 days respectively and hen-day egg production were 27±1.4 and 35±3.3 respectively. The average egg weight was 41±4 and 38±3.6 g respectively. Both type of bird per day average feed consumption were 97.61±11 and 102±22 g and mortality were 15.56±3.7 and 11.42±2.7 percent respectively. The average hatchability percentage performed by 14 broody hens reared on litter floor was 67.5±10 and 57±22 percent respectively. The average hatching egg weight and chick weight were 47.28±3, 41.48±1 and 31.4±3, 29.6±4 g respectively. The body weight of growing hilly bird and Naked Neck hilly bird after eleven weeks of age were 727.3±17.4 and 645±97.6g, respectively and Feed conversion ratios (FCR) were 3.39 and 3.34 respectively. It was concluded that Hilly chicken improved by body weight than previous year and both feathered and Naked Neck Hilly chicken given an indication of meat type native chicken and required to reproduce to have large stock for undertaking conservation and further improvement programme.Asian J. Med. Biol. Res. June 2016, 2(2): 348-351

Environmental assessment of three egg production systems – Part III: Airborne bacteria concentrations and emissions

Airborne microorganism level is an important indoor air quality indicator, yet it has not been well documented for laying-hen houses in the United States. As a part of the Coalition for Sustainable Egg Supply (CSES) environmental monitoring project, this study comparatively monitored the concentrations and emissions of airborne total and Gram-negative (Gram−) bacteria in three types of commercial laying-hen houses, i.e., conventional cage (CC), aviary (AV), and enriched colony (EC) houses, over a period of eight months covering the mid and late stages of the flock cycle. It also delineated the relationship between airborne total bacteria and particulate matter smaller than 10 μm in aerodynamic diameter (PM10). The results showed airborne total bacteria concentrations (log CFU/m3) of 4.7 ± 0.3 in CC, 6.0 ± 0.8 in AV, and 4.8 ± 0.3 in EC, all being higher than the level recommended for human environment (3.0 log CFU/m3). The much higher concentrations in AV arose from the presence of floor litter and hen activities on it, as evidenced by the higher concentrations in the afternoon (with litter access) than in the morning (without litter access). The overall means and standard deviation of airborne total bacteria emission rates, in log CFU/[h-hen] (or log CFU/[h-AU], AU = animal unit or 500 kg live weight) were 4.8 ± 0.4 (or 7.3 ± 0.4) for CC, 6.1 ± 0.7 (or 8.6 ± 0.7) for AV, and 4.8 ± 0.5 (or 7.3 ± 0.5) for EC. Both concentration and emission rate of airborne total bacteria were positively related to PM10. Gram− bacteria were present at low concentrations in all houses; and only 2 samples (6%) in CC, 7 (22%) samples in AV, and 2 (6%) samples in EC out of 32 air samples collected in each house were found positive with Gram− bacteria. The concentration of airborne Gram− bacteria was estimated to be <2% of the total bacteria. Total bacteria counts in manure on belt (in all houses) and floor litter (only in AV) were similar; however, the manure had much more Gram− bacteria than the litter. The results point out the need to mitigate airborne total bacteria in laying-hen houses, especially in AV houses.

Ecosystem carbon stock across a chronosequence of spruce plantations established on cutovers of a high-elevation region

This study quantified the above- and belowground carbon (C) stocks across a chronosequence of spruce (Picea asperata) plantations established on cutovers and explored the turning point after which the increase in biomass C slowed or biomass C decreased for guiding forest management. We assessed above- and belowground plant biomass stocks at 11 sites in three regions, representing 12- to 46-year-old spruce plantations established on clear-cut areas in the eastern Tibetan Plateau, China. Biomass and C stocks of trees, understory vegetation, and forest floor litter were determined from plot-level inventories and destructive sampling. Fine root (<2 mm) biomass and mineral soil organic C (SOC) stock were estimated from soil cores. Tree biomass was quantified using allometric equations based on diameter at breast height (DBH) and height (H). Plant biomass C stocks in spruce plantations rapidly increased from 12 to 20 years at a rate of 7.8 Mg C ha−1 year−1, but decreased from 25 to 46 years at a rate of 0.79 Mg C ha−1 year−1. SOC stocks in spruce plantations gradually decreased from 12 to 46 years at a rate of 4.4 Mg C ha−1 year−1. Total C stock in the ecosystem remained unchanged for the first 20 years after the planting of spruce on cutovers, because the buildup of C stock in spruce biomass during the first 20 years was offset by the decrease in SOC. From 21 to 46 years after the reforestation, ecosystem C stock even decreased at a rate of 5.2 Mg C ha−1 year−1. The contribution of the understory vegetation, forest floor litter, and fine root to ecosystem C stock was low (<5.0 %) in the spruce plantations. Ecosystem C stock in the spruce forest established on the cutover in the eastern Tibetan Plateau was related to stand age. During the first 20 years, this ecosystem was C neutral. However, aged (20–46 years) spruce plantation ecosystem can be a C source if no management was implemented to revitalize tree growth, promote understory vegetation, and enhance SOC accumulation.

Altitudinal patterns and controls of plant and soil nutrient concentrations and stoichiometry in subtropical China.

Altitude is a determining factor of ecosystem properties and processes in mountains. This study investigated the changes in the concentrations of carbon (C), nitrogen (N), and phosphorus (P) and their ratios in four key ecosystem components (forest floor litter, fine roots, soil, and soil microorganisms) along an altitudinal gradient (from 50 m to 950 m a.s.l.) in subtropical China. The results showed that soil organic C and microbial biomass C concentrations increased linearly with increasing altitude. Similar trends were observed for concentrations of total soil N and microbial biomass N. In contrast, the N concentration of litter and fine roots decreased linearly with altitude. With increasing altitude, litter, fine roots, and soil C:N ratios increased linearly, while the C:N ratio of soil microbial biomass did not change significantly. Phosphorus concentration and C:P and N:P ratios of all ecosystem components generally had nonlinear relationships with altitude. Our results indicate that the altitudinal pattern of plant and soil nutrient status differs among ecosystem components and that the relative importance of P vs. N limitation for ecosystem functions and processes shifts along altitudinal gradients.

Wildlife habitat management: concepts and applications in forestry

Wildlife habitat management: concepts and applications in forestry

Water activity of poultry litter: Relationship to moisture content during a grow-out

Poultry grown on litter floors are in contact with their own waste products. The waste material needs to be carefully managed to reduce food safety risks and to provide conditions that are comfortable and safe for the birds. Water activity (Aw) is an important thermodynamic property that has been shown to be more closely related to microbial, chemical and physical properties of natural products than moisture content. In poultry litter, Aw is relevant for understanding microbial activity; litter handling and rheological properties; and relationships between in-shed relative humidity and litter moisture content. We measured the Aw of poultry litter collected throughout a meat chicken grow-out (from fresh pine shavings bedding material to day 52) and over a range of litter moisture content (10–60%). The Aw increased non-linearly from 0.71 to 1.0, and reached a value of 0.95 when litter moisture content was only 22–33%. Accumulation of manure during the grow-out reduced Aw for the same moisture content. These results are relevant for making decisions regarding litter re-use in multiple grow-outs as well as setting targets for litter moisture content to minimise odour, microbial risks and to ensure necessary litter physical conditions are maintained during a grow-out. Methods to predict Aw in poultry litter from moisture content are proposed.

Soil microbial responses to forest floor litter manipulation and nitrogen addition in a mixed-wood forest of northern China.

Changes in litterfall dynamics and soil properties due to anthropogenic or natural perturbations have important implications to soil carbon (C) and nutrient cycling via microbial pathway. Here we determine soil microbial responses to contrasting types of litter inputs (leaf vs. fine woody litter) and nitrogen (N) deposition by conducting a multi-year litter manipulation and N addition experiment in a mixed-wood forest. We found significantly higher soil organic C, total N, microbial biomass C (MBC) and N (MBN), microbial activity (MR), and activities of four soil extracellular enzymes, including β-glucosidase (BG), N-acetyl-β-glucosaminidase (NAG), phenol oxidase (PO), and peroxidase (PER), as well as greater total bacteria biomass and relative abundance of gram-negative bacteria (G-) community, in top soils of plots with presence of leaf litter than of those without litter or with presence of only fine woody litter. No apparent additive or interactive effects of N addition were observed in this study. The occurrence of more labile leaf litter stimulated G-, which may facilitate microbial community growth and soil C stabilization as inferred by findings in literature. A continued treatment with contrasting types of litter inputs is likely to result in divergence in soil microbial community structure and function.

Feather eating and its associations with plumage damage and feathers on the floor in commercial farms of laying hens

Feather eating has been associated with feather pecking, which continues to pose economic and welfare problems in egg production. Knowledge on feather eating is limited and studies of feather eating in commercial flocks of laying hens have not been performed previously. Therefore, the main objective was to investigate feather eating and its association with plumage damage and floor feather characteristics in commercial flocks of layers in barn and organic production systems. The study was performed in 13 flocks of barn layers and 17 flocks of organic layers. Each flock was visited at around 32 and 62 weeks of age. During both visits, the plumage condition was assessed and the density of floor feathers recorded. In week 62, droppings and floor feathers were collected. Droppings were examined for presence of feather content, whereas length, downiness and pecking damage were recorded for each floor feather. In week 62, a higher prevalence of hens with poor plumage condition was found in barn (22.2%) compared with organic production systems (7.4%; P<0.001), but the prevalence of droppings with feather content did not differ between the two production systems (8.5% in barn v. 4.3% in organic; P=0.99). Our hypothesis about a positive correlation between feather eating and plumage damage was not supported as no correlation was found between the prevalence of poor plumage condition and the prevalence of droppings with feather content. However, the prevalence of pecking damaged floor feathers was positively correlated both with prevalence of droppings with feather content (P<0.05) and poor plumage condition (P<0.01), indicating a possible association between feather eating and feather pecking. In conclusion, it was confirmed that feather eating occurs on-farm, but feather eating was only found to be positively correlated to the number of floor feathers with pecking damage and not as expected to the prevalence of plumage damage. More research is needed into the sources from where feathers are selected for ingestion, that is, whether they are picked from the floor litter, plucked directly from other hens or dislodged during preening of own feathers.

Impact of shifting cultivation on litter accumulation and properties of Jhum soils of north east India

This study assessed whether the slash-burn practice (jhum) induced disturbance on the above-ground biological inputs (plant biomass and forest floor litters, FFLs) had any influence on the soil processes in terms of soil enzyme activities. The jhum cycles of 5, 10 and 15 years from Mizoram and 5, 10 and 20 years from Nagaland were considered. Litter (adjacent fallow phase/secondary forest) and soil samples (burnt and unburnt cropping phases) were collected from three slopes (summit, shoulder and backslope) from each site and were analyzed for soil physicochemical and biochemical properties. Accumulation of FFLs increased significantly with the increasing length of fallow phase and accumulation dynamics showed an increasing trend in the order January > April > August > November. Values of bulk density (BD), pH, electrical conductivity (EC), avail-P and avail-K in soils under burnt sites were found higher relative to their values in unburnt sites and the reverse trend was true in case of soil organic carbon (SOC) and avail-N. Except BD, values of these soil properties were significantly higher in the longer fallow phase compared to that in shorter fallow phase (P<0.05, Kruskal-Wallis test). The activity of soil enzymes viz. amylase (AMY), β-glucosidase (GSA), dehydrogenase (DHA), aryl-sulphatase (ASA), acid-phosphatase (PHA) and protease (PRO) were differed significantly between burnt and unburnt or among fallow phases (P<0.05, Kruskal-Wallis test). The activities of DHA, GSA, PRO and PHA in burnt soils were decreased, whereas ASA activity increased relative to unburnt soils. Activities of AMY, GSA, DHA, ASA, PHA and PRO were significantly higher in longer fallow phase than that in shorter fallow phase. In exception under burnt condition, AMY and GSA activities were significantly lower in longer fallow phase than that in short fallow phase. In conclusion, burning of biomass releases a higher quantum of plant available nutrients in jhum soils momentarily, which can support better crop growth under longer fallow lengths. However, burning practice negatively impacted the biochemical processes of jhum soils indicating a gradual decline in the inherent nutrient cycling potentials of soils under jhum cycles.

Laying hen movement in a commercial aviary: Enclosure to floor and back again

Many producers in the laying hen industry, including in North America, are phasing out conventional cages in response to consumer demands and sometimes subsequent legislation. Alternative housing systems such as aviaries are being implemented in an attempt to improve hen welfare. Aviaries provide additional space and resources to groups of hens, including a litter area on the floor. However, little is known about hen movement between tiered enclosures and floor litter areas in aviary systems. Diurnal rhythms and social attraction may result in peak times of movement that could lead to overcrowding of areas, or alternatively hen preferences may lead to some areas not being fully utilized. We monitored hen movement between tiered enclosures and litter areas, including movement on and off the outer perch, across the day at peak, mid and end of lay in a commercial aviary. Hens moved onto and off of the open litter area across the day, transitioning between tiered enclosures, outer perches, open litter areas, and litter areas under tiered enclosures. At certain times of day, there were periods of greater hen movement down to the open litter area and between litter areas. For example, more hens were typically observed exiting enclosures, jumping from perches to open litter, and traveling between open litter and litter under tiered enclosures in the morning (all P ≤ 0.001). In all but one instance, more hens were observed on open litter areas in the afternoon than at other times of day (all P ≤ 0.029). However, hen re-entry to tiered enclosures showed less circadian patterning. Hen movement was observed between areas of interest at all sampled time periods, indicating hens use all areas of the system. Further research should examine whether all individual hens do move between areas equally, including within levels of the tiered enclosure, or if crowding occurs on the outer perches or in the litter during times of peak movement.

Ảnh hưởng các yếu tố môi trường chuồng nuôi lên sinh trưởng của gà thịt

Four broiler houses located on the same farm belonged to Emivest Vietnam Co., Ltd in Binh Phuoc province were selected to evaluate the effect of indoor environmental factors including temperature (oC), relative humidity (%), air velocity (m/s), concentration of O2 (%), NH3, H2S, CO and CH4 (ppm) and the presence of Escherichia coli and Eimeria spp. in houses on growth rate, feed intake and feed conversion ratio of one to 42 day old chicks. All birds were kept in tunnel-ventilated houses and raised on deep litter floor, which was divided into 4 equal positions of 360 m2. The measurement showed that there was no harmful gas detected, O2 concentration was maintained at normal level (20.9 vol%). Number of fecal E.coli was 14*106 CFU/g with no presence of Eimeria spp. The final weight of birds reared near vent fans was higher to that of birds in the exhaust fans (3,026 g vs 2871 g, p

Budget and distribution of organic carbon in Quercus serrata Thunb. ex Murray forest in Mt. Worak

The carbon cycle came into the spotlight due to the climate change and forests are well-known for their capacity to store carbon amongst other terrestrial ecosystems. The annual organic carbon of litter production, forest floor litter layer, soil, aboveground and belowground part of plant, standing biomass, net primary production, uptake of organic carbon, soil respiration, etc. were measured in Mt. Worak in order to understand the production and carbon budget of Quercus serrata forest that are widely spread in the central and southern part of the Korean Peninsula. The total amount of organic carbon of Q. serrata forest during the study period (2010-2013) was 130.745 ton C ha^-1. The aboveground part of plant, belowground part of plant, forest floor litter layer, and organic carbon in soil was 50.041, 12.510, 4.075, and 64.119 ton C ha^-1, respectively. The total average of carbon fixation in plants from photosynthesis was 4.935 ton C ha^-1 yr^-1 and organic carbon released from soil respiration to microbial respiration was 3.972 ton C ha^-1 yr^-1. As a result, the net ecosystem production of Q. serrata forest estimated from carbon fixation and soil respiration was 0.963 ton C ha^-1 yr^-1. Therefore, it seems that Q. serrata forest can act as a sink that absorbs carbon from the atmosphere. The carbon uptake of Q. serrata forest was highest in stem of the plant and the research site had young forest which had many trees with small diameter at breast height (DBH). Consequentially, it seems that active matter production and vigorous carbon dioxide assimilation occurred in Q. serrata forest and these results have proven to be effective for Q. serrata forest to play a role as carbon storage and NEP.

Soil CO2 efflux among four coniferous forest types of Kashmir Himalaya, India.

Soil CO2 efflux was measured in four different coniferous forest types (Cedrus deodara (CD), Pinus wallichiana (PW), mixed coniferous (MC), and Abies pindrow (AP)) for a period of 2 years (April 2012 to December 2013). The monthly soil CO2 efflux ranged from 0.8 to 4.1 μmoles CO2 m(-2) s(-1) in 2012 and 1.01 to 5.48 μmoles CO2 m(-2) s(-1) in 2013. The soil CO2 efflux rate was highest in PW forest type in both the years, while it was lowest in MC and CD forest types during 2012 and 2013, respectively. Soil temperature (TS) at a depth of 10 cm ranged from 3.8 to 19.4 °C in 2012 and 3.5 to 19.1 °C in 2013 in all the four forest types. Soil moisture (MS) ranged from 19.8 to 58.6% in 2012 and 18.5 to 58.6% in 2013. Soil CO2 efflux rate was found to be significantly higher in summer than the other seasons and least during winter. Soil CO2 efflux showed a significant positive relationship with TS (R2=0.52 to 0.74), SOC% (R2=0.67), pH (R2=0.68), and shrub biomass (R2=0.51), whereas, only a weak positive relationship was found with soil moisture (R2=0.16 to 0.41), tree density (R2=0.25), tree basal area (R2=0.01), tree biomass (R2=0.07), herb biomass (R2=0.01), and forest floor litter (R2=0.02). Thus, the study indicates that soil CO2 efflux in high mountainous areas is greatly influenced by seasons, soil temperature, and other environmental factors.

Foliar nutrient resorption constrains soil nutrient transformations under two native oak species in a temperate deciduous forest in Mexico

Foliar nutrient resorption (FNR) is a key pro- cess in the dynamics of nutrients in a forest ecosystem. Along with other factors, FNR regulates the chemical composition of the forest floor and, consequently, the rates of organic matter decomposition and soil nutrient avail- ability. The main objective of the present study was to examine the effect of FNR of two deciduous oak species (Quercus castanea and Q. deserticola) in the litter and soil nutrient dynamics, in addition to analyze whether the interaction between two species was positive (synergistic) or negative (antagonistic) through the mixed litter from two species. For this purpose, the nutrient concentration of green leaves, litterfall, litter and soil was measured, as well as soil microbial activity. These measurements were taken in isolated stands with the presence of one of the oak species and stands with the two oak species mixed. Quer- cus deserticola, with lower FNR, produced litter with a higher N concentration, which apparently enhancing microbial activity in the forest floor litter and increased nutrient transformations and soil fertility. In contrast, Q. castanea has a higher FNR and produced litter with a lower nutrient concentration. The microbial soil community associated with Q. castanea must therefore invest more energy in metabolic processes at the expense of biomass growth. However, forest floor nutrient transformations were more intense and soil fertility increased in areas where both species intermix; in this case, the latter species received the rich-nutrient litterfall of Q. deserticola. These results suggest a strong footprint of species traits on microbial activities and soil nutrient transformations.

Forest floor community metatranscriptomes identify fungal and bacterial responses to N deposition in two maple forests.

Anthropogenic N deposition alters patterns of C and N cycling in temperate forests, where forest floor litter decomposition is a key process mediated by a diverse community of bacteria and fungi. To track forest floor decomposer activity we generated metatranscriptomes that simultaneously surveyed the actively expressed bacterial and eukaryote genes in the forest floor, to compare the impact of N deposition on the decomposers in two natural maple forests in Michigan, USA, where replicate field plots had been amended with N for 16 years. Site and N amendment responses were compared using about 74,000 carbohydrate active enzyme transcript sequences (CAZymes) in each metatranscriptome. Parallel ribosomal RNA (rRNA) surveys of bacterial and fungal biomass and taxonomic composition showed no significant differences in either biomass or OTU richness between the two sites or in response to N. Site and N amendment were not significant variables defining bacterial taxonomic composition, but they were significant for fungal community composition, explaining 17 and 14% of the variability, respectively. The relative abundance of expressed bacterial and fungal CAZymes changed significantly with N amendment in one of the forests, and N-response trends were also identified in the second forest. Although the two ambient forests were similar in community biomass, taxonomic structure and active CAZyme profile, the shifts in active CAZyme profiles in response to N-amendment differed between the sites. One site responded with an over-expression of bacterial CAZymes, and the other site responded with an over-expression of both fungal and different bacterial CAZymes. Both sites showed reduced representation of fungal lignocellulose degrading enzymes in N-amendment plots. The metatranscriptome approach provided a holistic assessment of eukaryote and bacterial gene expression and is applicable to other systems where eukaryotes and bacteria interact.

Plant and soil δ13C and δ15N are linked to community biomass, litter production, and litter turnover rate in mature subtropical forests

The natural abundance of 13C and 15N can integrate information on the dynamics of C and N, respectively. This study tested whether and how δ13C and δ15N of the plant and soil samples (including leaf, forest floor litters, fine roots, and 0–15 cm mineral soil) can detect local variations in community biomass, litter production, and litter turnover rate were explored in eight mature subtropical forests in southern China. Community biomass, litter production, and litter turnover rate were significantly positively correlated with each other and revealed similar correlations with other plant and soil parameters. Leaf δ13C was significantly negatively correlated with litter production, suggesting the stomatal regulation of leaf gas exchange. Similar correlations were also observed for δ13C of the mineral soil and other plant materials. Leaf and forest floor litters δ15N were positively correlated with community biomass, litter production, and litter turnover rate. Such correlations were significantly positively mediated by soil availability of P rather than N, as demonstrated by the multiple regression analysis. In contrast, fine roots δ15N was not related significantly to community biomass, litter production, or litter turnover rate. Significant differences in δ13C and δ15N among forests were related to the species composition, topography conditions, and land use history. Our results suggest that δ13C and δ15N of most plant and soil samples can indicate local variations in community biomass, litter production, and litter turnover rate in mature subtropical forests. Better understanding of these linkages could significantly improve our knowledge of C and N dynamics in forest ecosystems.

Where Occupation and Environment Overlap: US Forest Service Worker Exposure to Libby Amphibole Fibers

The National Institute for Occupational Safety and Health (NIOSH) conducted an evaluation of exposures to asbestiform amphibole, known as Libby Amphibole (LA), to personnel from the US Department of Agriculture-Forest Service (USFS) working in the Kootenai National Forest near a former vermiculite mine close to Libby, Montana. LA is associated with vermiculite that was obtained from this mine; mining and processing over many years have resulted in the spread of LA into the surrounding Kootenai Forest where it has been found in tree bark, soil, and forest floor litter. As a result of this and other contamination, Libby and surrounding areas have been designated a “Superfund” site by the US Environmental Protection Agency (EPA). This article describes the application of EPA methods for assessing cancer risks to NIOSH sampling results. Phase-contrast microscopy for airborne asbestos fiber evaluation was found to be less useful than transmission electron microscopy in the presence of interfering organic (plant) fibers. NIOSH Method 7402 was extended by examination of larger areas of the filter, but fiber counts remained low. There are differences between counting rules in NIOSH 7402 and the ISO method used by EPA but these are minor in the context of the uncertainty in concentration estimates from the low counts. Estimates for cancer risk are generally compatible with those previously estimated by the EPA. However, there are limitations to extrapolating these findings of low risk throughout the entire area and to tasks that were not evaluated.

Environmental assessment of three egg production systems–Part I: Monitoring system and indoor air quality

To comprehensively assess conventional vs. some alternative laying-hen housing systems under U.S. production conditions, a multi-institute and multi-disciplinary project, known as the Coalition for Sustainable Egg Supply (CSES) study, was carried out at a commercial egg production farm in the Midwestern United States over two single-cycle production flocks. The housing systems studied include a conventional cage house (200,000 hen capacity), an aviary house (50,000 hen capacity), and an enriched colony house (50,000 hen capacity). As an integral part of the CSES project, continual environmental monitoring over a 27-month period described in this paper quantifies indoor gaseous and particulate matter concentrations, thermal environment, and building ventilation rate of each house. Results showed that similar indoor thermal environments in all three houses were maintained through ventilation management and environmental control. Gaseous and particulate matter concentrations of the enriched colony house were comparable with those of the conventional cage house. In comparison, the aviary house had poorer indoor air quality, especially in wintertime, resulting from the presence of floor litter (higher ammonia levels) and hens’ activities (higher particulate matter levels) in it. Specifically, daily mean indoor ammonia concentrations had the 95% confidence interval values of 3.8 to 4.2 (overall mean of 4.0) ppm for the conventional cage house; 6.2 to 7.2 (overall mean of 6.7) ppm for the aviary house; and 2.7 to 3.0 (overall mean of 2.8) ppm for the enriched colony house. The 95% confidence interval (overall mean) values of daily mean indoor carbon dioxide concentrations were 1997 to 2170 (2083) ppm for the conventional cage house, 2367 to 2582 (2475) ppm for the aviary house, and 2124 to 2309 (2216) ppm for the enriched colony house. Daily mean indoor methane concentrations were similar for all three houses, with 95% confidence interval values of 11.1 to 11.9 (overall mean of 11.5) ppm. The 95% confidence interval values (overall mean) of daily mean PM10 and PM2.5 concentrations, in mg/m3, were, respectively, 0.57 to 0.61 (0.59) and 0.033 to 0.037 (0.035) for the conventional cage house, 3.61 to 4.29 (3.95) and 0.374 to 0.446 (0.410) for the aviary house, and 0.42 to 0.46 (0.44) and 0.054 to 0.059 (0.056) for the enriched colony house. Investigation of mitigation practices to improve indoor air quality of the litter-floor aviary housing system is warranted.

Variation of biomass and carbon pools with forest type in temperate forests of Kashmir Himalaya, India.

An accurate characterization of tree, understory, deadwood, floor litter, and soil organic carbon (SOC) pools in temperate forest ecosystems is important to estimate their contribution to global carbon (C) stocks. However, this information on temperate forests of the Himalayas is lacking and fragmented. In this study, we measured C stocks of tree (aboveground and belowground biomass), understory (shrubs and herbaceous), deadwood (standing and fallen trees and stumps), floor litter, and soil from 111 plots of 50 m × 50 m each, in seven forest types: Populus deltoides (PD), Juglans regia (JR), Cedrus deodara (CD), Pinus wallichiana (PW), mixed coniferous (MC), Abies pindrow (AP), and Betula utilis (BU) in temperate forests of Kashmir Himalaya, India. The main objective of the present study is to quantify the ecosystem C pool in these seven forest types. The results showed that the tree biomass ranged from 100.8 Mg ha(-1) in BU forest to 294.8 Mg ha(-1) for the AP forest. The understory biomass ranged from 0.16 Mg ha(-1) in PD forest to 2.36 Mg ha(-1) in PW forest. Deadwood biomass ranged from 1.5 Mg ha(-1) in PD forest to 14.9 Mg ha(-1) for the AP forest, whereas forest floor litter ranged from 2.5 Mg ha(-1) in BU and JR forests to 3.1 Mg ha(-1) in MC forest. The total ecosystem carbon stocks varied from 112.5 to 205.7 Mg C ha(-1) across all the forest types. The C stocks of tree, understory, deadwood, litter, and soil ranged from 45.4 to 135.6, 0.08 to 1.18, 0.7 to 6.8, 1.1 to 1.4, and 39.1-91.4 Mg ha(-1), respectively, which accounted for 61.3, 0.2, 1.4, 0.8, and 36.3 % of the total carbon stock. BU forest accounted 65 % from soil C and 35 % from biomass, whereas PD forest contributed only 26 % from soil C and 74 % from biomass. Of the total C stock in the 0-30-cm soil, about 55 % was stored in the upper 0-10 cm. Soil C stocks in BU forest were significantly higher than those in other forests. The variability of C pools of different ecosystem components is influenced by vegetation type, stand structure, management history, and altitude. Our results reveal that a higher percentage (63 %) of C is stored in biomass and less in soil in these temperate forests except at the higher elevation broad-leaved BU forest. Results from this study will enhance our ability to evaluate the role of these forests in regional and global C cycles and have great implications for planning strategies for conservation. The study provides important data for developing and validating C cycling models for temperate forests.

Seral changes in ant (Hymenoptera: Formicidae) assemblages in the sub‐boreal forests of British Columbia

Abstract Despite their ubiquity, ant assemblages in the sub‐boreal forests of British Columbia, Canada, are largely unknown. Ant assemblages and area densities of species colonies were characterised in lodgepole pine‐leading forests through strip‐plot hand sampling of coarse woody debris (CWD), with species richness supplementation through pitfall trapping and mini‐Winkler sampling of forest floor litter, over five seral ages. Seventeen species of ants were identified across all seral ages. Ant assemblage dissimilarity (non‐metric multidimensional scaling) determined from CWD (i.e. ordination separation between sites) decreased through early seral ages then began to increase in later seral ages. Despite a species richness curve superficially consistent with competitive exclusion developing in later seral ages, the overall decline in all species abundances with advancing seral age, the low colony densities, and the persistence of only an ecologically subordinate species in the oldest seral age, argued against competitive exclusion and for a thermally based hypothesis of evolved species tolerance. Successional facilitation and examples of the role of individual life history characteristics were also noted with seral progression.