Variation in mass and nutrient concentration of leaf litter across years and sites in a northern hardwood forest

2012 ◽  
Vol 42 (8) ◽  
pp. 1597-1610 ◽  
Author(s):  
Ruth D. Yanai ◽  
Mary A. Arthur ◽  
Marty Acker ◽  
Carrie R. Levine ◽  
Byung Bae Park
Keyword(s):  
Leaf Litter ◽  
Nutrient Concentration ◽  
Optimal Allocation ◽  
Research Effort ◽  
Phosphorus Concentration ◽  
Nutrient Analysis ◽  
Northern Hardwood ◽  
Leaf Litterfall ◽  
Species Specific ◽  
Over Time

Leaf litterfall represents an important nutrient flux in forests, but separating leaves by species and collecting fresh litter annually for nutrient analysis is time-consuming and expensive. To quantify the sources of variation in litterfall nutrient estimates and guide optimal allocation of research effort, we analyzed nutrient concentration (5 years) and mass (6 years) of leaf litter for nine tree species in 13 northern hardwood sites. Coefficients of variation (CVs) in nutrient concentration were higher across sites than over time within sites for most elements; phosphorus was especially variable across sites (56% CV). Thus, to estimate litterfall nutrient fluxes accurately in forests of this type, nutrient analyses should be site-specific as well as species-specific but may not need to be repeated annually (CVs over time averaged 17% for calcium, 21% for magnesium, 28% for potassium, and 32% for phosphorus concentration). Total leaf litterfall mass varied considerably from year to year, ranging from 234 to 370 g·m–2 averaged over 13 sites. We recommend that litter collectors be elevated above the ground to avoid oversampling during extreme wind events. Use of species-specific allometric equations, or even basal area, to estimate the species composition of total litter mass may obviate the need to sort litter by species.

scholarly journals Reactivation of nutrient cycling in an urban tropical dry forest after abandonment of agricultural activities

2021 ◽  
Vol 27 (3) ◽  
pp. 355-365
Author(s):  
Juan D. León-Peláez ◽  
◽  
William Caicedo-Ruiz ◽  
Jeiner Castellanos-Barliza ◽  
◽  
...  
Keyword(s):  
Organic Matter ◽  
Leaf Litter ◽  
Residence Time ◽  
Mean Residence Time ◽  
Dry Forest ◽  
Agricultural Activities ◽  
Forest Fragment ◽  
Leaf Litterfall ◽  
Passive Restoration ◽  
Standing Litter

Introduction: Standing leaf litter represent an essential source of organic matter and nutrients to dynamize biogeochemical processes at the ecosystem level. Objectives: To characterize the accumulation and decomposition of organic materials and flow of nutrients from standing litter in an urban dry tropical forest in a successional stage, after 10 years of abandonment of agricultural activities, and to determine the potential use of three species in future active restoration activities. Materials and methods: Standing litter samples were collected from a forest fragment in Santa Marta, Colombia, separating leaves, reproductive material, woody material and other residues. Additionally, leaves of three species of interest for ecological restoration (Albizia niopoides Spruce ex Benth., Cordia alba [Jacq.] Roem. & Schult. and Machaerium milleflorum Dugand G. A.) were separated and Ca, Mg, K, N and P concentrations were determined. Results and discussion: Total standing litter was 8.3 Mg∙ha-1 with a mean residence time of two years. The leaves represented 20% of the standing litter, with a mean residence time of 1.4 years. Based on the decomposition constant (kj = 0.73) and the rate of leaf litterfall, organic matter returns accounted for 3.4 Mg∙ha-1∙year-1. Leaf decomposition rate decreased in the following order C. alba > M. milleflorum > A. niopoides. P represented the greatest limitation with low release rates (0.1 to 1.2 kg∙ha-1∙year-1). Conclusions: The passive restoration strategy allowed reactivation of biogeochemical cycle via fine leaf litter. Cordia alba showed potential for inclusion in restoration activities, with lower values for leaf N/P ratio, and higher rates for leaf litterfall, litter decomposition and nutrient release.

Foliar sulfur and nitrogen along an 800-km pollution gradient

1992 ◽  
Vol 22 (11) ◽  
pp. 1761-1769 ◽  
Author(s):  
Kurt S. Pregitzer ◽  
Andrew J. Burton ◽  
Glenn D. Mroz ◽  
Hal O. Liechty ◽  
Neil W. MacDonald
Keyword(s):  
Leaf Litter ◽  
Acidic Deposition ◽  
N Deposition ◽  
Hardwood Forests ◽  
Litter Fall ◽  
Pollution Gradient ◽  
Northern Hardwood Forests ◽  
Northern Hardwood ◽  
Molar Ratios ◽  
Foliar S

Emissions of sulfur (S) and nitrogen (N) oxides in the midwestern and northeastern United States result in pronounced regional gradients of acidic deposition. The objective of this study was to determine the extent to which atmospheric deposition alters the uptake and cycling of S and N in five analogous northern hardwood forests located along one of the most pronounced regional gradients of SO42−-S and NO3−-N deposition in the United States. We tested the hypothesis that acidic deposition would alter foliar S and N ratios and nutrient cycling in aboveground litter fall. Sulfate in both wet deposition and throughfall increased by a factor of two across the 800-km deposition gradient. The July concentration of S in sugar maple (Acersaccharum Marsh.) leaves increased from about 1600 μg•g−1 at the northern research sites to 1800–1900 μg•g−1 at the southern sites. Differences in leaf litter S concentration were even more pronounced (872–1356 μg•g−1), and a clear geographic trend was always apparent in litter S concentration. The 3-year average S content of leaf litter was 63% greater at the southern end of the pollution gradient. Nitrate and total N deposition were also significantly greater at the southern end of the gradient. The concentration of N in both summer foliage and leaf litter was not correlated with N deposition, but the content of N in leaf litter was significantly correlated with N deposition. The molar ratios of S:N in mid-July foliage and leaf litter increased as atmospheric deposition of SO42−-S increased. Ratios of S:N were always much greater in leaf litter than in mid-July foliage. The molar ratios of S:N retranslocated from the canopies of these northern hardwood forests were less than those in mid-July foliage or litter fall and showed no geographic trend related to deposition, suggesting that S and N are retranslocated in a relatively fixed proportion. Significant correlations between SO42−-S deposition and foliar S concentration, S cycling, and the molar ratio of S:N in foliage suggest that sulfate deposition has altered the uptake and cycling of S in northern hardwood forests of the Great Lakes region.

Welfare Assessment Tools in Zoos: From Theory to Practice

2021 ◽  
Author(s):  
Narelle Jones ◽  
Sally Sherwen ◽  
Rachel Robbins ◽  
David McLelland ◽  
Alexandra Whittaker
Keyword(s):  
Assessment Tools ◽  
Review Of The Literature ◽  
Comprehensive Review ◽  
Welfare Assessment ◽  
Theory To Practice ◽  
Zoo Animals ◽  
Specific Assessment ◽  
Scoring Schemes ◽  
Species Specific ◽  
Over Time

Zoos are increasingly putting in place formalized animal welfare assessment programs to allow monitoring of welfare over time, as well as to aid in resource prioritization. These programs tend to rely on assessment tools that incorporate resource-based and observational animal- focused measures since it is rarely feasible to obtain measures of physiology in zoo-housed animals. A range of assessment tools are available which commonly have a basis in the Five Domains framework. A comprehensive review of the literature was conducted to bring together recent studies examining welfare assessment methods in zoo animals. A summary of these methods is provided with advantages and limitations of the approach es presented. We then highlight practical considerations with respect to implementation of these tools into practice, for example scoring schemes, weighting of criteria, and innate animal factors for consideration. It is concluded that would be value in standardizing guidelines for development of welfare assessment tools since zoo accreditation bodies rarely prescribe these. There is also a need to develop taxon or species- specific assessment tools to inform welfare management.

Effects of nitrogen fertilizer, plant population and irrigation on sugar beet: II. Nutrient concentration and uptake

1971 ◽  
Vol 76 (2) ◽  
pp. 269-275 ◽  
Author(s):  
A. P. Draycott ◽  
M. J. Durrant
Keyword(s):  
Sugar Beet ◽  
Nitrogen Fertilizer ◽  
Nutrient Concentration ◽  
Field Experiments ◽  
Nitrogen Concentration ◽  
Plant Size ◽  
Plant Population ◽  
Sugar Yield ◽  
Phosphorus Concentration ◽  
Wide Range

SUMMARYThe concentration of nitrogen, phosphorus, potassium, sodium, calcium and magnesium was measured in the dry matter of sugar beet from four field experiments (1966–9). All combinations of four amounts of nitrogen fertilizer (0–1·8 cwt/acre), four plant populations (8800–54000 plants/acre) and irrigation were tested, which gave a wide range of plant size and yield. Nutrient concentration and uptake by the crop were also greatly affected by the treatments.Nitrogen fertilizer and irrigation increased uptake of nitrogen by the crop but increasing the plant population had little effect on uptake and decreased the concentration of nitrogen. Sugar yield was related to the total nitrogen concentration in tops and roots and to uptake. There were optimal values of nitrogen concentration for maximal sugar yield, but the optima were greatly affected by plant population. Leaf colour was a good guide to nitrogen concentration.Phosphorus concentration was affected little by the treatments but cation concentrations were greatly affected. In general, uptake of all the elements was increased by all treatments – the exception was sodium, which decreased as the plant population increased but this was balanced to somo extent by increased potassium uptake.

Long-term impact of liming on growth and vigor of northern hardwoods

2011 ◽  
Vol 41 (6) ◽  
pp. 1295-1307 ◽  
Author(s):  
Robert P. Long ◽  
Stephen B. Horsley ◽  
Thomas J. Hall
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Keystone Species ◽  
Basal Area ◽  
Fagus Grandifolia ◽  
Northern Hardwood ◽  
Crown Health ◽  
Lime Application ◽  
Species Specific

Sugar maple (Acer saccharum Marsh.) is a keystone species in the northern hardwood forest, and decline episodes have negatively affected the growth and health of sugar maple in portions of its range over the past 50+ years. Crown health, growth, survival, and flower and seed production of sugar maple were negatively affected by a widespread decline event in the mid-1980s on the unglaciated Allegheny Plateau in northern Pennsylvania. A long-term liming study was initiated in 1985 to evaluate responses to a one-time application of 22.4 Mg·ha–1 of dolomitic limestone in four northern hardwood stands. Over the 23-year period ending in 2008, sugar maple basal area increment (BAINC) increased significantly (P ≤ 0.05) in limed plots from 1995 through 2008, whereas American beech (Fagus grandifolia Ehrh.) BAINC was unaffected. For black cherry (Prunus serotina Ehrh.), the third principal overstory species, BAINC and survival were reduced in limed plots compared with unlimed plots. Foliar Ca and Mg remained significantly higher in sugar maple foliage sampled 21 years after lime application, showing persistence of the lime effect. These results show long-term species-specific responses to lime application.

scholarly journals Optimal Nutrient Concentration Ranges of ‘Hass’ Avocado Cauliflower Stage Inflorescences—Potential Diagnostic Tool to Optimize Tree Nutrient Status and Increase Yield

HortScience ◽  
2017 ◽  
Vol 52 (12) ◽  
pp. 1707-1715 ◽  
Author(s):  
Salvatore Campisi-Pinto ◽  
Yusheng Zheng ◽  
Philippe E. Rolshausen ◽  
David E. Crowley ◽  
Ben Faber ◽  
...  
Keyword(s):  
Nutrient Concentration ◽  
Fruit Set ◽  
Fruit Size ◽  
Nutrient Status ◽  
Persea Americana ◽  
Nutrient Concentrations ◽  
Full Bloom ◽  
Nutrient Analysis ◽  
Tree Phenology ◽  
Hass Avocado

Optimizing ‘Hass’ avocado (Persea americana Mill.) tree nutrient status is essential for maximizing productivity. Leaf nutrient analysis is used to guide avocado fertilization to maintain tree nutrition. The goal of this research was to identify a ‘Hass’ avocado tissue with nutrient concentrations predictive of yields greater than 40 kg of fruit per tree. This threshold was specified to assist the California avocado industry to increase yields to ≈11,200 kg·ha−1. Nutrient concentrations of cauliflower stage inflorescences (CSI) collected in March proved better predictors of yield than inflorescences collected at full bloom (FBI) in April, fruit pedicels (FP) collected at five different stages of avocado tree phenology from the end of fruit set in June through April the following spring when mature fruit enter a second period of exponential growth, or 6-month-old spring flush leaves (LF) from nonbearing vegetative shoots collected in September (California avocado industry standard). For CSI tissue, concentrations of seven nutrients, nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), sulfur (S), zinc (Zn), and copper (Cu) were predictive of trees producing greater than 40 kg of fruit annually. Conditional quantile sampling and frequency analysis were used to identify optimum nutrient concentration ranges (ONCR) for each nutrient. Optimum ratios between nutrient concentrations and yields greater than 40 kg per tree were also derived. The high nutrient concentrations characterizing CSI tissue suggest current fertilization practices (timing or amounts) might be causing nutrient imbalances at this stage of avocado tree phenology that are limiting productivity, a possibility that warrants further investigation. Because CSI samples can be collected 4–6 weeks before full bloom, nutritional problems can be addressed before they affect flower retention and fruit set to increase current crop yield, fruit size, and quality. Thus, CSI nutrient analysis warrants further research as a potential supplemental or alternative tool for diagnosing ‘Hass’ avocado tree nutrient status and increasing yield.

Deflighting zoo birds and its welfare considerations

2020 ◽  
Vol 29 (1) ◽  
pp. 69-80 ◽  
Author(s):  
L Reese ◽  
M Ladwig-Wiegard ◽  
L von Fersen ◽  
G Haase ◽  
H Will ◽  
...  
Keyword(s):  
Public Interest ◽  
Surgical Techniques ◽  
Bird Species ◽  
Scientific Data ◽  
Evidence Based ◽  
Specific Level ◽  
Welfare Implications ◽  
Reduce Risk ◽  
Species Specific ◽  
Over Time

For over a century the practice of deflighting has taken place in zoological collections in order to ensure birds remain in open-topped enclosures. Over time, efforts have been made to improve or develop new (surgical) techniques, reduce risk of complications during deflighting and minimise stress and pain during the procedure. However, increased public interest in issues of animal welfare has coincided with a questioning of the practice of removing a birds ability to fly. The ensuing debate, which continues to progress among a variety of differing stakeholders, has led to various legislative adjustments across a number of countries. Despite significant legislation, the dialogue has been both subjective and highly emotive. A plethora of opinions exist as to why deflighting should be outlawed, why it is necessary, or how it has the potential to improve a birds living conditions. However, most are based on assumption or issues unrelated to welfare. To the authors knowledge, to date, no scientific data have been published on the welfare implications of deflighting for the commonly deflighted bird species, such as waterfowl, flamingos (Phoenicopteridae), pelicans (Pelecanidae), storks (Ciconiidae), cranes (Gruidae) and herons (Ardeidae). The aim of this study is to present an overview of the relevance of deflighting to zoo husbandry, the species primarily affected, the techniques currently in use, the legality in differing countries and the extent of scientific knowledge as regards potential ethological and welfare concerns. An urgent need for evidence-based studies is highlighted, to further inform this practice at a species-specific level.

Spatial ecology of the Mariana Crow Corvus kubaryi: Implications for management strategies

2018 ◽  
Vol 29 (4) ◽  
pp. 527-541 ◽  
Author(s):  
SARAH K. FAEGRE ◽  
LINDSEY NIETMANN ◽  
DYLAN HUBL ◽  
JAMES C. HA ◽  
RENEE R. HA
Keyword(s):  
Home Range ◽  
Spatial Ecology ◽  
Large Scale ◽  
Life Stage ◽  
Management Strategies ◽  
Home Ranges ◽  
Spatial Behaviour ◽  
Island Endemic ◽  
Species Specific ◽  
Over Time

SummaryKnowledge of species-specific spatial ecology is critical for applying appropriate management strategies to maximise conservation outcomes. We used radio-telemetry to describe spatial behaviour of the critically endangered, island-endemic Mariana Crow Corvus kubaryi. To determine whether management strategies should reflect life stage, we measured the home ranges and daily movements of 22 Mariana Crows. Fledgling mobility was low during the first 31 days post-fledging and effects of age (fledgling or sub-adult) and time (months post-fledging or post-dispersal) were often driven entirely by this period. After controlling for reduced fledgling mobility, cumulative home range size increased over time for both age classes and was, on average, more than twice the area for sub-adults than fledglings. Sub-adults also tended to make longer daily movements than fledglings. Non-cumulative, monthly home range areas did not increase over time but the average overlap in home range area between consecutive months was only 63%, suggesting large shifts in space use each month. These results highlight the dynamic nature of Mariana Crow home ranges and suggest that large-scale management efforts are critical for protecting both breeding and non-breeding individuals. The application of the traditional home range concept to Mariana Crows and other wide-ranging passerine birds may result in sub-optimal management strategies. Instead, we recommend that the spatial and temporal scale of conservation efforts be informed by species-specific spatial behaviour across all relevant life stages.

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