scholarly journals Inflated population density of island antechinus: a case of allochthonous marine inputs leading to increased food availability?

2012 ◽  
Vol 60 (5) ◽  
pp. 343 ◽  
Author(s):  
M. G. Sale ◽  
J. P. Y. Arnould
Keyword(s):  
Food Availability ◽  
Soil Nutrient ◽  
Growth Period ◽  
Food Resources ◽  
Animal Populations ◽  
Colonial Seabirds ◽  
Increase Productivity ◽  
Food Subsidies ◽  
Marine Food ◽  
Island Habitats

Resource availability and other processes that affect maintenance, growth and decline of animal populations are central to ecology and conservation. This study quantified features indicative of population fitness and the availability of food resources for island and mainland populations of an insectivorous marsupial, the swamp antechinus (Antechinus minimus). The aim of the study was to test the hypothesis that colonial seabirds increase productivity of island habitats, ultimately providing greater food resources. The study found that antechinus biomass density was 4–13 times greater on the island site compared with the mainland site and was associated with higher recapture rates, suggesting that more individuals were surviving on the island during spring and summer months. An index of antechinus food availability (abundance and biomass of invertebrates) was also higher on the island site. Island antechinus also accessed marine food subsidies, in the form of seabird carrion, during the energetically demanding post-weaning growth period in spring and summer. Furthermore, based on soil nutrient and stable isotope analyses, there was strong evidence of nutrient enrichment from marine sources in the island ecosystem, commonly linked to increased productivity. Therefore, greater antechinus biomass and abundance on offshore islands are likely to be, in part, due to greater survival caused by higher availability of food resources.

Pre-Design Ocean Outfall Studies

1986 ◽  
Vol 18 (11) ◽  
pp. 105-110
Author(s):  
Willard Bascom
Keyword(s):  
Developing Countries ◽  
Environmental Studies ◽  
Food Resources ◽  
Biological Data ◽  
Limited Resources ◽  
High Tech ◽  
Minimal Cost ◽  
Marine Food ◽  
Ocean Outfall

This paper is intended to provide guidance to persons in developing countries who are responsible for making ocean outfall studies but have limited resources. It consists mainly of practical suggestions based on the author's experience about what measurements are needed to obtain useful information and how to make them at minimal cost. Thoughtfulness in planning work that will produce useful answers is favored over pseudo-high-tech environmental studies. Some opinions are presented about the enhancement of marine food resources by outfalls and about collecting biological data as a defense against possible criticism. The special conditions that may exist in enclosed bays and estuaries are not specifically addressed in this paper.

Modelling nutrient uptake: a possible indicator of phosphorus deficiency

Soil Research ◽  
1997 ◽  
Vol 35 (2) ◽  
pp. 313 ◽  
Author(s):  
D. S. Mendham ◽  
P. J. Smethurst ◽  
P. W. Moody ◽  
R. L. Aitken
Keyword(s):  
Nutrient Uptake ◽  
Phosphorus Deficiency ◽  
Soil Phosphorus ◽  
Soil Nutrient ◽  
Growth Period ◽  
Dry Weight ◽  
Root Surface ◽  
P Uptake ◽  
P Deficiency ◽  
Highly Correlated

An understanding of the processes controlling soil nutrient supply and plant uptake has led to process-based models that can predict nutrient uptake and the concentration gradient that develops at the root surface. By using this information, it may be possible to develop an indicator of soil phosphorus status based on the predicted uptake and/or concentration of phosphorus (P) at the root surface. To identify the potential for such a test, the relationships between model output and observed plant growth were examined using data from a published experiment. The experiment was initially designed to investigate the relationship between common indices of soil-available P and the growth of maize (Zea mays) in 26 surface soils from Queensland. There was a high correlation between observed and predicted P uptake, and between relative dry matter yield and predicted P uptake. The predicted concentration of P at the root surface was also highly correlated with P uptake and dry weight increase. It is hypothesised that the short growth period (25 days) was responsible for the high correlation between P uptake and measured soil solution P. The hypothesis that a predicted concentration of P at the root surface or predicted P uptake may be valuable indicators of P deficiency in the longer term still remains to be tested.

scholarly journals Impact of elevated temperature on rice productivity: A case of Lalitpur, Nepal

2016 ◽  
Vol 4 ◽  
pp. 19-22
Author(s):  
Ambika Ghimire ◽  
Yubak Dhoj G.C. ◽  
Binod Baniya
Keyword(s):  
Elevated Temperature ◽  
Oryza Sativa L ◽  
Abiotic Factors ◽  
Rice Variety ◽  
Soil Nutrient ◽  
Growth Period ◽  
Crop Productivity ◽  
Straw Yield ◽  
Important Crop ◽  
The Impact

Rice (Oryza sativa L.) is the second most important crop in the world after wheat and also the most important crop in Nepal. The production of rice is influenced by various biotic and abiotic factors. Temperature is the major constraint for the crop yield. The present experiment was conducted to study the impact of temperature on straw and crop productivity from June to October 2014. The experiment was conducted under temperature control chamber, in which temperature was elevated from the ambient level by 2ºC and 3ºC for the entire crop growth period. Grain and straw yield was measured using electronic weighing machine. Maturity of grain was 10 and 7 days earlier at elevated temperature by 3ºC and 2ºC respectively. Under similar condition of water depth, plant spacing, rice variety and soil nutrient, rise in temperature up to 2ºC is favorable for rice straw yield and crop productivity. Yield loss under elevated temperature by 3ºC is due to floret sterility. Further research on temperature resistance rice variety is necessary.

scholarly journals The effect of habitat degradation, season and gender on morphological parameters of lesser jerboas (Jaculus jaculus L.) in Kuwait

2012 ◽  
Vol 35 (1) ◽  
pp. 119-124
Author(s):  
M. Al–Mutairi ◽  
◽  
F. Mata ◽  
R. Bhuller ◽  
◽  
...  
Keyword(s):  
Habitat Degradation ◽  
Tail Length ◽  
Food Resources ◽  
Arid Environments ◽  
Morphological Parameters ◽  
Escape Behaviour ◽  
Animal Populations ◽  
And Gender

Arid environments suffer anthropogenic interference causing habitat degradation. This degradation can influence animal populations. We randomly captured a total of 198 lesser jerboas Jaculus jaculus in three seasons (autumn, spring and summer) in two relatively close areas (intact and degraded). All animals were sexed, and weight, body and tail length, and thigh thickness were taken. We found significant differences in weight (p < 0.001), which was lower in summer (p < 0.05) when fewer food resources were available. Thigh thickness was greater in the intact habitat (p < 0.01), explained by the greater amount of food resources and also by the higher numbers of predators in this area, prompting escape behaviour. Females in the intact area were heavier and had longer bodies and tails. This was related to greater availability of time for mothers to search for food in this area.

scholarly journals Competing pressures on populations: long-term dynamics of food availability, food quality, disease, stress and animal abundance

2015 ◽  
Vol 370 (1669) ◽  
pp. 20140112 ◽  
Author(s):  
Colin A. Chapman ◽  
Valérie A. M. Schoof ◽  
Tyler R. Bonnell ◽  
Jan F. Gogarten ◽  
Sophie Calmé
Keyword(s):  
Food Availability ◽  
Physiological Stress ◽  
Ecological Factors ◽  
Forest Composition ◽  
Forest Fragments ◽  
Red Colobus ◽  
Red Colobus Monkeys ◽  
Animal Populations ◽  
Quality Diet

Despite strong links between sociality and fitness that ultimately affect the size of animal populations, the particular social and ecological factors that lead to endangerment are not well understood. Here, we synthesize approximately 25 years of data and present new analyses that highlight dynamics in forest composition, food availability, the nutritional quality of food, disease, physiological stress and population size of endangered folivorous red colobus monkeys ( Procolobus rufomitratus ). There is a decline in the quality of leaves 15 and 30 years following two previous studies in an undisturbed area of forest. The consumption of a low-quality diet in one month was associated with higher glucocorticoid levels in the subsequent month and stress levels in groups living in degraded forest fragments where diet was poor was more than twice those in forest groups. In contrast, forest composition has changed and when red colobus food availability was weighted by the protein-to-fibre ratio, which we have shown positively predicts folivore biomass, there was an increase in the availability of high-quality trees. Despite these changing social and ecological factors, the abundance of red colobus has remained stable, possibly through a combination of increasing group size and behavioural flexibility.

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