Testing the effects of nutrient additions on mudflat macroinfaunal assemblages in the presence and absence of shorebird predators

2003 ◽  
Vol 54 (7) ◽  
pp. 859 ◽  
Author(s):  
Liz Morris ◽  
Michael J. Keough
Keyword(s):  
Strong Interaction ◽  
Nutrient Loading ◽  
Nutrient Status ◽  
Migratory Bird ◽  
High Dose ◽  
Intertidal Mudflat ◽  
Bird Populations ◽  
Nutrient Additions ◽  
Nearshore Environments ◽  
High Nutrient

An issue that is of increasing concern worldwide relates to the possibility that areas subject to conservation agreements, owing to the resident and migratory bird populations they support, will be adversely affected by attempts to reduce organic inputs into nearshore environments. In the present study, we investigated the effects of nutrient additions and shorebird exclusion on the infaunal assemblages of an intertidal mudflat. Where responses to nutrient additions were observed they only occurred in the high-dose treatments, indicating that a high nutrient loading is required before infaunal responses are initiated at this site. There was no evidence to support the idea that nutrient additions would only stimulate macroinfaunal assemblages where shorebird foraging was reduced. Instead, nutrient additions were detectable separately from any effects of shorebird predation and, contrary to expectations, appeared to be of more importance than shorebird predation in this environment. There was also no evidence to suggest that shorebird predation has a strong interaction with the infaunal prey assemblage and, although further studies will be needed to support this statement, it is possible that moderate changes in nutrient status will not impact on the shorebird populations at this site.

A neonicotinoid insecticide reduces fueling and delays migration in songbirds

Science ◽  
2019 ◽  
Vol 365 (6458) ◽  
pp. 1177-1180 ◽  
Author(s):  
Margaret L. Eng ◽  
Bridget J. M. Stutchbury ◽  
Christy A. Morrissey
Keyword(s):  
Pesticide Exposure ◽  
Radio Telemetry ◽  
Migratory Bird ◽  
Adverse Outcomes ◽  
High Dose ◽  
Rapid Reduction ◽  
Bird Populations ◽  
Survival And Reproduction ◽  
Carry Over ◽  
Migrating Birds

Neonicotinoids are neurotoxic insecticides widely used as seed treatments, but little is known of their effects on migrating birds that forage in agricultural areas. We tracked the migratory movements of imidacloprid-exposed songbirds at a landscape scale using a combination of experimental dosing and automated radio telemetry. Ingestion of field-realistic quantities of imidacloprid (1.2 or 3.9 milligrams per kilogram body mass) by white-crowned sparrows (Zonotrichia leucophrys) during migratory stopover caused a rapid reduction in food consumption, mass, and fat and significantly affected their probability of departure. Birds in the high-dose treatment stayed a median of 3.5 days longer at the site of capture after exposure as compared with controls, likely to regain fuel stores or recover from intoxication. Migration delays can carry over to affect survival and reproduction; thus, these results confirm a link between sublethal pesticide exposure and adverse outcomes for migratory bird populations.

Impact of hydro-thermal conditions on the spatio-temporal patterns of migratory bird populations

2017 ◽  
Vol 37 (8) ◽  
Author(s):  
赵红梅 ZHAO Hongmei ◽  
陈晓玲 CHEN Xiaoling ◽  
徐冰 XU Bing ◽  
冯炼 FENG Lian
Keyword(s):  
Thermal Conditions ◽  
Temporal Patterns ◽  
Migratory Bird ◽  
Bird Populations ◽  
Spatio Temporal

scholarly journals The implications of mid‐latitude climate extremes for North American migratory bird populations

Ecosphere ◽  
2016 ◽  
Vol 7 (3) ◽  
Author(s):  
Frank A. La Sorte ◽  
Wesley M. Hochachka ◽  
Andrew Farnsworth ◽  
André A. Dhondt ◽  
Daniel Sheldon
Keyword(s):  
North American ◽  
Climate Extremes ◽  
Migratory Bird ◽  
Bird Populations

scholarly journals Seasonal changes in the altitudinal distribution of nocturnally migrating birds during autumn migration

2015 ◽  
Vol 2 (12) ◽  
pp. 150347 ◽  
Author(s):  
Frank A. La Sorte ◽  
Wesley M. Hochachka ◽  
Andrew Farnsworth ◽  
Daniel Sheldon ◽  
Benjamin M. Van Doren ◽  
...  
Keyword(s):  
Migratory Birds ◽  
Global Climate ◽  
Polar Front ◽  
Migratory Bird ◽  
Atmospheric Conditions ◽  
Altitudinal Distribution ◽  
Long Distance ◽  
Bird Populations ◽  
Intermediate Distance ◽  
Migrating Birds

Wind plays a significant role in the flight altitudes selected by nocturnally migrating birds. At mid-latitudes in the Northern Hemisphere, atmospheric conditions are dictated by the polar-front jet stream, whose amplitude increases in the autumn. One consequence for migratory birds is that the region’s prevailing westerly winds become progressively stronger at higher migration altitudes. We expect this seasonality in wind speed to result in migrants occupying progressively lower flight altitudes, which we test using density estimates of nocturnal migrants at 100 m altitudinal intervals from 12 weather surveillance radar stations located in the northeastern USA. Contrary to our expectations, median migration altitudes deviated little across the season, and the variance was lower during the middle of the season and higher during the beginning and especially the end of the season. Early-season migrants included small- to intermediate-sized long-distance migrants in the orders Charadriiformes and Passeriformes, and late-season migrants included large-bodied and intermediate-distance migrants in the order Anseriformes. Therefore, seasonality in the composition of migratory species, and related variation in migration strategies and behaviours, resulted in a convex–concave bounded distribution of migration altitudes. Our results provide a basis for assessing the implications for migratory bird populations of changes in mid-latitude atmospheric conditions probably occurring under global climate change.

scholarly journals Aplikasi Penderiaan Jauh atau Remote Sensing dalam Pemodelan Pengaruh Iklim terhadap Taburan Burung Hijrah Di Hutan Paya Laut Matang, Perak

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Azimah Abd Rahman
Keyword(s):  
Remote Sensing ◽  
Habitat Selection ◽  
Mangrove Forest ◽  
Migratory Birds ◽  
Climate Modeling ◽  
Migratory Bird ◽  
Bird Populations ◽  
Alternative Habitat ◽  
The Future ◽  
Selection Of

Climate changes especially temperature and rainfall effect the habitat selection of bird migration in mangrove area to get some food and temporary stopover. The increase and decrease of temperature and rainfall is varies between upstream to downstream. This research was done to prove that temperature and rainfall are uneven in some area even in same boundary that can give impact in habitat selection of migratory birds. This research was concern around Matang Mangrove Forest, Perak that already familiar as focal area for migratory birds. Remote Sensing application was used in this research through use of ERDAS Imagine 8.5 which is based on pixels. This application helps to model the relationship between climate, namely temperature and rainfall with distribution density of migratory birds around the study area. Climate modeling was conducted to predict the distribution of migratory bird populations in the future due to changes in temperature and rainfall over a period of 5 years and 20 years. The results of this study showed a decrease in the population of migratory birds by 6.4% for a period of 5 years and a decrease to 7.5% for the last 20 years.  Sungai Sepetang and Sungai Selinsing shown that migratory bird populations decreased continuously after 20 years. However the Sangga Besar, Teluk Kertang, Temerlok, Pulau Pasir Hitam dan Sungai Tinggi area showed an increase in the arrival of migratory birds after 20 years.  This information analysis help the related agencies in manage and maintain the area around the Matang Mangrove Forest identified potential habitat for migratory birds in the future. In addition, through this study migratory bird monitoring can be carried out systematically on a wider scope without ignoring areas that strives to be the alternative habitat for migratory birds in the future.

scholarly journals Using benthic diatom assemblages to assess sedimentary nutrient status in Tri An reservoir, Dong Nai province, Vietnam

2021 ◽  
Vol 5 (2) ◽  
pp. first
Author(s):  
Yến Thị Hoàng Trần ◽  
Thái Thành Trần ◽  
Quảng Xuân Ngô ◽  
Hà Mạnh Bùi ◽  
Lưu Thanh Phạm
Keyword(s):  
Sediment Quality ◽  
Nutrient Status ◽  
Biological Indicators ◽  
Underground Water ◽  
Benthic Diatom ◽  
Diatom Assemblages ◽  
Nutrient Contents ◽  
High Nutrient ◽  
Nutritional Compounds

Tri An Reservoir plays an important role in the water supply for Dong Nai province and Ho Chi Minh city. It also contributes significantly to increase underground water reserves in the vicinity, especially in the dry season. However, recently, the increase of nutritional compounds in the lake has contributed to eutrophication, causing serious deterioration of the quality of the environment, creating conditions for microalgae to thrive. Therefore, this study aimed to evaluate and zoning the sediment quality of the Tri An reservoir based on using benthic diatom communities as biological indicators as an indicator tool. Sediment and algae samples were collected from 8 survey locations in the Ho Tri An area from March to August in 2019. The results showed that the dominance of several species belonging to the genera that prefer to live in nutrient-rich environment such as Navicula, Nitzschia. The TDI index indicated the sediment environment had high nutrient contents. Water quality in the lower section of the reservoir was classified from eutrophic (even hyper-eutrophic) status, particularly stations into the reservoir. Meanwhile, upstream and downstream sites had lower nutrient levels, mainly excessive phosphorus but still in eutrophic class. Additionally, the initial analysis results also revealed that NH4 +, TN, PO4 3􀀀 and DO played a major role to regulate the development of benthic diatom assemblages.

scholarly journals Ecosystem Entanglement and the Propagation of Nutrient-Driven Instability

2020 ◽  
Author(s):  
Kevin S. McCann ◽  
A.S MacDougall ◽  
G.F. Fussmann ◽  
C. Bieg ◽  
K. Cazelles ◽  
...  
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Nutrient Loading ◽  
Transport Theory ◽  
Nutrient Addition ◽  
Edible Plant ◽  
Nutrient Additions ◽  
Theoretical Synthesis ◽  
Human Modification ◽  
And Function

ABSTRACTAlmost 50 years ago, Michael Rosenzweig pointed out that nutrient addition can destabilize food webs, leading to loss of species and reduced ecosystem function through the paradox of enrichment. Around the same time, David Tilman demonstrated that increased nutrient loading would also be expected to cause competitive exclusion leading to deleterious changes in food web diversity. While both concepts have greatly illuminated general diversity-stability theory, we currently lack a coherent framework to predict how nutrients influence food web stability across a landscape. This is a vitally important gap in our understanding, given mounting evidence of serious ecological disruption arising from anthropogenic displacement of resources and organisms. Here, we combine contemporary theory on food webs and meta-ecosystems to show that nutrient additions are indeed expected to drive loss in stability and function in human-impacted regions. However, this loss in stability occurs not just from wild oscillations in population abundance, but more frequently from the complete loss of an equilibrium due to edible plant species being competitively excluded. In highly modified landscapes, spatial nutrient transport theory suggests that such instabilities can be amplified over vast distances from the sites of nutrient addition. Consistent with this theoretical synthesis, the empirical frequency of these distant propagating ecosystem imbalances appears to be growing. This synthesis of theory and empirical data suggests that human modification of the Earth’s ecological connectivity is “entangling” once distantly separated ecosystems, causing rapid, expansive, and costly nutrient-driven instabilities over vast areas of the planet. The corollary to this spatial nutrient theory, though -- akin to weak interaction theory from food web networks -- is that slow spatial nutrient pathways can be potent stabilizers by moderating flows across a landscape.

scholarly journals Quantifying and Mapping of Major, Secondary and Micronutrient Status of Tomato Growing Soils in Kolar District, Karnataka Using GIS and GPS Approach

2020 ◽  
pp. 14-27
Author(s):  
P. N. Siva Prasad ◽  
C. T. Subbarayappa ◽  
V. Ramamurthy ◽  
A. Sathish
Keyword(s):  
Spatial Variability ◽  
Soil Fertility ◽  
Crop Production ◽  
Nutrient Management ◽  
Nutrient Status ◽  
Available Nitrogen ◽  
Micronutrient Status ◽  
High Nutrient ◽  
Nutrient Index ◽  
The Impact

Assessment of land use-induced changes in soil properties is essential for addressing issues of spatial variability in soil fertility and sustainable land productivity. In view of this, a study was conducted to assess the impact of spatial variability on physicochemical properties, macro and micro nutrient status of 75 farmers fields of tomato growing areas of Kolar district, Karnataka. Arc Map with spatial analyst function of Arc GIS software was used to prepare soil fertility maps, which would act as an important tool for soil as well as nutrient management for sustainable crop production by using Global Positioning System coordinates. The results revealed that the soils under investigation were acidic to alkaline in reaction (pH 4.41 to 8.13), mostly non saline and low to high in organic carbon status (0.53 to 1.95%). Available nitrogen, phosphorus, potassium and sulphur content varied from 150.53-348.10, 6.4 - 111.44, 147.18 - 916.61 and 12.29 - 103.8 kg ha-1. Exchangeable Ca, Mg are in the range of 2.5 – 14.2 and 1.2 – 6.6 C mol (p+) kg. The GIS-aided thematic maps with respect to available zinc, 6.67 (low), 21.33 (medium) and 72 (high) per cent samples were categorized, based on the existing critical limits. All the studied samples i.e., 100 per cent were high in copper content, 65.33, 30.67 and 4 per cent samples of Mn, 25.33, 32 and 42.67 per cent samples of Fe, were categorized as low, medium and high in nutrient status respectively. With respect to available boron 16.67 per cent was under low, 38.09 per cent was under medium and 45.24 per cent was under high nutrient status. The nutrient index (NI) of tomato growing areas of Kolar district revealed that N (1.19), manganese (1.39) and iron (1.29) were categorized as low, available boron (2.17) as medium and P (2.65), K (2.71), S (2.65) zinc (2.75), copper (3.0) as high nutrient index category.

scholarly journals Effect of Straw Biochar on Soil Properties and Wheat Production under Saline Water Irrigation

Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 457 ◽  
Author(s):  
Mingyi Huang ◽  
Zhanyu Zhang ◽  
Yaming Zhai ◽  
Peirong Lu ◽  
Chengli Zhu
Keyword(s):  
Saline Water ◽  
Eastern China ◽  
Sustainable Use ◽  
Nutrient Status ◽  
Soil Salinization ◽  
Growth And Yield ◽  
High Dose ◽  
N Availability ◽  
Wheat Production ◽  
Saline Water Irrigation

Use of saline water for irrigation is essential to mitigate increasing agricultural water demands in arid and semi-arid regions. The objective of this study is to address the potential of using straw biochar as a soil amendment to promote wheat production under saline water irrigation. A field experiment was conducted in a clay loam soil from eastern China during 2016/2017 and 2017/2018 winter wheat season. There were five treatments: freshwater irrigation (0.3 dS m−1), saline water irrigation (10 dS m−1), saline water irrigation (10 dS m−1) combined with biochar of 10, 20, 30 t ha−1. Saline water irrigation alone caused soil salinization and decreased wheat growth and yield. The incorporation of biochar decreased soil bulk density by 5.5%–11.6% and increased permeability by 35.4%–49.5%, and improved soil nutrient status. Biochar also reduced soil sodium adsorption ratio by 25.7%–32.6% under saline water irrigation. Furthermore, biochar alleviated salt stress by maintaining higher leaf relative water content and lower Na+/K+ ratio, and further enhanced photosynthesis and relieved leaf senescence during reproductive stages, leading to better grain formation. Compared to saline water irrigation alone, biochar application of 10 and 20 t ha−1 significantly increased wheat grain yield by 8.6 and 8.4%, respectively. High dose of biochar might increase soil salinity and limit N availability. In the study, biochar amendment at 10 t ha−1 would be a proper practice at least over two years to facilitate saline water irrigation for wheat production. Long-term studies are recommended to advance the understanding of the sustainable use of straw biochar.

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