We present a mathematical model that studies and simulates the interconnection between energetic and ecological aspects of bird migration. By comparing model predictions with experimental data, we show that it can be used to assess the impact of changing environmental conditions in breeding, wintering, and stop-over sites on migratory success. We relate in particular to the European white stork (Ciconia ciconia) and its Eastern migration route and discuss questions concerning the timing, stopover, and feeding behavior en route. Opinions concerning the importance of resource availability and resource quality en route are divided. Whereas some studies have shown that storks gain weight in the wintering site, but almost do not feed en route, others stress the importance of the quality of stop-over locations. We address these questions and simulate the development of stork populations for changing environmental conditions. We demonstrate that resource availability and competition for breeding sites are crucial factors determining the timing of spring migration and the length of stop-over periods. Analyzing the robustness of migration strategies with respect to changing environmental conditions, we show that birds will shorten their stay in stop-over places of poor resource availability rather than prolonging it in the attempt to gain time for accumulating fat reserves.

Sabine St&#xf6;cker-Segre

Daniel Weihs

Impact of Environmental Changes on Migratory Bird Survival

Aquatic environments are being modified by anthropogenic activities regarding their biological, physical, and chemical conditions; even pristine aquatic ecosystems can be threatened. This study focused on the biological monitoring of Maroaga Stream&#x2014;a first order stream located in an Environmental Protection Area in the Amazon using the Biological Monitoring Working Party (BMWP) Score System. The BMWP Score System revealed that the Maroaga Stream was a Class I stream (score of 138 points), indicating clean or not significantly altered water quality. The results suggest the adequate environmental conditions and ecological responses of the Maroaga Stream.

Christiane Brito Uherek

Fernando Bernardo Pinto Gouveia

Biological Monitoring Using Macroinvertebrates as Bioindicators of Water Quality of Maroaga Stream in the Maroaga Cave System, Presidente Figueiredo, Amazon, Brazil

The need for information on Grey Parrot distribution and vegetation associations for informed management and policy decisions was the basis for this study. A nationwide survey of the Grey Parrot population and habitat status was carried out, using questionnaire and point count methods. From the results, the extent of the contemporary range of the parrots was restricted to Southern Cameroon, which harbours the rainforest.  Regional parrot population means ranged from 3,487 parrots in the Littoral to 1,351,275 parrots in the East Regions. The extent of the contemporary range as a percentage of the whole country was 25.4&#x25; and as a percentage of the regions with rainforest was 44.5&#x25;. The historic range of the bird has been reduced by over 55.5&#x25;.  Estimated percentage of forest lost per region ranged from 20.4&#x25; in the Centre to 57.1&#x25; in the East and South Regions. At a global level, Cameroon contributed 9&#x25; to the total extent of the range of the Grey Parrot in Africa. The range is increasingly fragmented, contracted, and lost through land-based socioeconomic activities. These degradation pressures on the range called for urgent conservation considerations for long-term survival of the parrot species and its associated biodiversity in Cameroon.

Simon A. Tamungang

Robert A. Cheke

Gilbert Z. Mofor

Richard N. Tamungang

Fritz T. Oben

Conservation Concern for the Deteriorating Geographical Range of the Grey Parrot in Cameroon

Selenium is an essential trace element for animal and human beings. Despite the importance of insects in most ecosystems and their significant contribution to the biological cycling of trace elements due to high abundance, population productivity, and diverse ecosystem functions, surprisingly little information is available on selenium bioaccumulation by these arthropods. This review considers selenium essentiality and toxicity to insects as well as insects&#x2019; contribution to selenium trophic transfer through the food chains. Data on Se accumulation by insects of the Dniester River Valley with no anthropogenic Se loading reveal typically low Se content in necrophagous insects compared to predators and herbivores and seasonal variations in Se accumulation.

Nadezhda Golubkina

Sergey Sheshnitsan

Marina Kapitalchuk

Ecological Importance of Insects in Selenium Biogenic Cycling

This study was aimed at determining the performance of some indices and community attributes frequently used to assess river quality and test the role of macroinvertebrate taxa richness as element of bioindication in several coastal tropical streams of western Esmeraldas (Ecuador). In addition, a macroinvertebrate taxon list of this region was provided for the first time. Thirteen sampled points distributed across nine streams were selected for this study and nineteen parameters and attributes of bioindication were tested. The differences between nonimpact and impact places were evaluated mainly using one-way analysis of variance. Jackknife 2 and Clench were used to estimate the regional richness and the quality of the inventory, respectively. Seventy taxa (principally genus and family) of the main groups of macroinvertebrates were collected. Measured richness and family richness were the best metric followed by  Biological Monitoring Working Party/Colombia (BMWP/Col), Odonata richness, Shannon-Weiner, and EPT richness (Ephemeroptera&#x2009;+&#x2009;Plecoptera&#x2009;+&#x2009;Trichoptera) indices. Only a slight right trend (Ephemeroptera, Trichoptera, and Chironomidae attributes) or incorrect performances (Average Score Per Taxon (ASPT) and &#x25; EPT) were showed by frequently used metrics. Finally, several recommendations were made about taxonomic level used, the ranks of quality of taxa richness, and the effort-results relationship in the field of bioindication.

Carlos Mart&#xed;nez-Sanz

Sara Mar&#xed;a Puente-Garc&#xed;a

Eduardo Rodolfo Rebolledo

Pedro Jim&#xe9;nez-Prado

Macroinvertebrate Richness Importance in Coastal Tropical Streams of Esmeraldas (Ecuador) and Its Use and Implications in Environmental Management Procedures

This research examines the diversity-productivity relationship in a semiarid scrubland, initially under late successional conditions and subsequently under early successional conditions created by experimental clearing, to explore the roles that productivity and stochastic mortality play in species exclusion in this environment. A total of fifteen plots were studied by measuring environmental conditions and biomass components of shrubs and seedlings. These stands were distributed along a productivity gradient across five different landforms. A hypothesis about the stochastic self-thinning mortality model along the gradient was evaluated with the diversity-productivity-environment data. The diversity-productivity relationship was linear and reversed between the early and late succession stages. The hypothesis of stochastic mortality of species exclusion was rejected in the early stages of succession and partially accepted in the mature stage of succession. Species exclusion was negatively related to productivity gradients, suggesting that strong interspecific competition occurs in high productivity plots and that a larger number of species can survive in higher abiotic stress landscapes. Further research is needed to understand the temporal and spatial variations of the ecological interactions that shape this plant community.

Jose Navar

F. de Jesus Rodriguez-Flores

Pedro A. Dominguez-Calleros

Gustavo Perez-Verdin

Diversity-Productivity Relationship in the Northeastern Tamaulipan Thornscrub Forest of Mexico

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International Journal of Ecology publishes articles in all areas of ecological sciences, The journal encourages the submission of big data studies, either presenting novel findings from large datasets or demonstrating new analytical techniques.

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International Journal of Ecology - Table of contents 2014

International Journal of Ecology | Hindawi

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International Journal of Ecology publishes articles in all areas of ecological sciences, The journal encourages the submission of big data studies, either presenting novel findings from large datasets or demonstrating new analytical techniques.

International Journal of Ecology