Does hypoxia reduce habitat quality for Lake Erie walleye (Sander vitreus)? A bioenergetics perspective

2011 ◽  
Vol 68 (5) ◽  
pp. 857-879 ◽  
Author(s):  
Stephen B. Brandt ◽  
Marco Costantini ◽  
Sarah Kolesar ◽  
Stuart A. Ludsin ◽  
Doran M. Mason ◽  
...  
Keyword(s):  
Habitat Quality ◽  
Lake Erie ◽  
Prey Availability ◽  
Spatial Arrangement ◽  
Spatially Explicit ◽  
Sander Vitreus ◽  
Light Conditions ◽  
The Impact ◽  
Favorable Temperature ◽  
East West

In Lake Erie, the duration and extent of hypoxia (dissolved oxygen (DO)  ≤ 2 mg·L–1) has increased in recent years, yet little is known on the corresponding impact on its fish, particularly the highly valued walleye ( Sander vitreus ) fishery. Here, we quantified the impact of hypoxia on walleye habitat quality, using a spatially explicit growth rate potential (GRP) modeling approach, which integrates the spatial arrangement of biological (prey availability) and environmental (DO, temperature, irradiance) measures. Data were collected along two types of transects: 60 km north–south transects (each sampled once during day and night) and 5 km east–west transects (sampled every 4 h for 24 h) during August (pre-hypoxia), September (peak-hypoxia), and October (post-hypoxia) 2005. Overall, the average monthly amount of high quality habitat (GRP > 0 g·g–1·day–1) for walleye declined slightly with hypoxia (<2.0%); however, hypoxia appeared to enhance habitat quality by concentrating prey in favorable temperature, DO, and light conditions. In September, percentages of walleye growth rates were at the upper end of the range, much more so than during August or October. Although an understanding of walleye distributions, foraging, and growth in relation to hypoxia is needed, our results do not suggest that hypoxia is negatively influencing walleye through reduced habitat quality.

scholarly journals Assessing population collapse of Drupella spp. (Mollusca: Gastropoda) 2 years after a coral bleaching event in the Republic of Maldives

Hydrobiologia ◽  
2021 ◽  
Author(s):  
L. Saponari ◽  
I. Dehnert ◽  
P. Galli ◽  
S. Montano
Keyword(s):  
Coral Bleaching ◽  
Prey Availability ◽  
Coral Cover ◽  
Environmental Data ◽  
High Plasticity ◽  
Bleaching Event ◽  
Coral Recovery ◽  
The Republic ◽  
The Impact ◽  
Line Intercept

AbstractCorallivory causes considerable damage to coral reefs and can exacerbate other disturbances. Among coral predators, Drupella spp. are considered as delayer of coral recovery in the Republic of Maldives, although little information is available on their ecology. Thus, we aimed to assess their population structure, feeding behaviour and spatial distribution around 2 years after a coral bleaching event in 2016. Biological and environmental data were collected using belt and line intercept transects in six shallow reefs in Maldives. The snails occurred in aggregations with a maximum of 62 individuals and exhibited a preference for branching corals. Yet, the gastropods showed a high plasticity in adapting feeding preferences to prey availability. Drupella spp. were homogenously distributed in the study area with an average of 9.04 ± 19.72 ind/200 m2. However, their occurrence was significantly different at the reef scale with the highest densities found in locations with higher coral cover. The impact of Drupella spp. appeared to be minimal with the population suffering from the loss of coral cover. We suggest that monitoring programs collect temporal- and spatial-scale data on non-outbreaking populations or non-aggregating populations to understand the dynamics of predation related to the co-occurrence of anthropogenic and natural impacts.

scholarly journals Assessing Habitat Vulnerability and Loss of Naturalness: Applying the GLOBIO3 Model in the Czech Republic

2021 ◽  
Vol 13 (10) ◽  
pp. 5355
Author(s):  
Vilém Pechanec ◽  
Ondřej Cudlín ◽  
Miloš Zapletal ◽  
Jan Purkyt ◽  
Lenka Štěrbová ◽  
...  
Keyword(s):  
Land Use ◽  
Czech Republic ◽  
Habitat Quality ◽  
Species Abundance ◽  
Biodiversity Loss ◽  
Infrastructure Development ◽  
Natural Habitats ◽  
The Czech Republic ◽  
New Equation ◽  
The Impact

Global and regional biodiversity loss is caused by several drivers including urban development, land use intensification, overexploitation of natural resources, environmental pollution, and climate change. The main aim of our study was to adapt the GLOBIO3 model to the conditions of the Czech Republic (CR) to assess loss of naturalness and biodiversity vulnerability at the habitat level on a detailed scale across the entire CR. An additional aim was to assess the main drivers affecting the biodiversity of habitat types. The GLOBIO3 model was adapted to CZ-GLOBIO by adapting global to local scales and using habitat quality and naturalness data instead of species occurrence data. The total mean species abundance (MSA) index of habitat quality, calculated from the spatial overlay of the four MSA indicators by our new equation, reached the value 0.62. The total value of MSA for natural and near-natural habitats was found to be affected mainly by infrastructure development and fragmentation. Simultaneously, intensity of land use change and atmospheric nitrogen deposition contributed primarily to the low total value of MSA for distant natural habitats. The CZ-GLOBIO model can be an important tool in political decision making to reduce the impact of the main drivers on habitat biodiversity in the CR.

scholarly journals Spatial Assessment of the Potential Impact of Infrastructure Development on Biodiversity Conservation in Lowland Nepal

2018 ◽  
Vol 7 (9) ◽  
pp. 365 ◽  
Author(s):  
Roshan Sharma ◽  
Bhagawat Rimal ◽  
Nigel Stork ◽  
Himlal Baral ◽  
Maheshwar Dhakal
Keyword(s):  
Protected Areas ◽  
Habitat Quality ◽  
Infrastructure Development ◽  
Remotely Sensed Data ◽  
Buffer Zones ◽  
Ecological Sites ◽  
Key Species ◽  
Potential Impact ◽  
Anthropogenic Threats ◽  
The Impact

Biodiversity is declining at an unprecedented rate with infrastructure development being one of the leading causes. New infrastructure, such as roads, provides new access and results in increased land clearing and wildlife hunting. A number of large infrastructure projects, including new roads and rail, are being planned in Nepal. We show the application of readily available remotely sensed data and geospatial tools to assess the potential impact of these future developments on habitat quality under three protection-level scenarios. Our findings reveal that there is currently large spatial heterogeneity in habitat quality across the landscape as a result of current anthropogenic threats, and that three areas in particular could have up to 40% reduction in habitat quality as a result of the planned infrastructure. Further research is required to determine more precisely the impact on key species. Strengthening protected areas and buffer zones will contribute to mitigating degradation to some degree, however, large areas of biologically significant areas outside protected areas will be affected without new controls. Our geographic information systems (GIS) based methodology could be used to conduct studies in data poor developing countries, where rapid infrastructure development across ecological sites are ongoing, in order to make society, policy makers, and development planners aware.

Lost in a Triangle: U.S.-Soviet Back-Channel Documents on the Japan Factor in Tripartite Diplomacy, 1969–1972

2013 ◽  
Vol 15 (2) ◽  
pp. 51-71 ◽  
Author(s):  
Vladislav Zubok
Keyword(s):  
National Security ◽  
The Other ◽  
Henry Kissinger ◽  
Major Powers ◽  
National Security Adviser ◽  
The Impact ◽  
East West

This article examines the impact of Japan on U.S.-Soviet relations during Richard Nixon's first term as U.S. president. Drawing heavily on recently declassified documents pertaining to back-channel negotiations between Nixon's national security adviser, Henry Kissinger, and Soviet Ambassador Anatolii Dobrynin, the article explains why no Soviet-Japanese rapprochement proved feasible even during the height of East-West détente. The enduring hostility was in contrast to the realignments of the other major powers during this period.

scholarly journals Identification of traffic accident risk-prone areas under low-light conditions

2015 ◽  
Vol 15 (9) ◽  
pp. 2059-2068 ◽  
Author(s):  
K. Ivan ◽  
I. Haidu ◽  
J. Benedek ◽  
S. M. Ciobanu
Keyword(s):  
Traffic Accident ◽  
Traffic Accidents ◽  
Pearson Correlation ◽  
Injury Rate ◽  
Spatial Relation ◽  
Accident Risk ◽  
Light Conditions ◽  
Low Light ◽  
The Impact ◽  
The City

Abstract. Besides other non-behavioural factors, low-light conditions significantly influence the frequency of traffic accidents in an urban environment. This paper intends to identify the impact of low-light conditions on traffic accidents in the city of Cluj-Napoca, Romania. The dependence degree between light and the number of traffic accidents was analysed using the Pearson correlation, and the relation between the spatial distribution of traffic accidents and the light conditions was determined by the frequency ratio model. The vulnerable areas within the city were identified based on the calculation of the injury rate for the 0.5 km2 areas uniformly distributed within the study area. The results show a strong linear correlation between the low-light conditions and the number of traffic accidents in terms of three seasonal variations and a high probability of traffic accident occurrence under the above-mentioned conditions at the city entrances/exits, which represent vulnerable areas within the study area. Knowing the linear dependence and the spatial relation between the low light and the number of traffic accidents, as well as the consequences induced by their occurrence, enabled us to identify the areas of high traffic accident risk in Cluj-Napoca.

scholarly journals Morphological features of Hylotelephium triphillum (Haw.) Holub (Crassulaceae DC.) under different light conditions when introduced into the steppe zone

2016 ◽  
Vol 5 (2) ◽  
pp. 47-51
Author(s):  
Lidiya Vasilyevna Privalko
Keyword(s):  
Fruit Set ◽  
Steppe Zone ◽  
Botanical Garden ◽  
Light Conditions ◽  
Biometric Data ◽  
Habitat Features ◽  
Lighting Conditions ◽  
Air Temperatures ◽  
Natural Flora ◽  
The Impact

In recent decades floral devices in a natural style has been becoming more common in gardening. In this connection there was a need for the introduction and study of the natural flora of plants in order to attract them to simulate the decorative and resistant plants. The article presents the results of studies of the effect of different light conditions on the habitat features and decorative biomorphological Hylotelephium triphyllum (Haw.) Holub (Crassulaceae DC.) when introduced in SE Donetsk Botanical Garden. This species is found naturally in the flora of Donbass, a decorative, but, according to the results of our analysis, is rarely used in green construction. Bioecological certification of this type has been done. It has been determined that the impact of site lighting conditions on the growth and development of H. triphyllum expressed in significantly smaller numbers of vegetative and generative shoots in the shaded areas. However, since the diameter of the plants does not change, more thickened planting in these areas is not recommended. The author found the dependence of the variation of the biometric data on the lighting conditions. In the study of seasonal dynamics of H. triphyllum the author revealed that the development of above-ground organs of his passes with a positive amount of average daily air temperatures. The growing season lasts an average of 225 days. Start of spring regrowth is observed in the second half of March - early April, flowering - in August - September, fruits - in September - October. Vegetation stops when temperature goes below zero. Illumination of this type of habitat affect the time of vegetation beginning, budding, flowering, fruit set and fruit-bearing. On the shaded areas due to the later start of budding and flowering the most decorative period of H. triphyllum is shorter by an average of 10 days. This type is recommended for creation of group planting, stony hills, dry streams, rock gardens, rockeries, mixborders, curbs, ornamental compositions in the coastal zone of ornamental ponds and fountains in the steppe zone in areas with different light conditions, taking into account the above factors.

scholarly journals Space variability of hydrological responses of Nature-Based Solutions and the resulting uncertainty

2020 ◽  
Author(s):  
Yangzi Qiu ◽  
Igor da Silva Rocha Paz ◽  
Feihu Chen ◽  
Pierre-Antoine Versini ◽  
Daniel Schertzer ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Peak Flow ◽  
Hydrological Cycle ◽  
Green Roof ◽  
Spatial Arrangement ◽  
Intersection Theorem ◽  
Runoff Volume ◽  
Hydrological Responses ◽  
Total Runoff ◽  
The Impact

Abstract. During the last decades, the urban hydrological cycle has been strongly modified by the built environment, resulting in fast runoff and increasing the risk of waterlogging. Nature-Based Solutions (NBS), which apply green infrastructures, have been more and more widely considered as a sustainable approach for urban stormwater management. However, the assessment of NBS performance still requires further modelling development because of their hydrological responses sensitively depends on the representation of multiscale space variability of both the rainfall and the NBS distribution. Indeed, we initially argue this issue with the help of the multifractal intersection theorem. To illustrate the importance of this question, the spatial heterogeneous distributions of two series of NBS scenarios (porous pavement, rain garden, green roof, and combined) are quantified with the help of their fractal dimension. We point out consequences of their estimates. Then, a fully-distributed and physically-based hydrological model (Multi-Hydro) was applied to consider the studied catchment and these NBS scenarios with a spatial resolution of 10 m under two different types of rainfall: distributed and uniform, and for three rainfall events. These simulations show that the impact of spatial variability of rainfall on the uncertainty of peak flow of NBS scenarios ranges from about 8 % to 17 %, which is more pronounced than those of the total runoff volume. In addition, the spatial variability of the rainfall intensity at the largest rainfall peak responds almost linearly to the uncertainty of the peak flow of NBS scenarios. However, the hydrological responses of NBS scenarios are less affected by the spatial distribution of NBS. Finally, the intersection effects of the spatial variability of rainfall and the spatial arrangement of NBS seem more pronounced for the peak flow of green roof scenarios and the total runoff volume of combined scenarios.

scholarly journals Facilitating spatially-explicit assessments of ecosystem service delivery to support land use planning

One Ecosystem ◽  
2020 ◽  
Vol 5 ◽  
Author(s):  
Dirk Vrebos ◽  
Jan Staes ◽  
Steven Broekx ◽  
Leo de Nocker ◽  
Karen Gabriels ◽  
...  
Keyword(s):  
Decision Making ◽  
Land Use ◽  
Ecosystem Services ◽  
Ecosystem Service ◽  
Assessment Tools ◽  
Spatially Explicit ◽  
Practical Implementation ◽  
Time Investment ◽  
Wide Range ◽  
The Impact

Since the early 2000s, there have been substantial efforts to transform the concept of ecosystem services into practice. Spatial assessment tools are being developed to evaluate the impact of spatial planning on a wide range of ecosystem services. However, the actual implementation in decision-making remains limited. To improve implementation, tools that are tailored to local conditions can provide accurate, meaningful information. Instead of a generic and widely-applicable tool, we developed a regional, spatially-explicit tool (ECOPLAN-SE) to analyse the impact of changes in land use on the delivery of 18 ecosystem services in Flanders (Belgium). The tool incorporates ecosystem services relevant to policy-makers and managers and makes use of detailed local data and knowledge. By providing an easy-to-use tool, including the required spatial geodatasets, time investment and the learning curve remain limited for the user. With this tool, constraints to implement ecosystem service assessments in local decision-making are drastically reduced. We believe that region-specific decision support systems, like ECOPLAN-SE, are indispensable intermediates between the conceptual ecosystem service frameworks and the practical implementation in planning processes.

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