scholarly journals Diverging life cycle patterns of two Diamesa species (Diptera, Chironomidae) in High Arctic streams, Svalbard

Polar Biology ◽  
2021 ◽  
Author(s):  
Stefan Andreas Schütz ◽  
John E. Brittain ◽  
Leopold Füreder
Keyword(s):  
Life Histories ◽  
Spatial Scales ◽  
Larval Growth ◽  
Water Source ◽  
Food Concentration ◽  
High Arctic ◽  
Physiological Limits ◽  
Ecological Importance ◽  
Arctic Streams ◽  
Life Cycle Patterns

AbstractThe fauna of streams in the High Arctic, dominated by chironomids, is shaped by extreme environmental conditions that represent the physiological limits for benthic invertebrates. Despite their ecological importance, little is known of chironomid life histories, development strategies and the key abiotic drivers limiting larval growth in High Arctic streams. We investigated the larval development and growth in three High Arctic rivers with contrasting water sources, thermal regimes and nutrient characteristics. Populations of the larvae of Diamesa bohemani (Goetghebuer 1932) and Diamesa aberrata (Lundbeck 1898) from two sampling occasions in July and August 2016 were morphometrically analysed to determine life history patterns and instream productivity. Water temperature differences lead to diverging development patterns on local spatial scales. The lowest larval growth was in a groundwater/snowmelt fed stream with low food concentration and quality, suggesting that stream productivity is not primarily water source dependant, but is dependent on the nutrient supply. Glacially influenced streams are clearly more productive than previously assumed, resulting in comparable secondary production to groundwater/snowmelt-fed streams.

scholarly journals Highly restricted dispersal in habitat-forming seaweed may impede natural recovery of disturbed populations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Florentine Riquet ◽  
Christiane-Arnilda De Kuyper ◽  
Cécile Fauvelot ◽  
Laura Airoldi ◽  
Serge Planes ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Spatial Scales ◽  
Mediterranean Ecosystems ◽  
Dispersal Distance ◽  
Genetic Connectivity ◽  
Restricted Gene Flow ◽  
Isolated Populations ◽  
Natural Recovery ◽  
Limited Dispersal ◽  
Ecological Importance

AbstractCystoseira sensu lato (Class Phaeophyceae, Order Fucales, Family Sargassaceae) forests play a central role in marine Mediterranean ecosystems. Over the last decades, Cystoseira s.l. suffered from a severe loss as a result of multiple anthropogenic stressors. In particular, Gongolaria barbata has faced multiple human-induced threats, and, despite its ecological importance in structuring rocky communities and hosting a large number of species, the natural recovery of G. barbata depleted populations is uncertain. Here, we used nine microsatellite loci specifically developed for G. barbata to assess the genetic diversity of this species and its genetic connectivity among fifteen sites located in the Ionian, the Adriatic and the Black Seas. In line with strong and significant heterozygosity deficiencies across loci, likely explained by Wahlund effect, high genetic structure was observed among the three seas (ENA corrected FST = 0.355, IC = [0.283, 0.440]), with an estimated dispersal distance per generation smaller than 600 m, both in the Adriatic and Black Sea. This strong genetic structure likely results from restricted gene flow driven by geographic distances and limited dispersal abilities, along with genetic drift within isolated populations. The presence of genetically disconnected populations at small spatial scales (< 10 km) has important implications for the identification of relevant conservation and management measures for G. barbata: each population should be considered as separated evolutionary units with dedicated conservation efforts.

Multi-level social-ecological networks in a payments for ecosystem services programme in central Veracruz, Mexico

2020 ◽  
pp. 1-7
Author(s):  
Alfonso Langle-Flores ◽  
Adriana Aguilar Rodríguez ◽  
Humberto Romero-Uribe ◽  
Julia Ros-Cuéllar ◽  
Juan José Von Thaden
Keyword(s):  
Ecosystem Services ◽  
Spatial Scales ◽  
Payments For Ecosystem Services ◽  
Collaboration Network ◽  
Governmental Organizations ◽  
Social Ecological ◽  
Non Governmental Organizations ◽  
Conservation Activity ◽  
Ecological Importance ◽  
Hydrological Services

Summary Payments for ecosystem services (PES) programmes have been considered an important conservation mechanism to avoid deforestation. These environmental policies act in social and ecological contexts at different spatial scales. We evaluated the social-ecological fit between stakeholders and ecosystem processes in a local PES programme across three levels: social, ecological and social-ecological. We explored collaboration among stakeholders, assessed connectivity between forest units and evaluated conservation activity links between stakeholders and forest units. In addition, to increase programme effectiveness, we classified forest units based on their social and ecological importance. Our main findings suggest that non-governmental organizations occupy brokerage positions between landowners and government in a dense collaboration network. We also found a partial spatial misfit between conservation activity links and the forest units that provide the most hydrological services to Xalapa. We conclude that conservation efforts should be directed towards the middle and high part of the Pixquiac sub-watershed and that the role of non-governmental organizations as mediators should be strengthened to increase the efficiency and effectiveness of the local PES programme.

scholarly journals Archaeal ammonia oxidizers respond to soil factors at smaller spatial scales than the overall archaeal community does in a high Arctic polar oasis

2016 ◽  
Vol 62 (6) ◽  
pp. 485-491 ◽  
Author(s):  
Samiran Banerjee ◽  
Nabla Kennedy ◽  
Alan E. Richardson ◽  
Keith N. Egger ◽  
Steven D. Siciliano
Keyword(s):  
Community Structure ◽  
Spatial Scales ◽  
Archaeal Community ◽  
Diversity Indices ◽  
High Arctic ◽  
Total Carbon ◽  
Spatial Dependency ◽  
Edaphic Factors ◽  
Total Carbon Content ◽  
Arctic Soils

Archaea are ubiquitous and highly abundant in Arctic soils. Because of their oligotrophic nature, archaea play an important role in biogeochemical processes in nutrient-limited Arctic soils. With the existing knowledge of high archaeal abundance and functional potential in Arctic soils, this study employed terminal restriction fragment length polymorphism (t-RFLP) profiling and geostatistical analysis to explore spatial dependency and edaphic determinants of the overall archaeal (ARC) and ammonia-oxidizing archaeal (AOA) communities in a high Arctic polar oasis soil. ARC communities were spatially dependent at the 2–5 m scale (P < 0.05), whereas AOA communities were dependent at the ∼1 m scale (P < 0.0001). Soil moisture, pH, and total carbon content were key edaphic factors driving both the ARC and AOA community structure. However, AOA evenness had simultaneous correlations with dissolved organic nitrogen and mineral nitrogen, indicating a possible niche differentiation for AOA in which dry mineral and wet organic soil microsites support different AOA genotypes. Richness, evenness, and diversity indices of both ARC and AOA communities showed high spatial dependency along the landscape and resembled scaling of edaphic factors. The spatial link between archaeal community structure and soil resources found in this study has implications for predictive understanding of archaea-driven processes in polar oases.

Small-scale temporal and spatial variation in Atlantic cod (Gadus morhua) life history

2003 ◽  
Vol 60 (9) ◽  
pp. 1111-1121 ◽  
Author(s):  
Tara M McIntyre ◽  
Jeffrey A Hutchings
Keyword(s):  
Body Mass ◽  
Life Histories ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Spatial Scales ◽  
Gonadosomatic Index ◽  
Small Scale ◽  
Hepatosomatic Index ◽  
Georges Bank ◽  
High Fecundity

Life histories of Atlantic cod (Gadus morhua) from the Gulf of St. Lawrence south to Georges Bank differ significantly through time and space. Within the Southern Gulf, fecundity per unit body mass differed by more than 40% over short (2 years) and long (42–45 years) periods of time. Significant variation in size-specific fecundity is also evident among populations: Southern Gulf cod produce almost 30% more eggs per unit body mass than those on Georges Bank, whereas fecundity of Scotian Shelf cod is almost half that of cod in Sydney Bight. Compared with those on Georges Bank, Southern Gulf cod life histories are characterized by high fecundity, late maturity, high gonadosomatic index, and large eggs. Relative to the influence of body size, neither temporal nor spatial differences in fecundity can be attributed to physiological condition, as reflected by liver weight, hepatosomatic index, and Fulton's K. Delayed maturity and higher reproductive allotment among Southern Gulf cod can be explained as selection responses to slower growth, higher prereproductive mortality, and fewer lifetime reproductive events. Patterns of covariation in heritable, fitness-related traits suggest the existence of adaptive variation and evolutionarily significant units at spatial scales considerably smaller than the species range in the Northwest Atlantic.

Community Ecology of Stream Fishes: Concepts, Approaches, and Techniques

2010 ◽  
Keyword(s):  
Great Plains ◽  
Life Histories ◽  
Environmental Heterogeneity ◽  
Environmental Variability ◽  
Spatial Scales ◽  
Stream Fish ◽  
Metapopulation Dynamics ◽  
Stream Fishes ◽  
Spatial And Temporal Scales ◽  
Trade Offs

<em>Abstract</em>.—Stream fishes carry out their life histories across broad spatial and temporal scales, leading to spatially structured populations. Therefore, incorporating metapopulation dynamics into models of stream fish populations may improve our ability to understand mechanisms regulating them. First, we reviewed empirical research on metapopulation dynamics in the stream fish ecology literature and found 31 papers that used the metapopulation framework. The majority of papers applied no specific metapopulation model, or included space only implicitly. Although parameterization of spatially realistic models is challenging, we suggest that stream fish ecologists should incorporate space into models and recognize that metapopulation types may change across scales. Second, we considered metacommunity theory, which addresses how trade-offs among dispersal, environmental heterogeneity, and biotic interactions structure communities across spatial scales. There are no explicit tests of metacommunity theory using stream fishes to date, so we used data from our research in a Great Plains stream to test the utility of these paradigms. We found that this plains fish metacommunity was structured mainly by spatial factors related to dispersal opportunity and, to a lesser extent, by environmental heterogeneity. Currently, metacommunity models are more heuristic than predictive. Therefore, we propose that future stream fish metacommunity research should focus on developing testable hypotheses that incorporate stream fish life history attributes, and seasonal environmental variability, across spatial scales. This emerging body of research is likely to be valuable not only for basic stream fish ecological research, but also multispecies conservation and management.

Life histories, ecological tolerance limits, and the evolution of geographic range size in Eucalyptus (Myrtaceae)

2005 ◽  
Vol 53 (6) ◽  
pp. 501 ◽  
Author(s):  
Sally Mathews ◽  
Stephen P. Bonser
Keyword(s):  
Life History ◽  
Drought Tolerance ◽  
Life Histories ◽  
Spatial Scales ◽  
Geographic Range ◽  
Range Size ◽  
Tolerance Limits ◽  
Physiological Tolerance ◽  
Australian Continent ◽  
The Impact

Current theories explaining variability in species geographic range sizes in plants tend to focus on how traits associated with either physiological tolerance limits or life histories are related to range size. In trees, aspects of both physiological tolerance (e.g. drought tolerance) and life history (e.g. life span and growth rate) are related to stem traits such as wood density and height relative to diameter. We examined how the evolution of stem traits is related to geographic range sizes in Eucalyptus at two spatial scales: across the Australian continent and within the wet forests near the east coast of Australia. Geographic range sizes were estimated from herbarium records. Stem trait data were collected from both natural populations and published sources. We used phylogenetically independent contrasts to test for evolutionary associations between stem traits and geographic range sizes. Across Australia, the evolution of stem traits conferring drought tolerance were not consistently associated greater range sizes. This was surprising since arid and semi-arid environments are geographically expansive. Within the eastern forests, the evolution of stem traits defining slow growing, competitively dominant life histories were associated with greater range sizes. These stem traits should confer both a capacity to disperse into previously unoccupied habitats and the ability to persist in habitats already occupied. Traits associated with physiological tolerance and life history had significant effects on the evolution of range sizes in Eucalyptus. However, we demonstrate that the impact of these traits on range size evolution depends on both environmental conditions and the scale at which these traits are examined.

scholarly journals From an irrigation system to an ecological asset: adding environmental flows establishes recovery of a threatened fish species

2019 ◽  
Vol 70 (9) ◽  
pp. 1295 ◽  
Author(s):  
Ivor Stuart ◽  
Clayton Sharpe ◽  
Kathryn Stanislawski ◽  
Anna Parker ◽  
Martin Mallen-Cooper
Keyword(s):  
Water Level ◽  
Fish Species ◽  
Life Histories ◽  
Environmental Flows ◽  
Irrigation System ◽  
Spatial Scales ◽  
Environmental Water ◽  
Environmental Flow ◽  
Murray Cod ◽  
Riverine Fish

Worldwide, riverine fish are the target of environmental water because populations have declined in lotic river habitats following river regulation. Murray cod is an endangered Australian riverine fish with remaining populations associated with lotic river reaches with instream habitat, including some creeks operated as part of irrigation systems. Our objectives were to develop a life history model, apply the building block method of environmental flows to enhance the abundance of juvenile Murray cod and promote population recovery. From 2008 to 2018 we evaluated changes to Murray cod juvenile abundance before and after implementation of a perennial environmental flow regime that began in 2013. During the first year of the environmental flow, larvae were collected as evidence of spawning. Murray cod abundance can be enhanced with environmental flows that target: (1) an annual spring spawning or recruitment flow with no rapid water level drops; (2) maximising hydrodynamic complexity (i.e. flowing habitats that are longitudinally continuous and hydrodynamically complex); and (3) an annual base winter connection flow. Recognition that incorporating hydraulics (water level and velocity) at fine and coarse time scales, over spatial scales that reflect life histories, provides broader opportunities to expand the scope of environmental flows to help restore imperilled fish species in regulated ecosystems.

scholarly journals A modelling study of the influence of environment and food supply on survival of Crassostrea gigas larvae

2004 ◽  
Vol 61 (4) ◽  
pp. 596-616 ◽  
Author(s):  
Eileen E Hofmann ◽  
Eric N Powell ◽  
Eleanor A Bochenek ◽  
John M Klinck
Keyword(s):  
Genetic Variation ◽  
Food Quality ◽  
Egg Quality ◽  
Larval Growth ◽  
High Growth ◽  
Growth Efficiency ◽  
Food Concentration ◽  
Larval Survival ◽  
Food Concentrations ◽  
Food Content

Abstract A biochemically based model was developed to simulate the growth, development, and metamorphosis of larvae of the Pacific oyster (Crassostrea gigas). The unique characteristics of the model are that it: (1) defines larvae in terms of their protein, neutral lipid, polar lipid, carbohydrate, and ash content; (2) tracks weight separately from length to follow larval condition; and (3) includes genetic variation in growth efficiency and egg quality to better simulate cohort population dynamics. The model includes parameterizations for filtration, ingestion, and respiration, which determine larval growth rate, and processes controlling larval mortality and metamorphosis. Changes in larval tissue composition occur as the larva grows and in response to the biochemical composition of the food. Simulations of larval growth indicate that departures of temperature, salinity, or food content from optimum levels reduce larval cohort survival, either because of metabolic constraints that result in death, unsuccessful metamorphosis, or increased predation resulting from increased larval lifespan. Temperatures and salinities near optimal values improve larval survival at low food concentration by increasing ingestion rate or growth efficiency. Also, survival at a given food concentration can vary widely depending on food composition, which determines food quality. The simulations suggest that the ratio of carbohydrate + lipid-to-protein may best describe the overall food quality, with optimal food compositions being characterized by ratios near 1.2 to 1.4 over a range of food concentrations. In contrast, food compositions containing too much or too little protein reduce larval survival, even at saturating food concentrations. In simulations emphasizing genetic variability within the cohort, larvae with high growth efficiency originating from large eggs out-perform other egg quality–growth efficiency combinations over a wide range of temperature, salinity, and food contents. As a consequence, suboptimal temperature, salinity, or food content compresses genetic variation by uniformly favouring larvae from large eggs with a high growth efficiency. However, the larval survival obtained from simulations that use a range of food qualities is representative of a much broader range of genetic types. Thus, the simulations support the supposition that food quality is an important variable controlling the survival and genetic variability of C. gigas larval cohorts.

Issues Based on Species Life History and Behavior

2021 ◽  
pp. 89-94
Author(s):  
Joseph A. Veech
Keyword(s):  
Life History ◽  
Habitat Use ◽  
Life Histories ◽  
Radio Telemetry ◽  
Spatial Scales ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Habitat Analysis ◽  
The Individual ◽  
And Behavior

Species vary tremendously in their life histories and behavior. The particular life history traits and behavior of the focal species must be considered when designing a study to examine habitat associations. For some species, individuals use different areas (of the landscape or territory) for breeding and foraging. As such, the important characteristics for the foraging and breeding habitats may be different. The dramatically different life stages of some organisms (e.g., amphibians and some insects) often correspond to equally dramatic differences in habitat use between juveniles and adults. For some species, habitat use differs among seasons. Species that are highly mobile and have individuals that move around substantially on a daily or weekly basis are particularly challenging for a habitat analysis. For these species, the most efficient and appropriate study design may be one that tracks individuals (through radio-telemetry or GPS) and analyzes the environmental or habitat characteristics at locations where the individual has stopped, rather than trying to survey for the species in pre-established and insufficiently small survey plots. In addition, individual movement and the issues mentioned above may necessitate that environmental variables are measured and analyzed at multiple spatial scales.

The life histories of Limnephilus externus Hagen, Anabolia bimaculata (Walker), and Nemotaulius hostilis (Hagen) (Trichoptera, Limnephilidae) in a pond in southern Alberta, Canada

1986 ◽  
Vol 64 (10) ◽  
pp. 2348-2356 ◽  
Author(s):  
Stephen B. Berté ◽  
Gordon Pritchard
Keyword(s):  
Water Level ◽  
Life Histories ◽  
Larval Growth ◽  
Metabolic Cost ◽  
Late Summer ◽  
Adult Emergence ◽  
High Water ◽  
Reproductive Diapause ◽  
Fluctuating Water Level ◽  
The Masses

Limnephilus externus and Anabolia bimaculata are caddisflies that typically inhabit temporary pools, while Nemotaulius hostilis is a species that inhabits permanent pools. In a permanent pond with a fluctuating water level, both groups could be accommodated. The temporary-pool species laid egg masses on the ground above the water level in late summer. Larvae hatched in the autumn but remained in the masses until submersed by the rising water in the spring. Larvae grew at rates faster than those for any permanent-water trichopteran studied to date. Limnephilus externus adults emerged through August and underwent a 1-month reproductive delay. Anabolia bimaculata adults emerged through July, but showed no signs of a reproductive delay. By contrast, N. hostilis oviposited on riparian vegetation and larvae entered the water on hatching in August. Larval growth rates approximated those of other detritivorous shredders found in permanent waters. Over 75% of adult emergence occurred in 1 week at the end of May and adults underwent a reproductive diapause of slightly over a month's duration. The metabolic cost of high water temperatures on cool-adapted limnephilid caddisflies is postulated as the driving force behind the evolution of reproductive diapause in this family.

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