scholarly journals How slow breeding can be selected in seabirds: testing Lack's hypothesis

2006 ◽  
Vol 274 (1607) ◽  
pp. 275-279 ◽  
Author(s):  
F. Stephen Dobson ◽  
Pierre Jouventin
Keyword(s):  
Body Size ◽  
Strongly Correlated ◽  
Individual Selection ◽  
Ecological Constraints ◽  
Foraging Range ◽  
Reproductive Rates ◽  
The 1960S ◽  
David Lack

The historical debate of the 1960s between group and individual selection hinged on how the slow breeding of seabirds could be explained. While this debate was settled by the ascendance of individual selection, championed by David Lack, explanations for slow breeding in seabirds remain to be tested. We examined the slowest breeding of these birds, the albatrosses and petrels (order Procellariiformes), using analyses that statistically controlled for variations in body size and phylogeny. Incubation and fledging periods appeared strongly correlated, but this turned out to be largely explained by phylogeny. Nonetheless, developmental and reproductive rates were associated with the distance to the foraging range, as predicted under the hypothesis of ecological constraints on breeding pairs, and these results were independent of body size and phylogeny. Slower breeding in these seabirds appeared associated with the rigors of farther pelagic feeding, as Lack originally hypothesized.

Latitudinal body-mass trends in Oligo-Miocene mammals

Paleobiology ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 643-658
Author(s):  
John D. Orcutt ◽  
Samantha S. B. Hopkins
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Regional Scale ◽  
Latitudinal Gradients ◽  
Bergmann’S Rule ◽  
Strongly Correlated ◽  
Bergmann's Rule ◽  
Deep Time ◽  
Causal Factors ◽  
Primary Driver

AbstractPaleecological data allow not only the study of trends along deep-time chronological transects but can also be used to reconstruct ecological gradients through time, which can help identify causal factors that may be strongly correlated in modern ecosystems. We have applied such an analysis to Bergmann’s rule, which posits a causal relationship between temperature and body size in mammals. Bergmann’s rule predicts that latitudinal gradients should exist during any interval of time, with larger taxa toward the poles and smaller taxa toward the equator. It also predicts that the strength of these gradients should vary with time, becoming weaker during warmer periods and stronger during colder conditions. We tested these predictions by reconstructing body-mass trends within canid and equid genera at different intervals of the Oligo-Miocene along the West Coast of North America. To allow for comparisons with modern taxa, body mass was reconstructed along the same transect for modernCanisandOdocoileus. Of the 17 fossil genera analyzed, only two showed the expected positive relationship with latitude, nor was there consistent evidence for a relationship between paleotemperature and body mass. Likewise, the strength of body-size gradients does not change predictably with climate through time. The evidence for clear gradients is ambiguous even in the modern genera analyzed. These results suggest that, counter to Bergmann’s rule, temperature alone is not a primary driver of body size and underscore the importance of regional-scale paleoecological analyses in identifying such drivers.

scholarly journals Impact of Lake Morphology and Shallowing on the Rate of Overgrowth in Hard-Water Eutrophic Lakes

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1827 ◽  
Author(s):  
Agnieszka Lawniczak-Malińska ◽  
Mariusz Ptak ◽  
Sofia Celewicz ◽  
Adam Choiński
Keyword(s):  
Hard Water ◽  
Strongly Correlated ◽  
Eutrophic Lakes ◽  
Vegetation Growth ◽  
Lake Volume ◽  
Physico Chemical ◽  
Lake Morphology ◽  
West Part ◽  
The 1960S ◽  
Phytoplankton Blooming

Lake disappearance is one of the results of water eutrophication which leads to lake shallowing and overgrowth, and small and shallow lakes are the most threatened with degradation. We studied the effect of lake shallowing on its overgrowth, taking into account the morphometric parameters of water bodies. The study was performed in 20 lakes located in the central west part of Poland. The degree of lake shallowing was evaluated on the basis of bathymetric maps made in the 1960s and studies carried out presently. Additionally, an analysis of littoral coverage and macrophyte growth forms was investigated. Moreover, the composition, intensity of phytoplankton blooming, and physico-chemical parameters of the lake water were analyzed. Redundancy analysis shows that the lake volume, average depth, shallowing rate, and change in volume were the parameters that most strongly correlated with the share of macrophytes in the lakes. According to the regression analysis, the share of emergent macrophytes was significantly correlated with lake shallowing. No relation was found between phytoplankton blooming and lake shallowing. Conversely, the lakes with the highest rate of shallowing were characterized by the greatest share of vegetation, which suggested that vegetation growth had a significant impact on lake shallowing.

Morphometric variation in Clethrionomys gapperi: are all voles created equal?

1981 ◽  
Vol 59 (12) ◽  
pp. 2275-2283 ◽  
Author(s):  
Steve Mihok ◽  
William A. Fuller
Keyword(s):  
Body Size ◽  
Large Body ◽  
Population Cycles ◽  
Population Cycle ◽  
Clethrionomys Gapperi ◽  
Strongly Correlated ◽  
Morphometric Variation ◽  
Skull Size ◽  
Chitty Effect ◽  
Microtine Rodents

A general feature of population cycles in microtine rodents is the Chitty effect: large body size in peak populations. This phenomenon does not occur in a subarctic population of Clethrionomys gapperi that has been studied extensively for 15 years. Voles from various phases of the population cycle differ primarily in terms of complex patterns of "shape" rather than "size." These patterns are strongly correlated with environmental conditions during periods of growth or thermal stress. Increasing populations are nevertheless characterized by changes in the relationships between body size and skull size. Voles larger than predicted on the basis of their skull size are captured in springs characterized by an increase in density from the previous spring. Hence the Chitty effect is present in this population but it is expressed in a different way. Qualitative changes in some weakly cycling microtine populations may therefore be relatively difficult to detect without a better understanding of the mechanisms underlying this morphometric, behavioural, genetic complex.

A Quiet Revolution in State Lobbying: Government Growth and Interest Populations

2020 ◽  
pp. 106591292097549
Author(s):  
James M. Strickland
Keyword(s):  
Interest Groups ◽  
Political Mobilization ◽  
The Political ◽  
State Governments ◽  
Strongly Correlated ◽  
Quiet Revolution ◽  
Government Growth ◽  
Secondary Sources ◽  
Original Dataset ◽  
The 1960S

What explains contemporary numbers of interest groups in America? To answer this question and help address conflicting narratives in research, I examine the rise of interest groups in the states. Assembling an original dataset based on archival and secondary sources, I find that relatively few groups lobbied legislators prior to the 1960s or 1970s. During those decades, numbers of interest groups began to grow rapidly. I find that increases in lawmaking activities present inconsistent effects on the political mobilization of groups but increases in spending are strongly correlated with mobilization. In additional tests, I find that the effects of spending on group numbers vary by state and are not discernible in most states. In general, a historic transformation of state governments helps to account for the growth of state lobbying. Interest groups have remained active in state capitols ever since.

scholarly journals Combining sediment Cladocera remains and geochemistry to reveal the role of a large catchment in driving changes in a small subalpine lake (Lake Ledro, N-Italy)

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Manuela Milan ◽  
Richard Bindler ◽  
Monica Tolotti
Keyword(s):  
Body Size ◽  
Catchment Area ◽  
Ice Age ◽  
Lake Productivity ◽  
Cladocera Remains ◽  
Subalpine Lake ◽  
Catchment Areas ◽  
The 1960S ◽  
The Impact ◽  
Large Catchment

<p>Sediment Cladocera remains and geochemistry were analyzed at Lake Ledro, a small subalpine lake with a large catchment area located in northern Italy. The aim of the study was to investigate human, climate and hydrological impacts on the Cladocera community and on the geochemical components during the last few centuries. A sediment core was collected from the deepest point of Lake Ledro and radiometrically dated. Cladocera remains were analyzed to track the trophic lake evolution. The core bottom section revealed the dominance of Bosminidae in concomitance with nutrient pulses entering into the lake during major flood events. The abundance of species preferring cold water temperatures confirmed the deposition of this core section during the Little Ice Age. The flood event occurred in the first half of the 19<sup>th</sup> century produced a drastic increase in littoral species, due to the development of new habitats. The decrease in Cladocera densities during the following lake stage was followed by a rapid increase in planktonic species during the nutrient enrichment after the 1960s. Statistical analyses revealed a clear response of Cladocera community to climate variability during oligotrophic periods, while no relation to temperature changes was recorded during high nutrient levels. A preliminary study on Bosminidae and Daphnidae body size and appendages length was carried out to reconstruct major changes in the lake food web. Only <em>Bosminia</em> spp. revealed clear body size changes: minor shifts were recorded before the 1930s in relation to the low nutrient concentrations, while the major changes occurred during the 1980s were interpreted as related to the appearance of Cladocera invertebrate predators. Geochemical components were studied using X-ray fluorescence spectroscopy (XRF) analysis in order to recognize the impact of the large catchment area and from the lake-level regulations on the lake hydrology. Moreover the Si:Al ratios profile confirmed the increase in lake productivity after the 1960s. Although both Cladocera and geochemical analysis indicate major changes since the 1960s, they also revealed diverse responses to common external and local forcing, thus confirming the value of a multi-proxy approach for disentangling the lake responses to different environmental stressors. Moreover, it outlined the importance of larger catchment areas on small lakes as they are to a larger extent influenced by the modifications occurring in the drainage basin.</p>

The influence of body size and sex on the characteristics of harbour seal foraging trips

1998 ◽  
Vol 76 (6) ◽  
pp. 1044-1053 ◽  
Author(s):  
Paul M Thompson ◽  
Ann Mackay ◽  
Dominic J Tollit ◽  
Simon Enderby ◽  
Philip S Hammond
Keyword(s):  
Body Size ◽  
Activity Pattern ◽  
Diet Composition ◽  
Phoca Vitulina ◽  
Trip Duration ◽  
Energy Requirements ◽  
Endogenous Factors ◽  
Foraging Range ◽  
Harbour Seals ◽  
Size Population

Most pinnipeds disperse from centralised terrestrial sites to forage at sea, but the factors that result in variation inforaging-trip characteristics remain unclear. We investigated the influence of sex and body size on the summer foraging activityof radio-tagged harbour seals (Phoca vitulina) from Scotland. Mean foraging-trip duration (range 17–257 h) was stronglycorrelated with mean foraging range (range 4.3–55.0 km), but both were significantly shorter for females. The proportion oftime spent at sea, mean trip duration, and mean foraging range were all positively related to body size. Comparison with datafrom other study areas suggests that both environmental and endogenous factors shape foraging characteristics in this species.These sex and body size related differences in activity pattern and foraging range have important implications for themethodologies currently used to assess the population size, population energy requirements, and diet composition of coastalpinnipeds.

scholarly journals Fossil bivalves and the sclerochronological reawakening

Paleobiology ◽  
2021 ◽  
pp. 1-23
Author(s):  
David K. Moss ◽  
Linda C. Ivany ◽  
Douglas S. Jones
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Life Span ◽  
Evolutionary Ecology ◽  
Evolutionary Mechanisms ◽  
Growth Increments ◽  
Diversity Gradient ◽  
Extreme Longevity ◽  
The 1960S

Abstract The field of sclerochronology has long been known to paleobiologists. Yet, despite the central role of growth rate, age, and body size in questions related to macroevolution and evolutionary ecology, these types of studies and the data they produce have received only episodic attention from paleobiologists since the field's inception in the 1960s. It is time to reconsider their potential. Not only can sclerochronological data help to address long-standing questions in paleobiology, but they can also bring to light new questions that would otherwise have been impossible to address. For example, growth rate and life-span data, the very data afforded by chronological growth increments, are essential to answer questions related not only to heterochrony and hence evolutionary mechanisms, but also to body size and organism energetics across the Phanerozoic. While numerous fossil organisms have accretionary skeletons, bivalves offer perhaps one of the most tangible and intriguing pathways forward, because they exhibit clear, typically annual, growth increments and they include some of the longest-lived, non-colonial animals on the planet. In addition to their longevity, modern bivalves also show a latitudinal gradient of increasing life span and decreasing growth rate with latitude that might be related to the latitudinal diversity gradient. Is this a recently developed phenomenon or has it characterized much of the group's history? When and how did extreme longevity evolve in the Bivalvia? What insights can the growth increments of fossil bivalves provide about hypotheses for energetics through time? In spite of the relative ease with which the tools of sclerochronology can be applied to these questions, paleobiologists have been slow to adopt sclerochronological approaches. Here, we lay out an argument and the methods for a path forward in paleobiology that uses sclerochronology to answer some of our most pressing questions.

scholarly journals Energetic and ecological constraints on population density of reef fishes

2016 ◽  
Vol 283 (1823) ◽  
pp. 20152186 ◽  
Author(s):  
D. R. Barneche ◽  
M. Kulbicki ◽  
S. R. Floeter ◽  
A. M. Friedlander ◽  
A. P. Allen
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Population Density ◽  
Species Interactions ◽  
Spatial Scales ◽  
Small Body ◽  
Reef Fishes ◽  
Abundant Species ◽  
Global Scale ◽  
Ecological Constraints

Population ecology has classically focused on pairwise species interactions, hindering the description of general patterns and processes of population abundance at large spatial scales. Here we use the metabolic theory of ecology as a framework to formulate and test a model that yields predictions linking population density to the physiological constraints of body size and temperature on individual metabolism, and the ecological constraints of trophic structure and species richness on energy partitioning among species. Our model was tested by applying Bayesian quantile regression to a comprehensive reef-fish community database, from which we extracted density data for 5609 populations spread across 49 sites around the world. Our results indicate that population density declines markedly with increases in community species richness and that, after accounting for richness, energetic constraints are manifested most strongly for the most abundant species, which generally are of small body size and occupy lower trophic groups. Overall, our findings suggest that, at the global scale, factors associated with community species richness are the major drivers of variation in population density. Given that populations of species-rich tropical systems exhibit markedly lower maximum densities, they may be particularly susceptible to stochastic extinction.

scholarly journals A Continuum Approach to Understanding Changes in the ENSO-Indian Monsoon Relationship

2020 ◽  
pp. 1-49
Author(s):  
Justin Schulte ◽  
Fredrick Policielli ◽  
Benjamin Zaitchik
Keyword(s):  
Southern Oscillation ◽  
Monsoon Season ◽  
Rainfall Variability ◽  
Strongly Correlated ◽  
Sea Surface Temperature Anomalies ◽  
Indian Rainfall ◽  
The 1960S ◽  
June July ◽  
Work Supports ◽  
The Relationship

AbstractIt is well-documented that the relationship between the El Niño/Southern Oscillation (ENSO) and the Indian summer monsoon changes on interdecadal timescales, yet an explanation for the variations is still a subject of debate. Here, using a continuum framework based on one-point partial correlation maps, we show that the ENSO-Indian rainfall relationship is influenced by the gradient of sea surface temperature anomalies (SSTA) across the Niño 3 region. Based on this identified SSTA pattern, a simple trans Niño 3 (TN3) index is created that explains up to 50% of All-India rainfall variability during the mid to late monsoon season after the 1960s. It is also shown that the influence of the TN3 pattern on the relationship between common ENSO metrics and All-India rainfall is strongest during the August-September (AS) monsoon sub-season and weakest during the June-July sub-season. The TN3 pattern accounts for up to 80% of the change and sign reversal in the AS Niño 1+2-All-India rainfall relationship in recent decades. The 1940s coincides with the intensification of the TN3 pattern and its influence. As the TN3 index is nearly orthogonal to the Niño 3 index, and both are strongly correlated with All-India rainfall, the strengthening TN3 influence must be systematically associated with the weakening Niño 3-All-India relationship in recent decades. This work supports arguments that recent changes in the ENSO-Indian rainfall relationship are not solely related to noise.

scholarly journals Biodiversity and body size are linked across metazoans

2009 ◽  
Vol 276 (1665) ◽  
pp. 2209-2215 ◽  
Author(s):  
Craig R. McClain ◽  
Alison G. Boyer
Keyword(s):  
Body Size ◽  
Species Diversity ◽  
Strong Correlation ◽  
Size Variation ◽  
Maximum Size ◽  
Minimum Size ◽  
Biological Processes ◽  
Strongly Correlated ◽  
Body Size Variation ◽  
Body Sizes

Body size variation across the Metazoa is immense, encompassing 17 orders of magnitude in biovolume. Factors driving this extreme diversification in size and the consequences of size variation for biological processes remain poorly resolved. Species diversity is invoked as both a predictor and a result of size variation, and theory predicts a strong correlation between the two. However, evidence has been presented both supporting and contradicting such a relationship. Here, we use a new comprehensive dataset for maximum and minimum body sizes across all metazoan phyla to show that species diversity is strongly correlated with minimum size, maximum size and consequently intra-phylum variation. Similar patterns are also observed within birds and mammals. The observations point to several fundamental linkages between species diversification and body size variation through the evolution of animal life.

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