A HEMISPHERIC ASSESSMENT OF SCALE DEPENDENCE IN LATITUDINAL GRADIENTS OF SPECIES RICHNESS

Ecology ◽  
1999 ◽  
Vol 80 (8) ◽  
pp. 2483-2491 ◽  
Author(s):  
S. Kathleen Lyons ◽  
Michael R. Willig
Keyword(s):  
Species Richness ◽  
Scale Dependence ◽  
Latitudinal Gradients

scholarly journals Using Biogeography to Assess Key Adaptation Strength in Two Bird Families

2017 ◽  
Author(s):  
Abdel H. Halloway ◽  
Christopher J. Whelan ◽  
Çağan H. Şekercioğlu ◽  
Joel S. Brown
Keyword(s):  
Species Richness ◽  
Environmental Conditions ◽  
New World ◽  
Extreme Environments ◽  
The Other ◽  
Latitudinal Gradients ◽  
Old World ◽  
Extended Range

AbstractAdaptations can be thought of as evolutionary technologies which allow an organism to exploit environments. Among convergent taxa, adaptations may be largely equivalent with the taxa operating in a similar set of environmental conditions, divergent with the taxa operating in different sets of environmental conditions, or superior with one taxon operating within an extended range of environmental conditions than the other. With this framework in mind, we sought to characterize the adaptations of two convergent nectarivorous bird families, the New World hummingbirds (Trochilidae) and Old World sunbirds (Nectariniidae), by comparing their biogeography. Looking at their elevational and latitudinal gradients, hummingbirds not only extend into but also maintain species richness in more extreme environments. We suspect that hummingbirds have a superior key adaptation that sunbirds lack, namely a musculoskeletal architecture that allows for hovering. Through biogeographic comparisons, we have been able to assess and understand adaptations as evolutionary technologies among two convergent bird families, a process that should work for most taxa.

scholarly journals Latitudinal gradients in biotic niche breadth vary across ecosystem types

2015 ◽  
Vol 282 (1819) ◽  
pp. 20151589 ◽  
Author(s):  
Alyssa R. Cirtwill ◽  
Daniel B. Stouffer ◽  
Tamara N. Romanuk
Keyword(s):  
Species Richness ◽  
Food Webs ◽  
Niche Breadth ◽  
The Other ◽  
Latitudinal Gradients ◽  
Food Web Structure ◽  
Scaling Relationships ◽  
Web Structure ◽  
Scaling Relationship ◽  
The Tropics

Several properties of food webs—the networks of feeding links between species—are known to vary systematically with the species richness of the underlying community. Under the ‘latitude–niche breadth hypothesis’, which predicts that species in the tropics will tend to evolve narrower niches, one might expect that these scaling relationships could also be affected by latitude. To test this hypothesis, we analysed the scaling relationships between species richness and average generality, vulnerability and links per species across a set of 196 empirical food webs. In estuarine, marine and terrestrial food webs there was no effect of latitude on any scaling relationship, suggesting constant niche breadth in these habitats. In freshwater communities, on the other hand, there were strong effects of latitude on scaling relationships, supporting the latitude–niche breadth hypothesis. These contrasting findings indicate that it may be more important to account for habitat than latitude when exploring gradients in food-web structure.

Metabolic asymmetry and the global diversity of marine predators

Science ◽  
2019 ◽  
Vol 363 (6425) ◽  
pp. eaat4220 ◽  
Author(s):  
John M. Grady ◽  
Brian S. Maitner ◽  
Ara S. Winter ◽  
Kristin Kaschner ◽  
Derek P. Tittensor ◽  
...  
Keyword(s):  
Species Richness ◽  
Spatial Patterns ◽  
Marine Mammals ◽  
Phylogenetic Diversity ◽  
Latitudinal Gradient ◽  
Latitudinal Gradients ◽  
Competitive Interactions ◽  
Marine Predators ◽  
Theoretical Predictions ◽  
The Tropics

Species richness of marine mammals and birds is highest in cold, temperate seas—a conspicuous exception to the general latitudinal gradient of decreasing diversity from the tropics to the poles. We compiled a comprehensive dataset for 998 species of sharks, fish, reptiles, mammals, and birds to identify and quantify inverse latitudinal gradients in diversity, and derived a theory to explain these patterns. We found that richness, phylogenetic diversity, and abundance of marine predators diverge systematically with thermoregulatory strategy and water temperature, reflecting metabolic differences between endotherms and ectotherms that drive trophic and competitive interactions. Spatial patterns of foraging support theoretical predictions, with total prey consumption by mammals increasing by a factor of 80 from the equator to the poles after controlling for productivity.

scholarly journals Latitudinal gradients in body size in marine tardigrades

2019 ◽  
Vol 188 (3) ◽  
pp. 820-838
Author(s):  
Paul J Bartels ◽  
Diego Fontaneto ◽  
Milena Roszkowska ◽  
Diane R Nelson ◽  
Łukasz Kaczmarek
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Net Primary Productivity ◽  
Linear Models ◽  
Generalized Least Squares ◽  
Sampling Bias ◽  
Latitudinal Gradients ◽  
Biased Sampling ◽  
Sampling Effort ◽  
Latitudinal Pattern

Abstract Homeotherms and many poikilotherms display a positive relationship between body size and latitude, but this has rarely been investigated in microscopic animals. We analysed all published records of marine Tardigrada to address whether microscopic marine invertebrates have similar ecogeographical patterns to macroscopic animals. The data were analysed using spatially explicit generalized least squares models and linear models. We looked for latitudinal patterns in body size and species richness, testing for sampling bias and phylogenetic constraints. No latitudinal pattern was detected for species richness, and sampling bias was the strongest correlate of species richness. A hump-shaped increase in median body size with latitude was found, and the effect remained significant for the Northern Hemisphere but not for the Southern. The most significant effect supporting the latitudinal gradient was on minimum body size, with smaller species disappearing at higher latitudes. Our results suggest that biogeographical signals were observed for body size, albeit difficult to detect in poorly studied groups because of swamping from biased sampling effort and from low sample size. We did not find a significant correlation with the latitudinal pattern of body size and ecologically relevant net primary productivity.

scholarly journals Temporal species turnover and plant community changes across different habitats in the Lake Engure Nature Park, Latvia

2014 ◽  
Vol 68 (1-2) ◽  
pp. 68-79 ◽  
Author(s):  
Solvita Rūsiņa ◽  
Ģertrūde Gavrilova ◽  
Ieva Roze ◽  
Viesturs Šulcs
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Vegetation Dynamics ◽  
Species Turnover ◽  
Dry Forest ◽  
Latitudinal Gradients ◽  
Nature Park ◽  
The Stability ◽  
Window Approach ◽  
Temporal Species Turnover

Abstract Simultaneous monitoring of vegetation dynamics in different ecosystems has been rarely conducted but can provide important insights into mechanisms of vegetation dynamics in relation to vegetation structure and patterns. We compared the herb layer dynamics, species turnover, and species-time relationships across different habitats in a 12-year period in the ILTER monitoring station of the Lake Engure Nature Park, Latvia. Temporal species turnover was defined as diference in species composition in a community between two times. Species-time relationships were assessed using a sliding window approach. Species richness, cumulative species richness, and diversity changed more in species-rich non-forest habitats than in forests. Species turnover was highly different among habitats, and was not associated with the stability of habitats, as reported from other studies. The species-time relationship of six habitats was much lower than that reported in the literature. This could be explained by latitudinal gradients in species diversity and temporal turnover. At higher latitudes both species diversity and turnover is lower, and the mentioned habitats represent typical boreal vegetation. Vegetation dynamics in acidic grassland, dune slack, fen, and dune forest were interpreted as fluctuations. Vegetation changes in moist forest, dry forest, and coastal grassland showed clear signs of succession (xerophytisation and overgrowing). Vegetation dynamics of the beach community exhibited features of both natural succession and anthropogenic fluctuation.

Scale dependence of plant species richness in a network of protected areas

2011 ◽  
Vol 21 (2) ◽  
pp. 503-516 ◽  
Author(s):  
A. Chiarucci ◽  
G. Bacaro ◽  
G. Filibeck ◽  
S. Landi ◽  
S. Maccherini ◽  
...  
Keyword(s):  
Species Richness ◽  
Protected Areas ◽  
Plant Species ◽  
Plant Species Richness ◽  
Scale Dependence
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