The Latitudinal Gradient in Geographical Range: How so Many Species Coexist in the Tropics

1989 ◽  
Vol 133 (2) ◽  
pp. 240-256 ◽  
Author(s):  
George C. Stevens
Keyword(s):  
Latitudinal Gradient ◽  
Geographical Range ◽  
The Tropics

Latitudinal gradient of termite diversity indicates higher diversification and narrower thermal niches in the tropics

2020 ◽  
Vol 29 (11) ◽  
pp. 1967-1977
Author(s):  
Felipe Osmari Cerezer ◽  
Renato Almeida Azevedo ◽  
Marcelo André Souza Nascimento ◽  
Elizabeth Franklin ◽  
José Wellington Morais ◽  
...  
Keyword(s):  
Latitudinal Gradient ◽  
The Tropics

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.

Does a latitudinal gradient in seedling survival favour larger seeds in the tropics?

2004 ◽  
Vol 7 (10) ◽  
pp. 911-914 ◽  
Author(s):  
Angela T. Moles ◽  
David I. Warton ◽  
Richard D. Stevens ◽  
Mark Westoby
Keyword(s):  
Latitudinal Gradient ◽  
Seedling Survival ◽  
The Tropics

scholarly journals Phylogenetic support for the Tropical Niche Conservatism Hypothesis despite the absence of a clear latitudinal species richness gradient in Yunnan's woody flora

2014 ◽  
Vol 11 (5) ◽  
pp. 7055-7077 ◽  
Author(s):  
G. Tang ◽  
M. G. Zhang ◽  
C. Liu ◽  
Z. Zhou ◽  
W. Chen ◽  
...  
Keyword(s):  
Species Richness ◽  
Phylogenetic Diversity ◽  
Latitudinal Gradient ◽  
Extreme Temperature ◽  
Woody Species ◽  
Niche Conservatism ◽  
The North ◽  
Related Plant ◽  
Species Richness Gradient ◽  
The Tropics

Abstract. The Tropical Niche Conservatism Hypothesis (TCH) tries to explain the generally observed latitudinal gradient of increasing species diversity towards the tropics. To date, few studies have used phylogenetic approaches to assess its validity, even though such methods are especially suited to detect changes in niche structure. We test the TCH using modeled distributions of 1898 woody species in Yunnan Province (southwest China) in combination with a family level phylogeny. Unlike predicted, species richness and phylogenetic diversity did not show a latitudinal gradient, but identified two high diversity zones, one in Northwest and one in South Yunnan. Despite this, the underlying residual phylogenetic diversity showed a clear decline away from the tropics, while the species composition became progressingly more phylogenetically clustered towards the North. These latitudinal changes were strongly associated with more extreme temperature variability and declining precipitation and soil water availability, especially during the dry season. Our results suggests that the climatically more extreme conditions outside the tropics require adaptations for successful colonization, most likely related to the plant hydraulic system, that have been acquired by only a limited number of phylogenetically closely related plant lineages. We emphasize the importance of phylogenetic approaches for testing the TCH.

scholarly journals Character displacement drives trait divergence in a continental fauna

2021 ◽  
Vol 118 (20) ◽  
pp. e2021209118
Author(s):  
Sean A. S. Anderson ◽  
Jason T. Weir
Keyword(s):  
Evolutionary Theory ◽  
Species Interactions ◽  
New World ◽  
Latitudinal Gradient ◽  
Character Displacement ◽  
Sympatric Species ◽  
Closely Related Species ◽  
Species Sorting ◽  
Trait Divergence ◽  
The Tropics

Coexisting (sympatric) pairs of closely related species are often characterized by exaggerated trait differences. This widespread pattern is consistent with adaptation for reduced similarity due to costly interactions (i.e., “character displacement”)—a classic hypothesis in evolutionary theory. But it is equally consistent with a community assembly bias in which lineages with greater trait differences are more likely to establish overlapping ranges in the first place (i.e., “species sorting”), as well as with null expectations of trait divergence through time. Few comparative analyses have explicitly modeled these alternatives, and it remains unclear whether trait divergence is a general prerequisite for sympatry or a consequence of interactions between sympatric species. Here, we develop statistical models that allow us to distinguish the signature of these processes based on patterns of trait divergence in closely related lineage pairs. We compare support for each model using a dataset of bill shape differences in 207 pairs of New World terrestrial birds representing 30 avian families. We find that character displacement models are overwhelmingly supported over species sorting and null expectations, indicating that exaggerated bill shape differences in sympatric pairs result from enhanced divergent selection in sympatry. We additionally detect a latitudinal gradient in character displacement, which appears strongest in the tropics. Our analysis implicates costly species interactions as powerful drivers of trait divergence in a major vertebrate fauna. These results help substantiate a long-standing but equivocally supported linchpin of evolutionary theory.

scholarly journals A latitudinal gradient in rates of evolution of avian syllable diversity and song length

2010 ◽  
Vol 278 (1712) ◽  
pp. 1713-1720 ◽  
Author(s):  
Jason T. Weir ◽  
David Wheatcroft
Keyword(s):  
Species Diversity ◽  
Reproductive Isolation ◽  
New World ◽  
Latitudinal Gradient ◽  
Passerine Bird ◽  
Evolutionary Rates ◽  
High Latitudes ◽  
Rates Of Evolution ◽  
Low Latitudes ◽  
The Tropics

We ask whether rates of evolution in traits important for reproductive isolation vary across a latitudinal gradient, by quantifying evolutionary rates of two traits important for pre-mating isolation—avian syllable diversity and song length. We analyse over 2500 songs from 116 pairs of closely related New World passerine bird taxa to show that evolutionary rates for the two main groups of passerines—oscines and suboscines—doubled with latitude in both groups for song length. For syllable diversity, oscines (who transmit song culturally) evolved more than 20 times faster at high latitudes than in low latitudes, whereas suboscines (whose songs are innate in most species and who possess very simple song with few syllable types) show no clear latitudinal gradient in rate. Evolutionary rates in oscines and suboscines were similar at tropical latitudes for syllable complexity as well as for song length. These results suggest that evolutionary rates in traits important to reproductive isolation and speciation are influenced by latitude and have been fastest, not in the tropics where species diversity is highest, but towards the poles.

Into and out of the tropics: the generation of the latitudinal gradient among New World passerine birds

2014 ◽  
Vol 41 (9) ◽  
pp. 1746-1757 ◽  
Author(s):  
Jonathan D. Kennedy ◽  
Zhiheng Wang ◽  
Jason T. Weir ◽  
Carsten Rahbek ◽  
Jon Fjeldså ◽  
...  
Keyword(s):  
New World ◽  
Latitudinal Gradient ◽  
Passerine Birds ◽  
The Tropics

scholarly journals Global plant-frugivore trait matching is shaped by climate and biogeographic history

2021 ◽  
Author(s):  
Ian R. McFadden ◽  
Susanne A. Fritz ◽  
Niklaus E. Zimmermann ◽  
Loïc Pellissier ◽  
W. Daniel Kissling ◽  
...  
Keyword(s):  
Species Interactions ◽  
Latitudinal Gradient ◽  
Fruit Size ◽  
Global Scale ◽  
Frugivorous Birds ◽  
Biogeographic History ◽  
Gape Size ◽  
Avian Frugivores ◽  
Trait Structure ◽  
The Tropics

Species interactions are influenced by the trait structure of local multi-trophic communities. However, it remains unclear whether mutualistic interactions in particular can drive trait patterns at the global scale, where climatic constraints and biogeographic processes gain importance. Here we evaluate global relationships between traits of frugivorous birds and palms (Arecaceae), and how these relationships are affected, directly or indirectly, by assemblage richness, climate and biogeographic history. We leverage a new and expanded gape size dataset for nearly all avian frugivores, and find a positive relationship between gape size and fruit size, i.e., trait matching, which is influenced indirectly by palm richness and climate. We also uncover a latitudinal gradient in trait matching strength, which increases towards the tropics and varies among zoogeographic realms. Taken together, our results suggest trophic interactions have consistent influences on trait structure, but that abiotic, biogeographic and richness effects also play important, though sometimes indirect, roles in shaping the functional biogeography of mutualisms.

scholarly journals Foundation Species Across a Latitudinal Gradient in China

2020 ◽  
Author(s):  
Xiujuan Qiao ◽  
Jiaxin Zhang ◽  
Yaozhan Xu ◽  
Xiangcheng Mi ◽  
Min Cao ◽  
...  
Keyword(s):  
Species Diversity ◽  
Northern Hemisphere ◽  
Boreal Forests ◽  
Latitudinal Gradient ◽  
Basal Area ◽  
Woody Species ◽  
Foundation Species ◽  
Potential Candidate ◽  
Frequency Distributions ◽  
The Tropics

AbstractFoundation species play important roles in structuring forest communities and ecosystems. Foundation species are difficult to identify without long-term observations or experiments and their foundational roles rarely are identified before they are declining or threatened. We used new statistical criteria based on size-frequency distributions, species diversity, and spatial codispersion among woody plants to identify potential (“candidate”) foundation species in 12 large forest dynamics plots spanning 26 degrees of latitude in China. We used these data to identify a suite of candidate foundation species in Chinese forests; test the hypothesis that foundation woody plant species are more frequent in the temperate zone than in the tropics; and compare these results with comparable data from the Americas to suggest candidate foundation genera in Northern Hemisphere forests. We identified more candidate foundation species in temperate plots than in subtropical or tropical plots, and this relationship was independent of the latitudinal gradient in overall species richness. Two species of Acer, the canopy tree Acer ukurunduense and the shrubby treelet Acer barbinerve were the only two species that met both criteria in full to be considered as candidate foundation species. When we relaxed the diversity criteria, Acer, Tilia, and Juglans spp., and Corlyus mandshurica were frequently identified as candidate foundation species. In tropical plots, the tree Mezzettiopsis creaghii and the shrubs or treelets Aporusa yunnanensis and Ficus hispida had some characteristics associated with foundation species. Species diversity of co-occurring woody species was negatively associated with basal area of candidate foundation species more frequently at 5- and 10-m spatial grains (scale) than at a 20-m grain. Conversely, Bray-Curtis dissimilarity was positively associated with basal area of candidate foundation species more frequently at 5-m than at 10- or 20-m grains. Our data support the hypothesis that foundation species should be more common in temperate than in tropical or boreal forests, and suggest that in the Northern Hemisphere that Acer be investigated further as a foundation tree genus.

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