scholarly journals Richness and phylogenetic diversity are affected by space and time in the megadiverse Atlantic Forest of South America

Author(s):  
José Thales da Motta Portillo ◽  
Fausto Erritto Barbo ◽  
Josué Anderson Rêgo Azevedo ◽  
Ricardo Jannini Sawaya

Understanding variation of species richness along latitudinal gradients, with more species toward the tropics, represents a challenge for ecologists. Species richness also varies according to the available area, with more species in larger regions, with area and latitude posited as major drivers of richness variations. However, species richness does not fully capture the evolutionary history behind those patterns. Phylogenetic diversity can provide insights on the role of time and evolutionary drivers of environmental gradients. We analyzed here the latitudinal gradient of endemic snakes from the Atlantic Forest of South America, a megadiverse and highly threatened portion of the Neotropics. We assessed the effect of area and average clade age on species richness and phylogenetic diversity, testing whether species richness and phylogenetic diversity increase with area availability and in lower latitudes. We found that area can predict species richness, but not phylogenetic diversity. Brazilian southeastern mountain ranges include larger patches of Atlantic Forest and the highest richness levels, but generally harboring snakes from relatively recent clades (neoendemics). There is a negative relationship between species richness and average clade age along the latitudinal gradient, with older clades found mainly in northern portions, increasing phylogenetic diversity at lower latitudes. Different dimensions of diversity, species richness and phylogenetic diversity, are thus affected in different ways by area and time for speciation in the Atlantic Forest, and this may be a trend in highly diverse tropical regions.

2018 ◽  
Author(s):  
José Thales da Motta Portillo ◽  
Fausto Erritto Barbo ◽  
Josué Anderson Rêgo Azevedo ◽  
Ricardo Jannini Sawaya

Understanding variation of species richness along latitudinal gradients, with more species toward the tropics, represents a challenge for ecologists. Species richness also varies according to the available area, with more species in larger regions, with area and latitude posited as major drivers of richness variations. However, species richness does not fully capture the evolutionary history behind those patterns. Phylogenetic diversity can provide insights on the role of time and evolutionary drivers of environmental gradients. We analyzed here the latitudinal gradient of endemic snakes from the Atlantic Forest of South America, a megadiverse and highly threatened portion of the Neotropics. We assessed the effect of area and average clade age on species richness and phylogenetic diversity, testing whether species richness and phylogenetic diversity increase with area availability and in lower latitudes. We found that area can predict species richness, but not phylogenetic diversity. Brazilian southeastern mountain ranges include larger patches of Atlantic Forest and the highest richness levels, but generally harboring snakes from relatively recent clades (neoendemics). There is a negative relationship between species richness and average clade age along the latitudinal gradient, with older clades found mainly in northern portions, increasing phylogenetic diversity at lower latitudes. Different dimensions of diversity, species richness and phylogenetic diversity, are thus affected in different ways by area and time for speciation in the Atlantic Forest, and this may be a trend in highly diverse tropical regions.


Science ◽  
2019 ◽  
Vol 363 (6425) ◽  
pp. eaat4220 ◽  
Author(s):  
John M. Grady ◽  
Brian S. Maitner ◽  
Ara S. Winter ◽  
Kristin Kaschner ◽  
Derek P. Tittensor ◽  
...  

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.


2014 ◽  
Vol 11 (5) ◽  
pp. 7055-7077 ◽  
Author(s):  
G. Tang ◽  
M. G. Zhang ◽  
C. Liu ◽  
Z. Zhou ◽  
W. Chen ◽  
...  

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.


2020 ◽  
Author(s):  
Ricardo A. Segovia ◽  
Andy R. Griffiths ◽  
Diego Arenas ◽  
A. A. Piyali Dias ◽  
Kyle G. Dexter

AbstractExtratropical angiosperm diversity is thought to have arisen from lineages that originated in the more diverse tropics, but studies of dispersal between tropical and extratropical environments and their consequences for diversification are rare. In order to understand the evolutionary effects of shifts between the tropics and extratropics, defined here as areas that do versus do not regularly experience freezing temperatures, we studied the biogeographic history and associated diversification patterns of Cunoniaceae. We mapped the distribution of all species in the family and combined this with a newly constructed phylogeny for the family. The family shows a long evolutionary association with both tropical and extratropical environments, the tropics house considerably greater species richness of Cunoniaceae. Indeed, both tropical and extratropical environments appear to have had a similar number of lineages until 12 Ma, after which time the number of lineages in tropical areas increased at a faster rate. In addition, community phylogenetic approaches show that tropical regions have markedly less phylogenetic diversity than expected given their species richness, which is further suggestive of recent species radiations in tropical areas. The Cunoniaceae show an atypical pattern for angiosperms of frequent shifts between tropical and extratropical environments, but despite this, shows a more conventional pattern of higher, although recent, diversification rates in the tropics. Our results support the idea that high angiosperm species richness in the tropics may result from the tropics acting as a cradle of recent angiosperm diversification.


2015 ◽  
Vol 282 (1819) ◽  
pp. 20151589 ◽  
Author(s):  
Alyssa R. Cirtwill ◽  
Daniel B. Stouffer ◽  
Tamara N. Romanuk

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.


2007 ◽  
Vol 274 (1618) ◽  
pp. 1567-1574 ◽  
Author(s):  
Kevin J Gaston ◽  
Richard G Davies ◽  
C. David L Orme ◽  
Valerie A Olson ◽  
Gavin H Thomas ◽  
...  

Despite its wide implications for many ecological issues, the global pattern of spatial turnover in the occurrence of species has been little studied, unlike the global pattern of species richness. Here, using a database on the breeding distributions of birds, we present the first global maps of variation in spatial turnover for an entire taxonomic class, a pattern that has to date remained largely a matter of conjecture, based on theoretical expectations and extrapolation of inconsistent patterns from different biogeographic realms. We use these maps to test four predictions from niche theory as to the form that this variation should take, namely that turnover should increase with species richness, towards lower latitudes, and with the steepness of environmental gradients and that variation in turnover is determined principally by rare (restricted) species. Contrary to prediction, we show that turnover is high both in areas of extremely low and high species richness, does not increase strongly towards the tropics, and is related both to average environmental conditions and spatial variation in those conditions. These results are closely associated with a further important and novel finding, namely that global patterns of spatial turnover are driven principally by widespread species rather than the restricted ones. This complements recent demonstrations that spatial patterns of species richness are also driven principally by widespread species, and thus provides an important contribution towards a unified model of how terrestrial biodiversity varies both within and between the Earth's major land masses.


2014 ◽  
Vol 112 (2) ◽  
pp. 442-447 ◽  
Author(s):  
Matthew L. Forister ◽  
Vojtech Novotny ◽  
Anna K. Panorska ◽  
Leontine Baje ◽  
Yves Basset ◽  
...  

Understanding variation in resource specialization is important for progress on issues that include coevolution, community assembly, ecosystem processes, and the latitudinal gradient of species richness. Herbivorous insects are useful models for studying resource specialization, and the interaction between plants and herbivorous insects is one of the most common and consequential ecological associations on the planet. However, uncertainty persists regarding fundamental features of herbivore diet breadth, including its relationship to latitude and plant species richness. Here, we use a global dataset to investigate host range for over 7,500 insect herbivore species covering a wide taxonomic breadth and interacting with more than 2,000 species of plants in 165 families. We ask whether relatively specialized and generalized herbivores represent a dichotomy rather than a continuum from few to many host families and species attacked and whether diet breadth changes with increasing plant species richness toward the tropics. Across geographic regions and taxonomic subsets of the data, we find that the distribution of diet breadth is fit well by a discrete, truncated Pareto power law characterized by the predominance of specialized herbivores and a long, thin tail of more generalized species. Both the taxonomic and phylogenetic distributions of diet breadth shift globally with latitude, consistent with a higher frequency of specialized insects in tropical regions. We also find that more diverse lineages of plants support assemblages of relatively more specialized herbivores and that the global distribution of plant diversity contributes to but does not fully explain the latitudinal gradient in insect herbivore specialization.


2014 ◽  
Vol 64 (2) ◽  
pp. 141-150 ◽  
Author(s):  
Ana Cristina L. Garcia ◽  
Edson S.B. Leal ◽  
Claudia Rohde ◽  
Francisco G. Carvalho-Neto ◽  
Martín A. Montes

Due to the lack of studies with a regional focus on the richness and distribution of the fauna of chiropterans in northeastern Brazil, this paper presents a collection of these data gathered in an extensive literature review. The data analyzed include technical reports of environment consulting agencies, abstracts presented in scientific meetings, monographs, dissertations, theses, papers, scientific notes, short communications, book chapters and books on bats of South America, Brazil and the biomes Amazon, Caatinga, Cerrado and Atlantic Forest. The numbers of municipalities surveyed per biome and the localities, municipalities and species richness for each state and biome in northeastern Brazil were determined. This information indicated the regions lacking more consistent Chiroptera sampling efforts, namely large areas in the Amazon, Caatinga and Cerrado. However, bat surveys in Atlantic Forest environments in most northeastern Brazilian states were considered representative. Although bat populations in some states have been poorly surveyed, the results of this review afford to conclude that a large part of the diversity of bat species known in Brazil has been reported for the northeastern region of the country. This review enlarges the knowledge on bat species richness and distribution in northeastern Brazil, and indicates areas suffering from wide survey gaps.


2016 ◽  
Vol 283 (1830) ◽  
pp. 20153027 ◽  
Author(s):  
Adam Tomašových ◽  
Jonathan D. Kennedy ◽  
Tristan J. Betzner ◽  
Nicole Bitler Kuehnle ◽  
Stewart Edie ◽  
...  

Many marine and terrestrial clades show similar latitudinal gradients in species richness, but opposite gradients in range size—on land, ranges are the smallest in the tropics, whereas in the sea, ranges are the largest in the tropics. Therefore, richness gradients in marine and terrestrial systems do not arise from a shared latitudinal arrangement of species range sizes. Comparing terrestrial birds and marine bivalves, we find that gradients in range size are concordant at the level of genera. Here, both groups show a nested pattern in which narrow-ranging genera are confined to the tropics and broad-ranging genera extend across much of the gradient. We find that (i) genus range size and its variation with latitude is closely associated with per-genus species richness and (ii) broad-ranging genera contain more species both within and outside of the tropics when compared with tropical- or temperate-only genera. Within-genus species diversification thus promotes genus expansion to novel latitudes. Despite underlying differences in the species range-size gradients, species-rich genera are more likely to produce a descendant that extends its range relative to the ancestor's range. These results unify species richness gradients with those of genera, implying that birds and bivalves share similar latitudinal dynamics in net species diversification.


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