Predicting Global Biodiversity Patterns from Theory

2018 ◽  
pp. 124-148
Author(s):  
Boris Worm ◽  
Derek P. Tittensor
Keyword(s):  
Species Richness ◽  
Theoretical Model ◽  
Deep Sea ◽  
Global Theory ◽  
Equal Area ◽  
Terrestrial Habitats ◽  
Global Biodiversity ◽  
Declining Species ◽  
The Tropics

The previous chapter developed a global theory of biodiversity incorporating gradients in ambient temperature and habitat area or productivity. It showed that a metacommunity model implementation of the theory can reproduce first-order patterns of declining species richness from the tropics to the poles in an idealized cylindrical ocean. This chapter tests the theory in a more realistic setting by fitting the neutral-metabolic metacommunity model to a global equal-area grid with a more realistic spatial structure. The rationale here is to explore whether the communities that evolve in a simple theoretical model can reproduce observed patterns of species richness in the real world, and reconcile the contrasting patterns seen in coastal, pelagic, deep-sea, and terrestrial habitats.

Observed Patterns of Global Biodiversity

2018 ◽  
pp. 10-53
Author(s):  
Boris Worm ◽  
Derek P. Tittensor
Keyword(s):  
Species Richness ◽  
Deep Sea ◽  
Biodiversity Patterns ◽  
Space And Time ◽  
Marine Realm ◽  
Species Groups ◽  
Global Biodiversity ◽  
Biodiversity Changes ◽  
Terrestrial Biodiversity ◽  
Unimodal Pattern

This chapter summarizes and synthesizes known biodiversity patterns, and analyzes them for congruency over space and time. The discussion is limited to macroecological patterns at continental to global scales (thousands of km). The chapter also focuses on the simplest measure of biodiversity—namely, species richness. The discussions cover marine coastal biodiversity, marine pelagic biodiversity, deep-sea biodiversity, terrestrial biodiversity, changes in biodiversity patterns through time, and robustness of documented biodiversity patterns. Among the findings is that averaging across all known species groups on land and in the sea, tropical peaks in species richness were as common as subtropical peaks, whereas species groups cresting in temperate or polar latitudes were more exceptional. Thus, the oft-cited unimodal pattern of biodiversity appears frequently, particularly on land, but there is also evidence that supports a newly emerging paradigm of asymmetric unimodal or bimodal peaks often in the subtropics, and particularly in the marine realm.

scholarly journals Low-latitude climate variability in the Heinrich frequency band of the Late Cretaceous greenhouse world

2014 ◽  
Vol 10 (3) ◽  
pp. 1001-1015 ◽  
Author(s):  
N. J. de Winter ◽  
C. Zeeden ◽  
F. J. Hilgen
Keyword(s):  
Deep Sea ◽  
Linear Response ◽  
Elemental Abundance ◽  
Milankovitch Cycles ◽  
Glacial Cycle ◽  
Low Latitude ◽  
Project Site ◽  
The Tropics ◽  
The Last Glacial ◽  
Drilling Project

Abstract. Deep marine successions of early Campanian age from DSDP (Deep Sea Drilling Project) site 516F drilled at low paleolatitudes in the South Atlantic reveal distinct sub-Milankovitch variability in addition to precession, obliquity and eccentricity-related variations. Elemental abundance ratios point to a similar climatic origin for these variations and exclude a quadripartite structure as an explanation for the inferred semi-precession cyclicity in the magnetic susceptibility (MS) signal as observed in the Mediterranean Neogene for precession-related cycles. However, semi-precession cycles as suggested by previous work are likely an artifact reflecting the first harmonic of the precession signal. The sub-Milankovitch variability, especially in MS, is best approximated by a ~7 kyr cycle as shown by spectral analysis and bandpass filtering. The presence of sub-Milankovitch cycles with a period similar to that of Heinrich events of the last glacial cycle is consistent with linking the latter to low-latitude climate change caused by a non-linear response to precession-induced variations in insolation between the tropics.

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.

Developing a Theory of Global Biodiversity

2018 ◽  
pp. 93-123
Author(s):  
Boris Worm ◽  
Derek P. Tittensor
Keyword(s):  
Species Richness ◽  
First Principles ◽  
Predictive Power ◽  
Global Distribution ◽  
Biodiversity Patterns ◽  
Modeling Approach ◽  
Possibility Space ◽  
Competing Hypotheses ◽  
Global Biodiversity

This chapter develops a body of theory to capture and test the key processes governing the global distribution of biodiversity. From this theory, it devises a spatial metacommunity model that enables the reconstruction of documented patterns of species richness from first principles and the prediction of their major features. The chapter starts with a simple, flexible, and tractable framework that can be built on and expanded in order to test competing hypotheses. This modeling approach may be described as an experimental toolbox for global biodiversity patterns. The aim is not necessarily to achieve the highest predictive power, but to explore the possibility space of global biodiversity patterns and their drivers.

From Mission to Electoral Strategy

2016 ◽  
Author(s):  
Heath Brown
Keyword(s):  
Theoretical Model ◽  
Nonprofit Organizations ◽  
Survey Methodology ◽  
Voter Registration ◽  
Organizational Resources ◽  
Empirical Measurement ◽  
Voting Procedures

This chapter operationalizes the grounded theoretical model discussed in the previous chapter with an empirical measurement of the various factors it focuses on. It explains the survey methodology used to field a questionnaire to eleven hundred nonprofit organizations in the six states, then analyzes the data collected from survey respondents with a particular focus on the first part of the theory of immigrant-serving nonprofit engagement. The evidence shows that aspects of mission, organizational resources, and policy relate to which electoral tactics an immigrant-serving nonprofit makes use of. Most significantly, the new law to tighten voting procedures in Florida reduced the likelihood that organizations in that state held voter registration drives.

scholarly journals Biogeographic and species richness patterns of Gastropoda on the southwestern Atlantic

1999 ◽  
Vol 59 (4) ◽  
pp. 567-575 ◽  
Author(s):  
S. R. FLOETER ◽  
A. SOARES-GOMES
Keyword(s):  
Species Richness ◽  
Transition Zone ◽  
Rio Grande ◽  
Distribution Patterns ◽  
Southwestern Atlantic ◽  
Rio Grande Do Sul ◽  
Biogeographic Province ◽  
Number Of Species ◽  
Richness Patterns ◽  
The Tropics

Patterns of richness and biogeography of Gastropoda molluscs were determined based on lists of species from five sites along the southwestern Atlantic. The analysis of the distribution patterns of these sites confirmed the existence of a broader transition zone between southern Espírito Santo State (21°S) and Rio Grande do Sul State (32°S). This zone is very heterogeneous, presenting a low endemism rate and a significant number of species common to the near provinces, and does not show enough consistency to be considered as an independent biogeographic province as proposed by Palacio (1980). Observing the distribution of species along the southwestern Atlantic we find an increase in the proportion of species with greatest latitudinal ranges (occurring from the tropics to Patagonia) from lowest to highest latitudes, following Rappoport's rule.

scholarly journals Discovery of widely available abyssal rock patches reveals overlooked habitat type and prompts rethinking deep-sea biodiversity

2020 ◽  
Vol 117 (27) ◽  
pp. 15450-15459 ◽  
Author(s):  
Torben Riehl ◽  
Anne-Cathrin Wölfl ◽  
Nico Augustin ◽  
Colin W. Devey ◽  
Angelika Brandt
Keyword(s):  
Species Richness ◽  
Deep Sea ◽  
Habitat Heterogeneity ◽  
Habitat Type ◽  
Substrate Availability ◽  
Fracture Zones ◽  
Geographic Patterns ◽  
Faunal Diversity ◽  
Sediment Variability ◽  
Seafloor Sediment

Habitat heterogeneity and species diversity are often linked. On the deep seafloor, sediment variability and hard-substrate availability influence geographic patterns of species richness and turnover. The assumption of a generally homogeneous, sedimented abyssal seafloor is at odds with the fact that the faunal diversity in some abyssal regions exceeds that of shallow-water environments. Here we show, using a ground-truthed analysis of multibeam sonar data, that the deep seafloor may be much rockier than previously assumed. A combination of bathymetry data, ruggedness, and backscatter from a trans-Atlantic corridor along the Vema Fracture Zone, covering crustal ages from 0 to 100 Ma, show rock exposures occurring at all crustal ages. Extrapolating to the whole Atlantic, over 260,000 km2of rock habitats potentially occur along Atlantic fracture zones alone, significantly increasing our knowledge about abyssal habitat heterogeneity. This implies that sampling campaigns need to be considerably more sophisticated than at present to capture the full deep-sea habitat heterogeneity and biodiversity.

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.

Patterns of Distribution of Acacia in Australia

1988 ◽  
Vol 36 (4) ◽  
pp. 385 ◽  
Author(s):  
BR Maslin ◽  
L Pedley
Keyword(s):  
Species Richness ◽  
Western Australia ◽  
Arid Zone ◽  
Patterns Of Distribution ◽  
The North ◽  
Geographic Patterns ◽  
South West ◽  
Eastern Australia ◽  
Semiarid Areas ◽  
The Tropics

Patterns of distribution are described for the three subgenera and nine sections that make up the Australian Acacia flora. Subgenus Phyllodineae (833 species) is widespread and contains 99% of the species; subgenus Acacia (six species) and subgenus Aculeiferum (one species) are poorly represented and virtually confined to the north of the continent. The geographic patterns of species-richness are strongly influenced by sections Phyllodineae (352 species), Juliflorae (219 species) and Plurinerves (178 species). Section Phyllodineae has centres of richness south of the Tropic of Capricorn in temperate and adjacent semiarid areas of eastern, south-eastern and south-western Australia. The section is poorly represented in the tropics. The closely related sections Juliflorae and Plurinerves predominate in the north of the continent, semiarid areas of the south-west, many rocky tablelands of the Arid Zone and along the Great Dividing Range and adjacent inland riverine lowland areas in eastern Australia. The remaining four sections contribute little to the overall patterns of species-richness. The principal speciespoor areas are sandy and fluvial lowland regions of the Arid Zone. In eastern Australia, sections Botrycephalae, Juliflorae, Phyllodineae and Plurinerves show discontinuous patterns of species-richness along the Great Dividing Range. All sections have species whose ranges terminate in the area of the McPherson-Macleay Overlap region.

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