scholarly journals Species-area and network-area relationships in host–helminth interactions

2021 ◽  
Vol 288 (1947) ◽  
Author(s):  
Tad A. Dallas ◽  
Pedro Jordano
Keyword(s):  
Species Richness ◽  
Trophic Interactions ◽  
Species Interactions ◽  
Geographical Area ◽  
Species Interaction ◽  
Helminth Parasites ◽  
Scaling Relationship ◽  
Theoretical Predictions ◽  
Species Area ◽  
Network Area

The scaling relationship observed between species richness and the geographical area sampled (i.e. the species-area relationship (SAR)) is a widely recognized macroecological relationship. Recently, this theory has been extended to trophic interactions, suggesting that geographical area may influence the structure of species interaction networks (i.e. network-area relationships (NARs)). Here, we use a global dataset of host–helminth parasite interactions to test existing predictions from macroecological theory. Scaling between single locations to the global host–helminth network by sequentially adding networks together, we find support that geographical area influences species richness and the number of species interactions in host–helminth networks. However, species-area slopes were larger for host species relative to their helminth parasites, counter to theoretical predictions. Lastly, host–helminth network modularity—capturing the tendency of the network to form into separate subcommunities—decreased with increasing area, also counter to theoretical predictions. Reconciling this disconnect between existing theory and observed SAR and NAR will provide insight into the spatial structuring of ecological networks, and help to refine theory to highlight the effects of network type, species distributional overlap, and the specificity of trophic interactions on NARs.

scholarly journals Species-area relationships emerge from multiple coexistence mechanisms

2021 ◽  
Author(s):  
David Garcia-Callejas ◽  
Ignasi Bartomeus ◽  
Oscar Godoy
Keyword(s):  
Species Richness ◽  
Spatial Heterogeneity ◽  
Species Interactions ◽  
Spatial Scales ◽  
Single Species ◽  
Small Population ◽  
Collective Effects ◽  
Demographic Stochasticity ◽  
Species Dominance ◽  
Species Area

The increase of species richness with area is a universal phenomenon on Earth. However, this observation contrasts with our poor understanding of how these species-area relationships (SARs) emerge from the collective effects of area, spatial heterogeneity, and local interactions. By combining a structuralist approach with five years of empirical observations in a highly-diverse grassland, we show that,contrary to expectations, spatial heterogeneity plays a little role in the accumulation of species richness with area in our system. Instead, as we increase the sampled area more species combinations are realized, and they coexist mainly due to direct pairwise interactions rather than by changes in single-species dominance or by indirect interactions. We also identify a small set of transient species with small population sizes that are consistently found across spatial scales. These findings empirically support the importance of the architecture of species interactions together with demographic stochasticity for driving SARs.

Patterns of biological diversity

2019 ◽  
pp. 11-37
Author(s):  
Gary G. Mittelbach ◽  
Brian J. McGill
Keyword(s):  
Species Richness ◽  
Species Interactions ◽  
Biological Diversity ◽  
Spatial Scales ◽  
Species Numbers ◽  
Diversity Gradient ◽  
Species Abundances ◽  
Species Area ◽  
Species Area Relationship ◽  
The Relationship

This chapter examines how biodiversity, the variety of life, is distributed across the globe and within local communities. It begins by considering some of the challenges associated with assessing biological diversity at different spatial scales. Then, three of the best-studied patterns in species richness are examined in detail—the species–area relationship, the distribution of species abundances, and the relationship between productivity and species richness. The chapter concludes with a detailed exploration of the most dramatic of Earth’s biodiversity patterns—the latitudinal diversity gradient. The above patterns constitute much of what community ecology seeks to explain about nature. Their study provides a foundation from which to explore mechanisms of species interactions, and to understand the processes that drive variation in species numbers and their distribution.

scholarly journals The spatial configuration of biotic interactions shapes coexistence-area relationships in an annual plant community

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
David García-Callejas ◽  
Ignasi Bartomeus ◽  
Oscar Godoy
Keyword(s):  
Species Richness ◽  
Spatial Heterogeneity ◽  
Species Interactions ◽  
Spatial Configuration ◽  
Spatial Scales ◽  
Single Species ◽  
Small Population ◽  
Collective Effects ◽  
Species Dominance ◽  
Species Area

AbstractThe increase of species richness with area is a universal phenomenon on Earth. However, this observation contrasts with our poor understanding of how these species-area relationships (SARs) emerge from the collective effects of area, spatial heterogeneity, and local interactions. By combining a structuralist approach with five years of empirical observations in a highly-diverse Mediterranean grassland, we show that spatial heterogeneity plays a little role in the accumulation of species richness with area in our system. Instead, as we increase the sampled area more species combinations are realized, and they coexist mainly due to direct pairwise interactions rather than by changes in single-species dominance or by indirect interactions. We also identify a small set of transient species with small population sizes that are consistently found across spatial scales. These findings empirically support the importance of the architecture of species interactions together with stochastic events for driving coexistence- and species-area relationships.

scholarly journals Facilitation costs and benefits function simultaneously on stress gradients for animals

2018 ◽  
Vol 285 (1885) ◽  
pp. 20180983 ◽  
Author(s):  
Olivier Dangles ◽  
Mario Herrera ◽  
Carlos Carpio ◽  
Christopher J. Lortie
Keyword(s):  
Conceptual Framework ◽  
Environmental Conditions ◽  
Species Interactions ◽  
Stress Gradient ◽  
Species Interaction ◽  
Positive Interactions ◽  
Costs And Benefits ◽  
Strong Basis ◽  
Stress Gradients ◽  
High Resource

Understanding the variation in species interactions along environmental stress gradients is crucial for making robust ecological predictions about community responses to changing environmental conditions. The facilitation–competition framework has provided a strong basis for predictions (e.g. the stress-gradient hypothesis, SGH), yet the mechanisms behind patterns in animal interactions on stress gradients are poorly explored in particular for mobile animals. Here, we proposed a conceptual framework modelling changes in facilitation costs and benefits along stress gradients and experimentally tested this framework by measuring fitness outcomes of benefactor–beneficiary interactions across resource quality levels. Three arthropod consumer models from a broad array of environmental conditions were used including aquatic detritivores, potato moths and rainforest carrion beetles. We detected a shift to more positive interactions at increasing levels of stress thereby supporting the application of the SGH to mobile animals. While most benefactors paid no significant cost of facilitation, an increase in potato moth beneficiary's growth at high resource stress triggered costs for benefactors. This study is the first to experimentally show that both costs and benefits function simultaneously on stress gradients for animals. The proposed conceptual framework could guide future studies examining species interaction outcomes for both animals and plants in an increasingly stressed world.

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.

Biogeography of island floras in the Great Lakes. I. Species richness and composition in relation to gull nesting activities

1989 ◽  
Vol 67 (4) ◽  
pp. 961-969 ◽  
Author(s):  
E. H. Hogg ◽  
J. K. Morton ◽  
Joan M. Venn
Keyword(s):  
Species Richness ◽  
Great Lakes ◽  
Plant Species ◽  
Vascular Plants ◽  
Soil Nutrient ◽  
Lake Huron ◽  
Great Lakes Region ◽  
Alien Plant ◽  
Species Area ◽  
The Difference

Species–area relations of vascular plants and the effect of nesting colonies of gulls on plant species composition were investigated for 77 islands in Georgian Bay and Lake Huron in the Great Lakes region of Canada. The percentage of plant species classed as alien, annual, or biennial was significantly greater on islands with gull colonies. The slope of the species–area curve was significantly steeper on islands supporting gull colonies compared with islands lacking gull colonies. The expected decline in species richness with increased island remoteness was not detected statistically using multiple regression analysis. The difference in species–area slopes does not appear to reflect a lower propagule immigration rate to islands with gull colonies, because gulls are important in the dispersal of alien plant species to these islands. Larger islands with gull colonies tended to have richer floras than islands of similar size without gull colonies. It is suggested that on these larger islands the presence of gull colonies produces a gradient of soil nutrient and disturbance regimes, thus increasing habitat heterogeneity and species richness.

scholarly journals Species Richness of the Family Ericaceae along an Elevational Gradient in Yunnan, China

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 511 ◽  
Author(s):  
Ji-Hua Wang ◽  
Yan-Fei Cai ◽  
Lu Zhang ◽  
Chuan-Kun Xu ◽  
Shi-Bao Zhang
Keyword(s):  
Species Richness ◽  
Environmental Gradients ◽  
Variation Partitioning ◽  
Elevational Gradient ◽  
Geometric Constraints ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
The Family ◽  
Species Area ◽  
Upper Third

Knowledge about how species richness varies along spatial and environmental gradients is important for the conservation and use of biodiversity. The Ericaceae is a major component of alpine and subalpine vegetation globally. However, little is known about the spatial pattern of species richness and the factors that drive that richness in Ericaceae. We investigated variation in species richness of Ericaceae along an elevational gradient in Yunnan, China, and used a variation partitioning analysis based on redundancy analysis ordination to examine how those changes might be influenced by the mid-domain effect, the species-area relationship, and climatic variables. Species richness varied significantly with elevation, peaking in the upper third of the elevational gradient. Of the factors examined, climate explained a larger proportion of the variance in species richness along the elevational gradient than either land area or geometric constraints. Species richness showed a unimodal relationship with mean annual temperature and mean annual precipitation. The elevational pattern of species richness for Ericaceae was shaped by the combined effects of climate and competition. Our findings contribute to a better understanding of the potential effects of climate change on species richness for Ericaceae.

Key Species Superpose the Effect of Species Richness and Species Interaction on Carbon Fluxes in a Restored Minerotrophic Peatland

Wetlands ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 333-349 ◽  
Author(s):  
Golnoush Hassanpour Fard ◽  
Elena Farries ◽  
Vicky Bérubé ◽  
Line Rochefort ◽  
Maria Strack
Keyword(s):  
Species Richness ◽  
Carbon Fluxes ◽  
Species Interaction ◽  
Key Species ◽  
Minerotrophic Peatland

Hot-Spot Facts and Artifacts-Questioning Israel's Great Biodiversity

2009 ◽  
Vol 55 (3) ◽  
pp. 263-279 ◽  
Author(s):  
Uri Roll ◽  
Lewi Stone ◽  
Shai Meiri
Keyword(s):  
Species Richness ◽  
Biological Diversity ◽  
Hot Spot ◽  
Flowering Plants ◽  
Prediction Intervals ◽  
Predicting Factors ◽  
Mediterranean Countries ◽  
Species Area ◽  
Expected Values ◽  
Species Area Relationship

Israel's biological diversity has been praised as being particularly rich in relation to its size; however this assumption was never tested when taking into account the empirical form of the species-area relationship. Here we compared the species richness of different countries to see if the Israeli diversity is exceptionally rich when area is accurately accounted for. We compared richness of amphibians, birds, mammals, reptiles, flowering plants, conifers and cycads, and ferns in all the world's countries. We further tested the effects of mean latitude, altitude span, and insularity on species richness both for all world countries and just for Mediterranean countries. For all taxa and in all tests, Israel lies within the prediction intervals of the models. Out of 42 tests, Israel's residuals lie in the upper decile of positive residuals once: for reptiles, when compared to all world countries, taking all predicting factors into account. Using only countries larger than 1000 km2, Israel was placed as top residual when compared to other Mediterranean countries for mammals and reptiles. We therefore conclude that Israel's species richness does not significantly exceed the expected values for a country its size. This is true when comparing it to either world or just Mediterranean countries. Adding more predicting factors does not change this fact.

scholarly journals Avian species–area relationships indicate that towns are not different from natural areas

2018 ◽  
Vol 45 (4) ◽  
pp. 419-424 ◽  
Author(s):  
SIMONE FATTORINI ◽  
GIULIA LIN ◽  
CRISTINA MANTONI
Keyword(s):  
Species Richness ◽  
Urban Areas ◽  
Bird Species ◽  
Avian Species ◽  
Conservation Priorities ◽  
Natural Areas ◽  
Bird Richness ◽  
Negative Effect ◽  
Species Area ◽  
Human Density

SUMMARYUrban areas host many bird species, and urban species richness can be compared with that in natural areas using species–area relationships (SARs). We used a multimodel selection approach to investigate the influence of area, human population, elevation and climatic variables on species richness of breeding birds from 34 towns and 54 nature reserves in Italy. Using the linearized power function, area was identified as the most important correlate of avian species richness in both urban and natural areas. The SARs did not differ significantly between towns and reserves, although human density had a negative effect on bird richness. These findings underline the possible importance of urban areas in biodiversity conservation, but also stress that human density is a factor reducing species richness. However, species richness alone cannot inform conservation priorities because it does not take into account the different conservation values of species.

Sign in / Sign up

Export Citation Format

Share Document