Does climate limit species richness by limiting individual species’ ranges?

Broad-scale geographical variation in species richness is strongly correlated with climate, yet the mechanisms underlying this correlation are still unclear. We test two broad classes of hypotheses to explain this pattern. Bottom-up hypotheses propose that the environment determines individual species’ ranges. Ranges then sum up to yield species richness patterns. Top-down hypotheses propose that the environment limits the number of species that occur in a region, but not which ones. We test these two classes of hypotheses using a natural experiment: seasonal changes in environmental variables and seasonal range shifts of 625 migratory birds in the Americas. We show that richness seasonally tracks the environment. By contrast, individual species’ geographical distributions do not. Rather, species occupy different sets of environmental conditions in two seasons. Our results are inconsistent with extant bottom-up hypotheses. Instead, a top-down mechanism appears to constrain the number of species that can occur in a given region.

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Environmental and Social Risks to Biodiversity and Ecosystem Health—A Bottom-Up, Resource-Focused Assessment Framework

Earth ◽

10.3390/earth2030026 ◽

2021 ◽

Vol 2 (3) ◽

pp. 440-456

Author(s):

Roger A. Pielke ◽

Jimmy Adegoke ◽

Faisal Hossain ◽

Dev Niyogi

Keyword(s):

Ecosystem Function ◽

Ecosystem Health ◽

Interactive System ◽

Integrative Approach ◽

Individual Species ◽

Assessment Framework ◽

Top Down ◽

Bottom Up ◽

Social Risks ◽

Biodiversity And Ecosystem Function

Risks from human intervention in the climate system are raising concerns with respect to individual species and ecosystem health and resiliency. A dominant approach uses global climate models to predict changes in climate in the coming decades and then to downscale this information to assess impacts to plant communities, animal habitats, agricultural and urban ecosystems, and other parts of the Earth’s life system. To achieve robust assessments of the threats to these systems in this top-down, outcome vulnerability approach, however, requires skillful prediction, and representation of changes in regional and local climate processes, which has not yet been satisfactorily achieved. Moreover, threats to biodiversity and ecosystem function, such as from invasive species, are in general, not adequately included in the assessments. We discuss a complementary assessment framework that builds on a bottom-up vulnerability concept that requires the determination of the major human and natural forcings on the environment including extreme events, and the interactions between these forcings. After these forcings and interactions are identified, then the relative risks of each issue can be compared with other risks or forcings in order to adopt optimal mitigation/adaptation strategies. This framework is a more inclusive way of assessing risks, including climate variability and longer-term natural and anthropogenic-driven change, than the outcome vulnerability approach which is mainly based on multi-decadal global and regional climate model predictions. We therefore conclude that the top-down approach alone is outmoded as it is inadequate for robustly assessing risks to biodiversity and ecosystem function. In contrast the bottom-up, integrative approach is feasible and much more in line with the needs of the assessment and conservation community. A key message of our paper is to emphasize the need to consider coupled feedbacks since the Earth is a dynamically interactive system. This should be done not just in the model structure, but also in its application and subsequent analyses. We recognize that the community is moving toward that goal and we urge an accelerated pace.

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Biogeographic and species richness patterns of Gastropoda on the southwestern Atlantic

Revista Brasileira de Biologia ◽

10.1590/s0034-71081999000400006 ◽

1999 ◽

Vol 59 (4) ◽

pp. 567-575 ◽

Cited By ~ 23

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.

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Determinants and Congruence of Species Richness Patterns across Multiple Taxonomic Groups on a Regional Scale

International Journal of Zoology ◽

10.1155/2012/297657 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Jörn Buse ◽

Eva Maria Griebeler

Keyword(s):

Land Use ◽

Species Richness ◽

Spatial Patterns ◽

Regional Scale ◽

External Validation ◽

Federal State ◽

Strongly Correlated ◽

Richness Patterns ◽

Taxonomic Groups ◽

German Federal State

Applying multiple generalized regression models, we studied spatial patterns in species richness for different taxonomic groups (amphibians, reptiles, grasshoppers, plants, mosses) within the German federal state Rhineland-Palatinate (RP). We aimed (1) to detect their centres of richness, (2) to rate the influence of climatic and land-use parameters on spatial patterns, and (3) to test whether patterns are congruent between taxonomic groups in RP. Centres of species richness differed between taxonomic groups and overall richness was the highest in the valleys of large rivers and in different areas of southern RP. Climatic parameters strongly correlated with richness in all taxa whereas land use was less significant. Spatial richness patterns of all groups were to a certain extent congruent but differed between group pairs. The number of grasshoppers strongly correlated with the number of plants and with overall species richness. An external validation corroborated the generality of our species richness models.

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Faculty Opinions recommendation of Relative strength of top-down, bottom-up, and consumer species richness effects on pond ecosystems.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1031196.363586 ◽

2006 ◽

Author(s):

Mark Gessner

Keyword(s):

Species Richness ◽

Relative Strength ◽

Top Down ◽

Bottom Up ◽

Pond Ecosystems

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Top-down and bottom-up forces in mammalian herbivore – vegetation systems: an essay review

Botany ◽

10.1139/b09-035 ◽

2009 ◽

Vol 87 (8) ◽

pp. 723-739 ◽

Cited By ~ 25

Author(s):

Roy Turkington

Keyword(s):

Field Experiments ◽

Individual Species ◽

Top Down ◽

Field Methods ◽

Bottom Up ◽

Vegetation Removal ◽

Mammalian Herbivore ◽

Resource Levels

For almost 50 years ecologists have debated why herbivores generally don’t increase in numbers to such levels as to deplete or devastate vegetation. One hypothesis is that herbivore populations are regulated at low densities by predators, and a second hypotheses is that plants are fundamentally poor food for herbivores. This has lead to two main hypotheses about the role of herbivores in structuring vegetation: the “bottom-up” and “top-down” hypotheses. Here I survey the literature, with a focus on field experiments designed to investigate the soil resource – vegetation – mammalian herbivore system, specifically asking five questions about how each trophic level responds to (i) resource addition, (ii) vegetation removal, (iii) herbivore removal or reduction, (iv) herbivore addition, and (v) the interaction of resource levels and herbivory? I use these to develop 12 testable predictions. I document the major areas of research as they relate to these 12 predictions, and use these to evaluate weaknesses and limitations in field methods. There are surprisingly few terrestrial studies that conduct factorial manipulations of multiple nutrients or herbivores, even though it is clear that these are essential. Specifically, I argue that a manipulative experimental approach is the most valuable way to advance our theory and understanding, and I advocate the continued use of long-term factorial field experiments that simultaneously manipulate soil resources levels and herbivory (preferably at multiple levels), repeated in a range of environments in which individual species or functional groups are monitored.

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Bottom-up and top-down processes influence contemporary patterns of mammal species richness in Australia's monsoonal tropics

Biological Conservation ◽

10.1016/j.biocon.2020.108638 ◽

2020 ◽

Vol 247 ◽

pp. 108638 ◽

Cited By ~ 2

Author(s):

A.M. Stobo-Wilson ◽

D. Stokeld ◽

L.D. Einoder ◽

H.F. Davies ◽

A. Fisher ◽

...

Keyword(s):

Species Richness ◽

Top Down ◽

Mammal Species ◽

Bottom Up

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Spatial Pattern of Species Richness among Terrestrial Mammals in China

Diversity ◽

10.3390/d12030096 ◽

2020 ◽

Vol 12 (3) ◽

pp. 96

Author(s):

Yao Chi ◽

Jiechen Wang ◽

Changbai Xi ◽

Tianlu Qian ◽

Caiying Sheng

Keyword(s):

Species Richness ◽

Spatial Pattern ◽

Large Scale ◽

Negative Relationship ◽

Geographical Information ◽

Western China ◽

Strongly Correlated ◽

Terrestrial Mammals ◽

Richness Patterns ◽

Forested Ecosystems

We describe large-scale patterns of terrestrial mammal distribution in China by using geographical information system (GIS) spatial analysis. Mammal taxa, examined by species, family, and order, were binned into 10 km × 10 km grids to explore the relationship between their spatial distribution and geographical factors potentially affecting the same. The spatial pattern of species richness revealed four agglomerations: high richness in the south, low in north, and two low richness areas in eastern and western China. Species richness patterns in Carnivora was the most similar to overall terrestrial mammals’ richness; however, species richness in different orders exhibited distributions distinct from the overall pattern. We found a negative relationship between richness and latitude gradient. Species richness was most strongly correlated with forested ecosystems, and was found to be higher at an elevation of 2000~2200 m, with greater altitudinal variation indicative of higher species richness.

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On the expected distribution of species' ranges

Paleobiology ◽

10.1017/s0094837300011878 ◽

1988 ◽

Vol 14 (2) ◽

pp. 126-138 ◽

Cited By ~ 27

Author(s):

Carl F. Koch ◽

John P. Morgan

Keyword(s):

Species Richness ◽

Sample Size ◽

Species Range ◽

Data Set ◽

Species Ranges ◽

Richness Patterns ◽

Fossil Data

A method is provided to calculate the expected distribution of species' ranges for use as a basis of comparison for paleontological interpretation of species' range charts. If the method is used for such studies, the possibility of suggesting an environmental or biological cause for observed patterns, when in fact no such cause exists, will be diminished. The method is applied to a large, well-studied fossil data set to illustrate some possible species' range patterns which result only from sample size inequities. As examples, stepwise extinction and species richness patterns are predicted for situations where, in reality, none exist.

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