The evolutionary assembly of forest communities along environmental gradients: recent diversification or sorting of pre-adapted clades?

AbstractHistorical biogeographic events such as mountain orogeny are associated with the creation of environmental gradients, giving rise to the assembly of communities of species observed today. However, key gaps remain in our understanding of the relative importance of different eco-evolutionary processes acting as drivers of community assembly across environmental gradients. In this study, we test two non-exclusive hypotheses of the eco-evolutionary processes that shape tree communities across the Central Andean elevational gradient: Communities are assembled via 1) immigration and ecological sorting of pre-adapted clades, and 2) recent adaptive diversification along the elevational gradient. We used species surveys in the Bolivian and Peruvian Andes and a novel phylogenetic framework to test the relative importance of these hypotheses. Although adaptive diversification has previously been observed in specific clades, immigration and sorting of clades pre-adapted to montane habitats is the primary mechanism shaping communities across elevations.

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A new method for quantifying heterochrony in evolutionary lineages

Paleobiology ◽

10.1017/pab.2020.17 ◽

2020 ◽

pp. 1-22 ◽

Cited By ~ 3

Author(s):

James C. Lamsdell

Keyword(s):

Environmental Gradients ◽

Morphological Changes ◽

Morphological Characteristics ◽

Environmental Pressures ◽

Primary Mechanism ◽

Phylogenetic Framework ◽

Morphological Variants ◽

Organismal Development ◽

Internal Relationships ◽

Evolutionary Lineages

Abstract The occupation of new environments by evolutionary lineages is frequently associated with morphological changes. This covariation of ecotype and phenotype is expected due to the process of natural selection, whereby environmental pressures lead to the proliferation of morphological variants that are a better fit for the prevailing abiotic conditions. One primary mechanism by which phenotypic variants are known to arise is through changes in the timing or duration of organismal development resulting in alterations to adult morphology, a process known as heterochrony. While numerous studies have demonstrated heterochronic trends in association with environmental gradients, few have done so within a phylogenetic context. Understanding species interrelationships is necessary to determine whether morphological change is due to heterochronic processes; however, research is hampered by the lack of a quantitative metric with which to assess the degree of heterochronic traits expressed within and among species. Here I present a new metric for quantifying heterochronic change, expressed as a heterochronic weighting, and apply it to xiphosuran chelicerates within a phylogenetic context to reveal concerted independent heterochronic trends. These trends correlate with shifts in environmental occupation from marine to nonmarine habitats, resulting in a macroevolutionary ratchet. Critically, the distribution of heterochronic weightings among species shows evidence of being influenced by both historical, phylogenetic processes and external ecological pressures. Heterochronic weighting proves to be an effective method to quantify heterochronic trends within a phylogenetic framework and is readily applicable to any group of organisms that have well-defined morphological characteristics, ontogenetic information, and resolved internal relationships.

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Dimensions of passerine biodiversity along an elevational gradient: a nexus for historical biogeography and contemporary ecology

10.1101/842138 ◽

2019 ◽

Author(s):

Kevin R. Burgio ◽

Steven J. Presley ◽

Laura M. Cisneros ◽

Katie E. Davis ◽

Lindsay M. Dreiss ◽

...

Keyword(s):

Species Richness ◽

Elevation Gradient ◽

Biosphere Reserve ◽

Elevational Gradient ◽

Historical Biogeography ◽

Relative Importance ◽

Functional Biodiversity ◽

Elevational Gradients ◽

Evolutionary Mechanisms ◽

Peruvian Andes

ABSTRACTAimThe incorporation of functional and phylogenetic information is necessary to comprehensively characterize spatial patterns of biodiversity and to evaluate the relative importance of ecological and evolutionary mechanisms in molding such patterns. We evaluated the relative importance of mechanisms that shape passerine biodiversity along an extensive elevational gradient.LocationManu Biosphere Reserve in the Peruvian AndesTaxonSongbirds (order Passeriformes)MethodsWe quantified elevational gradients of species richness, phylogenetic biodiversity, and functional biodiversity for all passerines as well as separately for suboscines and oscines; determined if phylogenetic or functional biodiversity was consistent with random selection or if there was evidence of particular mechanisms dominating community assembly; and compared patterns for each dimension of biodiversity for the two suborders.ResultsFor all passerines and for suboscines, species richness decreased in a saturating fashion, phylogenetic biodiversity declined linearly, and functional biodiversity was stochastic along the elevation gradient. For oscines, species richness and phylogenetic biodiversity decreased linearly, and functional biodiversity decreased in a saturating fashion.Main conclusionsElevational gradients of biodiversity at Manu result from a combination of adaptations associated with radiations that occurred elsewhere (suboscines in Amazonian lowlands, oscines in colder climes of North America) and an in situ radiation in the Andes (tanagers). Our results suggest a combination of temperature-related physiological constraints and a reduction in functional redundancy associated with decreasing resource abundance at higher elevations molded the passerine assemblages along this elevational gradient. Explicit consideration of historical biogeography and conservatism of ancestral niches is necessary to comprehensively understand the mechanisms that mold gradients of biodiversity.

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High turn-over rates at the upper range limit and elevational source-sink dynamics in a widespread songbird

Scientific Reports ◽

10.1038/s41598-021-98100-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Martin U. Grüebler ◽

Johann von Hirschheydt ◽

Fränzi Korner-Nievergelt

Keyword(s):

Environmental Gradients ◽

Elevational Gradient ◽

High Elevation ◽

Range Limit ◽

Apparent Survival ◽

Breeding Sites ◽

Mobile Species ◽

Source Sink ◽

Turn Over ◽

High Elevations

AbstractThe formation of an upper distributional range limit for species breeding along mountain slopes is often based on environmental gradients resulting in changing demographic rates towards high elevations. However, we still lack an empirical understanding of how the interplay of demographic parameters forms the upper range limit in highly mobile species. Here, we study apparent survival and within-study area dispersal over a 700 m elevational gradient in barn swallows (Hirundo rustica) by using 15 years of capture-mark-recapture data. Annual apparent survival of adult breeding birds decreased while breeding dispersal probability of adult females, but not males increased towards the upper range limit. Individuals at high elevations dispersed to farms situated at elevations lower than would be expected by random dispersal. These results suggest higher turn-over rates of breeding individuals at high elevations, an elevational increase in immigration and thus, within-population source-sink dynamics between low and high elevations. The formation of the upper range limit therefore is based on preference for low-elevation breeding sites and immigration to high elevations. Thus, shifts of the upper range limit are not only affected by changes in the quality of high-elevation habitats but also by factors affecting the number of immigrants produced at low elevations.

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Shifts in the relative fitness contributions of fecundity and survival in variable and changing environments

Journal of Experimental Biology ◽

10.1242/jeb.228031 ◽

2021 ◽

Vol 224 (Suppl 1) ◽

pp. jeb228031

Author(s):

Lauren B. Buckley ◽

Sean D. Schoville ◽

Caroline M. Williams

Keyword(s):

Environmental Conditions ◽

Energy Use ◽

Environmental Gradients ◽

Relative Fitness ◽

Relative Importance ◽

Fitness Components ◽

Climate Variability And Change ◽

Short Term ◽

Climate Gradients ◽

Recent Climate

ABSTRACTOrganisms respond to shifts in climate means and variability via distinct mechanisms. Accounting for these differential responses and appropriately aggregating them is central to understanding and predicting responses to climate variability and change. Separately considering fitness components can clarify organismal responses: fecundity is primarily an integrated, additive response to chronic environmental conditions over time via mechanisms such as energy use and acquisition, whereas survival can be strongly influenced by short-term, extreme environmental conditions. In many systems, the relative importance of fecundity and survival constraints changes systematically along climate gradients, with fecundity constraints dominating at high latitudes or altitudes (i.e. leading range edges as climate warms), and survival constraints dominating at trailing range edges. Incorporating these systematic differences in models may improve predictions of responses to recent climate change over models that assume similar processes along environmental gradients. We explore how detecting and predicting shifts in fitness constraints can improve our ability to forecast responses to climate gradients and change.

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Phylogeography of two Andean frogs: Test of vicariance versus elevational gradient models of diversification

10.1101/819557 ◽

2019 ◽

Author(s):

Daria Koscinski ◽

Paul Handford ◽

Pablo L. Tubaro ◽

Peiwen Li ◽

Stephen C. Lougheed

Keyword(s):

Sequence Data ◽

Environmental Gradients ◽

Spatial Scales ◽

Elevational Gradient ◽

Northwestern Argentina ◽

Dna Sequence Data ◽

The Andes ◽

Common Causes ◽

History Of ◽

Historical Range

ABSTRACTThe tropical and subtropical Andes have among the highest levels of biodiversity in the world. Understanding the forces that underlie speciation and diversification in the Andes is a major focus of research. Here we tested two hypotheses of species origins in the Andes: 1. Vicariance mediated by orogenesis or shifting habitat distribution. 2. Parapatric diversification along elevational environmental gradients. We also sought insights on the factors that impacted the phylogeography of co-distributed taxa, and the influences of divergent species ecology on population genetic structure. We used phylogeographic and coalescent analyses of nuclear and mitochondrial DNA sequence data to compare genetic diversity and evolutionary history of two frog species: Pleurodema borellii (Family: Leiuperidae, 130 individuals; 20 sites), and Hypsiboas riojanus (Family: Hyllidae, 258 individuals; 23 sites) across their shared range in northwestern Argentina. The two showed concordant phylogeographic structuring, and our analyses support the vicariance model over the elevational gradient model. However, Pleurodema borellii exhibited markedly deeper temporal divergence (≥4 Ma) than H. riojanus (1-2 Ma). The three main mtDNA lineages of P. borellii were nearly allopatric and diverged between 4-10 Ma. At similar spatial scales, differentiation was less in the putatively more habitat-specialized H. riojanus than in the more generalist P. borellii. Similar allopatric distributions of major lineages for both species implies common causes of historical range fragmentation and vicariance. However, different divergence times among clades presumably reflect different demographic histories, permeability of different historical barriers at different times, and/or difference in life history attributes and sensitivities to historical environmental change. Our research enriches our understanding of the phylogeography of the Andes in northwestern Argentina.

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

Forests ◽

10.3390/f9090511 ◽

2018 ◽

Vol 9 (9) ◽

pp. 511 ◽

Cited By ~ 2

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.

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Fish assemblages in coastal lagoons in land-uplift succession: The relative importance of local and regional environmental gradients

Estuarine Coastal and Shelf Science ◽

10.1016/j.ecss.2008.10.021 ◽

2009 ◽

Vol 81 (2) ◽

pp. 247-256 ◽

Cited By ~ 28

Author(s):

Martin Snickars ◽

Alfred Sandström ◽

Antti Lappalainen ◽

Johanna Mattila ◽

Kajsa Rosqvist ◽

...

Keyword(s):

Fish Assemblages ◽

Environmental Gradients ◽

Coastal Lagoons ◽

Relative Importance ◽

Land Uplift

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Relative importance of environmental gradients and historical trawling effort in determining the composition and distribution of benthic macro-biota in a large inverse estuary

Fisheries Research ◽

10.1016/j.fishres.2010.11.003 ◽

2011 ◽

Vol 107 (1-3) ◽

pp. 184-195 ◽

Cited By ~ 8

Author(s):

David R. Currie ◽

Cameron D. Dixon ◽

Shane D. Roberts ◽

Graham E. Hooper ◽

Shirley J. Sorokin ◽

...

Keyword(s):

Environmental Gradients ◽

Relative Importance ◽

Inverse Estuary

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Describing macroecological patterns in microbes: Approaches for comparative analyses of operational taxonomic unit read number distribution with a case study of global oceanic bacteria

10.1101/778829 ◽

2019 ◽

Author(s):

Ryosuke Nakadai ◽

Yusuke Okazaki ◽

Shunsuke Matsuoka

Keyword(s):

Bacterial Communities ◽

High Throughput Sequencing ◽

Environmental Gradients ◽

Species Abundance ◽

Operational Taxonomic Unit ◽

Tree Communities ◽

Species Abundance Distributions ◽

Similarities And Differences ◽

Read Number ◽

Commonness And Rarity

AbstractDescribing the variation in commonness and rarity in a community is a fundamental method of evaluating biodiversity. Such patterns have been studied in the context of species abundance distributions (SADs) among macroscopic organisms in numerous communities. Recently, models for analyzing variation in local SAD shapes along environmental gradients have been constructed. The recent development of high-throughput sequencing enables evaluation of commonness and rarity in local communities of microbes using operational taxonomic unit (OTU) read number distributions (ORDs), which are conceptually similar to SADs. However, few studies have explored the variation in local microbial ORD shapes along environmental gradients. Therefore, the similarities and differences between SADs and ORDs are unclear, clouding any universal rules of global biodiversity patterns. We investigated the similarities and differences in ORD shapes vs. SADs, and how well environmental variables explain the variation in ORDs along latitudinal and depth gradients. Herein, we integrate ORDS into recent comparative analysis methods for SAD shape using datasets generated on the Tara Oceans expedition. About 56% of the variance in skewness of ORDs among global oceanic bacterial communities was explained with this method. Moreover, we confirmed that the parameter combination constraints of Weibull distributions were shared by ORDs of bacterial communities and SADs of tree communities, suggesting common long-term limitation processes such as adaptation and community persistence acting on current abundance variation. On the other hand, skewness was significantly greater for bacterial communities than tree communities, and many ecological predictions did not apply to bacterial communities, suggesting differences in the community assembly rules for microbes and macroscopic organisms. Approaches based on ORDs provide opportunities to quantify macroecological patterns of microbes under the same framework as macroscopic organisms.

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The effect of host community functional traits on plant disease risk varies along an elevational gradient

eLife ◽

10.7554/elife.67340 ◽

2021 ◽

Vol 10 ◽

Author(s):

Fletcher W Halliday ◽

Mikko Jalo ◽

Anna-Liisa Laine

Keyword(s):

Community Structure ◽

Disease Risk ◽

Environmental Gradients ◽

Elevational Gradient ◽

Host Community ◽

Interactive Effects ◽

Life History Strategies ◽

Herbaceous Plant ◽

Field Evidence ◽

Increasing Temperature

Quantifying the relative impact of environmental conditions and host community structure on disease is one of the greatest challenges of the 21st century, as both climate and biodiversity are changing at unprecedented rates. Both increasing temperature and shifting host communities towards more fast-paced life-history strategies are predicted to increase disease, yet their independent and interactive effects on disease in natural communities remains unknown. Here, we address this challenge by surveying foliar disease symptoms in 220, 0.5 meter-diameter herbaceous plant communities along a 1100-meter elevational gradient. We find that increasing temperature associated with lower elevation can increase disease by (1) relaxing constraints on parasite growth and reproduction, (2) determining which host species are present in a given location, and (3) strengthening the positive effect of host community pace-of-life on disease. These results provide the first field evidence, under natural conditions, that environmental gradients can alter how host community structure affects disease.

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