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opencc-zeroDec 2021View details →

Elevational niche-shift migration: Why the degree of elevational change matters for the ecology, evolution, and physiology of migratory birds to ornithology

Elevational migration can be defined as roundtrip seasonal movement that involves upward and downward shifts in elevation. These shifts incur physiological challenges that are proportional to the degree of elevational change. Larger shifts in elevation correspond to larger shifts in partial pressure of oxygen, air density, temperature, and UV exposure. Although most avian examples of elevational migration involve subtle shifts that would have minimal impacts on physiology, shifts of any magnitude have previously been considered under the broad umbrella of 'elevational migration'. Here, we consider extreme seasonal elevational movements (≥2000 m), sufficient to shift the elevational dimension of the eco-climatic niche. Migratory bird populations typically maintain inter-seasonal stability in the temperature, precipitation, and elevational aspects of their climatic niches, a tendency that likely reflects genetic physiological specialization on environmental conditions such as atmospheric pressure. A shift of ≥2000 m involves a ≥20% change in air density and oxygen partial pressure, sufficient to incur functionally impactful declines in arterial blood-oxygen saturation and require compensatory shifts in respiratory physiology. We refer to this phenomenon as elevational niche-shift migration (ENSM). In this review, we analyzed >4 million occurrence records to identify 105 populations, representing 92 bird species, that undergo complete or partial ENSM. We identified key ecological and evolutionary questions regarding causes and consequences of ENSM. Our synthesis reveals that ENSM has evolved independently in at least 29 avian families spanning 10 orders. Nonetheless, ENSM is rare relative to other forms of seasonal migration, consistent with the general tendency of seasonal niche conservatism by migratory species and evolutionarily conserved elevational range limits. For many migratory species and populations, within-species patterns of migratory connectivity are not sufficiently understood to determine ENSM status. ENSM is distinguished by its scale within the broader phenomenon of elevational migration. Critical examination of ENSM illustrates fundamental constraints on the ecology and evolution of migration systems, topographical influences on geographic patterns of migratory connectivity, and the remarkable metabolic flexibility of certain bird species that allows them to occupy disparate elevations across different seasons.

opencc-zeroDec 2013View details →

Data from: Rethinking niche evolution: experiments with natural communities of protozoa in pitcher plants

Classic niche theory predicts that competing species will evolve to use different resources and interact less, whereas recent niche-converge ideas predict that species evolve to use similar resources and interact more. Most data supporting niche evolution are based on observations of contemporary niche use, whereas experimental support is quite sparse. We followed the evolution of four species of Protozoa during succession in the water-filled leaves of the pitcher plant, Sarracenia purpurea, and found that evolution in multispecies systems follows a surprising pattern. Over several hundred generations, weak competitors evolved to be stronger while strong competitors evolved to become weaker, which does not conform to expectations of either niche divergence or convergence. Evolution in this system appears to occur in response to characteristics of a suite of several competitors in the community, rather than pairwise interactions. Ecologists may need to rethink the roles of competition and evolution in structuring communities.

opencc-zeroDec 2013View details →

Data from: Decoupled evolution of foliar freezing resistance, temperature-niche and morphological leaf traits in Chilean Myrceugenia

1. Phylogenetic conservatism of tolerance to freezing temperatures has been cited to explain the tendency of plant lineages to grow in similar climates. However there is little information about whether or not freezing resistance is conserved across phylogenies, and whether conservatism of physiological traits could explain conservatism of realized climatic niches. Here we compared the phylogenetical lability of realized climatic niche, foliar freezing resistance, and four morphological leaf traits that are generally considered adaptations to frost resistance in Chilean species of Myrceugenia, which grow in a wide range of habitats. 2. We estimated the predicted niche occupancy profiles with respect to minimum temperature (minT) of all species. We measured foliar freezing resistance (using chlorophyll fluorescence), leaf size, leaf mass per area (LMA), stomatal and trichome densities of ten individuals per species. Finally, we estimated phylogenetic signal and we performed independent contrast analyses among all variables. 3. We found that both foliar freezing resistance and minT were subject to a significant phylogenetic signal, but the former had a stronger signal. We also detected a significant but weak correlation between them (r=0.49, pone tail= 0.04). Morphological traits evolved independent of any phylogenetic effect. Synthesis. Our results show that freezing resistance evolved in association with temperature niche, but with some delay that could result from phylogenetic inertia. Our results also show that morphological leaf traits are more labile than realized climatic niche and frost tolerance and the former probably evolved associated to microhabitat preferences.

opencc-zeroDec 2011View details →

Data from: Biophysical modeling of the temporal niche: from first principles to the evolution of activity patterns

Most mammals can be characterized as nocturnal or diurnal. However infrequently, species may overcome evolutionary constraints and alter their activity patterns. We modeled the fundamental temporal niche of a diurnal desert rodent, the golden spiny mouse, Acomys russatus. This species can shift into nocturnal activity in the absence of its congener, the common spiny mouse, A. cahirinus, suggesting that it was competitively driven into diurnality, and that this shift in a small desert rodent may involve physiological costs. Therefore, we compared metabolic costs of diurnal vs. nocturnal activity using a biophysical model to evaluate the preferred temporal niche of this species. The model predicted that energy expenditure during foraging is almost always lower during the day except during mid-day in summer at the less sheltered microhabitat. We also found that a shift in summer to foraging in less sheltered microhabitats in response to predation pressure and food availability involves a significant physiological cost moderated by midday reduction in activity. Thus adaptation to diurnality may reflect the 'ghost of competition past'; Climate-driven diurnality is an alternative but less likely hypothesis. While climate is considered to play a major role in the physiology and evolution of mammals, this is the first study to model its effect on the evolution of activity patterns of mammals.

opencc-by-4.0Nov 2023View details →

Supplementary - Testing the Tropical Niche Conservatism Hypothesis: Climatic niche evolution of Escallonia Mutis ex L. F. (Escalloniaceae)

Supplementary material of the article Testing the Tropical Niche Conservatism Hypothesis: Climatic niche evolution of Escallonia Mutis ex L. F. (Escalloniaceae)

opennotspecifiedJun 2016View details →

Fig. 3 in Climatic niche evolution in the Andean genus Menonvillea (Cremolobeae: Brassicaceae)

Fig. 3 Maximum clade credibility species tree (MCCT) estimated from nuclear ribosomal ITS and three chloroplast DNA regions (trnL-F, trnHpsbA, rps16 intron) using the multispecies coalescent method implement- ed in *BEAST, uncorrelated log-normal relaxed clock model, and two

opennotspecifiedSep 2023View details →

Figure 2 in Niche evolution and diversification in Middle Eastern stream salamanders (Paradactylodon): vulnerability to future climate change

Figure 2. Recent (A: 1970-2000) and future (2081-2100) habitat suitability of Paradactylodon species based on the consensus model under optimistic (B: ssp126) and pessimistic (C: ssp585) scenarios.

opennotspecifiedSep 2023View details →

Figure 1 in Niche evolution and diversification in Middle Eastern stream salamanders (Paradactylodon): vulnerability to future climate change

Figure 1. Study area. The occurrence records of Paradactylodon species with different colors are shown on the map.

opennotspecifiedSep 2023View details →

Figure 3 in Niche evolution and diversification in Middle Eastern stream salamanders (Paradactylodon): vulnerability to future climate change

Figure 3. Panels (A-D) illustrate the niche overlap values between two species distribution ranges (see table 3), along the

Fig. 2 in Divergent evolution of mitogenomics in Cetartiodactyla niche adaptation

Fig. 2 The relative synonymous codon usage (RSCU) of Babyrousa babyrussa (a), Cephalorhynchus commersonii (b), Stenella clymene (c), and Stenella frontalis (d). Codon families are plotted on the X axis

Fig. 7 in Divergent evolution of mitogenomics in Cetartiodactyla niche adaptation

Fig. 7 Comparisons of ω values among 34 Cetartiodactyla species of different niches, based on 13 protein-coding genes (PCGs) and each PCG. CL, low-altitude; CM, marine; CH, high-altitude

Fig. 8 in Divergent evolution of mitogenomics in Cetartiodactyla niche adaptation

Fig. 8 Phylogenetic independent contrast analysis between different niches and root-to-tip ω values (Log10-transformed) of 13 PCGs dataset in 34 Cetartiodactyla species

Fig. 5 in Divergent evolution of mitogenomics in Cetartiodactyla niche adaptation

Fig. 5 Estimates of divergence time of Cetartiodactyla species with three fossil calibration points inferred from an analysis of 34 complete mitogenomes

Fig. 1 in Divergent evolution of mitogenomics in Cetartiodactyla niche adaptation

Fig. 1 Gene maps of mitogenome of Babyrousa babyrussa (a), Cephalorhynchus commersonii (b), Stenella clymene (c), and Stenella frontalis (d). The genes outside the circle are transcribed clockwise, while the genes inside are transcribed counterclockwise

Fig. 6 in Divergent evolution of mitogenomics in Cetartiodactyla niche adaptation

Fig. 6 Boxplot of molecular evolution rate (ω) of ND6 gene from 34 Cetartiodactyla species mitogenomes

opencc-zeroDec 2013View details →

Data from: Macroevolutionary consequences of profound climate change on niche evolution in marine mollusks over the past three million years

In order to predict the fate of biodiversity in a rapidly changing world, we must first understand how species adapt to new environmental conditions. The long-term evolutionary dynamics of species' physiological tolerances to differing climatic regimes remain obscure. Here, we unite palaeontological and neontological data to analyse whether species' environmental tolerances remain stable across 3 Myr of profound climatic changes using 10 phylogenetically, ecologically and developmentally diverse mollusc species from the Atlantic and Gulf Coastal Plains, USA. We additionally investigate whether these species' upper and lower thermal tolerances are constrained across this interval. We find that these species' environmental preferences are stable across the duration of their lifetimes, even when faced with significant environmental perturbations. The results suggest that species will respond to current and future warming either by altering distributions to track suitable habitat or, if the pace of change is too rapid, by going extinct. Our findings also support methods that project species' present-day environmental requirements to future climatic landscapes to assess conservation risks.

opencc-zeroDec 2015View details →

Data from: Including fossils in phylogenetic climate reconstructions: a deep time perspective on the climatic niche evolution and diversification of spiny lizards (Sceloporus)

Fossils and other paleontological information can improve phylogenetic comparative method estimates of phenotypic evolution and generate hypotheses related to species diversification. Here, we use fossil information to calibrate ancestral reconstructions of suitable climate for Sceloporus lizards in North America. Integrating data from the fossil record, general circulation models of paleoclimate during the Miocene, climate envelope modeling, and phylogenetic comparative methods provides a geographically and temporally explicit species distribution model of Sceloporus-suitable habitat through time. We provide evidence to support the historic biogeographic hypothesis of Sceloporus diversification in warm North American deserts and suggest a relatively recent Sceloporus invasion into Mexico around 6 Ma. We use a physiological model to map extinction risk. We suggest that the number of hours of restriction to a thermal refuge limited Sceloporus from inhabiting Mexico until the climate cooled enough to provide suitable habitat at approximately 6 Ma. If the future climate returns to the hotter climates of the past, Mexico, the place of highest modern Sceloporus richness, will no longer provide suitable habitats for Sceloporus to survive and reproduce.

opencc-zeroAug 2021View details →

Using niche centrality within the scope of the nearly neutral theory of evolution to predict genetic diversity in a tropical conifer species-pair

Aim: Estimating genetic diversity is key for understanging biogeographic and evolutionary processes. However, gathering genetic information is not feasible for all taxa or populations, particularly in the tropical regions. Identifying proxies for inferring such values has thus become essential. Here, we built on the niche centrality hypothesis (NCH; or central-abundance hypothesis) and the nearly neutral theory of evolution (NNT) to identify some of such proxies using a montane tropical conifer species-pair as model. The NCH predicts more genetic diversity under optimal ecological conditions, which should also allow for more efficient purifying selection, according to the NNT. Location: The Transmexican Volcanic Belt, central Mexico. Taxa: A fir species-pair endemic to central Mexico, Abies flinckii and A. religiosa. Methods: We estimated patterns of genetic diversity from nuclear SSRs (A, HE), and gene-coding sequences (πS, πN), together with the efficacy of purifying selection, measured as πN/πS. After testing for niche overlap, we used several geographic and ecological proxies (i.e. longitude, latitude, elevation, estimated area, and distance to the niche centroid in the present and in the LGM) to predict genetic diversity and πN/πS using general linear models. Results: Populations at the west of the Trans Mexican Volcanic Belt (TVB) had lower genetic diversity than populations in the east of this mountain chain. Both species had significant niche overlap. The principal predictors for neutral genetic diversity (HE, A and πS) were longitude and latitude, followed by the current distance to the niche centroid; the efficiency of purifying selection was mostly accounted for by the current distance to the niche centroid (which was also correlated to elevation). No correlation was observed between genetic diversity or πN/πS and current population area. Main conclusions: Historical and ecological factors have to be taken into account for explaining the amounts of genetic diversity in mountain tropical species. Following the NTT, populations closer to the niche centroid are more efficient at eliminating slightly deleterious mutations than marginal stands, independently of their size or geographical location (longitude). Expanding the central-abundance theory within the scope of the NTT might help reconciling conflicting views concerning the extent of its empirical support.

opennotspecifiedAug 2011View details →

Figure 2 in Body size estimation and evolution in metriorhynchid crocodylomorphs: implications for species diversification and niche partitioning

Figure 2. Evolutionary relationships of metriorhynchid genera based on the new phylogenetic analysis presented herein. Geological ranges are based on the taxonomic compendium in Young et al. (2010). Labelled nodes represent clades: (1) Metriorhynchidae; (2) Metriorhynchinae; (3) Geosaurinae; and (4) Geosaurini.