Journal articles: 'Latitudinal gradients'

1

Gaston, Kevin J. "Biodiversity - latitudinal gradients." Progress in Physical Geography: Earth and Environment 20, no. 4 (December 1996): 466–76. http://dx.doi.org/10.1177/030913339602000406.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Lyu, Lixin, Susanne Suvanto, Pekka Nöjd, Helena M. Henttonen, Harri Mäkinen, and Qi-Bin Zhang. "Tree growth and its climate signal along latitudinal and altitudinal gradients: comparison of tree rings between Finland and the Tibetan Plateau." Biogeosciences 14, no. 12 (June 23, 2017): 3083–95. http://dx.doi.org/10.5194/bg-14-3083-2017.

Full text

Abstract:

Abstract. Latitudinal and altitudinal gradients can be utilized to forecast the impact of climate change on forests. To improve the understanding of how these gradients impact forest dynamics, we tested two hypotheses: (1) the change of the tree growth–climate relationship is similar along both latitudinal and altitudinal gradients, and (2) the time periods during which climate affects growth the most occur later towards higher latitudes and altitudes. To address this, we utilized tree-ring data from a latitudinal gradient in Finland and from two altitudinal gradients on the Tibetan Plateau. We analysed the latitudinal and altitudinal growth patterns in tree rings and investigated the growth–climate relationship of trees by correlating ring-width index chronologies with climate variables, calculating with flexible time windows, and using daily-resolution climate data. High latitude and altitude plots showed higher correlations between tree-ring chronologies and growing season temperature. However, the effects of winter temperature showed contrasting patterns for the gradients. The timing of the highest correlation with temperatures during the growing season at southern sites was approximately 1 month ahead of that at northern sites in the latitudinal gradient. In one out of two altitudinal gradients, the timing for the strongest negative correlation with temperature at low-altitude sites was ahead of treeline sites during the growing season, possibly due to differences in moisture limitation. Mean values and the standard deviation of tree-ring width increased with increasing mean July temperatures on both types of gradients. Our results showed similarities of tree growth responses to increasing seasonal temperature between latitudinal and altitudinal gradients. However, differences in climate–growth relationships were also found between gradients due to differences in other factors such as moisture conditions. Changes in the timing of the most critical climate variables demonstrated the necessity for the use of daily-resolution climate data in environmental gradient studies.

APA, Harvard, Vancouver, ISO, and other styles

3

Marshall;, C. R., D. Schluter, and J. Weir. "Explaining Latitudinal Diversity Gradients." Science 317, no. 5837 (July 27, 2007): 451–53. http://dx.doi.org/10.1126/science.317.5837.451.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Pennell, Matthew W. "What Explains Latitudinal Diversity Gradients?" Trends in Ecology & Evolution 34, no. 5 (May 2019): 390–92. http://dx.doi.org/10.1016/j.tree.2019.02.011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Valentine, James W., David Jablonski, Andrew Z. Krug, and Kaustuv Roy. "Incumbency, diversity, and latitudinal gradients." Paleobiology 34, no. 2 (March 2008): 169–78. http://dx.doi.org/10.1666/0094-8373(2008)034[0169:idalg]2.0.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Pianka, Eric R. "Latitudinal gradients in species diversity." Trends in Ecology & Evolution 4, no. 8 (August 1989): 223. http://dx.doi.org/10.1016/0169-5347(89)90163-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Powell, Matthew G., and Douglas S. Glazier. "Asymmetric geographic range expansion explains the latitudinal diversity gradients of four major taxa of marine plankton." Paleobiology 43, no. 2 (February 6, 2017): 196–208. http://dx.doi.org/10.1017/pab.2016.38.

Full text

Abstract:

AbstractExtensive investigation of the close association between biological diversity and environmental temperature has not yet yielded a generally accepted, empirically validated mechanism to explain latitudinal gradients of species diversity, which occur in most taxa. Using the highly resolved late Cenozoic fossil records of four major taxa of marine plankton, we show that their gradients arise as a consequence of asymmetric geographic range expansion rather than latitudinal variation in diversification rate, as commonly believed. Neither per capita speciation nor extinction rates trend significantly with temperature or latitude for these marine plankton. Species of planktonic foraminifera and calcareous nannoplankton that originate in the temperate zone preferentially spread toward and arrive earlier in the tropics to produce a normal gradient with tropical diversity peaks; by contrast, temperate-zone originating species of diatoms and radiolarians preferentially spread toward and arrive earlier in polar regions to produce reversed gradients with high-latitude diversity peaks. Our results suggest that temperature affects latitudinal diversity gradients chiefly by its effect on species’ range limits rather than on probabilities of speciation and extinction. We show that this mechanism also appears to operate in various multicellular taxa, thus providing a widely applicable explanation for the origin of latitudinal diversity gradients.

APA, Harvard, Vancouver, ISO, and other styles

8

Araújo, Márcio S., and Raul Costa-Pereira. "Latitudinal gradients in intraspecific ecological diversity." Biology Letters 9, no. 6 (December 23, 2013): 20130778. http://dx.doi.org/10.1098/rsbl.2013.0778.

Full text

Abstract:

The increase in the number of species with decreasing latitude is a striking pattern of global biodiversity. An important feature of studies of this pattern up to now has been the focus on species as the fundamental unit of interest, neglecting potential within-species ecological diversity. Here, we took a new perspective on this topic by measuring the degree to which individuals within populations differ in niche attributes across a latitudinal gradient (range: 54.01° S to 69.12° N). We show that 156 populations of 76 species across a wide range of vertebrate and invertebrate animal taxa contain more ecologically diverse assemblages of individuals towards lower latitudes. Our results add a new level of complexity to our understanding of global patterns of biodiversity and suggest the possibility that niche variation is partly responsible for the latitudinal gradients of species diversity.

APA, Harvard, Vancouver, ISO, and other styles

9

Pero, Edgardo J. I., Paola A. Rueda Martín, and María C. Reynaga. "Species and genus richness and assemblage composition of stream caddisflies (Insecta: Trichoptera) vary with latitude in mountain rainforest of Argentina." Marine and Freshwater Research 70, no. 5 (2019): 687. http://dx.doi.org/10.1071/mf18209.

Full text

Abstract:

Evidence found in results of studies of latitudinal gradients of benthic macroinvertebrate diversity is variable. This study analysed how species and genus richness and the composition of caddisfly assemblages (Insecta: Trichoptera) vary in Argentinean mountain forest through a latitudinal gradient from 22 to 28°S. Qualitative and quantitative data from 20 stream sites were compared. Assemblage richness and composition were analysed by comparing linear regressions, rank–abundance (RA) curves and non-metric multidimensional scaling (nMDS). Taxonomic richness increased from high to low latitude. RA curves showed changes in assemblage composition and structure across the latitudinal gradient. The nMDS revealed that the composition of the assemblages also changed along the latitudinal gradient. The patterns are similar to those observed in plants and vertebrates from the study region. The results are of particular note because a latitudinal gradient of aquatic insect diversity has rarely been observed in a narrow range.

APA, Harvard, Vancouver, ISO, and other styles

10

Gratton, Paolo, Silvio Marta, Gaëlle Bocksberger, Marten Winter, Petr Keil, Emiliano Trucchi, and Hjalmar Kühl. "Which Latitudinal Gradients for Genetic Diversity?" Trends in Ecology & Evolution 32, no. 10 (October 2017): 724–26. http://dx.doi.org/10.1016/j.tree.2017.07.007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Rind, D. "Latitudinal temperature gradients and climate change." Journal of Geophysical Research: Atmospheres 103, no. D6 (March 1, 1998): 5943–71. http://dx.doi.org/10.1029/97jd03649.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Tomašových, Adam, Jonathan D. Kennedy, Tristan J. Betzner, Nicole Bitler Kuehnle, Stewart Edie, Sora Kim, K. Supriya, et al. "Unifying latitudinal gradients in range size and richness across marine and terrestrial systems." Proceedings of the Royal Society B: Biological Sciences 283, no. 1830 (May 11, 2016): 20153027. http://dx.doi.org/10.1098/rspb.2015.3027.

Full text

Abstract:

Many marine and terrestrial clades show similar latitudinal gradients in species richness, but opposite gradients in range size—on land, ranges are the smallest in the tropics, whereas in the sea, ranges are the largest in the tropics. Therefore, richness gradients in marine and terrestrial systems do not arise from a shared latitudinal arrangement of species range sizes. Comparing terrestrial birds and marine bivalves, we find that gradients in range size are concordant at the level of genera. Here, both groups show a nested pattern in which narrow-ranging genera are confined to the tropics and broad-ranging genera extend across much of the gradient. We find that (i) genus range size and its variation with latitude is closely associated with per-genus species richness and (ii) broad-ranging genera contain more species both within and outside of the tropics when compared with tropical- or temperate-only genera. Within-genus species diversification thus promotes genus expansion to novel latitudes. Despite underlying differences in the species range-size gradients, species-rich genera are more likely to produce a descendant that extends its range relative to the ancestor's range. These results unify species richness gradients with those of genera, implying that birds and bivalves share similar latitudinal dynamics in net species diversification.

APA, Harvard, Vancouver, ISO, and other styles

13

Webb, Gregory E., William J. Sando, and Anne Raymond. "Mississippian coral latitudinal diversity gradients (western interior United States): Testing the limits of high resolution diversity data." Journal of Paleontology 71, no. 5 (September 1997): 780–91. http://dx.doi.org/10.1017/s0022336000035733.

Full text

Abstract:

Analysis of high resolution diversity data for Mississippian corals in the western interior United States yielded mild latitudinal diversity gradients despite the small geographic area covered by samples and a large influence on diversity patterns by geographic sampling intensity (sample bias). Three competing plate tectonic reconstructions were tested using the diversity patterns. Although none could be forcefully rejected, one reconstruction proved less consistent with diversity patterns than the other two and additional coral diversity data from farther north in Canada would better discriminate the two equivalent reconstructions.Despite the relatively high sampling intensity represented by the analyzed database, diversity patterns were greatly affected by sample abundance and distribution. Hence, some effort at recognizing and accounting for sample bias should be undertaken in any study of latitudinal diversity gradients. Small-scale geographic lumping of sample localities had only small effects on geographic diversity patterns. However, large-scale (e.g., regional) geographic lumping of diversity data may not yield latitudinally sensitive diversity patterns. Temporal changes in coral diversity in this region reflect changes in eustacy, local tectonism, and terrigenous sediment flux, far more than they do shifting latitude. Highest regional diversity occurred during the interval when the studied region occupied the highest latitude. Therefore, diversity data from different regions may not be comparable, in terms of latitudinal inference. Small-scale stratigraphic lumping of the data caused a nearly complete loss of the latitudinal diversity patterns apparent prior to lumping. Hence, the narrowest possible stratigraphic resolution should be maintained in analyzing latitudinal diversity gradients.

APA, Harvard, Vancouver, ISO, and other styles

14

Crame, J. Alistair. "Evolution of taxonomic diversity gradients in the marine realm: a comparison of Late Jurassic and Recent bivalve faunas." Paleobiology 28, no. 2 (2002): 184–207. http://dx.doi.org/10.1666/0094-8373(2002)028<0184:eotdgi>2.0.co;2.

Full text

Abstract:

We still have much to learn about the evolution of taxonomic diversity gradients through geologic time. For example, have latitudinal gradients always been as steep as they are now, or is this a phenomenon linked to some form of Cenozoic global climatic differentiation? The fossil record offers potential to address this sort of problem, and this study reconstructs latitudinal diversity gradients for the last (Tithonian) stage of the Jurassic period using marine bivalves. At this time of relative global warmth, bivalves were cosmopolitan in their distribution and the commonest element within macrobenthic assemblages.Analysis of 31 regional bivalve faunas demonstrates that Tithonian latitudinal gradients were present in both hemispheres, though on a much smaller magnitude than today. The record of the Northern Hemisphere gradient is more complete and shows a steep fall in values at the tropical/temperate boundary; the Southern Hemisphere gradient exhibits a more regular decline in diversity with increasing latitude.Tithonian latitudinal gradients were underpinned by a tropical bivalve fauna that comprises almost equal numbers of epifaunal and infaunal taxa. The epifaunal component was dominated by three pteriomorph families, the Pectinidae, Limidae and Ostreidae, that may be regarded as a long-term component of tropical bivalve diversity. Of the mixture of older and newer “heteroconch” families that formed the bulk of the infaunal component, the latter radiated spectacularly through the Late Cretaceous and Cenozoic to dominate tropical bivalve faunas at the present day. This pulse of heteroconch diversification, which was a major cause of the steepening of the bivalve latitudinal gradient, provides important evidence that rates of speciation may be negatively correlated with latitude.Nevertheless, we cannot exclude the possibility that elevated extinction rates in the highest latitudes also contributed to the marked steepening of bivalve latitudinal gradients over the last 150 Myr. Rates of extinction within epifaunal bivalve taxa appear to have been higher in these regions through the Cretaceous period, but this was largely before any significant global climatic deterioration. Infaunal bivalve clades have had differential success over this time period in the polar regions. Whereas, in comparison with the Tropics, heteroconchs are very much reduced in numbers today, the anomalodesmatans are much better represented, and the protobranchs have positively thrived. We are beginning to appreciate that low temperature per se may not be a primary cause of elevated rates of extinction. Food supply may be an equally important control on both rates of speciation and extinction; those bivalves that have been able to adapt to the extreme seasonality of food supply have flourished in the polar regions.

APA, Harvard, Vancouver, ISO, and other styles

15

Prata, Eduardo Magalhães Borges, Aloysio De Pádua Teixeira, Carlos Alfredo Joly, and Marco Antonio Assis. "The role of climate on floristic composition in a latitudinal gradient in the Brazilian Atlantic Forest." Plant Ecology and Evolution 151, no. 3 (November 28, 2018): 303–13. http://dx.doi.org/10.5091/plecevo.2018.1407.

Full text

Abstract:

Background and aims – Latitudinal gradients have an important influence on species distribution reflecting the effects of environmental factors such as temperature, rainfall, soil, and geographical distance. In the southeastern Brazilian Atlantic Forest, the role of climatic variables in the floristic composition is better known for altitudinal gradients of the Serra do Mar Mountains rather than for the latitudinal gradient. Here, we investigated the effects of mean annual temperature and rainfall on tree species distribution and composition in a latitudinal gradient in the Atlantic forest.Methods – We calculated each species frequency of occurrence and the latitudinal range. We used multivariate analyses (direct ordination, Hierarchical Clustering followed by Indicator Species analysis and NMDS) to investigate variation in floristic composition, and regression analyses to evaluate mean annual temperatures and rainfall effects on tree species composition along the latitudinal gradient (21°S to 28°S).Key results – A total of 789 species were registered, of which a majority (646 species) were present in less than 20% of the sampled areas, and only four species (0.5%) were present in more than 80% of the sampled areas. Only ten species (1.3%) reached the maximum latitudinal range (~6°). We found a strong correlation between variation in floristic composition and the spatial position in the latitudinal gradient. The cluster analyses detected two main floristic groups, one composed by the forests from Rio de Janeiro (21°S to 23°S) and the second by the forests from São Paulo, Paraná and Santa Catarina States (23°S to 28°S). The multiple regression analysis revealed a strong effect of the climatic variables on the variation of the floristic composition along the latitudinal gradient (r2 = 0.81, P < 0.001), where 62.82% of the variation were explained by mean annual temperature, 8.27% by annual rainfall and 10.45% by both variables together.Conclusions – The restricted distribution of most species may be explained by variations in mean annual temperature and annual rainfall along the latitudinal gradient. For instance, the decreasing mean annual temperature along the coast and the occurrence of frosts at higher latitudes may limit the southward distribution of some species while the lower annual rainfall (with marked seasonality) in the north of the gradient may limit the northward distribution of other species. Although mean annual temperature explained most of the variation in species composition along the latitudinal gradient, the abrupt variation in annual rainfall may explain the high floristic dissimilarity detected in the north of the gradient.

APA, Harvard, Vancouver, ISO, and other styles

16

Poulin, Robert. "Functional biogeography of parasite traits: hypotheses and evidence." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1837 (September 20, 2021): 20200365. http://dx.doi.org/10.1098/rstb.2020.0365.

Full text

Abstract:

Functional biogeography, or the study of trait-based distributional patterns, not only complements our understanding of spatial patterns in biodiversity, but also sheds light on the underlying processes generating them. In parallel with the well-studied latitudinal diversity gradient, decades-old ecogeographical rules also postulate latitudinal variation in species traits. Notably, species in the tropics are predicted to have smaller body sizes (Bergmann's rule), narrower niches (MacArthur's rule) and smaller geographical ranges (Rapoport's rule) than their counterparts at higher latitudes. Although originally proposed for free-living organisms, these rules have been extended to parasitic organisms as well. In this review, I discuss the mechanistic hypotheses most likely to explain latitudinal gradients in parasite traits, and assess the empirical evidence obtained from comparative studies testing the above three rules as well as latitudinal gradients in other parasite traits. Overall, there is only weak empirical support for latitudinal gradients in any parasite trait, with little consistency among comparative analyses. The most parsimonious explanation for the existence of geographical patterns in parasite traits is that they are primarily host-driven, i.e. ecological traits of parasites track those of their hosts, with a direct influence of bioclimatic factors playing a secondary role. Thus, geographical patterns in parasite traits probably emerge as epiphenomena of parallel patterns in their hosts. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.

APA, Harvard, Vancouver, ISO, and other styles

17

Baumann, Hannes, and David O. Conover. "Adaptation to climate change: contrasting patterns of thermal-reaction-norm evolution in Pacific versus Atlantic silversides." Proceedings of the Royal Society B: Biological Sciences 278, no. 1716 (January 5, 2011): 2265–73. http://dx.doi.org/10.1098/rspb.2010.2479.

Full text

Abstract:

How organisms may adapt to rising global temperatures is uncertain, but concepts can emerge from studying adaptive physiological trait variations across existing spatial climate gradients. Many ectotherms, particularly fish, have evolved increasing genetic growth capacities with latitude (i.e. countergradient variation (CnGV) in growth), which are thought to be an adaptation primarily to strong gradients in seasonality. In contrast, evolutionary responses to gradients in mean temperature are often assumed to involve an alternative mode, ‘thermal adaptation’. We measured thermal growth reaction norms in Pacific silverside populations ( Atherinops affinis ) occurring across a weak latitudinal temperature gradient with invariant seasonality along the North American Pacific coast. Instead of thermal adaptation, we found novel evidence for CnGV in growth, suggesting that CnGV is a ubiquitous mode of reaction-norm evolution in ectotherms even in response to weak spatial and, by inference, temporal climate gradients. A novel, large-scale comparison between ecologically equivalent Pacific versus Atlantic silversides ( Menidia menidia ) revealed how closely growth CnGV patterns reflect their respective climate gradients. While steep growth reaction norms and increasing growth plasticity with latitude in M. menidia mimicked the strong, highly seasonal Atlantic coastal gradient, shallow reaction norms and much smaller, latitude-independent growth plasticity in A. affinis resembled the weak Pacific latitudinal temperature gradient.

APA, Harvard, Vancouver, ISO, and other styles

18

Fraser, Danielle. "Can latitudinal richness gradients be measured in the terrestrial fossil record?" Paleobiology 43, no. 3 (March 9, 2017): 479–94. http://dx.doi.org/10.1017/pab.2017.2.

Full text

Abstract:

AbstractStudying the deep-time origins of macroecological phenomena can help us to understand their long-term drivers. Given the considerable spatiotemporal bias of the terrestrial fossil record, it behooves us to understand how much biological information is lost. The aim of this study is to establish whether latitudinal diversity gradients are detectable in a biased terrestrial fossil record. I develop a simulated fossilization approach, weighting the probability of terrestrial mammal species appearing in the fossil record based on body size and geographic-range size; larger species with larger range sizes are more likely to enter the fossil record. I create simulated fossil localities from the modern North American mammal record. I vary the percentage of species successfully fossilized and estimate the magnitude of the latitudinal diversity gradient (slope of the richness gradient and degree of species turnover). I find that estimates of the latitudinal diversity gradient are sensitive to the loss of species with small body size and geographic-range sizes. In some cases, simulated fossil-record bias completely obliterates evidence of declining richness with latitude, a phenomenon that is not ameliorated by the application of nonparametric richness estimation. However, if the rate of preservation is medium (50% of species) to high (75% of species), the magnitude of the latitudinal diversity gradient can be reliably estimated. Similarly, changes in the diversity gradient estimates are largely explained by differences in the diversity–climate relationship among iterations, suggesting that these relationships may be measurable in the fossil record.

APA, Harvard, Vancouver, ISO, and other styles

19

Koleff, Patricia, Jack J. Lennon, and Kevin J. Gaston. "Are there latitudinal gradients in species turnover?" Global Ecology and Biogeography 12, no. 6 (October 17, 2003): 483–98. http://dx.doi.org/10.1046/j.1466-822x.2003.00056.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Greenwood, David R., and Scott L. Wing. "Eocene continental climates and latitudinal temperature gradients." Geology 23, no. 11 (1995): 1044. http://dx.doi.org/10.1130/0091-7613(1995)023<1044:eccalt>2.3.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Mills, Alexander M. "Latitudinal gradients of biologically useful semi-darkness." Ecography 31, no. 5 (October 2008): 578–82. http://dx.doi.org/10.1111/j.0906-7590.2008.05346.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Van de Vliert, Evert, and Paul AM Van Lange. "Latitudinal gradients as scientific tools for psychologists." Current Opinion in Psychology 32 (April 2020): 43–46. http://dx.doi.org/10.1016/j.copsyc.2019.06.018.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Van de Vliert, Evert, and Paul A. M. Van Lange. "Latitudinal Psychology: An Ecological Perspective on Creativity, Aggression, Happiness, and Beyond." Perspectives on Psychological Science 14, no. 5 (August 21, 2019): 860–84. http://dx.doi.org/10.1177/1745691619858067.

Full text

Abstract:

Are there systematic trends around the world in levels of creativity, aggressiveness, life satisfaction, individualism, trust, and suicidality? This article suggests a new field, latitudinal psychology, that delineates differences in such culturally shared features along northern and southern rather than eastern and western locations. In addition to geographical, ecological, and other explanations, we offer three metric foundations of latitudinal variations: replicability (latitudinal gradient repeatability across hemispheres), reversibility (north-south gradient reversal near the equator), and gradient strength (degree of replicability and reversibility). We show that aggressiveness decreases whereas creativity, life satisfaction, and individualism increase as one moves closer to either the North or South Pole. We also discuss the replicability, reversibility, and gradient strength of (a) temperatures and rainfall as remote predictors and (b) pathogen prevalence, national wealth, population density, and income inequality as more proximate predictors of latitudinal gradients in human functioning. Preliminary analyses suggest that cultural and psychological diversity often need to be partially understood in terms of latitudinal variations in integrated exposure to climate-induced demands and wealth-based resources. We conclude with broader implications, emphasizing the importance of north-south replications in samples that are not from Western, educated, industrialized, rich, and democratic (WEIRD) societies.

APA, Harvard, Vancouver, ISO, and other styles

24

Morales-Castilla, Ignacio, and Raúl García-Valdés. "Reverse latitudinal diversity gradients, exceptions that prove the rule?" Ecosistemas 23, no. 1 (April 11, 2014): 4–12. http://dx.doi.org/10.7818/ecos.2014.23-1.02.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Bartels, Paul J., Diego Fontaneto, Milena Roszkowska, Diane R. Nelson, and Łukasz Kaczmarek. "Latitudinal gradients in body size in marine tardigrades." Zoological Journal of the Linnean Society 188, no. 3 (November 25, 2019): 820–38. http://dx.doi.org/10.1093/zoolinnean/zlz080.

Full text

Abstract:

Abstract Homeotherms and many poikilotherms display a positive relationship between body size and latitude, but this has rarely been investigated in microscopic animals. We analysed all published records of marine Tardigrada to address whether microscopic marine invertebrates have similar ecogeographical patterns to macroscopic animals. The data were analysed using spatially explicit generalized least squares models and linear models. We looked for latitudinal patterns in body size and species richness, testing for sampling bias and phylogenetic constraints. No latitudinal pattern was detected for species richness, and sampling bias was the strongest correlate of species richness. A hump-shaped increase in median body size with latitude was found, and the effect remained significant for the Northern Hemisphere but not for the Southern. The most significant effect supporting the latitudinal gradient was on minimum body size, with smaller species disappearing at higher latitudes. Our results suggest that biogeographical signals were observed for body size, albeit difficult to detect in poorly studied groups because of swamping from biased sampling effort and from low sample size. We did not find a significant correlation with the latitudinal pattern of body size and ecologically relevant net primary productivity.

APA, Harvard, Vancouver, ISO, and other styles

26

Hillebrand, H. "Strength, slope and variability of marine latitudinal gradients." Marine Ecology Progress Series 273 (2004): 251–67. http://dx.doi.org/10.3354/meps273251.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Chaudhary, Chhaya, Hanieh Saeedi, and Mark J. Costello. "Bimodality of Latitudinal Gradients in Marine Species Richness." Trends in Ecology & Evolution 31, no. 9 (September 2016): 670–76. http://dx.doi.org/10.1016/j.tree.2016.06.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Escarguel, G., A. Brayard, and H. Bucher. "Evolutionary rates do not drive latitudinal diversity gradients." Journal of Zoological Systematics and Evolutionary Research 46, no. 1 (January 10, 2008): 82–86. http://dx.doi.org/10.1111/j.1439-0469.2007.00443.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Manly. "Testing for latitudinal and other body-size gradients." Ecology Letters 1, no. 2 (September 1998): 104–11. http://dx.doi.org/10.1046/j.1461-0248.1998.00002.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Roy, K., D. Jablonski, J. W. Valentine, and G. Rosenberg. "Marine latitudinal diversity gradients: Tests of causal hypotheses." Proceedings of the National Academy of Sciences 95, no. 7 (March 31, 1998): 3699–702. http://dx.doi.org/10.1073/pnas.95.7.3699.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Qian, Hong, Shengbin Chen, Lingfeng Mao, and Zhiyun Ouyang. "Drivers of β-diversity along latitudinal gradients revisited." Global Ecology and Biogeography 22, no. 6 (December 20, 2012): 659–70. http://dx.doi.org/10.1111/geb.12020.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Harper, Elizabeth M., and Lloyd S. Peck. "Latitudinal and depth gradients in marine predation pressure." Global Ecology and Biogeography 25, no. 6 (April 13, 2016): 670–78. http://dx.doi.org/10.1111/geb.12444.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Jardine, Phillip E., Guy J. Harrington, Jocelyn A. Sessa, and Jiřina Dašková. "Drivers and constraints on floral latitudinal diversification gradients." Journal of Biogeography 45, no. 6 (March 23, 2018): 1408–19. http://dx.doi.org/10.1111/jbi.13216.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Hall, D. L., J. E. Humble, and M. L. Duldig. "Radial and Latitudinal Gradients in Galactic Cosmic Rays." Publications of the Astronomical Society of Australia 11, no. 2 (August 1994): 170–74. http://dx.doi.org/10.1017/s1323358000019846.

Full text

Abstract:

AbstractWe have deduced the yearly averaged value of the solar diurnal variation as observed by a surface muon telescope and three underground muon telescopes over the years 1957 to 1985. This has allowed us to examine the temporal variation in both the latitudinal gradient Gz and the product of the parallel mean free path and the radial gradient of galactic cosmic rays during three consecutive solar cycles. The median rigidities of the primary particles being detected by the telescopes are 50 GV in the case of the surface muon telescope and greater than 150 GV in the case of the underground muon telescopes. We have compared our results with those of a similar study made from observations of the solar diurnal variation by neutron monitors and an ion chamber, which have median rigidities of response between 17 and 70 GV (Bieber and Chen 1991a). The product has a solar magnetic cycle dependence and our values are lower than those observed by neutron monitors, in agreement with the Bieber and Chen observation that reverses after a solar magnetic field reversal, in accordance with drift theories.

APA, Harvard, Vancouver, ISO, and other styles

35

Nicholson, David B., Patricia A. Holroyd, Paul Valdes, and Paul M. Barrett. "Latitudinal diversity gradients in Mesozoic non-marine turtles." Royal Society Open Science 3, no. 11 (November 2016): 160581. http://dx.doi.org/10.1098/rsos.160581.

Full text

Abstract:

The latitudinal biodiversity gradient (LBG)—the pattern of increasing taxonomic richness with decreasing latitude—is prevalent in the structure of the modern biota. However, some freshwater taxa show peak richness at mid-latitudes; for example, extant Testudines (turtles, terrapins and tortoises) exhibit their greatest diversity at 25° N, a pattern sometimes attributed to recent bursts of climatically mediated species diversification. Here, we test whether this pattern also characterizes the Mesozoic distribution of turtles, to determine whether it was established during either their initial diversification or as a more modern phenomenon. Using global occurrence data for non-marine testudinate genera, we find that subsampled richness peaks at palaeolatitudes of 15–30° N in the Jurassic, 30–45° N through the Cretaceous to the Campanian, and from 30° to 60° N in the Maastrichtian. The absence of a significant diversity peak in southern latitudes is consistent with results from climatic models and turtle niche modelling that demonstrate a dearth of suitable turtle habitat in Gondwana during the Jurassic and Late Cretaceous. Our analyses confirm that the modern testudinate LBG has a deep-time origin and further demonstrate that LBGs are not always expressed as a smooth, equator-to-pole distribution.

APA, Harvard, Vancouver, ISO, and other styles

36

El-Borie, M. A., A. A. Darwish, and A. A. Bishara. "Long-term behavior of latitudinal cosmic-ray gradients." Solar Physics 167, no. 1-2 (August 1996): 395–407. http://dx.doi.org/10.1007/bf00146348.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Nunn, Charles L., Sonia M. Altizer, Wes Sechrest, and Andrew A. Cunningham. "Latitudinal gradients of parasite species richness in primates." Diversity and Distributions 11, no. 3 (April 28, 2005): 249–56. http://dx.doi.org/10.1111/j.1366-9516.2005.00160.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

GAULD, IAN D. "Latitudinal gradients in ichneumonid species-richness in Australia." Ecological Entomology 11, no. 2 (May 1986): 155–61. http://dx.doi.org/10.1111/j.1365-2311.1986.tb00290.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Harcourt, A. H., and B. M. Schreier. "Diversity, Body Mass, and Latitudinal Gradients in Primates." International Journal of Primatology 30, no. 2 (February 10, 2009): 283–300. http://dx.doi.org/10.1007/s10764-009-9342-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Humphries, Ruhi S., Melita D. Keywood, Sean Gribben, Ian M. McRobert, Jason P. Ward, Paul Selleck, Sally Taylor, et al. "Southern Ocean latitudinal gradients of cloud condensation nuclei." Atmospheric Chemistry and Physics 21, no. 16 (August 30, 2021): 12757–82. http://dx.doi.org/10.5194/acp-21-12757-2021.

Full text

Abstract:

Abstract. The Southern Ocean region is one of the most pristine in the world and serves as an important proxy for the pre-industrial atmosphere. Improving our understanding of the natural processes in this region is likely to result in the largest reductions in the uncertainty of climate and earth system models. While remoteness from anthropogenic and continental sources is responsible for its clean atmosphere, this also results in the dearth of atmospheric observations in the region. Here we present a statistical summary of the latitudinal gradient of aerosol (condensation nuclei larger than 10 nm, CN10) and cloud condensation nuclei (CCN at various supersaturations) concentrations obtained from five voyages spanning the Southern Ocean between Australia and Antarctica from late spring to early autumn (October to March) of the 2017/18 austral seasons. Three main regions of influence were identified: the northern sector (40–45∘ S), where continental and anthropogenic sources coexisted with background marine aerosol populations; the mid-latitude sector (45–65∘ S), where the aerosol populations reflected a mixture of biogenic and sea-salt aerosol; and the southern sector (65–70∘ S), south of the atmospheric polar front, where sea-salt aerosol concentrations were greatly reduced and aerosol populations were primarily biologically derived sulfur species with a significant history in the Antarctic free troposphere. The northern sector showed the highest number concentrations with median (25th to 75th percentiles) CN10 and CCN0.5 concentrations of 681 (388–839) cm−3 and 322 (105–443) cm−3, respectively. Concentrations in the mid-latitudes were typically around 350 cm−3 and 160 cm−3 for CN10 and CCN0.5, respectively. In the southern sector, concentrations rose markedly, reaching 447 (298–446) cm−3 and 232 (186–271) cm−3 for CN10 and CCN0.5, respectively. The aerosol composition in this sector was marked by a distinct drop in sea salt and increase in both sulfate fraction and absolute concentrations, resulting in a substantially higher CCN0.5/CN10 activation ratio of 0.8 compared to around 0.4 for mid-latitudes. Long-term measurements at land-based research stations surrounding the Southern Ocean were found to be good representations at their respective latitudes; however this study highlighted the need for more long-term measurements in the region. CCN observations at Cape Grim (40∘39′ S) corresponded with CCN measurements from northern and mid-latitude sectors, while CN10 observations only corresponded with observations from the northern sector. Measurements from a simultaneous 2-year campaign at Macquarie Island (54∘30′ S) were found to represent all aerosol species well. The southernmost latitudes differed significantly from both of these stations, and previous work suggests that Antarctic stations on the East Antarctic coastline do not represent the East Antarctic sea-ice latitudes well. Further measurements are needed to capture the long-term, seasonal and longitudinal variability in aerosol processes across the Southern Ocean.

APA, Harvard, Vancouver, ISO, and other styles

41

Stevens, Richard D. "Relative effects of time for speciation and tropical niche conservatism on the latitudinal diversity gradient of phyllostomid bats." Proceedings of the Royal Society B: Biological Sciences 278, no. 1717 (January 5, 2011): 2528–36. http://dx.doi.org/10.1098/rspb.2010.2341.

Full text

Abstract:

Determinants of contemporary patterns of diversity, particularly those spanning extensive latitudinal gradients, are some of the most intensely debated issues in ecology. Recently, focus has shifted from a contemporary environmental perspective to a historical one in an attempt to better understand the construction of latitudinal gradients. Although the vast majority of research on historical mechanisms has focused on tropical niche conservatism (TNC), other historical scenarios could produce similar latitudinal gradients. Herein, I formalize predictions to distinguish between two such historical processes—namely time for speciation (TFS) and TNC—and test relative support based on diversity gradients of New World bats. TFS and TNC are distinctly spatial and environmental mechanisms, respectively. Nonetheless, because of the way that environmental characteristics vary spatially, these two mechanisms are hard to distinguish. Evidence provided herein suggests that TNC has had a more important effect than TFS in determining diversity gradients of New World bats. Indeed, relative effects of different historical mechanisms, as well as relative effects of historical and contemporary environmental determinants, are probably context-dependent. Future research should move away from attempting to identify the mechanism with primacy and instead attempt to understand the particular contexts in which different mechanisms have greater influence on diversity gradients.

APA, Harvard, Vancouver, ISO, and other styles

42

Orcutt, John D., and Samantha S. B. Hopkins. "Latitudinal body-mass trends in Oligo-Miocene mammals." Paleobiology 42, no. 4 (May 3, 2016): 643–58. http://dx.doi.org/10.1017/pab.2016.13.

Full text

Abstract:

AbstractPaleecological data allow not only the study of trends along deep-time chronological transects but can also be used to reconstruct ecological gradients through time, which can help identify causal factors that may be strongly correlated in modern ecosystems. We have applied such an analysis to Bergmann’s rule, which posits a causal relationship between temperature and body size in mammals. Bergmann’s rule predicts that latitudinal gradients should exist during any interval of time, with larger taxa toward the poles and smaller taxa toward the equator. It also predicts that the strength of these gradients should vary with time, becoming weaker during warmer periods and stronger during colder conditions. We tested these predictions by reconstructing body-mass trends within canid and equid genera at different intervals of the Oligo-Miocene along the West Coast of North America. To allow for comparisons with modern taxa, body mass was reconstructed along the same transect for modernCanisandOdocoileus. Of the 17 fossil genera analyzed, only two showed the expected positive relationship with latitude, nor was there consistent evidence for a relationship between paleotemperature and body mass. Likewise, the strength of body-size gradients does not change predictably with climate through time. The evidence for clear gradients is ambiguous even in the modern genera analyzed. These results suggest that, counter to Bergmann’s rule, temperature alone is not a primary driver of body size and underscore the importance of regional-scale paleoecological analyses in identifying such drivers.

APA, Harvard, Vancouver, ISO, and other styles

43

Huang, Zhang, Fu, and Zhang. "Environmental Filtering Drives Local Soil Fungal beta Diversity More than Dispersal Limitation in Six Forest Types along a Latitudinal Gradient in Eastern China." Forests 10, no. 10 (October 2, 2019): 863. http://dx.doi.org/10.3390/f10100863.

Full text

Abstract:

Biogeographic patterns of soil fungal diversity have been well documented in forest ecosystems, but the underlying mechanisms and processes that shape these patterns remain relatively unknown. This study took soil samples from 300 forest plots spanning six forest types along a latitudinal gradient in eastern China, which ranges from tropical rainforest to boreal forest ecosystems. A null-model analysis was used to compare the observed soil fungal beta diversity (β-diversity) with the β-diversity expected from random sampling of each local species pool. We also compared the relative importance of environmental and spatial variables on soil fungal β-diversity among forest types along the latitudinal gradient. Our results found that observed β-diversity was greater than expected β-diversity in all six forest types, which means that species tend to be more aggregated than expected. We determined that this species aggregation resulted from both environmental filtering and species dispersal limitations. Further, environmental variables had stronger influences on β-diversity than spatial dispersions. Additionally, the co-occurrence network showed that more species interactions occurred in the mid-latitude forests which lead to decreased soil fungal β-diversity and low interpretations of environmental and spatial variables. Study of these processes in different forest types along latitudinal gradients will provide important insights that local differences in the relative importance of different community assembly processes creates different gradients in global biodiversity.

APA, Harvard, Vancouver, ISO, and other styles

44

Moreira, Xoaquín, Luis Abdala-Roberts, Hans Henrik Bruun, Felisa Covelo, Pieter De Frenne, Andrea Galmán, Álvaro Gaytán, et al. "Latitudinal variation in seed predation correlates with latitudinal variation in seed defensive and nutritional traits in a widespread oak species." Annals of Botany 125, no. 6 (December 20, 2019): 881–90. http://dx.doi.org/10.1093/aob/mcz207.

Full text

Abstract:

Abstract Background and Aims Classic theory on geographical gradients in plant–herbivore interactions assumes that herbivore pressure and plant defences increase towards warmer and more stable climates found at lower latitudes. However, the generality of these expectations has been recently called into question by conflicting empirical evidence. One possible explanation for this ambiguity is that most studies have reported on patterns of either herbivory or plant defences whereas few have measured both, thus preventing a full understanding of the implications of observed patterns for plant–herbivore interactions. In addition, studies have typically not measured climatic factors affecting plant–herbivore interactions, despite their expected influence on plant and herbivore traits. Methods Here we tested for latitudinal variation in insect seed predation and seed traits putatively associated with insect attack across 36 Quercus robur populations distributed along a 20° latitudinal gradient. We then further investigated the associations between climatic factors, seed traits and seed predation to test for climate-based mechanisms of latitudinal variation in seed predation. Key Results We found strong but contrasting latitudinal clines in seed predation and seed traits, whereby seed predation increased whereas seed phenolics and phosphorus decreased towards lower latitudes. We also found a strong direct association between temperature and seed predation, with the latter increasing towards warmer climates. In addition, temperature was negatively associated with seed traits, with populations at warmer sites having lower levels of total phenolics and phosphorus. In turn, these negative associations between temperature and seed traits led to a positive indirect association between temperature and seed predation. Conclusions These results help unravel how plant–herbivore interactions play out along latitudinal gradients and expose the role of climate in driving these outcomes through its dual effects on plant defences and herbivores. Accordingly, this emphasizes the need to account for abiotic variation while testing concurrently for latitudinal variation in plant traits and herbivore pressure.

APA, Harvard, Vancouver, ISO, and other styles

45

Poulin, R., and T. L. F. Leung. "Latitudinal gradient in the taxonomic composition of parasite communities." Journal of Helminthology 85, no. 3 (November 12, 2010): 228–33. http://dx.doi.org/10.1017/s0022149x10000696.

Full text

Abstract:

AbstractAlthough latitudinal gradients in diversity have been well studied, latitudinal variation in the taxonomic composition of communities has received less attention. Here, we use a large dataset including 950 surveys of helminth endoparasite communities in 650 species of vertebrate hosts to test for latitudinal changes in the relative contributions of trematodes, cestodes, nematodes and acanthocephalans to parasite assemblages. Although the species richness of helminth communities showed no consistent latitudinal variation, their taxonomic composition varied as a function of both host type and latitude. First, trematodes and acanthocephalans accounted for a higher proportion of species in helminth communities of fish, whereas nematodes achieved a higher proportion of the species in communities of bird and especially mammal hosts. Second, the proportion of trematodes in helminth communities of birds and mammals increased toward higher latitudes. Finally, the proportion of nematodes per community increased toward lower latitudes regardless of the type of host. We present tentative explanations for these patterns, and argue that new insights in parasite community ecology can be gained by searching for latitudinal gradients not only in parasite species richness, but also in the taxonomic composition of parasite assemblages.

APA, Harvard, Vancouver, ISO, and other styles

46

Skoblin, M. G., and M. Förster. "Steep latitudinal gradients of thermospheric composition during magnetic storms: a possible formation mechanism." Annales Geophysicae 13, no. 3 (March 31, 1995): 277–84. http://dx.doi.org/10.1007/s00585-995-0277-7.

Full text

Abstract:

Abstract. Mass spectrometer satellite observations show that a narrow region with steep latitudinal gradients of neutral composition is formed in the subauroral winter thermosphere during magnetic storms. In order to analyze the relative importance of individual terms in the continuity equation for atomic oxygen, a two-dimensional model was used to simulate the thermospheric disturbance formation in response to intense Joule heating imposed in the auroral oval. Such an approach allowed three characteristic zones to be distinguished in the high-latitude thermosphere at heights of about 250 km. It was shown that vertical transport is of greatest importance within the local heating region. Horizontal transport dominates at subauroral latitudes near the mid-night edge of the auroral oval. Propagation of the disturbances to middle latitudes is prohibited near the noon edge of the oval by a strong counteraction of a poleward meridional wind. Here is a "relaxation zone" defined as the region which is spread to the equator from the boundary between the local heating area and the subauroral zone in the noon sector LT. It is at this boundary that composition distributions with steep latitudinal gradient are formed within the first few hours of Joule heating source action. Perturbations transported to middle latitudes during the periods when the meridional wind is directed equatorward begin to relax in this zone with a characteristic time scale of about 7 h, independent of season. However, in winter, composition at subauroral latitudes recovers to unperturbed N2/O values before the wind again turns equatorward, giving rise to a distribution with steep latitudinal gradient recovering. In summer, a complete relaxation cannot be reached due to a shorter time interval with poleward wind and a larger disturbance amplitude. These two factors result in an effective smoothing of the initial steep gradient and a more regular latitudinal distribution of composition is observed in the summer thermosphere.

APA, Harvard, Vancouver, ISO, and other styles

47

Alroy, John. "Latitudinal gradients in the ecology of New World bats." Global Ecology and Biogeography 28, no. 6 (February 14, 2019): 784–92. http://dx.doi.org/10.1111/geb.12892.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Willig, M. R., D. M. Kaufman, and R. D. Stevens. "Latitudinal Gradients of Biodiversity: Pattern, Process, Scale, and Synthesis." Annual Review of Ecology, Evolution, and Systematics 34, no. 1 (November 2003): 273–309. http://dx.doi.org/10.1146/annurev.ecolsys.34.012103.144032.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Pulido-Santacruz, Paola, and Jason T. Weir. "Extinction as a driver of avian latitudinal diversity gradients." Evolution 70, no. 4 (March 31, 2016): 860–72. http://dx.doi.org/10.1111/evo.12899.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Baumann, Hannes, and Owen Doherty. "Decadal Changes in the World's Coastal Latitudinal Temperature Gradients." PLoS ONE 8, no. 6 (June 18, 2013): e67596. http://dx.doi.org/10.1371/journal.pone.0067596.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Latitudinal gradients'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles