The latitudinal gradient of biodiversity is a phenomenon whereby species richness is greatly reduced in areas outside of the tropics, (Gaston, 2007) which suggests that the areas that Harris . Latitudinal gradients in species diversity - Wikipedia This observation prompts a second, related goal in addition to explaining the latitudinal 90 diversity gradient: explaining why richness differs dramatically between realms even at similar 91 latitudes. The latitudinal biodiversity gradient occurs over such a large scale that it begs an explanation in which the determinants of species-richness at one location are the same determinants of species-richness at another location. Understanding the determinants of range location and size is fundamental to our understanding of spatial patterns in species richness. In general there are more species at lower latitudes. Location The gradient was studied for North and South America, between 430 N and 32' S. The pattern of having lots of species at the equator with diversity dwindling off towards the poles is known as the Latitudinal Diversity Gradient "latitudinal" meaning how far north or south of the equator, "diversity" meaning the number of species, and "gradient" meaning the transition between high and low. Phylogenetic data suggest that higher tropical species richness is attributable to a multitude of factors, including higher long-term diversification rates [11,12], niche conservatism , and more time for speciation [e.g., 14]. 120 . 1. highly productive environments sometimes have few species (spartina salt marshes and mangroves) 2. species richness often declines with very high ecosystem productivity. In most cases, the influence of the latitudinal gradient in species richness is the main aspect examined , which is considered the oldest manner to explain richness distribution . Camilo Mora, Department of Biology, University of Windsor, 401 Sunset, Windsor, Ontario, N9B 3P4 Canada. Total species richness showed no latitudinal trend. However, these patterns were not reflected in smaller-scale local species richness. Understanding the causative mechanism or mechanisms that generate the latitudinal gradient in species richness (LGSR) has been a major . 92 Present-day differences in species richness among drainage basins might be explained by Second, zonal bleeding of tropical species into extratropical regions smooths out species-richness gradients 7. Our results show a significant latitudinal gradient in species richness and turnover where local and regional species richness increase monotonically from higher latitudes to lower latitudes of the Western Ghats. The LDG is one of the most widely recognized patterns in ecology. Rosenzweig M.L. Search for more papers by this author. KEYWORDS diversification rates, freshwater fishes, generalized additive models, latitudinal diversity gradient, species richness, time for speciation The latitudinal gradient. Three possible explanations have been proposed for why a latitudinal species-richness gradient might be expressed: first, low productivity at high latitudes reduces the species richness they would gain as a result of area alone. Latitudinal gradients in species diversity explains the . Search for more papers by this author. group, were likely to display the classical latitudinal gradient in species richness. In particular, the favourability hypothesis in biogeography high-lights the potential importance of increased abiotic ltering Latitudinal Diversity Gradient, Geographical, Species, Species Richness, Taxa, Hypothesis,Biotic, Historical Perturbation, Climate Stability, Climate Harshness, Mid-Domain, Evolutionary Rate, Evolution. 4. Proc Natl Acad Sci USA 97:4082-4085 There are some Understanding the causative mechanism of mechanisms that generate the latitudinal gradient in species richness (LGSR) has been a major . Methods: We used species richness data from 245 local vascular plant floras to quantify the slope and shape of the latitudinal gradients in species diversity (LGSD) across all plant species as well as within each family and order. The best-known and most widely studied pattern is the latitudinal gradient in species richness (Pianka 1978, Huston 1994, Rosenzweig 1995). October-December 2018 531 drier forest patches alternating with floodplain savannas and palm marshes, which in turn are bordered to the south Introducing the LDG. Species Diversity in Space and Time. there is a strong bell-shaped latitudinal gradient in species richness with a peak at mid-latitudes (33-43 S). This pattern holds for marine and terrestrial organisms, for living 3. Here, we use Whittaker's definition of species diversity (SppD) to express species richness as a logarithmic function of sampling area (Whittaker 1970).Where, S is the number of tree species in all inventory plots of a latitudinal band and A is the total sampled area. The latitudinal diverseness gradient is the term used to depict the lessening in species richness as one moves off from the equator. PETER J. MAYHEW. Rosenzweig M.L. what is the latitudinal gradient? Plants, in particular, show an increasing biodiversity trend towards the equator [2]. The latitudinal diversity gradient, with maximum taxonomic richness in the tropics, is widely accepted as being pervasive on land, but the existence of this pattern in the sea has been surprisingly controversial. (stem abundance, tree size variation and stand basal area) and tree species richness to . The pattern usually observed is the increasing of species richness toward the equator, which can be explained by various hypotheses [2,17,18]. It has been suggested that this is because species from the tropics spill out of this region of high richness, artificially . CAUSES OF LATITUDINAL GRADIENTS IN SPECIES RICHNESS: A TEST WITH FISHES OF THE TROPICAL EASTERN PACIFIC. 2. Species Diversity in Space and Time. The high numbers of tree species experiencing density-dependent mortality in the tropics is sometimes hypothesized to explain the latitudinal gradient in species diversity 4,5,6.Our results . The latitudinal diversity gradient is the term used to describe the decrease in species richness as one moves away from the equator. indirectly, with more species at higher stem abundance. This is partly due to Thorson's . abstract: The species-area relationship (SAR), describing the in-crease in species richness with increasing area, and the latitudinal di-versity gradient (LDG), describing the decrease in species richness with increasing latitude, are the oldest and most robust patterns in bioge-ography, yet connections between them remain poorly understood. Latitudinal Gradients Describing Biodiversity Pattern in Species. E-mail: moracamilo@hotmail.com. This area model is appealing in its logic, but there is [ 1 ] Discovered by Alexander von Humboldt in 1799, it has remained one of the cardinal inquiries in Evolutionary Ecology. Palm species richness, latitudinal gradients, sampling effort, and deforestation in the Amazon region Diagramao e ML SciL Publishing Schema: wwweditoraletra1combr Acta Botanica Brasilica - 32(4): 527-539. Biogeogr.) 2. 2. The latitudinal gradient in species richness, wherein species richness peaks near the equator and declines toward the poles, is a widely recognized phenomenon that holds true for many taxa in all habitat types. The diversity of living things generally peaks in the tropics and declines toward the poles. a. more space for isolation and speciation. Cam-bridge University Press, Cambridge, p 94-121 Rex MA, Stuart CT, Coyne G (2000) Latitudinal gradients of species richness in the deep-sea benthos of the North Atlantic. IntroductionOne of the grand scale ecological patterns is a latitudinal gradient in species richness. The decline m species nchtiess with increasing elevation IS widely accepted as a general pattern (Table 1) In as much as the elevational gradient is often claimed to mirror the latitudinal gradient, spectes richness is assumed to decrease monotonically (l e because of reduced temperature and consequent decrease in producUvity) Perhaps because . The LDG has been observed to varying degrees in Earth's past. The results showed that there were clear latitudinal gradients in regional species richness and in species turnover among shores. (2008) 35, 394-406 SPECIAL High tropical net diversification drives ISSUE the New World latitudinal gradient in palm (Arecaceae) species richness Jens-Christian Svenning*, Finn Borchsenius, Stine Bjorholm and Henrik Balslev Department of Biological Sciences, University ABSTRACT of Aarhus, Aarhus C, Denmark Aim Species richness exhibits striking . / Areas cradles and museums : The latitudinal gradient in species richness.In: Trends in Ecology and Evolution. area hypothesis (abiotic) 1. larger area leads to. 119 . Principal among these patterns are the species-area relationship, as well as latitudinal, elevational, and topographic gradients. 89 2A). Third, recent events seem to impact local richness within a 103 continent, but differences in richness among continents remain (Oberdorff et al., 1997; Tedesco under aCC-BY-NC 4.0 International license. [1] Discovered by Alexander von Humboldt in 1799, it has remained one of the key questions in Evolutionary Ecology. Page: 1 of 5. The latitudinal pattern of tenebrionid (Coleoptera Tenebrionidae) biodiversity on the Aegean Islands (Greece) was analysed. better understand drivers of latitudinal tree diversity patterns. Willig and Lyons (1998) came close to an analytic geometry approach, but considered the earth to be a Brown and Gibson 1983), and species numbers, diversity and richness are used inter-changeably. species diversity in the deep-sea benthos. Using primary data from 156 (0.06 ha) plots comprising 20,400 occurrences of more than . 1,2 . To remove the obvious influence of area on species richness, several species-area relationships, including power, exponential, negative exponential, logistic, Gompertz, Weibull, Lomolino, and He-Legendre functions, were applied. University of Johannesburg, Johannesburg, South Africa. The pattern is abundantly clear. Here, we use geographic and evolutionary data for over 12,500 species of woody flowering plants to test the "tropical conservatism hypothesis," which attributes the . 15, No . This empirical pattern has been demonstrated for a wide variety of plant and animal taxa (reviewed in Rosenzweig 1995).Many hypotheses have also been proposed for these latitudinal patterns of species richness, such as productivity gradients, Rapoport's rule . boundary, a trend evident only in species richness gradients of more narrow-ranging species. Testing the link between the latitudinal gradient in species richness and rates of molecular evolution L. BROMHAM* &M.CARDILLO *Centre for the Study of Evolution, School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK Gradient: "direction and rate of fastest increase". The latitudinal gradient in species richness is one of the most ubiquitous ecological patterns in nature . Chaetoceros castracanei, C. flexuosus, C. criophilus, Porosira mechanisms have been proposed to explain latitudinal pseudodenticulata, Fragilariopsis curta). Although the real sampled area of 4 subplots in each inventory plot is ~ 672.5 m 2, each inventory plot spreads out across . In most cases, the influence of the latitudinal gradient in species richness is the main aspect examined , which is considered the oldest manner to explain richness distribution . The latitudinal gradient in species richness is perhaps the most fundamental pattern of biodiversity, yet a satisfactory explanation for its existence remains elusive. A recent attempt to explain latitudinal diversity patterns (Stevens, 1989;Ruggiero, 1994; but note exceptions and problems in Rohde et al., 1993;Rohde, 1996;Lyons and Willig, 1997) invokes a correlation between geographical range of species and the environmental variability within that range. 1).Historically, research has focused on gradients of species richness (i.e., the number of species in an assemblage) because that was the only information . Therefore, richness gradients in marine and terrestrial systems do not Like most nearshore One hypothesis for the latitudinal gradient in species richness observed in most animal taxa is that the richness of a region is determined by its geographic area. There are lots of taxonomic groups that show latitudinal . Higher temperatures, greater climate predictability, and longer growing seasons all conspire to create a more . We found strong support for Rapoport's Rule with an increase in range size from lower to higher latitudes; our results are consistent . A parallel trend has been found with elevation (elevational diversity . Journal of Biogeography (J.
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