Latitude is a measure of a location’s angular distance from the equator, ranging from 0° at the Equator to 90° (North or South) at the poles. Gradient refers to the direction and pace of the most rapid rise.
The gradient in latitude:
As we move away from the equator and closer to the poles, the diversity of species declines. There are more species in the tropics than in temperate or polar regions. Scientists have presented numerous explanations to explain the greater diversity in the tropics.
In most cases, speciation is a function of time. Historically, temperate regions were subjected to frequent glaciations. Tropical latitudes, on the other hand, have remained relatively unaffected over millions of years. In the tropics, this provided for a long evolutionary time for species diversity.
Tropical climates are less seasonal, and therefore more stable and predictable. A consistent environment encourages niche specialisation and increases species diversity. In the tropics, there is more solar energy accessible. It helps to increase productivity. It may have led to greater variety in the tropics indirectly.
Examples:
Although non-mammalian taxa dominate latitudinal diversity gradients outside of North America, the taxonomic and geographic consistency of latitudinal diversity gradients [61] suggests that the distribution of most of the world’s mammal species will contribute to a pattern of more species in warmer regions. Climate variables outperform landcover variables as predictors of species diversity or distribution [63,64], especially at large scales of comparison [65], but it’s unclear whether this is because the climate is the more important mechanistic driver of diversity or because it’s difficult to classify land cover appropriately for multiple species across a variety of landscapes. Regardless, the remarkable generality and strength of climate-diversity correlations across biogeographical space, as well as their correspondence with patterns over geological time, has positioned them at the centre of approaches to studying and predicting the effects of climate change on mammals and other animals.
Relationships between species and their habitats:
There is a link between species diversity and the size of the area.
Species diversity refers to the number of distinct species found in a given area. It also refers to species’ evenness, or how evenly species are dispersed in a given area. Species biodiversity is made up of species richness and species evenness. It rises in tandem with the number of regions explored. When species explore locations other than the one they originally discovered, they expand their habitat and so increase biodiversity. Other elements, like climate factors and the availability of food to maintain creatures, govern it.
As a result, species diversity will be proportionate to the region examined. It can be expressed mathematically as logS=log C + Z logA. Where S stands for species richness/equality. C stands for constant. The regression coefficient, or slope of the curve, is denoted by the letter Z. (which can be understood with the help of a graph drawn below). A has been explored or a specific area has been identified.
The effect of the mid-domain:
Africa and the Americas are continuous geographical masses that occupy equatorial latitudes and regions in both the southern and northern hemispheres. Consider a domain that is divided into three equal zones by a line (northern, central, and southern).
We would expect to find roughly 55 percent of species in each of the northern and southern zones, and approximately 80 percent of species in the middle zone, with many species in more than one zone, if species occupied random continuous latitudinal spans (segments of that line). Species Range: 5,10,15,20 Northern and Southern Central.
Species distributions along with a hypothetical southern-northern interval were chosen at random. Species are more likely to be observed in the central region by chance alone. Some ecologists believe that there doesn’t need to be any significant differences between temperate and tropical regions to account for a latitudinal species gradient, while others believe that mid-domain effects serve as useful null models against which to compare other explanations, based on simulation results based on this principle. For a variety of reasons, relying solely on this impact to explain patterns of species richness has been questioned.
- Species and population distributions are not chosen at random.
- Some initial patterns of species richness are not captured by the mid-domain effect.
- The history of evolution (phylogeny is ignored) The mid domain effect is compatible with data trends for various groups of animals, particularly wide-ranging species.
Cause:
When compared to temperate latitudes (near the poles), tropical latitudes (near the equator) contain a higher collection of species of living things, although the latter is disturbed by glaciers.
The climate in tropical latitudes is ideal for niche and living organisms. Climate change is unexpected in polar and temperate locations, and the atmosphere is not conducive to living organisms adapting to the changes. As a result, organisms either move or die in certain areas.
Tropical organisms will be able to thrive due to the greater availability of solar energy in comparison to temperate zones.
Temperature Gradients on a Latitudinal Scale:
The temperature drops as we walk away from 0° latitude, i.e. from the equator to the north and south poles. The Torrid Zone, which is located between 0° and 23°30′ North and South, receive perpendicular solar beams and thus has a high temperature. The temperature shifts represent the transition from greenhouse to icehouse conditions. The evolution of latitudinal temperature gradients is comparable in the marine and terrestrial domains, although there are several key differences. Temperatures in the ocean are often warmer than those on land. The presence of frontal systems in the ocean is shown by different inflections at 30° and 50° latitudes in the marine records.
Latitudinal Gradient’s Importance:
In the subject of biodiversity, the latitudinal gradient and species-area connections are two key ideas. These aid in the identification of numerous ecological patterns that occur on the planet. Using these notions, it is easy to see how species richness rises as one advance from polar to tropical temperatures. As previously stated, finding Biodiversity trends around the world is a necessary step in understanding ecosystems and reaping their benefits. Two significant strategies for determining such Biodiversity patterns are the latitudinal gradient and species-area connections.
Conclusion:
Moving from pole to equator, the pattern of increasing species richness is quite consistent. Several explanations have been proposed to explain this pattern. They all contribute to describing various aspects of the pattern, but they all have flaws. Multiple mechanisms are most likely involved.