Vegetation dynamics of Madayipara laterite hillock in relation to weather
Loading...
Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Academy of Climate Change Education and Research Vellanikkara
Abstract
Madayipara Laterite hills in Kannur District is a biodiversity rich area. The
geographical and climatical features make Madayipara and the adjacent laterite
hillock system support a unique assemblage of species. It is the home of unique
and sparsely distributed endemic plants such as Nymphoides krishnakesara, Rotala
malabarica, Justicia ekakusuma, Lepidagathis keralensis etc. In this study nine
different microhabitats were identified and the species composition noted each
month. A total of 52 plots of 5x5m were taken in 5 regions of Madayipara. Soil
samples were collected from 9 different microhabitats in the study site for soil
analysis. Daily weather parameters like temperature and humidity were recorded
using hygrometer whereas rainfall data was obtained from rain gauge installed at
the site.
In this study, a total of 100 angiosperm species were recorded which were
distributed in 9 microhabitats. The vegetation in December was dominated by
grasses like Arundinella leptochloa, Arundinella metzii and Ischaemum indicum.
From May onwards some grass species (Murdannia loriformis, Desmodium
triflora), began to flourish and the temperature was slightly lower than March
(30.5°C). After the dry phase, wet phase starts from June with the onset of
Southwest monsoon. Ephemeral flush vegetation and small ephemeral pools were
visible in the monsoon season with high species richness. Ephemeral flush
vegetation flourished with Murdannia loriformis, Utricularia reticulate,
Utricularia cecili etc. and small ephemeral pools were dominated by Parasopubia
hofmannii var. albiflora, Rotala malampuzhensis, Rotala malabarica and
Utricularia reticulate. Neonotis hohenackiri, Rotala malabarica and Utricularia
malabarica flourished from July onwards followed by Eriocaulon species. In
August, most of the microhabitats were occupied by Eriocaulon species. During
September the vegetation in soil enriched area and small ephemeral pools were
dominated by Murdania semeteres and Alysicarpus bupleurifolius.
Among all microhabitats Ephemeral flush vegetation (EFV) had high
species richness. About 37 species were present in EFV whereas only 8 species
were found in Boulders (B) which had the lowest species richness. The least
species diversity was observed in the microhabitats associated with the rock which
includes CEC, RCF and RB that had only 10, 12, and 8 species respectively. Only
2 (SRA and EFV, SRA and EP) of them out of 36 combinations were found to
have more than 50% similarity (Table 2) which clearly indicates the diversity of
habitats within the lateritic hillock. On the other hand, 1 microhabitat was found
to be 100% dissimilar.
Nitrogen, Phosphorus, Potassium, Calcium and Magnesium content in the
soil were highest during February and then during June. Available nitrogen is
lowest in the month of August. Crust edges or Cliffs show low nitrogen content
during august (44.78ppm) because of decrease in the amount of rain and
vegetation. Tree cover and tree associated microhabitats had low phosphorus
content of 1.16ppm during February. Among the microhabitats, soil enriched area
had the least K content and rock crevices had the highest K content. Rock crevices
had a K content of 145.14 ppm during February. Higher nutrient content in the
month of February is due to the burning of land and in June it is due to the
availability of rain and new species that emerge during the month. The sulphur
content was lower in the month of February because the burning of land reduces
the sulphur content in the soil. Nitrogen, Potassium, Calcium and Magnesium
content were lowest during August due to the decrease in rainfall and the nutrients
being used up by the plants.
Heavy rainfall coupled with high humidity results in high moisture content
in the atmosphere which enhances the vegetation and high temperature coupled
with low humidity reduces the vegetation. The correlation study showed that the
species richness is directly related to rainfall and humidity where as it was
inversely related with temperature. The correlations were highly significant. In this
circumstance, the regression analysis was done to make a model for prediction of
richness based on various climatic conditions.
Richness = 1.537386 * Humidity + 0.019341 * Rainfall -4.08193 * Temperature
+ 37.18196.
All the variables were significant in the regression with high precision.
In a recent study, Gopakumar (2017) has reported that the average
temperature of the state of Kerala has increased by 0.65°C during the period 1956-
2014. In future, Kerala will experience unprecedented warming due to natural and
anthropogenic reasons. In Madayipara, increase in temperature will adversely
affect the vegetation and may result in decrease in the number of species thus
affecting the biodiversity. Anthropogenic disturbances like brick and clay mining,
road and building construction, land filling, seasonal fire etc. together with biotic
pressures like invasion of exotic weeds cause serious threat to Madayipara.
Conservation and protection of the biodiversity of Madayipara deserves urgent
attention.
Description
PG
Keywords
null