1.    Plant Diversity

The coastal landscapes of Uttara Kannada, mainly from parts of Ankola taluk in the north to Bhatkal taluk in the south, are notable for spectacular formations of low level laterite hills and plateaus. The valleys in between them are good water yielding places, perhaps were ancient water courses through which greater volumes of waters flowed, before they were reduced, as are today, into a network of green veins running through an otherwise bleak spectacle of denuded low hills and plateaus. These coastal lateritic formations, in all probability lost most of their surface soils during the last three millennia of history of shifting cultivation and savannization for domestic cattle and to keep away predatory wild animals for safety of humans and livestock. Surface laterisation process, as was already explained earlier, resulted in formation of hardened, indurated mantle. These lateritic formations, most of which is under the control of the Forest Department, have been naturally considered as one of the most unproductive terrain, from early British times.

The woody vegetation on such hills was mostly composed of stunted trees and shrubs such as Sapium insigne, Strychnos nux-vomica, Zizyphus mauritiana, Plectronia parviflora, Grewia microcos, Flacourtia Montana, Ficus arnottiana, Memecylon edule, Syzygium corymbosa, Aglaia roxburgiana etc. The wetter valleys in between have more evergreen species which are also found in the Western Ghats further interior. Many sparsely populated villages and hamlets, along with their spice gardens and rice fields are situated in these valleys. The village cattle would be seen grazing in these hills, with of course poor forage for them, except in protected portions under private control, where grows tall karada grasses, cut and stored by farmers after the end of the rainy season, when these grasses start drying up.

What was often overlooked was the fact that during the period of torrential rains, especially from June to almost the close of September, most of these apparently barren hills turn into altogether a different kind of seasonal ecosystem of wet rocks, shallow bogs and marshes and temporary streams, teeming with numerous herbs in myriad flowers of varied hues which attract a variety of insects, especially bees and butterflies.

These laterite ecosystems have scores of species of herbs, many of them endemic to the Western Ghats west coast regions. The scarcity of nutrients in the rocky substratum favour here a flourish of insectivorous herbs, the bladderworts (Utriculalria spp.) and sundews (Drosera spp). These make up for t nitrogen deficiency in the medium by resorting to trapping of tiny insects and digesting them using specially modified leaves. Yet another group of plants are some members of the family of Scrophulariaceae, like Striga, Sopubia and Rhamphicarpa specialized in root parasitism. Some legumes here have root nodules with nitrogen fixing bacteria in them.

The general consideration of these lateritic formations as of not much utility to humans made the government to give concessions to local people to gather biomass from these hills for fuel, manure and fodder. Further, quarrying for laterite bricks, the most common building blocks of the district has been a rampant activity disfiguring the hills and causing damages to their special ecosystems as well as with adverse effects on local hydrology. As tree growth is sparse and slow, over the last three decades the forest Department raised in large scale monoculture plantations of the fast growing exotic tree Acacia auriculiformis, to meet the growing demand for timber, fuel and pulpwood.

We undertook this survey (Figure 1) specially to survey the vegetation of these laterite hills and plateaus, mainly with the purpose of protecting at least some of these primeval geological formations,  with great bearing on continental drift and formation of west coast, along with their for their very special seasonal ecosystems. Out of the many hills and plateaus surveyed during the current rainy season, we recommend specially two of them, one in the taluk of Bhatkal  (Bhatkal plateau) and the second in Mugali plateau in Honavar taluk.

Many exclusive species of flowering plants co-evolved with the laterite terrain micro-level heterogeneity. For instance, deeper lateritic bogs support Eriocaulon cuspidatum, shallow bogs Weisneria triandra while marshy areas have Utricularias and other species of Eriocaulons.  As water is the most critical limiting factor as soon as the rains stop by early October most of these annuals except few such as mat forming hardy perennial herb Lepidagathis prostrata and tuber perennating ones like Euphorbia fusiformis and Curculigo orchiodes die off. Of the two places that we found of the lot as having most specialized lateritic herbs, Bhatkal plateau had richer growth of herbs, since there were more seasonal streams, marshes and meadows. Mugali plateau had its own complement of species and includes as well as the newly developed and spectacular Apsarakonda park, towards its sea facing slope and commanding view of the ocean from the plateau.  In comparison was the thinner and sparser vegetation lower diversity of species of Gokarna and Belekeri study areas.  Honavar and Kumta laterite formations were intermediate in their biodiversity.

Scrub jungle vegetation with Memecylon edule, Flacourtia Montana, Canthium parviflora, Sapium insigne and plantations of cashew-Anacardium occidentale were found Mugali plateau. The rainy season splendor of herbal vegetation, especially of insectivorous plants and several rare endemics and the massive flowering at a time when most people hesitate to step into these rocky expanses, is remarkable. Not only these laterites are picturesque to look but they also support wide range of insects such as bees, carpenter bees, beetles, various butterflies etc. acting as a critical food resource for these species during the rainy period when flowering is scanty elsewhere. The numbers of plant species (mainly herbs) and the status of endemism, in Mugali-Apsarakonda lateritic plateau in comparison with that of Bhatkal plateau are given in the Figure 2. Both have excellent assemblage of species and high endemism levels despite openness and harshness of the terrain. Family richness of both the study areas is given in Figures 3 and 4.

 Figure 1: Examining microtopography linked plant species distribution in a laterite plateau

Figure 2: Floristics and endemism in Mugali and Bhatkal laterite plateaus

Note: Total endemics include India and Sri Lanka together

Figure 3 (L): Family richness in Bhatkal plateau; Figure 4 (R): In Mugali plateau

Table 1: Checklist of laterite plants in Mugali plateau of Uttara Kannada

Table-2: Checklist of laterite plants in Bhatkal of Uttara Kannada

2.    Fauna

The mammalian diversity was richer once because of the continuity of this hilly coast with the Western Ghat forests, before heavy human settlements and construction of the National Highway 17 and the Konkan Railway track. Heavy coastal traffic practically reduced major mammals. The laterite plateaus are however rich in certain special kinds of mammals like the pangolin and porcupines. Jackals are common and the wild boars sometimes foray into the region, especially in Bhatkal plateau, which also get occasional barking deers. Bird diversity is quite rich because of the nearness of sea, backwaters, forests, plantations and fields. Peafowls are very notable among the numerous birds. Detailed studies of mammals, birds and reptiles are yet to be taken up. The monitor lizard is a somewhat commoner species. These and pangolins are sometimes hunted for meat. Some kind of conservation status is likely to benefit both these rare species and many others.

Importance of laterite flora for insect diversity

Flower-visiting insects play an important role in maintaining biodiversity and ecosystem services such as pollination, which corresponds to a great economic value. Wild and domestic bees and other pollinators increase production of fruits and vegetables and many other kinds of crops significantly. The emerging threat of a global ‘pollinator crisis’ was expressed over a decade ago. Since then, declines of pollinator and other flower-visiting insects have been confirmed worldwide. The main driver of decline in flower-visiting insects is generally thought to be the loss of suitable habitat through land-use changes and other human activities. Among the various determinants of habitat quality, the loss of floral nectar resources has been most frequently proposed as a major factor contributing to flower-visiting insect declines. Pollination systems in which the host plant provides breeding sites for pollinators, invariably within flowers, are usually highly specialized mutualisms.

The enormous numbers of herbs that carpet the laterite plateaus during the rainy season flower from July to mid-September and some of them beyond for some more time. This period, especially July to August has very less flowering among the other wild plants, including forest trees and shrubs. The Utricularias, balsams, Eriocaulons, herbs of Scrophulariaceae and many others, which have their profuse flowering in the plateaus during the peak rainy period, act as keystone resources for pollinator insects, especially bees and butterflies and various dipterans. Therefore the conservation of laterite plateaus near every coastal village is necessary, at least as Biodiversity Heritage sites of respective villages.

Pollination systems in which the host plant provides breeding sites for pollinators, invariably within flowers, are usually highly specialized mutualisms. The non-butterfly insects identified were Apis dorsata var. dorsata, Apis cerana indica, Apis florea, Trigona sp., Xylocop sp. etc. List of butterflies found in the laterite plateaus during the rainy season is given in Table-3.

Table 3: List of butterflies found during rainy season foraging in laterite vegetation