Red-bellied Piranha spotted from Godavari River in Andhra Pradesh; new invasive threat?

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Red-bellied Piranha (Pygocentrus nattereri)
(Image Credits: Gregory Moine/ WikiMedia Commons under CC by 2.0)

Native fish fauna of Indian rivers gets yet another threat to their existence. According to researchers from India’s premier wildlife research body, Wildlife Institute of India (WII), a new ferocious predator fish has entered the Godavari River basin in Andhra Pradesh. Red-bellied Piranha (Pygocentrus nattereri), a known invasive species, was never reported from river systems in India before.

Native to Brazil, Red-bellied Piranhas are usually found in the Amazon and other coastal rivers, interconnected wetlands and canals of Brazil. As per earlier research, these ferocious predators are known to attack even healthy animals for food, not to mention other fish species. Often, when a predatory invasive species is introduced, it wipes away the native species, either by predation or through competition for food resources.

 As per an observation recorded by WII researchers, J.A. Johnson, R. Paromita and K. Sivakumar in MIN, an official newsletter from the IUCN-SSC Freshwater Fish Specialist Group South Asia and the Freshwater Fish Conservation Network of South Asia, the Red-bellied Piranha was found from Rajamundhry. 

“Our preliminary enquiry in the field revealed that this species is occasionally found in fisherman catch at Dhawaleshwarm barrage in Rajamundhry,” says the note published in MIN. As per the researchers, Red-bellied Piranha is being cultured around the Godavari River mainly in inland water and canals, from where it could have reached the Godavari River.

The situation is alarming, warn the researchers. “As it is a predatory and aggressive carnivorous fish, it may compete with native species for food and other resources, which will eventually lead to the decline or even extirpation of many native fishes in the river system”, they said.

As in case of many other major invasive threats to the Indian fish fauna, here again aquarium trade is the culprit of introducing this Brazilian native to Indian waters. According to Ichthyologist Dr. A. Bijukumar, Red-bellied Piranha was introduced in India as part of illegal aquarium trade. In a study published in 2000, he has warned that the fish, if establishes itself in natural streams, would be dangerous. The notorious fish is now available for purchase in many aquarium shops.

According to a study published in 2011 on non-native fish species in India, not less than 324 alien fish species have been introduced in India, mainly as ornamental fishes for aquarium trade, for cultivation and for killing mosquito larvae. However, many of them have turned invasive and destructive to the existence of native fish fauna. Many of these invasive fishes are threatening endemic fish diversity of Western Ghats, a world heritage site.

Researchers warn that unless agencies and activists take immediate steps to bring awareness to the fish farmers and aquarium traders to bring down the production and distribution of this potential invasive species, Red-bellied Piranhas may soon be detrimental to the fish diversity of Godavari basin. 

Fish fauna in Bharathapuzha under severe threats, warn scientists

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A view of Bharathapuzha (Image Credit: Wiki Media Commons/ Jjvellara)

Implement urgent conservation efforts or the rich and endemic fish wealth in the largest river in the Western Ghats of Kerala will remain only on papers, warns a new assessment on the threats to the fish diversity in the Bharathapuzha River, locally known as River Nila.

Through a survey on all the four major tributaries of the Bharathapuzha River system - Gayathripuzha, Chitturpuzha, Kalpathipuzha and Thoothapuzha – the study recorded 117 species of fishes in Nila with the highest species richness from the stretch between Parali to Purathur estuary. Among this, 33 are found only in Western Ghats and three are found only in Bharathapuzha River system. 

A group of researchers including A Bijukumar, Department of Aquatic Biology and Fisheries, University of Kerala, Siby Philip from Department of Zoology, Nirmalagiri College, Koothuparamba, Anvar Ali and Rajeev Raghavan from Conservation Research Group, St Albert’s College, Kochi and S Sushama from Department of Zoology, NSS College Ottapalam carried out the study which is published in the Journal of Threatened Taxa.

Top Ten Threats to River Nila

Despite the richness, the river system of River Nila is under threat from human interference, says the study which is published in the Journal of Threatened Taxa. “Several anthropogenic stressors including deforestation and loss of riparian cover, dams and other impoundments, pollution, sand mining, non-native species, climate change and destructive fishing practices are threatening the fish diversity of Bharathapuzha River system”, it says.

Threat #1: Sand mining

Most notorious, most widely known but most rampant, despite being regulated (encouraged ?) by the il-legal machinery. If we number the threat based on the calamity it brings, this one goes to top. The study marks the region between Pattambi and Thiunavaya as the superhot stretch of legal and illegal sand mining. Studies conducted by CESS in 1997 itself has shown that the rate of sand mining is way too above the rate of sand generation in Nila. For many fishes in Nila, Sand is the breeding substrate, and is the single crucial link that supports the aquatic food web. With the indiscriminate sand mining, it is just a matter of time for fishes like Glossogobius giuris and Sicyopterus griseus to vanish from Nila forever, warns the study.

Threat #2: Dams and impoundments

Known fact: Big dams are a major threat to the rich and endemic fish diversity of Nila, since they change the turbulence of the river causing high sedimentation and other problems. Lesser Known fact: Dozens of smaller check damk dams across Nila are also doing the same. Bigger dams are fixed in number so far – Nila has 11 irrigation dams. Impoundments are still proliferating, turning out to be a lesser noticed diversity killer in Nila. It has severely affected the movement of certain fish species and is believed to be a reason for the near absence of eels in the river system.

Threat #3: Pesticide pollution

When it comes to a River system like Nila, don’t think it is just the factories that are pushing chemicals to the water. River basin dependent extensive agriculture and plantations are also contributing their fair share to polluting this blood line of middle Kerala. Chemical fertilizers, pesticides, chemical nutrients, weedicides, you name it. The resulting eutrophication- the facilitation of aquatic plant growth which in turn decreases the available oxygen in the water, killing the aquatic fauna- is a major issue, especially from Chamravattom to Purakkad, says the study.

Threat #4: Urban sewage

Read Pattambi. According to the study, the town of Pattambi which falls under the Palakkad District of the state of Kerala is a major source of urban sewage which pollutes the river extensively, taking over the pollutant cocktail made by the agro-pollutants. “The urban sewage canals directly open into the river, through which the municipal waste is dumped. Such large scale pollution not only degrades the habitat but also causes endocrine disruptions and several other physiological imbalances in fish including breeding failure which could ultimately lead to their extirpation”, says the study.

Threat #5: Deforestation

According to the study, deforestation in its catchment areas like Mangalam, Nelliyampathy, Walayar, Malampuzha, Nellipuzha, Dhoni and Kalladikode is a major threat. The loss of natural native vegetation has triggered the invasion by exotic plants. Not only that the fishes loose a food resource, the high sedimentation rate due to deforestation is changing the natural composition of the river bed. It makes survival difficult for many endemic loaches in the river since they use the pebbles in the river bed for breeding.

Threat #6: Lime stone mining

Lime stone mining is rampant in certain areas of the catchment of the river, says the study. This is especially prominent in Malampuzha, part of the Kalpathipuzha tributary. The study claims that the lime stone mining in the catchment areas is leading to pollution and siltation in the stream. Apart from triggering an unnatural rise in the silicate content in the water, the dumping of mining debris also damages smaller streams in the system like Seemanthinipuzha.

Threat #7: Alien species

The study has spotted at least six non-native fish species in Nila. While three of them were non-native to Indian rivers, three were from the Gangetic plains. Though the Indian major carps were introduced as part of aquaculture, considered as a success, the study was able to spot them from lower reaches of the river, revealing that they have proliferated though the river beyond their actual reservoirs. Such proliferation of non-native species often wipes out native species in the fight for resources. Species foreign to India like the Nile Tilapia and Mozambique Tilapia were also spotted from Nila, showing that the alien invasion is possibly stifling the endemic fish fauna of the river. However, the surprise factor was that the study reportedly failed to fetch another notorious alien species – African catfish- which is a known diversity killer in Western Ghats Rivers.

Threat #8: Climate change

Studies conducted in 2010 and 2011 discovered that the temperature in the Bharathapuzha basin has been on the rise for a 36 year period from 1969 to 2005. Moreover, rainfall data shows that the Nila watershed gets less rainfall than the state average. Though the temperature rise is often cited as an impact of climate change phenomenon and the increasing anthropogenic pressure in the river banks of the Nila, its effect on the biodiversity of the river system is scarcely studied.

Threat #9: Aquarium fish trade

 Comes in many colours –state supported as well as clandestine. This greed trade is especially wiping away endemic and beautiful fishes like Miss Kerala (Sahyadri denisoni) and Mesonoemacheilus remadevii, the latter being found only in river system in Silent Valley which is part of the Bharathapuzha River System. As per a recent study, Miss Kerala has been found to be collected in massive amounts from Thoothappuzha tributary for pet trade.

Threat #10: Destructive fishing practices

Last, but not the least, as always. Poisoning, use of mesh nets and dynamiting – small effort, good catch. Though traditional fishermen abstain from practices like dynamiting, it is raising a major threat to the fish diversity in the tributaries where the traditional fishermen are lesser in number, warns the study.

Action Time: Conservation Points to save Nila

• Prioritizing integrated watershed programmes.
• No more new medium or big dams, cautious about new check dam proposals.
• Channelize district River Management Fund to Eco restoration of stretches of Nila.
• Regulation of sand mining has been proved to be futile. So finding an eco-friendly alternative to sand is the only option left. But that will be like legalizing marijuana- you have to first convince the cartels before you convince the government. (They will have to take it, since the sand is running out and the weed is on the rise).
• Beg people not to use pesticides or agro-chemicals near the river bed cultivations (otherwise also).
• Regulate large scale riverbed cultivation.
• Establishing Aquatic Biodiversity Management Zones (ABMZ) to conserve river stretches known to shelter endemic and rare fishes.
• Regulate the greed pet trade and destructive fishing practices, not to say dynamiting.
• Above all, let people know – ask them, request them, beg them, threaten them – You may go the extreme since water is the life blood of the green earth, as River Nila is for Kerala.

High Time to Formulate Policies to Tackle Alien Species in India, says experts

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It’s time for an all-out war with the aliens, at least in the protected forest areas, but we lack policies, says a group of conservation scientists in the country. Invasive Alien Species (IAS) of plants are the second largest threat to the diversity of the forests, behind habitat fragmentation, but the conservation policy makers are yet to swing into action to tackle the issue, alleges a group of scientists while reviewing the status of IAS in the country and related conservation laws in India.

Lanatana Camara flowers
Image courtesy: Obsidian Soul/Wikimedia Commons

According to an article written by them in the Current Science journal, plants like Chromolaena odorata, Lantana camara, Mikania micrantha, Mimosa diplotricha and Parthenium hysterophorus are some of the major invasive alien plant species in India which are spreading rapidly in protected areas (PAs), suppressing the growth of the native flora. The alien menace has affected birds, animals and has not even spared the tribal populations depending on forests, it says.  “Large numbers of forest dependent communities still depend on forest resources and their livelihood is at stake due to pervasive landscape alteration by major IAS in different parts of India,”, says the article.

Lack of policies and distorted interpretations

Though the threat and impact are high, most of the protected areas in India do not have a clear and active eradication programme to tackle IAS, mainly because of lack of awareness among wildlife officials and their twisted interpretation of the conservation laws in the country. Wildlife (Conservation) Act, 1972, which is the major legislation regarding protected areas in the country, prohibit harvesting or removing any plant or animal materials from the PAs. This is raised as a major reason by protected area managers for not taking active eradication programmes against invasive plant species.

Chromolaena odorata
Image Courtesy: Ashasathees/Wikimedia Commons

Moreover, the Protected Area managers and policy makers are yet to understand the importance to eradicate IAS. Most often, the notions of the officials often end up encouraging exotic species. “Their (PA managers’) species selection for plantations is based on three criteria: (a) fast growth, (b) good timber value and (c) unpalatability to game species. These criteria encourage the planting of exotic species …….in effect replacing one IAS with another alien species”, points out the write-up. According to it, some of them even think that IAS likeLantana are good for the animals since it give them cover to hide. But they forget that “such a role was played by indigenous understorey species prior to being replaced by vast swathes ofLantana, now dominant in many PAs”, it says.

How to eradicate Invasive Alien Species?

Removal of invasive plants from an area of infestation is not an easy job, since most of them show extra-ordinary abilities to reestablish themselves in the areas. “The seed bank of the major IAS remains and hence reinvasion occurs rapidly. Some IAS, such as Lantana, which are buried deeply can be stimulated to germinate when exposed to light and fire”, says the experts.

Presently, whatever nominal eradication programmes run in some protected areas are very narrower in their nature since they focus only on removing the IAS for the purpose of making fire lines. However, there is a need to develop early detection mechanisms to spot the menace when it begins so that the eradication is easier, constant monitoring to prevent spread of the IAS and resulting forest fragmentation.

Lantana Camara growing rapidly suppressing native plants in a farmland in Kangra District, Himachal Pradesh 

Manual removal is the best practice so far observed to tackle the menace, according to the article. Though it is very effective in small areas, it may not be so for large areas since the estimated cost of manual eradication is anything between 4000 to 5000 Rupees per hectare. But implementing any such measures on a wide scale may not be possible in the absence of legal provisions to facilitate it.

However, there is a possible way out, according to the experts. According to them, the issue can be raised with the Supreme Court appointed Central Empowered Committee (CEC) which can submit recommendations and suggestions to review existing conservation legislation to tackle the issue. So the ball is in the court of conservationists in the country. “We see a compelling case for scientists/managers to approach the CEC for clear guidelines and exemptions regarding programmes for the vigorous control and removal of IAS from the PAs.”, says the article.

Fighting the aliens at Periyar Tiger Reserve

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Periyar Tiger Reserve (PTR) is not just a safe haven for the tigers, but for some aliens too, in the ecological sense. African cat fish (Clarias gariepinus), one of the most dangerous invasive alien species, is lurking in the Periyar Lake, raising serious threat to the rare fishes found only in Periyar, say researchers. To bring a twist to the story, PTR is going to have the first of its kind action against exotic fish species in Western Ghats as a group of researchers and activists are aiming to manually remove African cat fish from Periyar with public participation.

African Cat Fish (Clarias gariepinus)
Image Credit : W.A. Djatmiko (Wikimedia Commons)

According to Conservation Research Group- a research and activist platform based in St Albert’s College in Cochin- which organises the exotic fish removal campaign at Periyar Tiger Reserve, the endemic fishes found in the Periyar Lake are severely threatened by the biological invaders like African Cat fish, which inspired them to organise such a crusade against the alien fish species of PTR.  “Eight endemic fishes in Periyar Lake are fighting for survival as their only remaining habitats are threatened by several stressors of which biological invasion is the most significant one.”, says an official statement from the group.

Importance of Fish fauna in Periyar Lake

An on-going Rufford Foundation supported project to study the impact of alien species in Periyar Lake points out that the fish fauna in the Lake are very unique and valuable. “It (The Lake) holds the only remaining population of six globally threatened endemic fish species viz. Crossocheilus periyarensis, Garra periyarensis, Hypselobarbus periyarensis, Lepido pygopsistypus, Nemacheilus menoni and N. Periyarensis”, it says. According to an IUCN report on the Status and distribution of freshwater biodiversity in the western Ghats, Lepido pygopsistypus  is the only member of its subfamily of snow trout fishes to be reported from south of Himalayas.

According to the researchers, there are four exotic fish species found in Periyar Lake which comes under the reserve among which African Cat fish is the most dangerous one when it comes to threat to native species. Cyprinus carpio, Oreochromis mossambicus and Poecilia reticulate are the other exotic fish species found in the Periyar Lake Stream System (PLSS). Recent studies have indicated that the population of these exotic fish species are showing an increase which means that the threat to native species is growing. “C. carpio and O. mossambicus now dominate the fishery of Periyar Lake and are known to compete with endangered species such as L. typus and Crossocheilusperiyarensis”, says a recent study report issued by IUCN.

The invasive species have swept away many native fish species found in the lake earlier. During the last 50 years, at least 16 fish species earlier found in the lake has disappeared, say researchers.

Fighting the Aliens

African Cat fish in Periyar Lake and other freshwater ecosystem in Western Ghats is the usual story of an introduced species turning viral threat to native species. African Cat Fish was once widely used as a farm fish in Kerala and elsewhere for its rapid growth. It soon became very popular with its ability to survive in a range of water qualities and to devour anything from slaughter house waste to standard fish foods. However, the alarm started ringing when some of them have escaped through the natural water channels from fish farms during monsoon and reached the fresh water systems in Western Ghats. 

Exotic Fish removal campign at Periyar Tiger Reserve

The IUCN report has suggested that “the biggest future challenge to fish conservation in PLSS will be the management and control of C. gariepinus, whose opportunistic strategy and ability to establish large and persistent populations makes it an imminent threat.”

To fight the alien menace, a workshop conducted by researchers and forest officials at PTR in December 2012 has decided to take pro-active action against the invasive species. Field work has revealed high population of African cat fish in the canal draining into the Lake. The authorities and researchers are planning to net out the exotic fishes from the canal and manually remove the exotic fishes from the Lake. The organisers of the event were not available for immediate comment. However, according to an official invitation, the programme is scheduled on April 29^th and 30^th of this month. 

North American weed spotted in India, could be major threat to agriculture and forests in future

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If the initial hints are anything to believe, the farmlands and forests in India have a brand new invasive threat from a rarely reported foreign plant species native to North America. A recent research correspondence published in the Current Science journal claims to report the plant for the first time from India and argues that the plant can have tremendous invasive potential.

Western ragweed (Ambrosia psilostachya)
Image courtesy: Krzysztof Ziarnek Kenraiz (Wikimedia commons)

 According to the researchers, the plant is presently reported from farm lands in the M. Bevinahalli village in Turuvekere taluk of Karnataka. On close examination and surveying the literature, the researchers were able to identify the new plant as Ambrosia psilostachya. Though the plant resembles its close relative Ambrosia artemisiifolia which is found in India, it is actually different, says the correspondence. 

Its Indian variety, Ambrosia artemisiifolia, was the only member of the genus hitherto reported from India. According to the correspondence, the new weed is native to North America and is known as perennial rag weed or western ragweed in North America.

New invasive plant threat in India

The research note warns that the weed has tremendous capacity to spread very rapidly and is known to cause allergic reactions in Humans. “If the weed is not controlled now, it may create a difficult to control situation once it proliferates from the location of present report”’ says the correspondence. 

According to the correspondence, the weed has not only invaded finger millet, mulberry, coconut and areca nut cultivation  but has also conquered the cattle pastures which have affected animal husbandry of these villages. The correspondence also notes that the plant has seriously affected local flora, by replacing local grass varieties, thus decreasing fodder availability. 

The plant is capable of spreading to large areas through extensive vegetative reproduction through underground rhizome like roots and stolon (part of the plant which makes new plant).  Though the plant has been present in some villages in Karnataka for the last 15 to 20 years, it is not yet clear what restricts it from spreading to other places.

 According to the researchers, since the plant does not have parts which supports seed dispersal through wind, the plant has not yet started spreading to other places. It is also not clearly known at this point if all the seeds produced by the plant are viable or if they exhibit any type of dormancy.

Though, there are not many issues reported about this plant expect its rapid invasion of farm lands in Karnataka Villages, reports from other countries indicate that the plant can cause allergic diseases in humans. “The species is said to be responsible for causing severe allergenic diseases in human beings in the United States”, says the correspondence.

The North American Connection

The plant is actually native to North America and the way in which it has reached Indian farmlands is still unknown. Though some speculates that the seeds could have been brought to India by migratory birds that use the seeds and other parts the plant for making nests, the connection is yet to be scientifically proved.

Though contaminated food grains are a usual way in which invasive plants reach farther places -as in the case of Lantana, a notorious weed in Indian forest- that may not be the reason for the spread of the present weed. “The introduction of the species through contaminated food grain may not be possible, as the weed is localized only in these villages in Karnataka”, says the paper.

The plant has already spread to parts of South America, Europe, New Caledonia, Japan, Taiwan and Australia. The researchers do not rule out the chances that the seeds reaching India from either of these places.

Weed control measures

 The presence of root buds, horizontally running rhizomes and dense root ramification makes the plant difficult to manage and eradicate. Periodical manual removal, shallow plowing before passing cultivator in farms has been recommended as a control measure. According to the note, if repeated control measures are taken, the weed can be controlled in 4 to 5 years from the country with its present restricted proliferation.

 M. T. Sanjay  and T. V. Ramachandra Prasad from the Directorate of Weed Science Research Centre, University of Agricultural Sciences, Bangalore, R. A. Sharma from Directorate of Weed Science Research, Indian Council of Agricultural Research, Jabalpur and R. R. RAO, from Bangalore co-authored the correspondence.

Read more on IBT's coverage on invasive species in India.

Indian plant Ricinus communis among invasive threats to world’s second largest lake

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Short URL for the story: http://goo.gl/0529P

According to a new report published by the Invasive Species Initiative under the International Union for Conservation of Nature (IUCN) , the Caster oil plant which is native to India is one of the invasive plants that raise a major threat to the second largest and second deepest lake in the world – Lake Tanganyika - shared by  Burundi,Zambia,Tanzania and Democratic Republic of the Congo (DRC) .

Dense Growth of Ricinus communis

The report says that Ricinus communis, commonly known as Castor oil plant in English and Kadalavanakku in Malayalam, is a usual plant found in India. The plant, according to IUCN report, has shown invasive nature in other habitats and is a major invasive threat to Lake Tanganyika.

Lake Tanganyika has at least 250 species of endemic cichlid fish and many endemic water plants. But the presence of invasive plants around the lake is threatening the natural habitat of the lake as well as the existence of native fauna and flora.

The invasive zeal of Ricinus communis

Biological invasion is a wide phenomenon seen across the globe. It happens when a non-native species is introduced to a new environment, and it spreads virulently to cause damage to native organisms. Ricinus communis, due to its invasive nature, now has spread across all the tropical regions, says the report.

According to the study, the invasive nature of the plant makes it capable of displacing native plant species from a habitat. The impact will be more visible in the case of riparian areas and drainages. The seeds of the castor oil plant also give the plant some upper hand among native plants, shows the report.

The Castor oil seeds have a worthy appendage known as caruncle which attracts ants as the major seed dispersal agents for the plant.  Moreover, the seeds are among the first to germinate after a fire season, allowing the plant to have a competitive advantage over other native plants over the fight for resources.

Lake Tanganyika
Image courtesy : Google Maps

The plant is a fast growing suckering perennial shrub and often attains the size of a small tree. Due to this nature, when they colonize in already disturbed habitats, they grow faster, often shade over the native plants and seedlings, gradually weakening the strength of the native plant species.

Major reasons for the spread of the plant

According to the study, the ornamental plant trade is a major source through which the plant has got its grip around Lake Tanganyika . The practice of cultivation for extracting Castor oil is also a reason, points out the study. Apart from these, road building machinery, earth moving equipment and dumped garden waste also spreads the seeds of the plant.

The study which is preliminary in nature is the first of its kind to take place at Lake Tanganyika. It has listed 31 invasive plants which are raising serious threat to the water body.

The lone bat species in Kutch district threatened by serious habitat destruction near Hamirsir Lake

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Bhuj is gradually recuperating from the devastating earthquake which claimed 12290 lives in 2001. Now, the developmental activities are at full swing, the wreckage is being replaced by new constructions. However, the developmental and rehabilitation activities around the Hamirsir lake in the Kachch district is adversely affecting the population of the lone bat species in the district in the Indian state of Gujarat, the Indian flying fox (Pteropus giganteus).

Indian flying fox (Pteropus giganteus)
Image courtesy: Wikimedia Commons

Fondly called as 'Vagol' in local Guajarati, the bat species is the only large-sized fruit bat species found in Kachchh District. According to a research correspondent published in the latest issue of the Current Science Journal, the bat species has been using the small vegetation patches near the Harmisir Lake as a major roosting site. However, it is facing serious habitat destruction due to cutting of large trees in and around the lake as part of the reconstruction and developmental activities, says the correspondence reported by researchers at the Institute of Desert Ecology, Gujarat.

“The reconstruction and developmental initiatives have resulted in the cutting down of large trees which had provided shelter to the flying fox population in the past.  The natural habitat like forest patches and larger trees are disappearing due to rapid industrialization, urbanization” says the correspondence.

Disturbance from Laser shows

Moreover, the tourists activities in and around the lake are also taking a toll on the Indian flying fox population here. The influx of tourists and the resulting vehicular traffic are additional threats. According to the correspondence the laser light shows during the ‘Kutch Carnival’, a tourist fest, is also disturbing the Indian Flying Foxes in the area.

According to the correspondence, the wide presence of an invasive plant Prosopis juliflora, is also posing a major threat to the natural habitat of this bat species in Kutch district.

Conservation significance of Pteropus giganteus in Kutch

Earlier studies have shown that bats usually play a major role in pollination and seed dispersal of many plant species. Since it is the lone bat species in the district, it will be crucial in the pollination of many plants in the area. The disturbances caused to the habitat of the organism will thus take a toll on the population of many plants here thus bringing down the quality of the eco system, points out experts.

Though Indian Flying Fox is categorized under the Least Concern group in the Red Data book of IUCN, experts point out that the population trend of this organism is decreasing.

Calling for immediate attention towards the conversation statusof bats, the correspondence says that the bats have been given a least conservation priority in the area.  

“The time has come for the conservation of all animal groups, including the Flying Fox for maintaining ecological balance and conservation of biodiversity”, says the correspondence. 

Do you think conserving Indian flying foxes in Kutch as important? Share your views in the comments. 

Invasive plant Acacia dealbata reported from the high altitude Himalayan forest of Kedarnath wildlife Sanctuary

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Indicating an early sign of proliferation of invasive species in the Himalayan forests, as expected to happen during the phenomenon of global warming, a group of researchers has reported the presence of Acacia dealbata - an invasive alien plant - from the interior of the high altitude protected area of Kedarnath wildlife sanctuary situated in the Indian state of Uttarakhand.

Acacia dealbata in bloom
Photo courtesy :Wikimedia Commons

The team has spotted the plant at an altitude of 2200 from the mean sea level, which makes it the first report of the species from such a high altitude of Garhwal Himalayas, says a research correspondence published in the Current Science Journal. It also turns out o be the first record of the species from the large protected area of Kedarnath Wildlife sanctuary.

The presence of the invasive plant can have serious impact to the Himalayan forests considering the invasive nature of the plant, says the research correspondence.

"Temperature tolerance level of some alien species is very wide, with global warming the temperature fluctuation has become wide giving these species ample scope to survive", says Jahangeer A. Bhat, Researcher in Forest Ecology at  H.N.B Garhwal University.

According to him, there is no clue on how this plant reached to this elevation. "We guess it might be  through some food source or something else", he said.

"There was no human settlement near this plant patch and neither we found this species below this elevation nor above this elevation. these plants were only present in a patch at the reported altitude", said the research team which found the plant.

Jahangeer A. Bhat, Munesh Kumar, Ajeet K. Negi and N. P. Todaria at the Department of Forestry and Natural Resources, HNB Garhwal University, Srinagar-Garhwal have reported the species, as per the correspondence published.

The plant is already declared as an invasive species in the Indian Himalayan region, while it is reported as a problem species in Portugal, northwest Spain, New Zealand, France and Italy where it is found to be replacing native plant species and taking a high toll on the biodiversity of indigenous plants.

Plants of Acacia genus have been notorious for their ability to invade native forests and replace grass lands. They are also found to increase water loss in riparian zones and thus gradually change the ecological nature of the area.

However, it is ironic that social forestry wings of many state forest departments were once encouraging planting Acacia plants in public places as part of aforestation attempts. The adverse consequences of the plant like its potential to drain up groundwater tables and to produce allergic pollens during flowering season were understood later only.

However, India is still to have a unified central policy on how to manage invasive species in its native forests.

Is there any invasive species raising threat to native plants or animals in your area? Please share us the information here.

Meanwhile, read more on IBT's coverage on invasive species in India.

8 best practices to eliminate weeds in Conservation Agriculture method

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Conservation agriculture is a new method of agriculture which avoids the conventional methods of tilling the land before sowing the seed. Instead, it focuses on minimal soil disturbance and retention of residue to keep the moisture of the soil and to avoid erosion of manure and herbicides.

Maize under Conservation Agriculture in Malawi
Photo courtesy CIMMYT

 However, a major issue with the method is the presence of weeds. Following are some of the best practices to avoid weeds in conservation agriculture. However, they are modified to meet sustainable agricultural practices.

The methods avoid chemical herbicides as they cause environment pollution and turn less effective in long term.

1. Prevent weeds

·         Prevention is always better than herbicides. So make sure that you use clean crop seeds and machinery for seeding, harvesting and threshing, since many weed seeds actually reaches the seed bed in this way.

·         Keep field margins and irrigation canals free from weeds.

2. Stale seedbed techniques

·         Irrigate the seedbed lightly in advance so that the weed seeds which are often found in the soil surface germinate in two three days. Once they germinate in this period, first clear them off manually or using organic herbicides.

·         It is also advised to encourage seed predator insects or birds in the seed bed before sawing.

3. Adjust time of crop sowing

·         Make the crop sowing early in the season so that the crop gets a competitive edge over late germinating weeds.

·         This method has been proved successful in North India against certain weeds like Phalaris minor (Red Rice) when wheat crop was sowed early in the season.

4. Grow a cover crop which gives thick mulch

·         Grow crops like cowpea or sun hemp, which will produce thicker residue, between two main crops. Then cut down it before the main crop season.

·         The dead mulch of the cover crop not only helps retaining the moisture of the farm land, it also suppresses the weed germination by releasing allelo-chemicals and blocking sunlight which is needed for the seeds to germinate.

5. Use of narrow row spacing

·         Place crop rows closer so that they grow thicker, often blocking the sunlight to the space in between two rows, thus decreasing the chances of weed growth in between two consecutive crop rows.

Ground nuts under Conservation Agriculture
Photo courtesy CIMMYT

·         The space between two rows is a vulnerability of the conventional method which actually helps weeds, especially in maize and soya bean cultivation. Narrowing the gap between two consecutive rows can control weeds to a great extent.

·         15 centimeter row spacing is found very successful against P.minor.

·         Long term adoption of the method will bring down the availability of viable weed seeds in a seed bed.

6. Higher seeding rates

·         Increased crop density sometimes helps the crops compete better against weeds.

·         Higher seeding rate is proved to help in weedy or partially weedy seedbeds, though the method may not bring good yield in weed-free environments.

7. Use of weed competitive cultivar

·         The wild or traditional seed varieties which produce long shoot plants are more weed competitive though their yield is not on par with the short stature, high yielding modern seeds.

·         A continuous use of conventional weed-competitive cultivars coupled with narrow row spacing and other methods will bring down the weed presence and number of available weed seeds in a seed bed considerably if the farmers are ready to afford the decrease in production during a short term.

8. Adopting crop rotation

·         Crop rotation helps decrease certain crop specific weeds like P. minor in the case of rice or wheat crops.

·         Rotating the rice crop with a non-rice crop like maize or soybean can disrupt the lifecycle of such weeds.

·         Rotation the management practices also disrupts weed life cycle.

·         Crop rotation improves the soil quality too.

These methods are proved as effective weed management methods in conservation agriculture practices. Many of them are effective in other types of agriculture practices too. However, anyone of these methods when practiced alone may not bring a good result in eliminating weeds. But a brilliant coupling of different methods will surely produce a good result.

If you know any other weed management methods, share it for our readers in the comments.

Reference:
 Chauhan, B. S. & Mahajan, G (2012), Role of integrated weed management strategies in sustaining conservation agriculture systems, Current Science Journal, Volume 103, Issue 2, July 25, 2012, Indian Academy of Sciences, Bangalore, Retrieved from http://www.currentscience.ac.in/Volumes/103/02/0135.pdf on July 25, 2012.

African catfish, Clarias gariepinus – a major threat to native fish species in Western Ghats Rivers

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African Mushi, that is what the farmers in Kerala called that beefy fish, which guaranteed profit for meager investment and care. It ate anything from wastes from slaughter houses and was able to live in any type of water qualities. Moreover, the fish grew faster and bulkier. Within months, a harvest will fetch you kilograms of fish meat from an average fish pond.

Clarias gariepinus

But the after effects were horrid. Recent research reports indicate that the fish has started appearing in fish catches from rivers and lakes in Kerala. Multiple reports suggest that this fish is now commonly caught by fishermen in the lower reaches of Periyar River in Kerala, which is known to house fresh water fresh species only found in Western Ghats Rivers.  Similar reports also indicate that the fish is present in the commercial catches from the Periyar Lake also.  

The writing on the wall is clear. The fish has escaped from fish farms which were connected to natural water bodies and have proliferated in the Western Ghats Rivers and other water bodies in the area. The species is known to devour and sweep away native fish species and other aquatic organisms locally.

The issue is not restricted to rivers in Kerala. It is reported that this invasive fish has also reached the Indrayani River in the southern Deccan Plateau eco-region. It presently raises serious threat to the only existing population of rare Sisorid catfish Glyptothorax poonaensis found in India. Sisorid catfish is listed as endangered by IUCN.

According to IUCN, the southernmost region of the Western Ghats Rivers house more endemic and lesser known fishes in the region. Unfortunately, the devouring African Cat fish has infected the same parts.

Abundance of Globally Threatened fish species 

in Western Ghats Rivers. It can be seen that they are 

more found in the Southern region.

Experts have also expressed concern over the impact of the presence of this African catfishes on lesser known subterranean fishes in Western Ghats. Ichthyologists were able to record just six to seven species from these enigmatic fishes which live in a subsurface ecosystem found under the laterite foot hills of Western Ghats. The chances of the African Cat fish eliminating many of these enigmatic creatures even before the researchers are able to spot and record them are not rare.

There is an urgent need to restrict the aquarium trade and unregulated fish farming. Educating buyers and farmers as well as formulating a proper policy for the management of invasive species are exigencies in this regard. 

Presence of Invasive Species in Western Ghats Rivers: A Major threat

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Western Ghats is the catchment area of 3 large rivers, 13 medium and 17 minor rivers which play a crucial role in the rich biodiversity of the region and the prosperity of some 105 million people living in the area. However, these blood lines of the region are under threat mainly from the burgeoning anthropogenic factors in the name of development and flawed policies.

Abundance of Globally Threatened fish species in the Western Ghats Rivers

According to an in-depth study report submitted to the Western Ghats Ecology Expert Panel about major threats to the riverine ecosystem in the region, dams, mining, tourism, pollution, flawed agriculture practices and deforestation of the riparian cover (forest patches along the river banks) are causing visible degradation to the riverine ecosystems in this World Heritage site. However, K. A. Subramanian who made the study also includes the presence of alien species in the riverine ecosystems in the region as another threat.

Alien species, despite their name, do not come from another planet, but are introduced from non-native ecosystems often for agricultural purposes, as ornamental organisms or even as biological controllers. IUCN has identified introduction of invasive as one of the possible reason for the population decline of native organisms.

Invasive Plant Species in Western Ghats Rivers

Many of the aquatic invasive species in streams and water bodies in the Western Ghats like Salvinia molesta, Pistia stratiotes, Eichhornia crassipes, Hydrilla and Ipomea fistulosa were first introduced as ornamental plants in aquariums. They later found their ways to the water bodies, now spreading to almost all rivers in the Western Ghats.

The changes in the flow pattern and excessive pollution have also helped in the spread of these weeds, especially in catchments which are reeling under the pressure of populated areas. By spreading over the water, they clog the flow of the stream and increase the rate of sedimentation. They cover the water surface, often without allowing the sunlight to pass through, eventually wiping away the submerged species of plants by blocking their chances of photosynthesis.

Mikania macarantha – a Green Threat to the Riparian Biodiversity

Mikania macarantha, is a similar weed which raises serious threat to other plant species in the streams and riparian ecosystem of the rivers in the Western Ghats. This plant forms a thick layer over the stream and the associated riparian forest blocking the sunlight. 

Mikania macarantha, an invasive plant in WG rivers

It is often observed that the invasion of the Mikania macarantha is closely connected to the presence of degraded riparian forest patches in the course of the stream. For instance, in many places like Agasthyarmalai and Anamali region, the weed has been observed as first colonizing streams using degraded shores in estates and forestry plantations, gradually invading into the healthy riparian cover in the adjacent forest areas in the upstream gradually degrading them over a period f time.

Exotic fishes: friend- turned foes?

Exotic fishes are another destructive species which is raising serious threat to native organisms in the Western Ghats Rivers. Introduced for aquarium trade, fish farming and as biological controllers, they have invaded the rivers spreading all over the river network in the area.

Gambusia affinis was widely used as a biological agent to check the growth of mosquitos. However, their introduction to water bodies in the region paved their way to reaching Western Ghats wide river ecosystems. The species have now reportedly colonized many hill streams, especially in parts of Maharashtra. Though they don’t eat up each and every native species like some other invasive species do, they raise fierce competition for resources with native species, often wiping them away locally.

Clarias gariepinus

Clarias gariepinus, the notorious African catfish pet named African Mushi among fish farmers in Kerala and neighboring states, has made a bad example of bringing in foreign species for increased production.

According to an IUCN report on threats on fish diversity in Western Ghats Rivers, Cyprinus carpio, Oncorhyncus mykiss, Pangasianodon hypophthalmus, Oreochromis niloticus, O. mossambicus, Osphronemus goramy, Pterygoplichthys multiradiatus, Piaractus brachypomus, Trichopodus trichopterus, Xiphophorus maculatus, Poecilia reticulata and Gambusia affinis are listed as major invasive threats.

Among these, C. carpio, O. mykiss, G. affinis and O. mossambicus are listed among the top hundred worst invasice alien species database. According to IUCN, these dangerous species are more present in the Southernregion of the Western Ghats where the endemism is highest compared to other areas.

Absence of a national policy for managing invasive species

According to the report submitted to the Convention on Protection of Wetlands, Government of India admits that presence of invasive species has been raising serious threat to the conserved areas in the country. The document also admits that there is no management policy or guidelines issued in this direction. But the government should take immediate actions to make a management policy to check more invasive species reaching to the pristine ecosystems and degrading them gradually.