Invasive Alien Species- Challenges to Biodiversity and Conse

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National Workshop on Invasive Alien Species Biodiversity in India , Department of Botany, Banaras Hindu University, Varanasi, August 18 th -20 th , 2004, Invasive Alien Species- Challenges to Biodiversity and Conservation By Vinod Khanna Zoological Survey of India, Northern Regional Station, 218, Kaulagarh Road , Dehra Dun-248 195 (Uttaranchal) India

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Think of an invasion, and the picture that comes to our mind is usually that of planes and tanks, machines and men, shells and gunshots. But animal and plant species also run amok, especially when they enter an ecosystem where they did not exist previously. After habitat destruction, the invasive alien species are biggest threat to the world biodiversity.

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“ Invasive Species “ is defined as A species which is on-native (or Alien) to the ecosystem and whose introduction in a new ecological territory causes or is likely to cause economic or environmental harm, or harm to human health . Or alternately The Invasive Alien Species are those that produce fertile offsprings in large numbers at a considerable distance from their original ecosystem , compete with native species , destabilize the ecosystem, cause economical loss and get naturalized over there .

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Generally the movement of plants and animals across habitats and ecosystem is a natural process ecosystems are inherently dynamic, losing some species, gaining others it is the constantly accelerating rate of invasion that looms large over the world economy today. Human actions are the primary means of invasive species introductions . The invasive species generally have dramatic and negative effect on the other species and even entire ecosystem to the extent that it includes the extinction of species or sometimes even the hydrology and nutrition cycles of entire ecosystems have changed.

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The Impact of Invasion is second only to that of human population growth and associated activities as they cause 1. Loss of Biodiversity 2.Decline of Native Species (Endemics). 3.Habitat Loss 4. Introduced pathogens Reduce crop and stock yields , besides 5 .Degradation of marine and freshwater ecosystems This biological invasion constitutes the greatest threat to biodiversity, and it has already had devastating consequences for the planet and challenges for the conservation managers

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Warnings All the invasive species are not harmful and it would not be possible even to quantify the damage done nor to exactly know the quantum of invasion unless the total biodiversity of any area is worked out and enough documentation is available to prove the species as invader. Much of the invasive species may be lost to the habitat loss or become extinct before estimated biodiversity is deciphered.

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Invasion and Species Richness ? Over 120,000 non-native species of plants, animals and microbes have invaded just six countries- the US, UK, Australia, South Africa, Brazil and India (David Pimental of College of Agriculture and Life Sciences, Cornell University, Brazil and India. The invasions potentially lead to an increase in species richness , as invasive species are added to the existing species pool . BUT also leads to extinction of native species , resulting in decrease of species richness . The negative interactions is primarily the competition with natives for food and sustenance, which may not allow coexistence .

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Ecology of Invasion requires addressing of three criteria. While Natural Invasions are very slow the transport and trade are the primary cause for quick invasiveness. The rate and mechanism of transport or movement of organisms . 2. The characteristics of the organisms that allow them to be successful invaders and 3. The properties of ecosystems that make them susceptible or resident to the invaders.

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Ballast Water Shipping Transport is t he most common mode of invasions by marine species. In order to provide stability to vessels, the ships when they contain little or no cargo traveling from deep-sea waters to shallow seas,carry the Ballast water. And when the ship returns back to deep waters the ballast is released, thereby bringing a lot of marine micro-organisms, microbes, protozoan, zooplanktons, phytoplankton, diatoms etc.,along with and releasing them in other geographical territories. It is principal medium responsible for transporting more than 4,000 of alien organisms daily .

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The Other Methods are: By-product of human commerce : Translocated in packaging material, timber, produce, soil, and plants. Introduced for biological control Road vehicles : Translocated in packaging material, timber, produce, soil, plants. Wind: Movement of winged queens. Agriculture (local): Deliberate spread by agricultural officials . Imported/ Exported for Ornamental value of the species Self-propelled dispersal (local): Probably once established, natural spread is the main means of spread. Species Introduced for sports fishing Introduced for food value . A weed of pasture and plantation Nursery Trade Horticulture Invasion of species associated with Fruit Export/Import

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Basic patterns of invasions and invasibility are: The high susceptibility of island communities to invasion by mainland species , with subsequent extinction of island endemics and replacement by mainland species. The dominance of the earth’s largest landmass, Eurasia, as a primary source of successful invaders throughout the rest of the world and Relatively low proportion of successful invaders in Eurasia in comparison with the rest of the world . (Eurasian species have had far greater opportunities to disperse throughout because of the pre-eminence of Europe as a center of exploration and trade. However, the trade and transport are a two way process, with the return of trade goods, raw material and agriculture products, probably containing as much invaders from other regions as have been dispersed out of Europe. The interpretation that Eurasian species tend to be better competitors than other organisms from other continents is consistent with both prehistoric and historical patterns of extinction and invasion).

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Organisms in relation to Invasions : The introduction or invasion of a species in alien area is a first step yet not necessarily most critical. All introduced species are not successful invaders. There should be some relationship between the biological properties of the invading species and the properties of ecosystem that it invades. The damage by Invasives is both ecological and economic. It’s a challenge to the world, to the biodiversity, to the endemics and to the biodiversity conservation .

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The Islands face the highest risk of the Impact of Invasiveness . Not all types of ecosystem are equally susceptible to being invaded. Part of the resistance of some ecosystems to invasion is clearly a function of the competitive ability and other ecological properties of the species already present . The Island Species have a poor competitive ability than the mainland species and generally have a smaller variety and total amount of resources (e.g., plant seeds, insects) than do the mainlands , the Island Species may tend to be generalized to use a broader range of resources than the mainland species and thus are unlikely to have the high efficacy that results from specialization on particular resources It is thus a paradise for mainland species to invade Islands and eradicate the natives. The native Island species are at risk .

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Economic Loss (US $ million) Introduced Pests US India Weeds Crops 27.9 37.8 Pastures 6.0 0.92 Vertebrates Crops 1.0 - Arthropods Crops 15.9 16.8 Forests 2.1 - Plant Path Crops 23.5 35.5 Forests 2.1 - Total 78.5 91.02 Source: David Pimental et al.,2001. Economic and environmental threats of alien Plant, animal and microbe invasions, Ecosystems and Environment, 84

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Species in the US and India Category United States India __________________________________________ Total Alien Total Alien ________________________________________________________ Plants 42,000 25,000 45,000 18,000 Mammals 346 20 390 30 Birds 650 97 1,221 4 Reptiles and 247 53 741 NA Amphibians Fishes (Freshwater) 938 138 2,546 300 Arthropods 650,000 4,500 54,430 1,100 Microbes 134,644 20,000 NA NA Source: David Pimental et al.,2001. Economic and environmental threats of alien Plant, animal and microbe invasions, Ecosystems and Environment

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Species enters dispersal pathways 10 % Established as Casual Species 10 %Species survives dispersal and Is introduced into a habitat What it takes to be invasive? 10% Spread INVASIVE 90%Naturalized 90% fails to disperse 90% fails to establish Source: Suresh Babu et .al, 2003 A successful invasion is a rare event. An accepted thumb rule is that only 10% introduced species become naturalized, and only one in 10 among the latter actually turn invasive because a species arriving in a new community faces a series of filters, like

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Environmental filters of the natural Habitat Geographical Filters >100 kms Environmental Barriers in Invaded Habitats Local and regional dispersal barriers Reproductive Barriers Natural Barriers filtering Species Invasions Environmental filters in managed habitat Non-native Casual Naturalized Invasive Source: Suresh Babu et .al, 2003

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The animals species should have very high fecundity rate even in unfavorable conditions High compatibility to survive in the Alien Ecosystem High genetic viability Strong potential to compete with other native species . Requirements of Animal Species to become a successful Invader

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Requirements of a Plant Species to become a successful Invader 1. It has long-lived seeds for discontinuous germination 2. It grows rapidly from vegetative to reproductive stage 3. It is capable of very high seed output when environmental conditions are favorable. 4 . It produces seeds continuously throughout the growth period and in range of environmental conditions. 5. It is built to disperse seeds over short and long distances. 6. It has a strong potential to compete with other species .

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Ecological paradox But the ecological paradox is that, 1. Usually even if a species is present in small numbers, its breeding options are low. This genetic bottleneck might cause it to become extinct. But invasive species manage the bottle neck with flourish, and after establishment can explode in numbers. 2.Some species may be intrinsically better competitors because they evolved in a more competitive environment and the 3.Lastly, the absence of enemies like herbivores in case of plants-gives the non-indigenous species more resource to grow, reproduce and eventually out-compete the native species .

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Naturalized Invasive Species : Once established and naturalized detection and prevention of invasive species becomes next to impossible. The only hope is to control contamination, or completely eliminate the threat. Options to control spreads are limited. Though weeds can easily be mechanically removed but it rarely works, as in case of Lantana or introduced deers in Andaman and Nicobar Islands in 1915. Even controlled fire does not work for many weeds. Indeed, the effect is often a fire-cleared field, now made ready for invasive to take over.

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Aspects needed to be studied about the Invaders Category, whether plant, animal ( aquatic or land) Area of Invasion , whether, Agriculture land, wetlands ( fresh water or marine) Originl habitat of Invasion Reasons for dispersal ( Accidental, Human interface, experimental or sudden out break) Impacts on natives, habitats, ecosystem, crops, food, elimination of natives by competing for food Geographical range of the species Invasion pathways ( Like , Agriculture : Translocated in soil, produce and timber. Aircraft : Transported in packaging material, timber. Military : Transported in road vehicles, machinery, boats, and aircraft. Nursery trade : Transported in soil and produce. Other : Deliberate introductions for biological control of plant pests on coconut, coffee and cacao plantations.

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(Contd.) Road vehicles (long distance) : Transported in soil, packaging materials, pallets. Sea freight (container/bulk) : Transported in goods, packaging, and pallets in container. Local Dispersal Methods : Boat : Translocated in packaging material, timber, produce, soil, and plants. Other (local) : Redistribution for biological control on coconut, coffee, and cacao plantations. Wind : Movement of winged queens. Management Informations: Nutrition Reproductive Mode Reproductive Output: Lifecycle Stages Economic importance of the Invader introduced for biocontrol Economical loss to the invaded ecosystem Extent of degradation brought about to the invaded ecosystem Loss to biodiversity Threat to endemics. Species effected or likely to be effected. Challenges to the conservation managers etc. etc. Aspects needed to be studied about the Invaders

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The Criminal Invasive Alien Species in India Some Case Studies:

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List of species in the Global Invasive Species Database :

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Examples of Marine Invasive Species Introduced via the Shipping Industry

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List of Invasive Reptilian Species

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Wanted ? More Predictive Research : To manage invasive, one has to predict where it will attack. Globally, relevant ecological and climatic data, and computational abilities to process such huge data sets, have evolved recently . In India, such forecasting is rare.

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Invasive Alien Species and the Legislations : No law on this seems to exist , at present in India. On lines with the International Plant Protection Convention , India is formulating regulations that prevent the introduction and spread of plants and plant products, based on the phytosanitary certificates between the countries. It aims at quarantine control, risk analysis and other measures to prevent the establishment and spread of all alien invasive species. The International Marine Organisations suggests methods of managing Ballast Water to prevent marine invasions. The Cartagena Protocol , a supplementary agreement to Convention on Biodiversity, seeks to protect biological diversity from potential risks posed by living modified organisms resulting from modern biotechnology. It establishes an ‘advance informed agreement’ procedure to ensure that countries have information necessary to make informed decisions before agreeing to import of modified organisms. Under the new regulations, import of germ plasm, transgenic or genetically modified organisms will be overseen by the National Beaureu of Plant Genetic Resource.

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Conclusions : 1. Invading species are identified as being indigenous to regions other than the area being invaded, there is essentially no biological difference between the process of invasion and the process of colonisation or recolonisation of areas by native plants. 2.Interspecific competition and other interactions ultimately regulate community structure and species diversity in natural communities. They also regulate the success and failure of invading species. 3. The life histories of the invaders are strongly constrained by the frequency of disturbance. 4. Most serious effects of invading plants occur when they alter the environment they invade. 5. Endemism and invasions represent ecological phenomena at extremes of several contexts of evolutionary and ecological process. The environmental conditions that allow the evolution and survival of endemic species, namely low rates of competitive displacement and low frequency of major disturbances, also allow high diversity plant communities with many endemic species to be easily invaded by exotic species. 6. Fortunately the same conditions also prevent the invading species from dominating the community and reducing species diversity unless the invasion is accompanied by a change in the disturbance regime of the community.

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7. Ecosystems in productive environments are quite resistant to invasion under natural conditions of low disturbance frequencies. The properties of the species that influence their ability to resist invasion or survive in the presence of exotic species of competitors or predators are largely the result of their evolutionary history. 8.The vulnerability of island species to extinction caused by competition or by predation by introduced predators is responsible for most of the extinctions that have occurred as a result of phenomenal increase in the transport and dispersal of species by human activities. 9.There are numerous natural and ecological filters that the invasive species has to pass through before the species is naturalized . Once established and naturalized detection and prevention of invasive species becomes next to impossible. The only hope is to control contamination, or completely eliminate the threat. Options to control spreads are limited. Though weeds can easily be mechanically removed but it rarely works, as in case of Lantana. Even controlled fire does not work for many weeds. Indeed, the effect is often a fire-cleared field, now made ready for invasive to take over.

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The Phenomenon of Invasion is a great challenge to Biodiversity, Endemics, Ecosystems, Conservation and Conservation Managers. It involves complex, multiple aspect and multi-disciplinary studies with follow ups. Thank you Dr.Vinod Khanna, Zoological Survey of India, Dehra dun