Anjana Dewanji, Anindita Chatterjee & Achyut Kumar Banerjee. Agricultural & Ecological Research Unit Indian Statistical Institute Kolkata, India

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1 Anjana Dewanji, Anindita Chatterjee & Achyut Kumar Banerjee Agricultural & Ecological Research Unit Indian Statistical Institute Kolkata, India

2 World wide distribution Distribution in India Present scenario in India Establishment or spread? Detecting presence in Kolkata Soil analysis and thematic moisture map Presence of infestation along transport networks Remote sensing and supervised LULC classification Conclusions

Predicted distributions of alligator weed in 1995 Continents / Regions Nature Main Countries EPPO region invasive France, Italy North America invasive Mexico, USA Central America invasive Honduras

Puero Rico Oceania invasive Australia, New Zealand, Indonesia, Papua New Guinea Legends Areas of circles are proportional to the suitability of the location for the weed.

3 Predicted distributions of alligator weed in 1995 Continents / Regions Nature Main Countries EPPO region invasive France, Italy North America invasive Mexico, USA Central America invasive Honduras South America native Argentina, Bolivia, Brazil, Colombia, Paraguay, Peru, Uruguay, Venezuela Asia invasive China, India, Myanmar, Singapore, Sri Lanka, Taiwan, Thailand, Vietnam Caribbean invasive Puero Rico Oceania invasive Australia, New Zealand, Indonesia, Papua New Guinea Legends Areas of circles are proportional to the suitability of the location for the weed. Hatches are locations with known distributions of the weed Crosses indicate unfavourable locations for growth of the weed Figure Source: Julien MH, Skarratt B and Maywald GF (1995) J. Aquat. Plant Manage 33: 57. Table source: accessed on April 9, 2010

1995 2013 INDIA now INDIA Legends Areas of circles are proportional to the suitability of the location for the weed.

4 INDIA now INDIA Legends Areas of circles are proportional to the suitability of the location for the weed. Hatches are locations with known distributions of the weed Crosses indicate unfavorable locations for growth of the weed Reported presence in India

6 Total no. of reports on Alternanthera philoxeroides in India

7 Figures: Alternanthera philoxeroides growing at local sites

8 STUDY SITE: Kolkata Metropolitan Area or Greater Kolkata Lat-Long: 88º 30'E - 22º 33' N. Population: One of the most densely populated cities of world INDIA STUDY AREA:1, km 2 24,000/sq km within the city and 9,000/sq km in suburbs STUDY DURATION: 3 months -4 th Jan, 2012 to 5 th Mar, 2012 KOLKATA West Bengal

9 Greater Kolkata map Map georeferencing Map Digitisation 5kmx5km grid generation Centroid generation

Clay Silt Sand Soil sampling WATER HOLDING CAPACITY (WHC) MOISTURE

10 Gridded Map with Centroids Field survey to 78 centroid points Alternanthera presence (53)/absence (25) recorded Soil Analysis TEXTURE Clay Silt Sand Soil sampling WATER HOLDING CAPACITY (WHC) MOISTURE Observations: 70 % sites had moderate infestations Terrestrial sites (25) Aquatic sites (28)

Soil Parameters Mean ±SD Clay (%) 24.62±11.05 Silt (%) 24.87±9.01 Total Sand (%) 50.49±16.8 Water Holding Capacity (%) 54.

89 Figure: Box plots of Clay, Silt and Total Sand percent in soil with Alternanthera infestation; values indicate medians

11 Soil Parameters Mean ±SD Clay (%) 24.62±11.05 Silt (%) 24.87±9.01 Total Sand (%) 50.49±16.8 Water Holding Capacity (%) ±8.99 Moisture (%) ±15.89 Figure: Box plots of Clay, Silt and Total Sand percent in soil with Alternanthera infestation; values indicate medians Inference: Terrestrial infestation of Alternanthera show preference for sandy loam soils soils with more than 50% WHC and soils with atleast 30% moisture content. Figure: Different soil textural class with Alternanthera infestation

categorized into 2 habitats:- Aquatic & Terrestrial Soil analysis for the terrestrial

12 Remote Sensing GIS LISS III image LULC Classification Accuracy assessment C. Thematic classified map generation Field survey at centroid points Plant infestation categorized into 2 habitats:- Aquatic & Terrestrial Soil analysis for the terrestrial Alternanthera infestation Georeferenced map A. Transport map generation B. Soil moisture thematic map generation

Based on soil moisture percent, 10 equal

growth of terrestrial plant Large areas (brown)

13 Based on soil moisture percent, 10 equal classes were generated Vernoi polygon was used to create thematic map Observations: Inference: Soil moisture of atleast 25 to 30% suitable for growth of terrestrial plant Large areas (brown) present in the study area denoting potential for spread

Observations: Inference: More than 60% of presence for

14 Major and minor roads digitized on map using Google earth image as reference and points imported Observations: Inference: More than 60% of presence for both types along major roads showing disturbance to be an important factor

15 Satellite image used: LISS (Linear Imaging Self Scanning Sensor) III Satellite IRS P6 (ResourceSat 1) Sensor LISS III Approach to Classification: Spectral band Spectral coverage (nm) Spatial resolution (m) Radiometric resolution (bits) Swath width (km) 141 Band Band Band Band Some training areas were marked on the image to identify LULC classes Spectral separability analysis between classes were checked usingtransformed Divergence value for all band combinations Band ratio 3:4 (Red: Infrared) found most suitable for classifying image Supervised classification using Maximum Likelihood algorithm overall accuracy 94.23% Satellite image Class Producer s accuracy User s accuracy Deep water 98.96% 100% Shallow water 99.40% 99.86% LISS III Dense vegetation 92.14% 81.46% Sparse vegetation 85.15% 94.28% Built up land 97.64% 95.47% Barren land 99.5% 77.52%

16 Inference Aquatic infestations mostly correctly classified Terrestrial infestations occurred around built up land and sparse vegetation (species poor habitats) Both these areas are maximally present in the study area again showing concern for spread!!

17 Reported presence of Alternanthera philoxeroides increasing over years Results indicate high potential for spread in urban areas Infestations are more prone near major roads re emphasizing disturbance to be an important factor associated with spread. Terrestrial infestations occur in areas with sparse vegetation as well as around built up land a common aftermath of urbanization! Mapping important for creation of baseline data and monitoring spread to sound an early warning for intervention if needed.

18 Thank you!

Developing a global, peoplebased definition of cities and settlements

Developing a global, peoplebased definition of cities and settlements By Lewis Dijkstra, Lewis.Dijkstra@ec.europa.eu Head of the Economic Analysis Sector DG for Regional and Urban Policy, Regional & Urban