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Geospatial Health 2019; volume 14:727 Assessment of the health impact of paper mulberry (Broussonetia papyrifera L.), an invasive plant species in Islamabad, Pakistan Sana Qazi, Javed Iqbal, Junaid Aziz Khan Institute of Geographical Information Systems, School of Civil and Environmental Engineering, National University of Sciences and Technology, Islamabad, Pakistan revealed an increasing trend of paper mulberry density towards the Abstract southern and south-western part of Islamabad. Although not evident This study focuses on the risk of pollen allergy due to paper during rainfall, a clear positive correlation was found between mulberry (Broussonetia papyrifera L.), an Asian invasive plant patient count and pollen count. Field survey data and hotspot spatial species now common in large parts of the world. Pollen plays a key analysis of allergy patients revealed that residents of Shakerperiyan role in the pathogenesis of respiratory allergic diseases, particularly and Lok Virsa areas (Sectors H-8, I-8, I-9, G-8, G-7 and G-6 in rhinitis and asthma, and Islamabad, a major metropolitan city, is Islamabad) had more pronounced symptoms compared to residents severely affected by allergy owing to B. papyrifera pollen. Due to of other sectors. The methodology adopted used in this study can be its seasonality and other relationships with climatic variables, we used to map the distribution of similar invasive species in other used remote sensing to monitor the trend of pollen count. We also parts of the country. mapped the localisation of patients affected by pollen allergy using only geographic information systems. The maximum likelihood algo- rithm was applied to SPOT-5 satellite imagery for land use/land cover classification. Temporal analysis of remotely sensed data Introductionuse Pollen released from different plants is a key aeroallergen in the pathogenesis of respiratory allergic diseases, i.e. rhinitis (Bousquet et al., 2003) and asthma (Wu et al., 2011). The male Correspondence: Junaid Aziz Khan, Institute of Geographical plant of paper mulberry (Broussonetia papyrifera L.) produces an Information Systems, School of Civil and Environmental Engineering, inflorescence called toot or catkin and its pollen is regarded one of National University of Sciences and Technology, Room 201, IGIS the most clinically relevant aeroallergens investigated (Micheal et Building, NUST, Sector – H-12, Islamabad, Pakistan. al., 2013). The pollen situation is aggravated by the rapid growth Tel. +92.51.90854494. and invasive nature of alien species triggered by the homogenisa- E-mail: [email protected] tion of the world’s flora and fauna (Mooney and Hobbs, 2000). As invasive plants have a tendency to replace native vegetation Acknowledgments: the authors would like to show their gratitude to the (Stohlgren et al., 2001; Pauchard and Alaback, 2004), they repre- National Institute of Health (NIH) and Pakistan Institute of Medical Sciences (PIMS) for sharing the data of allergic patients with us which sents a threat for forests and agricultural lands globally. Paper made this research possible. mulberry is identified as an invasive species in twenty-eight states of the United States and reported as a weed in over a dozen coun- Key words: Paper mulberry; Invasive species; Pollen allergy; Remote tries around the world (Malik and Husain, 2006). It is a native sensing; Spatial analysis; Pakistan. plant of China, Japan, Korea, Taiwan, Cambodia, Laos, Myanmar, Thailand, Vietnam, and Malaysia (Csurhes, 2012) and (Malik and Contributions: the authors contributedNon-commercial equally. Husain, 2007) have documented invasion by this plant in the Conflict of interest: the authors declare no potential conflict of interest. Himalayan foothills of Pakistan during the three latest decades. Funding: the research was funded by National University of Sciences The cultivation of alien species of trees, shrubs and herbs, and Technology, Pakistan. imported from distant regions of the world, is an essential compo- nent of urban vegetation (Honu et al., 2009). In the federal capital Received for publication: 25 July 2018. Islamabad, a strategy called the Greenway concept started as early Revision received: 27 October 2019. as in the 1960s to revamp the roads by plantations in an effort to Accepted for publication: 28 October 2019. improve landscape quality (Ali and Malik, 2010). However, this practice affected the diversity of the indigenous vegetation nega- ©Copyright: the Author(s), 2019 tively, and paper mulberry is now the sixth worst plant-invader Licensee PAGEPress, Italy Geospatial Health 2019; 14:727 among the many non-native plant species introduced into doi:10.4081/gh.2019.727 Pakistan, (Khatoon and Ali, 1999, Alien invasive species in Pakistan, University of Karachi, Pakistan. Personal This article is distributed under the terms of the Creative Commons Communication) recognised as a critical factor in the transforma- Attribution Noncommercial License (CC BY-NC 4.0) which permits any tion of the vegetation composition of the area (Ashraf et al., noncommercial use, distribution, and reproduction in any medium, pro- 2012). B. papyrifera tolerates a wide range of climates, including vided the original author(s) and source are credited. humid tropical (monsoon), humid and sub-humid subtropical as well as warm temperate situations. It tends to be most abundant on [page 340] [Geospatial Health 2019; 14:727] Article soils that are generally moist; however, it is also capable of occu- Paper mulberry survey pying drier sites (Malik and Husain, 2007) as it can survive a 3-4 A total of 100 sampling points of paper mulberry and 50 sam- months dry season (Whistler and Elevitch, 2006). Conventionally, pling points of other plant species were recorded with a handheld invasive plant species removal is carried out, using the method Garmin eTrex Vista HCx global positioning system. The control described by Flory and Clay (2009), i.e. weeding by hand, spray- points found were further divided into two equal subgroups with ing with both post-emergent and pre-emergent herbicides. half of them used as training samples for supervised classification Each B. papyrifera catkins yield approximately 150-200 inflo- and the other half used for validation of a land use/land cover map. rescences, each capable of releasing 3 to 6 million pollen grains The maximum likelihood classifier was used for imagery classifi- into the atmosphere during the spring season (Galán et al., 1991). cation. In the period February-April, proximity to this plant contributes to severe pollen allergy in many parts of Pakistan (Ali and Malik, Patient data 2010). Pollen counts during this period reaches approx. 40,000/m³ The relationship between the pollen count and the number of (Haroon and Rasul, 2008) in some places causing severe asthma- patients was analysed. Data regarding patients affected by pollen related problems in the local population. Pollen allergy occurs in allergy were collected from the Institute of Medical Sciences Islamabad and most parts of North Western Punjab, Hazara, (PIMS) hospital and at the National Institute of Health (NIH) in Lahore, Karachi and Central Pakistan (Sadiq and Qureshi, 2010). Islamabad. Due to lack of spatial location information of the data The World Allergy Organization once stated that 41.9% of allergy provided by hospitals, a field survey was conducted from 10 to 15 patients in Islamabad are suffering from pollen allergy due to paper December 2013 mapping all residencies of interest. Random aller- mulberry pollen (Abbas et al., 2009) and this situation has not gy patient data were recorded in different sectors of Islamabad to improved. In Islamabad, the B. papyrifera pollen count can be very 3 get first-hand information regarding pollen allergy severity and high, some days reaching above 30,000/m . Most of the residential prevalence of this type of allergy in Islamabad City. The flowchart area of Islamabad is under the threat of this pollen allergy. What is of the methodology of theonly study is depicted in Figure 2. In order to alarming is that its severity level is gradually increasing. This is find the severity level of pollen allergy among the patients, four obvious from the fact that the increasing number of patients with categories were defined, i.e. i) no symptoms, ii) mild symptoms serious respiratory conditions, including asthma that can lead to (sneezing accompanied with clogged or runny nose), iii) severe death due to congestion of the airways. symptoms use(fever and inflammation of the membrane that line the Remote sensing has many attributes beneficial for detecting, eyelids causing red-rimmed eyes), iv) asthma. The patient data mapping and monitoring the invasive plants (Joshi et al., 2004; were also categorised by age to study the impact of pollen with ref- Huang and Asner, 2009). A few attempts made with SPOT-XS data erence to the age of the patients. For this purpose, five age classes have been carried out (Malik and Husain, 2008), but satellite data were defined: 0-18, 19-30, 31-50, 51-60 and >60 years old. The have not been utilised fully for mapping different plant species in total number of patients sampled were 145, out of whom 76 were Pakistan. The potential of satellite data for estimating species rich- females and 69 males. ness is likely to be due to the near-infrared bands, rather than the visible bands, which share highly redundant information Pollen data (Nagendra and Rocchini, 2008; Hofmann et al., 2017). The pollen count data used in the study was obtained from the This study focuses on: i) mapping and monitoring the presence Pakistan Meteorological Department (PMD) along with the other of B. papyrifera L. by means of remote sensing; ii) monitoring meteorological data such as rainfall, humidity, wind speed and pollen count trends and association with climate variables; and iii) wind direction. mapping the localisation of patients affected by pollen allergy using geographic information systems. The overall aim was to con- Satellite data firm the association between areas where pollen is produced in the Remotely sensed data from Landsat 7 (https://landsat.