Urban Tree Diversity Research Articles

Diversity of urban trees in the city of Villahermosa, Tabasco, Mexico

Diversity of urban trees in the city of Villahermosa, Tabasco, Mexico

Resilient trees for urban environments: The importance of intraspecific variation

Societal Impact StatementTrees in urban environments provide us with shade, heat mitigation, flood abatement, noise and pollution reduction, pollination, beauty, and much more. However, many of these benefits are strongly connected to tree size and vitality, with larger, healthier trees providing ecosystem services more effectively, which means that selecting the right tree for site and function is crucial in order to gain all benefits from our urban trees.SummaryTrees play a major role in the Earth's biogeochemical processes, influencing soil production, hydrological, nutrient and carbon cycles, and the global climate. They store about 50% of the world's terrestrial carbon stocks, and provide habitats for a wide range of other species, supporting at least half of the Earth's known terrestrial plants and animals. Trees are not only found in forests and other natural ecosystems, but also in urban environments. Most of the human population is concentrated in cities, towns and villages, so urban trees are critical to meet on‐going and future social, economic and environmental challenges. However, many urban tree populations are strongly challenged by a changing climate, outbreaks of pests and pathogens and an urban development with increasingly dense cities and a high proportion of impermeable surface materials. The importance of intraspecific variation needs to be better acknowledged in this context, since poor matching of trees and the local climate and growing conditions can lead to extensive loss of valuable trees. By using the right genetic plant material for the challenging urban environments, a more resilient tree population with a greater diversity and higher capacity for delivering ecosystem services can be gained. Here, we wish to discuss the need to consider intraspecific variation when planning resilient tree populations for urban environments and how seed banks and botanical garden play important roles in efforts to improve the matching of genetic plant material for future environmental challenges. Strategies to enrich urban tree diversity and increase resilience are outlined.

Unveiling the complex networks of urban tree diversity research: A global perspective.

Ecosystem services offered by urban forests must be proactively managed to remain diverse and sustainable. Recent research findings deserve a systematic synthesis to elucidate inherent knowledge structures and dynamics. This study focused on the urban tree diversity theme from 2000 to 2022. Web of Science Core Collection database provided bibliometric details on academic publications. The data-driven quantitative analysis explored research quantities, emphasis, trends, patterns, linkages, and impacts by countries, institutions, authors, journals, and citations. Publications and research topics have expanded continually, with accelerated growth in recent years. Research activities, outputs and interactions demonstrated conspicuous spatial clustering. A few countries, institutions and researchers generated a notable proportion of publications. Their scholarly contributions were visualized in knowledge graphs as complex networks of nodes and inter-node links. Keyword analysis generated a network to indicate research hotspots and frontiers to steer and prioritize future studies. Recent findings affirmed that cities can harbor substantial tree diversity due to enhanced habitat heterogeneity and successful species adaptation. Aligning tree traits with environmental conditions and management objectives can improve benefits. Urbanization can filter tree traits to shape community assemblages through stressors: habitat degradation, fragmentation and loss, in conjunction with pollution, climate change, and introduced species. Diversity preservation strategies include protecting remnant natural vegetation, connecting green spaces, and restoring complex canopy geometry and biomass structure. The emerging frontiers are marked by modeling future species distributions, leveraging technologies like remote sensing, linking ecology with human values, and committing to community-based stewardship. Management can be upgraded by interdisciplinary perspectives integrating ecological science and social engagement. The findings highlight the need for biodiversity enrichment anchored by native species, trait-matched assemblages, adaptive policies, and community participation to create livable-green cities. This review synthesizes key advances in urban tree ecology and biodiversity research to inform the planning and stewardship of resilient urban forests.

An Urban Forest Diversification Software to Improve Resilience to Global Change

Abstract The importance of urban tree diversity for improving resilience is increasingly understood by decision makers. Urban foresters want to prevent the overrepresentation of species on their streets and in their city, which could result in a significant loss of canopy cover in the event of a large-scale disturbance such as a drought or an exotic pest or disease. Although numerous software and tools exist to visualize tree inventories and plan tree maintenance work, only a few offer support for increasing tree diversity. After reviewing the existing tools available for urban forest managers, we present SylvCiT, a novel decision-support and open-source software available on a web platform designed to consolidate information related to the urban forest in one place and facilitate decision-making at different scales. While the first interfaces provide the user with a spatially explicit portrait of the urban forest (species richness, functional diversity, structural diversity, i.e., diameter classes) and associated ecosystem benefits (e.g., stored carbon, ornamental value), the software is designed to produce a list of functional groups and appropriate species to plant considering tree species already present. Based on an artificial intelligence algorithm, SylvCiT identifies the types of trees (species and functional groups) that are absent or underrepresented at different scales to make recommendations that increase species and functional diversity to improve resilience to global change. SylvCiT will continue to be developed to evaluate other ecosystem benefits and integrate criteria such as site characteristics into the recommendation algorithm.

The unexplored effects of artificial selection on urban tree populations.

The unexplored effects of artificial selection on urban tree populations.

Expanding Urban Tree Species Diversity in Florida (USA): Challenges and Opportunities for Practitioners

While many practitioners and scholars understand the risks associated with low urban tree diversity, they often lack the ability to rectify this challenge on their own. The complex system of tree production and procurement is shaped by market pressures, nursery and site constraints, local governance, and differing professional objectives among those who grow, specify, and plant trees. To understand constraints to and opportunities for increasing urban tree diversity, we conducted a series of focus groups comprised of nursery growers, landscape architects, and municipal tree managers. Our results highlight a significant list of considerations and constraints to diversity, with some issues shared among green industries and some specific to growers or purchasers. In light of our findings, we outline actionable strategies for increasing urban tree diversity.

(Re)Designing Urban Parks to Maximize Urban Heat Island Mitigation by Natural Means

Urban trees play a key role in mitigating urban heat by cooling the local environment. However, the cooling benefit that trees can provide is influenced by differences in species traits and site-specific environmental conditions. Fifteen dominant urban tree species in parks from Mexico City were selected considering physiological traits (i.e., transpiration and stomatal conductance) and aesthetic and morphological characteristics. Species’ physiological performance was measured to explore the potential of trees to reduce urban heat load. Data were collected over a 4-week period in the months of April and May 2020, the warmest and driest months of the year in Mexico City. We used the Thermal UrbaN Environment Energy (TUNEE) balance model to calculate the cooling benefit of each species and the number of individuals necessary to reduce local air temperature. The highest midday transpiration was registered for Liquidambar styraciflua L. (0.0357 g m−2 s−1) and the lowest for Buddleja cordata H.B.K (0.0089 g m−2 s−1), representing an energy consumption and cooling potential of 87.13 and 21.69 J m−2 s−1, respectively. Similarly, the highest stomatal conductance was recorded for L. styraciflua., whereas the lowest was recorded for B. cordata. Based on the species transpiration rates and aesthetic characteristics, we developed a proposal and outline for a 50 × 50 m urban park (i.e., park community) consisting of six species with 19 individuals, and according to the TUNEE model, the proposed arrangement can reduce air temperature up to 5.3 °C. Our results can help urban planners to (re)design urban parks to mitigate urban heat while increasing urban tree diversity in parks.

Assessing the species diversity and vulnerability of urban tree populations in the London borough of Westminster

The level of tree species diversity in urban tree populations can have serious implications for urban forest resilience and has a direct impact on ecosystem functioning at the local level. Few studies have measured the relationship between tree species diversity and vulnerability in UK urban forests. This study analysed the species composition, species diversity and the vulnerability to pests and diseases of 10,149 public trees in the London borough of Westminster across three land use types: housing, parks, and highways. Tree species diversity was significantly different across these land use types (Shannon’s diversity index (H) was 2.47 for housing sites, 1.63 for parks and 0.83 for highways) and we found that higher diversity appears to result in reduced vulnerability, evidenced by negative correlations between tree species diversity and susceptibility to pests and diseases. A stronger negative correlation was found between vulnerability and species richness than between vulnerability and Gini-Simpson’s diversity index. Our study reinforces the role of biodiversity indices in establishing and monitoring baseline levels of UK urban tree diversity. Our findings may inform future tree planting projects, help to ensure that development does not negatively affect urban tree diversity and inform proactive strategies for urban trees to contribute to wider biodiversity conservation.

Assessment of the Diversity of Large Tree Species in Rapidly Urbanizing Areas along the Chao Phraya River Rim, Central Thailand

Urban trees provide numerous ecosystem services in cities such as pollution absorption and reduced urban heat island intensity, energy use, and mental fatigue. Understanding urban tree species diversity can enhance tree planning and management in rapidly urbanizing areas. However, few studies have examined the effects of urbanization on urban tree diversity in Thailand. This study assessed the diversity of large trees in urban landscapes including 11 cities along the 372 km Chao Phraya River Rim in central Thailand. Species diversity, importance value, and distribution were evaluated in each city. Our survey documented 987 large trees belonging to 65 species, 48 genera, and 31 families. The dominant species of Dipterocarpus alatus and Hopea odorata had the highest importance and relative abundance. The highest abundance of large trees was seen in the rural city of Sing Buri, while large urban cities such as Ayutthaya and Bangkok exhibited the highest species diversity. Detrended correspondence analysis indicated that the diversity of unique species was high in large urban cities, while dominant and common species were ubiquitous in rural cities. These findings suggest that large trees are few in number but exhibit high species diversity in large rapidly urbanizing cities. Therefore, preserving good site conditions is critical for the survival of large trees in urban cities. Heritage tree registration may aid preservation efforts and enhance the benefits of these large trees in rapidly urbanizing areas.

Mapping the diversity of street tree inventories across eight cities internationally using open data

Tree diversity, on a species-, genus-, and family-level, is an important factor in securing healthy urban forests and providing ecosystem services for billions of city dwellers. Using open-source data on global tree inventories, this study examines (1) the diversity of species, genera, and family of urban street trees in eight cities internationally; (2) how they score on diversity benchmarks and indices; and (3) the diversity variation inside and outside of cities’ centers. We hypothesized most cities would score poorly on diversity benchmarks and spatial patterns in species composition would exist, as illustrated by established relationships between urban density and urban tree diversity. Results indicate city centers were less likely to approach the proposed diversity benchmarks than outside the city center. Overall, both Shannon and Simpson diversity indices show greater diversity outside of the city center, especially at the species-level. Understanding street tree diversity and spatial variation patterns across cities internationally can offer needed evidence to back up heuristic benchmarks. The methodology and open-source data used in this study are intended to enable practitioners better target tree diversity efforts.

Effect of urban tree diversity and condition on surface temperature at the city block scale

Urban forests affect land surface temperature (LST) within a city due to the cooling effect of transpiration. The latter depends on tree health, but it can also be affected by the structure and composition of forest, as a mono-species environment may potentially worsen the health of urban forest. The following hypotheses are therefore proposed: a) greater tree diversity within urban forest results in lower LST at the city block scale; and b) the state of biotic disturbance of urban forest is negatively correlated with LST. The present research explores the relationship between urban forest tree diversity and health based on a survey of 38,950 individuals in the district of Providencia in the city of Santiago, Chile, and compares this information against LST data from the ASTER satellite instrument at the city block scale. The health of the urban forest was determined by expert knowledge means of a field survey that collected data concerning growth stage, phytosanitary state, and state of biotic disturbance. The first hypothesis could not be tested by the lack of urban tree diversity which showed strong domination of three species with more than 52 % of abundance (Robinia pseudoacacia, Platanus orientalis and Acer negundo). The second hypothesis was proved since the results revealed a positive and significant correlation between urban forest diversity and LST, with a Spearman’s correlation coefficient of between 0.56 and 0.7. A positive and significant correlation of 0.55 was found between mean biotic disturbance (BDSm) and median LST (Med), indicating a direct relationship between higher LST and poorer urban forest health. A possible explanation is that, among the trees surveyed within the urban forest, the effect of biotic disturbance is greater than that of species diversity. As such, it may be concluded that planting of trees on city streets as a means of temperature moderation is made less effective if specimens are maintained in a poor general condition of health.

Exploring urban tree diversity and carbon stocks in Zaria Metropolis, North Western Nigeria

Urbanization is a pressing issue of concern especially in Africa where it is expected to continue and increasingly, threaten the efficiency of natural carbon sinks and sustainability of cities. This paper assessed the diversity and carbon storage of trees in Zaria metropolis, North-western Nigeria through fieldwork and allometric equations. A total of 200 assessment plots were randomly generated using Idrisi Terrset software. Quadrats of 30 × 30 m dimension were established and all trees, ≥5 cm diameter were identified and enumerated. Diameter was measured at breast height while tree height was measured with Suunto clinometer. The study recorded 836 stems, belonging to 51 species in 21 families. Species diversity and evenness were considerably high (H’ = 3.30, J = 0.8) with more exotic than native stems. The trees stored 657.05t carbon with the highest proportion contributed by Azadirachta indica, Mangifera indica and Khaya senegalensis. One-way ANOVA revealed significant difference in tree diameter (p < 0.020), basal area (p < 0.008) and height (p < 0.001) across the different land use/cover types but no significant difference in carbon stock (p > 0.657). This study demonstrates the contribution of urban trees in reducing global atmospheric carbon which largely varies with tree species and diameter.

Urban Tree Selection for Diversity

Urban tree diversity is important when attempting to create a healthy, beneficial, and resilient urban forest. Having a variety of trees can increase the aesthetic value for residents and create habitats for plants and animals. Some common street trees currently in the landscape are not site-appropriate and create infrastructure damage. By planting different types of trees in these locations, maintenance costs and infrastructure damage can be reduced and tree longevity increased. This new 4-page fact sheet is intended to provide urban foresters, arborists, landscape designers, and others in charge of tree planting with a process for introducing new species into the urban environment. Written by Deborah R. Hilbert, Andrew K. Koeser, and Robert J. Northrop, and published by the UF/IFAS Environmental Horticulture Department.https://edis.ifas.ufl.edu/ep589

A Tree Selection Survey of Tree City USA Designated Cities in the Pacific Northwest

As urban areas expand, there are a greater number of urban trees; however, development often leads to a reduction in urban trees in many areas. A reduction in the canopy volume of trees results in a reduction in the number of benefits. Additionally, urban trees can have additional stressors and must be more actively managed to maintain those services. Selecting tree species for the right site can lead to greater benefits and longer-lived trees. Increasing diversity of urban trees can help to mitigate some of the threats facing urban forests, such as invasive pests and climate change. We surveyed Tree City USA designated cities across Oregon and Washington to explore how they are selecting tree species for their municipalities. Responses were recorded for 79 out of 151 municipalities for a 52.3% response rate. Both open-ended questions and descriptive statistics were used to triangulate how managers are selecting tree species. Emergent themes in open-ended responses indicate a variety of justifications for tree species selection and the challenges of balancing those criteria. There is evidence to suggest that these municipalities are actively diversifying the urban forest; however, there are still 10 municipalities that reported ash (Fraxinus spp.) in their top 5 most frequently planted species in 2016. Many municipalities are still planting large quantities of maple (Acer spp.). Overplanting certain genera and species can lead to an increase in susceptibility to pests and pathogens. We recommend an increase in consideration for the diversification of tree species in urban areas.

Urban plant diversity in Los Angeles, California: Species and functional type turnover in cultivated landscapes

Societal Impact StatementPeople plant, remove, and manage urban vegetation in cities for varying purposes and to varying extents. The direct manipulation of plants affects the benefits people receive from plants. In synthesizing several studies of urban biodiversity in Los Angeles, we find that cultivated plants differ from those in remnant natural areas. This highlights the importance of studying cultivated plants in cities, which is crucial for the design and planning of sustainable cities. Residents have created a new urban biome in Los Angeles, and this has consequences for associated organisms, ultimately resulting in a responsibility for society to determine what type of biome we wish to create.SummaryUrbanization is a large driver of biodiversity globally. Within cities, urban trees, gardens, and residential yards contribute extensively to plant biodiversity, although the consequences and mechanisms of plant cultivation for biodiversity are uncertain.We used Los Angeles, California, USA as a case study for investigating plant diversity in cultivated areas. We synthesized datasets quantifying the diversity of urban trees, residential yards, and community gardens in Los Angeles, the availability of plants from nurseries, and residents’ attitudes about plant attributes.Cultivated plant diversity was drastically different from remnant natural areas; compared to remnant natural areas, cultivated areas contained more exotic species, more than double the number of plant species, and turnover in plant functional trait distributions. In cultivated areas, most plants were intentionally planted and dominated by exotic species planted for ornamental purposes. Most tree species sampled in Los Angeles were available for sale in local nurseries. Residents’ preferences for specific plant traits were correlated with the trait composition of the plant community, suggesting cultivated plant communities at least partially reflect resident preferences.Our findings demonstrate the importance of cultivated species in a diverse megacity that are driven in part through commercial distribution. The cultivation of plants in Los Angeles greatly increases regional plant biodiversity through changes in species composition and functional trait distributions. The pervasive presence of cultivated species likely has many consequences for residents and the ecosystem services they receive compared with unmanaged or remnant urban areas.

Hunting for a Larger Diversity of Urban Trees in Western Europe—A Case Study from the Southern Caucasus

The primary aim of this study was to communicate a method for locating natural habitats where trees grows under conditions that are comparable to those in urban environments in terms of water stress. This is presented by analyzing five different forest reserves in the southern Caucasus (Republic of Georgia) where calculation of net water balance over the period of a year was conducted. This provided an insight into the drought at the sites during the growing season. The data were thereafter compared with similar calculations for five different cities in Western Europe in order to see if there were any matches in drought stress between the cities and the forest reserves. To extend the analysis, conditions in the five cities were assessed for high density and low density areas, and for the current climate and a future climate scenario. The comparisons revealed some matches between conditions in the forest reserves and those in different scenarios/areas in the cities. A secondary aim was to identify specific ecotypes in the wild demonstrating great potential to handle growing conditions similar to those in urban environments based on inventories of woody plants in the forest reserves. A total of 44 woody species were found in the forest reserve systems with a random distribution throughout the five study sites. Based on the commitments presented above a preliminary screening can be done where future tree selection focus can be directed towards highly promising species and ecotypes, which would undoubtedly limit the time lag before proper plant material can be released.

Comparison of Hyperspectral Techniques for Urban Tree Diversity Classification

This research aims to assess the capabilities of Very High Spatial Resolution (VHSR) hyperspectral satellite data in order to discriminate urban tree diversity. Four dimension reduction methods and two classifiers are tested, using two learning methods and applied with four in situ sample datasets. An airborne HySpex image (408 bands/2 m) was acquired in July 2015 from which prototypal spaceborne hyperspectral images (named HYPXIM) at 4 m and 8 m and a multispectral Sentinel2 image at 10 m have been simulated for the purpose of this study. A comparison is made using these methods and datasets. The influence of dimension reduction methods is assessed on hyperspectral (HySpex and HYPXIM) and Sentinel2 datasets. The influence of conventional classifiers (Support Vector Machine –SVM– and Random Forest –RF–) and learning methods is evaluated on all image datasets (reduced and non-reduced hyperspectral and Sentinel2 datasets). Results show that HYPXIM 4 m and HySpex 2 m reduced by Minimum Noise Fraction (MNF) provide the greatest classification of 14 species using the SVM with an overall accuracy of 78.4% (±1.5) and a kappa index of agreement of 0.7. More generally, the learning methods have a stronger influence than classifiers, or even than dimensional reduction methods, on urban tree diversity classification. Prototypal HYPXIM images appear to present a great compromise (192 spectral bands/4 m resolution) for urban vegetation applications compared to HySpex or Sentinel2 images.

城市乔木树种多样性遥感反演方法研究

PDF HTML阅读 XML下载 导出引用 引用提醒 城市乔木树种多样性遥感反演方法研究 DOI: 10.5846/stxb201808131728 作者: 作者单位: 中国科学院生态环境研究中心城市与区域生态国家重点实验室,中国科学院生态环境研究中心城市与区域生态国家重点实验室,中国科学院生态环境研究中心城市与区域生态国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金重大基金项目（41590841）；国家自然科学基金面上项目（41771203）；中国科学院前沿科学重点研究项目（QYZDB-SSW-DQC034）；科技部国家重点研发计划项目课题（2016YFC0503004） A new approach to mapping tree diversity based on remote sensing imagery Author: Affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences Fund Project: The Key Program of the Chinese Academy of Sciences,省、部研究计划基金 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:量化城市乔木树种多样性是定量研究其生态系统服务的前提和基础。目前，城市树种多样性水平的定量研究以地面调查方法为主，存在效率低、成本高的问题。针对上述问题，首先验证了光谱变异性假说和生产力假说在城市中的适用性，进而提出了快速量化城市树种多样性水平的方法。该方法基于神经网络刻画了乔木斑块多样性与光谱异质性之间的关系，能够较准确地反演城市乔木的香浓维纳指数和辛普森指数。为城市乔木树种多样性的调查提供了新的思路，并将为定量研究城市乔木多样性的生态系统服务提供基础数据。 Abstract:Urban tree diversity is responsible for many ecosystem services. Quantifying the level and spatial pattern of tree diversity is crucial for the assessment of ecosystem services. However, previous quantitative studies on urban tree diversity are mainly based on field surveys, which are highly expensive and restricted by poor efficiency. In this study, we firstly tested the applicability of Spectral Variation Hypothesis (SVH) and Productivity Hypothesis in urban areas. Then, we developed a new approach for quickly and efficiently quantifying tree diversity using remote sensing imagery. This new approach described the relationship between urban tree diversity and spectral heterogeneity based on Neural Network Model, which could be used to calculate the Shannon-Wiener index and the Simpson index of urban trees. This study provides a new direction for studying urban tree diversity, and our results are critical basic data for studying ecosystem services of urban tree diversity. 参考文献 相似文献 引证文献

Genetic diversity loss and homogenization in urban trees: the case of Tilia × europaea in Belgium and the Netherlands

Urban trees form a vital component of sustainable cities but the use of a restricted range of species and genotypes may pose a risk to global biodiversity. Despite several studies investigating tree species diversity, intraspecific genetic diversity of urban trees remains largely unexplored. Here, we characterized the genetic diversity of Tilia × europaea, one of the most widely planted urban tree species in Northwest Europe. We compared the genotypic diversity of historical plantings of Tilia spp. from the 17th century with the genotypic diversity of currently available planting stock in Belgium and the Netherlands. In total, 129 trees were sampled and genotyped with 14 microsatellite loci and 150 polymorphic Amplified Fragment Length Polymorphism markers. In Northwest Europe, homogenization of urban T. × europaea plantings already started at the 17th century. Genetic diversity within contemporary commercial planting stocks was extremely narrow and consisted mainly of two clones, sold under the name ‘Pallida’ and ‘Zwarte linde’. The genetic diversity found within the historical plantings was about four times higher than in the current commercial planting stocks. We recommend that tree nurseries should enlarge the genetic diversity of T. × europaea commercial planting stocks. The old clones have shown long-term disease resistance and could provide tree breeders with the valuable new genetic material. The range of available Tilia species and genotypes needs to be explored in future urban tree planning to optimize desired ecosystem services.

Urban land transformations and its implication on tree abundance distribution and richness in Kumasi, Ghana

Despite the rapid urban transformation in green space in most cities in Ghana, knowledge on urban tree diversity and the evidence of the consequences of built-up expansion on trees is scanty. This article provides a novel contribution to the current urban trees abundance and richness in Kumasi Metropolitan Area, Ghana. Post classification change detection technique was applied to quantify urban land use land cover (LULC) transformations (urban forest, agricultural, riparian vegetation and built-up) from 2007 to 2017. Species rank abundance distribution and richness were quantified using geometric series and individual-based rarefaction models. A total of 858 individual trees belonging to 76 taxa were recorded across the four LULC classes. Species abundance distributions in three LULC types varied substantially, with the exception of riparian LULC (slope [k] 0.08660.12, v2P 19.42, P0.15). Land use pressure led to a 13.56km2 reduction in forest cover, while built-up and agricultural LULC increased by 31.13 and 1.85km2, respectively. These disturbances did not only affect indigenous tree dominance (41.3%) in favour of exotic species (58.7%) in the agricultural and built-up LULC types but also impacted on tree abundance (n126) and richness (n28) in agricultural land compared to abundance (n280) and richness (n67.86) in forest cover. Despite the contribution of LULC transformation to increase in tree diversity, there is the likelihood of future dominance of exotic species in the Metropolis if urban planners do not institute measures to conserve indigenous species.