to develop concrete adaptive measures for the urban settlements for the long term (Kattel et al. 2013; Steiner 2014). Thus, for sustainable cities, novel solutions and techniques for landscape planning having the potential of resilience and self‐regulation from the extreme climatic conditions are needed (Childers et al. 2015; Yu et al. 2017). In this regard, urban vegetation can play a major role by managing the energy/radiation balance of the physical environment through the process of photosynthesis, evapotranspiration, and shadowing effects (Oke 2002; Yu et al. 2017). Moreover, Steiner (2014) highlighted four potential urban ecological design/planning measures, viz. application of ecosystem services, adaption of settlements for the natural disasters by managing green infrastructures, renewal of degraded landscapes, and improving the adaptive behaviour of people by linking knowledge about the surroundings to the actions.
The thematic evolution showed that there is a transitional shift in research focus during the last two decades (Figure 1.2). It can be seen that for the 2005–2014 period, social (climate change, urbanisation, and rural gradients) and ecological (phenology, conservation, vegetation, and UHI effect) aspects hold almost equal importance which get diversified in different emerging ecological aspects like ecology, ecosystem services, communities, resilience, and water during the 2015–2021 period. The 2015–2021 period showed the convergence of climate change and urbanisation, and conservation, whereas diversification of vegetation and conservation into communities, ecosystem services, ecology, and resilience showed that more research emphasis has now been given on ecosystem resilience and self‐sustaining systems for the climate change mitigation. Moreover, the role of spatial modelling tools such as remote sensing and geographic information system (GIS) for developing sustainable urban ecosystems by vegetation mapping and risk analysis by the extreme weather events (climate change) has also been evolving considerably. Moreover, the role of vegetation phenology and its impact on various ecosystem services under the changing climatic conditions is also getting wider attention. The challenges to the urban ecosystems and adaptation strategies for the climate change have been briefly illustrated in Figure 1.3. In the next few sub‐sections, ecosystem services and green infrastructure‐related aspects have been elaborated while less emphasis has been given on later two mitigation measures in this chapter.
Figure 1.2 Thematic evolution of the urban ecology and climate change research areas during the last two decades.
Source: Data from Web of Science Core Collection database (2021).
Figure 1.3 Illustrative representation of the challenges of the urban ecosystems and climate change adaptation strategies.
1.5.1 Ecosystem Services
Ecosystem health represents the system resilience, organisation, and vigour for the sustainable functioning (Costanza 1992). Ecosystem services are the major components of ecosystem health which not only provide benefits to the humankind but also help in regulating the overall functioning of an ecosystem (Verma et al. 2020b). For example, urban and peri‐urban forests help the urban society to tackle many of the issues such as protection from heat waves, flood/stormwater, pollution, etc. related to their livelihood (Green et al. 2016; Livesley et al. 2016). A few major ecosystem services (provisioning, supporting, cultural, and regulatory) provided by the urban vegetation include the temperature mitigation (urban cooling), noise level reduction, air purification, climate mitigation, nutrient cycling, C‐sequestration, pollination, providing food (garden and farms), recreation opportunities, ecotourism, run‐off mitigation, waste decomposition and detoxification, habitat for biodiversity, etc. (Steiner 2014; Dallimer et al. 2016; Aronson et al. 2017; Richards et al. 2019; Pedersen Zari 2019). Enumeration of ecosystem services of the urban ecosystems can be done by basic mapping to the valuation and management (McDonald and Marcotullio 2011). However, the extent of ecosystem services demanded by and provided to the urban dwellers varies from city to city throughout the world (Lososová et al. 2018; Richards et al. 2019). Moreover, an increase in extreme weather events has been reported to disrupt the provisioning of ecosystem services, causing an emerging challenge for finding appropriate adaptation measures (Wamsler et al. 2013). Site‐specific enumeration of ecology and climate conditions may help in developing ecosystem services‐based urban regeneration strategies (Pedersen Zari 2019). The ecosystem services are needed to be included in the major policy and decision‐making agendas related to the urban planning and designing in the changing climate scenarios (Pedersen Zari 2019). Thus, with the growth of urban population and climate change, finding the appropriate methods for improving the provisioning of ecosystem services is needed (Richards et al. 2019). Moreover, research on evaluating ecosystem services in the urban ecosystems from the tropical regions is also needed to be explored.
1.5.2 Plant Adaptations
Not all the species are sensitive to the higher temperature and drought conditions, as some of the species may escape these extreme conditions by developing resilience and adaptations. In a study on species distribution under varying ranges of the European regions, Lososová et al. (2018) reported that about 45% of species do not show any direct relationship with the geographical distribution and climatic conditions. Thus, with the ongoing climate change, several species have been expected to decline, whereas some other species (particularly alien) which showed resilience to the climate change may spread, particularly in the European urban ecosystems. In other words, the space/niches created due to the decline of a species would be filled up by those species which have the tendency to cope‐up with the increased temperature and drought conditions (Lososová et al. 2018). The fast‐growing annuals (herbs) respond more quickly to the environmental changes as compared to the perennial herbs and woody vegetation (Grime 2001), thus these species may have wider distribution ranges in the future. The ruderal life strategy, production of large number of seeds/propagules and self‐pollination traits help the annual herbs to track the environmental changes more quickly (Aarssen 1998; Lososová et al. 2018). Therefore, they are considered as the key indicators of the ongoing climate change. Further, the dominance of plants using the C4 photosynthetic pathway has also been reported from the urban regions as compared to the non‐urban regions of the European countries (Duffy and Chown 2016). It is expected that the C4 plant species have more adaptive capacity to the localised warming conditions created by the UHI effects in the European regions which can be a strategy for the shift in future vegetation cover in these regions with the climate change (Duffy and Chown 2016). Such type of studies related to the species composition and climate change adaptation are needed from the tropical regions of the world as well.
1.5.3 Green Infrastructure
Green infrastructure is a strategic approach of landscape and environmental planning based on the principles of landscape and urban ecology (Niemelä 2014; Ramyar and Zarghami 2017). It represents the interconnected network of ecosystem structures such as green spaces (parks and gardens) and water bodies which are designed and managed for delivering numerous ecosystem services (European Commission 2013; Niemelä 2014; Green et al. 2016). These infrastructures are the critical components of the urban areas and provide several benefits to the humans in terms of ecological, environmental, and social challenges (Tzoulas and Greening 2011; Keniger et al. 2013; Ramyar and Zarghami 2017). Moreover, the concept of green infrastructure provides a common platform for scientists and researchers
