Linnaökoloogia: uued ökosüsteemid, uued väljakutsed

A Thesis for applying for the degree of Doctor of Philosophy in Applied Biology.Väitekiri filosoofiadoktori kraadi taotlemiseks rakendusbioloogia erialal.The present thesis is the result of four years of PhD studies where various taxonomic groups were explored in terms of taxonomic and functional diversity in urban ecosystems at a broad scale. My research was conducted within the framework of BioVeins, a European research project aimed at studying urban biodiversity of several taxa and ecosystem functions and services in European urban areas. Three out of four European residents currently live in cities, and projections foresee a further increase of city dwellers in the upcoming years (UN, 2019). Urban areas are a patchwork of different land use and land cover types where surfaces unsuitable for most species (e.g. industrial and residential areas) occur simultaneously with green areas (e.g. parks, cemeteries ) varying in size and isolation from other similar areas (Faeth et al., 2012). Urbanization process comes along with land use change, habitat fragmentation and other stressors that compromise biodiversity creating novel ecosystems with new species assembl ages (Gaston, 2010 ; Swan et al., 2011). Therefore, functional diversity, providing the multifaceted ecosystem services and benefits in urban communities depends on biotic and abiotic factors acting as filters of the preexistent traits Spasojevic et al., 2018), and those arriving by natural processes such as dispersal. Novel urban communities composition are guided by processes such as stochasticity, facilitation, competition or adaptation (Kondratyeva et al., 2020). which species assemble The mechanisms by in urban ecosystems may differ from those in natural and semi ecosystems (Masonnatural rural et al., 2011), and are still not fully understood, mainly due to more factors acting in urban community composition compared to rural environments (e.g. social p references, economic constraints, urban heat island effect). Urban green spaces (UGSs) are often seen as potential biodiversity hotspots compared to the surrounding area, as they constitute habitat for native and nonnative species, and provide food and s helter for migrating wildlife (University of California, 2014; Derbi Lewis et al., 2016 ), creating ecological oases in the middle of the impervious surfaces and built structures of the urban fabric. Therefore, while urbanization and urban expansion pose a major threat for biodiversity outside cities, UGSs increase habitat heterogeneity and create new opportunities for maintaining and increasing biodiversity. However, which factors and how they influence urban taxonomic and trait diversity, species compositi on and distribution is not fully understood in urban ecology. In this thesis we firstly propose a research agenda where we discuss five potential research directions aimed at improving our understanding of the links between biodiversity, ecosystem functions and services (BEF/ES) in urban areas. Then, we explore the taxonomic and functional diversity of vegetation, lichens and wild bee species and how they respond to main urban abiotic factors (e.g. landscape metrics, air pollution) and availability of food resources. We selected a wide range of UGSs from seven cities across a NESW gradient of mainland Europe, namely: Tartu (Estonia), Poznan (Poland), Antwerp (Belgium), Paris (France), Zurich (Switzerland), Lisbon and Almada (Portugal). In each city, we selected sites based on the land cover class 1.4.1. Green Urban Areas included in the panEuropean Urban Atlas (EEA, 2012). We used random stratified 2 sampling for the selection of sites. We included the UGS size (area in m connectivity ) and calculated its with other similar elements of the urban fabric by using the Proximity Index (PI) within a 5km radius from the focal UGS. Then we created a matrix formed by two orthogonal gradients comprising the size and the resulting connectivity both classified into 6 classes and distributed the UGSs along the matrix, resulting in a maximum of 36 possible combinations of UGS size and connectivity in each studied city. We sampled taxonomic and functional diversity of woody vegetation, lichens and floral resources us ed by wild bee species using a standardized sampling design framework, thus getting comparable data from the same UGSs across the continental gradient. BioVeins research agenda identified five main research directions, namely: i) use a trait in order to improve our understanding of B-- based approac h EF/ES relationships; ii) improve urban habitat mapping; iii) use citizen science to involve city dwellers in BEF/ES research; iv) consider multiple environmental gradients; and v) include neglected urban habita ecology research. ts and ecological niches in urban In the course of fieldwork (from 2018 to 2020) we identified 418 woody species in 225 UGSs, 140 lichen species in 219 UGSs both across 7 cities, and pollen from 135 plant species as part of the larval bee diet in 80 sites from 5 cities. Regarding urban vegetation, we found high proportions of nonnative woody species in all the sampled cities (i.e. from 40 to 65% of the total species pool). Species richness, vegetative aboveground biomass (AGB) and canopy cover (m UGS size, while species density steeply decreased along the size gradient. 2 ) were positively related to Urban vegetation, particularly herb and tree species, represent an important food source for wild bees and their larvae in cities. Urban bee species displayed different successful feeding strategies. Specialist bee species showed more consistent diets across cities (i.e. less variation in the diet along the latitudinal gradient) compared to more polylectic (generalist) bees. Diet composition in terms of taxonomic and preferred plant traits varied with the specialization degree. Most generalist species showed a more diverse and variable diet, with a higher proportion of exotic plant species compared to more oligolectic (specialist) bee species. The probability of occurrence of medium and high specialized bees decreased with increasing urban intensity. Regarding lichen biodiversity, Lisbon, Antwerp and Tartu showed higher diversity and abundance compared to the other cities. Cities also present ed dissimilarities in terms of functional structure of isplayed a medium or medium lichen communities, with some exceptions. For instance, solar radiation tolerance was high across all the cities (accounting for >75% of the total lichen abundance). In general, more abundant lichens dhigh tolerance to arid conditions. Broad scale environmental drivers (air pollution and climate) explained ~15% of the total variation in taxonomic and trait for urban lichens. The remaining variance (~85%) is exrelated metrics plained by local factors (e.g. distance to the pollution source, management practices, etc.). Within the broad scale drivers, air pollution accounted for most of the variability on that scale (10.4%). However, climate was the driver of lichen functional diversity at the broad scale, although it only explained 7.1% of the broad scale variance. While biodiversity loss is occurring at an unprecedented rate (Leclère et al., 2020), and urbanization increasing globally (UN, 2019), it becomes necessary to integrate biodiversity conservation strategies into urban planning. For this, we need to understand B order to promote multifunctional urban ecosystems.EF/ES relationships at multitaxa level in UGSs are commonly vegetatively diverse environments with heterogen eity of habitats that provide a variety of food and shelter for urban taxa, such as wild bees and lichens. This high species richness is due to the big proportion of nonnative mental purposes) species that are commonly guided by local socio rather than by natural processes (e.g. dispersal). economic preferences (e.g. orna Plant selection and, therefore, species composition have an influence on several urban taxa. For instance, non native plant species turned to be an important component of the larval bee herbaceous and tree species were the preferred plant growth forms diet, and with different levels of diet conservatism across cities at the plant family and genus levels. Our results suggest that while municipalities tend to promote woody species richness, especially in bigger parks, they do so up to a certain threshold, that is city-- dependent. Therefore, local anthropogenic factors play an important role in designing urban biodiversity (e.g. Matos et al., 2019; Munzi et al., 2007) and ecosystem services. However, broad scale drivers also need to be considered since they account for an important proportion in taxonomic and functional diversity of several taxonomic groups (e.g. lichens). Woody species density, lichen diversity and larval bee diet composition revealed good indicators of how decisionmakers integrate biodiversity in urban planning and management. Comparable multi patterns and the taxa and multi relationshipcity studies provide a holistic understanding of urban biodiversity with ecosystem functioning and services. The presented taxonomic and functional diversity of urban green spaces at the contine ntal scale can support the planning and management of urban ecosystems to promote biodiversity and ESs (e.g. pollination, air quality improvement) and, therefore, increase cities resilience and livability for both humans and nature.Käesoleva doktoritöö fookuses oli linnaökosüsteemide taksonoomiline ja funktsionaalne mitmekesisus Euroopa skaalal. Doktoritöös esitatud tulemuste aluseks oli H2020 uurimisprojekt BioVeins (20172020), mille raames uuriti seitsme Euroopa linna rohealade ökosüsteemide funktsionaalsust ja liigirikkust erinevatel elustikurühmadel, alates taimedest, lõpetades putukatega. Praegusel ajal elab juba ligikaudu kolmveerand Euroopa elanikest linnades, ning nende osakaal on lähiaastatel suurenemas (UN, 2019). Linnad on väga heterogeense ja fragmenteerunud maakasutusega piirkonnad, mis on valdavale osale elusloodusest elamiskõlbmatu (tööstussamas leidub linnades erineva suuruse j ja suurelamurajoonid), ent a ühenduvusega alasid (pargid, surnuaiad), mis võivad olla küllaltki elurikkamad (Faeth et al. 2012). Linnastumise käigus leiavad ühest küljest aset maakasutuse muutused, elupaikade killustumine, ja muud elustikule stressi tekitavad protsessid, kuid teises t küljest võivad selle käigus tekkida ka täiesti uued ökosüsteemid, kus samas koosluses elavad liigid, kes looduses kunagi omavahel kokku ei satu (Gaston, 2010; Swan et al., 2011). Linnas leiduvaid rohealasid nähakse sageli linna ümbritsevate aladega võrreldes liigirikkamatena, kuna seal leidub nii looduslikult levinud liike kui ka tulnukliike (Derbi Lewis et al., 2016), olles sel moel ökoloogilisteks oaasideks üldjuhul läbitungimatute pindade ja tehisstruktuuridega kaetud linnaruumis. Seega sõltub linnaökosüsteemide funktsionaalsus, mis pakub linnaelanikele väga erinevaid ökosüsteemiteenuseid ja hüvesid, väga suuresti varieeruda võivatest abiootilistest ja biootilistest teguritest, millede mõju avaldub linnaplaneerimise ja selle kujunemise käigus (Spasojevic et al., 2018). Samuti mängib linnaökosüsteemides väga suurt rolli levimine, mis on oluliselt suuremas sõltuvuses maastikulisest mustritest, kui looduslikes tingimustes; ent olulised, ja looduslike ökosüsteemidega võrreldes nihestatutena, on ka hõlbustamine, konkurents ja kohastumine (Kondratyeva et al., 2020). Lisaks sellele on linnades leiduvad ökosüsteemid sageli suurel määral inimese kujundatud leiduvad liikide kogumid erinevad sageli suurel määral linna ümbritsevate looduslike ja agraarsete piirkondade kooslustest (Mason et al., 2011). Seega võib eeldada, et linnaloodus funktsioneerib paljuski teistmoodi, ja teistest rõhuasetustest lähtuvalt, kui linnasid ümbritsev loodus –– seal kuid meie senised teadmised linnalooduse funktsioneerimisest on väga piiratud. Millised liigid, nende tunnused, ning liikide omavahelised interaktsioonid on linnalooduses olulised, ja kui suurel määral erinev see looduslikes keskkondadega võrreldes, ning millised on nende erinevuste geograafilised ulatused? Käesolevas doktoritöös esitatakse esmalt linnalooduse ökoloogilise uurimise raamistik (I), kus arutletakse viie võimaliku uurimisfookuse üle, mille abil oleks võimalik suurel määral täiendada teadmisi linnalooduse elurikkuse, funktsionaalsuse ja ökosüsteemiteenuste kohta. Seejärel rakendame seda raamistikku uurides seitsme Euroopa linna rohealade taimkatte (II), samblike (III) ja mesilaste (IV) taksonoomilist ja funktsionaalset mitmekesisust, ning neid mõjutavaid inimasustustihedusest suunatud tegureid, nagu heterogeensus ja fragmentatsioon, õhusaaste, looduslike ressursside maht linnaruumis jms. Uurimisaladeks olid erineva suuruse ja ühenduvusega rohealad seitsmes Euroopa linnas: Tartus (Eesti). Poznanis (Poola), Antwerpenis (Belgia), Pariisis (Prantsusmaa), Zürichis ( Šveits), Lissabonis ja Almadas (Portugal). Igas mainitud linnas sai valitud Euroopa Linnaatlasest (European Urban Atlas; EEA, 2012) maakatte klassi “1.4.1 Green Urban Areas” kuuluvad rohealad. Nende seast valisime stratifitseeritud juhuvaliku alusel välja uurimisalad, kuni 36 ala igast linnast. Alade valikul lähtusime kahest parameetrist: roheala suurus ja selle ühenduvus teiste ümberkaudsete rohealadega. Viimase puhul arvutasime välja rohealade võrgustiku 5 km raadiuses iga uuritava roheala ümber. Kõik algsesse alade valikusse jõudnud rohealad jaotati kuude suuruse ja ühenduvuse klassi, ning nende põhjal valiti välja kuni 36 ala, mis jagunesid kõikide suuruse ja ühenduvuse klassi kombinatsioonidesse. (Kahes linnas, Tartus ja Almadas, oli valitud alade number pisut väiksem, kuna mõnesse kombinatsiooni kuuluvaid rohealasid linnas ei leidunud. Seejärel rakendasime iga linna kõikides sõelale jäänud rohealades sama metoodikat uurimaks taimede, samblike ja mesilaste taksonoomilist ja funktsionaalset mitmekesisust. BioVeinsi projekti linnalooduse ökoloogilise uurimise raamistiku (I) käigus tuvastasime viis kõige olulisemat uurimisfookust, mille abil saaks kõige tõhusamalt täiendada teadmisi linnalooduse elurikkusest, funktsionaalsusest ja ökosüsteemiteenustest: i) rakendada linnalooduse uurimisel rohkem funktsionaalsete tunnuste põhist lähenemist: ii) parendada elupaikade kaardistamist linnades; iii) rakendada linnalooduse uurimisel rohkem kodanikuteadust ja hobiteadlasi; iv) kasutada analüüsides üheaegselt rohkem kui ühte gradient; ja v) kaasata linnalooduse ökoloogilisse uurimisse ka mahajäetud alad ja tühermaad, kus leidub omajagu spetsiifilisi nišše. Ajavahemikul 2018 kuni 2020 toimunud välitööde käigus tuvastasime uuritud kokku 418 puittaimeliiki (7 linna 225 rohealal), 140 samblikuliiki (7 linna 219 rohealal) ja 135 taimeliigi õietolmu nelja mesilaseliigi vastse toiduvalikus (5 linna 80 rohealal). Linna rohealade taimkattes leidus väga suurel määral võõr- ja tulnukliike 40% kuni 65% linnade liigifondist. Liigirikkus, maapealne taimne biomass ja puittaimede võra katvus olid enamikes linnades küll positiivselt seotud rohealade pindalaga, ent puittaimede liigitihedus oli tugevas negatiivses seoses rohealade pindalaga kõikides linnades (II). Samblike elurikkuse j a ohtruse näitajad olid kõige kõrgemad Lissabonis, Antwerpenis ja Tartus (III). Kuid samblikukoosluste funktsionaalsus oli linnade võrdluses küllaltki sarnane. Näiteks kiirgustaluvuse poolest olid kõikides linnades väga sarnased samblikukooslused igas linnas moodustasid kiirgust taluvad liigid rohkem kui 75% samblike ohtrusest; samuti olid kõikides linnades enim levinud samblikud valdavalt põuatundlikud. Siiski seletasid samblike taksonoomilist ja funktsionaalset varieeruvust peamiselt lokaalse tasandi faktorid (~85% varieeruvusest), ning regionaalse ja globaalse skaala faktorite (õhusaaste ja kliima suureskaalalised gradiendid) mõju oli pigem väike (~15%). Linnades leiduvad rohttaimed, aga ka puittaimed, on toiduallikaks linnas elavatele mesilastele, eriti nende vastsetele. Uurides nelja Euroopas laialt levinud mesilase vastsete toitumist taimede õietolmust viies linnas (IV) leidsime, et nende toitumisstrateegiad on küllalt erinevad. Spetsialistidest mesilasliikide toidutaimede eelistused olid kõikides uuritud linnades palju sarnasemad kui generalistist mesilasliikidel. Kui spetsialistliikide vastsed toitusid kõikides uuritud linnades samade taimetaksonite õietolmust, siis generalistide toiduvalik oli palju mitmekesisem ja varieeruvam, ning tulnuk- ja võõrliikide õietolmu osakaal oli toiduvalikud oluliselt suurem kui spetsialistliikidel. Mida suurema asustustihedusega linn, seda väiksema tõenäosusega seal spetsialistidest mesilasliike leidus. Ajal, mil elurikkus hävib pretsedenditu kiirusega ( Leclère et al., 2020) ja linnastumine aina kiireneb kõikjal maailmas (UN, 2019) on viimane aeg hakata linnaplaneerimisel ja linnade toimimise analüüsimisel arvesse võtma elurikkust ja ökoloogiat. Tänu linnalooduse eripäradele killustatus ja väiksem ühenduvus, uued ökosüsteemid ja liikide komplektid suurem ei saa me rakendada olemasolevaid analoogseid teadmisi looduslikest süsteemidest, vaid peame neid spetsiifiliselt linnaökosüsteemides uurima, seejuures lähenedes linnaloodusele paljutahuliselt, hõlmates üheaegselt nii erinevaid elustikurühmi, nii nende liigilist kui funktsionaalset mitmekesisust arvesse võttes, kui ka nende pakutavaid ökosüsteemiteenuseid ja hüvesid. Linnades leiduvad rohealad on enamasti küllalt mitmekesise taimestikuga ning väga heterogeensed, pakkudes seeläbi nii ressursse kui ka pelgupaika väga erinevatele elusolenditele, nii sessiilsetele kui mobiilsetele. Paraku moodustavad valdava osa sellest taimestiku mitmekesisusest võõrliigid, mis on haljastuse käigus sinna taotluslikult kasvama pandud, kusjuures istutatavate taimeliikide valikut ei määra liikide ökoloogilised ja bioloogilised omadused, vaid peaasjalikult sotsioökonoomilised faktorid (hind, ornamentaalsus jms). Linna rohealadel kultiveeritavate taimeliikide valik ja neist moodustatavad taimekooslused mängivad väga suurt rolli teiste linnas elavate organismide elus. Käesoleva doktoritöö tulemustest selgub, et linna rohealade planeerimisel kasutatakse haljastuses küll erinevaid puittaimeliike, kuid seda vaid teatud piirini, kaugeltki rohealade ökoloogilisi potentsiaalse realiseerimata. Sestap mõjutavad linnade rohealade elurikkust ja funktsioneerimist peamiselt kohaliku tasandi antropogeensed tegurid (nt Matos et al., 2019; Munzi et al., 2007). Terviklikumat pilti looduslikest protsessides linnaökosüsteemides, linnalooduse lõimituses väga arvesse ei võeta, ning linna rohealade planeerimise läbimõelduse kohta annavad head aimu teised linnades elavad organismid ja nende funktsionaalsus samblikekooslustest kuni linnas elavate mesilasliikide vastsete toiduvalikuni. alates rohealade Uurides linna rohealasid üheaegselt paljude eri tüüpi organismide seisukohast, korraga paljudes erineva vanuse ja asustustihedusega linnades, on võimalik terviklikumalt mõista linnalooduse elurikkust, selle mustreid ja seoseid linnaökosüsteemide toimimise ja nende pakutavate ökosüsteemiteenustega. Käesolevas doktoritöös esitatud analüüsid eri organismirühmade taksonoomilisest ja funktsionaalsest mitmekesisusest seitsmes Euroopa linnas annab hea ülevaate linnalooduse ökoloogilisest seisundist kontinentaalsel skaalal. Esitatud analüüside põhjal on võimalik ka tõhusamalt suunata kohalikul tasandil aset leidvat linna rohealade planeerimist ja haldamist, nii et selle käigus arvestataks ja soodustataks elurikkust ja ökosüsteemiteenuseid linnaökosüsteemides. Loodust ja looduslikke protsesse ka linnaökosüsteemides rohkem arvestades ja arvesse võttes on võimalik muuta linnasid jätkusuutlikumateks elukeskkondadeks nii inimeste endi kui ka teiste linnades elevate elusorganismide jaoks.Publication of this thesis is supported by the Estonian University of Life Scieces and by the Doctoral School of Earth Sciences and Ecology created under the auspices of the European Social Fund

Mapping and assessment of ecosystems and their services. Urban ecosystems

Action 5 of the EU Biodiversity Strategy to 2020 requires member states to Map and Assess the state of Ecosystems and their Services (MAES). This report provides guidance for mapping and assessment of urban ecosystems. The MAES urban pilot is a collaboration between the European Commission, the European Environment Agency, volunteering Member States and cities, and stakeholders. Its ultimate goal is to deliver a knowledge base for policy and management of urban ecosystems by analysing urban green infrastructure, condition of urban ecosystems and ecosystem services. This report presents guidance for mapping urban ecosystems and includes an indicator framework to assess the condition of urban ecosystems and urban ecosystem services. The scientific framework of mapping and assessment is designed to support in particular urban planning policy and policy on green infrastructure at urban, metropolitan and regional scales. The results are based on the following different sources of information: a literature survey of 54 scientific articles, an online-survey (on urban ecosystems, related policies and planning instruments and with participation of 42 cities), ten case studies (Portugal: Cascais, Oeiras, Lisbon; Italy: Padua, Trento, Rome; The Netherlands: Utrecht; Poland: Poznań; Spain: Barcelona; Norway: Oslo), and a two-day expert workshop. The case studies constituted the core of the MAES urban pilot. They provided real examples and applications of how mapping and assessment can be organized to support policy; on top, they provided the necessary expertise to select a set of final indicators for condition and ecosystem services. Urban ecosystems or cities are defined here as socio-ecological systems which are composed of green infrastructure and built infrastructure. Urban green infrastructure (GI) is understood in this report as the multi-functional network of urban green spaces situated within the boundary of the urban ecosystem. Urban green spaces are the structural components of urban GI. This study has shown that there is a large scope for urban ecosystem assessments. Firstly, urban policies increasingly use urban green infrastructure and nature-based solutions in their planning process. Secondly, an increasing amount of data at multiple spatial scales is becoming available to support these policies, to provide a baseline, and to compare or benchmark cities with respect to the extent and management of the urban ecosystem. Concrete examples are given on how to delineate urban ecosystems, how to choose an appropriate spatial scale, and how to map urban ecosystems based on a combination of national or European datasets (including Urban Atlas) and locally collected information (e.g., location of trees). Also examples of typologies for urban green spaces are presented. This report presents an indicator framework which is composed of indicators to assess for urban ecosystem condition and for urban ecosystem services. These are the result of a rigorous selection process and ensure consistent mapping and assessment across Europe. The MAES urban pilot will continue with work on the interface between research and policy. The framework presented in this report needs to be tested and validated across Europe, e.g. on its applicability at city scale, on how far the methodology for measuring ecosystem condition and ecosystem service delivery in urban areas can be used to assess urban green infrastructure and nature-based solutions

The magnetic signal from trunk bark of urban trees catches the variation in particulate matter exposure within and across six European cities

Biomagnetic monitoring increasingly is applied to assess particulate matter (PM) concentrations, mainly using plant leaves sampled in small geographical area and from a limited number of species. Here, the potential of magnetic analysis of urban tree trunk bark to discriminate between PM exposure levels was evaluated and bark magnetic variation was investigated at different spatial scales. Trunk bark was sampled from 684 urban trees of 39 genera in 173 urban green areas across six European cities. Samples were analysed magnetically for the Saturation isothermal remanent magnetisation (SIRM). The bark SIRM reflected well the PM exposure level at city and local scale, as the bark SIRM (i) differed between the cities in accordance with the mean atmospheric PM concentrations and (ii) increased with the cover of roads and industrial area around the trees. Furthermore, with increasing tree circumferences, the SIRM values increased, as a reflection of a tree age effect related to PM accumulation over time. Moreover, bark SIRM was higher at the side of the trunk facing the prevailing wind direction. Significant relationships between SIRM of different genera validate the possibility to combine bark SIRM from different genera to improve sampling resolution and coverage in biomagnetic studies. Thus, the SIRM signal of trunk bark from urban trees is a reliable proxy for atmospheric coarse to fine PM exposure in areas dominated by one PM source, as long as variation caused by genus, circumference and trunk side is taken into account.info:eu-repo/semantics/acceptedVersio

Ecosystem mapping for the implementation of the European biodiversity strategy at the national level. The case of Italy

Several international initiatives, including the European Biodiversity Strategy to 2020, promote the identification and mapping of ecosystems as basic tools for the conservation of biodiversity and related services. On coarse scales, the spatial representation of ecosystems is usually based on broad land cover categories that largely overlook important ecological and biogeographic features of the biotic communities they are meant to exemplify. This paper presents a nationwide ecosystem mapping approach that promotes a degree of thematic detail, which is more suited than that found in the continental maps to meeting biodiversity conservation targets in Italy. The approach is based on the rationale that current and potential vegetation cover are valuable proxies for outlining ecosystems. The resulting Ecosystem Map of Italy includes 43 types of forest ecosystems instead of the 5 woodland, forest and other wooded land types recognized at the European level. We outline the expected advantages of this enhanced thematic detail for a number of conservation purposes and highlight how the resulting maps may help to meet biodiversity conservation targets at the national level. In particular, we refer to the assessment of conservation status, the definition of restoration priorities, the planning of green infrastructure and the identification of collapse risks for the ecosystems identified. Comprehensively, the definition, characterization and assessment of ecosystem types represent the carrying structure of the recently launched national system of natural capital accounting

Research agenda on biodiversity and ecosystem functions and services in European cities

Cities are challenging environments for human life, because of multiple environmental issues driven by urbanization. These can sometimes be mitigated through ecosystem services provided by different functions supported by biodiversity. However, biodiversity in cities is affected by numerous factors, namely habitat loss, degradation, and fragmentation, as well as pollution, altered climate, and new biotic challenges. To better understand the link between biodiversity and ecosystem functions and services, we need to improve our mechanistic knowledge of these relationships. Trait-based ecology is a promising approach for unravelling the causes and consequences of biodiversity filtering on ecosystem processes and underlying services, but large gaps remain unexplored. Here, we present a series of research directions that are aimed at extending the current knowledge of the relationship between trait-based biodiversity and ecosystem functions and services in cities. These directions are based on: (1) improving urban habitat mapping; (2) considering often neglected urban habitats and ecological niches; (3) integrating multiple urban gradients; (4) using trait-based approaches to improve our mechanistic understanding of the relationships between biodiversity and ecosystem functions and services; and (5) extending the involvement of citizens. Pursuing these research directions may support the sustainable management of urban ecosystems and the long-term provision of ecosystem services, ultimately enhancing the well-being of urban populations.(C) 2021 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved

How do urban green space designs shape avian communities? Testing the area-heterogeneity trade-off

Abstract: In cities, green areas are essential for biodiversity conservation, with land cover heterogeneity being a decisive factor. Yet, as heterogeneity increases for a given green area, the patch size of land covers automatically decreases, as the area available for individual species, especially habitat specialist species. This relationship, known as the area-heterogeneity trade-off, is expected to lead to a unimodal relationship between species richness and land cover heterogeneity, and contrasted effects between species according to their level of urban avoidance. We investigated the potential consequences of this trade-off on birds in green areas selected along an urban intensity gradient in six European cities. Using a European database on bird occurrences in nesting habitats, we defined a continuous gradient of urban avian avoidance. We confirmed the marked area-heterogeneity trade-off in urban green areas but found no effect of land cover heterogeneity on total avian richness at green area level. However, both land cover heterogeneity and patch size were positively associated with richness of urban avoider species, indicating that urban avoiders fared better in green areas with large and heterogeneous patches. Total richness was also higher in green areas surrounded by an urban matrix composed of a variety of land covers. To protect urban bird avoiders, which are most at risk in cities, green area managers and urban planners should thus be aware that land cover heterogeneity is not a panacea if patch sizes are too small. To conserve avian richness, we stress the importance of maintaining large vegetated areas as well as heterogeneity in land covers within the urban matrix