Dark diversity dynamics linked to global change: taxonomic and functional perspective
Date
2023-04-11
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Abstract
Tume elurikkus – elupaigast puuduvad, kuid sinna sobivad liigid – on oluline mõistmaks, kuidas piirkonna elustik kujuneb. Tume elurikkus on vaadeldud elurikkuse vastaspool, mõlemad koos moodustavad elupaiga liigifondi ehk kõikide sobivate liikide nimekirja. Kuigi on teada, et globaalmuutused mõjutavad eluskooslusi nii ruumis kui ajas, ei ole varem otseselt käsitletud, kuidas tumeda elurikkuse kontseptsioon aitab uurida bioloogilise mitmekesisuse muutuseid antropotseenis ning tõhustada looduskaitset. Oma doktoritöös arendasin teoreetilist raamistikku, kuidas liikide saabumine ja kadumine võib toimuda nii ühe liigifondi piires kui ka nende vahel. Uurides tumeda elurikkuse muutusi tuhandete aastate jooksul sai edukalt eristada taimetaksoneid, mille levila laieneb viivitusega: liigid suudaks muutunud tingimustes elada, kuid on veel pikka aega puudu. Liikide tunnuste analüüs näitas, et holotseeni ajal tumedasse elurikkusesse kuulunud ja seega ka levimisviivitusega taksonid olid omavahel suhteliselt sarnase ehituse ja elukäiguga. Tumeda elurikkuse taksoneid iseloomustas kiire elustrateegia (madal levimissvõime ja stressitaluvus). Lisaks leidsin, et tumedat elurikkust ja liikide omadusi saab kasutada keskkonnatundlike organismide (nt samblike) looduskaitse tõhustamisel, selgitades, millised liigid ja tunnused on väljasuremisohus ja milliseid saaks kasutada taastamises. Kokkuvõtteks, tume elurikkus on rakendatav erinevate taksonoomiliste rühmade, ajaperioodide ja globaalmuutuste tegurite korral, näitamaks, kui palju, kui kiiresti ja mis suunas muutuvad vaadeldud elurikkus ja liigifond. Tumeda elurikkuse kontseptsioon on seega paljutõotav lähenemine bioloogilise mitmekesisuse uurimiseks muutuvas maailmas.
Dark diversity - the set of suitable but locally absent species - is an important concept to understand how ecological communities are assembled from regional to local scales. Dark diversity is the counterpart of observed diversity, which together form site-specific species pool. However, given that global change drivers affect community assembly processes across space and time, prior to this thesis no studies had explored how dark diversity could be useful to examine biodiversity dynamics in Anthropocene. Dark diversity may improve how we quantify and assess biodiversity change, and, consequently, enhance nature conservation. In this thesis, I advanced the role of dark diversity as a tool to examine biodiversity change by developing a conceptual framework in which species gains and losses are decomposed within and between species pools, revealing different biodiversity flows with possible time lags. Over millennial temporal scales, the dark diversity concept successfully depicted plant taxa facing expansion lags in their geographic range; species becoming suitable for changed environments but remaining absent. Functional traits revealed that taxa persisting in dark diversity over the Holocene and, thereby, in expansion lags, were those displaying high functional redundancy, and fast-life history trait strategies (linked to low dispersal ability and high stress intolerance). Moreover, I propose that dark diversity and functional traits can be used to enhance the nature conservation of warming sensitive organisms (e.g. lichens) by revealing which species and traits are mostly threatened to go regionally extinct or could be used in restoration. To conclude, with this thesis, I suggest that, since dark diversity is applicable to any taxonomic group, time period and global change driver, revealing how much, how fast and in what direction the whole species pool is changing, it is a promising approach to examine biodiversity in a changing world.
Dark diversity - the set of suitable but locally absent species - is an important concept to understand how ecological communities are assembled from regional to local scales. Dark diversity is the counterpart of observed diversity, which together form site-specific species pool. However, given that global change drivers affect community assembly processes across space and time, prior to this thesis no studies had explored how dark diversity could be useful to examine biodiversity dynamics in Anthropocene. Dark diversity may improve how we quantify and assess biodiversity change, and, consequently, enhance nature conservation. In this thesis, I advanced the role of dark diversity as a tool to examine biodiversity change by developing a conceptual framework in which species gains and losses are decomposed within and between species pools, revealing different biodiversity flows with possible time lags. Over millennial temporal scales, the dark diversity concept successfully depicted plant taxa facing expansion lags in their geographic range; species becoming suitable for changed environments but remaining absent. Functional traits revealed that taxa persisting in dark diversity over the Holocene and, thereby, in expansion lags, were those displaying high functional redundancy, and fast-life history trait strategies (linked to low dispersal ability and high stress intolerance). Moreover, I propose that dark diversity and functional traits can be used to enhance the nature conservation of warming sensitive organisms (e.g. lichens) by revealing which species and traits are mostly threatened to go regionally extinct or could be used in restoration. To conclude, with this thesis, I suggest that, since dark diversity is applicable to any taxonomic group, time period and global change driver, revealing how much, how fast and in what direction the whole species pool is changing, it is a promising approach to examine biodiversity in a changing world.
Description
Väitekirja elektrooniline versioon ei sisalda publikatsioone
Keywords
dark diversity, community dynamics, species composition, environmental changes, climate change, species diversity