Spatially explicit migration models of pike to support river management

De status van verschillende vissoorten in ons land, waaronder ook snoek (Esox lucius) voldoet niet aan de gestelde Europese vereisten. Behalve door een matige chemische waterkwaliteit komt dit voornamelijk door een ondermaatse habitatkwaliteit door habitatdegradatie, fragmentatie en obstructie. Rivierbeheerders plannen daarom maatregelen om het habitat te beschermen, te verbeteren of opnieuw toegankelijk te maken voor migrerende vissen. Habitatgeschiktheid- en soortverspreidingsmodellen kunnen helpen om het effect van deze maatregelen te voorspellen. Deze modellen zijn vaak niet in staat rekening te houden met factoren die gerelateerd zijn aan migratie en toegankelijkheid omdat ze niet ruimtelijk expliciet en dynamisch tegelijk zijn. In dit doctoraatsonderzoek evalueerden we de toepasbaarheid voor het simuleren van snoekmigratie van twee modelleertechnieken die wel geschikt lijken: Individueel Gebaseerde Modellen (IBMs) en Cellulaire Automaten (CAs). Daarnaast onderzochten we de migratiedynamiek, het habitatgebruik en de habitatpreferentie van volwassen snoeken ter ondersteuning van het rivierbeheer. Hiervoor werden veldgegevens verzameld van snoeken in de Ijzer (West-Vlaanderen) m.b.v. radiotelemetrie. De resultaten van dit onderzoek wijzen op een goede toepasbaarheid van IBMs en moeilijkheden bij het toepassen van de CAs voor de simulatie van snoekmigratie. De analyses van de veldgegevens tonen grote individuele verschillen in gedrag en onderlijnen het belang van habitatheterogeniteit en het toegankelijk maken van bestaande geschikte habitats voor volwassen snoeken. Dit onderzoek geeft meer inzicht in het ruimtelijk expliciet simuleren van snoekmigratie en levert kennis over de ecologie van snoek met directe suggesties voor rivierbeheerders

Making sense of changing coastal systems: overcoming barriers to climate change adaptation using fuzzy cognitive mapping

This thesis describes the role and value of Fuzzy Cognitive Mapping (FCM) in undertaking coastal climate change adaptation at the local scale, comparing FCM against existing, scenario-based adaptation methods in overcoming known barriers to adaptation. It describes the attributes and limitations of FCM as a modelling tool, exploring what must be accounted for in considering the use of FCM in mixed stakeholder settings where individual and group knowledge must be integrated to form a view of the system under study, discussing in some detail the facilitation strengths and weaknesses inherent to the method. These issues are then described via reference to case-studies in Ireland and Scotland, drawing inferences regarding the ease with which an FCM-based approach to adaptation might be substituted for orthodox, scenario-based adaptation. This is found to not only be feasible, but preferable, provided there is sufficient facilitation capacity on hand to manage the added complexity that FCM carries over simple narrative scenario development. Adding to the value that FCM offers in adaptation contexts, the thesis also explores its value as both a diagnostic tool for establishing what additional capacity building or data may be required by adaptation decision makers, and also as a tool for gauging the extent to which resilience gains (or losses) might be measured. Although FCM cannot be claimed to provide a robust objective measure of resilience gains or losses, it can nevertheless usefully illustrate to decision makers the strengths and limitations of their own understanding of the systems which they must manage. This is perhaps where the future of FCM-based systems analysis in support of adaptation may ultimately lie

Towards the "resilience thinking": the effects of forest management on ecosystem services provision

Over the last decades, human-induced effects on Earth systems increasingly undermined the availability of natural capital stocks and flows. Climate change effects, land use and cover transformations, and unsustainable management practices strongly reduced the resilience, resistance, and stability of ecosystems, through compromising biodiversity conservation and services provision. In particular, forest resources faced increasing external disturbances, stresses and impacts, thus reducing their capacity to continuously provide benefits to local communities. In order to face these substantial changes, forest management is now called to improve ecosystem resilience, mainly through implementing adaptive strategies and more sustainable practices. The aim of research is twofold: (i) to assess the effects of management strategies and practices on forest ecosystem resilience, particularly by analyzing and describing the impact of alternative management approaches on biodiversity conservation and services provision; and (ii) to provide insights on how to improve forest ecosystem resilience through implementing the “resilience thinking” in practical forest management. By providing the results from specific case studies, the research develops throughout the following steps: (i) describing how forest management approached the concepts of sustainability and resilience over the last decades, from global to local scale; (ii) reviewing the main economic and ecological foundations in assessing forest ecosystem services; (iii) giving a picture of some recent approaches for mapping and quantifying forest ecosystem services, including the use of different indicators; (iv) reporting the main effects of forest management on ecosystem services provision both at landscape and stand scale; and (v) delineating useful guidelines to implement the “resilience thinking” in forest management. Although the effects from other disturbances (i.e. climate and land use changes) are not treated here, the main research findings may give a substantial contribution to deeper understand the role of forest management in improving forest ecosystem resilience, as well as to better orient adaptive strategies from stand to landscape scale towards ensuring both forest health and vitality and benefits to local communities in the future.Negli ultimi decenni, gli effetti dell’uomo sui sistemi terrestri hanno crescentemente minacciato la disponibilità dello stock e dei flussi di capitale naturale. Gli effetti dei cambiamenti climatici, le trasformazioni nell’uso e copertura del suolo, e le pratiche di gestione non sostenibile hanno fortemente ridotto la resilienza, la resistenza e la stabilità degli ecosistemi, compromettendo così la conservazione della biodiversità e l’approvvigionamento dei servizi ecosistemici. In particolare, le risorse forestali si sono confrontate con disturbi esterni, stress e impatti, riducendo così la loro capacità di fornitura di benefici alle comunità locali. Al fine di confrontarsi con questi cambiamenti sostanziali, la gestione forestale è chiamata a migliorare la resilienza ecosistemica, prevalentemente attraverso l’adozione di strategie adattative e pratiche più sostenibili. L’obiettivo di questa ricerca è duplice: (i) valutare gli effetti delle pratiche e strategie gestionali sulla resilienza degli ecosistemi forestali, in particolare mediante l’analisi e la descrizione degli impatti di approcci alternativi di gestione sulla conservazione della biodiversità e l’approvvigionamento dei servizi; e (ii) fornire approfondimenti su come migliorare la resilienza degli ecosistemi forestali mediante l’adozione del “pensiero resiliente” nella gestione forestale pratica. Attraverso la presentazione dei risultati di casi-studio specifici, la ricerca si sviluppa sui passaggi seguenti: (i) descrivere come la gestione forestale ha approcciato i concetti di sostenibilità e resilienza negli ultimi decenni, dalla scala globale a quella locale; (ii) rivedere i principali fondamenti economici ed ecologici nella valutazione dei servizi ecosistemici forestali; (iii) fornire un’immagine di alcuni approcci recenti alla mappatura e quantificazione dei servizi ecosistemici forestali, includendo l’uso di diversi indicatori; (iv) riportare gli effetti principali della gestione forestale sull’approvvigionamento dei servizi ecosistemici sia a scala di paesaggio che di popolamento; (v) tracciare delle linee-guida utili all’adozione del “pensiero resiliente” nella gestione forestale. Sebbene gli effetti di altri disturbi (come, per esempio, i cambiamenti climatici o nell’uso del suolo) non sono trattati, i principali risultati di ricerca possono dare un contributo sostanziale a una più approfondita comprensione del ruolo della gestione forestale nel miglioramento della resilienza degli ecosistemi forestali, così come a un miglior orientamento della gestione adattativa dalla scala di popolamento a quella di paesaggio, volta ad assicurare sia la vitalità e la salute degli ecosistemi forestali, sia i benefici alle comunità locali.Dottorato di ricerca in Management and conservation issues in changing landscapes (XXVI ciclo