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Accueil du site → Doctorat → Allemagne → 2021 → Effects of climate change and environmental disturbance on moth communities (Insecta : Lepidoptera) and their distribution patterns along a latitudinal gradient in Mongolia

Universität Bayreuth (2021)

Effects of climate change and environmental disturbance on moth communities (Insecta : Lepidoptera) and their distribution patterns along a latitudinal gradient in Mongolia

Khishigdelger Enkhtur

Titre : Effects of climate change and environmental disturbance on moth communities (Insecta : Lepidoptera) and their distribution patterns along a latitudinal gradient in Mongolia

Auteur : Khishigdelger Enkhtur,

Université de soutenance : Universität Bayreuth

Grade : Doktorin der Naturwissenschaften (Dr. rer. nat.) 2021

Résumé partiel
Globally, 8.7 million species are estimated to exist on Earth, and one million species are facing extinction due to human intervention. Biodiversity improves the environment’s resilience to disturbances, plays a vital role in sustaining ecosystem functions, and provides ecosystem services to humanity. The significant drivers of biodiversity loss are habitat loss, human population and consumption growth, and climate change. Climate warming will cause cold-adapted species to migrate to higher elevations or latitudes, searching for suitable habitats. Another factor that affects species richness and community composition is an ecological disturbance. However, it is still unclear how species will respond and how many species will disappear in the near future. Species richness (alpha diversity) is used to measure biodiversity since it is practical and widely applicable ; however, even for similar environments, the number of species differs ; therefore, it is crucial to determine the underlying causes. Beta diversity considers the changes in species composition among areas and can be partitioned into two parts, according to the origin of differences : turnover and nestedness. Turnover reflects the process of environmental filtering, while nestedness reflects colonization, such as the effects of a lack of available resources. For observing potential environmental and climate change, indicator species are used to monitor the environmental condition and assess the ecological integrity. However, how species respond to environmental change depends on their functional traits. Environmental disturbances such as overgrazing eliminate specialist species, while generalists benefit, resulting in a more homogeneous, less resilient environment. It is predicted that there will be massive biodiversity losses if current human population growth continues and if people do not change the way they interact with nature. However, globally, the availability of biodiversity data is not equal : differences may occur spatially (most databases are covering Europe and North America), taxonomically (focus on large animals such as mammals and birds and charismatic organisms such as butterflies), historically (long-term data is missing), and analytically (general pattern is missing). Therefore, we do not know exactly which species are disappearing in many places of the world and where conservation management should focus. So, it is necessary to learn how many species exist, how disturbance affects their distribution, how they respond to disturbance depending on their ecological niches, etc. in order to conserve biodiversity. In this thesis, I integrated and analyzed published data on geometrid moths and interpreted their diversity pattern ; moreover, I studied the diversity and distribution of macro moths in the field and further investigated the effects of livestock grazing on moth assemblages under different climatic conditions. The central part of the thesis was conducted at ten sites located along the latitudinal gradient in Mongolia, totaling a transect length of 860 km from the Gobi Desert into the steppe. I found a breakpoint at 46° N for both the beta diversity pattern of moth communities and precipitation and temperature. In the desert, beta diversity was due to species loss/gain, and in grassland, it was caused by species replacement

Mots clés  : Moth ; Lepidoptera ; Mongolia ; livestock ; functional traits ; beta diversity ; alpha diversity ; latitudinal gradient ; habitat disturbance ; ecoregions ; geometridae ; species checklist ; breakpoint ; piecewise regression ; grazing

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Page publiée le 31 octobre 2022