From genes to communities:

Assessing plant diversity and connectivity in kettle holes as meta-ecosystems in agricultural landscapes

PhD at Potsdam University

Supervisors: Prof. Jasmin Joshi and Prof. Ralph Tiedemann

My PhD was part of the BioMove Graduate School. The main goal of BioMove is to integrate Biodiversity with Movement. More information about BioMove here

In my PhD project I focused on plants and how they disperse (seed and pollen) among kettle holes and their diversity patterns as a result of this movement.

The complete thesis can be find here

Seed dispersal of two wetland species between kettle holes: a model approach

As an extra aside project after finishing my PhD, in collaboration with Dr. Jinlei Zhu we are studying the dispersal seed distances of Typha latifolia and Phragmites australis between kettle holes under different scenarios of land-use management. Dr. Zhu has developed a very sophisticated model with different parameters including properties of the plant (release seed height, terminal velocity of the seeds) and also the surrounding vegetation. More about his work can be found here

Typha latifolia close to Buchenhain, Uckermark (Germany)
Bee diversity in kettle holes
Bumblebee (Bombus sp.) feeding from Salix sp.

This was the third part of my PhD project. In this project I focused on the bee diversity found in the kettle holes. The idea behind was that these ponds might be important natural habitats for resources (nectar, pollen), where bees can forage and contribute to the pollination in a landscape level.

Genetic connectivity in wetland species between kettle holes in agricultural landscapes
Lycopus europaeus, Uckermark (Germany)

This was the second part of my PhD project part of BioMove graduate school at University of Potsdam.

In this project, we evaluated the degree of connectivity of four wetland species: Lycopus europaeus, Oenanthe aquatica, Typha latifolia and Phragmites australis. They have different movement and reproduction strategies, the first two are mainly pollinated by bees and seeds are dispersed by water, while the last two pollen and seeds are transported by wind. They also differ in the degree of clonality, Typha and Phragmites reproduce almost only clonally, Lycopus less common and Oenanthe almost never.

In this study we compared these strategies in terms of genetic diversity and gene flow inferred from molecular markers and relate these results with landscape characteristics such as kettle hole area, kettle hole density and diversity of plants and bees occurring within the kettle holes.

Plant diversity and dispersal traits in two different types of kettle holes: permanent and ephemeral
Permanent kettle hole in Buchenhain, Uckermark (Germany)

This was the first part of my PhD. In this study we compared plant diversity occurring in two types of kettle holes: permanent and ephemeral, and also their dispersal traits. We found that big kettle holes harbor more number of species but the plant composition differed between types of kettle holes. Interestingly, the degree of isolation (number of other surrounding kettle holes) was only important in the ephemeral ones. These results suggest that ephemeral ponds are more dynamic and depend on other surrounding ponds to get plant species. Also in these ephemeral ponds, dispersal traits of the plant communities were more adapted to be dispersed by humans (probably by farmers or agricultural tractors).

Studies like this show that all different types of ponds are important to get connectivity and movement of species in a landscape level. We recommend to pay attention to the ephemeral types in particular. Ephemeral ponds are threatened since they can dry out some years and farmers would just plough through. They harbor a unique diversity of plants and therefore must be conserved.

Ephemeral (temporal) kettle hole in the middle in Damerow, Uckermark (Germany) Foto credit: Carlos Acame.
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