Geomatics and Landscape Ecology Research Laboratory Wednesday, 20 September 2017 5:03 am  
Jochen Jaeger
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Jochen Jaeger


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Postdoctoral Project:

 

"Predicting the effects of different road network patterns on landscape connectivity and population density"

(2001-2003)

My project aims at comparing and assessing different road network patterns with respect to their impacts on species survival and population densities. The first part of the project describes road patterns, including traffic amount and spatial distribution of the roads, using network indices. A simulation model including a dispersal module and a population dynamics module is applied to estimate the effects of the road networks on landscape connectivity, population density, and species persistence. The results are used to describe landscape connectivity as a function of network indices and species characteristics such as dispersal distance, dispersal rate, reproduction rate, and mortality. This allows to design ecologically scaled landscape indices (ESLI, as discussed by Vos et al. 2001) for ranking different road network patterns according to the severity of their impacts.

In the second part of the project, the results from the model simulations are linked with empirical data. Data on the presence/absence and density of species from different landscapes are correlated to road pattern data in the same landscapes, as a test of the model results.

Research questions:

What is the relationship between landscape connectivity, species persistence, and population density (as the dependent variables) and network indices and species characteristics (as the independent variables)?

Is it feasible and advantageous to design ecologically scaled landscape indices (ESLI) in order to get simpler functions for landscape connectivity, species persistence, and population density? Which indices (network indices or ESLI) are better understood (and more likely to be used) by traffic planners?

Is it reasonable to use indices (network indices or ESLI) for predicting the effects of road patterns at all? Or does one better rely on simulation models to predict these effects?

Can we derive some general rules for an ecologically sustainable design of road patterns?

Key words:
animal dispersal, ecologically scaled landscape indices, effective mesh size, landscape connectivity, landscape dissection, landscape fragmentation, landscape metrics, network metrics, simulation model

This project was supported through a postdoctoral scholarship from the German Academy of Natural Scientists Leopoldina to Jochen Jaeger.

Since 2003, Jochen Jaeger is continuing his work as a post-doctoral research fellow at the ETH Zurich, Switzerland, in the group of Prof. Klaus C. Ewald, supported through a grant from the German Research Foundation.



References related to the project:

BOWMAN, J., JAEGER, J.A.G., FAHRIG, L. (2002): Dispersal distance of mammals is proportional to home range size. - Ecology 83(7): 2049-2055.

JAEGER, J.A.G. (2000): Landscape division, splitting index, and effective mesh size: New measures of landscape fragmentation. - Landscape ecology 15 (2): 115-130.

JAEGER, J. (2001): Curtailing landscape fragmentation by applying limiting standards or reference standards (in German, including an English summary) / Beschränkung der Landschaftszerschneidung durch die Einführung von Grenz- oder Richtwerten. - Natur und Landschaft 76 (1): 26-34.

JAEGER, J.A.G., FAHRIG, L. (2004): Effects of road fencing on population persistence. - Conservation Biology 18(6): 1651-1657.

JAEGER, J.A.G., BOWMAN, J., BRENNAN, J., FAHRIG, L., BERT, D., BOUCHARD, J., CHARBONNEAU, N., FRANK, K., GRUBER, B., TLUK VON TOSCHANOWITZ, K. (2005): Predicting when animal populations are at risk from roads: an interactive model of road avoidance behavior. - Ecological Modelling, in press.

VOS, C.C., VERBOOM, J., OPDAM, P.F.M., TER BRAAK, C.J.F. (2001): Toward ecologically scaled landscape indices. - The American Naturalist 157 (1): 24-41.


 
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