Extreme ecosystem engineering: The impact of marmots on
vegetation cover and plant nitrogen and phosphorus content in a cold,
extremely arid mountain environment.
Piotr Chibowski1*, Marcin Zegarek2,
Aleksandra Zarzycka1, Małgorzata
Suska-Malawska1,3
1Faculty of Biology, Biological and Chemical Research
Centre, University of Warsaw, Warsaw, Poland *p.chibowski2@uw.edu.pl
2Mammal Research Institute, Polish Academy of
Sciences, Białowieża, Poland
3International Platform for Dryland Research and
Education, Tottori University, Tottori, JapanAbstract
We measured the content of nitrogen and phosphorus, as well as nitrogen
stable isotopes in plant biomass and marmot faeces in a distance
gradient up to 20 meters from marmot burrows in an extremely arid
glacier valley in Eastern Pamir, Tajikistan. The goal of this study was
to test well-known mechanisms of ecosystem engineering by burrowing
animals in previously unstudied conditions. We captured aerial images of
the area inhabited by marmots to study the spatial distribution of
vegetation. There was no relationship between the presence of burrows
and vegetation cover. Burrow mounds were not colonised by plants, as
opposed to other ecosystems, where mounds are often microhabitats that
enhance plant diversity. A significant increase in N and P in
aboveground green plant biomass in the proximity of burrows was found in
one out of six studied species. Stable N isotopes did not give further
insight into N routing, contrary to our expectations. We assume that
plant growth is strongly limited by water availability, which prevents
them from utilizing the local increase in nutrients, certainly provided
by marmot activity. The results are contrary to numerous studies which
showed that the role of burrowing animals as ecosystem engineers
increases with increasing abiotic stress, including aridity. This shows
a lack of this type of study in the end of the gradient of abiotic
factors.
Keywords : long-tailed marmot, burrow, extreme, arid region,
Eastern Pamir, ecosystem engineering