Skip to content

About Dr Achaz von Hardenberg

I joined the Department of Biological Sciences at the University of Chester in August 2015 after having worked for 10 years as a research biologist for the Gran Paradiso National Park (GPNP, Northwestern Italian Alps) where I was in charge of long term ecological research and conservation projects. In 2009-10 I took a year off my job at GPNP to work as a postdoc visiting researcher at the National Centre for Statistical Ecology (University of Kent, UK). Previously, I obtained my PhD from the University of Sherbrooke (Canada) in 2005 and a Degree in Biological Sciences (BSc + MSc) in 1998 from the University of Pavia (Italy). 


I currently co-teach on the following BSc modules at the University of Chester:

  • BI4114 Data Handling and Project Design
  • BI4141 Global Biodiversity: Concepts and Threats
  • BI5110 Research Methods
  • BI5118 Behavioural Ecology
  • BI5121 Field Ecology
  • BI6129 Animal Behaviour and Conservation

I also co-teach in the MSc programme in Wildlife Conservation on the following modules:

  • BI7137 Managing Wildlife Populations and Landscapes
  •  BI7139 Field Research Techniques for Wildlife Conservation

I also regularly teach short courses and workshops on the use of the statistical environment and language R, Bayesian methods for ecology, Causal inference and Phylogenetic Path Analysis.


Causal inference in ecology and evolutionary biology

Disentangling cause-effect relationships is a primary, although often understated, goal in ecological and evolutionary studies. However inferring causality is a daunting task in the absence of controlled and randomized experiments, which, more often than not, are unfeasible in ecology and evolutionary biology. With few exceptions field ecologists and evolutionary biologists thus renounce to make any inference about causality from their observatory studies, resigning to the sobering precept - we all learnt during our undergraduate statistics courses - that correlation does not imply causation. In the last 20 years new powerful and elegant methods for causal inference from observational data, based on graph theory (e.g. Structural Equation models and Path analysis) have been developed and only recently introduced in ecology and in evolutionary biology. The further development of these methods is currently a very active field of research but the application of these methods in ecology, evolution and conservation is yet only at the surface of its potential.  I have applied these methods extensively during my career, using them to disentangle the complex relationships between corticosteroid hormones, behaviour and life history traits (Decristophoris et al. 2007, Costantini et al. 2012, Corlatti et al. 2012) and recently contributed to introducing them to molecular ecology (Brambilla et al. 2015). In collaboration with Dr. Alejandro Gonzalez-Voyer (UNAM, Mexico), I have recently extended causal inference to phylogenetic comparative studies developing a method for Phylogenetic Path Analysis (von Hardenberg and Gonzalez-Voyer, 2013, Gonzalez-Voyer and von Hardenberg 2014), an approach that we are now developing further in a Bayesian Structural Equation Modeling framework. This work has been supported by a University of Chester International Research Excellence Award, funded under the Santander Universities scheme.

Current collaborations:

Dr. Alejandro Gonzalez-Voyer 

Population dynamics, life history and conservation of mountain ungulates

I have had a scientific “love affair” with mountain ungulates since my time as an undergraduate student.  Back in 1995 I had the chance to participate as a field assistant in a research expedition, led by Prof. Sandro Lovari (University of Siena, Italy) in the Kumbu Valley (Nepal) for a study on the behaviour of Himalayan tahr (Hemitragus jemlahicus). I then worked for my Master’s thesis on the territorial behaviour of Alpine chamois (Rupicapra rupicapra) leading to one of my very first peer-reviewed publications (von Hardenberg et al. 2000a). After spending a summer working in the field on incisor breath in bighorn sheep Ovis canadensis  (von Hardenberg, Shipley and Festa-Bianchet, 2003) within the long term research project in Ram Mountain (Alberta, Canada) lead by Prof. Marco Festa-Bianchet (University of Sherbrooke), I finally started my PhD, under Marco’s supervision, on the population dynamics and life history of Alpine ibex (Capra ibex), participating thus from the very beginning in the long term research project on individually tagged Alpine ibex in the Levionaz Study area of the Gran Paradiso National Park, Together with Dr. Bruno Bassano (GPNP) I maintained this long term project in the subsequent years in my role as GPNP biologist and continue to be involved in it in the present day. Every summer researchers and students in Levionaz continue the tedious work of collecting data on the behaviour of tagged individuals, collecting feces for fecal counts of gastrointestinal parasite eggs and weighting them on remote scales in salt licks (Bassano et al. 2003). Our long term dataset on Alpine ibex, including horn measurements (an important secondary sexual trait in males) and total population counts (available for GPNP since 1956) allowed us to gain a better understanding of the links between individual genetic variability and life history traits (von Hardenberg et al. 2007, Brambilla et al. 2015), horn growth and senescence (von Hardenberg et al. 2004) and of the drivers of the dynamics of this population (von Hardenberg et al. 2000b, Jacobson et al. 2004, Pettorelli et al. 2007, Mignatti et al. 2012). Currently, together with Dr. Bruno Bassano and Alice Brambilla, a former PhD student on this project and current main collaborator, we are working on the effects of climate change on horn growth as well as on paternity estimation and the link between MHC genes and parasite resistance (in collaboration with the research group of Prof. Lukas Keller at the University of Zürich). In collaboration with Dr. Rachel McCrea (University of Kent, UK) I am instead working on an Integrated Population Model, integrating long term individual based data with population counts to disentangle the intrinsic and environmental drivers of changes in vital rates. 

Current collaborations:

Behavioural ecology of Alpine marmots (Marmota marmota)

Alpine marmots (Marmota marmota) are ground dwelling rodents living on the European Alps, with a complex social structure:  Family groups can include up to 20 members, including a dominant couple of adults, newborns of the year and subdominants born in the previous years, staying in the family group up to the age of 3-4 years before dispersing or inheriting their parents’ territory. Alpine marmots are key elements in the alpine ecosystem, both as grazers as well as important preys of Golden Eagles (Aquila chrysaetos) and Red foxes (Vulpes vulpes): a fact which, together with their complex sociality, makes them an extremely interesting subject for long term studies investigating the effects of environmental change in social species.  In 2006, in collaboration with Dr. Bruno Bassano (GPNP, Italy), Prof. Giuseppe Bogliani (University of Pavia, Italy) and Prof. Denis Reale (UQAM, Canada), I started a long-term research project on the behavioural ecology of Alpine marmots. This ongoing study is based on individually tagged Alpine marmots (more than 250 tagged individuals since 2006) observed over their lifetime in 20 family groups in the Orvieilles study area (2100-2300 m a.s.l., Gran Paradiso National Park, Italy).  Up to now our research work in Orvieilles has focused on vigilance behaviour (Ferrari et al. 2009), the factors affecting Flight Initiation Distance (Dumont et al. 2012), territorial behaviour (Pasquaretta et al. 2012, 2015), the presence of copying styles (Ferrari et al. 2012) and their relationship with cortisol and oxidative stress (Costantini et al 2012).  Currently we are using our long term database to analyze variability in social networks, ecological and social drivers of survival and dispersal and the interaction between personality and life history traits.

Current collaborations:

Current Postgraduate Research Students:

  • Caterina Ferrari (PhD candidate at the University of Zürich, Switzerland. Co-supervised with Prof. Denis Reale) 

Prospective MRes and PhD students interested in working in any of the above research lines, please contact me!

Published Work

Scridel D., Bogliani B., Pedrini P., Iemma A., von Hardenberg A.  and Brambilla M. (2017) Thermal niche predicts recent range variation in birds. Climate Research. 73(3), 207-216.   

Zanet S., Miglio G., Ferrari C., Bassano B., Ferroglio E. and  von Hardenberg, A. (2017) Higher Risk of Gastrointestinal Parasite Infection at Lower Altitudes Suggests Possible Constraints in the Distributional Niche of Alpine Marmots.  PLOS ONE. 12(8),e0182477.  

Tiberti, R., Ottino, M., Brighenti, S., Iacobuzio, R., Rolla, M., von Hardenberg, A.  and Bassano B. (2017) Involvement of recreational anglers in the eradication of alien brook trout from high altitude lakes. Journal of Mountain Ecology, 10, 13-26  

Ranghetti, L., Bassano B., Bogliani G., Palmonari A., Formigoni A, Stendardi L. and  von Hardenberg A. (2016) MODIS time series contribution for the estimation of nutritional properties of alpine grassland. European Journal of Remote Sensing. 49, 691-718.

Quevedo P. von Hardenberg A.,  Pastore H., Álvarez J. and  Corti P. (2016) Predicting the potential distribution of the endangered huemul deer Hippocamelus bisulcus in North Patagonia.  Oryx, DOI:

Pasquaretta C., Busia L., Ferrari C., Bogliani, G., Reale, D., von Hardenberg, A. (2015) Helpers influence on territory use and maintenance in Alpine marmot groups. In press. Behaviour. Accepted on 26.03.2015

Brambilla B., Biebach I., Bassano B., Bogliani G. and von Hardenberg A. (2015) Direct and indirect causal effects of heterozygosity on fitness-related traits in Alpine ibex.  Proc. Roy. Soc. B. doi: 10.1098/rspb.2014.1873

Gonzalez-Voyer A.* and von Hardenberg A.*  (2014) An introduction to Phylogenetic Path Analysis. In: Modern phylogenetic comparative methods and their application in evolutionary biology. (Garamszegi L.S., Ed.). Springer Verlag, Berlin. pp. 201-230 (*Equal contribution)

Tiberti R., von Hardenberg A. and Bogliani G. (2014)  Ecological impact of introduced fish in high altitude lakes: a case of study from the European Alps. Hydrobiologia, 724(1):1:19 doi:10.1007/s10750-013-1696-1

von Hardenberg A.* and Gonzalez-Voyer A.* (2013) Disentangling evolutionary cause-effect relationships with phylogenetic confirmatory path analysis. Evolution 67: 378–387, doi: 10.1111/j.1558-5646.2012.01790.x   (*Equal contribution)

Brambilla A., von Hardenberg A., Kristo O., Bassano B. and Bogliani G. (2013) Don’t spit in the soup: faecal avoidance in foraging wild Alpine ibex, Capra ibex.  Animal Behaviour, 86(1):153-158, doi: 10.1016/j.anbehav.2013.05.006

Viterbi R., Cerrato C., Bassano B., Bionda R., von Hardenberg A., Provenzale A.  and Bogliani G. (2013) Patterns of biodiversity in the northwestern Italian Alps: a multi-taxa approach. Community Ecology 14(1):18-30. doi: 10.1556/ComEc.14.2013.1.3

Ferrari, C., Pasquaretta, C., Carere, C., Cavallone, E., von Hardenberg, A. and Réale, D. (2013). Testing for the presence of coping styles in a wild mammal. Animal Behaviour, 85(6):1385-1396, doi: 10.1016/j.anbehav.2013.03.030

Corlatti L. Béthaz S., von Hardenberg A., Bassano B., Palme, R. & Lovari S. (2012) Hormones, parasites and male mating tactics in Alpine chamois: identifying the mechanisms of life history trade-offs. Animal Behaviour, 84(4):1061-170,   doi: 10.1016/j.anbehav.2012.08.005

Mignatti A., Casagrandi R., Provenzale A. von Hardenberg A. and Gatto M. (2012) Sex and age-structured models for Alpine ibex Capra ibex ibex population dynamics. Wildlife Biology, 18 (3):318-332

Ferrari C., Pasquaretta C., von Hardenberg A. and Bassano B. (2012) Intraspecific killing and  cannibalism in  adult Alpine marmots Marmota marmota. Ethology, Ecology and Evolution, 24 (4): 388-394

Dumont F. Pasquaretta C., Bogliani G. Reale D. & von Hardenberg A. (2012) Flight initiation distance and starting distance: biological effect or mathematical artifact? Ethology, 118(11):1051-1062.

Tiberti, R and von Hardenberg A. (2012) Impact of introduced fish on Common frog (Rana temporaria) close to its altitudinal limit in alpine lakes. Amphibia-Reptilia, 33(2):303-307.

Pasquaretta C., Bogliani G. Ferrari C., Ranghetti L. and von Hardenberg A. (2012) The Animal Locator: A new method for the accurate and fast collection of animal locations for visible species. Wildlife Biology, 18(2):202-214.

Costantini D., Ferrari C., Pasquaretta C., Carere C., von Hardenberg A. and Reale D.  (2012) Interplay between plasma oxidative state, cortisol and coping styles in wild Alpine marmots (Marmota marmota). Journal of Experimental Biology, 215(2):374-383.  

Rughetti, M. , Toïgo, C.,  von Hardenberg A., Rocchia E. and M. Festa-Bianchet (2011). Effects of an exceptionally snowy winter on chamois survival. Acta Theriologica, 56(4): 329-333.

Ferrari C. Bogliani G. and von Hardenberg A. (2009) Alpine marmots (Marmota marmota) adjust vigilance behaviour according to environmental characteristics of their surrounding. Ethology, Ecology & Evolution, 21:355-364.

Bergeron P., Festa-Bianchet M., von Hardenberg A. and Bassano B. (2008). Heterogeneity in male horn growth and longevity in a highly sexually dimorphic ungulate. Oikos, 117, 77-82.

Decristophoris P.M.A., von Hardenberg A. and McElligott A.G. (2007). Testosterone is positively related to the output of nematode eggs in male Alpine ibex (Capra ibex) faeces. Evolutionary Ecology Research, 9:1277-1292.

von Hardenberg A., Bassano B., Festa-Bianchet M., Luikart G., Lanfranchi P. and Coltman D. (2007). Age dependent genetic effects on a secondary sexual trait in male Alpine ibex (Capra ibex). Molecular Ecology, 16:1969-1980.

Pettorelli N., Pelletier F., von Hardenberg A., Festa-Bianchet M. and Coté S. (2007). Early onset of vegetation growth versus rapid green-up: impacts on juvenile mountain ungulates. Ecology, 88(2):381-390.

Jacobson A.R., Festa-Bianchet M., Provenzale A., von Hardenberg A. and Bassano B. (2006) Comment on Lima & Berryman (2006): the Alpine ibex revisited. Climate Research, 32:137.

von Hardenberg A., Bassano B., Zumel Arranz M.d.P. and G. Bogliani. (2004). Horn growth but not asymmetry heralds the onset of senescence in male Alpine ibex. Journal of Zoology, 263: 425-432.

Jacobson, A.R., Provenzale, A., von Hardenberg A., Bassano B. and M. Festa-Bianchet. (2004). Climate forcing and density dependence in a mountain ungulate population. Ecology, 85(6): 1598-1610.

Maudet C., Luikart G., Dubray D., von Hardenberg A., Taberlet P. (2004). Low genotyping error rates when analysing microsatellite DNA from wild ungulate faeces sampled in winter. Molecular Ecology Notes, 4(4): 772-775.

Bassano B., von Hardenberg A., Pelletier. F. and G. Gobbi. (2003). A method to weight free-ranging ungulates without handling. Wildlife Society Bulletin. 31(4):1205–1209.

von Hardenberg A., Shipley B. and M. Festa Bianchet (2003). Another one bites the dust: Does incisor arcade size affect mass gain and survival in grazing ungulates? Canadian Journal of Zoology, 81 (9): 1623-1629.

Bassano B., Perrone A. and von Hardenberg A. (2003) Body weight and horn development in Alpine chamois, Rupicapra rupicapra (Bovidae, Caprinae). Mammalia, 67(1):65-73.

von Hardenberg A., Bassano B., Peracino, A. & S. Lovari (2000a). Male alpine chamois occupy territories at hotspots before the mating season. Ethology, 106:617-630.

von Hardenberg A., Bassano B., Peracino V., von Hardenberg J. & Provenzale A. (2000b) Preliminary results on the temporal variability of the Alpine ibex population in the Gran Paradiso National Park. Journal of Mountain Ecology, 5:201-210.

Bertolino S., von Hardenberg A. & G. Ribetto (2000) Population dynamics of mouflon, Ovis [orientalis] musimon, in a protected area in the Italian Alps. Journal of Mountain Ecology, 5:193-200.