Fridolin Zimmermann

Bio: Fridolin Zimmermann is an academic researcher from KORA Organics. The author has contributed to research in topics: Population & Eurasian lynx. The author has an hindex of 21, co-authored 45 publications receiving 2424 citations. Previous affiliations of Fridolin Zimmermann include University of Lausanne.

Recovery of large carnivores in Europe’s modern human-dominated landscapes

Abstract: The conservation of large carnivores is a formidable challenge for biodiversity conservation. Using a data set on the past and current status of brown bears (Ursus arctos), Eurasian lynx (Lynx lynx), gray wolves (Canis lupus), and wolverines (Gulo gulo) in European countries, we show that roughly one-third of mainland Europe hosts at least one large carnivore species, with stable or increasing abundance in most cases in 21st-century records. The reasons for this overall conservation success include protective legislation, supportive public opinion, and a variety of practices making coexistence between large carnivores and people possible. The European situation reveals that large carnivores and people can share the same landscape.

"Which camera trap type and how many do I need?" A review of camera features and study designs for a range of wildlife research applications

Abstract: Automatically triggered cameras taking photographs or videos of passing animals (camera traps) have emerged over the last decade as one of the most powerful tool for wildlife research. In parallel, a wealth of camera trap systems and models has become commercially available, a phenomenon mainly driven by the increased use of camera traps by sport hunters. This has raised the need for developing criteria to choose the suitable camera trap model in relation to a range of factors, primarily the study aim, but also target species, habitat, trapping site, climate and any other aspect that affects camera performance. There is also fragmented information on the fundamentals of sampling designs that deploy camera trapping, such as number of sampling sites, spatial arrangement and sampling duration. In this review, we describe the relevant technological features of camera traps and propose a set of the key ones to be evaluated when choosing camera models. These features are camera specifications such as trigger speed, sensor sensitivity, detection zone, flash type and flash intensity, power autonomy, and related specifications. We then outline sampling design and camera features for the implementation of major camera trapping applications, specifically: (1) faunal inventories, (2) occupancy studies, (3) density estimation through Capture-Mark-Recapture and (4) density estimation through the Random Encounter Model. We also review a range of currently available models and stress the need for standardized testing of camera models that should be frequently updated and widely distributed. Finally we summarize the "ultimate camera trap", as desired by wildlife biologists, and the current technological limitations of camera traps in relation to their potential for a number of emerging applications. Download the complete issue.

Status, management and distribution of large carnivores – bear, lynx, wolf & wolverine – in Europe

Abstract: Large carnivores (bears Ursus arctos, wolves Canis lupus, lynx Lynx lynx and wolverines Gulo gulo) are among the most challenging group of species to maintain as large and continuous populations or to reintegrate back into the European landscape. Political, socioeconomic and society changes challenge past management approaches in some of the large populations. At the same time local improvements in habitat quality, the return of their prey species, public support and favourable legislation allow for the recovery of some small populations. Several of Europe’s large carnivore populations are large and robust, others are expanding, some small populations remain critically endangered and a few are declining. [ ] Large carnivores need very large areas and their conservation needs to be planned on very wide spatial scales that will often span many intra‐ and inter‐ national borders. Within these large scales conservation and management actions need to be coordinated. To facilitate coordination, a common understanding of the present day conservation status of large carnivores at national and population level is an important basis. [ ] The aim of this summary report is to provide an expert based update of the conservation status of all populations identified by the Large Carnivore Initiative for Europe (LCIE), available in the document “Guidelines for Population Level Management Plans for Large Carnivores” (Linnell et al. 2008) and/or in the various Species Online Information Systems (http://www.kora.ch/sp‐ois/ ; also see Appendix 1). [ ] However, methods used to monitor large carnivores vary and a direct comparison over time or among populations will never be possible at a continental scale. It is more realistic to have an insight into the general order of magnitude of the population, its trend and permanent range as the “currencies” for comparisons and assessments (see point 2). This summary also does not aim to replace the habitat directive reporting, but rather complement it. Discrepancies will likely occur due to different time periods covered and different agreements reached on common reporting criteria on a national level which has to deal with many more species. Furthermore, for several countries the most recent data or distribution map were not always available, yet. [ ] Changes in monitoring methods likely result in changing population estimates, even in stable populations. Improved and more costly methods may suddenly discover that previous estimates were too high, or may detect more individuals than previously assumed. Examples of both occur. Being aware of the change in methodology the expert assessment may still be “stable” for the population even if numbers listed in tables have changed. On the other hand, large scale “official” (government) estimates may be based on questionable or non‐transparent extrapolations that run contrary to data from reference areas within the country or similar regions from other countries. If the discrepancy is apparent, expert assessment needs to question official numbers. [ ] This summary does not aim at reviewing monitoring techniques. Examples of parameters and principles for monitoring large carnivores and some “good practice” examples have been previously compiled by the LCIE (http://www.lcie.org/Docs/LCIE%20IUCN/LCIE_PSS_m onitoring.pdf). Furthermore, references at the end of many country reports do provide ample examples of well documented and state of the art monitoring of large carnivores in Europe under a wide variety of different contexts.

Natal dispersal of Eurasian lynx (Lynx lynx) in Switzerland

Abstract: Dispersal influences the dynamics and persistence of populations, the distribution and abundance of species, and gives the communities and ecosystems their characteristic texture in space and time. The Eurasian lynx Lynx lynx is a medium-sized solitary carnivore that has been re-introduced in central Europe and currently occurs in rather small populations, where dispersal is believed to play a prominent role for the recolonization of unsettled areas and persistence of subpopulations. Between 1988 and 2001 the spatio-temporal behaviour of sub-adult Eurasian lynx was studied in two re-introduced populations in Switzerland, based on 31 juveniles of which 24 were radio-tagged to find out which factors influence dispersal. Age at independence ranged from 8.1 to 10.7 months and did not differ between populations or sex. Independence began from January to the beginning of May with a peak in April. After independence, sub-adults stayed a few days in the maternal home range. Age at dispersal differed between the areas of origin and was possibly affected by sex and the presence of new progeny. Dispersers of both sexes established transient home ranges; however, only one male in the saturated population established a transient home range. Although only females took over the maternal home range, there was no significant sex bias in the proportion of individuals that dispersed in both populations. Successful dispersers settled in a territory at distances that differed between populations with effects of sex, but not condition. The mean dispersal distance in the high-density population was 25.9 km compared to 63.1 km in the low-density population. Dispersal distances in the high-density population – shorter than those reported in other Eurasian lynx studies but comparable to those observed in an Iberian lynx population – are limited by habitat restrictions hindering connections with a neighbouring population.

Recovery of large carnivores in Europe’s modern human-dominated landscapes

Abstract: The conservation of large carnivores is a formidable challenge for biodiversity conservation. Using a data set on the past and current status of brown bears (Ursus arctos), Eurasian lynx (Lynx lynx), gray wolves (Canis lupus), and wolverines (Gulo gulo) in European countries, we show that roughly one-third of mainland Europe hosts at least one large carnivore species, with stable or increasing abundance in most cases in 21st-century records. The reasons for this overall conservation success include protective legislation, supportive public opinion, and a variety of practices making coexistence between large carnivores and people possible. The European situation reveals that large carnivores and people can share the same landscape.

REVIEW: Wildlife camera trapping: a review and recommendations for linking surveys to ecological processes

Abstract: Summary Reliable assessment of animal populations is a long-standing challenge in wildlife ecology. Technological advances have led to widespread adoption of camera traps (CTs) to survey wildlife distribution, abundance and behaviour. As for any wildlife survey method, camera trapping must contend with sources of sampling error such as imperfect detection. Early applications focused on density estimation of naturally marked species, but there is growing interest in broad-scale CT surveys of unmarked populations and communities. Nevertheless, inferences based on detection indices are controversial, and the suitability of alternatives such as occupancy estimation is debatable. We reviewed 266 CT studies published between 2008 and 2013. We recorded study objectives and methodologies, evaluating the consistency of CT protocols and sampling designs, the extent to which CT surveys considered sampling error, and the linkages between analytical assumptions and species ecology. Nearly two-thirds of studies surveyed more than one species, and a majority used response variables that ignored imperfect detection (e.g. presence–absence, relative abundance). Many studies used opportunistic sampling and did not explicitly report details of sampling design and camera deployment that could affect conclusions. Most studies estimating density used capture–recapture methods on marked species, with spatially explicit methods becoming more prominent. Few studies estimated density for unmarked species, focusing instead on occupancy modelling or measures of relative abundance. While occupancy studies estimated detectability, most did not explicitly define key components of the modelling framework (e.g. a site) or discuss potential violations of model assumptions (e.g. site closure). Studies using relative abundance relied on assumptions of equal detectability, and most did not explicitly define expected relationships between measured responses and underlying ecological processes (e.g. animal abundance and movement). Synthesis and applications. The rapid adoption of camera traps represents an exciting transition in wildlife survey methodology. We remain optimistic about the technology's promise, but call for more explicit consideration of underlying processes of animal abundance, movement and detection by cameras, including more thorough reporting of methodological details and assumptions. Such transparency will facilitate efforts to evaluate and improve the reliability of camera trap surveys, ultimately leading to stronger inferences and helping to meet modern needs for effective ecological inquiry and biodiversity monitoring.

Estimating landscape resistance to movement: a review

Abstract: Resistance surfaces are often used to fill gaps in our knowledge surrounding animal movement and are frequently the basis for modeling connectivity associated with conservation initiatives. However, the methods for quantifying resistance surfaces are varied and there is no general consensus on the appropriate choice of environmental data or analytical approaches. We provide a comprehensive review of the literature on this topic to highlight methods used and identify knowledge gaps. Our review includes 96 papers that parameterized resistance surfaces (sometimes using multiple approaches) for a variety of taxa. Data types used included expert opinion (n = 76), detection (n = 23), relocation (n = 8), pathway (n = 2), and genetic (n = 28). We organized the papers into three main analytical approaches; one-stage expert opinion, one-stage empirical, and two-stage empirical, each of which was represented by 43, 22, and 36 papers, respectively. We further organized the empir- ical approaches into five main resource selection functions; point (n = 16), matrix (n = 38), home range (n = 3), step (n = 1), and pathway (n = 1). We found a general lack of justification for choice of environmental variables and their thematic and spatial representation, a heavy reliance on expert opinion and detection data, and a tendency to confound movement behavior and resource use. Future research needs include comparative analyses on the choice of envi- ronmental variables and their spatial and thematic scales, and on the various biological data types used to estimate resistance. Comparative analyses amongst analytical processes is also needed, as well as trans- parency in reporting on uncertainty in parameter estimates and sensitivity of final resistance surfaces, especially if the resistance surfaces are to be used for conservation and planning purposes.

Use and misuse of the reduced major axis for line-fitting

Abstract: Many investigators use the reduced major axis (RMA) instead of ordinary least squares (OLS) to define a line of best fit for a bivariate relationship when the variable represented on the X-axis is measured with error. OLS frequently is described as requiring the assumption that X is measured without error while RMA incorporates an assumption that there is error in X. Although an RMA fit actually involves a very specific pattern of error variance, investigators have prioritized the presence versus the absence of error rather than the pattern of error in selecting between the two methods. Another difference between RMA and OLS is that RMA is symmetric, meaning that a single line defines the bivariate relationship, regardless of which variable is X and which is Y, while OLS is asymmetric, so that the slope and resulting interpretation of the data are changed when the variables assigned to X and Y are reversed. The concept of error is reviewed and expanded from previous discussions, and it is argued that the symmetry-asymmetry issue should be the criterion by which investigators choose between RMA and OLS. This is a biological question about the relationship between variables. It is determined by the investigator, not dictated by the pattern of error in the data. If X is measured with error but OLS should be used because the biological question is asymmetric, there are several methods available for adjusting the OLS slope to reflect the bias due to error. RMA is being used in many analyses for which OLS would be more appropriate.