Katja Schiffers

University of Bonn - INRES

CONTEXT: Late spring frosts are a major problem for apple production in Germany. Frost events frequently lead to yield losses and quality reduction. This has motivated the development of several frost protection measures, which differ in terms of effectiveness, costs and workload. In many cases, it is an open question for fruit growers if investing...

Temperate fruit trees require exposure to chill and heat conditions to overcome the dormant period in winter and resume growth in spring. Rising temperatures due to climate change have already impacted winter chill accumulation in horticulturally vital growing regions worldwide. Afghanistan’s intra-regional differences make the country favorable fo...

Ground beetles (carabids) constitute an important functional component of biodiversity in agroecosystems, mainly because of their role as predators of pests, but also as consumers of weed seeds and as prey to other organisms. Over the past few decades, there has been a marked and continuous decline of ground beetles in Europe, and many species of t...

Phenology models are crucial tools for assessing climate change impacts in forestry, ecology and agriculture. Such models are typically calibrated with observational or experimental data and validated with a set of independent observations. While there have been extensive discussions about validation approaches, systematic studies assessing the eff...

In the face of a changing climate, yield stability is becoming increasingly important for farmers and breeders. Long-term field experiments (LTEs) generate data sets that allow the quantification of stability for different agronomic treatments. However, there are no commonly accepted guidelines for assessing yield stability in LTEs. The large diver...

Forecasting spring phenology of temperate fruit trees is of high concern for orchard plannersand fruit producers, particularly in the context of climate change. Responding to this need, horticultural researchers have developed models to estimate chill and heat requirements and project dormancy release. Despite some successes in dormancy modeling, s...

In the face of a changing climate, yield stability is becoming increasingly important for farmers and breeders. Long-term field experiments (LTEs) generate data sets that allow the quantification of stability for different agronomic treatments. However, there are no commonly accepted guidelines for assessing yield stability in LTEs. The large diver...

In this article, we identify possibilities and limits of processing as yet unused data sources for spatio-temporal biodiversity trend analyses in Germany. The sMon synthesis project (https://www.idiv.de/smon) of the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig is a joint working group of federal and state authoritie...

Aim Seasonal bird migration is one of the most fascinating global ecological phenomena. Yet, the biogeographic scenarios and climatic drivers that led single species or entire lineages to evolve seasonal migration between disjunct breeding and wintering ranges remain unclear. Based on distribution and phylogenetic data for all birds worldwide, we e...

In the context of biological research, data is being produced in larger quantities each year. The need for such data also increases, as research approaches are increasingly data-driven and relying on ‘big data’. However, data are often scattered, hard to integrate, and their long-term preservation is not secured. To overcome this mismatch, the Germ...

Although it is generally recognized that global biodiversity is declining, few studies have examined long-term changes in multiple biodiversity dimensions simultaneously. In this study we quantified and compared temporal changes in the abundance, taxonomic diversity, functional diversity and phylogenetic diversity of bird assemblages, using roadsid...

Increasing biodiversity loss due to climate change is one of the most vital challenges of the 21(st) century. To anticipate and mitigate biodiversity loss, models are needed that reliably project species' range dynamics and extinction risks. Recently, several new approaches to model range dynamics have been developed to supplement correlative speci...

Investigating how interactions among plants depend on environmental conditions is key to understand and predict plant communities’ response to climate change. However, while many studies have shown how direct interactions change along climatic gradients, indirect interactions have received far less attention. In this study, we aim at contributing t...

Spatial and temporal management measures to reduce nontarget catch are important strategies for rebuilding overfished rockfish (Sebastes spp.) populations in the Northeast Pacific. We describe efforts to support reducing rockfish bycatch in central California trawl fisheries by testing the efficacy of move-on rules on catch data from 2002 to 2010....

Ongoing and predicted global change makes understanding and predicting species’ range shifts an urgent scientific priority. Here, we provide a synthetic perspective on the so far poorly understood effects of interspecific interactions on range expansion rates. We present theoretical foundations for how interspecific interactions may modulate range...

Hutchinson defined species' realized niche as the set of environmental conditions in which populations can persist in the presence of competitors. In terms of demography, the realized niche corresponds to the environments where the intrinsic growth rate ( r ) of populations is positive. Observed species occurrences should reflect the realized niche...

ALADYN is a freely available cross-platform C++ modeling framework for stochastic simulation of joint allelic and demographic dynamics of spatially-structured populations. Juvenile survival is linked to the degree of match between an individual's phenotype and the local phenotypic optimum. There is considerable flexibility provided for the demograp...

Evolutionary adaptation is a key driver of species' range dynamics. Understanding the factors that affect rates of adaptation at range margins is thus crucial for interpreting and predicting changes in species' ranges. The spatial structure of environmental conditions is one of the determinants of whether and how quickly adaptations occur. However,...

The evolutionary potential of populations is mainly determined by population size and available genetic variance. However, the adaptability of spatially structured populations may also be affected by dispersal: positively by spreading beneficial mutations across sub-populations, but negatively by moving locally adapted alleles between demes. We dev...

The demand for projections of the future distribution of biodiversity has triggered an upsurge in modelling at the crossroads between ecology and evolution. Despite the enthusiasm around these so-called biodiversity models, most approaches are still criticised for not integrating key processes known to shape species ranges and community structure....

Abstract Disturbances' role in shaping communities is well documented but highly disputed. We suggest replacing the overused two-trait trade-off approach with a functional group scheme, constructed from combinations of four key traits that represent four classes of species' responses to disturbances. Using model results and field observations from...

Dispersal is a key determinant of a population's evolutionary potential. It facilitates the propagation of beneficial alleles throughout the distributional range of spatially outspread populations and increases the speed of adaptation. However, when habitat is heterogeneous and individuals are locally adapted, dispersal may, at the same time, reduc...

Aim To evaluate the evolutionary dynamics of the ecological niche by quantifying the modes and rates of ecological niche evolution (with a particular focus on climatic parameters) and species diversification. Location Greater Cape Floristic Region, southern Africa. Methods Using the genus Babiana (Iridaceae) from the Cape flora, South Africa, we st...

1. Phylogenetic signal is the tendency of related species to resemble each other more than species drawn at random from the same tree. This pattern is of considerable interest in a range of ecological and evolutionary research areas, and various indices have been proposed for quantifying it. Unfortunately, these indices often lead to contrasting re...

Aim Biotic interactions – within guilds or across trophic levels – have widely been ignored in species distribution models (SDMs). This synthesis outlines the development of ‘species interaction distribution models’ (SIDMs), which aim to incorporate multispecies interactions at large spatial extents using interaction matrices. Location Local to glo...

Diagram of the custom built UV illuminated imaging box showing the UV lighting (upper centre), camera (right) and aquarium (left) containing sediment (brown) and luminophores (pink). The inside of the box is painted matt black to minimise internal reflection. A side of the box is removed in the diagram to show the inside. Drawn to scale (Box size =...

The sum of squares (colour shades) between the activity parameter and the mean distance of particle displacement for the sample dataset for Hediste diversicolor. Tracer difference (tracerdif) = 0.9. The sums of squares are minimised as distance→6.5 and activity→0.5 (darkest green shading). (TIF)

Raw counts of the vertical distribution of pink luminophore tracer particles over time for the polychaete, Hediste diversicolor , used in the worked example detailed in Supplemental Information S1. (TXT)

Programming code in Tinn-R text editor format ( http://sciviews.org/Tinn-R/ ) for the process-based, spatially explicit (2D) bioturbation simulation model. (R)

Time-lapse fluorescent sediment profile imaging sequence detailing the redistribution of pink luminophore tracer particles for the polychaete, Hediste diversicolor. Each frame = 5 minutes of elapsed time. (MOV)

Detailed guide on how to apply and parameterise the process-based, spatially explicit (2D) bioturbation simulation model detailed in this contribution. (DOC)

Bioturbation is one of the most widespread forms of ecological engineering and has significant implications for the structure and functioning of ecosystems, yet our understanding of the processes involved in biotic mixing remains incomplete. One reason is that, despite their value and utility, most mathematical models currently applied to bioturbat...

Community-structuring processes continue to be of great interest to plant ecologists, and plant spatial patterns have been linked to processes including disturbance, dispersal, environmental heterogeneity, and plant interactions. Under the assumption that the analysis of the spatial structure of plant communities can help to elucidate the type and...

There is an increasing recognition that the interplay between ecological and evolutionary processes shapes the genetic footprint of populations during and after range expansions. However, more complex ecological processes regularly considered within spatial ecology remain unexplored in models describing the population genetics of range expansion. I...

Morphological plasticity is a striking characteristic of plants in natural communities. In the context of foraging behavior particularly, root plasticity has been documented for numerous species. Root plasticity is known to mitigate competitive interactions by reducing the overlap of the individuals' rhizospheres. But despite its obvious effect on...

When investigating complex ecological dynamics at the population or community level, we necessarily need to abstract and aggregate ecological information. The way in which information is aggregated may be crucial for the outcome of the study. In this paper, we suggest that in addition to the traditional spatial, temporal and organizational levels,...

Question: Species composition during secondary succession is influenced by a number of factors, such as soil moisture, disturbance timing and surrounding vegetation. How does the importance of these factors change over the course of succession? Methods: We set up a full-factorial block design using molehills differing in (a) disturbance timing, (b)...

Drylands worldwide are exposed to a highly variable environment and face a high risk of degradation. The effects of global climate change such as altered precipitation patterns and increased temperature leading to reduced water availability will likely increase this risk. At the same time, an elevated atmospheric CO2 level could mitigate the effect...

The 2009 British Ecological Society's Annual Symposium entitled 'Facilitation in Plant Communities' was held at the University of Aberdeen, Scotland, from 20 to 22 April 2009. This was the first ever international meeting dedicated to the rapidly expanding field of facilitation. The aim of the symposium was to assess the current 'state-of-play' by...

Point pattern analyses such as the estimation of Ripley's K-function or the pair-correlation function g are commonly used in ecology to characterise ecological patterns in space. However, a major disadvantage of these methods is their missing ability to deal with spatial heterogeneity. A heterogeneous intensity of points causes a systematic bias in...

Competition is a key process in plant populations and communities. We thus need, if we are to predict the responses of ecological systems to environmental change, a comprehensive and mechanistic understanding of plant competition. Considering competition, however, only at the population level is not sufficient because plant individuals usually are...

1. Once neglected, the role of facilitative interactions in plant communities has received considerable attention in the last two decades, and is now widely recognized. It is timely to consider the progress made by research in this field. 2. We review the development of plant facilitation research, focusing on the history of the field, the relatio...

1. Once neglected, the role of facilitative interactions in plant communities has received considerable attention in the last two decades, and is now widely recognized. It is timely to consider the progress made by research in this field. 2. We review the development of plant facilitation research, focusing on the history of the field, the relation...

1 Interactions among plants strongly influence the structure and dynamics of plant populations and communities. However, most empirical studies of plant–plant interactions failed to make repeated measures of responses to neighbouring individuals and thereby neglected possible changes in interactions throughout the life history of the plants. 2 We t...