Biology subjects

Limberger, R.

Publications and source records attributed to Limberger, R..

3 recordsLinked to original sources

bioRxiv2024

Biodiversity increases the forecastability of species abundances in changing environments

Accurate forecasts of ecological dynamics are critical for ecosystem management and conservation, yet the drivers of forecastability are poorly understood. Environmental change and diversity are considered major challenges to ecological forecasting. This assumption, however, has never been tested experimentally because forecasts have high data requirements. In a long-term microcosm experiment, we manipulated species richness of 30 experimental protist communities and exposed them to constant or gradually decreasing light levels. We collected finely-resolved time series (123 sampling dates over 41 weeks) of species abundances, community biomass, and oxygen concentrations. We then employed data-driven forecasting methods to forecast these variables. We found that species richness and light had a weak interactive effect on forecasts of species abundances: richness tended to reduce forecast accuracy in constant light but tended to increase forecast accuracy in declining light. These effects could partially be explained by differences among time series in variability and autocorrelation. Forecasts of aggregate properties (community biomass, oxygen), however, were unaffected by richness and light, and were not more accurate than those of species abundances. Our forecasts were based on time series that were detrended and standardized. Since real-world forecasting applications require predictions at the original scale of the forecasted variable, it is important to note that the results were qualitatively identical when back-transforming the forecasts to the original scale. Taken together, we found no strong evidence that higher diversity results in lower forecastability. Rather, our results imply that promoting diversity could make populations more predictable when environmental conditions change. From a conservation and management perspective, our findings suggest that diversity conservation might have beneficial effects on decision-taking by increasing the forecastability of species abundances in changing environments.

ecology↗

bioRxiv2023

Response diversity in the context of multifarious environmental change

1.Response diversity represents the inter- and intraspecific trait variation in organismal responses to the environment. Assemblages composed of organisms displaying large variation in their response to the environment (that is, having high response diversity) are expected to have higher temporal stability of aggregate community and ecosystem properties such as ecosystem functioning (i.e., an insurance effect). Yet, response diversity is not commonly measured in empirical studies, and when it is measured, this is done in different ways. Moreover, most proposed measures of response diversity concern situations with only one driver of environmental change. Thus far, no specific approach exists to measure response diversity in the context of multiple simultaneously changing (multifarious) environmental drivers. Here, we propose a new method to empirically quantify response diversity in the context of multifarious environmental change. First, we illustrate this method using simulated data. Next, we reveal the role of the direction of environmental change in shaping response diversity when multiple drivers of environmental change fluctuate over time. We show that, when the direction of the environmental change is unknown (that is, there is no information or a priori expectation about how an environmental condition has changed or will change in future), we can quantify the potential response diversity for a given community under any possible future environmental change scenario. That is, we can estimate the potential response capacity of a system under a range of extreme or realistic environmental changes, capturing its complete insurance capacity, with utility for predicting future responses to even multifarious environmental change. Finally, we investigate the drivers of response diversity in a multifarious environmental change context, showing how response diversity depends on: 1) the diversity of species responses to each environmental variable considered, 2) the relative effect of each environmental variable on species performance, 3) the correlation between the diversity in species responses to different environmental variables, and 4) the mean temporal value of the environmental variable. In doing so, we take an important step towards understanding the insurance capacity of ecological communities exposed to multifarious environmental change.

ecology↗

bioRxiv2019

Adaptation and evolutionary rescue in a community context

Evolution might rescue populations from extinction in changing environments. Using experimental evolution with microalgae, we investigated if competition influences adaptation to an abiotic stressor, and vice versa, if adaptation to abiotic change influences competition. In a first set of experiments, we propagated monocultures of five species with and without increasing salt stress for ~180 generations. When assayed in monoculture, two of the five species showed signatures of adaptation, that is, lines with a history of salt stress had higher population growth rates at high salt than lines without prior exposure to salt. When assayed in mixtures of species, however, only one of these two species had increased population size at high salt, indicating that competition can alter how adaptation to abiotic change influences population dynamics. In a second experiment, we cultivated two species in monocultures and in pairs, with and without increasing salt. While we found no effect of competition on adaptation to salt, our experiment revealed that evolutionary responses to salt can influence competition. Specifically, one of the two species had reduced competitive ability in the no-salt environment after long-term exposure to salt stress. Collectively, our results highlight the complex interplay of adaptation to abiotic change and competitive interactions.

ecology↗