Biology subjects

Laanisto, L.

Publications and source records attributed to Laanisto, L..

3 recordsLinked to original sources

bioRxiv2023

Habitat amount, temperature and biotic interactions drive community structure, life-history traits, and performance traits of cavity-nesting bees and wasps and their natural enemies in cities

O_LIUrban ecosystems are associated with socio-ecological conditions that can filter and promote taxa. However, the strength of the effect of ecological filtering on biodiversity could vary among biotic and abiotic factors. Here, we investigate the effects of habitat amount, temperature, and host-enemy biotic interactions in shaping communities of cavity-nesting bees and wasps (CNBW) and their natural enemies. C_LIO_LIWe installed trap-nests in 80 sites distributed along urban intensity gradients in 5 European cities (Antwerp, Paris, Poznan, Tartu and Zurich). We quantified the species richness and abundance of CNBW hosts and their natural enemies, as well as two performance traits (survival and parasitism) and two life-history traits (sex ratio and number of offspring per nest for the hosts). We analysed the importance of the abiotic and biotic variables using generalized linear models and multi-model inference. C_LIO_LIWe found that habitat amount and temperature were the main drivers of CNBW host responses, with larger habitat amounts resulting in higher species richness and abundance, and a larger total number of brood cells per nest for both bees and wasps, as well as a larger probability of survival for bees. Conversely, higher local temperatures decreased species richness, abundance, survival rate, number of brood cells per nest, and proportion of females in CNBW hosts. C_LIO_LIBiotic interactions with natural enemies shaped wasp species richness, with higher levels of parasitism resulting in more wasp species. Similarly, our results showed direct density-dependence between CNBW hosts and their natural enemies. C_LIO_LIOverall, our study highlights the importance of habitat amount and temperature in shaping urban food webs, through direct effects on hosts responses and the subsequent consequences for their natural enemies. As cities prepare to tackle the future consequences of global change, strategies that make it possible to maintain available habitat and mitigate urban overheating emerge as a key urban adaptation for biodiversity conservation. C_LI

ecology↗

bioRxiv2021

An updated framework to account for inter-individual variability when quantifying phenotypic variation

O_LIIn trait-based ecology, phenotypic variation (PVar) is often quantified with measures that express average differences between populations standardized in the range 0-1. A major problem with these measures is that they disregard the within-population trait variability. In addition, most of these measures cannot be decomposed across scales. This can alter their interpretation, thus limiting their applicability. C_LIO_LITo overcome these problems, we propose a new measure, the Phenotypic Dissimilarity Index (PhD) that is insensitive to the within-population interindividual trait variability. Likewise, PhD can be used to quantify PVar between individuals in a population while accounting for the PVar within individuals. C_LIO_LIUsing simulated and real data, we showed that PhD index correctly quantifies PVar when the within-population trait variability is not negligible, as in many ecological studies. By accounting for within-population trait variability, the PhD index generally provides a more parsimonious quantification of PVar across an environmental gradient compared to other estimators. C_LIO_LITraits sampled within a species have an inherent variability. Accounting for such variability is essential to understand species phenotypic responses to environmental cues. As such, the PhD index will provide ecologists with an asset to reliably quantify and compare PVar within and between species across environmental gradients at different scales. We also provide an R function to calculate the PhD index. C_LI

ecology↗

bioRxiv2021

The cold-drought tolerance trade-off in temperate woody plants constrains range size, but not range filling

Interspecific differences in plant species ranges are shaped by complex mechanistic interactions, which have so far remained largely beyond the reach of comprehensive models and explanations. Previous attempts to find underlying mechanisms by examining physiological tolerances to cold and heat separately have yielded contradictory results. Here we test the hypothesis that, instead of examining single stressors, abiotic stress tolerance syndromes that involve trade-offs between multiple abiotic stressors (namely drought, cold, waterlogging and shade), will provide reliable explanations. We compiled a dataset of actual range size and range filling (the ratio between actual and potential species range) as range metrics for 331 temperate woody plants species from Europe and North America. Tolerance syndromes were expressed as two PCA axes. One axis reflects a drought-cold/waterlogging tolerance trade-off (cold/wet-drought trade-off), the second axis represents a shade tolerance spectrum. Phylogenetic generalized linear mixed models were used to model the range metric-tolerance axes relationships using latitude as an additional main effect, and phylogeny and plant functional type as random effects. Actual range scaled negatively with the cold/wet-drought tolerance trade-off axis, mostly independently of latitude and continent. Thus, cold/wet-tolerant species had the largest ranges and drought tolerant species the smallest. The sign (-) of the relationship was independent of phylogeny and plant functional type. In contrast, range filling depended on latitude. However, deciduous and evergreen species displayed different distributions of range metrics and tolerance syndromes. No significant relationships with the shade tolerance spectrum were found. Our findings demonstrate that the cold/wet-drought trade-off partly explains interspecific range size differences. However, this trade-off did not explain range filling. We also showed that fundamental adaptations of species also significantly influence range sizes - stress avoidance through the deciduous habit also explained interspecific differences in range size.

ecology↗