Biology subjects

Lembrechts, J. J.

Publications and source records attributed to Lembrechts, J. J..

3 recordsLinked to original sources

bioRxiv2024

Mountain roads across the globe significantly alter local soil microclimates

Mountain roads have repeatedly shown to host significantly different plant species communities compared to the adjacent natural vegetation. Besides the effect of propagule pressure, altered disturbance regime and soil processes, one of the reasons given for the strong influence of mountain roads on species distributions is a significantly altered microclimate in the roadside compared to the adjacent vegetation, a direct consequence of the altered disturbance regime. However, the microclimatic differences between roadside and natural vegetation have rarely been quantified, particularly lacking global analyses, hampering a better understanding of their importance for mountain biodiversity. In this study, we analysed in-situ measured soil temperatures along mountain roads in seven mountain regions across the globe, in order to assess the impact of mountain roads on a range of bioclimatic variables across the elevational gradient. Our results undeniably show the importance of roadsides as unique microhabitats, even in heterogeneous mountain environments. In most regions, roadside soils had warmer maxima (3.95 {+/-} 2.35{degrees}C warmer) and colder minima (0.85 {+/-} 1.11 {degrees}C colder) than the soil in the adjacent vegetation, with higher frost risks in winter. Therefore, we recommend future research to incorporate the notion that the local microclimates created by mountain roads could play a critical role in species redistributions in space and time.

ecology↗

bioRxiv2023

The drivers of dark diversity in the Scandinavian tundra are metric-dependent

AimDark diversity refers to the set of species that are not observed in an area but could potentially occur based on suitable local environmental conditions. In this paper, we applied both niche-based and co-occurrence-based methods to estimate the dark diversity of vascular plant species in the subarctic tundra. We then aimed to unravel the drivers explaining (1) why some locations were missing relatively more suitable species than others, and (2) why certain plant species were more often absent from suitable locations than others. LocationThe Scandinavian tundra around Abisko, northern Sweden. MethodsWe calculated the dark diversity in 107 plots spread out across four mountain trails using four different methods. Two niche-based (Beals index and hypergeometric method) and two co-occurrences-based (climatic niche model and climatic niche model followed by species-specific threshold) methods. This was then followed by multiple generalized linear mixed models and general linear models to determine which habitat characteristics and species traits contributed most to the dark diversity. ResultsThe study showed a notable divergence in the predicted drivers of dark diversity depending on the method used. Nevertheless, we can conclude that plot-level dark diversity was generally 18% higher in areas at low elevations and 30% and 10% higher in areas with a low species richness or low levels of habitat disturbance, respectively. ConclusionOur findings call for caution when interpreting statistical findings of dark diversity estimates. Even so, all analyses point towards an important role for natural processes such as competitive dominance as main driver of the spatial patterns found in dark diversity in the northern Scandes.

ecology↗

bioRxiv2020

Once upon a time in the south: local drivers of plant invasion in the harsh sub-Antarctic islands

AimHere, we aim to: (i) investigate the local effect of environmental and human-related factors on alien plant invasion in sub-Antarctic islands; (ii) explore the relationship between alien species features and their dependence on anthropogenic propagule pressure; and (iii) unravel key traits conferring invasiveness in the sub-Antarctic. LocationPossession Island, Crozet archipelago (French sub-Antarctic islands). TaxonNon-native vascular plants (Poaceae, Caryophyllaceae, Juncaceae). MethodsSingle-species distribution models were used to explore the effect of high-resolution topoclimatic and human-related variables on the occurrence of six of the most aggressive alien plants colonizing French sub-Antarctic islands. Furthermore, the interaction between alien species traits and their response to anthropogenic propagule pressure was analysed by means of a multi-species distribution model. This allowed identifying the features of species that were associated to low dependence on human-assisted introductions, and were thus potentially more invasive. ResultsWe observed two main invasion patterns: low-spread species strongly dependent on anthropogenic propagule pressure and high-spread species limited mainly by harsh climatic conditions. Differences in invasiveness across species mostly related to their residence time, life history and plant height, with older introductions, perennial and low-stature species being more invasive. Main conclusionsThe availability of high-resolution data improved our understanding of the role of environmental and human-related factors in driving alien species distribution on sub-Antarctic islands. At the same time, the identification of alien species features conferring invasiveness may help anticipating future problematic invasions.

ecology↗