Publications by authors named "Marcel Rejmanek"

Changes in climate and land use are the most often mentioned factors responsible for the current decline in species diversity. To reduce the effect of these factors, we need reliable predictions of future species distributions. This is usually done by utilizing species distribution models (SDMs) based on expected climate.

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Article Synopsis
  • During the Anthropocene, human activities are significantly altering the Earth’s ecosystems, leading to accelerated plant extinctions, particularly in biodiversity hotspots.
  • A comprehensive dataset covering over 300 years reveals that extinction rates in these areas are much higher than historical averages, with agriculture and urbanization as major causes.
  • Interestingly, while coldspots show lower overall extinction rates, they are losing more unique plant species compared to hotspots, indicating uneven impacts on global biodiversity.
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Identifying potentially invasive species and preventing their introduction and establishment are of critical importance in invasion ecology and land management. Although an extensive body of research has been dedicated to identifying traits that confer invasiveness, our current knowledge is still often inconclusive due to limitations in geographic extent and/or scope of traits analyzed. Here, using a comprehensive set of 45 traits, we performed a case study of invasive traits displayed by exotic woody plants in the United States (U.

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Background And Aims: Aesculus L. (horse chestnut, buckeye) is a genus of 12-19 extant woody species native to the temperate Northern Hemisphere. This genus is known for unusually large seeds among angiosperms.

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Premise Of The Study: Revealing biological differences between invasive and noninvasive species is essential for predicting species' distribution changes with global environmental change. While most research has focused on differences between invasive and noninvasive species under favorable conditions using herbaceous species, invasive woody angiosperms are also of great ecological concern. Our study focused on how growth and allocation may change for invasive and noninvasive, mediterranean, woody angiosperms under future conditions caused by global change, specifically increased nitrogen deposition and drought.

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Broad-scale animal diversity patterns have been traditionally explained by hypotheses focused on climate-energy and habitat heterogeneity, without considering the direct influence of vegetation structure and composition. However, integrating these factors when considering plant-animal correlates still poses a major challenge because plant communities are controlled by abiotic factors that may, at the same time, influence animal distributions. By testing whether the number and variation of plant community types in Europe explain country-level diversity in six animal groups, we propose a conceptual framework in which vegetation diversity represents a bridge between abiotic factors and animal diversity.

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A growing number of studies seeking generalizations about the impact of plant invasions compare heavily invaded sites to uninvaded sites. But does this approach warrant any generalizations? Using two large datasets from forests, grasslands and desert ecosystems across the conterminous United States, we show that (i) a continuum of invasion impacts exists in many biomes and (ii) many possible species-area relationships may emerge reflecting a wide range of patterns of co-occurrence of native and alien plant species. Our results contradict a smaller recent study by Powell et al.

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Some alien species cause substantial impacts, yet most are innocuous. Given limited resources, forecasting risks from alien species will help prioritise management. Given that risk assessment (RA) approaches vary widely, a synthesis is timely to highlight best practices.

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Scatter-hoarding animals spread out cached seeds to reduce density-dependent theft of their food reserves. This behaviour could lead to directed dispersal into areas with lower densities of conspecific trees, where seed and seedling survival are higher, and could profoundly affect the spatial structure of plant communities. We tested this hypothesis with Central American agoutis and Astrocaryum standleyanum palm seeds on Barro Colorado Island, Panama.

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The extent to which environmental heterogeneity can account for tree species coexistence in diverse ecosystems, such as tropical rainforests, is hotly debated, although the importance of spatial variability in contributing to species co-existence is well recognized. Termites contribute to the micro-topographical and nutrient spatial heterogeneity of tropical forests. We therefore investigated whether epigeal termite mounds could contribute to the coexistence of plant species within a 50 ha plot at Pasoh Forest Reserve, Malaysia.

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Introduced species have the potential to impact processes central to the organization of ecological communities. Although hundreds of nonnative plant species have naturalized in the United States, only a small percentage of these have been studied in their new biotic communities. Their interactions with resident (native and introduced) bird species remain largely unexplored.

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Seed predation and seed dispersal can have strong effects on early life history stages of plants. These processes have often been studied as individual effects, but the degree to which their relative importance co-varies with seed predator abundance and how this influences seed germination rates is poorly understood. Therefore, we used a combination of observations and field experiments to determine the degree to which germination rates of the palm Astrocaryum mexicanum varied with abundance of a small mammal seed predator/disperser, Heteromys desmarestianus, in a lowland tropical forest.

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Despite their potential to provide mechanistic explanations of rates of seed dispersal and seed fate, the functional and numerical responses of seed predators have never been explicitly examined within this context. Therefore, we investigated the numerical response of a small-mammal seed predator, Heteromys desmarestianus, to disturbance-induced changes in food availability and evaluated the degree to which removal and fate of seeds of eight tree species in a lowland tropical forest in Belize were related to the functional response of H. desmarestianus to varying seed densities.

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We studied 29 pine (Pinus) species to test the hypothesis that invasive species in disturbed habitats have distinct attributes. Seedling relative growth rate (RGR) and measures of invasiveness were positively associated across species as well as within phylogenetically independent contrasts. High RGR, small seed masses, and short generation times characterize pine species that are successful invaders in disturbed habitats.

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Plant host species is considered an important factor influencing ectomycorrhizal (EM) communities. To gain insights into the role of host species in structuring EM communities, EM communities on sympatric oak (Quercus) species were compared in the Sierra Nevada foothills of California. Using molecular methods (polymerase chain reaction, cloning, restriction fragment length polymorphism and DNA sequencing), EM fungi on roots of deciduous Quercus douglasii and evergreen Quercus wislizeni trees were identified from 64 soil cores.

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Understanding causal factors of exotic species invasions is important not only for prevention and prioritizing control efforts, but also for providing valuable insights into the underlying biology of contrasting life-history strategies. In seedling growth analyses, invasive woody species were compared with less-invasive woody species commonly cultivated in California using phylogenetically corrected procedures (12 phylogenetically independent contrasts). Invasive species were hypothesized to have higher seedling relative growth rates (RGRs) and specific leaf areas (SLAs) than did related less-invasive species.

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Genome size has been suggested to be a fundamental biological attribute in determining life-history traits in many groups of organisms. We examined the relationships between pine genome sizes and pine phylogeny, environmental factors (latitude, elevation, annual rainfall), and biological traits (latitudinal and elevational ranges, seed mass, minimum generation time, interval between large seed crops, seed dispersal mode, relative growth rate, measures of potential and actual invasiveness, and level of rarity). Genome sizes were determined for 60 pine taxa and then combined with published values to make a dataset encompassing 85 species, or 70% of species in the genus.

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Glasshouse competition experiments with Hydrilla verticillata (L.f.) Royle indicate that plants grown from turions are weaker competitors than those grown from tubers, when compared to the widely distributed macrophyte, Potamogeton pectinatus L.

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The relationship between fecundity and long-term adult fluctuations of 29 temperate noctuid moths was investigated and is explained in terms of the r- and K-selection strategies. The potential population growth rate per year (PGR) and the "rate of return to equilibrium" (sensu Pimm 1982) have been calculated and correlated with generation-to-generation fluctuations. A highly significant correlation was found between PGR and the coefficient of generation-to-generation variation.

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A number of indices of community dissimilarity based on the species diversity measures have been proposed during the last three decades (Margalef 1956, 1957; Kohn 1959; MacArthur 1965; Horn 1966; Glowaciński and Järvinen 1975; Järvinen and Väisänen 1976). Each of them is measuring the wrong quantity if the value of diversity in a particular sample is higher than in a pooled sample. Simple corrections are suggested to avoid this shortcoming.

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