HETEROLOCHA LAMINARIA (HERRICH-SCHÄFFER, 1852) (LEPIDOPTERA: GEOMETRIDAE) — A NEW SPECIES FOR THE UKRAINIAN FAUNA

The first records of Heterolocha laminaria (Herrich-Schäffer, 1852) (Lepidoptera: Geometridae) in Ukraine are presented. Until the recent past, the European registrations of H. laminaria had been only reported from Rostov Region of Russia. New records were made at several localities within Dnipropetrovsk, Zaporizhzhia, Odesa and Poltava regions, in Southern, South-Western, South-Eastern and Central Ukraine. These findings were revealed from mid-June to mid-August in various habitat types: steppes, artificial deciduous and mixed forests, agrocenosis. The current records significantly shift westward the range limits of H. la­mi­na­ria. Thus, a newly-discovered locality in Savran Forest is the westernmost point in the entire species range. Most likely the westward expansion of this species has occurred in recent decades. The habitats, adults, and male genitalia of H. laminaria are illustrated.

Environment-dependent expression of mutational load and species' range limits

Theoretical and empirical research on the causes of species' range limits suggests the contribution of several intrinsic and extrinsic factors, with potentially complex interactions among them. An intrinsic factor proposed by recent theory is mutational load increasing towards range edges because of genetic drift. Furthermore, environmental quality may erode towards range edges and enhance the expression of load. Here we tested whether the expression of mutational load associated with range limits in the North American Arabidopsis lyrata is enhanced under stressful conditions, by comparing the performance of within- versus between-population crosses at common garden sites across the species' distribution and beyond. Heterosis, reflecting the expression of load, increased with heightened estimates of genomic load and with environmental stress caused by warming, but the interaction was not significant. We conclude that range-edge populations suffer from a twofold genetic Allee effect caused by increased mutational load and stress-dependent load linked to general heterozygote deficiency, but no synergistic effect between them.

Distribution and habitat use of the Madagascar Peregrine Falcon: first estimates for area of habitat and population size

Accurately demarcating species distributions has long been at the core of ecology. Yet our understanding of the factors limiting species range limits is incomplete, especially for tropical species in the Global South. Human-driven threats to the survival of many taxa are increasing, particularly habitat loss and climate change. Identifying distributional range limits of at-risk and data-limited species using Species Distribution Models (SDMs) can thus inform spatial conservation planning to mitigate these threats. The Madagascar Peregrine Falcon (Falco peregrinus radama) is the resident sub-species of the Peregrine Falcon complex distributed across Madagascar, Mayotte, and the Comoros Islands. Currently, there are significant knowledge gaps regarding its distribution, habitat preferences and population size. Here, we use point process regression models and ordination to identify Madagascar Peregrine Falcon environmental range limits and propose a population size estimate based on inferred habitat. From our models, the core range of the Madagascar Peregrine Falcon extends across the central upland plateau of Madagascar with a patchier range across coastal and low-elevation areas. Range-wide habitat use indicated that the Madagascar Peregrine Falcon prefers areas of high elevation and aridity, coupled with high vegetation heterogeneity and > 95 % herbaceous landcover, but generally avoids areas of > 30 % cultivated land and > 10 % mosaic forest. Based on inferred high-class habitat, we estimate this habitat area could potentially support a population size ranging between 150-300 pairs. Following International Union for Conservation of Nature Red List guidelines, we recommend this sub-species be classed as Vulnerable, due to its small population size. Despite its potentially large range, the Madagascar Peregrine has specialized habitat requirements and would benefit from targeted conservation measures based on spatial models in order to maintain viable populations.

Does pollen limitation limit plant ranges? Evidence and implications

Range limits often involve declines in sexual reproduction, reducing fitness, dispersal, and adaptive potential at range edges. For plants, sexual reproduction is frequently limited by inadequate pollination. While case studies show that pollen limitation can limit plant distributions, the extent to which pollination commonly declines toward plant range edges is unknown. Here, we leverage global databases of pollen-supplementation experiments and plant occurrence data to test whether pollen limitation increases toward plant range edges, using a phylogenetically controlled meta-analysis. While there was significant pollen limitation across studies, we found little evidence that pollen limitation increases toward plant range edges. Pollen limitation was not stronger toward the tropics, nor at species' equatorward vs poleward range limits. Meta-analysis results are consistent with results from targeted experiments, in which pollen limitation increased significantly toward only 14% of 14 plant range edges, suggesting that pollination contributes to range limits less often than do other interactions. Together, these results suggest pollination is one of the rich variety of potential ecological factors that can contribute to range limits, rather than a generally important constraint on plant distributions.

Increasing temporal variance leads to stable species range limits

What prevents populations of a species from adapting to the novel environments outside the species' geographic distribution? Previous models highlighted how gene flow across spatial environmental gradients determines species expansion vs. extinction and the location of species range limits. However, space is only one of two axes of environmental variation — environments also vary in time, and we know temporal environmental variation has important consequences for population demography and evolution. We used an individual based evolutionary model to explore how temporal stochasticity in environmental conditions influences the spread of populations across a spatial environmental gradient. We find that temporal stochasticity greatly alters our predictions for range dynamics compared to temporally static environments. When temporal variance is equal across the landscape, the fate of species (expansion vs. extinction) is determined by the interaction between the degree of temporal autocorrelation in environmental fluctuations and the steepness of the spatial environmental gradient. When the magnitude of temporal variance changes across the landscape, stable range limits form where this variance becomes large enough to prevent local population adaptation and persistence. These results illustrate the pivotal influence of temporal stochasticity on the likelihood of populations colonizing novel habitats and the location of species range limits.

Range extension of the Central American Red Brocket, Mazama temama (Kerr, 1792) (Artiodactyla, Cervidae), in Colombia

Mazama temama (Kerr, 1792) is a representative species of the northern Neotropics, but the geographic range limits for this species remain unclear. We report the southernmost record of M. temama from the southwestern Colombian Andes, increasing the previously known range of this species by more than 300 km. We obtained a cytochrome gene sequence (849 bp) which is 95% identical to samples from Mexico. This record raises the need for extensive sampling to obtain more complete information about the distribution of M. temama in northern Colombia.