Climate warming and land-use change are reshuffling the distribution of wild organisms on a global scale. Some species may expand their ranges and colonize new regions, which may greatly affect ecological interactions among pre-existing species and colonizers. In the last decades, such processes have originated a unique condition of sympatry among three Eurasian small Falco species (common kestrel F. tinnunculus, lesser kestrel F. naumanni, red-footed falcon F. vespertinus) in the intensively cultivated farmland habitats of the Po Plain (Northern Italy). This provides an excellent opportunity to investigate patterns of spatial niche overlap during the initial phases of the establishment of sympatry. To investigate spatial niche overlap of the three falcon species, we relied on Environmental Niche Models (ENMs) based on widespread breeding occurrence data obtained through field surveys and citizen science programs (during the 2018–2020 period). ENMs were based on bioclimatic and land-use variables in an ensemble modelling framework. We estimated species-specific relative contributions of each climatic and land-use variable and its response curves effect. Eventually, we generated spatial correlation maps of the potential species’ distributions to derive spatially-explicit predictions of potential co-occurrence areas among the three species. Overall, eco-climatic determinants of the distribution of lesser kestrel and red-footed falcon were similar, resulting in a strong association with intensive arable lands and dry continental climate. Consistently, we found a high spatial correlation between the suitability maps of the two species, with highly suitable areas located in the Central-Eastern area of the Po Plain, corresponding to the core range of both species. Conversely, the common kestrel emerged as a habitat generalist and was widely distributed throughout the Po Plain. Our findings suggest that the recent sympatry between lesser kestrels and red-footed falcons in the Po Plain may promote ecological interactions and intra-guild competition.
Habitat selection in animals is a fundamental ecological process with key conservation implications. Assessing habitat selection in endangered species and populations occupying the extreme edges of their distribution range, or living in highly anthropized landscapes, may be of particular interest as it may provide hints to mechanisms promoting potential range expansions. We assessed second- and third-order foraging habitat selection in the northernmost European breeding population of the lesser kestrel (Falco naumanni), a migratory falcon of European conservation interest, by integrating results obtained from 411 direct observations with those gathered from nine GPS-tracked individuals. The study population breeds in the intensively cultivated Po Plain (northern Italy). Direct observations and GPS data coincide in showing that foraging lesser kestrels shifted their habitat preferences through the breeding cycle. They positively selected alfalfa and other non-irrigated crops during the early breeding season, while winter cereals were selected during the nestling-rearing phase. Maize was selected during the early breeding season, after sowing, but significantly avoided later. Overall, vegetation height emerged as the main predictor of foraging habitat selection, with birds preferring short vegetation, which is likely to maximise prey accessibility. Such a flexibility in foraging habitat selection according to spatio-temporal variation in the agricultural landscape determined by local crop management practices may have allowed the species to successfully thrive in one of the most intensively cultivated areas of Europe. In the southeastern Po Plain, the broad extent of hay and non-irrigated crops is possibly functioning as a surrogate habitat for the pseudo-steppe environment where most of the European breeding population is settled, fostering the northward expansion of the species in Europe. In intensive agricultural landscapes, the maintenance of alfalfa and winter cereals crops and an overall high crop heterogeneity (deriving from crop rotation) is fundamental to accommodate the ecological requirements of the species in different phases of its breeding cycle.
The study of the environmental features affecting amphibian communities is a priority task for addressing effective conservation initiatives. In the southern edge of the Apennines (Sila Massif, Calabria Region, Italy), we surveyed the distribution of amphibians in lotic freshwater habitats (eight rivers, 17 sampling stations, 87 transects) and recorded nine environmental variables, including the occurrence of potential predators (fish and Eurasian otter Lutra lutra), potentially affecting the distribution and breeding success of amphibian species. A total of seven amphibian species was recorded (75.9% of transects). Fish occurred in all rivers while the otter was found in four rivers (Amato, Lese, Neto, and Savuto). Illuminance and bank heterogeneity were the main factors affecting amphibian reproduction, while neither otter nor fish presence showed significant effects on the amphibian community. Overall, habitat complexity and coevolution history seemed to shape the distribution of amphibians and their breeding sites, while the ongoing recolonization of the study area by the otter is expected to have a negligible impact on the richness of the amphibian community.
12 March 2025 in Proceedings Of The Royal Society B-Biological Sciences
Homing pigeons rely on familiar landscape features in learning a visual map, which is orchestrated by the forebrain visual Wulst and hippocampus. Recent global positioning system tracking studies showed that pigeons with damage to the visual Wulst or hippocampus exhibited a still poorly understood, persistent oscillatory flight behaviour, unlike intact pigeons whose oscillations decrease with experience. To evaluate whether landscape heterogeneity influences the extent of these oscillations, we compared the flight behaviour of both intact and Wulst-lesioned pigeons when flying over the sea versus land. Regardless of treatment, pigeons exhibited less oscillatory flight behaviour over the homogeneous landscape of the sea. Further releases from familiar and unfamiliar sites tested whether oscillatory flight behaviour may be influenced by the level of familiarity with the landscape. Indeed, intact pigeons reduced their oscillatory behaviour as landscape familiarity increased. In contrast, Wulst-damaged pigeons persisted in displaying robust oscillatory flight behaviour regardless of the level of landscape familiarity, suggesting that previously experienced landscapes remained relatively unfamiliar to them. The data support the hypothesis that oscillatory flight behaviour reflects active visual scanning, most pronounced over novel, heterogeneous landscapes, contributing to visual map learning. Further, the data suggest a crucial role of the forebrain Wulst for such learning.
Artificial breeding structures, such as nestboxes, can potentially influence the population size and conservation status of bird species relying on heavily human‐modified environments such as agroecosystems and urban areas. However, the effectiveness of these interventions may vary, as artificial structures could attract individuals to suboptimal breeding sites, potentially reducing breeding success compared to natural nesting sites and resulting in ecological traps. European populations of the Lesser Kestrel Falco naumanni , a secondary cavity‐nesting raptor, have greatly benefitted from extensive provisioning of artificial nestboxes in recent decades. However, the long‐term conservation effectiveness of such efforts may be jeopardized because of recent changes in local climatic conditions, with nestboxes becoming unsuitable under climate warming as nest temperatures become too high, exposing developing embryos and nestlings to lethal hyperthermia. We assessed variation in nest temperature and breeding success between naturally available nest‐cavities (natural nests) and nestboxes in two Italian Lesser Kestrel populations settled in different climatic zones (Po Plain, subcontinental; Matera, semi‐arid). In both areas, natural nests were ~5°C cooler than nestboxes. In the Po Plain, nestling survival was substantially lower in natural nests (44%) than in nestboxes (96%), whereas the opposite was the case in Matera (92% vs 45%). In Matera, frequent heatwaves led to very high temperatures (>44°C) inside nestboxes, which in turn resulted in lethal hyperthermia and a substantial reduction in nestling survival, while this was not the case in natural nests. In contrast, nestbox temperatures in the Po Plain were always below critical values, and nestling predation was lower compared to natural nests. These findings highlight that the appropriateness of nestbox provisioning should be carefully evaluated on a case‐by‐case basis, and that considering thermal safety, climate resilience and predation risk is crucial when designing and building artificial nest structures to ensure their long‐term conservation effectiveness.