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The road to opportunities: landscape change promotes body-size divergence in a highly mobile species.

ABSTRACT: Landscape change provides a suitable framework for investigating population-level responses to novel ecological pressures. However, relatively little attention has been paid to examine the potential influence of landscape change on the geographic scale of population differentiation. Here, we tested for morphological differentiation of red-necked nightjars Caprimulgus ruficollis breeding in a managed property and a natural reserve situated less than 10 km apart. At both sites, we also estimated site fidelity over 5 years and quantified the potential foraging opportunities for nightjars. Breeding birds in the managed habitat were significantly larger in size-as indexed by keel length-than those in the natural one. However, there were no significant differences in wing or tail length. Immigration from neighboring areas was almost negligible and, furthermore, no individual (out of 1130 captures overall) exchanged habitats between years, indicating strong site fidelity. Food supply for nightjars was equally abundant in both habitats, but the availability of foraging sites was remarkably higher in the managed property. As a result, nightjars-particularly fledglings-in the latter habitat benefited from increased foraging opportunities in relation to those in the natural site. It seems likely that the fine-scale variation in nightjar morphology reflects a phenotypic response to unequal local conditions, since non-random dispersal or differential mortality had been determined not to be influential. High site fidelity appears to contribute to the maintenance of body-size differences between the two habitats. Results from this nightjar population highlight the potential of human-induced landscape change to promote population-level responses at exceedingly small geographic scales.

SUBMITTER: Camacho C

PROVIDER: S-EPMC5804134 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

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The road to opportunities: landscape change promotes body-size divergence in a highly mobile species.

Camacho Carlos C Sáez Pedro P Sánchez Sonia S Palacios Sebastián S Molina Carlos C Potti Jaime J

Current zoology 20160210 1

Landscape change provides a suitable framework for investigating population-level responses to novel ecological pressures. However, relatively little attention has been paid to examine the potential influence of landscape change on the geographic scale of population differentiation. Here, we tested for morphological differentiation of red-necked nightjars <i>Caprimulgus ruficollis</i> breeding in a managed property and a natural reserve situated less than 10 km apart. At both sites, we also esti ...[more]

PMID: 29491885

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Project description:BackgroundLittle is known about the long-term patterns of body size evolution in Crocodylomorpha, the >?200-million-year-old group that includes living crocodylians and their extinct relatives. Extant crocodylians are mostly large-bodied (3-7?m) predators. However, extinct crocodylomorphs exhibit a wider range of phenotypes, and many of the earliest taxa were much smaller (<?1.2?m). This suggests a pattern of size increase through time that could be caused by multi-lineage evolutionary trends of size increase or by selective extinction of small-bodied species. Here, we characterise patterns of crocodylomorph body size evolution using a model fitting-approach (with cranial measurements serving as proxies). We also estimate body size disparity through time and quantitatively test hypotheses of biotic and abiotic factors as potential drivers of crocodylomorph body size evolution.ResultsCrocodylomorphs reached an early peak in body size disparity during the Late Jurassic, and underwent an essentially continual decline since then. A multi-peak Ornstein-Uhlenbeck model outperforms all other evolutionary models fitted to our data (including both uniform and non-uniform), indicating that the macroevolutionary dynamics of crocodylomorph body size are better described within the concept of an adaptive landscape, with most body size variation emerging after shifts to new macroevolutionary regimes (analogous to adaptive zones). We did not find support for a consistent evolutionary trend towards larger sizes among lineages (i.e., Cope's rule), or strong correlations of body size with climate. Instead, the intermediate to large body sizes of some crocodylomorphs are better explained by group-specific adaptations. In particular, the evolution of a more aquatic lifestyle (especially marine) correlates with increases in average body size, though not without exceptions.ConclusionsShifts between macroevolutionary regimes provide a better explanation of crocodylomorph body size evolution on large phylogenetic and temporal scales, suggesting a central role for lineage-specific adaptations rather than climatic forcing. Shifts leading to larger body sizes occurred in most aquatic and semi-aquatic groups. This, combined with extinctions of groups occupying smaller body size regimes (particularly during the Late Cretaceous and Cenozoic), gave rise to the upward-shifted body size distribution of extant crocodylomorphs compared to their smaller-bodied terrestrial ancestors.

Project description:Lewy body dementia (LBD), including dementia with Lewy bodies and Parkinson's disease dementia, affects over a million people in the USA and has a substantial impact on patients, caregivers, and society. Symptomatic treatments for LBD, which can include cognitive, neuropsychiatric, autonomic, sleep, and motor features, are limited with only two drugs (cholinesterase inhibitors) currently approved by regulatory agencies for dementia in LBD. Clinical trials represent a top research priority, but there are many challenges in the development and implementation of trials in LBD. To address these issues and advance the field of clinical trials in the LBDs, the Lewy Body Dementia Association formed an Industry Advisory Council (LBDA IAC), in addition to its Research Center of Excellence program. The LBDA IAC comprises a diverse and collaborative group of experts from academic medical centers, pharmaceutical industries, and the patient advocacy foundation. The inaugural LBDA IAC meeting, held in June 2019, aimed to bring together this group, along with representatives from regulatory agencies, to address the topic of optimizing the landscape of LBD clinical trials. This review highlights the formation of the LBDA IAC, current state of LBD clinical trials, and challenges and opportunities in the field regarding trial design, study populations, diagnostic criteria, and biomarker utilization. Current gaps include a lack of standardized clinical assessment tools and evidence-based management strategies for LBD as well as difficulty and controversy in diagnosing LBD. Challenges in LBD clinical trials include the heterogeneity of LBD pathology and symptomatology, limited understanding of the trajectory of LBD cognitive and core features, absence of LBD-specific outcome measures, and lack of established standardized biologic, imaging, or genetic biomarkers that may inform study design. Demands of study participation (e.g., travel, duration, and frequency of study visits) may also pose challenges and impact trial enrollment, retention, and outcomes. There are opportunities to improve the landscape of LBD clinical trials by harmonizing clinical assessments and biomarkers across cohorts and research studies, developing and validating outcome measures in LBD, engaging the patient community to assess research needs and priorities, and incorporating biomarker and genotype profiling in study design.

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The road to opportunities: landscape change promotes body-size divergence in a highly mobile species.

Publications

The road to opportunities: landscape change promotes body-size divergence in a highly mobile species.

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