Sürdürülebilir Kalkınma Amaçları
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- Derleme MakaleAçık Erişim2026Microplastic Contamination in Amphibians and Reptiles: An Ecotoxicological Synthesis of Exposure, Mechanisms, and Risk Implications
Berber, Ahmet Ali; Akbulut, Cansu; Demir, Sefika Nur; Kurnaz, Muammer
Microplastic (MP) contamination has become a defining feature of twenty-first century environmental change, yet the toxicological and ecological consequences for amphibians and reptiles-two vertebrate classes already facing severe extinction pressures-remain fragmented across taxa, regions, and methodological traditions. Here, we synthesize field and experimental evidence from five continents to provide a taxonomically balanced, mechanistically grounded, and geographically explicit assessment of MP exposure, bioaccumulation, and toxicity in herpetofauna, drawing on a structured literature search in Web of Science, Scopus, and PubMed (January 2015-March 2026). Field detection rates of MPs in amphibian larvae range from 26% in conservatively screened Central European populations to 73-80% in anuran tadpoles from high-anthropogenic-pressure Anatolian catchments, with fibrous polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP) particles dominating the detected burden. Mechanistic evidence converges on oxidative stress cascades, hypothalamic-pituitary-thyroid axis disruption, gut and cutaneous microbiome dysbiosis, and compromised antiviral and antifungal immunity, with the latter potentially amplifying vulnerability to Batrachochytrium dendrobatidis and to ranavirus. Among reptiles, sea turtles display near-universal MP ingestion with documented maternal transfer to eggs; freshwater turtles, terrestrial squamates, and crocodilians remain critically understudied. Three structural asymmetries constrain current ecotoxicological risk characterization: taxonomic bias toward anurans and sea turtles, geographic bias toward the Global North, and experimental bias toward acute, supra-environmental laboratory exposures using pristine, single-polymer particles that fail to capture the chemical complexity of weathered field mixtures. We argue that MP burden may warrant consideration as a candidate stressor criterion within IUCN Red List assessments and within environmental risk assessment frameworks for freshwater and terrestrial biodiversity once a robust quantitative relationship between MP burden and demographic decline or population-level fitness has been established, and propose six hypothesis-driven research priorities: methodological standardization, reptile toxicokinetics, transgenerational epigenetics, MP-pathogen microbiome interactions and their translation into population viability models, temperature & times; MP interaction under climate warming, and population-genetic consequences of contemporary MP-driven selection, as the most tractable avenues for ecotoxicological progress and for the development of herpetofauna-specific risk characterization frameworks.
- MakaleAçık Erişim2026Citizen-Science Data Reveal Global Diversity Patterns in the Gecko Genus Hemidactylus
Kurnaz, Muammer; Berber, Ahmet Ali; Akbulut, Cansu
Understanding how species richness is distributed across space is a central goal of macroecology and biogeography. The gecko genus Hemidactylus ranks among the most speciose and broadly distributed of all squamate genera, with species spanning tropical and subtropical environments on most continents. Yet the large-scale structure of its diversity has rarely been examined at a global scale. Here we assembled georeferenced occurrence data for the genus from the Global Biodiversity Information Facility (GBIF Access data is 14 March 2026) and, following cleaning and quality control, retained 143,858 records covering 157 currently recognized species (approximately 79% of the genus) to characterize broad-scale biodiversity patterns. Our analyses addressed the latitudinal diversity gradient, the distribution of species range sizes, continental richness, spatial clustering of diversity, and regional beta diversity. Richness declined steadily from the tropics toward the poles, producing a pronounced latitudinal diversity gradient (Pearson r = −0.71, p < 0.001). A generalized additive model captured a strong non-linear association between latitude and richness (deviance explained = 98.1%), consistent with tropical regions acting as principal centers of diversity. Range-size distributions were markedly right-skewed, with the majority of species restricted to comparatively small areas; however, these estimates co-varied strongly with per-species sampling effort (r = 0.90) and warrant cautious interpretation. We found only a weak, marginally significant association between range size and latitudinal midpoint, offering little support for Rapoport’s rule in the genus. At the continental scale, Hemidactylus diversity was overwhelmingly concentrated in Afro-Asian tropical regions (Asia, 93 species; Africa, 66), whereas Europe and Oceania supported few species (four each). Spatial analyses indicated significant autocorrelation in richness (Moran’s I = 0.56, p < 0.001) and well-defined diversity hotspots in East Africa, the Indian subcontinent, and Southeast Asia, and regional beta diversity was high (Jaccard dissimilarity up to 0.97), reflecting pronounced faunal turnover among continents.