Data from: Reliable effective number of breeders/adult census size ratios in seasonal-breeding species: opportunity for integrative demographic inferences based on capture-mark-recapture data and multilocus genotypes

The ratio of the effective number of breeders (Nb) to the adult census size (Na), Nb/ Na, approximates the departure from the standard capacity of a population to maintain genetic diversity in one reproductive season. This information is relevant for assessing population status, understanding evolutionary processes operating at local scales and unraveling how life-history traits affect these processes. However, our knowledge on Nb/Na ratios in nature is limited because estimation of both parameters is challenging. The sibship frequency (SF) method is adequate for reliable Nb estimation because it is based on sibship and parentage reconstruction from genetic marker data, thereby providing demographic inferences that can be compared with field-based information. In addition, capture-mark-recapture (CMR) robust design methods are well suited for Na estimation in seasonal-breeding species. We used tadpole genotypes of three pond-breeding amphibian species (Epidalea calamita, Hyla molleri and Pelophylax perezi, n = 73-96 single-cohort tadpoles / species genotyped at 15-17 microsatellite loci) and candidate parental genotypes (n = 94-300 adults / species) to estimate Nb by the SF method. To assess the reliability of Nb estimates, we compared sibship and parentage inferences with field-based information and checked for the convergence of results in replicated subsampled analyses. Finally, we used CMR data from a 6-year monitoring program to estimate annual Na in the three species and calculate the Nb/Na ratio. Reliable ratios were obtained for E. calamita (Nb/Na = 0.18-0.28) and P. perezi (0.5), but in H. molleri Na could not be estimated and genetic information proved insufficient for reliable Nb estimation. Integrative demographic studies taking full advantage of SF and CMR methods can provide accurate estimates of the Nb/Na ratio in seasonal-breeding species. Importantly, the SF method provides results that can be readily evaluated for reliability. This represents a good opportunity for obtaining robust demographic inferences with wide applications for evolutionary and conservation research.

有效繁殖个体数（effective number of breeders, Nb）与成年种群普查量（adult census size, Na）的比值Nb/Na，可近似反映种群在单个繁殖季内维持遗传多样性的能力与理论基准的偏差程度。该指标对于评估种群现状、解析局域尺度下的进化过程，以及阐明生活史性状如何影响这些过程具有重要意义。然而，由于两类参数的估算均存在诸多难点，当前学界对自然种群中Nb/Na比值的认知仍较为匮乏。
亲属频率（sibship frequency, SF）方法可实现可靠的Nb估算：该方法通过遗传标记数据重构同胞家系与亲权关系，所得种群统计推断结果可与野外实地调查数据相互比对验证。此外，标记-重捕（capture-mark-recapture, CMR）稳健设计方法则非常适用于季节性繁殖物种的Na估算。
本研究选取3种池栖繁殖两栖类（黄条背蟾蜍Epidalea calamita、欧洲雨蛙Hyla molleri、佩氏侧褶蛙Pelophylax perezi；每个物种的单批次蝌蚪样本量为73~96只，均在15~17个微卫星位点完成基因分型）的蝌蚪基因型，以及对应物种的候选亲本基因型（每个物种成年个体样本量为94~300只），采用SF方法估算Nb。为评估Nb估算结果的可靠性，本研究将同胞家系与亲权关系的推断结果与野外实地调查信息进行比对，并通过重复子采样分析检验结果的收敛性。最后，本研究借助为期6年的监测项目所获CMR数据，估算了3个物种的年度成年种群普查量Na，并据此计算Nb/Na比值。
研究结果显示，黄条背蟾蜍与佩氏侧褶蛙的Nb/Na比值估算结果可靠（分别为0.18~0.28与0.5）；但对于欧洲雨蛙，未能成功估算Na，且现有遗传信息不足以支撑可靠的Nb估算。
充分结合SF与CMR方法优势的综合种群统计研究，可实现季节性繁殖物种Nb/Na比值的精准估算。尤为重要的是，SF方法所得结果可直接开展可靠性评估，这为进化生物学与保护生物学研究提供了一类具备广泛应用潜力的稳健种群统计推断途径。