Refugial isolation and divergence in the Narrowheaded Gartersnake species complex (Thamnophis rufipunctatus) as revealed by multilocus DNA sequence data

Glacial–interglacial cycles of the Pleistocene are hypothesized as one of the foremost contributors to biological diversification. This is especially true for cold‐adapted montane species, where range shifts have had a pronounced effect on population‐level divergence. Gartersnakes of the Thamnophis rufipunctatus species complex are restricted to cold headwater streams in the highlands of the Sierra Madre Occidental and southwestern USA. We used coalescent and multilocus phylogenetic approaches to test whether genetic diversification of this montane‐restricted species complex is consistent with two prevailing models of range fluctuation for species affected by Pleistocene climate changes. Our concatenated nuDNA and multilocus species analyses recovered evidence for the persistence of multiple lineages that are restricted geographically, despite a mtDNA signature consistent with either more recent connectivity (and introgression) or recent expansion (and incomplete lineage sorting). Divergence times estimated using a relaxed molecular clock and fossil calibrations fall within the Late Pleistocene, and zero gene flow scenarios among current geographically isolated lineages could not be rejected. These results suggest that increased climate shifts in the Late Pleistocene have driven diversification and current range retraction patterns and that the differences between markers reflect the stochasticity of gene lineages (i.e. ancestral polymorphism) rather than gene flow and introgression. These results have important implications for the conservation of T. rufipunctatus (sensu novo), which is restricted to two drainage systems in the southwestern US and has undergone a recent and dramatic decline.     

Holocene altitudinal shifts in vegetation belts and environmental changes in the Sierra Madre Occidental, Northwestern Mexico, based on modern and fossil pollen data

A modern pollen rain study was performed in a 300 km-long altitudinal transect (~ 28° N latitude) from 300 to 2300 m elevation. The higher elevation modern communities: epithermal oak–pines, pine–oak forest, pine forest, and mixed conifer forest were easy to distinguish from their pollen content. In contrast, lower elevation subtropical communities: thornscrub and tropical deciduous forest were difficult to separate, because they share many pollen taxa. Nevertheless we identify high frequencies of Bursera laxiflora as an important component of the tropical deciduous forest.Additionally, fossil pollen was analyzed at three sites located between 1700 and 1950 m altitude at ~ 28° latitude north in the Sierra Madre Occidental of northwestern Mexico. The sites were in pine–oak (Pinus–Quercus), pine, and mixed-conifer forests respectively. Shifts in the altitudinal distribution of vegetation belts were recorded for the last 12,849 cal yr BP, and climate changes were inferred. The lowest site (pine–oak forest) was surrounded by pine forest between 12,849 and 11,900 cal yr BP, suggesting a cold and relatively dry Younger Dryas period. The early Holocene was also cold but wetter, with mixed conifer forest with Abies (fir) growing at the same site, at 1700 m elevation, 300 m lower than today. After 9200 cal yr BP, a change to warmer/drier conditions caused fir migration to higher elevations and the expansion of Quercus at 1700 m. At 5600 cal yr BP Abies was growing above 1800 m and Picea (spruce) that is absent today, was recorded at 1950 m elevation. Fir and spruce disappeared from the 1950 m site and reached their present distribution (scattered, above 2000 m) after 1000 cal yr BP; we infer an episodic Holocene migration rate to higher elevations for Abies of 23.8 m/1000 cal yr and for Picea of 39.2 m/1000 cal yr. The late Holocene reflects frequent climate oscillations, with variations in the representation of forest trees. A tendency towards an openness of the forest is recorded for the last 2000 yrs, possibly reflecting human activities along with short-term climate change.     

Spatial patterns of Mexican pine-oak forests under different recent fire regimes

Patterns of spatial arrangement, tree density, and species composition were compared in three unharvested pine-oak forests under different recent fire regimes: (1) an uninterrupted frequent fire regime, (2) fire exclusion, and (3) fire exclusion followed by the return of fire. Regeneration was dense and highly aggregated at all sites but the frequent-fire overstory was random to uniform in spatial distribution and relatively open while the fire-excluded sites had clumped overstory trees with a high density of smaller trees. Dominance by sprouting species was greatest at the fire-excluded sites. Mortality was spatially aggregated at all sites, consistent both with thinning by fire and density-dependent mortality, but competitive self-thinning appeared insufficient to counteract the increased tree density without fire. The return of fire after 29 years of exclusion reduced tree density but left overstory trees aggregated and led to vigorous oak and alder sprouting. Frequent fire disturbance is considered essential to maintain open pine forests; fire exclusion with or without subsequent fire appears to lead to denser forests dominated by smaller trees of sprouting species.     

The amphibians and reptiles of Luzon Island,Philippines, VIII: the herpetofauna of Cagayan and Isabela Provinces,northern Sierra Madre Mountain Range

We provide the first report on the herpetological biodiversity (amphibians and reptiles) of the northern Sierra Madre Mountain Range (Cagayan and Isabela provinces), northeast Luzon Island, Philippines. New data from extensive previously unpublished surveys in the Municipalities of Gonzaga, Gattaran, Lasam, Santa Ana, and Baggao (Cagayan Province), as well as fieldwork in the Municipalities of Cabagan, San Mariano, and Palanan (Isabela Province), combined with all available historical museum records, suggest this region is quite diverse. Our new data indicate that at least 101 species are present (29 amphibians, 30 lizards, 35 snakes, two freshwater turtles, three marine turtles, and two crocodilians) and now represented with well-documented records and/or voucher specimens, confirmed in institutional biodiversity repositories. A high percentage of Philippine endemic species constitute the local fauna (approximately 70%). The results of this and other recent studies signify that the herpetological diversity of the northern Philippines is far more diverse than previously imagined. Thirty-eight percent of our recorded species are associated with unresolved taxonomic issues (suspected new species or species complexes in need of taxonomic partitioning). This suggests that despite past and present efforts to comprehensively characterize the fauna, the herpetological biodiversity of the northern Philippines is still substantially underestimated and warranting of further study.     

栗头鹟莺繁殖生态的初步观察

鹟莺属(Seicercus)鸟类的繁殖资料十分缺乏。2015年4~8月,采用录像全程监控的方法,在贵州宽阔水国家级自然保护区,对4巢栗头鹟莺(S.castaniceps)的繁殖过程进行了完整观察。栗头鹟莺的繁殖期主要集中在5~7月,巢址选择专一性较强,均筑巢于公路边的土坎内壁,距路(1.3±1.2)m,巢为球状侧开口,巢材主要为新鲜苔藓及细草根,巢高(2.2±0.6)m,巢宽(10.9±1.5)cm,杯宽(3.3±0.5)cm,巢深(9.5±1.9)cm,杯深(5.5±1.0)cm。窝卵数(4.5±0.6)枚(4~5枚),卵重(0.92±0.04)g,卵长(14.30±0.30)mm,卵宽(11.22±0.23)mm,卵体积(0.92±0.05)mm3(n=18)。亲鸟在产满窝卵后开始孵卵,孵卵期12~13 d,在孵卵中期(第5~9天)亲鸟的孵卵时间开始增加,翻卵次数增多,在孵卵后期(第10~13天)亲鸟的孵卵时间和翻卵次数基本保持不变。育雏期13~14 d。雌、雄共同育雏,雏鸟在3日龄时,体重和跗跖开始显著增长,在7日龄时,增长速度变缓。孵化率为88.9%(16/18),营巢成效为100%,出飞成效为3.3只/巢。     

黄嘴鹮鹳混群笼养繁殖和育雏行为观察

从2006年到2008年间对黄嘴鹮鹳的饲养环境进行人工调节,采用焦点动物法和扫描取样法对黄嘴鹮鹳的繁殖行为、雏鸟的生长发育进行观察.结果表明,人工措施可使黄嘴鹮鹳在北京地区全年繁殖;亲鸟在育雏期共同养育雏鸟;雏鸟属晚成鸟,但与鹮类相比,在生长发育上有特异性,更接近于鹳.