喀喇昆仑,昆仑山地区植物元素含量的区域分异和数量分析

对喀喇昆仑昆仑山地区８７种植物２１个元素含量及区域分异的研究表明,Ｃａ、Ｃｒ、Ｃｄ、Ｆｅ、Ｖ含量比高等植物含量偏高,Ｐ,Ｐ的含量偏低,同种植物在不同地点元素含量有差异,盐柴荒漠植物中Ｎａ,Ｋ,Ｍｇ,Ｐ含量较高;高山草甸、冰缘植被植物Ｂ,Ｃ,Ｆ,Ｖ,Ｔ含量较高,各植被类型植物元素含量Ｎａ／Ｋ差异最大,Ｃａ／Ｍｇ较小,Ｆｅ／Ａｌ差异最小,其变异系数分别为１５３．５、２０．５和１５．９％。     

小兴安岭阔叶红松林不同演替系列森林细根生物量的研究

以小兴安岭地区阔叶红松林旱生演替系列的蒙古栎次生林和蒙古栎红松林、中生演替系列的枫桦次生林和枫桦红松林、湿生演替系列的白桦次生林和云冷杉红松林这6种林型为研究对象,采用土钻取样法对不同演替系列细根生物量的空间变化、垂直分布规律及其影响因子进行系统地研究。结果表明：（1）3种演替系列总细根生物量存在显著差异（P<0.05）。中生演替系列生物量最高,平均达8.56 t·hm^-2,其次是旱生演替系列8.18 t·hm^-2,湿生演替系列生物量最低,为5.79 t·hm^-2;（2）对于不同演替系列细根生物量垂直变化,在阔叶红松林的正向演替过程中,森林细根生物量逐渐增加,且随着土层的增加而降低,拟合效果均达显著水平（P<0.05）,中根和粗根的垂直分布差异较大;（3）在小兴安岭地区,6块林地不同径级细根生物量与土壤有机C和全N、土壤容重、土壤含水率呈显著负相关（P>0.05）,而土壤pH值与细根生物量呈显著正相关性（P>0.05）。     

高黎贡山土壤微生物的数量和多样性

本文从分解者亚系统水平,研究了高黎贡山海拔1000～3100m的不同植被下土壤中微生物的数量和多样性,对不同海拔高度、不同植被下的12份土壤样品,进行了微生物数量、真菌多样性及养分含量的测定,结果得出：细菌、真菌、放线菌数量和真菌多样性随海拔不同而变化,最高值出现在海拔2000m左右,其植被下土壤微生物的数量和多样性最高,随海拔升高或降低均呈下降趋势,在山底降到较低水平。土壤微生物随海拔高度的变化与生态因子呈现不同程度的相关性,其中,微生物的数量和多样性与气温、有机质之间的相关性最大,除细菌数量与气温、真菌数量与有机质外,都达到了显著的水平;与有效氮、土壤含水量之间的相关性次之;而与速效磷和速效钾的相关性较差。说明影响高黎贡山土壤微生物数量和多样性垂直分布的主要生态因子是气温、土壤有机质和有效氮含量、土壤含水量,现有土壤磷和钾含量的变化对土壤微生物数量和多样性的影响相对较小。     

祁连山特有濒危植物穴丝荠分布预测及其重要影响因子分析

穴丝荠是祁连山特有濒危植物,预测潜在适生区可为穴丝荠的保护与研究提供重要参考。基于地理分布记录和环境因子变量数据,采用MaxEnt和ArcGIS模型,利用41个有效分布点和28个环境因子,模拟了穴丝荠当代、未来(2050s、2070s) RCP2.6、RCP4.5和RCP8.5气候情景下在祁连山的适生分布区,并筛选影响其分布的主导因子。结果显示：(1)训练数据集的AUC值均值达到0.948,随机误差均值达0.043,表明MaxEnt模型模拟预测精度较高。(2)影响穴丝荠分布的主导因子有海拔、平均气温日较差、等温性、最潮湿度月份的降水量和土壤有机质,这些环境因子占总贡献率的87.4%。(3)海拔在3 000~4 000 m处,平均温度日较差在10 ℃~12 ℃,等温性为32~35,最潮湿月份的降水在140~160 mm,土壤有机质含量在1.2%~1.5% 时较适宜穴丝荠的生长,推测穴丝荠适合生长于热量低、日温差大且年温差小、寒冷半湿润型的高原气候。(4)在当代气候条件下,穴丝荠的潜在地理分布主要位于祁连山东部和南部地区,随着气候变化和时间推移,穴丝荠潜在适生区有缩小趋势,祁连山南部地区高度适生区向北部收缩,大部分集中于祁连山保护区内。(5)未来应首先考虑重点保护祁连山保护区内的种群,并可将祁连山保护区南部一带作为保护区域进行就地保护。     

大仓鼠DNA指纹谱探针的筛选

采用一种简便提取高质量DNA 的方法, 从大仓鼠肝脏组织中提取其总DNA , 分别以人工合成的微卫星核心序列(GTG)₅和(CA)₈做单一引物, 进行特异引物PCR 反应。电泳检测后回收15 条特异性片段。与被标记过的大仓鼠基因组DNA 反向杂交结果表明, 15 个片段中(GTG)_5-8 、(CA)_8-1b和(CA_{) 8-5b}产生了较强的阳性信号。我们依据3 个片段的测序结果设计适合DIG标记的探针, 该探针得到的大仓鼠不同地理种群个体的指纹图谱有较高的个体特异性和种群多态性, 而且与传统的来源于其它生物重复序列的探针如33.6 和33.15 形成的指纹图谱相比得到的变异适中, 便于统计。     

一种复方避孕药物对围栏内大仓鼠种群繁殖力的影响

本文报道了由左炔诺孕酮和炔雌醚配伍制成的复方避孕药物(代号: EP －1) 对围栏内大仓鼠种群繁殖力的影响。实验分为4 个组: 对照组、0.001 %毒饵组、0.003 %毒饵组和0.003 %毒饵预处理组, 并各设有一组重复。于2001 年6 月, 在每组围栏内各放入5 雄5 雌成年大仓鼠, 检验投放EP－1 毒饵后对大仓鼠繁殖力的影响。至9 月份, 2 个对照组新出生鼠数量均为12 只, 平均每雌繁殖力为214 ; 而所有6 个EP －1 处理组新出生鼠数量均为4 只或以下, 平均每雌繁殖力在014～018 之间。结果表明, 处理组大仓鼠的繁殖力明显受到了不育剂EP－1的抑制。在半自然状况下, 投放足量的EP－1 毒饵可以有效降低大仓鼠种群的繁殖力和数量。     

DNA metabarcoding reveals that African leopard diet varies between habitats

Understanding carnivores’ diet is key to understanding their adaptability in a rapidly changing world. However, studying diet of large carnivores is difficult due to their elusive nature. In this study, we performed DNA metabarcoding analyses of 82 putative leopard scats collected from two distinct, but connected, habitat types (rainforest and grassland) in the Udzungwa Mountains, Tanzania. Two mitochondrial markers were used to identify predator and prey. Metabarcoding confirmed that 60 of the collected scats (73%) originated from leopards, and nineteen mammalian prey DNA sequences were identified to species. Using prey size correction factors for leopards, and covariates on habitat type and prey ecology, we investigated whether differences in leopard dietary composition were detectable between habitats. We found that leopards in grassland consumed a larger mean prey size compared with leopards in rainforest. Small prey (<19 kg) constituted >70% of the biomass consumed by leopards in rainforest, while large prey (≥80 kg) were only eaten in grassland. Arboreal species constituted 50% of the biomass consumed by rainforest leopards. Our results highlight the importance of arboreal species in their diet. From a management perspective, we suggest continued protection of all prey species in the protected areas to prevent human–wildlife conflicts.     

Conceptual Ecological Model of the Chiquibul/Maya Mountain Massif,Belize

The Chiquibul/Maya Mountain Massif (CM3) is an approximately 1.25 million-acre area in southwestern Belize and is among the most intact tropical forests north of the Amazon. The CM3 has a variety of habitats that contribute to its valuable environmental services and high aesthetic value, but despite its protected area status, the CM3 is under increasing pressure from extraction of natural and cultural resources as a result of transboundary incursions on the western border and increased land-use changes from industrial activities that include agriculture, hydropower development, logging, and mining. Conceptual ecological models (CEM) are effective planning tools for organizing existing information about natural systems for determining gaps in knowledge and research priorities, and for developing objectives and measures of success for management and monitoring programs. The CEM of the CM3 describe ecological relationships among major stressors and attributes of the system and presents performance measures to quantify potential change to attributes. Attributes were derived from defining characteristics of the massif and chosen as valuable ecological and cultural components of the massif. Ecological linkages between stressors and attributes highlight priorities for conservation, management, and research that will ensure continued protection of the CM3.     

Elk survival and mortality causes in the Blue Mountains of Washington

We studied survival of elk (Cervus elaphus) ≥1 yr old and quantified mortality sources in the Blue Mountains of Washington, 2003–2006, following a period of extensive poaching. The population was managed under a spike-only general hunting season, with limited permits for larger males and for females. We radiomarked 190 elk (82 males and 39 females >1 yr old and 65 males 11 months old), most with rumen transmitters and neck radiocollars; 60 elk only received rumen transmitters. We estimated annual survival using known fate models and explored survival differences among sex and age classes and in 2 potentially different vulnerability zones for males. We found little support for differences in survival between younger (2–3-yr old) and older (≥4-yr old) branch-antlered males or zone differences for yearling males. A model with zone differences for branch-antlered males was the second ranked model and accounted for 14% of the available model weight. From the best-supported models, we estimated annual survival for yearling males at 0.41 (95% CI: 0.29–0.53). We estimated pooled adult female survival at 0.80 (95% CI: 0.64–0.93); when an age-class effect was included, point estimates were higher for prime-aged females (2–11 yr: S = 0.81 [0.70–0.88]) than for older females (≥12 yr: S = 0.72 [0.56–0.83]), but confidence intervals broadly overlapped. Only 1 of 7 models with a female age effect on survival was among the competitive models. For branch-antlered males, survival ranged 0.80–0.85, depending on whether zone variation was modeled. We recorded 78 deaths of radiomarked elk. Human-caused deaths (n = 55) predominated among causes and most were of yearling males killed during state-sanctioned hunts (n = 28). Most subadult male deaths were from tribal hunting (n = 5), and most mature males died from natural causes (n = 6) and tribal hunting (n = 5). We detected few illegal kills (n = 4). Our results suggest that increased enforcement effectively reduced poaching, that unreported tribal harvest was not a trivial source of mortality, and that spike-only general seasons were effective in recruiting branch-antlered males. © 2011 The Wildlife Society.