Evaluation of non-invasive genetic sampling methods for estimating tiger population size

There is often a conservation need to estimate population abundances of elusive, low-density, wide-ranging carnivore species. Because of logistical constraints, investigators often employ non-invasive ‘captures’ that may involve ‘genetic’ or ‘photographic’ sampling in such cases. Established capture–recapture (CR) methods offer a powerful analytical tool for such data. In this paper, we developed a rigorous combination of captive, laboratory and field-based protocols for identifying individual tigers (Panthera tigris) from fecal DNA. We explored trade-offs between numbers of microsatellite loci used for reliable individual identifications and the need for higher capture rates for robust analyses. Our field surveys of scats were also specifically designed for CR analyses, enabling us to test for population closure, estimate capture probabilities and tiger abundance. Consequently, we could compare genetic capture estimates to results of a ‘photographic capture’ study of tigers at the same site. The estimates using the heterogeneity model (M_h-Jackknife) for fecal DNA survey were [M_t+1 = 26; and ()=66 (12.98)] in close agreement with those from the photographic survey [(M_t+1 = 29; and () = 66 (13.8)]. Our results revealed that designing field surveys of scats explicitly for CR data analyses generate reliable estimates of capture probability and abundance for elusive, low density species such as tigers. The study also highlights the importance of rigorous field survey and laboratory protocols for reliable abundance estimation in contexts where other approaches such as camera-trapping or physical tagging of animals may not be practical options.     

Modeling individual tree height growth of Norway spruce and Scots pine from national forest inventory data in Norway

We developed individual tree height growth models for Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) in Norway based on national forest inventory data. Potential height growth is based on existing dominant height growth models and reduced due to competition by functions developed in this study. Three spatially explicit and two spatially non-explicit competition indices were tested. Distance effects and diameter ratio effects were estimated from the data simultaneously with parameters of the potential modifier functions. Large height measurement errors in the national forest inventory data caused large residual variation of the models. However, the effects of competition on height growth were significant and plausible. The potential modifier functions show that height growth of dominant trees is largely unaffected by competition. Only at higher levels of competition, height growth is reduced as a consequence of competition. However, Scots pine also reduced height growth at very low levels of competition. Distance effects in the spatially explicit competition indices indicated that the closest neighbors are most important for height growth. However, for Scots pine also competitors at larger distance affected height growth. The five competition indices tested in this study explained similar proportions of the variation in relative height growth. Given that unbiased predictions can only be expected for the same plot size, we recommend a spatially explicit index, which describes the distance function with a negative exponential, for use in growth simulators.     

犬标准化行为测验量表的研究进展

在犬的驯养过程中,人类根据不同的使用目的对其施加了较高强度的人工选择,培育出了形态、行为和性情各异的众多品种及个体。犬个体行为差异为研究动物的个性、行为进化以及行为应用等领域提供了有价值的模型。总结和分析了近几十年来心理学家和行为学家所使用的犬行为测验量表的差异,为编制标准化犬行为测验量表提供理论依据。     

Predicting individual breeding values and making forward selections from open-pollinated progeny test trials for seed orchard establishment of interior Lodgepole Pine (<Emphasis Type="Italic">Pinus contorta</Emphasis> ssp. <Emphasis Type="Italic">latifolia</Emphasis>) in British Columbia

Ten-year height data from three open-pollinated lodgepole pine progeny test trials were analysed in order to select individuals for seed orchard establishment in the low and high elevation seed-planning units (TOLO and TOHI) of the new Thompson Okanagan seed planning-zone in interior British Columbia, Canada. The total test population had about 35,000 individuals from 362 families of 9 provenances and was divided into two portions, each serving as the base population for its appropriate seed-planning unit. For each population, various genetic parameters were estimated and individual breeding values were predicted. Combined-site estimates of individual, family, and within-family heritability ranged from 0.23 to 0.38, 0.77 to 0.84, and 0.17 to 0.29, respectively. Estimated coefficients of type-b genetic correlation were greater than 0.81, indicating little G × E interaction in this region. Provenance effects were large. Larch Hills and Inonoaklin River were the two superior provenances with an expected gain of 13% and 10% in stem volume at rotation age of 60 years in TOLO. Individual breeding values was not uniformly distributed among provenances and the top 100 individuals originated from 20 families in TOLO and 32 families in TOHI. Co-ancestry among these individuals should not be a serious concern in seed orchard establishment as the predicted genetic loss due to excessive inbreeding is only 1.06% in TOLO and 0.6% in TOHI. The status numbers of the two prospective seed orchards are 32 and 44, respectively, and both are well above the required minimum of 10 in British Columbia. Using unrelated clones for seed orchard establishment may result in reduced optimum genetic gain and thus is not a favourable option.     

Biomass and carbon sequestration of ponderosa pine plantations and native cypress forests in northwest Patagonia

Fast growth tree plantations and secondary forests are considered highly efficient carbon sinks. In northwest Patagonia, more than 2 million ha of rangelands are suitable for forestry, and tree plantation or native forest restoration could largely contribute to climate change mitigation. The commonest baseline is the heavily grazed gramineous steppe of Festuca pallescens (St. Yves) Parodi. To assess the carbon sequestration potential of ponderosa pine (Pinus ponderosa (Dougl.) Laws) plantations and native cypress (Austrocedrus chilensis (Don) Flor. et Boutl.), individual above and below ground biomass models were developed, and scaled to stand level in forests between 600 and 1500 annual rainfall. To calculate the carbon sequestration baseline, the pasture biomass was simulated. Also, soil carbon at two depths was assessed in paired pine-cypress-pasture sample plots, the same as the litter carbon content of both forest types. Individual stem, foliage, branch and root log linear equations adjusted for pine and cypress trees presented similar slopes (P>0.05), although some differed in the elevations. Biomass carbon was 52.3 Mg ha⁻¹ (S.D.=30.6) for pine stands and 73.2 Mg ha⁻¹ (S.D.=95.4) for cypress forests, given stand volumes of 148.1 and 168.4 m³ ha⁻¹, respectively. Soil carbon (litter included) was 86.3 Mg ha⁻¹ (S.D.=46.5) for pine stands and 116.5 Mg ha⁻¹ (S.D.=38.5) for cypress. Root/shoot ratio was 19.5 and 11.4%, respectively. The low r/s value for cypress may account for differences in nutrient cycling and water uptake potential. At stand level, differences in foliage, taproot and soil carbon compartments were highly significative (P<0.01) between both forest types. In pine stands, both biomass and soil carbon were highly explained by the rainfall gradient (r²=0.94). Nevertheless, such a relationship was not found for cypress, possibly due to stand and soil disturbances in sample plots. The carbon baseline estimated in pasture biomass, including litter, was 2.6 Mg ha⁻¹ (S.D.=0.8). Since no differences in soil carbon were found between pasture and both forest types, additionality should be accounted only by biomass. However, the replacement of pasture by pine plantations may decrease the soil carbon storage, at least during the first years. On the other hand, the soil may be a more relevant compartment of sequestered carbon in cypress forests, and if pine plantation replaces cypress forests, soil carbon losses could cause a negative balance.     

论林改后个体林果业发展的机遇、问题与对策——都昌县个体发展林果业案例分析

通过对都昌县个体发展林果业的案例分析,探讨林改后个体林果业发展的经营模式、成就,存在的问题及应采取的相应对策。     

The effect of competition on individual tree basal area growth in mature stands of Pinus cooperi Blanco in Durango (Mexico)

In this paper, we evaluated how well-selected distance-dependent and distance-independent competition indices explain individual tree basal area growth of trees, growing in mature and even-aged stands of Pinus cooperi Blanco. A total of 18 competition measures were analyzed of which six do not need tree location (distance-independent) and 12 that utilize tree location (distance-dependent). The competition situation of a stand and/or an individual tree was studied using 11 different competitor selection methods. The mean square error reduction relative to no-competition was used to judge the performance of each competition index. It was found that the best distance-independent competition indices performed as well as the best distance-dependent competition indices. It was concluded that the BALMOD-index would be a good competition index to be incorporated into further individual tree basal area growth models for the study area.

鸡屎藤地上部分化学成分的初步研究

通过系统预试和单项预试，初步确定鸡尿藤地上部分含有酚类，有机酸，生物碱，氨基酸、多肽（或蛋白质）、糖、多糖（或甙类）、黄酮及其甙类、甾醇（或三萜）和挥发油等成分。     

Snf907真菌代谢物对大豆胞囊线虫卵及二龄幼虫的影响

研究Snf907真菌代谢物原液及不同稀释液对大豆胞囊线虫卵孵化及二龄幼虫活性的影响.结果表明,在原液、5×、10×、20×、50×稀释液浓度下,对胞囊孵化的相对抑制率分别是88.34%、82.33%、74.32%、57.01%和38.62%,均与无菌水对照差异显著;对分散卵粒孵化的相对抑制率分别是98.86%、92.66%、84.19%、72.32%和65.54%,除了50×稀释液浓度外,其他浓度均与无菌水对照差异显著;对二龄幼虫的校正死亡率分别是96.33%、83.18%、63.15%、47.04%和33.99%,均与无菌水对照差异显著.     

Higher food abundance reduces the catchability of cod (Gadus morhua) to longlines on the Faroe Plateau

The cod fishery at the Faroes has been managed since 1996 by an effort management system where it is assumed that there is a direct relationship between fishing mortality and fishing effort. We show that this relationship is weak. Due to a factor five variation in the primary production on the Faroe Plateau, the annual growth rate of cod may vary by a factor of five. Commercial catch-per-unit-effort data in combination with stock assessment estimates showed that there was a negative correlation between the annual growth rate of cod and their catchability with longlines, as well as with the total fishing mortality of cod on the Faroe Plateau. Furthermore, mark-recapture experiments showed that longline-caught cod in comparison with trawl-caught cod had a lower condition factor, a lower stomach content of natural prey, and a higher content of longline baits. During the feeding season in September–December, longline-caught cod exhibited a larger displacement distance than trawl-caught cod. These results were largely confirmed by storage tag data. Consequently, during low-productive periods, (i) the longline-dominated cod fishery at the Faroes exerted fishing mortalities that by far exceeded safe biological limits, and (ii) longline catch-per-unit-effort series might overestimate stock size considerably.