Living at the Edge: Local versus Positional Factors in the Long‐Term Population Dynamics of an Endangered Orchid

Abstract: Populations at the margin of geographic ranges of distribution have been considered more vulnerable than central ones, but recent reviews have caste doubt on this generalization. We examined the reproductive and demographic performance of a rare Euroasiatic orchid (Cypripedium calceolus) at its southwesterly range limit and compared our findings with those of previous studies of nine central populations at the center of the orchid's range. We sought to test the central‐marginal model and to evaluate factors involved in long‐term performance of forest Eurosiberian species with peripheral populations in southern European mountains. We characterized (structure, temporal fluctuations, herbivory, reproductive success, and recruitment at different habitats) four Pyrenean populations of C. calceolus of different sizes (5–3500 ramets) and monitored three of them for up to 13 years. Two quantitative stochastic models (count data and matrix models) were used to assess population trends and viability and the effect of herbivory. Contrary to expectations, and despite the negative effect of sporadic events of herbivory, the peripheral populations we studied (except the smallest one) performed similarly or better than populations occurring in central part of the species’ range in terms of reproductive success and population growth rates. Landscape changes over the last 50 years suggest that natural reforestation could be involved in the success of this plant at its southern limit. Forest expansion in the mountain regions of southern Europe may provide new opportunities for plants with geographic distributions centered mainly at higher latitudes and give some hope for their recovery in future scenarios dominated by biodiversity loss.     

Interactive Effects of Harvest and Deer Herbivory on the Population Dynamics of American Ginseng

Abstract:  Few demographic models for any species consider the role of multiple, interacting ecological threats. Many forest herbs are heavily browsed by white-tailed deer ( Odocoileus virginianus ) and a number of these are also harvested for the medicinal, floral, or horticultural trades. Previous studies of the viability of American ginseng ( Panax quinquefolius ) have separately examined the effects of harvesting and deer herbivory. We followed individually marked ginseng plants in 6 populations for 8 years and documented deer browse levels, conducted helicopter surveys to estimate the deer herd size, and documented 2 ginseng harvests. We used this long-term data set to develop a stochastic demographic model that quantified the separate and interactive role of these threats to ginseng viability. Although harvesting and deer herbivory negatively affected ginseng population growth, their effects were not additive. Deer herbivory negatively affected population growth in the absence but not in the presence of harvesting. Life table response experiments revealed that in the presence of harvesting, deer herbivory had some positive effects on vital rates because browsed plants were less apparent to harvesters. Ginseng populations that were harvested responsibly (i.e., planting seeds from harvested individuals) had higher growth rates than those that were harvested irresponsibly. We concluded that both deer populations and harvesting must be managed to ensure sustainable populations of American ginseng. Our findings underscore the importance of long-term monitoring to assess threats to viability and the need for a broad ecological understanding of the complexity of ecosystem management.     

A multiscale hierarchical Markov transition matrix model for generating and analyzing thematic raster maps

A model is described for generating hierarchically scaled spatial pattern as represented in a thematic raster map. The model involves a series of Markov transition matrices, one for each level in the scaling hierarchy. In full generality, the model allows the transition matrices to be different at each level, potentially making available a large number of parameters for landscape characterization. The model is self-similar when the transition matrices are all equal. A method is presented for fitting the model to data that take the form of a single-resolution thematic raster map. Explicit analytic solutions are obtained for the fitted parameters. The fitting method is based on a relationship between the hierarchical transitions in the model and spatial transitions at varying distance scales in the data map, a categorical analogy of the geostatistical variogram.     

Land Development in and around Protected Areas at the Wilderness Frontier

Protected areas’ chief conservation objectives are to include species within their boundaries and protect them from negative external pressures. Many protected areas are not achieving these goals, perhaps in part due to land development inside and outside protected areas. We conducted spatial analyses to evaluate the ability of Canadian protected areas to mitigate the effects of nearby land development. We investigated correlations of national patterns of land development in and around protected areas and then examined national patterns of roads, urban area, and croplands in protected areas. We calculated the amount of developed land in protected areas and within 25–100 km of protected‐area borders, the density of roads, and extent of urban and cropland area in protected areas. We constructed logistic‐regression models to test whether development in a protected area was associated with landscape and protected‐area characteristics. Land development was far less extensive inside than outside protected areas. However, several protected areas, particularly small southern areas near small urban centers had substantial development inside their boundaries, and nearly half of protected areas had roads. The cumulative extent of development within 50 km of protected areas was the best predictor of the probability of land development in protected areas. Canadian First Nations, industries, government, and nongovernmental organizations are currently planning an unprecedented number of new protected areas. Careful management of areas beyond protected‐area boundaries may prove critical to meeting their long‐term conservation objectives. Desarrollo de Tierras Dentro y Alrededor de Áreas Protegidas en la Frontera Silvestre     

Application of decision tools to ethical analysis in biodiversity conservation

Achieving ethically responsible decisions is crucial for the success of biodiversity conservation projects. We adapted the ethical matrix, decision tree, and Bateson's cube to assist in the ethical analysis of complex conservation scenarios by structuring these tools so that they can implement the different value dimensions (environmental, social, and animal welfare) involved in conservation ethics. We then applied them to a case study relative to the decision-making process regarding whether or not to continue collecting biomaterial on the oldest of the two remaining northern white rhinoceroses (Ceratotherium simum cottoni), a functionally extinct subspecies of the white rhinoceros. We used the ethical matrix to gather ethical pros and cons and as a starting point for a participatory approach to ethical decision-making. We used decision trees to compare the different options at stake on the basis of a set of ethical desiderata. We used Bateson's cube to establish a threshold of ethical acceptability and model the results of a simple survey. The application of these tools proved to be pivotal in structuring the decision-making process and in helping reach a shared, reasoned, and transparent decision on the best option from an ethical point of view among those available.     

Effects of Forest Fragmentation on Seed Dispersal and Seedling Establishment in Ornithochorous Trees

Abstract: Habitat fragmentation increases seed dispersal limitation across the landscape and may also affect subsequent demographic stages such as seedling establishment. Thus, the development of adequate plans for forest restoration requires an understanding of mechanisms by which fragmentation hampers seed delivery to deforested areas and knowledge of how fragmentation affects the relationship between seed‐deposition patterns and seedling establishment. We evaluated the dispersal and recruitment of two bird‐dispersed, fleshy‐fruited tree species (Crataegus monogyna and Ilex aquifolium) in fragmented secondary forests of northern Spain. Forest fragmentation reduced the probability of seed deposition for both trees because of decreased availability of woody perches and fruit‐rich neighborhoods for seed dispersers, rather than because of reductions in tree cover by itself. The effects of fragmentation went beyond effects on the dispersal stage in Crataegus because seedling establishment was proportional to the quantities of bird‐dispersed seeds arriving at microsites. In contrast, postdispersal mortality in Ilex was so high that it obscured the seed‐to‐seedling transition. These results suggest that the effects of fragmentation are not necessarily consistent across stages of recruitment across species. Habitat management seeking to overcome barriers to forest recovery must include the preservation, and even the planting, of fleshy‐fruited trees in the unforested matrix as a measure to encourage frugivorous birds to enter into open and degraded areas. An integrative management strategy should also explicitly consider seed‐survival expectancies at microhabitats to preserve plant‐population dynamics and community structure in fragmented landscapes.     

基于水化学分析的煤矿矿井突水水源判别

矿井突水是煤矿生产过程中的主要自然灾害,准确判定矿井突水水源是解决突水问题的重要条件。基于模糊综合评判和矩阵方程分析数学原理,分别建立了矿井突水的模糊综合评判和矩阵方程分析模型;在水化学分析的基础上,建立了水样6项指标评判标准,利用两种方法分别对某煤矿3个不同突水巷道水样进行了水源判别,并与实际突水水源相比较。结果表明,模糊综合评判和矩阵方程分析均能有效判别矿井突水水源,但各有其优越性及局限性,选择何种判别方法应视矿井突水水化学资料状况而定。     

乌江水库水体中有机胶粒的三维荧光特征研究

超滤与三维荧光光谱的结合可以表征不同类型荧光物质相对分子量的分布规律,揭示它们的来源以及组分差异.本项研究用截留相对分子量为1 000和10 000的再生纤维素超滤膜,对乌江水库不同深度水体中的溶解有机质进行了分离,利用三维荧光光谱表征了3种不同相对分子量组分中发荧光有机质的光谱特征.结果表明:荧光物质主要存在于真溶液(＜1 000)中.水体在丰水期和枯水期的荧光峰存在差异.丰水期主要存在4种类型的荧光峰:类富里酸荧光A峰和C峰,类蛋白荧光峰B峰和D峰.枯水期则只表现出3种类型的荧光峰,类富里酸荧光峰C不明显,原因可能是此时水库处于蓄水状态,内部生物活动作用显著,产生的类蛋白荧光物质强度较大从而掩盖峰C的强度.然而72 m以下由于厌氧还原条件的出现,沉积物向水体释放了溶解有机质组分,原本强度被掩盖的荧光峰C明显出现在1 000～10 000组分中.     

Monthly survey of N-nitrosamine yield in a conventional water treatment plant in North China

A sampling campaign was conducted monthly to investigate the occurrence of N-nitrosamines at a conventional water treatment plant in one city in North China. The yield of N-nitrosamines in the treated water indicated precursors changed greatly after the source water switching. Average concentrations of N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR), and N-nitrosopyrrolidine (NPYR) in the finished water were 6.9, 3.3, and 3.1 ng/L, respectively, from June to October when the Luan River water was used as source water, while those of NDMA, N-nitrosomethylethylamine (NMEA), and NPYR in the finished water were 10.1, 4.9, and 4.7 ng/L, respectively, from November to next April when the Yellow River was used. NDMA concentration in the finished water was frequently over the 10 ng/L, i.e., the notification level of California, USA, which indicated a considerable threat to public health. Weak correlations were observed between N-nitrosamine yield and typical water quality parameters except for the dissolved organic nitrogen.     

Effect of cooling rate and laser process parameters on additive manufactured Fe–Ti–C metal matrix composites microstructure and carbide morphology

In this paper, laser additive manufacturing (LAM) of Fe–TiC composite coating on AISI 1030 carbon steel is investigated using a numerical and experimental method. In order to have a desired result using LAM, it is crucial to understand the effects of the process parameters’ values on the TiC morphology and microstructure. For this purpose, the LAM process is numerically simulated in order to calculate cooling rate and peak temperature. Experimental data and numerical results are in good agreement in terms of the phase development. Results show that cooling rate plays a crucial role in phase transformation in the clad, however, final microstructure strongly depends on the cooling rate and powder's chemical composition. Two main carbide morphologies (i.e. dendritic and particulate) are studied and relevant cooling rates are detected. Based on this paper and developed map, it is possible to control the cooling rate in order to achieve specific carbide morphologies in the clad. In this study, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are used to characterize clads’ microstructure.