The importance of in situ site loss in nature reserve selection: Balancing notions of complementarity and robustness

Because the threat of habitat destruction can never be entirely eliminated, there is a legitimate concern that some reserve networks, especially highly complementary ones with minimal species overlap, may be predisposed to severe losses in species representation if one or more core reserve sites are destroyed. In order to address this problem in a systematic way, we propose the use of two different optimization models for designing complementary reserve networks that are also highly robust to possible site losses. Given limited budgets, the first maximizes expected species representation over all possible site loss patterns while the second maximizes a combination of representation given all sites and remaining representation following the worst-case loss of a restricted subset of reserve sites. By incorporating reserve loss in fundamentally different ways, these two models provide a range of options in terms of information requirements, assumptions about risk aversion, and structural complexity. We compare both of these methods to a more standard approach, which completely ignores the inherent risk posed by reserve site loss. Results confirm that significantly more robust solutions can be obtained for a marginal decrease in initial species representation within the reserve system.     

Climate change might drive the invasive tree Robinia pseudacacia into nature reserves and endangered habitats

Static networks of nature reserves disregard the dynamics of species ranges in changing environments. In fact, climate warming has been shown to potentially drive endangered species out of reserves. Less attention has been paid to the related problem that a warmer climate may also foster the invasion of alien species into reserve networks. Here, we use niche-based predictive modelling to assess to which extent the Austrian Natura 2000 network and a number of habitat types of conservation value outside this network might be prone to climate warming driven changes in invasion risk by Robinia pseudacacia L., one of the most problematic alien plants in Europe.Results suggest that the area potentially invaded by R. pseudacacia will increase considerably under a warmer climate. Interestingly, invasion risk will grow at a higher than average rate for most of the studied habitat types but less than the national average in Natura 2000 sites. This result points to a potential bias in legal protection towards high mountain areas which largely will remain too cold for R. pseudacacia. In contrast, the selected habitat types are more frequent in montane or lower lying regions, where R. pseudacacia invasion risk will increase most pronouncedly.We conclude that management plans of nature reserves should incorporate global warming driven changes in invasion risk in a more explicit manner. In case of R. pseudacacia, reducing propagule pressure by avoiding purposeful plantation in the neighbourhood of reserves and endangered habitats is a simple but crucial measure to prevent further invasion under a warmer climate.     

The burden of genetic diversity

In general, species with large ecological amplitudes are equipped with high genetic diversities. In contrast, more specialised species with narrow ecological amplitudes show low levels of genetic diversity. Generalist species are mostly rather marginally affected by recent land-use changes; specialist can be supported by specific conservation measures. We argue that, in the light of Conservation Genetics, species being ecologically intermediate between these two extremes are the most seriously affected ones by recent environmental changes. Such species which formerly occurred in large population networks have to sustain their high level of genetic variability via gene flow. Today, species from the latter group are negatively affected by rapid habitat collapses causing sudden lacks of population interconnectivity. Therefore, species with intermediate habitat demands and originally high genetic diversity might be at highest risk due to inbreeding depressions.     

Do railway edges provide functional connectivity for plant communities in an urban context?

Functional connectivity is essential to maintaining biodiversity in fragmented landscapes but little attention has been given to structures that can provide it in an urban context. Using both the taxonomic and functional diversity of semi-natural grassland plant communities, we assessed the functional connectivity of linear transportation infrastructures in urban landscape. We sampled the vegetation at 71 study sites located along the edges of two railway lines. We hypothesised that if railways favour functional connectivity, then spatially connected communities should be more similar than disconnected communities. Therefore, we compared floristic dissimilarities between site pairs that were either connected or separated by a railway spatial break (overpass or station). As a further approach, we supposed that functional connectivity may attenuate the effect of urbanisation filters on plant communities. Thus we examined whether and how edges’ plant communities were influenced by urbanisation and compared our results to the patterns described in the literature. Functional connectivity was mainly maintained at railway stations, contrary to overpasses, which seemed to interrupt dispersal, demonstrating that railway edges provide connectivity for some but not all functional groups: this was only true for moderately mobile species. Surprisingly, railway edges did not seem to play an additional connective function for invasive species, the presence of which being strongly related to the urbanisation intensity and not influenced by spatial breaks along railways. Our study thus highlights the potential function of railway edges as corridors for common grassland plants. Landscape managers should include railways in green networks to improve connectivity in urban landscapes.     

密云水库不同林地配置下地表水水质状况分析

密云水库是北京市最重要的饮用水水源地,它为北京提供了近70%的生活用水,因此密云水库的水质保护成为了当前迫切需要解决的问题。为此,在密云县太师屯镇建立10个以不同造林模式配置的水源涵养林试验区,并构建径流小区。通过检测各径流小区地表水水质情况,进而找出发挥水文效益最佳的造林模式。运用综合指数法、模糊数学法和灰色关联法对数据进行分析后,得出:不同造林模式对地表水水质的影响很大,2号试验地的油松和黄栌混交林改善水质效果最佳,达到了国家Ⅰ类水标准,其他试验地的改善水质效果不佳,均差于2号试验地。由此可见,油松混交黄栌的造林模式为密云水源林的最佳造林模式,且该混交林树种的成活率均在90%以上,建议进行推广栽植。     

Woodland key habitats evaluated as part of a functional reserve network

Woodland key habitats (WKHs) represent a potentially cost-efficient means to protect biodiversity in managed forests. The Forest Act of Finland defines 13 habitat types of WKHs, which enjoy legal protection. It has been argued that WKHs are too small-sized and scattered in occurrence to be actually important in the maintenance of forest biodiversity. However, from the species’ perspective, WKHs form a network together with nature reserves. We evaluated the value and role of WKHs as a part of the whole reserve network using a graph-theoretical connectivity approach in three areas (ca. 500 km² each) located in Central Finland. The networks were formed separately for different habitat types and dispersal distances (ranging from 200 m to 25 km). We compared networks with and without WKHs, and thereby quantified the contribution of WKHs to overall network connectivity. We also examined the role of WKHs in the networks based on patch importance and network centrality measures. The results showed that the connectivity contributions of WKHs are tightly linked with the dispersal abilities of threatened species: WKHs enhance habitat connectivity, especially for species with an intermediate dispersal ability. For species with a poor dispersal ability, the protection of large set-asides would be a more efficient way to increase habitat connectivity than WKHs. WKH-based conservation seems to improve the connectivity of naturally rare and scattered habitat types relatively more than common habitat types, but in sparse networks a greater dispersal ability is required to gain enhanced connectivity than in dense ones. The connectivity value of WKHs can be understood as an emergent and scale-dependent property, appearing at the level of the entire functional network. Provided that the site characteristics of WKHs can be safeguarded, they can be a valuable and efficient addition to the reserve network.     

Calcareous fens in south Sweden. Previous use,effects of management and management recommendations

A report written in the Swedish language has been abridged and rewritten for foreign readers. Each calcareous fen site is a unique feature though it is possible to generalise such fens into five types according to soil type and most frequent plant communities. Previously most fen sites were used for hay and/or grazing, which gradually decreased from the middle of the 19th century and, since the 1950s has become very unusual. The effects of different management practices are still insufficiently known, observations on species are often contradictory and hence experimental studies are needed. The future management should be adjusted to the sensitivity of each site, the fen type, the main plant communities and the purposes of the preservation.     

Range size variation, nestedness and species turnover of orchid species along an altitudinal gradient on Réunion Island: Implications for conservation

Tropical oceanic islands contribute disproportionably for their area to global biodiversity and this is especially true for islands with strong altitudinal gradients. On these islands, species richness and composition usually change with altitude, but the way in which they do may vary from one system to the next. Better insights in how species richness and composition are related may have far-reaching conservation implications. At the one extreme, species composition of a species-poor site may be completely different from that of the most species-rich site. In this case, conservation of the species-poor site should be encouraged as it contains species that are not to be found elsewhere. At the other extreme, species composition of the species-poor sites may be a subset of the species-rich sites (i.e. nestedness or nested subsets). Focus on the most species-rich site may be sufficient to effectively conserve a maximum of species. In this study, we determined changes in species richness and composition of orchid species along an altitudinal gradient spanning more than 2500 m on Réunion Island (Mascarenes). A formal nestedness analysis was performed to investigate whether species-poor sites were a subset of species-rich sites and whether this was related to altitude. Differences in species composition along the altitudinal gradient were determined using two different measures of community similarity. The species-by-sites matrix was significantly nested when sorted by species richness, but not when sorted by altitude. Mean similarity indices were low at both low and high altitude sites, indicating significant turnover of orchid species. Our results suggest that reserve selection should be based on two basic principles: (1) maximize the number of vegetation zones in which reserves are to be placed and (2) within each zone, select the sites with the highest species richness. Given that at present only two nature reserves are present on the island, our results further suggest that they are not sufficient to effectively conserve the extremely high orchid diversity on Réunion Island.     

融合注意力机制的个体猪脸识别

随着机器视觉技术的发展,猪脸识别作为猪只个体识别方法之一受到广泛关注。为了探索非接触式的猪只个体精准识别,该研究通过深度学习模型DenseNet融合CBAM（Convolutional Block Attention Module）,建立改进的DenseNet-CBAM模型对猪脸进行识别。将DenseNet121模型进行精简,然后将CBAM注意力模块嵌入到精简的DenseNet121分类网络之前,以加强对关键特征的提取,实现猪脸图像的分类。以随机采集的1 195张猪脸图像作为数据集对本文模型进行测试。结果表明,DenseNet-CBAM模型对个体猪脸识别的准确率达到99.25%,模型参数量仅为DenseNet121的1/10;与ResNet50、GoogLetNet和MobileNet模型相比,DenseNet-CBAM的识别准确率分别提高了2.18、3.60和23.94个百分点。研究结果可为智能化养殖过程非接触式个体识别提供参考。     

The cost of postponing biodiversity conservation in Mexico

Though Neotropical countries are the most species rich in the world, their biodiversity is threatened by the loss of native vegetation. Land conversion in Mexico during the last 30 years has been extensive and is representative of that of other developing countries. However, the effects of land use change on the required size and configuration of an adequate biological conservation area network are largely unknown. It is shown here that endemic mammals in Mexico could have been protected considerably more economically if a conservation plan had been implemented in 1970 than is possible today due to extensive conversion of primary habitats. Analysis of the distributions of 86 endemic mammal species in 1970, 1976, 1993, and 2000 indicates that the distributions of 90% of the species shrank during this 30-year period. At each time step, optimal conservation area networks were selected to represent all species. 90% more land must be protected after 2000 to protect adequate mammal habitat than would have been required in 1970. In addition, under a realistic conservation budget, 79% fewer species can be represented adequately in a conservation area network after 2000 compared to 1970. This provides an incentive for rapid conservation action in Mexico and other biodiversity hotspots with comparable deforestation rates, including Burma, Ecuador, Indonesia, the Philippines, and Sri Lanka. Due to ongoing habitat degradation, the efficiency of a conservation plan decreases with delays in its implementation.     

When the species is also a habitat: Comparing the predictively modelled distributions of Lophelia pertusa and the reef habitat it forms

Internationally there is political momentum to establish networks of marine protected areas for the conservation of threatened species and habitats. Practical implementation of such networks requires an understanding of the distribution of these species and habitats. Predictive modelling provides a method by which continuous distribution maps can be produced from limited sample data. This method is particularly useful in the deep sea where a number of biological communities have been identified as vulnerable ‘habitats’, including Lophelia pertusa reefs. Recent modelling efforts have focused on predicting the distribution of this species. However the species is widely distributed where as reef habitat is not. This study uses Maxent predictive modelling to investigate whether the distribution of the species acts as a suitable proxy for the reef habitat. Models of both species and habitat distribution across Hatton Bank and George Bligh Bank are constructed using multibeam bathymetry, interpreted substrate and geomorphology layers, and derived layers of bathymetric position index (BPI), rugosity, slope and aspect. Species and reef presence records were obtained from video observations. For both models performance is fair to excellent assessed using AUC and additional threshold dependant metrics. 7.17% of the study area is predicted as highly suitable for the species presence while only 0.56% is suitable for reef presence, using the sensitivity–specificity sum maximisation approach to determine the appropriate threshold. Substrate is the most important variable in the both models followed by geomorphology in the RD model and fine scale BPI in the SD model. The difference in the distributions of reef and species suggest that mapping efforts should focus on the habitat rather than the species at fine (100 m) scales.     

Restoration of plant diversity on ditch banks: Seed and site limitation in response to agri-environment schemes

Recently it has become clear that seed limitation is probably a much more important factor in plant recovery than has often been recognized. However, in practice, restoration measures that are focussed on decreasing site limitation may actually increase seed limitation. We tried to determine whether the effects of restoration measures affect site or seed limitation or both. An experiment was set up on ditch banks in the Netherlands which applied agri-environment schemes (AES). To investigate whether nature reserves (seed source) can improve species diversity on the surroundings and to what extent AES is improving this function, we studied the plant diversity (presence of individual species and species richness) of ditch bank vegetations in relation to increasing distance from nature reserves. The presence or absence and species richness of 25 target plants were assessed in 26 ditch banks with AES and 36 non-AES at 15 plots each differing in distance to a nature reserve. Data were analyzed using a Hierarchical Generalized Linear Model (HGLM) with species richness and presence of individual species as response variables and distance to nature reserve and application of AES as factors, controlling for possible confounding factors. Results were interpreted as the effects of AES on seed and site limitation of the species. The results showed that plant diversity decreased significantly with distance from source populations. There were considerable differences in species diversity between AES and non-AES ditch banks, with the former showing greater plant diversity especially in the first 200 m from nature reserves. Presences of all individual species decreased with distance to nature reserve, but the strength of this relationship and the AES effects differed among species. AES ditch banks had lower site limitations for most plant species, but did not have lower seed limitation.     

Endemism and evolutionary history in conflict over Madagascar’s freshwater conservation priorities

Regional-scale biodiversity indicators provide important criteria for the selection of protected areas in conservation, but their application is often hindered by a lack of taxonomic knowledge. Moreover, different indicators include different types of information, sometimes leading to divergent conservation priorities. Madagascar tops the world list of biodiversity hotspots and much conservation effort has been directed toward its threatened plants and vertebrates. In contrast, its highly diverse freshwater invertebrate fauna has received comparatively little conservation attention. We conducted an inventory of Malagasy adephagan water beetles (Coleoptera, Dytiscidae, Noteridae, Gyrinidae, Haliplidae) using a combined morphological and molecular approach. In total, 2043 beetles from 153 sites were sequenced for cytochrome oxidase subunit I (cox1), and species delimitation was carried out using the coalescent-based GMYC model. Phylogenetic relationships of the resulting entities were established using cox1 combined with partial 16S rRNA and 28S rRNA sequences. Ten national parks were assessed for their species richness, phylogenetic diversity (PD) and endemism. We were particularly interested in the contribution of endemic species to PD. Congruence between molecular and taxonomic identifications was high (91%), with 69% of sampled species endemic to Madagascar. Interestingly, we found that PD at a site was negatively correlated to the proportion of endemic species, most likely because endemics are the result of recent radiations with relatively little branch-length contribution to the measure of PD. This suggests that ranking sites for conservation priority based solely on PD potentially disfavor endemic species by underrating areas where the evolutionary process is most active.     

延河流域典型物种分布预测模型比较研究

物种分布预测一直以来都是生态学研究的重要内容之一.应用生态学的发展为物种分布预测提供了众多强有力的模型,在推进物种分布预测进展的同时,也增加了合适模型选择的难度.评价和比较不同模型的预测效果,对于模型的选择和应用具有非常重要的意义.以黄土丘陵区延河流域为研究区,采用R语言和BIOMOD程序包为平台,选择人工神经网络(artificial neural networks,ANN)等9个较常用的物种分布模型,比较它们在物种分布预测精度上的差异,为物种分布预测模型的选择提供依据,也为进一步预测未来气候变化情景下物种空间分布的变化奠定基础.研究结果表明,不同模型对不同物种的模拟精度差异明显.根据Kappa,TSS和Roc评价方法,9个模型对百里香(Thymus mongolicus)分布的预测精度最高;对铁杆蒿(Artemisia gmelinii)分布的模拟精度最差;而对其余物种分布的模拟精度均比较理想,其中以随机树RF模型最好.     

The ecological effectiveness of protected areas: The United Kingdom

Given the importance placed on protected areas, determining their effectiveness in representing and maintaining biodiversity is a core issue in conservation biology. Nonetheless, frameworks identifying the breadth of issues associated with this effectiveness, and case studies of how well these are understood in particular regions, remain lacking. In this paper, we provide such a framework and an overview of the current state of knowledge of the ecological effectiveness of protected areas in the United Kingdom. Arguably, better data are available to address such issues in this region than anywhere else in the world. Nonetheless, studies remain scarce and have focussed foremost on the, rather narrow, issue of the effectiveness of management actions on individual sites in order to deliver fixed conservation objectives and discharge statutory responsibilities. Some attention has also been paid to how well the regional collection or portfolio of protected areas performs, particularly in capturing biodiversity features. Work on the extent to which protected areas in the United Kingdom form effective functional networks is in its infancy, but initiatives are under development. We identify some of the questions about the effectiveness of protected areas to which answers need to be known at the site, portfolio and network levels, and how significant progress might be achieved in addressing these.     

Correlation between Environmental Conditions and the Distribution of Mosses Exposed to Urban Air Pollutants

Moss surveys have several advantages over conventional depositionmonitoring based on precipitation, and allow the study of regional differences and temporal trends of airborne pollution. The purposes of this study were to: (i) describe the moss species growing in one of the largest industrial cities in Asia, (ii) document edaphic and atmospheric conditions at each site, (iii) collect materials and data for a program of regular moss monitoring, previously lacking in the Far East, (iv) uncover correlations among atmospheric and edaphic factors expected to influence moss growth. As a result, a total of fifteen moss species were recorded in twenty-five sites in Seoul, Korea, and most sites had four or five species. Each species' density was affected by soil parameters, but density of Pogonatum nessii and Taxiphyllum taxirameum was also affected by CO. In contrast, SO₂ was the only environmental variablethat significantly affected the composition of moss communities. On the whole, species diversity rather than abundance of specific moss species might be a good indicator of atmospheric contamination in Seoul. This investigation will help fill the gap in knowledge of the interactions between environmental pollution and moss vegetation under field conditions.     

How much do site age, habitat structure and spatial isolation influence the restoration of rainforest beetle species assemblages?

Reforestation has been suggested as a way to mitigate the effects of tropical rain forest loss. However, factors influencing the successful colonisation of biota into newly created rainforest are poorly understood. We assessed beetle species assemblages with flight interception traps, in sites undergoing rainforest restoration across the largely cleared landscape of the Atherton Tablelands in north-eastern Queensland, Australia. There were two levels of site age (2-4 years and 6-17 years) and two distances from intact rainforest (adjacent and >0.9 km), with six sites in each treatment, together with six reference sites in each of pasture and small rainforest remnants (n = 36 sites). Multivariate metrics were used to assess the restored sites’ relative similarity to pasture and rainforest, in terms of both physical habitat structure and beetle species composition within ten family groups. Older restoration sites were structurally most similar to rainforest. Older sites and those adjacent to rainforest had a more rainforest-like beetle species composition (without significant interaction). However, even the closer and older sites had a substantially lower abundance and richness of rainforest-associated beetles than did rainforest. Age effects were generally stronger than distance effects, with the latter appearing to be entirely driven by rare rainforest species. Beetle assemblage similarity to rainforest was more strongly correlated with structural similarity to rainforest than with age, except within older sites. The use of revegetation techniques which lead to more rainforest-like structural conditions appears to be of over-riding importance in catalysing the rapid acquisition of volant rainforest beetle assemblages in the initial stages of restoration.     

The role of nest sites in limiting the numbers of hole-nesting birds: A review

The breeding densities of many bird-species which nest in tree cavities are in some areas limited by shortage of sites. This is evident from circumstantial evidence in which the numbers of breeding pairs in different areas correlate with the numbers of local nest sites, or where changes in the numbers of nest sites resulting from natural processes or human action are followed by changes in the numbers of pairs. It is also shown experimentally, where nest site provision or removal has been followed by a corresponding change in breeding density.

When nest boxes were provided, they were often occupied in the same year, leading to an immediate rise in breeding density. This implied that surplus birds were available in the vicinity and able to take them up. In future years, pair numbers often increased further but eventually they levelled off. This implied that, at this higher level, other limiting factors came into play. Experiments on nest site provision thus provide examples of different factors acting successively to limit breeding density at different levels.

By constraining breeding density, shortage of nest sites not only prevents some birds from breeding, but must also limit the total numbers of breeders and non-breeders, because no population can increase beyond a certain point, when the production of young is limited. Once all available nest sites are occupied, reproduction is inevitably density-dependent with respect to the total population of breeders and non-breeders.

Because several bird species can use the same type of site, competition is frequent, and the numbers of dominant species can affect the numbers and distribution of others. In extreme situations, a species may be totally absent from areas where all suitable nest sites are occupied by dominant competitors. In less extreme situations, the numbers of a subordinate species may vary from year to year or from place to place in inverse relation to the numbers of a dominant species. Both these situations can be changed by the provision of extra sites.

In managed woods and modern tree plantations, most hole-nesting bird species are excluded or kept at extremely low levels by shortage of nest sites. This is a direct result of forestry practice, which usually entails removal of the old and dying trees that normally provide the sites. The problem can be rectified by allowing a number of old and dead trees to remain in managed forests, or (on a more local scale) by the provision of nest boxes. By appropriate design and positioning of the boxes, the most desired species can be favoured.     

Indigenous and scientific knowledge: the choice and management of cultivation sites by bedouin in Upper Egypt

Abstract. This paper investigates the ways in which some bedouin in the Nubian Desert of southeastern Egypt take decisions about both the choice of site for cultivation and the subsequent management of their soils. It explores the complementarity of formal and informal sciences and how each might profitably inform the other. Results show that the bedouin understand the physical limitations and nutrient supply properties of soils, but not aspects such as pH. Decisions on the choice of cultivation site are often made with regard to other perceived risks, such as soil loss and intermittent inundation, rather than just soil quality. It is also apparent that there exists among bedouin a plurality of indigenous knowledge mediated by factors such as experience, wealth levels, household circumstances and production priorities. Understanding indigenous knowledge is essential in helping to develop better use of the soil in this area, about which little is known and which has only a short history of small scale cropping.