Identifying multiple wildlife species-crop interactions using network analysis

Managing crop damage by wildlife is a complex challenge in agrarian-wildlife landscapes. Losses to farmers and their negative attitude towards crop-raiding wildlife, compromise wildlife conservation and farmer-wildlife coexistence. Priority crop types, crop-raiding wildlife and socio-ecological factors are highly integrated. Here we use cross-sectional network analysis as a conservation planning tool to simultaneously identify the crop types used by crop-raiding wildlife, and evaluate the importance of these crop-wildlife interactions relative to the socio-ecological factors that affect these interactions. The most vulnerable crops were maize, millet and fruit trees, while the most problematic crop-raiding wildlife were African elephant, bushpig, hippo, warthog and red-billed quelea. Crop damage declined with countermeasure effectiveness, farm size, and distance from river to farm, but increased with richness of attractive crops. Undamaged crops included cash crops, such as chili, onion, ginger, lemon grass and garlic. Applying network analysis to different crops and damage scenarios enables identification of the most important and influential crops, crop-raiding wildlife and socio-ecological factors needed to develop effective crop protection strategies.     

Marine biodiversity: patterns, threats and conservation needs

Marine biodiversity is higher in benthic rather than pelagic systems, and in coasts rather than the open ocean since there is a greater range of habitats near the coast. The highest species diversity occurs in the Indonesian archipelago and decreases radially from there. The terrestrial pattern of increasing diversity from poles to tropics occurs from the Arctic to the tropics but does not seem to occur in the southern hemisphere where diversity is high at high latitides. Losses of marine diversity are highest in coastal areas largely as a result of conflicting uses of coastal habitats. The best way to conserve marine diversity is to conserve habitat and landscape diversity in the coastal area. Marine protected areas are only a part of the conservation strategy needed. It is suggested that a framework for coastal conservation is integrated coastal area management where one of the primary goals is sustainable use of coastal biodiversity.     

Potato nematodes and their control measures: a review

Root and tuber crops are the most important commodities produced in many subtropical and tropical regions. Potato, Solanum tuberosum L. is a major food crop in many countries and it is produced in any significant amount in developed countries. Certain nematodes recognised as major parasites of potato are cyst, root-knot and lesion nematodes. Losses vary depending upon the cultivar and predominant environmental conditions. Losses can reach 25% or more and these losses consist of direct damage to the plant as well as reduction in tuber quality. Also, anatomical studies proved that the root-knot nematode, Meloidogyne incognita, caused giant cells as feeding sites in the stele region of potato roots accompanied with crushed and deformed xylem and vessel elements. Therefore, control measures depend upon the use of resistant cultivars, rotation with non-host plants, hot water treatment of infected tubers before planting, some biocontrol methods and utilisation of the nematicides as contact or as dips.     

Nest loss in capercaillie and black grouse in relation to the small rodent cycle in southeast Norway

Summary The relationship between nest loss in boreal forest grouse and the fluctuations in small rodents was studied at Varaldskogen in southeast Norway during 1979–1986, covering two complete rodent cycles. Nest loss in capercaillie (N=174) and black grouse (N=81) was calculated according to Mayfield (1975) based on nests from radio-equipped hens (N=77) and nests found by other methods (N=178). Small rodent density was measured by snap trapping during spring and autumn. Losses varied as predicted by the classical alternative prey hypothesis (Hagen 1952 and Lack 1954, as elaborated by Angelstam et al. 1984): high losses during rodent crash years (85.5% capercaillie, 51% black grouse), and smaller losses during peak years (54.5% capercaillie, 32.5% black grouse). Losses were inversely related to autumn abundance of rodents in capercaillie (P<0.05), but the correlation was not significant for black grouse (0.10<P<0.20). In capercaillie, the only species with an adequate sample for analysis, no relationship was detected between spring density of rodents and nest loss. Losses during the prepeak years were nearly as high as during crash years, a result inconsistent with the model. We conclude that the numerical response of predators to their cyclic main prey (i.e. small rodents) probably play a main role during the low phase and prepeak year, whereas the dietary shift is most important during the peak and crash year of the cycle.     

Soluble and slow-release PK-fertilizers for seedlings and transplants ofPicea sitchensis andPicea abies in two English nurseries

Summary In a heathland nursery on an acid sandy podsol and in a nursery on moderately acid agricultural land, four PK fertilizers were compared with superphosphate alone, using seedlings and transplants of Sitka sprucePicea sitchensis and Norway sprucePicea abies as test crops. The four fertilizers were: 1) a compound prepared from KCl and superphosphate (KCl/superphosphate), 2) the same compound supplemented by three summer topdressings of potassium nitrate, 3) potassium dihydrogen phosphate, 4) potassium metaphosphate. Except for potassium nitrate all fertilizers were applied in the spring before sowing or transplanting.Mid-season analyses (confined to Sitka spruce seedlings) showed that the effectiveness of different fertilizers depended on the rainfall pattern during growth. Phosphorus and potassium were leached less and nutrients used more efficiently with potassium metaphosphate than with KCl/superphosphate. Potassium nitrate applied on three occasions during the summer to plots with KCl/superphosphate maintained the best growth and largest K-concentrations in the seedlings. Differences between fertilizers were small for transplants at the heathland nursery and for all crops at the nursery on an agricultural-type soil. Losses of P and K by leaching on the sandy podsol both decreased in the order KCl/superphosphate > or=potassium dihydrogen phosphate > potassium metaphosphate.     

Avian use of perennial biomass feedstocks as post-breeding and migratory stopover habitat

Increased production of biomass crops in North America will require new agricultural land, intensify the cultivation of land already under production and introduce new types of biomass crops. Assessing the potential biodiversity impacts of novel agricultural systems is fundamental to the maintenance of biodiversity in agricultural landscapes, yet the consequences of expanded biomass production remain unclear. We evaluate the ability of two candidate second generation biomass feedstocks (switchgrass, Panicum virgatum, and mixed-grass prairie) not currently managed as crops to act as post-breeding and fall migratory stopover habitat for birds. In total, we detected 41 bird species, including grassland specialists and species of state and national conservation concern (e.g. Henslow's Sparrow, Ammodramus henslowii). Avian species richness was generally comparable in switchgrass and prairie and increased with patch size in both patch types. Grassland specialists were less abundant and less likely to occur in patches within highly forested landscapes and were more common and likely to occur in larger patches, indicating that this group is also area-sensitive outside of the breeding season. Variation in the biomass and richness of arthropod food within patches was generally unrelated to richness and abundance metrics. Total bird abundance and that of grassland specialists was higher in patches with greater vegetation structural heterogeneity. Collectively, we find that perennial biomass feedstocks have potential to provide post-breeding and migratory stopover habitat for birds, but that the placement and management of crops will be critical factors in determining their suitability for species of conservation concern. Industrialization of cellulosic bioenergy production that results in reduced crop structural heterogeneity is likely to dramatically reduce the suitability of perennial biomass crops for birds.     

The impact of humans on the nitrogen cycle,with focus on temperate arable agriculture

The 6 billion people alive today consume about 25 million tonnes of protein nitrogen each year, a requirement that could well increase to 40–45 million tonnes by 2050. Most of them ultimately depend on the Haber-Bosch process to fix the atmospheric N₂ needed to grow at least part of their protein and, over the earth as a whole, this dependency is likely to increase. Humans now fix some 160 million tonnes of nitrogen per year, of which 98 are fixed industrially by the Haber-Bosch process (83 for use as agricultural fertilizer, 15 for industry), 22 during combustion and the rest is fixed during the cultivation of leguminous crops and fodders. These 160 million tonnes have markedly increased the burden of combined nitrogen entering rivers, lakes and shallow seas, as well as increasing the input of NH₃, N₂O, NO and NO₂ to the atmosphere. Nitrogen fertilizers give large economic gains in modern farming systems and under favourable conditions can be used very efficiently. Losses of nitrogen occur from all systems of agriculture, with organic manures being particularly difficult to use efficiently. Although nitrate leaching has received much attention as an economic loss, a cause of eutrophication and a health hazard, gaseous emissions may eventually prove to be the most serious environmentally. Scientists working on the use and fate of nitrogen fertilizers must be careful, clear headed and vigilant in looking for unexpected side effects.     

Losses of Alcohol and Alcohol Dehydrogenase Activity in Germinating Seeds

Losses of alcohol, which had accumulated under anaerobic conditions,occurred during the germination of several species of seedswhich could not be attributed to the volatility of the alcohol.It is suggested that utilization of the alcohol by the seedsmay occur. From the seeds, an active alcohol dehydrogenase,which is mainly confined to the cotyledons in pea seeds, canbe extracted. The activity of the enzyme decreases as the cotyledonsgrow older during germination. The properties of the enzymehave been investigated.     

Determination of oestrogen monoglucuronides by the Brown method

In the Brown (Brown, 1955; Brown, Bulbrook & Greenwood, 1957) procedure for the determination of urinary oestrogens, losses may occur during the hydrolysis of the oestrogen conjugates and during the purification of the oestrogens thus formed. Losses during the latter stages were measured previously by adding free oestrogens to the hydrolysed urine. In the present study losses during acid and enzyme hydrolysis were measured by adding synthetic oestrogen monoglucuronides to urine.     

Conflict of Interest Between People and Baboons: Crop Raiding in Uganda

Much has been written about insect damage to standing crops, but an area that has received little attention within agricultural development, conservation, and primatological literature is that of primates and the potential damage they can cause to farmers' fields. This is likely to become an increasingly important issue for people interested in primates, as conservation projects adopt a more integrated approach to take account of local people's perspectives and needs. The aim of this paper is to examine the impact of crop raiding by primates, particularly baboons, on farmers living around the southern edge of the Budongo Forest Reserve, Uganda. I use data gathered during monthly farm surveys and informal discussion groups, along with time budget data, to demonstrate that 1) baboons can cause extensive damage to field crops, such as maize and cassava; 2) proximity of the farm to the forest edge and the presence or absence of neighboring farms affect the likelihood of any farm sustaining crop damage from baboons; and 3) in addition to the direct costs associated with crop losses attributed to baboon foraging activity, there are indirect costs of baboon crop raiding such as increased labor demands to protect crops from them and, occasionally, to replant crop stands badly damaged by baboons. These results have important implications for future primate conservation policy and practice.     

The Importance of Rotational Crops for Biodiversity Conservation in Mediterranean Areas

Nowadays we are seeing the largest biodiversity loss since the extinction of the dinosaurs. To conserve biodiversity it is essential to plan protected areas using a prioritization approach, which takes into account the current biodiversity value of the sites. Considering that in the Mediterranean Basin the agro-ecosystems are one of the most important parts of the landscape, the conservation of crops is essential to biodiversity conservation. In the framework of agro-ecosystem conservation, farmland birds play an important role because of their representativeness, and because of their steady decline in the last Century in Western Europe. The main aim of this research was to define if crop dominated landscapes could be useful for biodiversity conservation in a Mediterranean area in which the landscape was modified by humans in the last thousand years and was affected by the important biogeographical phenomenon of peninsula effect. To assess this, we identify the hotspots and the coldspots of bird diversity in southern Italy both during the winter and in the breeding season. In particular we used a scoring method, defining a biodiversity value for each cell of a 1-km grid superimposed on the study area, using data collected by fieldwork following a stratified random sampling design. This value was analysed by a multiple linear regression analysis and was predicted in the whole study area. Then we defined the hotspots and the coldspots of the study area as 15% of the cells with higher and lower value of biodiversity, respectively. Finally, we used GAP analysis to compare hotspot distribution with the current network of protected areas. This study showed that the winter hotspots of bird diversity were associated with marshes and water bodies, shrublands, and irrigated crops, whilst the breeding hotspots were associated with more natural areas (e.g. transitional wood/shrubs), such as open areas (natural grasslands, pastures and not irrigated crops). Moreover, the results underlined the negative effects of permanent crops, such as vineyards, olive groves, and orchards, in particular during the winter season. This research highlights the importance of farmland areas mainly for wintering species and the importance of open areas for breeding species in the Mediterranean Basin. This may be true even when the species’ spatial distribution could be affected by biogeography. An important result showed that the hotspots for breeding species cannot be used as a surrogate for the wintering species, which were often not considered in the planning of protected areas.     

Habitat selection and segregation by two sympatric lagomorphs: the case of European hares (<Emphasis Type="Italic">Lepus europaeus</Emphasis>) and Eastern cottontails (<Emphasis Type="Italic">Sylvilagus floridanus</Emphasis>) in northern Italy

In northern Italy, the native European hare (Lepus europaeus) and the introduced Eastern cottontail (Sylvilagus floridanus) can occur together at a local scale, as a result of cottontail introduction and expansion into the European hare range. Hare populations are limited in Italy by habitat loss, diseases, and most important by overhunting, and many areas within hare range in northern Italy are undergoing increasing anthropogenic impact. Therefore, quantitative studies on resource selection and exploitation by both species will be of great interest to evaluate the degree of habitat overlap and to search for exploitation competition evidences. We studied habitat selection during resting time by both species in two areas where they occur alone and in one area where they occur together. Habitat selection by the two species was examined at micro- and macro-habitat scales during autumn–winter and spring–summer. Both species selected ecotonal zones between arboriculture stands and crops and between arboriculture stands and spontaneous vegetation (i.e., herbaceous, bush, and woody permanent species), which were the less available in the area of sympatry. No habitat shifts were evident at macro-habitat level because the two species showed a differential micro-habitat use within patches. On the whole, it seems that habitat heterogeneity promoted daytime segregation between the two species. In particular, edges between crops and canopy habitats should be improved, thus reducing chance of intra- and inter-specific encounters.     

覆盖作物的种植现状及其对下茬作物生长和土壤环境影响的研究进展

覆盖作物指的是在农业生产间隙种植,使土壤在时间或空间上减少或避免裸露的一种作物。其能使农田土壤免受风蚀、水蚀和人为扰动的影响,被认为是一种新型的保护性耕作方式。本文简要介绍了农田覆盖作物的种植管理情况,包括种植品种、耕作模式和绿肥作物的灭生还田方式等,可为推广覆盖作物在农田休闲期的高效大面积种植提供参考。基于国内外研究综述了绿肥种植对经济作物、土壤质量、杂草抑制、温室气体排放和土壤微生物等的影响及研究进展,阐明了覆盖作物对农田生态系统的诸多益处。尽管覆盖作物存在局限性,例如短期收益不明显、管理措施不当会造成作物减产等,但其在改善土壤质量、实现农业可持续发展方面仍然具有重要的应用价值。     

Bee and non-bee pollinator importance for local food security

Pollinators are critical for food security; however, their contribution to the pollination of locally important crops is still unclear, especially for non-bee pollinators. We reviewed the diversity, conservation status, and role of bee and non-bee pollinators in 83 different crops described either as important for the global food market or of local importance. Bees are the most commonly recorded crop floral visitors. However, non-bee pollinators are frequently recorded visitors to crops of local importance. Non-bee pollinators in tropical ecosystems include nocturnal insects, bats, and birds. Importantly, nocturnal pollinators are neglected in current diurnal-oriented research and are experiencing declines. The integration of non-bee pollinators into scientific studies and conservation agenda is urgently required for more sustainable agriculture and safeguarding food security for both globally and locally important crops.     

Age-related and origin-related control of the numbers of plasmodesmata in cell walls of developing Azolla roots

Plasmodesmata were counted in the longitudinal and transverse walls in developmental sequences of merophytes in roots of Azolla pinnata R.Br. The differences between certain categories of longitudinal wall were traced to factors that govern the surface area of the cell plates, the density of plasmodesmata (number per unit area of cell plate), and the amount by which each type of plate expands. No evidence for secondary augmentation of plasmodesmatal numbers after the cell-plate stage of development was found, but plasmodesmata are lost from the walls of sieve and xylem elements during their differentiation. Losses caused by cell separation occur in other tissues. The relatively high density of plasmodesmata in transverse walls is based not so much on a high density in the cell plates as on the relatively low expansion that these walls undergo. There appears to be a compensatory mechanism that relates initial plasmodesmatal density to the future expansion of the cell plate. The root shows determinate growth, the apical cell dividing about 55 times. Beginning at about the 35th division there is a progressive failure to maintain the plasmodesmatal frequencies that were developed in earlier cell divisions in the apical cell. The divisions that occur within the later-produced merophytes also show progressive diminution of plasmodesmatal numbers. The result is that the apex of the root, and particularly the apical cell, becomes more and more isolated symplastically, a phenomenon which could account for its limited lifespan and the determinate growth pattern of the root.     

Denitrification in field soils

Summary Recent denitrification research is reviewed to answer questions a) how much N is lost from the soil as N₂ and N₂O and b) how do agronomic practices affect this loss? The methods used to quantify denitrification are also discussed. Gaseous losses of inorganic N range between the equivalent of 0 to 20 per cent of the fertilizer N applied to arable soils and 0–7 per cent on grassland soils. Losses are greater on undrained land and also after using direct drilling to establish arable crops.Appendix 1 summarizes reported measurements of gaseous N losses.Introductory lecture     

Breakdown of DNA in X-Irradiated Escherichia coli

A comparison of differences in incorporation and loss of radio-activity between two strains of Escherichia coli shows that: (a) three times as much irradiation is necessary to produce the same reduction in incorporation of H³-thymidine in B/r, the resistant strain, as in B_{s - 1}, the sensitive one; (b) radioactivity is lost from the DNA of previously labeled bacteria during the first few cell generations after X-ray exposure, and even though the initial rate of loss is similar for all strains, the sensitive one loses much more label; (c) loss of DNA is a complicated function of dose. Losses increase with dose up to 25 or 50 kr in both strains; with higher doses, losses decrease in B_{s - 1} but are unchanged in B/r. Since in both strains labeled RNA is retained in irradiated cells, lysis has not occurred but the DNA is broken down into small pieces which leak from each cell. Losses from either strain do not occur at ice-bath temperature, indicating that breakdown is a function of metabolic processes. A proposed mechanism for X-ray damage and repair is advanced.     

An assessment of the effect of harvest time and harvest method on biomass loss for Miscanthus × giganteus

This study examines the amount of biomass loss occurring in Miscanthus × giganteus crop at harvest. The study assesses loss incurred as a direct result of the harvest systems employed to collect the material along with examining how the time of harvest effects the amount of loss occurring over the spring harvest window. Pre harvest losses of 4.8–5.1% were measured prior to harvest. There was no significant difference between pre harvest loss and post harvest loss when a self‐propelled forage harvester fitted with a maize harvesting header was used to harvest the crop. The use of a conditioner mower and baler significantly increased crop losses to 9.4–14.1%. This demonstrates that correct selection of the harvest system can significantly increase biomass recovery. Additional losses were measured at headlands when the mower/baler system was used, but headland losses will not occur when self‐propelled forage harvesters are utilized. Losses were significantly greater in the area beside the swath after the baler pass when compared to prior to baling. This study has shown that correct selection of harvest systems can significantly increase biomass recovery, with no significant difference in pre harvest loss or harvest loss occurring as a result of cutting the M. × giganteus crop at different dates during the harvest window (March 1st, March 25th, April 21st).     

Some remarks on the determination of acid-detergent fibre in feeds with cetyltrimethylammonium bromide versus determination of detergent fibre with alkylarylsulfonic acid

A comparative evaluation of the determination of acid-detergent fibre (ADF) according to Van Soest and of a modified procedure for the determination of detergent fibre (DF) was performed on 54 forage samples. Losses of cellulose shown to occur during ADF preparation can be avoided by the DF procedure. Despite this finding, true cellulose-contents could be calculated from ADF and ADL, because of non-lignocellulosic contaminants compensating numerically for the cellulose losses.     

Human–hamadryas baboon (Papio hamadryas) conflict in the Wonchit Valley,South Wollo,Ethiopia

Understanding the extent of human–primate conflict is crucial to the development of conservation and management strategies. We carried out this study in an unprotected area of central Ethiopia to examine the magnitude of human–hamadryas baboon (Papio hamadryas) conflict and to assess the attitude of local farmers towards baboons in Wonchit Valley. In 2014, we interviewed 119 adult respondents using a structured questionnaire. Local farmers considered hamadryas baboons to be the major pest in the area. All respondents reported that hamadryas baboons caused crop raiding and small livestock predation in the region. Respondents reported that a shortage of fruit producing wild trees and ready availability of crops were the main causes of conflict between farmers and hamadryas baboons. We found that hamadryas baboons damaged cereal crops at dusk and dawn during full moonlight, and most (89.9%) respondents claimed that they were not interested in hamadryas baboon conservation. Our results indicate that human–hamadryas baboon conflict has a strongly negative impact on both baboon conservation and local farmers. We suggest that to mitigate the human–hamadryas baboon conflict, job opportunities such as beekeeping should be introduced in the region.