Structural patterns and biodiversity in burned and managed Aleppo pine stands

Increasing anthropic pressure is making forest fires more frequent in the Mediterranean Basin and therefore affecting the response of native flora and fauna. Two large fires occurred in summer, 1994, in the Southeastern Iberian Peninsula. Aleppo pine, the main tree species, regenerated naturally after the fire. In this study we are interested in strategies for maximizing Aleppo pine tree recovery and conservation of its ecosystem. We performed thinning and pruning in the pine tree stands 5 and 10 years after the fire and took measurements on structural patterns and plant diversity using several indices. In addition, we measured macro-lichen and faunal diversity indirectly. Results show significant differences between treated-burned plots and untreated-unburned plots. The plots thinned 10 years after the fire and the unburned plots (mature stands) showed a regular, non-aggregated distribution and a low diameter differentiation. Also, these plots showed similar plant diversity values. The silvicultural treatments did not significantly affect the fauna and lichen index values. The high intensity of thinning and late pruning applied to young Aleppo pine stands improved the structural pattern and plant diversity.     

Respiration acclimation contributes to high carbon-use efficiency in a seasonally dry pine forest

Predictions of warming and drying in the Mediterranean and other regions require quantifying of such effects on ecosystem carbon dynamics and respiration. Long‐term effects can only be obtained from forests in which seasonal drought is a regular feature. We carried out measurements in a semiarid Pinus halepensis (Aleppo pine) forest of aboveground respiration rates of foliage, R_f, and stem, R_t over 3 years. Component respiration combined with ongoing biometric, net CO₂ flux [net ecosystem productivity (NEP)] and soil respiration measurements were scaled to the ecosystem level to estimate gross and net primary productivity (GPP, NPP) and carbon‐use efficiency (CUE=NPP/GPP) using 6 years data. GPP, NPP and NEP were, on average, 880, 350 and 211 g C m^?2 yr^?1, respectively. The above ground respiration made up half of total ecosystem respiration but CUE remained high at 0.4. Large seasonal variations in both R_f and R_t were not consistently correlated with seasonal temperature trends. Seasonal adjustments of respiration were observed in both the normalized rate (R₂₀) and short‐term temperature sensitivity (Q₁₀), resulting in low respiration rates during the hot, dry period. R_f in fully developed needles was highest over winter–spring, and foliage R₂₀ was correlated with photosynthesis over the year. Needle growth occurred over summer, with respiration rates in developing needles higher than the fully developed foliage at most times. R_t showed a distinct seasonal maximum in May irrespective of year, which was not correlated to the winter stem growth, but could be associated with phenological drivers such as carbohydrate re‐mobilization and cambial activity. We show that in a semiarid pine forest photosynthesis and stem growth peak in (wet) winter and leaf growth in (dry) summer, and associated adjustments of component respiration, dominated by those in R₂₀, minimize annual respiratory losses. This is likely a key for maintaining high CUE and ecosystem productivity similar to much wetter sites, and could lead to different predictions of the effect of warming and drying climate on productivity of pine forests than based on short‐term droughts.     

Identifying practical indicators of biodiversity for stand-level management of plantation forests

Identification of valid indicators of biodiversity is a critical need for sustainable forest management. We developed compositional, structural and functional indicators of biodiversity for five taxonomic groups—bryophytes, vascular plants, spiders, hoverflies and birds—using data from 44 Sitka spruce (Picea sitchensis) and ash (Fraxinus excelsior) plantation forests in Ireland. The best structural biodiversity indicator was stand stage, defined using a multivariate classification of forest structure variables. However, biodiversity trends over the forest cycle and between tree species differ among the taxonomic groups studied. Canopy cover was the main structural indicator and affected other structural variables such as cover of lower vegetation layers. Other structural indicators included deadwood and distances to forest edge and to broadleaved woodland. Functional indicators included stand age, site environmental characteristics and management practices. Compositional indicators were limited to more easily identifiable plant and bird species. Our results suggest that the biodiversity of any one of the species groups we surveyed cannot act as a surrogate for all of the other species groups. However, certain subgroups, such as forest bryophytes and saproxylic hoverflies, may be able to act as surrogates for each other. The indicators we have identified should be used together to identify stands of potentially high biodiversity or to evaluate the biodiversity effects of silvicultural management practices. They are readily assessed by non-specialists, ecologically meaningful and applicable over a broad area with similar climate conditions and silvicultural systems. The approach we have used to develop biodiversity indicators, including stand structural types, is widely relevant and can enhance sustainable forest management of plantations.     

Increase of biodiversity in homogeneous Scots pine stands by an ecologically diversified management

Three important parameters of biodiversity in first generation Scots pine (Pinus sylvestris) forests on sandy soils have been evaluated: herbal layer diversity, natural regeneration and stand structure. The study took place in the Belgian Campine region, where the original oak–birch forest, degraded to heathlands in the course of time, were finally replaced by monocultures of Scots pine. These first generation pine forests are characterized by a low biodiversity. In maturing stands of this type, however, a spontaneous increase of biodiversity is noticed. Herbal species richness is very limited in all age classes. Different natural regeneration patterns are found. Referring to stand structure, the lengthening of the rotation favours the ingrowth of several hardwood species. As a consequence, the homogenous Scots pine stands are gradually and spontaneously transformed into heterogeneous mixed stands, featuring a noticeable increase in biodiversity. Selected human interventions may further increase biodiversity. The fundamental management principles are discussed: avoidance of major disturbances, lengthening of the rotation period, use of native tree species and natural regeneration, protection of microbiotopes and permanent monitoring.     

Detection of haplotypic variation and natural hybridization in halepensis-complex pine species using chloroplast simple sequence repeat (SSR) markers

In this investigation, nine chloroplast, paternally inherited simple-sequence repeat (cpSSR) markers were used to describe genetic variation of three closely related species belonging to the halepensis complex ( Pinus halepensis Ait., P. brutia Mill. and P. eldarica Medwed.). Both the infinite allele model (IAM) and stepwise-mutation model (SMM) have been applied to the analysis of the genetic structure of natural populations and the geographical distribution of haplotypic variation. SMM-based estimators performed better than IAM-based estimators for large values of within-population diversity and divergence between population pairs. Overall, large haplotypic variation and high genetic divergence were detected for both P. halepensis and P. brutia . The genetic structures of the three species are discussed with consideration to the evolutionary and ecological characteristics of these species. Three highly informative markers showing size variants distinguishing P. halepensis from the other two species were used to provide more information on the occurrence of natural hybridization in a Turkish sympatric population of P. halepensis and P. brutia . Strong evidence of introgression of ' halepensis ' chloroplast haplotypes into P. brutia seeds (but not vice versa) was detected. According to previous evidence from controlled crossings, matings between the above species seem to be successful only when P. halepensis is the pollen donor and P. brutia is the female parent (but not reciprocally). The existence of unidirectional gene flow in sympatric populations confirms previous evidence about partial reproductive barriers between P. halepensis and P. brutia . Implications of the above evidence for the evolutionary history of these species are discussed.     

Breeding performance and longevity of Tomicus destruens on Mediterranean and continental pine species

The pine shoot beetle Tomicus destruens (Wollaston) (Coleoptera: Curculionidae: Scolytinae) is one of the main pests of Mediterranean forests, where it is oligophagous on Mediterranean pines. However, possible global warming may make the insect move to higher latitudes and altitudes, allowing it to attack new pine species. In this respect, the aim of the present article was to assess both the acceptance and performance of T. destruens offered host and non‐host pine species. A no‐choice breeding experiment was set up under laboratory conditions, using logs of three Mediterranean (Pinus pinea L., Pinus pinaster Miller, and Pinus halepensis Aiton) and two continental (Pinus nigra Arnold and Pinus sylvestris L.) pine species. Log debarking at the end of adult emergence assessed parent fecundity, egg, and larval mortality. The quality of callow adults emerging from each tested pine was evaluated on the basis of their longevity on a semiartificial diet. Tomicus destruens colonised all tested pine species, but did not reproduce in Scots pine, taking about 79 days to complete development with no differences among pines tested. The best breeding performance, evaluated as female fecundity and adult production, was observed in P. halepensis, and the lowest in P. pinaster. On average, adults emerging from P. pinea survived longer (83 days) than from other pines, and adult longevity was the lowest in males emerging from P. nigra. Austrian pine, which under natural conditions is usually not a host of T. destruens, allowed insect development and adult production similar to P. pinea and P. pinaster.     

Phenotyping tree resistance to a bark‐chewing insect,the pine weevil Hylobius abietis

Breeding for resistance to forest pests and pathogens is emerging as a promising tool for minimising the impact of the increasing biotic threats that our forests are experiencing as a consequence of global change. Efficient phenotyping protocols of resistance are urgently needed. Here we present the results of two experiments aimed to determine whether the variation in resistance to the pine weevil Hylobius abietis, a harmful pest of European conifers, can be inferred by nondestructive bioassays using excised plant material collected in forest genetic trials. Weevil damage and amount of nonvolatile resin induced by weevil feeding were assessed in young trees and in branches of adult trees using several phenotyping procedures (bioassays using either living trees, excised plant material and cut stem twigs) on four pine species (Pinus pinaster, P. radiata, P. sylvestris and P. pinea). Half of the plants were previously induced with methyl jasmonate (MJ), a treatment that is known to affect resistance to the pine weevil. In Experiment 1, living and excised plants showed parallel results: MJ treatment significantly reduced weevil damage, and saplings responded to weevil damage locally increasing the nonvolatile resin (NVR) in the stems proportionally to the damage suffered. This response was, however, slightly lower in excised than in living saplings. On the contrary, patterns of weevil feeding on stem twigs completely departed from those observed in living and excised seedlings. Moreover, cut stem twigs were unable to respond to weevil feeding increasing NVR according to the weevil damage. In Experiment 2, assessment of weevil damage on excised branches explained around 50% of variation in damage on living branches. This relationship became much more pronounced (R² = 0.81) when explored at the mean treatment level; branch manipulation did not alter the patterns of variation in resistance across pine species or MJ treatments. Irrespective of the assessment procedure, MJ consistently decreased weevil damage in all pine species, with larger reduction in weevil damage in stone and maritime pine than in radiata and Scots pine. Radiata pine was the most resistant while Scots pine was the most susceptible to the pine weevil. Overall, results suggest that using excised plant material is an operative alternative for phenotyping weevil resistance whenever care is taken to maintain the functionality of the excised plant material. This will allow taking advantage of multiple available conifer genetic trials to deepen the ecological genetics of resistance to the pine weevil and to screen for resistance without compromising the long‐term utility of those genetic trials.     

Testing indicators of biodiversity for plantation forests

In many parts of the world, plantations make up a considerable proportion of the total forest area. In such regions, the identification of high biodiversity value stands and of management practices to enhance biodiversity is essential if the goals of Sustainable Forest Management are to be achieved. Since complete biodiversity assessments are rarely possible, efforts have been increasingly focussed on the use of indicators. Of particular interest are indicators applicable to individual stands that require no specialist taxonomic or technical knowledge to assess. Candidate biodiversity indicators had been identified in a previous study using data from Irish Sitka spruce (Picea sitchensis) and ash (Fraxinus excelsior) plantations but had yet to be tested on independent data. In the present study, the provisional indicators for vascular plant, bryophyte, spider and bird diversity were tested on data from Irish Scots pine (Pinus sylvestris), oak (Quercus petraea/Quercus robur), Sitka spruce and lodgepole pine (Pinus contorta) plantations. Conifer canopy cover was confirmed as an important biodiversity indicator, due to its influence on below-canopy microclimatic and structural conditions. Bryophyte species richness was higher in relatively high canopy cover plantations on poorly drained soils, while bird species richness was higher in more open plantations with high shrub cover. Coarse woody debris was an important substrate for forest-associated bryophytes, with higher species richness at higher volumes of deadwood. Both proximity to old woodland and stand age were confirmed as positive indicators for forest-associated vascular plants. This is related to dispersal limitation in these species, with nearby woodlands acting as important seed sources and colonisation increasing with time. Stand age was also confirmed as a positive indicator for forest-associated spiders and is related to the development of suitable habitat as the plantation matures. All of the confirmed indicators can be assessed without need for specialist knowledge, are ecologically meaningful and applicable to a range of forests managed under a clearfelling system. They can be used to assess the potential value of stands for the taxonomic groups to which they apply, as well as giving insights into management practices to enhance diversity in these groups.     

皖东松树纯林与复层混交林比较研究

通过对皖东地区松树纯林和零星分布的复层林的调查,比较了单纯林和复层林的材积生长以及林地土壤理化性质的改善情况,研究了林内的光环境和庇荫下的林木的生理生态特性,认为建立充分发挥森林多种效益的人工复层林施业体系是该地区林业经营的方向．     

Monitoring the European pine sawfly with pheromone traps in maturing Scots pine stands

Abstract

• 1 During 1989–93, field studies were conducted in Finland to develop a method based on pheromone traps to monitor and forecast population levels of the European pine sawfly (Neodiprion sertifer Geoffr.) and tree defoliation.
• 2 Three traps per site were baited with 100 µg of the N. sertifer sex pheromone, the acetate ester of (2S,3S,7S)‐3,7‐dimethyl‐2‐pentadecanol (diprionol), in maturing pine stands in southern and central Finland. In addition, three different dosages (1, 10 and 100 µg) of the pheromone were tested in 1991–92.
• 3 The highest number of males was observed in traps baited with the highest dose. On average, there was a 10‐fold increase in trap catch between lure doses.
• 4 Density of overwintering eggs was used to evaluate the effectiveness of pheromone traps in predicting sawfly populations. The proportion of healthy overwintering eggs was determined each year. A model based on the number of current shoots on sample trees, diameter at breast height and tree height was formulated to estimate eggs per hectare.
• 5 Linear regression analysis produced high coefficients of determination between number of males in traps and density of total eggs in the subsequent generation, when populations were at peak densities. The relationships were not significant for low population densities. The results indicate a risk of moderate defoliation when the seasonal trap catch is 800–1000 males per trap or higher.

     

可持续经营框架下阔叶红松林区生物多样性间接评价体系的研究

森林生物多样性的保护和持续利用是森林可持续经营的重要内容,如何快速有效地评价生物多样性是当前森林经营实践中面临的重要问题。本文以可持续发展为指导思想,针对阔叶红松林区森林可持续经营中的生物多样性保护问题,提出了一套生物多样性间接评价的体系和评价方法。生物多样性间接评价的基本原理是以物种与生境的关系、森林自然干扰状况、物种间的相互关系和对特殊生境及敏感物种的考虑等为基础的。依据阔叶红松林区的干扰状况、林分一般状况、立木层、灌木层、草本层、附生植物和藤本植物等的特点,采用重复累加的方法,制定了阔叶红松林区林分生物多样性间接评价的打分表。在一个森林经营单位(林业局或林场)进行生物多样性的保护时,首先应根据不同森林类型对干扰的适应和抵抗力大小确定对各类森林优先保护的次序,然后再在各类森林的不同小班中进行生物多样性间接评价打分表的填写,最后根据不同小班生物多样性得分的多少确定其保护的等级或先后次序。生物多样性间接评价调查可以结合森林经理调查来进行。     

Native biodiversity collapse in the eastern Mediterranean

Global warming causes the poleward shift of the trailing edges of marine ectotherm species distributions. In the semi-enclosed Mediterranean Sea, continental masses and oceanographic barriers do not allow natural connectivity with thermophilic species pools: as trailing edges retreat, a net diversity loss occurs. We quantify this loss on the Israeli shelf, among the warmest areas in the Mediterranean, by comparing current native molluscan richness with the historical one obtained from surficial death assemblages. We recorded only 12% and 5% of historically present native species on shallow subtidal soft and hard substrates, respectively. This is the largest climate-driven regional-scale diversity loss in the oceans documented to date. By contrast, assemblages in the intertidal, more tolerant to climatic extremes, and in the cooler mesophotic zone show approximately 50% of the historical native richness. Importantly, approximately 60% of the recorded shallow subtidal native species do not reach reproductive size, making the shallow shelf a demographic sink. We predict that, as climate warms, this native biodiversity collapse will intensify and expand geographically, counteracted only by Indo-Pacific species entering from the Suez Canal. These assemblages, shaped by climate warming and biological invasions, give rise to a ‘novel ecosystem’ whose restoration to historical baselines is not achievable.     

广西国有林场森林生物多样性变化评价

采用压力—状态—响应评价法对 1 990～ 2 0 0 1年广西国有林场森林生物多样性进行了研究 ,发现林场森林生物多样性十多年来呈下降趋势。导致森林生物多样性减少的主要根源是林场人口急剧增长和不当的森林经营方式。提出了控制人口增长、转变森林经营方式以遏制林场森林生物多样性减少、保护森林生物多样性的对策     

Integrating needs of the local community to conserve forest biodiversity in the state of Kelantan

Kelantan State, claimed to be one of the poorest states in Malaysia, has forest lands, nature reserves and other protected natural areas which are under increasing threat from a variety of human activities. At the same time, the State government lacks financial resources and skilled manpower to manage the protected forest lands adequately. The present strategies to manage protected forest areas are inadequate to overcome these constraints. Alternative strategies are needed to conserve Kelantan's forest biodiversity. Furthermore, conservation efforts will not be effective without the active cooperation and participation of people living in and near the forest areas. To achieve this, it is essential that the people share the benefits and responsibilities of forest resource management with the state government.A proposal to involve the local people in an integrated action plan is discussed in this paper. It aims to find options of protecting forest land encroachment in the State with an ultimate goal of increasing the capacity of the poor to carry out activities on a sustained basis. It is hoped that the proposed project will help the State government to improve economic status as well as environmental awareness and reduced dependence on forest lands.Much of the forest lands in Kelantan are threatened by encroachment from the people who live around the forest areas. This encroachment is not only the result of poverty and shortage of land, but is also due to the unclear forest boundaries. People also do not understand the significance of forest biodiversity. It is important therefore that the local people are encouraged not to encroach into the forest areas. There has to be support from the top in order to sustain integration efforts. Both the State and the central government agencies must be a part of the planning and implementation process. The challenge becomes one of integrating the needs of the local people with development priorities of the government. In practical terms, this paper hopes to arrive at a workable methodology rather than be a purely scientific exercise which can serve as a model to the other states experiencing similar problems.Presented at the Asean Seminar on Management and Conservation of Biodiversity, 29 November–1 December 1993, Kuala Lumpur.     

Patterns of saproxylic beetle succession in loblolly pine

• 1 Patterns of insect succession in dead wood remain unclear, particularly beyond the first several years of decay. In the present study, saproxylic beetles were sampled from loblolly pine (Pinus taeda L.) logs aged between 1 month and 9 years old using both emergence traps attached to logs in the field and rearing bags in the laboratory.
• 2 Species richness peaked within the first year as a result of a diverse assemblage of bark beetles, wood‐borers and predators associated with young logs. After the phloem phase, there were no significant differences in species richness among decay classes.
• 3 Beetle communities differed significantly among decay classes, with 25 and seven species being significantly associated with young and old logs, respectively.

     

中国海洋生物多样性的保护和管理对策

本文全面介绍了中国海洋物种多样性的现状,并分析其受到的人类影响和主要威胁。详细阐述了国家海洋局及其下属部门在海洋生物多样性保护管理中制定的有关政策、法规及行动计划,以及海洋生物多样性的科学调查研究及海洋生态环境监测体系建设,海洋自然保护区的建设与管理,海洋生物多样性可持续利用等方面的工作和进展。同时,在生物多样性管理现状的基础上,提出了包括预警系统与事故处理能力建设、将生物多样性保护管理纳入区域经济社会发展计划、建设生物多样性管理机构及法规之间的协调机制以及基于生态系统的生物多样性管理和公众参与等若干针对性的管理对策。