Producing wood at least cost to biodiversity: integrating Triad and sharing–sparing approaches to inform forest landscape management

Forest loss and degradation are the greatest threats to biodiversity worldwide. Rising global wood demand threatens further damage to remaining native forests. Contrasting solutions across a continuum of options have been proposed, yet which of these offers most promise remains unresolved. Expansion of high-yielding tree plantations could free up forest land for conservation provided this is implemented in tandem with stronger policies for conserving native forests. Because plantations and other intensively managed forests often support far less biodiversity than native forests, a second approach argues for widespread adoption of extensive management, or ‘ecological forestry’, which better simulates natural forest structure and disturbance regimes – albeit with compromised wood yields and hence a need to harvest over a larger area. A third, hybrid suggestion involves ‘Triad’ zoning where the landscape is divided into three sorts of management (reserve, ecological/extensive management, and intensive plantation). Progress towards resolving which of these approaches holds the most promise has been hampered by the absence of a conceptual framework and of sufficient empirical data formally to identify the most appropriate landscape-scale proportions of reserves, extensive, and intensive management to minimize biodiversity impacts while meeting a given level of demand for wood. In this review, we argue that this central challenge for sustainable forestry is analogous to that facing food-production systems, and that the land sharing–sparing framework devised to establish which approach to farming could meet food demand at least cost to wild species can be readily adapted to assess contrasting forest management regimes. We develop this argument in four ways: (i) we set out the relevance of the sharing–sparing framework for forestry and explore the degree to which concepts from agriculture can translate to a forest management context; (ii) we make design recommendations for empirical research on sustainable forestry to enable application of the sharing–sparing framework; (iii) we present overarching hypotheses which such studies could test; and (iv) we discuss potential pitfalls and opportunities in conceptualizing landscape management through a sharing–sparing lens. The framework we propose will enable forest managers worldwide to assess trade-offs directly between conservation and wood production and to determine the mix of management approaches that best balances these (and other) competing objectives. The results will inform ecologically sustainable forest policy and management, reduce risks of local and global extinctions from forestry, and potentially improve a valuable sector's social license to operate.     

林业活动和森林片断化对甲虫多样性的影响及保护对策

森林片断化是造成生物多样性丧失的主要原因之一,而林业活动是导致森林片断化的重要因素,同时也在森林恢复中起重要作用。本文从小尺度、局域尺度以及生物地理尺度（大尺度）3个生态尺度分析林业活动和森林片断化对甲虫多样性的影响。在小尺度下,林业活动能够通过改变森林生境或微生境的类型和特性而影响甲虫物种分布。在局域尺度下,林业活动（尤其是森林砍伐）往往能提高许多甲虫类群（如步甲）的物种丰富度（α多样性）,这主要与来自周围环境物种扩散以及保留了若干耐受新环境能力较强的森林物种有关;然而,对森林生境依赖性很强的特有种受到了森林片断化的负面影响,面临局域种群灭绝的危险。在生物地理尺度下,林业活动（伐木或森林恢复）使森林生境单一化、异质性降低,从而导致对森林生境变化敏感的物种种群数量降低甚至灭绝。基于以上结果,可以归纳出3个基本原则用于指导林业管理,既能保证林业经济收益,又能维持森林生物多样性。首先,保留大面积的原始森林作为特有种的栖息环境基地,为这些物种在将来森林恢复后重新定居提供资源;其次,由于保护区内原始森林面积有限,且所代表的生境类型有限,所以发展依据自然干扰模式的新伐木方法十分必要;最后,依据自然规律（如火灾）进行森林恢复和天然演替,避免森林的单一化,丰富森林生境类型。     

Plantation forests,climate change and biodiversity

Nearly 4 % of the world’s forests are plantations, established to provide a variety of ecosystem services, principally timber and other wood products. In addition to such services, plantation forests provide direct and indirect benefits to biodiversity via the provision of forest habitat for a wide range of species, and by reducing negative impacts on natural forests by offsetting the need to extract resources. There is compelling evidence that climate change is directly affecting biodiversity in forests throughout the world. These impacts occur as a result of changes in temperature, rainfall, storm frequency and magnitude, fire frequency, and the frequency and magnitude of pest and disease outbreaks. However, in plantation forests it is not only the direct effects of climate change that will impact on biodiversity. Climate change will have strong indirect effects on biodiversity in plantation forests via changes in forest management actions that have been proposed to mitigate the effects of climate change on the productive capacity of plantations. These include changes in species selection (including use of species mixtures), rotation length, thinning, pruning, extraction of bioenergy feedstocks, and large scale climate change driven afforestation, reforestation, and, potentially deforestation. By bringing together the potential direct and indirect impacts of climate change we conclude that in the short to medium term changes in plantation management designed to mitigate or adapt to climate change could have a significantly greater impact on biodiversity in such plantation forests than the direct effects of climate change. Although this hypothesis remains to be formally tested, forest managers worldwide are already considering new approaches to plantation forestry in an effort to create forests that are more resilient to the effects of changing climatic conditions. Such change presents significant risks to existing biodiversity values in plantation forests, however it also provides new opportunities to improve biodiversity values within existing and new plantation forests. We conclude by suggesting future options, such as functional zoning and species mixtures applied at either the stand level or as fine-scale mosaics of single-species stands as options to improve biodiversity whilst increasing resilience to climate change.     

Plantation forests and biodiversity: oxymoron or opportunity?

Losses of natural and semi-natural forests, mostly to agriculture, are a significant concern for biodiversity. Against this trend, the area of intensively managed plantation forests increases, and there is much debate about the implications for biodiversity. We provide a comprehensive review of the function of plantation forests as habitat compared with other land cover, examine the effects on biodiversity at the landscape scale, and synthesise context-specific effects of plantation forestry on biodiversity. Natural forests are usually more suitable as habitat for a wider range of native forest species than plantation forests but there is abundant evidence that plantation forests can provide valuable habitat, even for some threatened and endangered species, and may contribute to the conservation of biodiversity by various mechanisms. In landscapes where forest is the natural land cover, plantation forests may represent a low-contrast matrix, and afforestation of agricultural land can assist conservation by providing complementary forest habitat, buffering edge effects, and increasing connectivity. In contrast, conversion of natural forests and afforestation of natural non-forest land is detrimental. However, regional deforestation pressure for agricultural development may render plantation forestry a ‘lesser evil’ if forest managers protect indigenous vegetation remnants. We provide numerous context-specific examples and case studies to assist impact assessments of plantation forestry, and we offer a range of management recommendations. This paper also serves as an introduction and background paper to this special issue on the effects of plantation forests on biodiversity.

Non-native plantation forests as alternative habitat for native forest beetles in a heavily modified landscape

The once extensive native forests of New Zealand’s central North Island are heavily fragmented, and the scattered remnants are now surrounded by a matrix of exotic pastoral grasslands and Pinus radiata plantation forests. The importance of these exotic habitats for native biodiversity is poorly understood. This study examines the utilisation of exotic plantation forests by native beetles in a heavily modified landscape. The diversity of selected beetle taxa was compared at multiple distances across edge gradients between each of the six possible combinations of adjacent pastoral, plantation, clearfell and native forest land-use types. Estimated species richness (Michaelis–Menten) was greater in production habitats than native forest; however this was largely due to the absence of exotic species in native forest. Beetle relative abundance was highest in clearfell-harvested areas, mainly due to colonisation by open-habitat, disturbance-adapted species. More importantly, though, of all the non-native habitats sampled, beetle species composition in mature P. radiata was most similar to native forest. Understanding the influence of key environmental factors and stand level management is important for enhancing biodiversity values within the landscape. Native habitat proximity was the most significant environmental correlate of beetle community composition, highlighting the importance of retaining native remnants within plantation landscapes. The proportion of exotic beetles was consistently low in mature plantation stands, however it increased in pasture sites at increasing distances from native forest. These results suggest that exotic plantation forests may provide important alternative habitat for native forest beetles in landscapes with a low proportion of native forest cover.     

Standards for biodiversity: a proposal based on biodiversity standards for forest plantations

The 1992 Convention on Biological Diversity has not only focused attention on the concept of biodiversity it has also set expectations that the signatory nations will establish objectives. It is suggested here that the use of biodiversity standards could have a useful role in quantifying these objectives. The use of biodiversity standards is explored in connection with the levels of biodiversity In plantation forests. Forest plantations have been used for the basis of this investigation because such plantations could be used as large-scale experiments in which the use of standards, and the ecological monitoring of these standards, could be researched. The impact of intensive forestry practices on wildlife has often been the cause of concern and indeed controversy. Recently there has been a move towards the development of multipurpose forest plantations where management for recreation and wildlife takes place alongside management for timber. Some forest authorities are actively looking at ways of restoring levels of biodiversity in plantation forests. We suggest that if levels of biodiversity are to be restored, then forest managers must have something to aim for; that is, there must be a standard. The adoption of standards could provide a means whereby forest managers can meet biodiversity objectives. Standards may also enable managers to determine the effectiveness of those management practices which are intended to increase levels of biodiversity. We suggest a conceptual plan which combines a monitoring procedure with biodiversity objectives.     

森林管理在全球CO2减排中的作用

综述了各种森林管理措施在全球CO₂减排中的作用.这些管理措施主要包括减少森林砍伐速度,增加森林覆盖面积,加强对现存森林的肥料、火灾及病虫害管理,以薪材替代化石燃料等.同时探讨了中国的森林管理存在的优势和不足.目前中国森林生态系统主要是植被碳库,在全球碳循环过程中扮演着“碳汇”的角色,但其“碳汇”功能较小.因此,如何加强对新建人工林的抚育、病虫害和火灾管理,增强中国森林的“碳汇”功能,充分发挥其在CO₂减排中的作用,是我们面临的重要工作     

Indigenous community forest management of Jinuo people's swidden agroecosystems in southwest China

According to their traditional classification, the Jinuo's community forests consisted of watershed forest, auspicious forest, sacred forest, shellac forest, village/clan boundary forest, fire protection forest, burial forest and swidden fallow forest. Every type of forest was managed through traditional regulations. The village or clan headman and his assistant were the representatives to implement the traditional management system. Because it was popular with local villagers and there was strict punishment of offenders, the management system was effective. In recent years, the constantly changing forest management policies has not helped either to preserve biodiversity, or to develop forestry. Instead, forest ecosystems have been destroyed. After studying the community forests in the Jinuo community, the authors strongly recommend that the indigenous forest management system be strengthened. Modern forestry policy itself cannot implement sustainable, productive forestry and conserve biodiversity unless it is combined with the indigenous management system of the community.     

Stand structure and natural regeneration of degraded forestland in the northern mountainous region of Vietnam

Vietnam experienced significant alterations of forest environments during the last half of the twentieth century, and reforestation efforts have increased since the 1990s. This study developed comparisons of naturally regenerated and plantation forestlands in northern Vietnam in order to gain a better understanding of reforestation options for the dual objectives of biodiversity and commercial tree production. Stand structure of secondary natural forest after logging and shifting cultivation were investigated at two study sites (Hoa Binh Province and Phu Tho Province). Natural regeneration of seedlings between the secondary natural forests and nearby mixed species plantations were measured and compared. The dominant tree species consisted of Aporosa villosa, Ficus racemosa, Machilus bonii and Vernicia montan at the Hoa Binh site and Cinnamomum parthenoxylum, Ormosia balabsae and Lithocarpus gigantophyllus at the Phu Tho site, which are mostly pioneer species. The secondary natural forests had higher abundance and diversity indices of seedlings than the mixed species plantations. Soil fertility of the secondary natural forests was better than that of the mixed species plantations (P < 0.05). An important finding is that, for the study sites examined, secondary natural forest resulted in more diverse and better-stocked forests than plantation forestry, implying that in areas where reforestation is undertaken the silvicultural potential of natural regeneration should not be underestimated.     

Comparing forest structure and biodiversity on private and public land: secondary tropical dry forests in Costa Rica

Secondary forests constitute a substantial proportion of tropical forestlands. These forests occur on both public and private lands and different underlying environmental variables and management regimes may affect post‐abandonment successional processes and resultant forest structure and biodiversity. We examined whether differences in ownership led to differences in forest structure, tree diversity, and tree species composition across a gradient of soil fertility and forest age. We collected soil samples and surveyed all trees in 82 public and 66 private 0.1‐ha forest plots arrayed across forest age and soil gradients in Guanacaste, Costa Rica. We found that soil fertility appeared to drive the spatial structure of public vs. private ownership; public conservation lands appeared to be non‐randomly located on areas of lower soil fertility. On private lands, areas of crops/pasture appeared to be non‐randomly located on higher soil fertility areas while forests occupied areas of lower soil fertility. We found that forest structure and tree species diversity did not differ significantly between public and private ownership. However, public and private forests differed in tree species composition: 11 percent were more prevalent in public forest and 7 percent were more prevalent in private forest. Swietenia macrophylla, Cedrela odorata, and Astronium graveolens were more prevalent in public forests likely because public forests provide stronger protection for these highly prized timber species. Guazuma ulmifolia was the most abundant tree in private forests likely because this species is widely consumed and dispersed by cattle. Furthermore, some compositional differences appear to result from soil fertility differences due to non‐random placement of public and private land holdings with respect to soil fertility. Land ownership creates a distinctive species composition signature that is likely the result of differences in soil fertility and management between the ownership types. Both biophysical and social variables should be considered to advance understanding of tropical secondary forest structure and biodiversity.     

Effects of intensified forestry on the landscape-scale extinction risk of dead wood dependent species

In the future, a significant proportion of Northern forests may become intensively managed through the planting of monospecific stands of native or introduced trees, and the use of multiple silvicultural treatments such as forest fertilization. Such an intensification of management in selected parts of the landscape is suggested by different zoning models, for example the Triad approach, which is under evaluation in some regions of North America. In this study, based on Fennoscandian conditions, we predicted landscape-scale extinction risks of five hypothetical model insect species dependent on fresh dead wood from Norway spruce (Picea abies), by simulating colonizations and local extinctions in forest stands. Intensified forestry applied to 50% of the spruce stands led to strongly increased extinction risks of all species during the following 150 years. For one species—the sun-exposure specialist—there were strong effects already after 50 years. The negative effects of intensive plantation forestry could be compensated for by taking greater biodiversity conservation measures in other managed forests or by setting aside more forests. This is consistent with the Triad model, which is according to our analyzes an effective way to decrease extinction risks, especially for the short-dispersing species and the species associated with closed forest. A zoning of forest land into intensive forestry, conventional forestry, and set asides may be better at combining increased timber production and maintenance of biodiversity in comparison to landscapes where all production forests are managed in the same way.     

Modelling land use changes for landscape connectivity: The role of plantation forestry and highways

Landscape connectivity is a key aspect for the maintenance of biodiversity and ecosystem viability. Nowadays, the competition between economic development and nature conservation is intense. In most territories natural vegetation is being replaced by exotic tree plantations, which have a better performance in terms of timber productivity but often, a lower ecological value. We evaluated potential natural forest connectivity improvement in the Cantabria region (Northern Spain) through two main actions: protection of environmentally valuable forest areas, and reforestation with indigenous species of those patches of exotic plantation trees with a particularly important role for the connectivity of the forest network. We established a variety of scenarios to calculate least cost paths, considering the presence or absence of plantation forestry and highways to examine connectivity. Then, we applied two habitat availability indices (integral index of connectivity and probability of connectivity) attending to different dispersal distances. Our analyses show a great potential for improving connectivity using plantation forests in the natural forest network, and a dramatic impact of the highway in the north–south connectivity of the study area. Based on these results, we identified those patches of plantation forest and natural forest that are more important for the maintenance of overall landscape connectivity, and propose their protection or conversion through reforestation. The final proposed network constitutes a larger and better connected natural forested landscape than the existing one.     

Co‐benefits of biodiversity and carbon sequestration from regenerating secondary forests in the Philippine uplands: implications for forest landscape restoration

Shifting cultivation is a widespread practice in tropical forested areas that policy makers often regard as the major cause of forest degradation. Secondary fallow forests regrowing after shifting cultivation are generally not viewed as suitable for biodiversity conservation and carbon retention. Drawing upon our research in the Philippines and other relevant case studies, we compared the biodiversity and carbon sequestration in recovering secondary forests after shifting cultivation to other land uses that commonly follow shifting cultivation. Regenerating secondary forests had higher biodiversity than fast growing timber plantations and other restoration options available in the area. Some old plantations, however, provided carbon benefits comparable the old growth forest, although their biodiversity was less than that of the regenerating forests. Our study demonstrates that secondary forests regrowing after shifting cultivation have a high potential for biodiversity and carbon sequestration co‐benefits, representing an effective strategy for forest management and restoration in countries where they are common and where the forest is an integral part of rural people's livelihoods. We discuss the issues and potential mechanisms through which such dynamic land use can be incorporated into development projects that are currently financing the sustainable management, conservation, and restoration of tropical forests.     

Assessment and management of old-growth forests in south eastern Australia

Abstract

Old-growth forests in south eastern Australia are important for biodiversity conservation, recreation, carbon storage, social values and, to a declining extent, for timber production. Developing a comprehensive definition of old-growth forest that can apply across all Australian vegetation types has been challenging. Old growth can be viewed from ecological and social perspectives. For policy and management purposes old growth has been defined as a growth stage in forest development, incorporating ecological maturity and lack of evidence of past disturbance. Classification and assessment of old growth has largely been restricted to those areas covered by regional forest agreements (RFAs) between different states and the Federal Government. Old growth can be impacted by wildfire, timber harvesting, insect pests, diseases and other disturbances. Climate change will also present challenges for the future management of old-growth forests. There is increasing scientific understanding of the relationships between species, forest growth stage and old-growth forest attributes. To meet biodiversity conservation objectives, the management focus is shifting from assessing and protecting old-growth forests, to providing for forests across the landscape with old-growth attributes. This approach may be at odds with other conceptions of old growth based on notions of undisturbed systems free of human influence.     

Benchmarks and predictors of coarse woody debris in native forests of eastern Australia

Fallen coarse woody debris (CWD) is critical to forest biodiversity and function. Few studies model factors that influence CWD availability, although such investigations are critically needed to inform sustainable forest management. We assess benchmark levels of CWD in unharvested native forests and those harvested for timber, across a range of forests in north‐east New South Wales, Australia. We found timber‐harvesting was the dominant driver of CWD, with almost double the count (pieces ha^?1) and volume (m³ ha^?1) of total CWD in selectively harvested than unharvested sites. This pattern was consistent across wet and dry forest types. Harvested sites had greater counts of hollow‐bearing logs, and greater volumes of small and medium‐sized CWD (15–50 cm diameter) than unharvested sites. There was no effect of harvesting on the volume of large CWD (>51 cm diameter). Total volumes of CWD (>15 cm diameter) varied from 114 to 166 m³ ha^?1. We found few differences in CWD counts and volumes between forest types, with grassy woodlands and forests containing less CWD than other dry and shrubby forest types, reflecting lower potential input rates. The CWD levels recorded here are similar to those recorded in dry and wet sclerophyll forests elsewhere in Australia and are typical of global estimates for ‘old growth’ forests. Using general linear models we captured up to 57% of the variation in CWD across sites, and found that timber harvesting, topography and the numbers of standing hollow‐bearing and dead trees were significant predictors of CWD. Values for unharvested forest provide a benchmark that could be used to inform retention guidelines for CWD in managed forests in this region. Further assessment of the effect of repeat timber harvesting is needed to fully understand its impact on CWD dynamics, especially if forest residues resulting from timber harvesting are removed from native forests for bioenergy production.     

Recovery of species diversity and composition of braconid parasitic wasps after reforestation of degraded grasslands in lowland East Kalimantan

Human-induced disturbances and wildfires can transform areas of tropical rainforest into Imperata-dominated grassland, but it may be possible that recovery of biodiversity is facilitated by reforestation with fast-growing trees. We compared the assemblages of braconid wasps as parasitoids of taxonomically diverse groups of insects among Imperata grasslands, young and mature plantations of Acacia mangium, young secondary forests after wildfires, and old secondary forests in the lowland of East Kalimantan. The abundance and species richness of braconids, which had declined in Imperata grasslands, somewhat increased in Acacia plantations, and also the species composition of braconids in Acacia plantations was transitional between Imperata grasslands and old secondary forests. Parasitoids of detritivores and wood borers increased markedly after plantation, while those of herbivores showed a distinct turnover of species all over the range from grasslands to old secondary forests. The plantation of A. mangium had most likely facilitated the recovery of the diversity of host forest and their parasitoids, but the recovery was just at the rudimentary stage even in mature plantations. Monitoring of parasitic wasps would be useful to test the continuous recovery of forest biodiversity in plantation stands.     

The value of the trackway system within a lowland plantation forest for ground-active spiders

European forest management guidelines include conservation and enhancement of biodiversity. Within plantation forestry, trackways provide contiguous permanent open-habitat with potential to enhance biodiversity. We examined the ground-active spider assemblage in the trackway network of Thetford Forest, Eastern England, the largest lowland conifer forest in the UK, created by afforestation of heathland and farmland. Results are relevant to other forests in heath regions across Europe. We used pitfall trapping to sample the spider assemblage of trackways within thicket-aged stands (n = 17), mature stands (n = 13) and heathland reference sites (n = 9). A total of 9,314 individuals of 71 species were recorded. Spider assemblages of the trackway network were distinct from those of the heathland reference sites; however, trackways were found to support specialist species associated with grass-heath habitats, including nationally scarce species. Richness of grass-heath species was similar for trackways in thicket-aged forest and heathland reference sites, although the abundance of individuals was three times greater in the reference sites. Trackways in mature stands had lower grass-heath species richness and abundance than both thicket trackways and heath reference sites. Wide trackways within thicket stands contained greater richness and abundance of specialist xeric species than narrower trackways. However, fewer xeric individuals were found in trackways compared to heathland reference sites. Either inferior habitat quality in trackways or poor dispersal ability of specialist xeric species may largely restrict these to relict areas of heathland. Targeted widening of trackways to allow permanent unshaded habitat and creating early successional stages by mechanical disturbance regimes could improve trackway suitability for specialist species, helping to restore connectivity networks for grass-heath biodiversity.     

The persistence and conservation of Borneo’s mammals in lowland rain forests managed for timber: observations, overviews and opportunities

Lowland rainforests on Borneo are being degraded and lost at an alarming rate. Studies on mammals report species responding in various ways to habitat changes that occur in commercial forestry concessions. Here we draw together information on the relationship between the ecological, evolutionary, and biogeographic characteristics of selected Bornean non-volant mammals, and their response to timber harvesting and related impacts. Only a minority of species show markedly reduced densities after timber harvesting. Nonetheless there are many grounds for concern as various processes can, and often do, reduce the viability of wildlife populations. Our review of what we know, and of current understanding, helps predict mammalian dynamics and subsequent mammal-induced ecosystem changes in logged forests. We identify groups of mammal species that, although largely unstudied, are unlikely to tolerate the impacts associated with timber harvesting. On a positive note we find and suggest many relatively simple and low-cost ways in which concession management practices might be modified so as to improve the value of managed forests for wildlife conservation. Improving forest management can play a vital role in maintaining the rich biodiversity of Borneo’s tropical rain forests.     

The role of planted forests in the provision of habitat: an Irish perspective

The continued decline of natural forests globally has increased interest in the potential of planted forests to support biodiversity. Here, we examine the potential conservation benefits of plantation forests from an Irish perspective, a country where remaining natural forests are fragmented and degraded, and the majority of the forest area is comprised of non-native Sitka spruce (Picea sitchensis (Bong.) Carr.) and Norway spruce (Picea abies (L.) Karst.) plantations. We examine the true value of Irish plantation forests to native biodiversity, relative to remaining natural forest fragments, and to prior and alternative land use to afforestation. We find that plantation forests provide a suitable surrogate habitat primarily for generalist species, as well as providing habitat for certain species of conservation concern. However, we find that plantation forests provide poor habitat for native forest specialists, and examine potential management strategies which may be employed to improve habitat provision services for this group.     

Developing a forest biodiversity monitoring approach for New Zealand

There is a lack of comprehensive and consistent information to inform policy makers about the status of New Zealand’s forest biodiversity. Three reasons for collecting such information are: assessing the effectiveness of management, reporting on the status of biodiversity under national and international requirements, and improving our knowledge of ecosystem dynamics for designing effective management systems. The challenge is to design monitoring systems that address these multiple needs simultaneously, and at a range of spatial and temporal scales. This article first considers principles for designing enduring monitoring systems based on past experiences, assessing how effectively these principles were implemented in designing New Zealand’s Carbon Monitoring System (CMS), and finally, suggesting future directions for forest biodiversity monitoring in New Zealand. At a national scale we support an unbiased, systematic sample of forests as implemented in several countries (e.g. Austria and the U.S.A.). We consider it best practice to monitor shifts in the fundamental compositional, structural and functional characteristics of ecosystems and use these to derive indicators. We suggest forest biodiversity indicators should include forest area and spatial arrangement, tree mortality and recruitment, exotic weeds, introduced herbivore impacts, and woody debris. Principles discussed in this paper are relevant to biodiversity monitoring in a wider range of ecosystems than forests. Without spatially extensive, robustly designed, biodiversity monitoring systems, New Zealand will remain in a relatively weak position nationally, and internationally, to report on the effectiveness of biodiversity conservation.