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Mature trees scattered throughout agricultural landscapes are critical habitat for some biota and provide a range of ecosystem services. These trees are declining in intensively managed agricultural landscapes globally. We developed a simulation model to predict the rates at which these trees are declining, identified the key variables that can be manipulated to mitigate this decline, and compared alternative management proposals. We used the initial numbers of trees in the stand, the predicted ages of these trees, their rate of growth, the number of recruits established, the frequency of recruitment, and the rate of tree mortality to simulate the dynamics of scattered trees in agricultural landscapes. We applied this simulation model to case studies from Spain, United States, Australia, and Costa Rica. We predicted that mature trees would be lost from these landscapes in 90-180 years under current management. Existing management recommendations for these landscapes - which focus on increasing recruitment - would not reverse this trend. The loss of scattered mature trees was most sensitive to tree mortality, stand age, number of recruits, and frequency of recruitment. We predicted that perpetuating mature trees in agricultural landscapes at or above existing densities requires a strategy that keeps mortality among established trees below around 0.5% per year, recruits new trees at a rate that is higher than the number of existing trees, and recruits new trees at a frequency in years equivalent to around 15% of the maximum life expectancy of trees. Numbers of mature trees in landscapes represented by the case studies will decline before they increase, even if strategies of this type are implemented immediately. This decline will be greater if a management response is delayed.

International audience; Despite increasing efforts to reach sustainability, key global biophysical indicators such as climate change and biodiversity loss continue to deteriorate rather than improve. Ongoing failure to move towards sustainability calls into question the focus of current research and policy. We recommend two strategies for progress. First, sustainability must be conceptualized as a hierarchy of considerations, with the biophysical limits of the Earth setting the ultimate boundaries within which social and economic goals must be achieved. Second, transdisciplinary research programs must confront key normative questions facing modern consumer societies. The humanities should have a key role in such programs. Assisted by these strategies, ambitious targets that realistically reflect the biophysical limits of the life-support system of the Earth must be set and relentlessly worked towards.

The destruction and transformation of ecosystems by humans threatens biodiversity, ecosystem function, and vital ecosystem services. Ecological repair of ecosystems will be a major challenge over the next century and beyond. Restoration efforts to date have frequently been ad hoc, and site or situation specific. Although such small-scale efforts are vitally important, without large-scale visions and coordination, it is unlikely that large functioning ecosystems will ever be constructed by chance through the cumulative effects of small-scale projects. Although the problems of human-induced environmental degradation and the need for a solution are widely recognized, these issues have rarely been addressed on a sufficiently large-scale basis. There are numerous barriers that prevent large-scale ecological restoration projects from being proposed, initiated, or carried through. Common barriers include the "shifting baseline syndrome," the scale and complexity of restoration, the long-term and open-ended nature of restoration, funding challenges, and preemptive constraint of vision. Two potentially useful approaches that could help overcome these barriers are stretch goals and backcasting. Stretch goals are ambitious long-term goals used to inspire creativity and innovation to achieve outcomes that currently seem impossible. Backcasting is a technique where a desired end point is visualized, and then a pathway to that end point is worked out retrospectively. A case study from the Scottish Highlands is used to illustrate how stretch goals and backcasting could facilitate large-scale restoration. The combination of these approaches offers ways to evaluate and shape options for the future of ecosystems, rather than accepting that future ecosystems are victims of past and present political realities. The destruction and transformation of ecosystems by humans threatens biodiversity, ecosystem function, and vital ecosystem services. Ecological repair of ecosystems will be a major challenge over the next century and beyond. Restoration efforts to date have frequently been ad hoc, and site or situation specific. Although such small‐scale efforts are vitally important, without large‐scale visions and coordination, it is unlikely that large functioning ecosystems will ever be constructed by chance through the cumulative effects of small‐scale projects. Although the problems of human‐induced environmental degradation and the need for a solution are widely recognized, these issues have rarely been addressed on a sufficiently large‐scale basis. There are numerous barriers that prevent large‐scale ecological restoration projects from being proposed, initiated, or carried through. Common barriers include the “shifting baseline syndrome,” the scale and complexity of restoration, the long‐term and open‐ended nature of restoration, funding challenges, and preemptive constraint of vision. Two potentially useful approaches that could help overcome these barriers are stretch goals and backcasting. Stretch goals are ambitious long‐term goals used to inspire creativity and innovation to achieve outcomes that currently seem impossible. Backcasting is a technique where a desired end point is visualized, and then a pathway to that end point is worked out retrospectively. A case study from the Scottish Highlands is used to illustrate how stretch goals and backcasting could facilitate large‐scale restoration. The combination of these approaches offers ways to evaluate and shape options for the future of ecosystems, rather than accepting that future ecosystems are victims of past and present political realities.

Biodiversity conservation in forestry and agricultural landscapes is important because (1) reserves alone will not protect biodiversity; (2) commodity production relies on vital services provided by biodiversity; and (3) biodiversity enhances resilience, or a system's capacity to recover from external pressures such as droughts or management mistakes. We suggest ten guiding principles to help maintain biodiversity, ecosystem function, and resilience in production landscapes. Landscapes should include structurally characteristic patches of native vegetation, corridors and stepping stones between them, a structurally complex matrix, and buffers around sensitive areas. Management should maintain a diversity of species within and across functional groups. Highly focused management actions may be required to maintain keystone species and threatened species, and to control invasive species. These guiding principles provide a scientifically defensible starting point for the integration of conservation and production, which is urgently required from both an ecological and a long-term economic perspective. Biodiversity conservation in forestry and agricultural landscapes is important because (1) reserves alone will not protect biodiversity; (2) commodity production relies on vital services provided by biodiversity; and (3) biodiversity enhances resilience, or a system's capacity to recover from external pressures such as droughts or management mistakes. We suggest ten guiding principles to help maintain biodiversity, ecosystem function, and resilience in production landscapes. Landscapes should include structurally characteristic patches of native vegetation, corridors and stepping stones between them, a structurally complex matrix, and buffers around sensitive areas. Management should maintain a diversity of species within and across functional groups. Highly focused management actions may be required to maintain keystone species and threatened species, and to control invasive species. These guiding principles provide a scientifically defensible starting point for the integration of conservation and production, which is urgently required from both an ecological and a long‐term economic perspective.

In many parts of the world there is an urgent need for landscape restoration to conserve biodiversity. Landscape restoration is not straightforward, however, because many issues and processes must be understood for effective action to take place. In an attempt to guide restoration efforts for biodiversity conservation, Lambeck (1997, 1999) developed a taxon-based surrogate scheme called the focal-species approach. The focal-species approach involves the identification of a suite of species targeted for the management of threatening processes and vegetation-restoration efforts. Together, their "requirements for persistence define the attributes that must be present if [the landscape] is to meet the needs of the remaining biota" (Lambeck 1999). Some of our concerns with the focal-species approach include the following. First, the underlying theoretical basis of the focal-species approach is problematic. As part of a taxon-based surrogate scheme, a suite of focal species is presumed to act collectively as a surrogate for other elements of the biota. But taxon-based surrogate schemes have had limited success everywhere they have been applied. Second, the focal-species approach may be unsuitable for practical implementation, primarily because of the lack of data to guide the selection of a set of focal species in the majority of landscapes. We argue that restoration strategies should be based on appropriate theory, realistic assessment of available information, and an achievable outcome for the land managers who own or control the majority of land in the most significantly affected landscapes. Given the potential limitations of the focal-species approach, a mix of different strategies shouM be adopted in any given landscape and between different landscapes to spread risk of failure of any one approach. We believe that it is important to raise awareness about the potential limitations of the focal-species approach and to ensure that land managers do not assume it will inevitably lead to the conservation of all biota in a landscape.

We report on the effects of broad-scale restoration treatments on the ground layer of eucalypt grassy woodland in south-eastern Australia. The experiment was conducted in two conservation reserves from which livestock grazing had previously been removed. Changes in biomass, species diversity, ground-cover attributes and life-form were analysed over a 4-year period in relation to the following experimental interventions: (1) reduced kangaroo density, (2) addition of coarse woody debris and (3) fire (a single burn). Reducing kangaroo density doubled total biomass in one reserve, but no effects on exotic biomass, species counts or ground cover attributes were observed. Coarse woody debris also promoted biomass, particularly exotic annual forbs, as well as plant diversity in one of the reserves. The single burn reduced biomass, but changed little else. Overall, we found the main driver of change to be the favourable growth seasons that had followed a period of drought. This resulted in biomass increasing by 67%, (mostly owing to the growth of perennial native grasses), whereas overall native species counts increased by 18%, and exotic species declined by 20% over the 4-year observation period. Strategic management of grazing pressure, use of fire where biomass has accumulated and placement of coarse woody debris in areas of persistent erosion will contribute to improvements in soil and vegetation condition, and gains in biodiversity, in the future.

The management of landscapes for biological conservation and ecologically sustainable natural resource use are crucial global issues. Research for over two decades has resulted in a large literature, yet there is little consensus on the applicability or even the existence of general principles or broad considerations that could guide landscape conservation. We assess six major themes in the ecology and conservation of landscapes. We identify 13 important issues that need to be considered in developing approaches to landscape conservation. They include recognizing the importance of landscape mosaics (including the integration of terrestrial and aquatic areas), recognizing interactions between vegetation cover and vegetation configuration, using an appropriate landscape conceptual model, maintaining the capacity to recover from disturbance and managing landscapes in an adaptive framework. These considerations are influenced by landscape context, species assemblages and management goals and do not translate directly into on-the-ground management guidelines but they should be recognized by researchers and resource managers when developing guidelines for specific cases. Two crucial overarching issues are: (i) a clearly articulated vision for landscape conservation and (ii) quantifiable objectives that offer unambiguous signposts for measuring progress.

Seventy-one litters of kittens (mean litter size 4.4) were studied from birth to eight weeks of age in order to measure kitten growth and maternal body condition. Few sex differences in growth occur; male and female kittens place a similar burden on their lactating mother. A mother's weight (non-pregnant, non-lactating) interacts with litter size to determine the fate of her growing kittens. A large litter places a burden on both the mother and on the kittens, whose growth is affected; small mothers with large litters are particularly at risk. An acceleration in kitten growth occurs at about 32 days as the kittens take more solid food. This change in growth rate is more marked in large litters. Kittens of light mothers and kittens in large litters are weaned at a lower weight, and kittens of light mothers are weaned earlier. Our results indicate that, under poor environmental conditions, large litters would be less successful than small litters; kitten growth and survival would be affected and providing milk for a large litter would have a detrimental effect on the mother's health. The cost of lactation appears to have been a major evolutionary factor in determining mean litter size.