Optimal management of a flammable forest providing timber and carbon sequestration benefits: an Australian case study

In deciding to keep or fell a forest stand given its age, the risk of loss of timber through wildfire is an important consideration. If trees also have value from sequestration of carbon, another effect of fire is the unplanned loss of stored carbon. Factors affecting the decision to keep or fell trees, and how much to spend on fire protection, are investigated using stochastic dynamic programming, using carbon sequestration in stands of mountain ash in Victoria as a case study. The effect of treating sawlogs as a permanent carbon sink after harvesting is explored.Forest management, timber, carbon, dynamic, programming, Resource /Energy Economics and Policy,

Cambio y restauración del hábitat: respuestas de una especie de mamíferos del suelo forestal a las manipulaciones de los árboles caídos en bosques inundados

In forests and woodlands, fallen timber (logs and large branches) is an important habitat element for many species of animals. Fallen timber has been systematically stripped in many forests, eliminating an important structural element. This study describes results of a "meso–scale" experiment in which fallen timber was manipulated in a floodplain forest of the Murray River in south–eastern Australia. A thousand tons of wood were redistributed after one–year’s pre–manipulation monitoring, while a further two–year's post–manipulation monitoring was conducted. The response of the main forest–floor small–mammal species, the Yellow–footed Antechinus Antechinus flavipes, to alterations of fallen–wood loads is documented. Results of the experiment will help to frame guidelines for fallen–timber management in these extensive floodplain forests.En los bosques y montes los árboles caídos (troncos y ramas gruesas) constituyen un importante elemento del hábitat para muchas especies de animales. Los árboles caídos han sido sistemáticamente descortezados en muchos bosques, eliminándose así un importante elemento estructural. Este estudio describe resultados de un experimento a escala mediana en el que los árboles caídos fueron manipulados en un bosque inundado del río Murray, en el sureste de Australia. Se redistribuyeron 1.000 toneladas de madera después de efectuar un control previo a la manipulación durante un año, realizándose otro control durante dos años después de la manipulación. Se documenta la respuesta de la especie de mamífero del suelo del bosque, el ratón marsupial de pies amarillos Antechinus flavipes, a las alteraciones de la madera caída. Los resultados de este trabajo pueden servir de ayuda para elaborar unas directrices marco para la gestión de los árboles caídos en bosques inundados

Where and when to revegetate : a quantitative method for scheduling landscape reconstruction

Restoration of native vegetation is required in many regions of the world, but determining priority locations for revegetation is a complex problem. We consider the problem of determining spatial and temporal priorities for revegetation to maximize habitat for 62 bird species within a heavily cleared agricultural region, 11 000 km2 in area. We show how a reserve-selection framework can be applied to a complex, large-scale restoration-planning problem to account for multi-species objectives and connectivity requirements at a spatial extent and resolution relevant to management. Our approach explicitly accounts for time lags in planting and development of habitat resources, which is intended to avoid future population bottlenecks caused by delayed provision of critical resources, such as tree hollows. We coupled species-specific models of expected habitat quality and fragmentation effects with the dynamics of habitat suitability following replanting to produce species-specific maps for future times. Spatial priorities for restoration were determined by ranking locations (150-m grid cells) by their expected contribution to species habitat through time using the conservation planning tool, ‘‘Zonation.’’ We evaluated solutions by calculating expected trajectories of habitat availability for each species. We produced a spatially explicit revegetation schedule for the region that resulted in a balanced increase in habitat for all species. Priority areas for revegetation generally were clustered around existing vegetation, although not always. Areas on richer soils and with high rainfall were more highly ranked, reflecting their potential to support high-quality habitats that have been disproportionately cleared for agriculture. Accounting for delayed development of habitat resources altered the rank-order of locations in the derived revegetation plan and led to improved expected outcomes for fragmentation-sensitive species. This work demonstrates the potential for systematic restoration planning at large scales that accounts for multiple objectives, which is urgently needed by land and natural resource managers

Human-induced biotic invasions and changes in plankton interaction networks

Summary: Pervasive and accelerating changes to ecosystems due to human activities remain major sources of uncertainty in predicting the structure and dynamics of ecological communities. Understanding which biotic interactions within natural multitrophic communities are weakened or augmented by invasions of non-native species in the context of other environmental pressures is needed for effective management. We used multivariate autoregressive models with detailed time-series data from largely freshwater and brackish regions of the upper San Francisco Estuary to assess the topology, direction and strength of trophic interactions following major invasions and establishment of non-native zooplankton in the early 1990s. We simultaneously compared the effects of fish and clam predation, environmental temperature and salinity intrusion using time-series data from >60 monitoring locations spanning more than three decades. We found changes in the networks of biotic interactions in both regions after the major zooplankton invasions. Our results imply an increased pressure on native herbivores; intensified negative interactions between herbivores and omnivores; and stronger bottom-up influence of juvenile copepods but weaker influence of phytoplankton as a resource for higher trophic levels following the invasions. We identified salinity intrusion as a primary pressure but showed relatively stronger importance of biotic interactions for understanding the dynamics of entire communities. Synthesis and applications. Our findings highlight the dynamic nature of biotic interactions and provide evidence of how simultaneous invasions of exotic species may alter interaction networks in diverse natural ecosystems over large spatial and temporal scales. Efforts to restore declining fish stocks may be in vain without fully considering the trophic dynamics that limit the flow of energy to target populations. Focusing on multitrophic interactions that may be threatened by invasions rather than a limited focus on responses of individual species or diversity is likely to yield more effective management strategies. © 2014 British Ecological Society

Habitat change and restoration: Responses of a forest-floor mammal species to manipulations of fallen timber in floodplain forests

In forests and woodlands, fallen timber (logs and large branches) is an important habitat element for many species of animals. Fallen timber has been systematically stripped in many forests, eliminating an important structural element. This study describes results of a ‘meso-scale’ experiment in which fallen timber was manipulated in a floodplain forest of the Murray River in south-eastern Australia. A thousand tons of wood were redistributed after one-year’s pre-manipulation monitoring, while a further two-year’s post-manipulation monitoring was conducted. The response of the main forest-floor small-mammal species, the Yellow-footed Antechinus Antechinus flavipes, to alterations of fallen-wood loads is documented. Results of the experiment will help to frame guidelines for fallen-timber management in these extensive floodplain forests

Assessing the umbrella value of a range-wide conservation network for Jaguars (Panthera onca)

Umbrella species are employed as conservation short-cuts for the design of reserves or reserve networks. However, empirical data on the effectiveness of umbrellas is equivocal, which has prevented more widespread application of this conservation strategy. We perform a novel, large-scale evaluation of umbrella species by assessing the potential umbrella value of a jaguar (Panthera onca) conservation network (consisting of viable populations and corridors) that extends from Mexico to Argentina. Using species richness, habitat quality, and fragmentation indices of similar to 1500 co-occurring mammal species, we show that jaguar populations and corridors overlap a substantial amount and percentage of high-quality habitat for co-occurring mammals and that the jaguar network performs better than random networks in protecting high-quality, interior habitat. Significantly, the effectiveness of the jaguar network as an umbrella would not have been noticeable had we focused on species richness as our sole metric of umbrella utility. Substantial inter-order variability existed, indicating the need for complementary conservation strategies for certain groups of mammals. We offer several reasons for the positive result we document, including the large spatial scale of our analysis and our focus on multiple metrics of umbrella effectiveness. Taken together, our results demonstrate that a regional, single-species conservation strategy can serve as an effective umbrella for the larger community and should help conserve viable populations and connectivity for a suite of co-occurring mammals. Current and future range-wide planning exercises for other large predators may therefore have important umbrella benefits

Responses of floodplain birds to high-amplitude precipitation fluctuations over two decades

Globally, high-amplitude variation in weather (e.g. precipitation) is increasing in frequency and magnitude. This appears to be so for the southern Murray-Darling Basin, Australia, where droughts of unprecedented (in the instrumental record, extending back to the mid-1800s) depth and duration (1997–first half of 2010; second half of 2012–) are being punctuated by extreme wet periods, albeit of shorter duration (‘Big Wet’, second half of 2010–first half of 2012). We have previously reported on the responses of floodplain-forest birds to the cessation of the longest recorded drought (‘Big Dry’, 1997–first half of 2010), but we found little evidence of a rebound, at least shortly after the Big Wet. However, we reasoned that there may have been insufficient time for the birds to have responded in that short time, so we repeated the survey program 5 years after the end of the Big Wet (2017). Bird occurrences, reproductive activity and success were substantially greater compared with late in the Big Dry (2009) than they had been soon after the Big Wet (2013). However, bird occurrences still fell well below measurements in the early-Big Dry (1998), so that the avifauna appears to be in decline, most probably because the length of drought periods far exceeds that of wet periods giving the birds too little time to recover fully. © 2022 The Authors. Austral Ecology published by John Wiley & Sons Australia, Ltd on behalf of Ecological Society of Australia

Is Landscape Context Important for Riparian Conservation? Birds in Grassy Woodland

An important challenge for riparian management is to determine the extent to which landscape context influences the faunal assemblages of riparian habitats. We examined this challenge in the variegated landscapes of southeastern Queensland, Australia where riparian vegetation is surrounded by both extensive grazing and intensive cropping. We investigated whether riparian habitats adjacent to different landuses support similar bird assemblages. Three types of riparian habitat condition were sampled (uncleared ungrazed; uncleared grazed; cleared grazed) in four different land-use contexts (ungrazed woodland; grazed woodland; native pasture; crop) although only six of the twelve possible treatment combinations were available. Eighty percent of bird species responded significantly to changes in both riparian habitat condition and landscape context, while fewer than 50% of species were significantly influenced by landscape context alone. The influence of landscape context on the bird assemblage increased as the surrounding land use became more intensive (e.g. woodland to native pasture to crop). Riparian zones have been shown to have consistently high biodiversity values relative to their extent. These findings suggest it is not enough to conserve riparian habitats alone, conservation and restoration plans must also take into consideration landscape context, particularly when that context is intensively used land