Towards sustainable management: Southern Africa's Afromontane, and Western Australia's Jarrah forests

We review the history of forest management in two southern hemisphere forest types: Western Australia's jarrah Eucalyptus marginata forests and the Afromontane forests of southern Africa to determine approaches for achieving sustainable forest management. We argue that despite major differences in the ecology and biogeography of these two forest types, a shared pattern in the history of exploitation may provide lessons for achieving sustainable management across forest types. While advanced silvicultural understanding has long been achieved in both forest types, this in itself has not led to either sustainable management or to public acceptance of forest management regimes. In both areas an early, rapid expansion of uncontrolled timber removal and in the number of operating timber mills was followed by controlled exploitation, a rapid decline in the numbers of mills and, more recently, a general decline in yield. In neither case was increased concern about conservation responsible for the reduction in either yield or in employment in the industry. Rather, in WA jarrah forests, amendments in purpose and tenure were subsequent to the loss of most mills and towns, while in southern Africa's Afromontane forests, timber workers were pensioned by 1939 because of scanty remaining merchantable timber. In the jarrah forests, we believe that the conflict generated by conservation concerns, reduced timber industry employment, and reduced benefits flowing to the communities adjacent to the logged forests, has fueled dissatisfaction with forest management outcomes. This has led to a new process in the preparation of forest management plans. Increased accountability and more realistic expectations of timber yield following productivity declines may mean the current plan for the forests of Western Australia can be used as an example to achieve sustainability in Mediterranean forest ecosystems. However, general acceptance of management regimes may not be achieved until the scale of logging operations is matched with local sustainability criteria. Increasing the area of reserves will not accelerate this process, but rather may impede it. Setting conservative overall yield estimates, and achieving local sustainability seem both to be necessary to achieve general acceptance of management regimes. A sustainable management system appears to have been achieved in the Afromontane forests and has led to the development and maintenance of support for small-scale operations to supply local timber needs from State managed forests. In both environments such a process is achievable because of the high value and specialized nature of the native forest timber resource, and because of the increasing availability of general purpose timber from plantations

Consequences of Broadscale Timber Plantations for Biodiversity in Cleared Rainforest Landscapes of Tropical and Subtropical Australia

In Australia, as in many countries, there has been a shift in timber production from native forests to plantations. While plantations are primarily considered an efficient means of producing timber, there is increasing interest in their potential contribution to biodiversity conservation. Plantations may have both positive and negative consequences for biodiversity, at a range of scales. We compiled a list of these consequences from the literature, and used them to assess plantation scenarios proposed for cleared rainforest landscapes in tropical and subtropical Australia. The scenarios were monocultures of: (i) hoop pine, (ii) exotic pine and (iii) eucalypts; (iv) mixed species plantations; (v) a mosaic of monoculture plantations; and (vi) a mosaic of plantations and ecological restoration plantings. Of these scenarios, plantations of eucalypts and exotic pines have the least positive consequences for biodiversity: they have little or no intrinsic value in rainforest landscapes, provide poor quality habitat for rainforest biota, and (particularly eucalypts) are characterised by a relatively open canopy which in cleared landscapes favours the recruitment of grasses and other weeds. The three scenarios based on plantations of rainforest trees have similar, moderately positive consequences for biodiversity, while a mosaic of plantations and restoration plantings has the most positive consequences for biodiversity in cleared rainforest landscapes. All scenarios may have negative impacts on biodiversity conservation if plantations replace remnant forest, provide habitat for weeds, or the tree species used in plantations or their genes escape into native forests. In practice, the relative importance of positive and negative impacts, and hence the ranking of scenarios may vary with landscape forest cover. Scenarios with strongly positive consequences for biodiversity would be favoured for the reforestation of heavily cleared landscapes, whereas scenarios with few negative consequences for biodiversity would be favoured in well-forested landscapes. Consequently, any plantation of rainforest trees may have acceptable consequences for biodiversity in well-forested landscapes, provided the trees are not invasive or carrying exotic genotypes, and plantations are managed to control weeds and feral animals. With the same caveats, plantations of exotic pines may also be acceptable from a biodiversity conservation perspective in well-forested landscapes. At present our capacity to design and manage rainforest plantations for both timber and biodiversity objectives is limited by a lack of information on factors affecting timber production, biodiversity values and trade offs or synergies between these objectives. Obtaining this information will require the integration of large-scale long-term biodiversity research in broadscale plantation projects

The capacity of refugia for conservation planning under climate change

Refugia – areas that may facilitate the persistence of species during large-scale, long-term climatic change – are increasingly important for conservation planning. There are many methods for identifying refugia, but the ability to quantify their potential for facilitating species persistence (ie their “capacity”) remains elusive. We propose a flexible framework for prioritizing future refugia, based on their capacity. This framework can be applied through various modeling approaches and consists of three steps: (1) definition of scope, scale, and resolution; (2) identification and quantification; and (3) prioritization for conservation. Capacity is quantified by multiple indicators, including environmental stability, microclimatic heterogeneity, size, and accessibility of the refugium. Using an integrated, semi-mechanistic modeling technique, we illustrate how this approach can be implemented to identify refugia for the plant diversity of Tasmania, Australia. The highest- capacity climate-change refugia were found primarily in cool, wet, and topographically complex environments, several of which we identify as high priorities for biodiversity conservation and management

Rapid characterisation of vegetation structure to predict refugia and climate change impacts across a global biodiversity hotspot

Identification of refugia is an increasingly important adaptation strategy in conservation planning under rapid anthropogenic climate change. Granite outcrops (GOs) provide extraordinary diversity, including a wide range of taxa, vegetation types and habitats in the Southwest Australian Floristic Region (SWAFR). However, poor characterization of GOs limits the capacity of conservation planning for refugia under climate change. A novel means for the rapid identification of potential refugia is presented, based on the assessment of local-scale environment and vegetation structure in a wider region. This approach was tested on GOs across the SWAFR. Airborne discrete return Light Detection And Ranging (LiDAR) data and Red Green and Blue (RGB) imagery were acquired. Vertical vegetation profiles were used to derive 54 structural classes. Structural vegetation types were described in three areas for supervised classification of a further 13 GOs across the region.Habitat descriptions based on 494 vegetation plots on and around these GOs were used to quantify relationships between environmental variables, ground cover and canopy height. The vegetation surrounding GOs is strongly related to structural vegetation types (Kappa = 0.8) and to its spatial context. Water gaining sites around GOs are characterized by taller and denser vegetation in all areas. The strong relationship between rainfall, soil-depth, and vegetation structure (R2 of 0.8–0.9) allowed comparisons of vegetation structure between current and future climate. Significant shifts in vegetation structural types were predicted and mapped for future climates. Water gaining areas below granite outcrops were identified as important putative refugia. A reduction in rainfall may be offset by the occurrence of deeper soil elsewhere on the outcrop. However, climate change interactions with fire and water table declines may render our conclusions conservative. The LiDAR-based mapping approach presented enables the integration of site-based biotic assessment with structural vegetation types for the rapid delineation and prioritization of key refugia

Comparative patterns of plant invasions in the mediterranean biome

The objective of this work was to compare and contrast the patterns of alien plant invasions in the world’s five mediterranean-climate regions (MCRs). We expected landscape age and disturbance history to have bearing on levels of invasion. We assembled a database on naturalized alien plant taxa occurring in natural and semi-natural terrestrial habitats of all five regions (specifically Spain, Italy, Greece and Cyprus from the Mediterranean Basin, California, central Chile, the Cape Region of South Africa and Southwestern - SW Australia). We used multivariate (hierarchical clustering and NMDS ordination) trait and habitat analysis to compare characteristics of regions, taxa and habitats across the mediterranean biome. Our database included 1627 naturalized species with an overall low taxonomic similarity among the five MCRs. Herbaceous perennials were the most frequent taxa, with SW Australia exhibiting both the highest numbers of naturalized species and the highest taxonomic similarity (homogenization) among habitats, and the Mediterranean Basin the lowest. Low stress and highly disturbed habitats had the highest frequency of invasion and homogenization in all regions, and high natural stress habitats the lowest, while taxonomic similarity was higher among different habitats in each region than among regions. Our analysis is the first to describe patterns of species characteristics and habitat vulnerability for a single biome. We have shown that a broad niche (i.e. more than one habitat) is typical of naturalized plant species, regardless of their geographical area of origin, leading to potential for high homogenization within each region. Habitats of the Mediterranean Basin are apparently the most resistant to plant invasion, possibly because their landscapes are generally of relatively recent origin, but with a more gradual exposure to human intervention over a longer period

Towards an eco-evolutionary understanding of endemism hotspots and refugia.

BackgroundRefugia are island-like habitats that are linked to long-term environmental stability and, as a result, high endemism. Conservation of refugia and endemism hotspots should be based on a deep ecological and evolutionary understanding of their functioning, which remains limited. Although functional traits can provide such insights, a corresponding, coherent framework is lacking.Proposed frameworkPlant communities in refugia and endemism hotspots should, due to long-term environmental stability, display unique functional characteristics linked to distinct phylogenetic patterns. Therefore, such communities should be characterized by a functional signature that exhibits: (1) distinct values and combinations of traits, (2) higher functional diversity and (3) a prevalence of similar traits belonging to more distantly related lineages inside, compared to outside, of endemism hotspots and refugia. While the limited functional trait data available from refugia and endemism hotspots do not allow these predictions to be tested rigorously, three potential applications of the functional signature in biogeography and conservation planning are highlighted. Firstly, it allows the functional characteristics of endemism hotspots and refugia to be identified. Secondly, the strength of the functional signature can be compared among these entities, and with the surrounding landscape, to provide an estimate of the capacity of endemism hotspots and refugia to buffer environmental changes. Finally, the pattern of the functional signature can reveal ecological and evolutionary processes driving community assembly and functioning, which can assist in predicting the effect of environmental changes (e.g. climate, land-use) on communities in endemism hotspots and refugia.ConclusionThe proposed functional signature concept allows the systematic integration of plant functional traits and phylogeny into the study of endemism hotspots and refugia, but more data on functional traits in these entities are urgently needed. Overcoming this limitation would facilitate rigorous testing of the proposed predictions for the functional signature, advancing the eco-evolutionary understanding of endemism hotspots and refugia

Rainforest timber plantations and the restoration of plant biodiversity in tropical and subtropical Australia

We compared the species richness, growth forms and assemblages of vascular plants in five types of rainforest reforestation with pasture and forest reference sites in tropical and subtropical Australia. These types include unmanaged regrowth, young and old monoculture plantations, young rainforest cabinet timber species plantations and plantings designed to restore natural rainforest communities. Patterns of species richness across these reforestation types differed between the tropics and subtropics, although all reforestation types supported fewer species than natural rainforest reference sites. In the tropics similar numbers of introduced (i.e. non-native) species occurred in all types of reforestation (with the exception of old plantations which included few introduced species) and pasture reference sites. This contrasts with the subtropics where the greatest numbers of introduced species were associated with cabinet timber plantings. Greater diversity of growth forms (including epiphytes and vines) occurred in rainforest reference sites than in any type of reforestation. The assemblages of canopy trees (including both planted species and recruits) varied in their resemblance to rainforest reference sites in the different types of reforestation in the two regions. However, there was a tendency for young plantations to be most dissimilar to rainforest reference sites. On the other hand, old (ca. 60 years) plantation sites in the tropics were similar to natural rainforest reference sites. This was due to their close proximity to remnants and low intensity management regimes.Because species richness and growth form obscures the importance of particular species in reforestation, we targeted eight common species (four native and four introduced) as exemplars of the possible biodiversity future under the different types of reforestation. These species demonstrated the individuality of species behaviour under different types of reforestation. Rainforest timber plantations can lead to increased biodiversity if they are designed to facilitate the colonization of rainforest taxa, and managed to favour processes associated with the development of a rainforest environment. Negative outcomes for rainforest biodiversity follow the establishment of non-rainforest species or processes (e.g. persistent high understorey light levels) not associated with a rainforest environment. Management and designs to minimize the need for ongoing intervention will be important economic considerations in future reforestation efforts aimed at restoring biodiversity

Diversity patterns in the steppe of argentinean southern patagonia: Environmental drivers and impact of grazing

The steppe ecosystem, mainly characterised by the presence of tussock, short grasses and shrubs, covers 85% of the total area in Santa Cruz Province and 25% in Tierra del Fuego Island. Most of the land in the Patagonian region has been influenced by domestic livestock grazing for more than 100 years. This has led to a substantial modification of the ecosystem and the original floristic patterns. Erosion and degradation processes have occurred in several areas of Patagonia mainly due to an overestimation of the carrying capacity of these rangelands. In this chapter we review patterns of plant and insect diversity in relation to environmental drivers and grazing impact in the steppe of Argentinian South Patagonia. In Santa Cruz, results from 141 sites indicated significant interactions between grazing and the abiotic environment (mainly water avalilability) on plant diversity. The complexity of these interactions indicated the need for examining patterns of species turnover at different spatial scales. Analysis of the steppe vegetation patterns from 113 sites along Tierra del Fuego Island demostrated differences related to geographical zones (North, Center, East and South), dominant vegetation types (grasslands, peatlands or shrublands) and disturbance impact (grazing, beavers or burned areas). Because insect diversity of Tierra del Fuego steppes is poorly known, coleopterans were selected as potential indicators of biodiversity using pitfalls traps in the same vegetation survey sites. We found significant changes in ground-active beetle assemblages generated by grazing and livestock activities, both in grassland, peatlands and shrublands. Therefore, this group of insects could be useful indicators of biodiversity conservation and ecosystem management.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria; Argentina. Universidad Nacional de la Patagonia Austral; ArgentinaFil: Lencinas, María Vanessa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Martínez Pastur, Guillermo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Wardell Johnson, Grant W.. Curtin University; AustraliaFil: Lasagno, Romina. Instituto Nacional de Tecnología Agropecuaria; Argentin

Diversity patterns in the steppe of Argentinean Southern Patagonia: Environmental drivers and impact of grazing

The steppe ecosystem, mainly characterised by the presence of tussock, short grasses and shrubs, covers 85% of the total area in Santa Cruz Province and 25% in Tierra del Fuego Island. Most of the land in the Patagonian region has been influenced by domestic livestock grazing for more than 100 years. This has led to a substantial modification of the ecosystem and the original floristic patterns. Erosion and degradation processes have occurred in several areas of Patagonia mainly due to an overestimation of the carrying capacity of these rangelands. In this chapter we review patterns of plant and insect diversity in relation to environmental drivers and grazing impact in the steppe of Argentinian South Patagonia. In Santa Cruz, results from 141 sites indicated significant interactions between grazing and the abiotic environment (mainly water avalilability) on plant diversity. The complexity of these interactions indicated the need for examining patterns of species turnover at different spatial scales. Analysis of the steppe vegetation patterns from 113 sites along Tierra del Fuego Island demostrated differences related to geographical zones (North, Center, East and South), dominant vegetation types (grasslands, peatlands or shrublands) and disturbance impact (grazing, beavers or burned areas). Because insect diversity of Tierra del Fuego steppes is poorly known, coleopterans were selected as potential indicators of biodiversity using pitfalls traps in the same vegetation survey sites. We found significant changes in ground-active beetle assemblages generated by grazing and livestock activities, both in grassland, peatlands and shrublands. Therefore, this group of insects could be useful indicators of biodiversity conservation and ecosystem management.EEA Santa CruzFil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Lencinas, María Vanessa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas (CADIC); Argentina.Fil: Martínez Pastur, Guillermo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas (CADIC); Argentina.Fil: Wardell-Johnson, Grant W. Curtin University. Curtin Institute for Biodiversity and Climate; Australia.Fil: Lasagno, Romina Gisele. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina

Data from: High species diversity and turnover in granite inselberg floras highlight the need for a conservation strategy protecting many outcrops

Determining patterns of plant diversity on granite inselbergs is an important task for conservation biogeography due to mounting threats. However, beyond the tropics there are relatively few quantitative studies of floristic diversity, or consideration of these patterns and their environmental, biogeographic and historical correlates for conservation. We sought to contribute broader understanding of global patterns of species diversity on granite inselbergs and inform biodiversity conservation in the globally significant Southwest Australian Floristic Region (SWAFR). We surveyed floristics from 16 inselbergs (478 plots) across the climate gradient of the SWAFR stratified into three major habitats on each outcrop. We recorded 1060 species from 92 families. At the plot level, local soil and topographic variables affecting aridity were correlated with species richness in herbaceous (HO) and woody vegetation (WO) of soil-filled depressions, but not in woody vegetation on deeper soils at the base of outcrops (WOB). At the outcrop level, bioclimatic variables affecting aridity were correlated with species richness in two habitats (WO and WOB) but, contrary to predictions from island biogeography, were not correlated with inselberg area and isolation in any of the three habitats. Species turnover in each of the three habitats was also influenced by aridity, being correlated with bioclimatic variables and with inter-plot geographic distance, and for HO and WO habitats with local site variables. At the outcrop level, species replacement was the dominant component of species turnover in each of the three habitats, consistent with expectations for long-term stable landscapes. Our results therefore highlight high species diversity and turnover associated with granite outcrop flora. Hence, effective conservation strategies will need to focus on protecting multiple inselbergs across the entire climate gradient of the region