Restoration of OCBILs in south-western Australia: Response to Hopper

In an authoritative review on biodiversity conservation in old, climatically buffered infertile landscapes (OCBILs) Hopper (2009) recently argued that Cramer et al. (2008) were ‘overly pessimistic’ to suggest that restoration of historical ecosystems on some old-fields of OCBILs in south-western Australia was unlikely. Here, we argue that this view was realistic rather than pessimistic, and that the conservation of OCBIL biota requires both a radical shift in the willingness of society to make the investment that is currently necessary to restore historical floristically rich OCBILs and further research to find more cost-effective options for broadscale restoration. Advancing the science and practice of ecological restoration in this landscape requires acknowledgement of current constraints. Ultimately, an approach that combines restoration and conservation is required to ensure the persistence of OCBIL biodiversity in the face of ongoing degradation and climate change.     

660. NUYTSIA FLORIBUNDA

Summary. Nuytsia floribunda (Labill.) R.Br. ex G.Don, a monotypic arborescent root hemiparasite endemic to the Southwest Australian Floristic Region, sister to all other showy mistletoes, is described and illustrated. A review is provided of its mythological and practical use by Noongar Aborigines, its discovery and early documentation by Europeans, and its phylogeny, biology, ecology and systematics. Experiences with its cultivation and propagation before and after it was discovered to be parasitic are discussed. Nuytsia provides a useful case study for testing many hypotheses developed in OCBIL theory, which aims to explain the evolution and ecology of, and best conservation practices for, biota on very old, climatically buffered, infertile landscapes (i.e. OCBILs), found especially in regions such as the Southwest Australian Floristic Region, the Greater Cape of South Africa and the Pantepui of Venezuela.     

Plant mineral nutrition in ancient landscapes: high plant species diversity on infertile soils is linked to functional diversity for nutritional strategies

Ancient landscapes, which have not been glaciated in recent times or disturbed by other major catastrophic events such as volcanic eruptions, are dominated by nutrient-impoverished soils. If these parts of the world have had a relatively stable climate, due to buffering by oceans, their floras tend to be very biodiverse. This review compares the functional ecophysiological plant traits that dominate in old, climatically buffered, infertile landscapes (OCBILS) with those commonly found in young, frequently disturbed, fertile landscapes (YODFELs). We show that, within the OCBILs of Western Australia, non-mycorrhizal species with specialised root clusters predominantly occur on the most phosphate-impoverished soils, where they co-occur with mycorrhizal species without such specialised root clusters. In global comparisons, we show that plants in OCBILs, especially in Western Australia, are characterised by very low leaf phosphorus (P) concentrations, very high N:P ratios, and very high LMA values (LMA = leaf mass per unit leaf area). In addition, we show that species in OCBILs are far more likely to show P-toxicity symptoms when exposed to slightly elevated soil P levels when compared with plants in YODFELs. In addition, some species in OCBILs exhibit a remarkable P-resorption proficiency, with some plants in Western Australia achieving leaf P concentrations in recently shed leaves that are lower than ever reported before. We discuss how this knowledge on functional traits can guide us towards sustainable management of ancient landscapes.     

Plant mineral nutrition in ancient landscapes: high plant species diversity on infertile soils is linked to functional diversity for nutritional strategies

Ancient landscapes, which have not been glaciated in recent times or disturbed by other major catastrophic events such as volcanic eruptions, are dominated by nutrient-impoverished soils. If these parts of the world have had a relatively stable climate, due to buffering by oceans, their floras tend to be very biodiverse. This review compares the functional ecophysiological plant traits that dominate in old, climatically buffered, infertile landscapes (OCBILS) with those commonly found in young, frequently disturbed, fertile landscapes (YODFELs). We show that, within the OCBILs of Western Australia, non-mycorrhizal species with specialised root clusters predominantly occur on the most phosphate-impoverished soils, where they co-occur with mycorrhizal species without such specialised root clusters. In global comparisons, we show that plants in OCBILs, especially in Western Australia, are characterised by very low leaf phosphorus (P) concentrations, very high N:P ratios, and very high LMA values (LMA = leaf mass per unit leaf area). In addition, we show that species in OCBILs are far more likely to show P-toxicity symptoms when exposed to slightly elevated soil P levels when compared with plants in YODFELs. In addition, some species in OCBILs exhibit a remarkable P-resorption proficiency, with some plants in Western Australia achieving leaf P concentrations in recently shed leaves that are lower than ever reported before. We discuss how this knowledge on functional traits can guide us towards sustainable management of ancient landscapes.     

Landscape and taxon age are associated with differing patterns of hybridization in two Eucalyptus (Myrtaceae) subgenera

Background and AimsHybridization is an important evolutionary process that can have a significant impact on natural plant populations. Eucalyptus species are well known for weak reproductive barriers and extensive hybridization within subgenera, but there is little knowledge of whether patterns of hybridization differ among subgenera. Here, we examine eucalypts of Western Australia’s Stirling Range to investigate how patterns of hybridization are associated with landscape and taxon age between the two largest Eucalyptus subgenera: Eucalyptus and Symphyomyrtus. In doing so, we tested a hypothesis of OCBIL (old, climatically buffered, infertile landscape) theory that predicts reduced hybridization on older landscapes.MethodsSingle nucleotide polymorphism markers were applied to confirm the hybrid status, parentage and genetic structure of five suspected hybrid combinations for subg. Eucalyptus and three combinations for subg. Symphyomyrtus.Key ResultsEvidence of hybridization was found in all combinations, and parental taxa were identified for most combinations. The older parental taxa assessed within subg. Eucalyptus, which are widespread on old landscapes, were identified as well-defined genetic entities and all hybrids were exclusively F₁ hybrids. In addition, many combinations showed evidence of clonality, suggesting that the large number of hybrids recorded from some combinations is the result of long-term clonal spread following a few hybridization events rather than frequent hybridization. In contrast, the species in subg. Symphyomyrtus, which typically occur on younger landscapes and are more recently evolved, showed less distinction among parental taxa, and where hybridization was detected, there were high levels of introgression.ConclusionsReduced hybridization in subg. Eucalyptus relative to extensive hybridization in subg. Symphyomyrtus affirmed the hypothesis of reduced hybridization on OCBILs and demonstrate that clade divergence times, landscape age and clonality are important drivers of differing patterns of speciation and hybridization in Eucalyptus.     

Habitat quality of source patches and connectivity in fragmented landscapes

Because spatial connectivity is critical to dispersal success and persistence of species in highly fragmented landscapes, the way that we envision and measure connectivity is consequential for biodiversity conservation. Connectivity metrics used for predictive modeling of spatial turnover and patch occupancy for metapopulations, such as with Incidence Function Models (IFM), incorporate distances to and sizes of possible source populations. Here, our focus is on whether habitat quality of source patches also is considered in these connectivity metrics. We propose that effective areas (weighted by habitat quality) of source patches should be better surrogates for population size and dispersal potential compared to unadjusted patch areas. Our review of a representative sample of the literature revealed that only 12.5% of studies incorporated habitat quality of source patches into IFM-type connectivity metrics. Quality of source patches generally was not taken into account in studies even if habitat quality of focal patches was included in analyses. We provide an empirical example for a metapopulation of a rare wetland species, the round-tailed muskrat (Neofiber alleni), demonstrating that a connectivity metric based on effective areas of source patches better predicts patch colonization and occupancy than a metric that used simple patch areas. The ongoing integration of landscape ecology and metapopulation dynamics could be hastened by incorporating habitat quality of source patches into spatial connectivity metrics applied to species conservation in fragmented landscapes.     

Miniaturizing landscapes to understand species distributions

Species’ geographic distributions shape global patterns of biodiversity and therefore have long been of interest to ecology and conservation. Theory has generated valuable hypotheses about how landscape structure, dispersal, biotic interactions and evolution shape range dynamics, but most predictions have not been tested on real organisms because key variables are difficult to isolate, replicate or manipulate in natural ecosystems. An exciting and rapidly emerging approach is to extend classical microcosm and mesocosm systems to create experimental ‘micro-landscapes’. By enabling researchers to manipulate geographic features of interest, replicate landscapes, control colonization and follow dynamics across evolutionary timescales, micro-landscapes allow explicit tests of the ecological and evolutionary underpinnings of species distributions. Here we review the micro-landscape systems being used to advance biogeography, the major insights they have generated thus far, and the features that limit their application to some scenarios. We end by highlighting important questions about species’ biogeography that are ripe for testing with experimental micro-landscapes, particularly those of immediate concern given rapid global change, such as range contractions and constraints to range expansion.     

Landscape scale conservation: resources, behaviour, the matrix and opportunities

Landscape scale conservation efforts are becoming more commonplace in conservation, with a move from single species to multi-species initiatives. These initiatives are reliant on modelling processes, largely underpinned by metapopulation models. We argue that generic models developed for individual species in particular landscapes over selected time periods may only be applicable to alternative landscapes and time periods in restricted circumstances. Variability in species responses to landscapes and environmental conditions is dependent on a range of species-specific intrinsic characteristics, dependent on their responses to resources, (including weather) and also individual states. We propose that the behavioural component of how species respond to resources needs to be taken into account in modelling species responses to landscape, and therefore how limited resources for conservation are deployed. Species behaviours are inherently complex. We argue that because of this complexity the conservation of the majority of species, especially of the least rare, may be best served if conservation effort is additionally focused on increasing landscape heterogeneity and disturbance. This may also facilitate persistence in the face of climate change. We suggest that heterogeneity should be promoted through agri-environment schemes.     

Persistence and spread of stage-structured populations in heterogeneous landscapes

Journal of Mathematical Biology - Conditions for population persistence in heterogeneous landscapes and formulas for population spread rates are important tools for conservation ecology and...     

Prioritizing multiple-use landscapes for conservation: methods for large multi-species planning problems

Across large parts of the world, wildlife has to coexist with human activity in highly modified and fragmented landscapes. Combining concepts from population viability analysis and spatial reserve design, this study develops efficient quantitative methods for identifying conservation core areas at large, even national or continental scales. The proposed methods emphasize long-term population persistence, are applicable to both fragmented and natural landscape structures, and produce a hierarchical zonation of regional conservation priority. The methods are applied to both observational data for threatened butterflies at the scale of Britain and modelled probability of occurrence surfaces for indicator species in part of Australia. In both cases, priority landscapes important for conservation management are identified.     

The role of non-natural foods in the nutritional strategies of monkeys in a human-modified mosaic landscape

Many tropical animals inhabit mosaic landscapes including human-modified habitat. In such landscapes, animals commonly adjust feeding behavior, and may incorporate non-natural foods. These behavioral shifts can influence consumers' nutritional states, with implications for population persistence. However, few studies have addressed the nutritional role of non-natural food. We examined nutritional ecology of wild blue monkeys to understand how dietary habits related to non-natural foods might support population persistence in a mosaic landscape. We documented prevalence and nutritional composition of non-natural foods in monkey diets to assess how habitat use influenced their consumption, and their contribution to nutritional strategies. While most energy and macronutrients came from natural foods, subjects focused non-natural feeding activity on five exotic plants, and averaged about a third of daily calories from non-natural foods. Most non-natural food calories came from non-structural carbohydrates and least from protein. Consumption of non-natural foods related to time in human-modified habitats, which two groups used non-randomly. Non-natural and natural foods were similar in nutrients, and the amount of non-natural food consumed drove variation in nutritional strategy. When more daily calories came from non-natural foods, females consumed a higher ratio of non-protein energy to protein (NPE:P). Females also prioritized protein while allowing NPE:P to vary, increasing NPE while capitalizing on non-natural foods. Overall, these tropical mammals achieved a similar nutrient balance regardless of their intake of non-natural foods. Forest and forest-adjacent areas with non-natural vegetation may provide adequate nutrient access for consumers, and thus contribute to wildlife conservation in mosaic tropical landscapes.     

Epilogue: Toward a Transdisciplinary Science of Ecological and Cultural Landscape Restoration

To bridge the gaps between restoration as a science and as a practice, restoration ecology has to broaden its scope toward transdisciplinarity in close cooperation with landscape ecologists and other holistic environmentally oriented scientists, professionals, practitioners, and stakeholders. For restoration, the ongoing transdisciplinary scientific revolution has opened new insights to cope with the complex bio‐hydro‐ and human‐ecological network relations. The Total Human Ecosystem (THE), integrating humans with all other organisms and their total environment at the highest level of the global hierarchy, should become the unifying holistic paradigm for all synthetic “eco‐disciplines.” These should link ecological knowledge, wisdom, and ethics with their scientific and professional expertise from the natural and social sciences and the humanities. As the tangible matrix for all organisms, including humans, our industrial Total Human Landscape is the concrete spatial and functional system of the THE. It forms a closely interlaced network of solar energy–powered natural and seminatural biosphere landscapes and fossil energy–powered urban and agro‐industrial technosphere landscapes. The self‐organizing and self‐creative restoration capacities of biosphere landscapes are driven by mutually amplifying auto‐ and cross‐catalytic feedback loops, but the rapidly expanding technosphere landscapes are driven by destabilizing “run‐away” feedback loops. To prevent a global breakdown and to ensure the sustainable future for both humankind and nature, these positive feedbacks have to be counteracted by restraining, cultural feedbacks of environmental planning and management, conservation, and restoration. As the theme of this special issue alludes to, this template should become an integral part of an urgently needed sustainability revolution, to which the transdisciplinary landscape restoration could contribute its important share.     

Recolonization of forest fragments by a native rodent following experimental ‘extinctions’

The movement of organisms between subdivided populations is considered a key influence on the persistence of species in modified landscapes. In particular, the ability to recolonize ‘empty’ fragments of habitat is directly relevant to conservation management, and to understanding the link between pattern and process in metapopulations. We studied the movement and recolonization ability of the bush rat, Rattus fuscipes, in a highly fragmented agricultural landscape in south‐western Victoria, Australia. Populations were monitored in seven small (<2.5 ha) and two large (>49 ha) forest fragments before removal of all residents from four of the small fragments. Subsequent monitoring (for up to 16 months) allowed the detection of colonizing individuals, and comparisons between ‘experimental’ and ‘control’ fragments. Rattus fuscipes readily moved between fragments and successfully recolonized (i.e. both males and females arrived) two of four fragments in which extinctions were simulated. A single male moved into a third experimental fragment. In one fragment, new animals were detected 1 month after the removal of residents, indicating that recolonization can occur rapidly. Dispersers were not a random sample of the population: although both males and females, and adults and sub‐adults were recorded dispersing, adult males in reproductive condition predominated. Functional connectivity appears to be high for R. fuscipes in the study landscape. Results from this manipulative experiment provide direct empirical evidence that a capacity for movement allows recolonization of fragments of suitable habitat and is a key process responsible for species persistence in fragmented landscapes, as predicted by theory.     

The Effects of Landscape Modifications on the Long-Term Persistence of Animal Populations

Background

The effects of landscape modifications on the long-term persistence of wild animal populations is of crucial importance to wildlife managers and conservation biologists, but obtaining experimental evidence using real landscapes is usually impossible. To circumvent this problem we used individual-based models (IBMs) of interacting animals in experimental modifications of a real Danish landscape. The models incorporate as much as possible of the behaviour and ecology of four species with contrasting life-history characteristics: skylark (Alauda arvensis), vole (Microtus agrestis), a ground beetle (Bembidion lampros) and a linyphiid spider (Erigone atra). This allows us to quantify the population implications of experimental modifications of landscape configuration and composition.

Methodology/Principal Findings

Starting with a real agricultural landscape, we progressively reduced landscape complexity by (i) homogenizing habitat patch shapes, (ii) randomizing the locations of the patches, and (iii) randomizing the size of the patches. The first two steps increased landscape fragmentation. We assessed the effects of these manipulations on the long-term persistence of animal populations by measuring equilibrium population sizes and time to recovery after disturbance. Patch rearrangement and the presence of corridors had a large effect on the population dynamics of species whose local success depends on the surrounding terrain. Landscape modifications that reduced population sizes increased recovery times in the short-dispersing species, making small populations vulnerable to increasing disturbance. The species that were most strongly affected by large disturbances fluctuated little in population sizes in years when no perturbations took place.

Significance

Traditional approaches to the management and conservation of populations use either classical methods of population analysis, which fail to adequately account for the spatial configurations of landscapes, or landscape ecology, which accounts for landscape structure but has difficulty predicting the dynamics of populations living in them. Here we show how realistic and replicable individual-based models can bridge the gap between non-spatial population theory and non-dynamic landscape ecology. A major strength of the approach is its ability to identify population vulnerabilities not detected by standard population viability analyses.     

Natural and human impact in Mediterranean landscapes: An intriguing puzzle or only a question of time?

Time is a key factor to understand the effects of disturbance on natural communities or ecosystems. In Mediterranean landscapes, where nature and humans have been strongly intermingling since mid-Holocene, the relationships between plant ecology and palaeoecology and their role for the interpretation of natural and anthropogenic changes still needs to be clearly understood. Ecology and palaeoecology are both investigating such problems, but each of them cannot disentangle the specific role played by nature and by humans in shaping the present plant communities and landscapes. A new age of cooperation among researchers in ecology and palaeoecology is needed, and the integration of these closely related but separated research fields is necessary to explain the resulting dynamic puzzle. Plant ecologists should avoid the oversimplification of the actual causes as the exclusive drivers of plant communities and landscapes and force the exploitation of the available data to generate and test new hypotheses for past, present and future environmental reconstructions and management. Even when planning for the future biodiversity conservation, we need to properly use the existing information about millennia of human effects on the natural biotas, to properly set landscape management and conservation priorities.     

Australia offers unique insight into the ecology of arbuscular mycorrhizal fungi: An opportunity not to be lost

Typified by ancient soils and unique assemblages of flora, Australia provides opportunities to expand our understanding of arbuscular mycorrhizal (AM) fungi. Despite their ubiquity, key aspects of Australian AM fungal ecology remain buried due to our limited knowledge of their biogeography and their potential adaptation to Australia's environmental conditions. This knowledge gap is particularly extraordinary given that the characteristics of the Australian environment are likely to provide unique insights into AM fungal ecology and evolution. Extensive exploration of the diversity and distribution of AM fungi across the continent is overdue. In pursuit of this goal, ecologists should employ the most effective and pragmatic molecular approaches, while making use of well-curated databases. We urge researchers to examine the biogeography of Australian AM fungi meaningfully, leveraging the distinctive attributes of Australian landscapes, such as the demographics of plant mycorrhizal types and the characteristic interplay with fire. Documenting AM fungal communities across Australia will not only provide unique insights into their ecology but is also pivotal to being able to incorporate these organisms into land management for conservation, restoration and sustainable agriculture.     

Chemical Ecology and Biomolecular Evolution

The belief in the Darwinian theory of evolution appeared to be shaken when one tried to interpret statements of molecular biology in it. As a consequence there arose a theory of non-Darwinian neutral evolution. The supporters of this theory believe that under natural conditions no factors exist which can distinguish and select organisms on their internal (molecular) structure. In the opinion of these neutralists natural selection cannot in principle control the molecular constitution of organisms. Contrary to the viewpoint of the critics of neutralism it is impossible to admit that nucleic acids, proteins and other biomolecules can evolve without the participation of natural selection. This controversy in contemporary theoretical biology can be solved by integrating the conceptions of molecular ecology with Darwinian theory. Molecular ecology acknowledges the interactions of organisms by means of chemical substances synthesized by them. Such chemical ecological factors play a leading part in the selective stages of biomolecular evolution. These diverse chemical ecological interrelations take place intensively when living beings interact with parasitic microbes.     

Effects of temporal variability on rare plant persistence in annual systems

Traditional conservation biology regards environmental fluctuations as detrimental to persistence, reducing long-term average growth rates and increasing the probability of extinction. By contrast, coexistence models from community ecology suggest that for species with dormancy, environmental fluctuations may be essential for persistence in competitive communities. We used models based on California grasslands to examine the influence of interannual fluctuations in the environment on the persistence of rare forbs competing with exotic grasses. Despite grasses and forbs independently possessing high fecundity in the same types of years, interspecific differences in germination biology and dormancy caused the rare forb to benefit from variation in the environment. Owing to the buildup of grass competitors, consecutive favorable years proved highly detrimental to forb persistence. Consequently, negative temporal autocorrelation, a low probability of a favorable year, and high variation in year quality all benefited the forb. In addition, the litter produced by grasses in a previously favorable year benefited forb persistence by inhibiting its germination into highly competitive grass environments. We conclude that contrary to conventional predictions of conservation and population biology, yearly fluctuations in climate may be essential for the persistence of rare species in invaded habitats.     

Temperate mountain grasslands: a climate‐herbivore hypothesis for origins and persistence

Temperate montane grasslands and their unique biotas are declining worldwide as they are increasingly being invaded by forests. The origin and persistence of these landscapes have been the focus of such controversy that in many areas their conservation is in doubt. In the USA some biologists have largely dismissed the grass balds of the Southern Appalachians as human artifacts or anomalous and transitory elements of regional geography, worthy of only limited preservation efforts. On the basis of information from biogeography, community ecology, regional history and palaeontology and from consideration of two other montane grassland ecosystems—East Carpathian poloninas and Oregon Coast Range grass balds—we hypothesize that these landscapes are more widespread than was formerly recognized; they are, in many cases, natural and ancient and largely owe their origin and persistence to past climatic extremes and the activities of large mammalian herbivores.