Leonie E. Valentine

Advances in restoration ecology: rising to the challenges of the coming decades

Simultaneous environmental changes challenge biodiversity persistence and human wellbeing. The science and practice of restoration ecology, in collaboration with other disciplines, can contribute to overcoming these challenges. This endeavor requires a solid conceptual foundation based in empirical research which confronts, tests and influences theoretical developments. We review conceptual developments in restoration ecology over the last 30 years. We frame our review in the context of changing restoration goals which reflect increased societal awareness of the scale of environmental degradation and the recognition that inter-disciplinary approaches are needed to tackle environmental problems. Restoration ecology now encompasses facilitative interactions and network dynamics, trophic cascades, and above- and below ground linkages. It operates in a non-equilibrium, alternative states framework, at the landscape scale, and in response to changing environmental, economic and social conditions. Progress has been marked by conceptual advances in the fields of trait-environment relationships, community assembly, and understanding the links between biodiversity and ecosystem functioning. Conceptual and practical advances have been enhanced by applying evolving technologies, including treatments to increase seed germination and overcome recruitment bottlenecks, high throughput DNA sequencing to elucidate soil community structure and function, and advances in satellite technology and GPS tracking to monitor habitat use. The synthesis of these technologies with systematic reviews of context dependencies in restoration success, model based analyses and consideration of complex socio-ecological systems will allow generalizations to inform evidence based interventions. Ongoing challenges include setting realistic, socially acceptable goals for restoration under changing environmental conditions, and prioritizing actions in an increasingly space-competitive world. Ethical questions also surround the use of genetically modified material, translocations, taxon substitutions, and de-extinction, in restoration ecology. Addressing these issues, as the Ecological Society of America looks to its next century, will require current and future generations of researchers and practitioners, including economists, engineers, philosophers, landscape architects, social scientists and restoration ecologists, to work together with communities and governments to rise to the environmental challenges of the coming decades.

Effects of Weed-Management Burning on Reptile Assemblages in Australian Tropical Savannas

Fire is frequently used for land management purposes and may be crucial for effective control of invasive non-native plants. Nevertheless, fire modifies environments and may affect nontarget native biodiversity, which can cause conflicts for conservation managers. Native Australian reptiles avoid habitat invaded by the alien plant rubber vine (Cryptostegia grandiflora) and may be susceptible to the impacts of burning, a situation that provides a model system in which to examine possible conservation trade-offs between managing invasive plants and maintaining native biodiversity. We used replicated, experimental fire treatments (unburned, dry-season burned, and wet-season burned) in 2 habitats (riparian and adjacent open woodland) to examine the short- (within 12 months of fire) and longer-term (within 3 years of fire) changes of reptile assemblages in response to wet- and dry-season burning for weed management in tropical savannas of northern Australia. Within 12 months of fire, abundances of the skink Carlia munda (Scincidae) were higher in the burned sites, but overall reptile composition was structured by habitat type rather than by effects of burning. Within 3 years of a fire, the effects of fire were evident. Reptiles, especially the gecko Heteronotia binoei (Gekkonidae), were least abundant in dry-season burned sites; litter-associated species, including Carlia pectoralis (Scincidae), were rarely observed in burned habitat; and there were fewer species in the wet-season burned sites. Reptile abundance was associated with vegetation structure, which suggests that fire-induced changes detrimentally altered the availability of resources for some reptiles, particularly leaf-litter species. Invasive alien plants, such as rubber vine, have severe effects on native biodiversity, and control of such species is a fundamental land management objective. Nevertheless, fire management of invasive alien plants may adversely affect native biodiversity, creating a conservation conundrum. In such scenarios, land managers will need to identify the most desired conservation goal and consider the consequences for native biota.

Burning in Banksia Woodlands How does the Fire-Free period influence reptile communities?

Fire is an important management tool for both hazard reduction burning and maintenance of biodiversity. The impact of time since last fire on fauna is an important factor to understand as land managers often aim for prescribed burning regimes with specific fire-free intervals. However, our current understanding of the impact of time since last fire on fauna is largely unknown and likely dependent on vegetation type. We examined the responses of reptiles to fire age in banksia woodlands, and the interspersed melaleuca damplands among them, north of Perth, Western Australia, where the current prescribed burning regime is targeting a fire-free period of 8–12 years. The response of reptiles to fire was dependent on vegetation type. Reptiles were generally more abundant (e.g. Lerista elegans and Ctenophorus adelaidensis) and specious in banksia sites. Several species (e.g. Menetia greyii, Cryptoblepharus buchananii) preferred long unburnt melaleuca sites (>16 years since last fire, YSLF) compared to recently burnt sites (<12 YSLF). Several of the small elapids (e.g. the WA priority listed species Neelaps calonotus) were only detected in older-aged banksia sites (>16 YSLF). The terrestrial dragon C. adelaidensis and the skink Morethia obscura displayed a strong response to fire in banksia woodlands only. Highest abundances of the dragon were detected in the recently burnt (<7 YSLF) and long unburnt (>35 YSLF) banksia woodlands, while the skink was more abundant in older sites. Habitats from a range of fire ages are required to support the reptiles we detected, especially the longer unburnt (>16 YSLF) melaleuca habitat. Current burning prescriptions are reducing the availability of these older habitats.

The precision problem in conservation and restoration

Within the varied contexts of environmental policy, conservation of imperilled species populations, and restoration of damaged habitats, an emphasis on idealized optimal conditions has led to increasingly specific targets for management. Overly-precise conservation targets can reduce habitat variability at multiple scales, with unintended consequences for future ecological resilience. We describe this dilemma in the context of endangered species management, stream restoration, and climate-change adaptation. Inappropriate application of conservation targets can be expensive, with marginal conservation benefit. Reduced habitat variability can limit options for managers trying to balance competing objectives with limited resources. Conservation policies should embrace habitat variability, expand decision-space appropriately, and support adaptation to local circumstances to increase ecological resilience in a rapidly changing world.

Foraging activity by the southern brown bandicoot (Isoodon obesulus) as a mechanism for soil turnover

Abstract. Mammals that forage for food by biopedturbation can alter the biotic and abiotic characteristics of their habitat, influencing ecosystem structure and function. Bandicoots, bilbies, bettongs and potoroos are the primary digging marsupials in Australia, although most of these species have declined throughout their range. This study used a snapshot approach to estimate the soil turnover capacity of the southern brown bandicoot (Isoodon obesulus, Shaw 1797), a persisting digging Australian marsupial, at Yalgorup National Park, Western Australia. The number of southern brown bandicoots was estimated using mark–recapture techniques. To provide an index of digging activity per animal, we quantified the number of new foraging pits and bandicoot nose pokes across 18 plots within the same area. The amount of soil displaced and physical structure of foraging pits were examined from moulds of 47 fresh foraging pits. We estimated that an individual southern brown bandicoot could create ∼45 foraging pits per day, displacing ∼10.74 kg of soil, which extrapolates to ∼3.9 tonnes of soil each year. The digging activities of the southern brown bandicoots are likely to be a critical component of soil ecosystem processes.

Telling tails: Selective pressures acting on investment in lizard tails

Caudal autotomy is a common defense mechanism in lizards, where the animal may lose part or all of its tail to escape entrapment. Lizards show an immense variety in the degree of investment in a tail (i.e., length) across species, with tails of some species up to three or four times body length (snout-vent length [SVL]). Additionally, body size and form also vary dramatically, including variation in leg development and robustness and length of the body and tail. Autotomy is therefore likely to have fundamentally different effects on the overall body form and function in different species, which may be reflected directly in the incidence of lost/regenerating tails within populations or, over a longer period, in terms of relative tail length for different species. We recorded data (literature, museum specimens, field data) for relative tail length ( species) and the incidence of lost/regenerating tails ( species). We compared these (taking phylogeny into account) with intrinsic factors that have been proposed to influence selective pressures acting on caudal autotomy, including body form (robustness, body length, leg development, and tail specialization) and ecology (foraging behavior, physical and temporal niches), in an attempt to identify patterns that might reflect adaptive responses to these different factors. More gracile species have relatively longer tails (all 350 spp., ; also significant for five of the six families tested separately), as do longer (all species, ; Iguanidae, ; Lacertidae, ; Scindidae, ), climbing (all species, ), and diurnal (all species, ; Pygopodidae, ) species; geckos without specialized tails (); or active-foraging skinks (). We also found some relationships with the data for caudal autotomy, with more lost/regenerating tails for nocturnal lizards (all 246 spp., ; Scindidae, ), larger skinks (), climbing geckos (), or active-foraging iguanids (). The selective advantage of investing in a relatively longer tail may be due to locomotor mechanics, although the patterns observed are also largely consistent with predictions based on predation pressure.

Non-invasive monitoring of male and female numbat (Myrmecobius fasciatus: Myrmecobiidae) reproductive activity

The reproductive endocrinology of the highly endangered numbat (Myrmecobius fasciatus) is described for the first time. Patterns of faecal steroid secretion (progesterone [PM], oestradiol-17β [E2] and testosterone [TM] metabolites) were examined within a captive numbat population over 1 year and revealed a highly synchronized seasonal pattern of reproduction. TM secretion increased progressively from September to November, peaked in December and then decreased in February. All females displayed luteal phases (1-3), between late-November to late-March, in association with pregnant (Pr, n=4), non-productive mated oestrous cycles (NMEC, n=8) and non-mated oestrous cycles (NEC, n=6). The mean oestrous cycle length was 30.2 ± 1.1 d (n=11) and was comprised of a mean follicular (n=11) and luteal (n=18) phase length of 16.2 ± 1.6 d and 14.0 ± 0.8 d, respectively. No variation in mean luteal phase length or PM concentration according to cycle type (Pr, NMEC, NEC) or cycle number (1st, 2nd or 3rd cycle) was detected. Longitudinal profiling of PM secretion confirmed that the female numbat is seasonally polyoestrous and that the luteal phase occurs spontaneously. Changes in the secretion of E2 provided little instructive information on oestrous cycle activity. Mating success was 31%, with age and subject having no effect on mating success. Timing of introduction, of male to female, appeared to impact mating success, with paired animals introduced for a shorter time frame (≤14 d) prior to the first observed mating successfully producing young. Collectively, results of the present study confirm that PM and TM can be reliably used to index numbat reproductive activity.

Terrestrial mammals of the Gnangara Groundwater System, Western Australia: history, status, and the possible impacts of a drying climate.

Over the last 30 years declining rainfall and increased aquifer abstraction have heavily impacted water availability and ecosystems on the Gnangara Groundwater System (GGS). The mammal fauna of the area is considered to have been rich, with up to 28 terrestrial and 5 volant native species recorded since European settlement. This study investigated previous and current distribution of mammals on the GGS, and assessed potential impacts of predicted rainfall and groundwater declines on mammals. A general survey was conducted at 40 sites, and targeted trapping was undertaken for Hydromys chrysogaster and Isoodon obesulus fusciventer at wetlands. Nine native and seven introduced terrestrial mammal species were recorded during the general survey and capture rates were very low (1.05%). The most commonly captured native species was Tarsipes rostratus. There is evidence that only 11 (9 recorded and 2 considered to be extant) of the 28 historically recorded terrestrial native mammals still persist in the area. The species predicted to be most susceptible to rainfall and groundwater level declines include H. chrysogaster, I. obesulus fusciventer, and T. rostratus. Management and recovery actions required to protect mammals under predicted climatic changes include identification and maintenance of refugia and ecological linkages, supplementation of lakes, development of ecologically appropriate fire regimes, and control of predators.

Movers and Stayers: Novel Assemblages in Changing Environments

Increased attention to species movement in response to environmental change highlights the need to consider changes in species distributions and altered biological assemblages. Such changes are well known from paleoecological studies, but have accelerated with ongoing pervasive human influence. In addition to species that move, some species will stay put, leading to an array of novel interactions. Species show a variety of responses that can allow movement or persistence. Conservation and restoration actions have traditionally focused on maintaining or returning species in particular places, but increasingly also include interventions that facilitate movement. Approaches are required that incorporate the fluidity of biotic assemblages into the goals set and interventions deployed.

Does woodland condition influence the diversity and abundance of small mammal communities

Loss of mammal species in Australia in the last 200 years has been attributed to many factors including habitat removal and altered fire regimes. Decline in tree condition could contribute further to the ongoing decline of mammals. Eucalyptus wandoo trees are currently undergoing a decline in condition that can result in a loss of canopy and other changes to the habitat. This paper examines the relationships between E. wandoo tree condition, habitat characteristics and small mammal species richness and abundance. Live-capture trapping was conducted at 24 E. wandoo sites at Dryandra State Forest and Wandoo Conservation Park, Western Australia. Condition and microhabitat variables of E. wandoo were recorded for each site. Generalised additive mixed models revealed a range of habitat and tree condition characteristics that influenced small mammal abundance and species richness, including site litter cover, crown dieback, understorey vegetation cover and tree density. The availability of coarse woody debris played a large role in explaining the abundance of Cercartetus concinnus and Antechinus flavipes, along with other microhabitat and tree condition variables, such as tree leaf litter and crown dieback. Epicormic growth, crown density and the distance to the drift fence from E. wandoo trees were the common variables in the best model for the abundance of Sminthopsis griseoventer. The decline in condition of E. wandoo and the subsequent modifications to the microhabitat are correlated with changes in the small mammal community. A better understanding of how the decline of E. wandoo impacts small mammal communities could improve management practices in E. wandoo woodlands.