Zoology - Theses

Permanent URI for this collection

Search Results

Now showing 1 - 8 of 8
  • Item
    Thumbnail Image
    Predicting ectotherm life cycles under a variable climate: physiological diversity of matchstick grasshopper eggs and their ecological and evolutionary implications
    Kong, Jacinta Dara ( 2019)
    Understanding the processes underlying the phenology and distribution of species is a key problem in ecology. These relationships are important for predicting the responses to species to environmental change. Phenology and distribution are closely linked to climate and weather through the thermal dependence of life cycles. However, for many biodiverse taxa, like insects, we have a poor understanding of the mechanistic links between adaptive traits and how life cycles are adapted to seasonal and variable temperature patterns. Insect life cycles are synchronised with suitable climatic conditions at critical life stages, such as the egg stage. Variation in thermal sensitivity of development and dormancy are two mechanisms by which insects can generate adaptive life cycle phenotypes. Eggs, therefore, present a unique opportunity to link adaptive variation in traits with corresponding variation in life cycles and thermal environments to examine how life cycles are adapted to variable climates. To understand the adaptation of insect life cycles to variable climates, we require a mechanistic understanding of the interactions between adaptive developmental traits of eggs and variation in the thermal environment on adaptations. Our ability to test thermal adaptation in ectotherms is also limited by our ability to efficiently characterise thermal responses. In this thesis, I described how thermocyclers are an efficient means of characterising the thermal response of small ectotherms with enough precision and sample size. I then used the widely distributed, endemic and flightless Australian matchstick grasshopper genera Warramaba (Orthoptera: Morabidae) as a model system to examine the significance of variation in thermal responses at the egg stage for life cycles under a variable climate. I used a mechanistic modelling framework to tease apart developmental and environmental sources of variation in life cycles at the egg stage and simulate their consequences for phenology and distribution in the field. Matchstick grasshoppers showed remarkable diversity in developmental responses to temperature at the egg stage, primarily in the expression of dormancy. I found that diverse Warramaba life cycles are shaped by the interactions between such developmental variation and local environmental temperatures. I demonstrated that we can achieve a mechanistic understanding of life cycle adaptation by considering the evolution of temperature-dependent traits and the evolution of life history within the context of seasonal temperature cycles. Mechanistic models are powerful tools to investigate the sources of life cycle variation and their consequences for insect distribution and phenology. Such frameworks are directly transferrable to other socio-economically important or threatened species to understand how insects are adapted to local climatic conditions and predict responses to a changing climate.
  • Item
    Thumbnail Image
    Taxonomy, ecology and conservation genomics of North-Eastern Australian Earless Dragons (Agamidae: Tympanocryptis spp.)
    Chaplin, Kirilee ( 2018)
    Land clearing and modification of natural habitats is threatening biodiversity globally. In Australia, most native grassland habitats have been heavily modified for agriculture, including cropping and grazing. Grassland specialist species, including earless dragon lizards (Tympanocryptis spp.) in north-eastern Australia, are of conservation concern due to this continued habitat loss and fragmentation. However, the north-eastern Australian group of earless dragons (including the recently described T. condaminensis, T. wilsoni and T. pentalineata) are at significant risk, due to the presence of multiple undescribed cryptic Tympanocryptis lineages within this region. It is imperative that the taxonomy is resolved for these cryptic lineages of conservation concern, so conservation of these species may occur. One of the major challenges for taxonomists in recent times has been the species delimitation of morphologically cryptic taxa. The detection of distinct molecular lineages within cryptic genera has increased exponentially over the past decades with advances in genetic techniques. However, there are discrepancies in the rate and success of detection of cryptic taxa between studies using genetic methods and those using classic external morphology analyses. Therefore, novel integrative methods for species delimitation of cryptic taxa provide an avenue to incorporate multiple lines of evidence, including the application of osteological variation assessment where external morphological assessment fails to distinguish species. I develop a new pipeline integrating genomic data using single nucleotide polymorphisms (SNPs) and osteological geometric morphometric evidence from micro X-ray computed tomography (CT) imagery to assess variation between cryptic lineages for confident species delimitation. Here, I use this novel integrative pipeline to delimit cryptic lineages of earless dragons in north-eastern Australia. Prior to this study, there was evidence of three undescribed species of Tympanocryptis in this region. Using single mitochondrial and nuclear genes along with >8500 SNPs, I assess the evolutionary independence of the three target lineages and several closely related species. I then integrate these phylogenomic data with osteological cranial variation from CT imagery between lineages. I find that the very high levels of genomic differentiation between the three target lineages is also supported by significant osteological differences between lineages. By incorporating multiple lines of evidence for species delimitation, I provide strong support that the three cryptic lineages of Tympanocryptis in north-eastern Australia warrant taxonomic review. Earless dragons are found in most environments across the Australian continent, including a variety of ecological niches, from stony desert to tropical woodland or cracking clay savannah, although each species is often restricted to s certain habitat-type. I investigate the phylogenetic relationships among currently described earless dragons and newly delimited putative species with an assessment of broad biogeographic divisions, focussing on the north-eastern Australian Tympanocryptis group. I found significant structure across the north-eastern Australian lineages, with deep divergence between lineages occurring in the inland Great Artesian Basin region and more coastal Great Dividing Range. Regional diversification is estimated to have occurred in the late Miocene with subsequent Plio-Pleistocene speciations, and divergence and distributions of these species may therefore be reflective of the climate induced grassland-rainforest oscillations during this time. Based on these phylogenetic geographic relationships and the species delimitation from the integrative taxonomy approach, I describe three new species of Tympanocryptis from the cracking clay grasslands of the Darling Riverine Basin (T. darlingensis sp. nov.) and Queensland Central Highlands (T. hobsoni sp. nov.), and the stony open eucalypt woodlands on the Einasleigh Uplands (T. einasleighensis sp. nov.). The revision of these species provides further taxonomic clarity within the Tympanocryptis genus, and is an imperative step in the conservation of the north-eastern Australian earless dragons. These three putative Tympanocryptis species and the other three recently described earless dragons in north-eastern Australia inhabit restricted niches and areas with varying levels of habitat fragmentation and modification, and are therefore of significant conservation concern. However, little is known about these six north-eastern Australian earless dragon species. I utilise genomic methods to investigate population connectivity and genetic structure to determine management units. I then use species distribution modelling (SDM) to assess habitat suitability and fragmentation of each species. I integrate results of these analyses to form conclusions on the distribution and population structure of these earless dragons. I then discuss the major threatening processes and potential conservation strategies. This thesis uses several integrative approaches in resolving the taxonomy and forming conclusions on the conservation management of the north-eastern Australian Tympanocryptis species. This study successfully delimits cryptic lineages, explores the phylogenetic and geographic relationships between species, and provides baseline population genomics and ecological data to be used for conservation assessments and management decisions of earless dragons in north-eastern Australia.
  • Item
    Thumbnail Image
    Triple jeopardy in the tropics: assessing extinction risk in Australia's freshwater biodiversity hotspot
    Le Feuvre, Matthew Charles ( 2017)
    Freshwaters are the most degraded and imperiled ecosystem globally. Despite this high vulnerability, conservation efforts in freshwaters often lag behind those in terrestrial and marine ecosystems. In Australia this is particularly evident; despite high levels of river degradation, few freshwater fishes have had their conservation status assessed and only 14% of fishes are listed. Most listed species are restricted to southern Australia where rivers are particularly degraded. Northern Australia’s rivers are very diverse with many highly range restricted fishes. Yet almost no species are listed, despite potential vulnerability and an increasing number of threats across the north. Nowhere is this more evident than the Kimberley region in the north-west, where 49% of species are restricted to three or fewer rivers, and 10% are restricted to an area of <20 km2. Very little is known about the ecology of the region’s endemic fishes, so their vulnerability cannot be assessed. In my thesis I assess extinction risk in the freshwater fishes of the Kimberley using the triple jeopardy framework, that is whether they have small geographic ranges, low abundances and/or narrow ecological niches. Specifically I aim to (1) determine the relationships between range size, body size and abundance in all Australian freshwater fishes and (2) whether these relationships can be used to identify species at risk of extinction. I then determine whether (3) small ranged Kimberley endemics have narrow habitat, dietary or thermal niches compared to closely related widespread species and (4) synthesize these results to identify the fishes most at risk of extinction in the Kimberley. First, I test for a relationship between geographic range size and body size in all Australian freshwater fishes. I then investigate how this relationship varies with conservation status. I identify currently unlisted freshwater fishes that share traits with listed species and map their distribution, along with freshwater fish research effort, across Australia. I found a positive relationship between range size and body size. For a given body size, conservation listed species have a range less than one tenth the size of unlisted species. Based on this relationship, I identified 55 additional species that may be vulnerable to extinction. Most of these species are restricted to northern Australia where freshwater fishes are poorly known due to low research effort. Second, I test for abundance-geographic range size and abundance-body size relationships in Australian freshwater fishes and investigate how these relationships vary with conservation status. I identify and map currently unlisted freshwater fishes that are numerically rare, and combined with the results outlined above, map species with a double jeopardy risk of extinction. I found a negative body size-abundance relationship and no correlation between range size and abundance. Although relative abundance was a poor predictor of current conservation listing, I identified 59 consistently rare species. Twenty of these species (34%) currently suffer a double jeopardy risk of extinction and all were restricted to northern Australia. Third, using closely related widespread and endemic congeneric pairings of Kimberley freshwater fishes, I investigate whether endemic species have narrow dietary niches at any stage during their development. Using qualitative measures of habitat and presence/absence data, I also assess habitat specialization. Most range-restricted species have narrower ecological niches making them more vulnerable to extinction. Fourth I test the thermal performance of two pairs of congeneric species that are sympatric in the Drysdale River, with one widely distributed species and one range restricted species in each pair. In the Syncomistes pair, resting metabolic rate (RMR) was similar between species at low temperature but at higher temperatures the RMR of the widespread species was lower due to the onset of anaerobiosis. The range-restricted Syncomistes also has a higher critical thermal limit (CTL). In the Melanotaenia pair, the results were the opposite, with the widespread species having a higher CTL and RMR. The thermal performance of each species was related to their distribution within the catchment rather than their geographic range size, with the thermally sensitive species dominating the cooler, perennial downstream reaches, and the hardier species being more abundant in the hotter, more ephemeral upper catchment. Finally, I use the above information to assess the triple jeopardy extinction risk in the fishes of the Kimberley. Seventy-nine per cent of Kimberley endemic fishes are vulnerable on one or more axis, and two species had a triple jeopardy risk of extinction. The majority of vulnerable species are found in the remote rivers of the north-western Kimberley, but the most imperiled species (Hypseleotris kimberleyensis) is restricted to the heavily degraded Fitzroy River. My thesis shows that, despite fundamentally different environments, life histories and dispersal capacity, Australian freshwater fishes exhibit range size, body size and abundance relationships largely similar to terrestrial fauna. By identifying northern Australia as a hotspot of unrecognized vulnerable species, I provide an important context for guiding targeted research and informing future conservation management of Australia’s freshwater fishes. Combined with their small ranges and/or low abundance, the narrower niches of most Kimberley endemic species makes the region’s fishes particularly extinction prone. By identifying which endemic species are most vulnerable, my study provides specific information for targeting conservation efforts in the region. As the Kimberley and northern Australia more broadly are earmarked for major development, substantial effort is needed to effectively manage fish populations, design and manage developments with the environment as a major stakeholder and preserve remote rivers with high endemism and extinction risk. However, as northern Australia’s rivers are in good condition, with planning and research there is an excellent opportunity for proactive, properly informed freshwater conservation across the region.
  • Item
    Thumbnail Image
    Competition and coexistence: the ecology of sympatric common and mountain brushtail possums (Trichosurus spp.)
    Gloury, April Maree ( 2014)
    Closely related species often possess similar ecology due to their shared phylogenetic history, and consequently they usually require similar resources. As a result, potential for competition between closely related species is high. Without the rapid renewal of shared resources, coexistence between such species can usually only occur in the presence of resource partitioning. I studied the ecology of sympatric common and mountain brushtail possums (Trichosurus vulpecula and T. cunninghami) within a network of linear forest remnants in Boho South, north-east Victoria, with the aim of uncovering the processes facilitating coexistence between these congeneric species. Both common and mountain brushtails are primarily folivorous, arboreal/semi-arboreal marsupials, and occur sympatrically through some parts of their distributions. I examined three-dimensional resource partitioning by the foraging guild of arboreal marsupial folivores to which the two brushtail species belong. At Boho South, this guild included the koala, the greater glider and the common ringtail possum, in addition to the two brushtail species. I found that significant resource partitioning occurred in both the horizontal and vertical plane, with each species adopting a particular foraging niche with regard to tree species use and the available vegetation strata. Vertical stratification of such a diverse marsupial guild has not previously been demonstrated in temperate forest systems, and this result highlights the role of habitat heterogeneity in maintaining diverse faunal assemblages. I radio-tracked pairs of adult female common and mountain brushtails occurring in close sympatry in the linear forest remnants. Female mountain brushtails maintained home range areas more than twice the size of those of common brushtails, and the home ranges of mountain brushtails overlapped those of sympatric common brushtails more significantly than the reverse. Although the degree of total (95 %) home range overlap was high, the core (50 %) home ranges of study pairs overlapped significantly less. Patterns of den use between the two species were similar, with common and mountain brushtails using a mean of 6.0 ± 1.1 and 5.7 ± 1.4 dens per individual, respectively, over a mean of 15.5 months monitored per individual. The majority of den fixes were in tree hollows (75.7 % and 89.5 % of common and mountain brushtail den fixes, respectively). Vertical vegetation strata were used differently by each species, with common brushtail using the canopy and midstorey significantly more, and the understorey and ground layer significantly less, than mountain brushtails. The maintenance of relatively discrete core home range areas combined with fine-scale differences in use of tree species and vegetation strata appeared to facilitate the high degree of home range overlap between adult females. I conducted an extensive analysis of the diet of each species, examining faecal samples for both plant and fungal content. Dietary resources were strongly partitioned between the two brushtail species: common brushtails foraged primarily on Eucalyptus, while mountain brushtails foraged primarily on silver wattle. Common brushtails also consumed significantly more mistletoe foliage. Both species used fungal and floral food resources, however, these were also strongly partitioned between the two species: common brushtails supplemented their diet more often with flowers, while mountain brushtails consumed a greater amount and diversity of epigeal and sequesterate fungal taxa. Given the tripartite relationship occurring between sequesterate ectomycorrhizal fungi, the forest tree and shrub taxa with which the fungi form symbiotic relationships, and the mycophagous mammals that disperse fungal spores in their faeces, the consumption of sequesterate fungi by mountain brushtails is likely to play an important role in ecosystem health at Boho South, particularly given the local extinction of specialist fungivores, the potoroids, in this area. I propose that the strong partitioning of foliage between the two brushtail species, combined with an abundance of shelter resources in the form of suitable tree hollows, facilitates the stable coexistence of common and mountain brushtails at Boho South. By significantly reducing competition for food resources, dietary partitioning appears to allow each species to maintain home ranges that overlap strongly with those of their congeners. As the foraging niches of each brushtail species are consistent with other research on their digestive tolerances, I suggest that the divergent diets of common and mountain brushtails are a result of ecological character displacement having evolved in the two species to minimise competition for food resources. Current fine-scale partitioning of habitat components and supplementary food sources by common and mountain brushtails at Boho South are a possible further means by which these two species avoid competition for resources.
  • Item
    Thumbnail Image
    Sampling the social environment in an uncertain world
    Heap, Stephen Michael ( 2012)
    The world that we inhabit is characterised by variation in the environment over space and time. Subsequently, animals are faced by uncertainty regarding their current and future conditions. Thus, it is critical to understand the nature of responses to uncertainty. Theory suggests that animals incorporate information from their environment through natural selection or personal experience, and use this information to make decisions that anticipate environmental conditions. Animals also possess the ability to improve their estimation of current conditions by sampling for new information, and individuals that incorporate updated information can have an adaptive advantage over those that use older information. However, sampling can be costly and selected against. The use of sampling strategies can also depend on social interactions within a population, the structure of the landscape, and variation in spatial scale. This thesis considers the conditions in which it is adaptive for an individual to sample information from their social environment, and how this behaviour is affected by the landscape and the decisions being made by others. In particular, I explore the use of updated information from the social environment in three contexts in which fitness is dependent on the social environment and phenomena attached to the landscape. In Part I, I report the results of a field experiment on breeding site selection in the terrestrial toadlet Pseudophryne bibronii. I collected every calling male in a breeding population, released them into empty habitat patches, and observed the decisions that they made during re-settlement. I found that the decision to sample social cues when selecting breeding sites reflected a predicted relationship between the value of previously gathered information and spatial scale. In Part II, I conceptually explore the interaction between conspicuous features of the landscape, or landmarks, and the adaptive value of sampling the social environment by conducting a literature review on the adoption of landmarks for territorial boundaries. Additonally, I conducted a laboratory experiment on the ability for convict cichlids, Amatitlania nigrofasciata, to learn spatial associations between landmarks and contests. The results of these studies indicate that the effect of landmarks on sampling may depend on the process responsible for the adoption of a landmarked boundary and the landmark’s reliability for estimating location. Finally, in Part III, I consider the value of sampling during dyadic interactions between individuals. I measured how individual P. bibronii changed their calling behaviour in response to a persistent intruder simulated by a playback device, and reveal that males adjust their behaviour as they gather additional information. Additionally, I analyse a game-theoretic model that considers the functional significance of sampling during contests, which suggests individuals face a trade-off between improving their assessment of opponents and having the capacity to fight for access to fitness-enhancing resources. Furthermore, there can be conflicts over the transfer of information that affect the evolution of sampling. Overall, I conclude that the value of sampling information from the social environment can depend on spatial scale, landmarks and the social interactions within populations. These conclusions may help develop an ecological understanding of how individuals use information.
  • Item
    Thumbnail Image
    A predictive framework to assess response of invasive invertebrates to climate change: pest mite species of Australian grains
    Hill, Matthew Peter ( 2012)
    Climate change is set to place enormous pressure on both biodiversity and agricultural production. Important vectors of agricultural damage, such as pest invertebrates, are likely to respond to climate change in different ways. Differing pest invertebrate responses in grain crops will translate to shifts in outbreak frequency and persistence of pests, changes to pest species assemblages, and alter biocontrol by natural enemies. Successful management will thus require predictions of how climate change will affect individual species in terms of distributions and abundance. Climate change predictions for species are often based on models that characterize distributions though species-environment relationships. However, there are important factors relating to the ecology and evolutionary biology of species that are not incorporated and will mediate climate change response. This thesis aims to establish a transferrable framework, employing multiple, complimentary lines of enquiry, to build on distribution models and understand how climate change may affect different crop pests. I focus on two important mite species groups, the blue oat mites (Penthaleus spp.) and the redlegged earth mite (Halotydeus destructor). These mite species are invasive, and so understanding how they have adapted since being introduced into Australia will help predict response to climate change in the future. The first part of this thesis applies environmental niche models to distribution data of the three cryptic Penthaleus species, to make preliminary assessments of response to climate change. These models found that the distributions of each species are governed by different climate variables, and that species assemblages are likely to shift under climate change. The remainder of the thesis builds on such models by applying a more integrated approach to assess climate change response of H. destructor. This species provides an ideal candidate to develop this framework as the biology and ecology is well understood, and its introduction and spread in Australia has been well documented.
  • Item
    Thumbnail Image
    Fertility control of common brushtail possums, Trichosurus vulpecula, in free-ranging populations
    Subair, Muhammath Siyam ( 2011)
    The common brushtail possum, Trichosurus vulpecula, is a serious ecological and agricultural pest in New Zealand, where it was introduced, and is very abundant in many Australian cities. Management of overabundant native species is contentious, with wildlife managers increasingly using fertility control as a humane option. My study developed three DNA vaccines based on coat protein 4 (CP4) and vesicle associated protein 1 (VAP1), previously shown to reduce fertility by ca 40% for a mean period of 1.4 years and 1.5 years respectively. CP4 and VAP1 cDNA were amplified by PCR, separately cloned into pcDNA3.1 plasmid vector, transformed into Escherichia coli, confirmed by sequencing, purified from endotoxins, and verified by in vitro expression in mammalian cells before use. The DNA vaccines were pcDNA3.1-CP4, pcDNA3.1-VAP1, a combined vaccine of the two (pcDNA3.1-CP4 + pcDNA3.1-VAP1), and a control vaccine (pcDNA3.1 blank plasmid). The effect of vaccines on animal behaviour was tested both on captive and free-ranging possums. Compared to controls, immunization with CP4 or the combined vaccine resulted in significant behavioural changes related to social rank and number of dens used in captivity and home range areas, long-range movements and den types used in the wild. The combined vaccine, the most effective vaccine, caused the highest degree of changes, while VAP1, the weakest contraceptive produced the lowest degree of changes. The social rank increased significantly in pcDNA3.1-CP4 and combined vaccine-immunized possums compared to controls. However, the dominance behaviour was positively correlated with weight gain. The absence of weight gain in wild females in my study after treatment means that dominance patterns in free-ranging possums are unlikely to change as a result of this factor after vaccination. Similarly, while immunized females used a higher number of dens compared to controls in captivity, the number of dens used by free-ranging females did not change between groups following treatment. Both pcDNA3.1-CP4 and combined vaccine-immunized females undertook significantly higher proportion of long-range movements and had a larger home range area compared to controls. These movements were associated with the absence of dependent young. No evidence of dispersal or mortalities was found.
  • Item
    Thumbnail Image
    The distribution and ecology of ants in vineyards
    Chong, C.-S. ( 2009)
    Ants are highly abundant and ubiquitous in many terrestrial ecosystems. They perform many important ecological functions and have been widely employed as bioindicators for various terrestrial monitoring programmes. In agroecosystems, their role is controversial because ants can act as predators against herbivorous pest but also associate with and protect honeydew-producing hemipteran pests. The ecology, function and interactions of ants with other arthropods in vineyards are poorly known and this thesis therefore examines their distribution and ecology in south-eastern Australian vineyards. An extensive survey of 50 vineyards distributed in five regions in South Australia and Victoria recorded 147 native ant species and one invasive species, Linepithema humile (Mayr). Species richness, compositional similarities and assemblage structure varied within and across regions. High species turnover and variation in assemblage structure were found across regions and implications of these patterns are discussed. The invasive L. humile was only detected in some vineyards in one region. The potential impact of management practices and off-farm vegetation on augmenting ant diversity and conserving biodiversity are considered. The impact of non-target agrochemical applications on ants was investigated in 19 vineyards that received varying levels of agrochemical input. Ant assemblage structure and assemblages were not found to be impacted by pesticides. In contrast, ant assemblage structure was influenced by the presence of shelterbelts near the sampling area. Reasons for the resilience of ants to pesticides are given and assessment at the colony level instead of worker abundance is suggested. An ant-exclusion experiment was designed to test the impact of native ants on both canopy and ground arthropods concurrently. The potential influence of ants on predation and parasitism on eggs of light brown apple moth (LBAM), a grape pest, was also examined. Adult grapevine scale insects and earwigs under bark were also counted after a season of ant-exclusion. While ant exclusion was successful, there was no detectable difference in the abundance of most arthropod orders and feeding groups between ant-excluded and control vines, although ground spiders were more abundant under ant-excluded vines, despite increased ground ant foraging pressure. LBAM egg parasitism and predation were low and probably affected by weather and other arthropods. Ant exclusion did not reduce survival of scale insects, although the distribution and abundance of scale insects were negatively associated with earwigs. Reasons for the lack of negative effects of ants are discussed. The spatial patterns of ants were investigated with intensive pitfall trappings in two vineyards to examine if non-random patterns occur and whether these might be the result of competitive species interactions as well as non-crop vegetation adjacent to the vineyards. Null model analyses suggested competitive species interactions within ant assemblages that might have been driven by dominant species even though both positive and negative associations between dominants were also found. Consistent spatial aggregations indicated significant spatial overlap in distributions of some species. Such overlap suggests that potential co-existence might be attributed to temporal partitioning or differences in foraging strategies. The presence of vegetation had a marked influence on ant assemblage structure and competitive interactions, and might also facilitate co-existence by increasing resource heterogeneity. The implications of these findings for sampling strategies and ecological processes within vineyards are discussed. This thesis has provided new information about ants in vineyards. The high ant diversity could be important in maintaining ecosystem services. Among the 33 ant genera recorded, Iridomyrmex, Paratrechina and Rhytidoponera have the greatest potential in contributing to canopy pest suppression although their associations with honeydew-producing hemipterans need to be considered. Stable isotope analysis or/and molecular gut content analysis should reveal their trophic position in vineyards. Evaluation of crop yield that is directly attributed to soil conditioning by ants in agroecosystems should be explored. The importance of landscape composition, complexity and connectivity is highlighted and role of agroecosystems in conserving biodiversity is emphasised. Future research should be directed towards understanding how landscape composition and complexity may enhance ant diversity and alter dynamics and interactions that may be functionally important (biological control, soil conditioning, etc) in a landscape context.