Impact of removal on occupancy patterns of the invasive rainbow lorikeet (Trichoglossus moluccanus) in Tasmania

Introduced species may threaten both biodiversity and agriculture, necessitating an understanding on the factors that influence their distribution, and the efficacy of control measures. In Tasmania, Australia, the introduced rainbow lorikeet (Trichoglossus moluccanus) may be widespread, but data on where they occur and the efficacy of control methods are limited. We used an occupancy modelling framework (presence–absence data) to undertake a survey of two populations of invasive rainbow lorikeets to: (i) understand their distribution across the north and south of the island, and (ii) evaluate the impact of removing birds from the southern population by quantifying occupancy before (2016) and after (2018) removal. The best model explaining occupancy in both populations included a negative relationship with distance from central urban areas. We found no change in site occupancy or detectability in the southern population after removal of 208 birds (potentially comprising >50% of their original population size). This result may be explained by one of three possibilities: (i) the population is larger than previously thought, (ii) the population recovered quickly after reduction, or (iii) removal of birds reduced population density but not area of occupancy. We highlight the importance of urban habitats for the invasive rainbow lorikeet and suggest that alternative methods (e.g. abundance/density-based monitoring) may better detect impacts of removal.     

The effects of burning on the understorey composition of 11–13 year-old rehabilitated bauxite mines in Western Australia – Vegetation characteristics

Alcoa of Australia Limited has been rehabilitating bauxite mines in the jarrah (Eucalyptus marginata) forest of Western Australia for more than 30 years. Mines rehabilitated in the early 1980s using out-dated methods have built up substantial fuel loads that may be reduced through prescribed burning. The vegetation response of 11–13 year-old rehabilitated bauxite mines to fire regimes differing in intensity and season over the first two years of post-burn succession is compared to the native jarrah forest. A total of 243 species from 137 genera and 56 families were identified in the native forest reference sites and in the 11–13 year-old rehabilitated areas before and after burning. The vegetation of the pre-burn rehabilitated areas was very different to that of the native jarrah forest. While total live plant cover, Acacia density, non-native eucalypt seedling density, weed density and the evenness index were similar between the two areas, total plant density, live Acacia cover, the proportion of weeds, native species numbers and diversity were significantly different. However, the greatest difference between the vegetation of the pre-burn rehabilitated sites and the native jarrah forest was the higher dominance of seeding species (plants killed by fire) in rehabilitated areas. In contrast, native jarrah forest was dominated by resprouting species (plants that survive fire). Burning the rehabilitated sites was successful in making the areas more similar to the forest in terms of total plant density, live Acacia cover and native species numbers but decreased their similarity in terms of live plant cover, Acacia density, non-native eucalypt seedling density, weed density and evenness. The vegetation response of the rehabilitated areas to different seasons of burning showed that autumn burning led to a greater increase in plant establishment than spring burning. Autumn burning also resulted in an undesirable increase in the density of non-native eucalypt seedlings that was not observed following spring burning. Although burning these 11–13 year-old rehabilitated sites will increase similarity to the native forest, it is unlikely that they will resemble the native jarrah forest without further management intervention.     

Habitat use by Nonnative Rainbow Trout, Oncorhynchus mykiss, and Native Little Colorado spinedace, Lepidomeda vittata

We evaluated overlap in microhabitat use between nonnative rainbow trout, Oncorhynchus mykiss, and native Little Colorado spinedace, Lepidomeda vittata, a federally threatened cyprinid, in natural and experimental settings. In natural settings, we also examined occurrence and microhabitat use of two other native fishes, speckled dace, Rhinichthys osculus, and bluehead sucker, Catostomus discobolus. Native species co-occurred, as did rainbow trout and bluehead sucker. However, occurrences of Little Colorado spinedace and speckled dace were not significantly correlated with occurrence of rainbow trout. Total lengths of all three native species were significantly smaller at allopatric sites than at sites sympatric with rainbow trout. Microhabitat characteristics at sites with rainbow trout did not differ from those where the other three species were found, but did differ among the native species. In laboratory experiments with Little Colorado spinedace and rainbow trout, rainbow trout used the lower depth zone most, and spinedace increased use of the lower depth zone upon addition of rainbow trout. In addition, species tended to co-occur in zones, but used cover independently of one-another, suggesting a low level of agonistic interactions. However, after addition of a high density of rainbow trout, spinedace tended to use cover less than before. We suggest that the species can coexist at low rainbow trout densities. Potential negative effects of rainbow trout on Little Colorado spinedace likely increase with increasing densities of rainbow trout, and rainbow trout likely affect smaller size classes of Little Colorado spinedace more than larger ones.     

Seed Removal and Predation as Factors Affecting Seed Availability of Tree Species in Degraded Habitats and Restoration Plantings in Rainforest Areas of Queensland,Australia

The post‐dispersal removal or predation of seeds of native tree species was investigated in Queensland, Australia, at degraded habitats and rainforest restoration sites where direct seeding might be used to facilitate tree regeneration (old fields or open habitats, lantana thicket, rainforest edge, and 5‐ and 10‐year‐old restoration plantings). Seed removal/predation was assessed in relation to tree seed weight and canopy density of the habitats during the wet season period. Results indicated that seed removal/predation imposes limitations on seed availability, particularly for small seeded species. In most situations, larger seeds were less removed/predated, most likely due to the more limited range of large seed consumers. The use of large, hard‐coated seeds may potentially reduce seed loss in open situations (from both seed removal and desiccation), unless large seed consumers frequent the site. Canopy cover exerted an influence on seed removal/predation, though trends varied in relation to site and the time of season. Broadcast sowing of seed under planted tree canopies at the more advanced stages of closure may in some areas result in higher seed removal/predation. Likewise, seeding in areas dominated by woody weeds may result in high seed losses to consumers such as rodents. Results suggested that undertaking direct seeding to coincide with the maximal period of fruit production may in some situations be beneficial to minimize seed loss. Overall, site context, canopy cover, and species selection appear to be important considerations when aiming to reduce loss of seeds to animal seed consumers in restoration work.     

Is fencing enough? The short‐term effects of stock exclusion in remnant grassy woodlands in southern NSW

Summary Fencing remnant native vegetation has become a widespread activity for arresting declines in biodiversity in agricultural landscapes. However, few data are available on the effectiveness of this approach. The present study investigated the short-term effects of fencing to exclude livestock on dominant tree and shrub recruitment, plant species cover, litter and soil characteristics in remnant grassy woodlands in southern NSW. Vegetation and soil surveys were undertaken at 47 sites fenced by Greening Australia (NSW) for 2–4 years. Fenced and unfenced areas at each site were compared using split-plot sampling. Woodlands sampled were dominated by Yellow Box/Blakely's Red Gum ( Eucalyptus melliodora/Eucalyptus blakelyi ), Grey Box ( Eucalyptus microcarpa ) or White Cypress-pine ( Callitris glaucophylla ). Significantly higher numbers of tree recruits were found in the fenced sites, with tree recruitment found in 59% of fenced sites compared with 13% of unfenced sites. Fenced sites also had significantly greater cover of native perennial grasses, less cover of exotic annual species and less soil surface compaction. However, outcomes varied among woodland ecosystems and individual sites. Where tree recruitment occurred, there was significantly more tree recruitment where there was greater perennial grass cover and less regeneration where exotic annual grass cover or overstorey crown cover was dense. Few shrubs recruited in fenced or unfenced areas, reflecting the lack of mature shrubs in most sites. Fencing is an important first step for conserving threatened grassy woodlands, but more active management may be needed to enhance woodland recovery, particularly in sites where few or no recruits were found.
Key words bush regeneration, fencing, grazing exclusion, rehabilitation, woodland restoration.     

Effect of dilution degree of commercial nectar and provision of fruit on food,energy and nutrient intake in two rainbow lorikeet subspecies

A feeding trial was performed on adult rainbow lorikeets of two subspecies: six green-naped lorikeets (Trichoglossus haematodus haematodus) and six red-breasted lorikeets (T. haematodus mitchellii). Throughout the entire trial, half of the birds from each subspecies had ad libitum access to water-diluted commercial nectar powder and drinking water only, whereas the other half also received ad libitum apple pieces. During three consecutive 14-d periods, the nectar powder was diluted to a different degree: 1:3 (low), 1:5 (high) and 1:4 (medium) (v:v). Diluting nectar to a higher degree resulted in both subspecies in a decrease in voluntary energy intake. Next, nectar intake significantly decreased when apple was available and apple intake significantly increased when fed higher-diluted nectar. In green-naped lorikeets fed nectar and apple, energy intake was similar between dilution degrees of nectar but was lower compared with feeding only low- or medium-diluted nectar. Whereas, in red-breasted lorikeets, provision of apple next to medium- or high-diluted nectar resulted in higher voluntary energy intake compared with feeding solely nectar of any degree. Overall, protein and thiamine intake as well as Ca:P ratio of the ingested ration were lowest when fed highly diluted nectar and apple. Yet, minimal requirements were still covered. Because energy content of fruit can be higher than liquid diets, in this case medium- or high-diluted nectar, ad libitum provision of fruit as a means to lower voluntary energy intake in lorikeets, for instance in case of obesity, needs to be considered with care. Zoo Biol 28:98–106, 2009. © 2009 Wiley-Liss, Inc.     

Post-fire regeneration strategies and tree bark resistance to heating in frequently burning tropical savanna woodlands and grasslands in Ethiopia

Regeneration mechanisms of vegetation and the role of tree bark resistance to frequent fire were studied in savanna woodlands and grasslands in Gambella, Western Ethiopia. Data were collected from four sites, each with three replicate plots. The variation between sites in species composition and biomass correlated with the differences in fire intensity. Foliar cover was recorded for individual plant species regenerating by sprouting from older parts of plants that had survived fire or by seedlings; records were made during the dry season and at the beginning of the wet season. Data on bark thickness and tree diameters of 12 dominant tree species were also recorded. Both facultative and obligate sprouters significantly contributed to post‐fire recovery, comprising 98.5 % of total vegetation cover. The contribution of seedlings to cover and abundance immediately following fire was negligible, but seedling density increased in the beginning of the rainy season, 4 to 5 months after fire. The importance of the sprouting and seeding strategies varied between the different plant growth forms. The highest contribution to cover and frequency was made by the most abundant grass species, which reproduced in both ways. Facultative sprouters made up 67.3 % of the vegetation cover, out of which 54 % consisted of grasses. Broad‐leaved herbs and trees/shrubs regenerating mainly by sprouting made up 31.3 % of the vegetation cover. Adaptations to fire in tree species seemed to include the development of a thick bark, once the tree has passed seedling stages. Tree bark thickness and tree diameter at breast height were strongly correlated with the time taken for cambium to reach an assumed lethal temperature of 60°C when exposed to fire, which indicated that mature trees with thick barks might resist stronger fire better than, e.g., small or young trees and trees with thin bark. However, for a given bark thickness the cambium resistance to heat varied three‐fold among species. Hence, site differences in fire intensity seemed to influence the distribution of trees depending on their bark characteristics and resistance to fire.     

Variation in exotic and native seed arrival and recruitment of bird dispersed species in subtropical forest restoration and regrowth

Invasive bird-dispersed plants often share the same suite of dispersers as co-occurring native species, resulting in a complex management issue. Integrated management strategies could incorporate manipulation of dispersal or establishment processes. To improve our understanding of these processes, we quantified seed rain, recruit and seed bank density, and species richness for bird-dispersed invasive and native species in three early successional subtropical habitats in eastern Australia: tree regrowth, shrub regrowth and native restoration plantings. We investigated the effects of environmental factors (leaf area index (LAI), distance to edge, herbaceous ground cover and distance to nearest neighbour) on seed rain, seed bank and recruit abundance. Propagule availability was not always a good predictor of recruitment. For instance, although native tree seed rain density was similar, and species richness was higher, in native plantings, compared with tree regrowth, recruit density and species richness were lower. Native plantings also received lower densities of invasive tree seed rain than did tree regrowth habitats, but supported a similar density of invasive tree recruits. Invasive shrub seed rain was recorded in highest densities in shrub regrowth sites, but recruit density was similar between habitats. We discuss the role of microsite characteristics in influencing post-dispersal processes and recruit composition, and suggest ways of manipulating these processes as part of an integrated management strategy for bird-dispersed weeds in natural areas.     

Housing Shortages in Urban Regions: Aggressive Interactions at Tree Hollows in Forest Remnants

Urbanisation typically results in a reduction of hollow-bearing trees and an increase in the density of particularly species, potentially resulting in an increased level of competition as cavity-nesting species compete for a limited resource. To improve understanding of hollow usage between urban cavity-nesting species in Australia, particularly parrots, we investigated how the hollow-using assemblage, visitation rate, diversity and number of interactions varied between hollows within urban remnant forest and continuous forest. Motion-activated video cameras were installed, via roped access to the canopy, and hollow usage was monitored at 61 hollows over a two-year period. Tree hollows within urban remnants had a significantly different assemblage of visitors to those in continuous forest as well as a higher rate of visitation than hollows within continuous forest, with the rainbow lorikeet making significantly more visitations than any other taxa. Hollows within urban remnants were characterised by significantly higher usage rates and significantly more aggressive interactions than hollows within continuous forest, with parrots responsible for almost all interactions. Within urban remnants, high rates of hollow visitation and both interspecific and intraspecific interactions observed at tree hollows suggest the number of available optimal hollows may be limiting. Understanding the usage of urban remnant hollows by wildlife, as well as the role of parrots as a potential flagship for the conservation of tree-hollows, is vital to prevent a decrease in the diversity of urban fauna, particularly as other less competitive species risk being outcompeted by abundant native species.     

Transient persistence of bobcat (Lynx rufus) occurrence throughout a human-dominated landscape

Human developments have detrimental effects on wildlife populations globally with carnivores being particularly sensitive. The bobcat (Lynx rufus) is often considered an adaptable mesocarnivore that occurs throughout varied landcover types within its wide distribution and may be less susceptible to the negative effects of development. Our objectives were to investigate the landscape occupancy dynamics of bobcats in a highly developed and densely populated region of the northeastern United States to evaluate the sensitivity of bobcat occurrence to natural and anthropogenic landscape features. We established a large-scale camera trapping survey throughout Rhode Island, USA, sampling from 2018 to 2020. Using dynamic occupancy models, we found initial site occupancy was positively influenced by the amount of forested wetland habitat, while increasing road density and shrub cover negatively influenced the probability of site colonization. Surprisingly, we found no hypothesized variables to influence site-level extirpation probability, or any seasonal effects on dynamic parameters. Lastly, we found that forest cover and road density negatively influenced the probability of detection. The probability of occupancy was high, >0.8, throughout much of the study area (49%), but we also found relatively high site transients, with the probability a site would change occurrence status from season to season at ≈0.27 in the majority of the study area (70%). Our results show that although bobcats can persist in human-dominated landscapes, they require contiguous natural areas to do so. Future expansion of road infrastructure may reduce habitat connectivity and increase road mortalities, thus jeopardizing the population.     

Seeking parsimony in landscape metrics

Numerous metrics describing landscape patterns have been used to explain landscape-scale habitat selection by birds. The myriad metrics, their complexity, and inconsistent responses to them by birds have led to a lack of clear recommendations for managing land for desired species. The amount of a target land cover type in the landscape (percentage cover) often has been a useful indicator of the likelihood of species occurrence or of habitat selection; is it also a more adequate and parsimonious measure for explaining species distributions than patch size or more complex measures of landscape configuration? We examined responses of 6 woodland-interior bird species to the percentage tree cover within prescribed areas and to patch size, edge density, and other metrics. We examined responses in 2 landscapes: a mixed woodland-savanna and an eastern deciduous forest. For these 6 species, percentage tree cover explained bird occurrence as well as or better than other measures in both study areas. We then repeated the analysis on a larger group of woodland species, including those associated with woodland edges. The bird species we studied had varied responses to landscape metrics, but percentage tree cover was the strongest explanatory variable overall. Although percentage cover estimated from remotely sensed data is an inexact representation of habitat in the landscape, it does appear to be reliable and easy to conceptualize, relative to other measures. We suggest that, at least for woodland habitat, percentage cover is a broadly useful measure that can be helpful in pragmatic questions of explaining responses to landscapes or in anticipating responses to landscape change. © 2011 The Wildlife Society.     

Microbats in a ‘leafy’ urban landscape: are they persisting,and what factors influence their presence?

Urbanization is an extreme form of habitat modification, but retention of native vegetation in bushland reserves may improve the ecological sustainability of cities. We focused on bats (Microchiroptera) and investigated the use of the urban matrix and surrounding bushland in a region of Sydney, Australia, where remnant bushland persists and gardens often support large trees. Ultrasonic surveys were conducted at 40 sites over one summer season in the backyard matrix, bushland remnants and surrounding National Parks to determine which species were present, and the influence of landscape elements and habitat characteristics on activity, species richness and presence of individual species. In total, 15 of the 17 microbat species known from the Sydney region were recorded in the study area. Yet only three of these species, Chalinolobus gouldii, Mormopterus species 2 and Miniopterus schreibersii were present in more than 40% of sites. Bat activity was significantly higher in remnant bushland on shale soils and in backyards, compared with sandstone gully and ridge remnants, or reference sites in nearby National Parks. Furthermore, species assemblages in urban areas were different from assemblages in reference sites. Of all the habitat characteristics examined, the amount of bushland within 0.5–3 km surrounding a site and tree density were the most common predictors of individual species presence, particularly rare species. Area of bushland, hollow abundance and average tree diameter were positively correlated with species richness, while tree diameter was the strongest predictor of total microbat activity. The proximity of large areas of bushland and the many trees remaining in residential areas of the northern ‘leafy’ suburbs of Sydney allowed the persistence of a range of bat species. The higher bat activity on fertile shale soils indicated that bushland remnants embedded within cities can have high conservation value for bats. Surveys in more urbanized areas of Sydney are needed to test predictions of the models derived in this study.     

The impact of rabbits and cattle on an arid calcareous shrubby grassland in central Australia

Multivariate methods of classification and ordination were used to examine changes in plant composition over a three year period on a calcareous shrubby grassland grazed by rabbits and cattle in central Australia. In a site-time ordination of the data for all years, the season and amount of rainfall was the most important influence, followed by several soil factors and rabbit density. In a site ordination of each year, rabbit density was a minor influence for the pretreatment data but increased in importance over the three years until it was highly correlated with vector one in the final year. This was a result of the exclosure treatments diverging from the controls with extremely high rabbit populations at two of the eighteen plots. When site-time trajectories were plotted through species space, most sites tended to move with season over the three year period towards a common domain. The two heavily grazed sites exhibited a different trajectory; this was due to the behaviour of seven plant species under grazing. In multiple regression analysis, rabbit density, cattle presence and yearly rainfall explained 66% of the variation in total standing biomass. In general, total cover was not affected by grazing treatment, although short term utilisation effects were usually visible in the late dry season. Given its present degraded state, this arid vegetation type is seen as reasonably resilient, requiring extremely heavy rabbit grazing to prevent the plant community responding to the dominating influence of season.Nomenclature follows J. Jessop (ed.), 1981. Flora of Central Australia. The Australian Systematic Botany Society. Reed Press, Sydney.I thank G. Pearce and K. Jones for their diligent data collection, preparation and analysis.     

Understorey gaps influence regeneration dynamics in subtropical coastal dune forest

Dominant understorey species influence forest dynamics by preventing tree regeneration at the seedling stage. We examined factors driving the spatial distribution of the monocarpic species Isoglossa woodii, a dominant understorey herb in coastal dune forests, and the effect that its cover has on forest regeneration. We used line transects to quantify the area of the forest understorey with I. woodii cover and with gaps in the cover. Paired experimental plots were established in semi-permanent understorey gaps with I. woodii naturally absent and in adjacent areas with I. woodii present to compare plant community composition, soil, and light availability between the two habitats. Isoglossa woodii was widespread, covering 65–95% of the understorey, while gaps covered the remaining 5–35% of the area. The spatial distribution of this species was strongly related to tree canopy structure, with I.␣woodii excluded from sites with dense tree cover. Seedling establishment was inhibited by low light availability (<1% of PAR) beneath I.␣woodii. When present, I. woodii reduced the density and species richness of tree seedlings. The tree seedling community beneath I. woodii represented a subset of the seedling community in gaps. Some species that were found in gaps did not occur beneath I. woodii at all. There were no significant differences between the sapling and canopy tree communities in areas with I. woodii gaps and cover. In the coastal dune forest system, seedling survival under I. woodii is dependent on a species’ shade tolerance, its ability to grow quickly during I. woodii dieback, and/or the capacity to regenerate by re-sprouting and multi-stemming. We propose a general conceptual model of forest regeneration dynamics in which the abundant understorey species, I. woodii, limits local tree seedling establishment and survival but gaps in the understorey maintain tree species diversity on a landscape scale.     

Factors influencing the distribution of medium‐sized ground‐dwelling mammals in southeastern mainland Australia

Abstract The forage diggings of medium‐sized ground‐dwelling mammals (bandicoots and potoroos) were recorded over two seasons across 136 forested study sites, representing a stratified sample of the climatic, geological and topographic features of far south‐eastern mainland Australia. Diggings, presumably left by bandicoots, were recorded at a total of 42 sites, and those of potoroos at 27 sites. Statistical models were developed for the occurrence of these diggings, based on environmental attributes measured for each site. At a landscape scale, mean minimum temperature of the coldest month was an important explanatory variable for both groups of animals, with likelihood of their occurrence increasing with increasing temperature during that period. More locally, soil fertility and time since last fire also influenced the occurrence of bandicoot and potoroo diggings, while density of ground cover was additionally important in explaining the occurrence of bandicoot diggings. Bandicoot and potoroo diggings were more likely to occur with decreasing soil fertility and increasing time since fire, while occurrence of bandicoot diggings also increased with increasing density of ground cover. The possible management implications of our findings for conservation of medium‐sized ground‐dwelling mammals in multiple‐use forests are discussed.     

The Influence of Habitat Variables on Bird Communities in Forest Remnants in Costa Rica

This study examined the effects of forest structure (tree species richness, canopy height, percent canopy cover, understory density, tree density and DBH) and avian species traits (nest type and indicator list status) on the diversity, abundance and dissimilarity of bird communities in forest remnants and reforestation areas adjacent to Costa Rican banana plantations. Bird species richness and abundance were significantly related to tree species richness, canopy height and canopy cover in multiple linear regressions, the latter two forest structure variables being the best statistical predictors. Stratification of analyses by bird species indicator categories improved fits of regressions, because correlations with environmental variables differed in sign for different guilds of birds, a result likely to hold for other avifaunas. Analysis of avifauna dissimilarities among sites demonstrated that the species composition of bird communities was highly correlated with forest structure and tree species composition. Logistic regressions indicated that birds making protected (cavity, burrow, pendant, sphere and covered) nests were 2–6 times more likely to be present in the study avifauna than birds making open (cup, saucer, platform and scrape) nests and indicators of disturbed habitats were 11 times more likely to be present than indicators of primary forest. The forest structure data used were simple and inexpensive to collect, and data on avian traits were drawn from the literature. Thus, these methods could easily be replicated at other locations and would be valuable management aids and biodiversity assessment tools for conservation planning.     

The invasive Yellow Crazy Ant and the decline of forest ant diversity in Indonesian cacao agroforests

Throughout the tropics, agroforests are often the only remaining habitat with a considerable tree cover. Agroforestry systems can support high numbers of species and are therefore frequently heralded as the future for tropical biodiversity conservation. However, anthropogenic habitat modification can facilitate species invasions that may suppress native fauna. We compared the ant fauna of lower canopy trees in natural rainforest sites with that of cacao trees in agroforests in Central Sulawesi, Indonesia in order to assess the effects of agroforestry on occurrence of the Yellow Crazy Ant Anoplolepis gracilipes, a common invasive species in the area, and its effects on overall ant richness. The agroforests differed in the type of shade-tree composition, tree density, canopy cover, and distance to the village. On average, 43% of the species in agroforests also occurred in the lower canopy of nearby primary forest and the number of forest ant species that occurred on cacao trees was not related to agroforestry characteristics. However, A. gracilipes was the most common non-forest ant species, and forest ant richness decreased significantly with the presence of this species. Our results indicate that agroforestry may have promoted the occurrence of A. gracilipes, possibly because tree management in agroforests negatively affects ant species that depend on trees for nesting and foraging, whereas A. gracilipes is a generalist when it comes to nesting sites and food preference. Thus, agroforestry management that includes the thinning of tree stands can facilitate ant invasions, thereby threatening the potential of cultivated land for the conservation of tropical ant diversity.     

Targeting hunter distribution based on host resource selection and kill sites to manage disease risk

Endemic and emerging diseases are rarely uniform in their spatial distribution or prevalence among cohorts of wildlife. Spatial models that quantify risk‐driven differences in resource selection and hunter mortality of animals at fine spatial scales can assist disease management by identifying high‐risk areas and individuals. We used resource selection functions (RSFs) and selection ratios (SRs) to quantify sex‐ and age‐specific resource selection patterns of collared (n = 67) and hunter‐killed (n = 796) nonmigratory elk (Cervus canadensis manitobensis) during the hunting season between 2002 and 2012, in southwestern Manitoba, Canada. Distance to protected area was the most important covariate influencing resource selection and hunter‐kill sites of elk (AICw = 1.00). Collared adult males (which are most likely to be infected with bovine tuberculosis (Mycobacterium bovis) and chronic wasting disease) rarely selected for sites outside of parks during the hunting season in contrast to adult females and juvenile males. The RSFs showed selection by adult females and juvenile males to be negatively associated with landscape‐level forest cover, high road density, and water cover, whereas hunter‐kill sites of these cohorts were positively associated with landscape‐level forest cover and increasing distance to streams and negatively associated with high road density. Local‐level forest was positively associated with collared animal locations and hunter‐kill sites; however, selection was stronger for collared juvenile males and hunter‐killed adult females. In instances where disease infects a metapopulation and eradication is infeasible, a principle goal of management is to limit the spread of disease among infected animals. We map high‐risk areas that are regularly used by potentially infectious hosts but currently underrepresented in the distribution of kill sites. We present a novel application of widely available data to target hunter distribution based on host resource selection and kill sites as a promising tool for applying selective hunting to the management of transmissible diseases in a game species.     

The occurrence of herbs and woody juveniles in a hardwood floodplain forest in relation to flooding and light

Abstract. A study of the distribution of herbs, seedlings and vegetative propagules of woody species in a hardwood flood-plain forest along the Upper Rhine in France revealed that the occurrence of most species is significantly correlated to elevation above river level and light transmission in summer. Species confined to higher-lying sites which are only occasionally and briefly flooded in the growing season show most damage upon flooding. Tall herb species occur on sites where more than 5% daylight reaches the herb layer and they only reach a dense cover where flooding is occasional. The occurrence of woody juveniles is negatively correlated with tall herb cover and largely confined to more shaded sites or more frequently flooded sites. The results indicate that both shading and flooding are important for regeneration of woody species and for maintaining species diversity in hardwood flood-plain forests.     

Context dependency in interference competition among birds in an endangered woodland ecosystem

Aim

Much research has quantified species responses to human-modified ecosystems. However, there is limited work on how human-modified ecosystems may reshape competitive interactions between species. Using a 19-year study across 3 million ha, we aimed to answer the question: Are levels of interference competition between bird species context dependent and influenced by habitat structure and productivity? We focussed on the hyper-aggressive behaviour of the Noisy Miner (Manorina melanocephala), which is recognized as a key threatening process for other woodland bird species in Australia. Whether environmental conditions such as amount of forest cover and net primary productivity (NPP) mediate the Noisy Miners' impact remains untested at large spatiotemporal scales.

Location

Temperate woodlands of south-eastern Australia.

Methods

We gathered data on bird site occupancy from repeated surveys of field sites and assembled satellite data on tree cover and NPP. We constructed Bayesian multi-species occupancy/detection models of bird species in woodland patches and tested the fixed and interactive effects of Noisy Miner presence, the amount of tree cover, NPP, and time. We quantified the responses of 31 species, many with known interactions with the Noisy Miner documented previously at fine spatial scales.

Results

We identified negative associations between the Noisy Miner and 18 bird species, including, unexpectedly, both small and large bodied taxa. Site occupancy in some species was influenced by interactions between Noisy Miner presence and increasing amounts of tree cover or productivity. For some species, interference competition by the Noisy Miner is context-dependent and mitigated by increasing tree cover and/or increasing NPP.

Main Conclusions

Our analyses revealed that woodland bird conservation in our study region will be promoted by protecting refugia characterized by areas of high NPP and high tree cover. Preventing vegetation clearing that reduces tree cover could reduce interference competition by the Noisy Miner on parts of the remaining woodland bird community, including species of conservation concern.