Soil δ13C and δ15N baselines clarify biogeographic heterogeneity in isotopic discrimination of European badgers (Meles meles)

Isotopic techniques have been used to study phenomena in the geological, environmental, and ecological sciences. For example, isotopic values of multiple elements elucidate the pathways energy and nutrients take in the environment. Isoscapes interpolate isotopic values across a geographical surface and are used to study environmental processes in space and time. Thus, isoscapes can reveal ecological shifts at local scales, and show distribution thresholds in the wider environment at the macro-scale. This study demonstrates a further application of isoscapes, using soil isoscapes of 13C/12C and 15N/14N as an environmental baseline, to understand variation in trophic ecology across a population of Eurasian badgers (Meles meles) at a regional scale. The use of soil isoscapes reduced error, and elevated the statistical signal, where aggregated badger hairs were used, and where individuals were identified using genetic microarray analysis. Stable isotope values were affected by land-use type, elevation, and meteorology. Badgers in lowland habitats had diets richer in protein and were adversely affected by poor weather conditions in all land classes. It is concluded that soil isoscapes are an effective way of reducing confounding biases in macroscale, isotopic studies. The method elucidated variation in the trophic and spatial ecology of economically important taxa at a landscape level. These results have implications for the management of badgers and other carnivores with omnivorous tendencies in heterogeneous landscapes.

Niche Partitioning of 5 Sympatric Bornean Ungulates in Response to Spatiotemporal Variation in Fruit Availability and Resulting Implications for Predator-Prey Interactions

<p>Borneo’s rainforests are experiencing some of the fastest deforestation rates worldwide and are home to increasingly vulnerable species, most of which remain poorly understood. Bornean rainforests exhibit dramatic fluctuations in fruit and seed availability during mast-fruiting events which can exert considerable influence on frugivore ecology. Comprehensive spatiotemporal assessments of habitat use, resource partitioning, and responses to fruit availability in mast-fruiting rainforests are lacking for most species, including ungulates. The distribution and habitat use of an apex predator, the Sunda clouded leopard (Neofelis diardi), may be largely shaped by the availability of these ungulates. Yet, factors driving the spatial ecology of this elusive felid remain uncertain. I aimed to quantify spatiotemporal habitat use dynamics of these species and consequently inform effective conservation planning. Specifically, I quantified the effects of human activity, forest type, elevation, and mast-induced fluctuations in resources on the habitat use of lesser mousedeer (Tragulus kanchil), greater mousedeer (T. napu), Bornean yellow muntjacs (Muntiacus atherodes), red muntjacs (M. muntjak), and bearded pigs (Sus barbatus) in Gunung Palung National Park, West Kalimantan, Indonesian Borneo. I applied data from an extensive camera trapping study (n = 42,610 trap nights) to a modified single-season occupancy model to evaluate habitat use over space and time. I then applied estimates of occurrence (Ψ) of the five ungulate species to quantify if habitat use of the Sunda clouded leopard was influenced by prey occurrence and thus if this apex predator responded to bottom-up effects of resource variability. The results from the ungulate modelling revealed that forest type was an important predictor of habitat use of all ungulate species, each preferring different forest habitats. Habitat use estimates were highest in peat swamp forests for lesser mousedeer (Ψ = 0.92 ± 0.05), alluvial bench forests for greater mousedeer (Ψ = 0.52 ± 0.08), lowland granite forests for yellow (Ψ = 0.95 ± 0.07) and red muntjacs (Ψ = 0.98 ± 0.09), and freshwater swamp forests for bearded pigs (Ψ = 0.84 ± 0.07). Bearded pigs exhibited a link between variation in fruit availability and habitat use, indicating an ability to respond to resource variability. Occupancy modelling for Sunda clouded leopards revealed forest type, fruit availability, and bearded pig occurrence as the best predictors of habitat use. The highest estimates were associated with lowland granite forests (Ψ = 0.87 ± 0.09). My results reveal a novel pattern of niche partitioning through both food and habitat resources among five sympatric ungulate species and demonstrate that Sunda clouded leopards may use fruiting events as a cue for abundant prey. My research sheds light on important factors influencing habitat use of understudied ungulates and an apex predator and can be used to refine estimates of habitat suitability across a greater landscape to inform conservation practice amidst continually shrinking remnant forests in Indonesian Borneo.</p>

Niche Partitioning of 5 Sympatric Bornean Ungulates in Response to Spatiotemporal Variation in Fruit Availability and Resulting Implications for Predator-Prey Interactions

<p>Borneo’s rainforests are experiencing some of the fastest deforestation rates worldwide and are home to increasingly vulnerable species, most of which remain poorly understood. Bornean rainforests exhibit dramatic fluctuations in fruit and seed availability during mast-fruiting events which can exert considerable influence on frugivore ecology. Comprehensive spatiotemporal assessments of habitat use, resource partitioning, and responses to fruit availability in mast-fruiting rainforests are lacking for most species, including ungulates. The distribution and habitat use of an apex predator, the Sunda clouded leopard (Neofelis diardi), may be largely shaped by the availability of these ungulates. Yet, factors driving the spatial ecology of this elusive felid remain uncertain. I aimed to quantify spatiotemporal habitat use dynamics of these species and consequently inform effective conservation planning. Specifically, I quantified the effects of human activity, forest type, elevation, and mast-induced fluctuations in resources on the habitat use of lesser mousedeer (Tragulus kanchil), greater mousedeer (T. napu), Bornean yellow muntjacs (Muntiacus atherodes), red muntjacs (M. muntjak), and bearded pigs (Sus barbatus) in Gunung Palung National Park, West Kalimantan, Indonesian Borneo. I applied data from an extensive camera trapping study (n = 42,610 trap nights) to a modified single-season occupancy model to evaluate habitat use over space and time. I then applied estimates of occurrence (Ψ) of the five ungulate species to quantify if habitat use of the Sunda clouded leopard was influenced by prey occurrence and thus if this apex predator responded to bottom-up effects of resource variability. The results from the ungulate modelling revealed that forest type was an important predictor of habitat use of all ungulate species, each preferring different forest habitats. Habitat use estimates were highest in peat swamp forests for lesser mousedeer (Ψ = 0.92 ± 0.05), alluvial bench forests for greater mousedeer (Ψ = 0.52 ± 0.08), lowland granite forests for yellow (Ψ = 0.95 ± 0.07) and red muntjacs (Ψ = 0.98 ± 0.09), and freshwater swamp forests for bearded pigs (Ψ = 0.84 ± 0.07). Bearded pigs exhibited a link between variation in fruit availability and habitat use, indicating an ability to respond to resource variability. Occupancy modelling for Sunda clouded leopards revealed forest type, fruit availability, and bearded pig occurrence as the best predictors of habitat use. The highest estimates were associated with lowland granite forests (Ψ = 0.87 ± 0.09). My results reveal a novel pattern of niche partitioning through both food and habitat resources among five sympatric ungulate species and demonstrate that Sunda clouded leopards may use fruiting events as a cue for abundant prey. My research sheds light on important factors influencing habitat use of understudied ungulates and an apex predator and can be used to refine estimates of habitat suitability across a greater landscape to inform conservation practice amidst continually shrinking remnant forests in Indonesian Borneo.</p>

The Spatial Ecology of the Timber Rattlesnake (Crotalus horridus) in southeastern Louisiana

The Timber Rattlesnake (Crotalus horridus) has a large distribution spanning much of the eastern United States. Because temperature, habitat type, prey composition and abundance, and a variety of other factors may dictate reptile behavior, populations of conspecific species may exhibit behavioral differences across latitudinal and elevational gradients. Using radio telemetry, we tracked 10 adult Timber Rattlesnakes (7 males, 3 females) from May 2016 to June 2017 in southeastern Louisiana to examine the spatial ecology of male and non-gravid female snakes. Mean annual and seasonal home ranges of non-gravid female Timber Rattlesnakes were not statistically different from that of males. Mean seasonal home range sizes and average distances travelled of both sexes was smallest in winter, and had a general increasing trend beginning in spring with a peak in fall. These increases seemed to coincide with the breeding season, taking place from early July until the end of November. Comparison of this study with other studies throughout its distribution could have implications towards future management of conservation for other southern populations of Timber Rattlesnakes.

Community Ecology of Epiphytes and other Arboreal Plants in the New Zealand Eco-region

<p><b>Epiphytes and other structurally-dependent plants have a spatial ecology and community structure intrinsically linked to that of the host trees in the forest, unlike fully terrestrial plants. Understanding of the ecological implications of this from a theoretical perspective is in its infancy. New Zealand’s south temperate rainforest, whilst not as species rich as tropical forests, hosts one of the richest temperate epiphyte floras. Our understanding of the ecological processes structuring the epiphyte communities of New Zealand forests is however lacking. Here, I present four key studies seeking to add to our knowledge of epiphyte community structure, host specificity and spatial ecology in the New Zealand eco-region.</b></p> <p>First, I tested if seed size determined the likelihood of woody plant species occurring epiphytically on tree ferns (their arboreality) – Chapter 2. Arboreality was negatively related to seed size, with only smaller-seeded species commonly occurring on tree ferns. However, the effect of seed size reduced in later life history stages, as expected. These small-seeded species, most notably Weinmannia racemosa, appear to be utilising an alternative recruitment strategy by establishing epiphytically on the tree fern trunks.</p> <p>Second, on Cyathea dealbata host tree ferns, I tested patterns of species accumulation, metacommunity network structure, and differences in vertical stratification (Chapter 3). Epiphytes and climbers followed a species accumulation model of succession between tree ferns of different sizes and between older and younger portions of the tree fern. The metacommunity network showed patterns of species co-occurrence and nestedness consistent with null expectations. Epiphytes of different habits and different dispersal syndromes show different vertical profiles of occurrence, with bird-dispersed species occurring more often near the top of the tree fern than other taxa.</p> <p>To understand an unusual pattern in epiphyte between-host structuring, I quantified the relationship between epiphytic plant and sooty mould assemblages in New Zealand montane beech forest (Chapter 4). Due to the presence of host specific scale insects, the sooty mould was limited to two of three co-dominant canopy tree species. On these two host species, epiphyte richness was significantly reduced. The host size-richness relationship in these two species was also removed, with species composition significantly altered compared to the mould free host species. My results are consistent with the sooty mould amensally excluding the epiphytes and it can be considered as a part of a keystone species complex (with the host beeches and scale insects). This produces a strong pattern of parallel host specificity otherwise not seen in epiphyte assemblages.</p> <p>Lastly, I compared the differences in spatial niche and host species diversity between three arboreal plants, with divergent ecophysiology, on Lord Howe Island (Chapter 5). These focal species were a dwarf mistletoe, an epiphytic orchid and an epiphytic fern. The mistletoe was restricted to thinner branches, and had a significantly different niche to both epiphyte taxa. The host diversity of the mistletoe and orchid both differed significantly from null model expectations. However, the epiphytic fern (Platycerium bifurcatum) had a host diversity consistent with null expectations.</p> <p>Taken together, these studies increase our understanding of epiphyte community assembly in New Zealand and provide a platform to encourage further work in this field. They also provide results that expand understanding of spatial patterns between host and up vertical clines.</p>

Community Ecology of Epiphytes and other Arboreal Plants in the New Zealand Eco-region

<p><b>Epiphytes and other structurally-dependent plants have a spatial ecology and community structure intrinsically linked to that of the host trees in the forest, unlike fully terrestrial plants. Understanding of the ecological implications of this from a theoretical perspective is in its infancy. New Zealand’s south temperate rainforest, whilst not as species rich as tropical forests, hosts one of the richest temperate epiphyte floras. Our understanding of the ecological processes structuring the epiphyte communities of New Zealand forests is however lacking. Here, I present four key studies seeking to add to our knowledge of epiphyte community structure, host specificity and spatial ecology in the New Zealand eco-region.</b></p> <p>First, I tested if seed size determined the likelihood of woody plant species occurring epiphytically on tree ferns (their arboreality) – Chapter 2. Arboreality was negatively related to seed size, with only smaller-seeded species commonly occurring on tree ferns. However, the effect of seed size reduced in later life history stages, as expected. These small-seeded species, most notably Weinmannia racemosa, appear to be utilising an alternative recruitment strategy by establishing epiphytically on the tree fern trunks.</p> <p>Second, on Cyathea dealbata host tree ferns, I tested patterns of species accumulation, metacommunity network structure, and differences in vertical stratification (Chapter 3). Epiphytes and climbers followed a species accumulation model of succession between tree ferns of different sizes and between older and younger portions of the tree fern. The metacommunity network showed patterns of species co-occurrence and nestedness consistent with null expectations. Epiphytes of different habits and different dispersal syndromes show different vertical profiles of occurrence, with bird-dispersed species occurring more often near the top of the tree fern than other taxa.</p> <p>To understand an unusual pattern in epiphyte between-host structuring, I quantified the relationship between epiphytic plant and sooty mould assemblages in New Zealand montane beech forest (Chapter 4). Due to the presence of host specific scale insects, the sooty mould was limited to two of three co-dominant canopy tree species. On these two host species, epiphyte richness was significantly reduced. The host size-richness relationship in these two species was also removed, with species composition significantly altered compared to the mould free host species. My results are consistent with the sooty mould amensally excluding the epiphytes and it can be considered as a part of a keystone species complex (with the host beeches and scale insects). This produces a strong pattern of parallel host specificity otherwise not seen in epiphyte assemblages.</p> <p>Lastly, I compared the differences in spatial niche and host species diversity between three arboreal plants, with divergent ecophysiology, on Lord Howe Island (Chapter 5). These focal species were a dwarf mistletoe, an epiphytic orchid and an epiphytic fern. The mistletoe was restricted to thinner branches, and had a significantly different niche to both epiphyte taxa. The host diversity of the mistletoe and orchid both differed significantly from null model expectations. However, the epiphytic fern (Platycerium bifurcatum) had a host diversity consistent with null expectations.</p> <p>Taken together, these studies increase our understanding of epiphyte community assembly in New Zealand and provide a platform to encourage further work in this field. They also provide results that expand understanding of spatial patterns between host and up vertical clines.</p>

Seasonal and age-specific dynamics of the Griffon Vulture’s home range and movements in the Eastern Rhodopes

The spatial ecology of the Eurasian Griffon Vulture (Gyps fulvus) has been a subject of scientific interest for long due to its conservation status, critical ecosystem role, gregarious lifestyle and complex foraging behavior. The trans-border Eastern Rhodope Mountain in Bulgaria and Greece holds an increasing population of the species and one of the largest on the Balkan Peninsula. We used high-frequency GPS data from 13 Griffon Vultures from this population to study their movements, home range size and its seasonal or age specific dynamics. The overall foraging home range (95% kernel) was 3,204 km2 and the core area of activity (50% kernel) was 256.5 km2. We found high seasonal variation of the home range size. Vultures were foraging over larger areas in the summer and spring but their activity was limited to four times smaller areas in winter. We found no age specific variation in the home range sizes but the non-adult vultures showed tendency to conduct exploratory movements far from the breeding colony. Our results can be used for planning conservation efforts in the areas of high importance for the species.