Spatial scale changes the drivers of beta-diversity along land-use, environmental and geographic gradients

Understanding the patterns of spatial change in community composition (betadiversity), and the processes that structure biological communities are central themes in ecology. While the impacts of habitat change on beta-diversity are well-studied, most studies have been restricted to a single spatial scale. As a result, the effects of changing spatial scale on beta-diversity patterns across both natural and human-modified habitats are little known. My thesis targets the effect of spatial scale on tree and bird beta-diversity in the Asia-Pacific region across gradients of latitude, elevation and land-use change. The First Chapter uses tree data (> one billion stems and > 2500 species) from 15 long-term ForestGEO plots across the Asia-Pacific region to show how spatial scale changes the relationship between beta-diversity and latitude. At small spatial scales, beta-diversity decreased with increasing latitude; but at large spatial scales, beta-diversity did not change with increasing latitude. Different relationships across spatial scales were caused by differences in species richness, which influenced β-diversity values at small spatial scales, but not at large spatial scales. The Second Chapter uses bird data from Sri Lanka to show how horizontal (geographic) and vertical (elevation) distances can influence bird beta-diversity within three different land-use types (protected rainforests, reserve buffers and intensive agriculture). I show that bird beta-diversity within all land-use types were similar across horizontal distances. However, bird betadiversity within land-use types were not similar across vertical distances; protected rainforests had higher beta-diversity than the other two habitats. The Third Chapter uses bird data from the Western Ghats – Sri Lanka biodiversity hotspot to determine the drivers of bird community assembly at three different spatial scales. The geographic barrier (the Palk Strait) is the most important driver of bird beta-diversity at large spatial scale. Land-use and environment were equally important at intermediate scales and land-use was the most important driver at small scales. In conclusion, this thesis demonstrates the importance of sampling at multiple spatial scales to better understand natural and human-influenced betadiversity. In the First Chapter I showed that spatial scale changes the relationship between beta-diversity and latitude; and improving sampling representativeness avoids the species richness dependence of beta-diversity. In the Second Chapter I demonstrated the crucial importance of conserving rainforests across the full elevation range available. In the Third Chapter I showed that considering community assembly processes at multiple spatial scales while selecting sites for biological conservation holds great promise for preventing further species loss.Thesis (Ph.D.) -- University of Adelaide, School of Biological Sciences, 201

Morphology, ecology, and behaviour of Hylarana intermedia, a Western Ghats frog

Despite being common in the Western Ghats-Sri Lanka biodiversity hotspot, Golden-backed frogs (Hylarana, Ranidae) remain poorly studied. In this paper, we present some preliminary data on the morphology, behaviour, and habitat use of Hylarana intermedia, a member of the Hylarana aurantiaca species group. We find evidence for female biased size dimorphism, as well as potential shape differences between the sexes in this species. Additionally, we investigate the relationships between traits that may contribute to male conspicuousness (call rates, dorsal coloration, and body size) in two breeding habitats, a paddy field and a trench. Our results suggest both size-dependent and environment-dependent variation in call rate and colour in this species. Specifically, we find evidence against the adoption of sneaker mating strategies by small males in H. intermedia, and instead find variation both within and between populations in traits contributing to male conspicuousness. We conclude by proposing future directions for research on this common frog species

Natural Windbreaks Sustain Bird Diversity in a Tea- Dominated Landscape

Windbreaks often form networks of forest habitats that improve connectivity and thus conserve biodiversity, but little is known of such effects in the tropics. We determined bird species richness and community composition in windbreaks composed of remnant native vegetation amongst tea plantations (natural windbreaks), and compared it with the surrounding primary forests. Fifty-one, ten-minute point counts were conducted in each habitat type over three days. Despite the limited sampling period, our bird inventories in both natural windbreaks and primary forests were nearly complete, as indicated by bootstrap true richness estimator. Bird species richness and abundance between primary forests and windbreaks were similar, however a difference in bird community composition was observed. Abundances of important functional groups such as frugivores and insectivores did not vary between habitat types but nectarivores were more abundant in windbreaks, potentially as a result of the use of windbreaks as traveling routes, foraging and nesting sites. This preliminary study suggests that natural windbreaks may be important habitats for the persistence of bird species in a production landscape. However, a better understanding of the required physical and compositional characteristics for windbreaks to sustain bird communities is needed for effective conservation management

Squamata, Scincidae, Eutropis trivittata (Hardwicke and Gray, 1827): distribution extension

We report the first record of the three-banded skink Eutropis trivittata (Hardwicke and Gray, 1827) (Reptilia: Scincidae) for Andhra Pradesh, India, based on a specimen from Araku, Vishakapatnam district. This report also helps in understanding the distribution of this species in South East India.

Non-pollinator fig wasp impact on the reproductive success of an invasive fig tree: why so little?

Classical biological control agents fail to achieve an impact on their hosts for a variety of reasons and an understanding of why they fail can help shape decisions on subsequent releases. Ornamental Ficus microcarpa is a widely planted avenue fig tree that is invasive in countries where its pollinator (Eupristina verticillata) is also introduced. This tree also supports more than 20 species of non-pollinating fig wasps (NPFW) that feed in the figs and have the potential to reduce the plant’s reproduction. Odontofroggatia galili, one of the most widely introduced NPFW, has larvae that develop in galled ovules that might otherwise develop into seeds or support pollinator larvae. We examined the distribution and relative abundance of the pollinator and O. galili on F. microcarpa in China, towards the northern limit of the tree’s natural range, and in Italy where the two species have been introduced. Where they co-existed, we also recorded the impact of varying densities of O. galili on F. microcarpa seed and pollinator production. O. galili and E. verticillata displayed contrasting habitat preferences in China, with O. galili almost absent from warmer sites. O. galili abundance and sex ratios varied between the natural and introduced ranges. Figs with more O. galili contained fewer seeds and pollinator offspring, but reproduction was rarely inhibited totally. Additional species with a greater impact in the figs they occupy are needed if biocontrol of F. microcarpa is to be effective

Ecological filtering shapes the impacts of agricultural deforestation on biodiversity

Funding: This project was funded by the National Natural Science Foundation of China (Grants 32122057 and 3198810 to FH) and the Ministry of Science and Technology of China (Grant 2022YFF0802300 to FH), and received further support from Tsinghua University Initiative Scientific Research Program (Grant 20223080017 to LY).The biodiversity impacts of agricultural deforestation vary widely across regions. Previous efforts to explain this variation have focused exclusively on the landscape features and management regimes of agricultural systems, neglecting the potentially critical role of ecological filtering in shaping deforestation tolerance of extant species assemblages at large geographical scales via selection for functional traits. Here we provide a large-scale test of this role using a global database of species abundance ratios between matched agricultural and native forest sites that comprises 71 avian assemblages reported in 44 primary studies, and a companion database of 10 functional traits for all 2,647 species involved. Using meta-analytic, phylogenetic and multivariate methods, we show that beyond agricultural features, filtering by the extent of natural environmental variability and the severity of historical anthropogenic deforestation shapes the varying deforestation impacts across species assemblages. For assemblages under greater environmental variability—proxied by drier and more seasonal climates under a greater disturbance regime—and longer deforestation histories, filtering has attenuated the negative impacts of current deforestation by selecting for functional traits linked to stronger deforestation tolerance. Our study provides a previously largely missing piece of knowledge in understanding and managing the biodiversity consequences of deforestation by agricultural deforestation.Peer reviewe

Replication Data for The use of species–area relationships to partition the effects of hunting and deforestation on bird extirpations in a fragmented landscape

Forest fragmentation is often accompanied by an increase in hunting intensity. Both factors are known drivers of species extirpations, but understanding of their independent effects is poor. Our goal was to partition the effects of hunting and fragmentation on bird species extirpations and to identify bird traits that make species more vulnerable to these two stressors

Data from: Influence of gaze and directness of approach on the escape responses of the Indian rock lizard, Psammophilus dorsalis (Gray, 1831)

Animals often evaluate the degree of risk posed by a predator and respond accordingly. Since many predators orient their eyes towards prey while attacking, predator gaze and directness of approach could serve as conspicuous indicators of risk to prey. The ability to perceive these cues and discriminate between high and low predation risk should benefit prey species through both higher survival and decreased energy expenditure. We experimentally examined whether Indian rock lizards (Psammophilus dorsalis) can perceive these two indicators of predation risk by measuring the variation in their fleeing behaviour in response to type of gaze and approach by a human predator. Overall, we found that the gaze and approach of the predator influenced flight initiation distance, which also varied with attributes of the prey (i.e. size/sex and tail-raise behaviour). Flight initiation distance (FID) was 43% longer during direct approaches with direct gaze compared with tangential approaches with averted gaze. In further, exploratory, analyses, we found that FID was 23% shorter for adult male lizards than for female or young male (FYM) lizards. In addition, FYM lizards that showed a tail-raise display during approach had a 71% longer FID than those that did not. Our results suggest that multiple factors influence the decision to flee in animals. Further studies are needed to test the generality of these factors and to investigate the proximate mechanisms underlying flight decisions

Flight Initiation Distance data

Data on flight initiation distance were collected in the field according to an experimental protocol described in the associated paper. Each column of this csv file is described in more detail in the accompanying ReadMe file