Predicting which species will occur together in the future, and where, remains one of the greatest challenges in ecology, and requires a sound understanding of how the abiotic and biotic environments interact with dispersal processes and history across scales. Biotic interactions and their dynamics influence species' relationships to climate, and this also has important implications for predicting future distributions of species. It is already well accepted that biotic interactions shape species' spatial distributions at local spatial extents, but the role of these interactions beyond local extents (e.g. 10 km2 to global extents) are usually dismissed as unimportant. In this review we consolidate evidence for how biotic interactions shape species distributions beyond local extents and review methods for integrating biotic interactions into species distribution modelling tools. Drawing upon evidence from contemporary and palaeoecological studies of individual species ranges, functional groups, and species richness patterns, we show that biotic interactions have clearly left their mark on species distributions and realised assemblages of species across all spatial extents. We demonstrate this with examples from within and across trophic groups. A range of species distribution modelling tools is available to quantify species environmental relationships and predict species occurrence, such as: (i) integrating pairwise dependencies, (ii) using integrative predictors, and (iii) hybridising species distribution models (SDMs) with dynamic models. These methods have typically only been applied to interacting pairs of species at a single time, require a priori ecological knowledge about which species interact, and due to data paucity must assume that biotic interactions are constant in space and time. To better inform the future development of these models across spatial scales, we call for accelerated collection of spatially and temporally explicit species data. Ideally, these data should be sampled to reflect variation in the underlying environment across large spatial extents, and at fine spatial resolution. Simplified ecosystems where there are relatively few interacting species and sometimes a wealth of existing ecosystem monitoring data (e.g. arctic, alpine or island habitats) offer settings where the development of modelling tools that account for biotic interactions may be less difficult than elsewhere.

/pdf/the-role-of-biotic-interactions-in-shaping-distributions-and-e49xst0zpo.pdf

The role of biotic interactions in shaping distributions and realised assemblages of species: implications for species distribution modelling

The global emergence and spread of the pathogenic, virulent, and highly transmissible fungus Batrachochytrium dendrobatidis, resulting in the disease chytridiomycosis, has caused the decline or extinction of up to about 200 species of frogs. Key postulates for this theory have been completely or partially fulfilled. In the absence of supportive evidence for alternative theories despite decades of research, it is important for the scientific community and conservation agencies to recognize and manage the threat of chytridiomycosis to remaining species of frogs, especially those that are naive to the pathogen. The impact of chytridiomycosis on frogs is the most spectacular loss of vertebrate biodiversity due to disease in recorded history.

/pdf/spread-of-chytridiomycosis-has-caused-the-rapid-global-3258w0sbzd.pdf

Spread of Chytridiomycosis Has Caused the Rapid Global Decline and Extinction of Frogs

White-nose syndrome (WNS) is a condition associated with an unprecedented bat mortality event in the northeastern United States. Since the winter of 2006*2007, bat declines exceeding 75% have been observed at surveyed hibernacula. Affected bats often present with visually striking white fungal growth on their muzzles, ears, and/or wing membranes. Direct microscopy and culture analyses demonstrated that the skin of WNS-affected bats is colonized by a psychro-philic fungus that is phylogenetically related to Geomyces spp. but with a conidial morphology distinct from characterized members of this genus. This report characterizes the cutaneous fungal infection associated with WNS.

/pdf/bat-white-nose-syndrome-an-emerging-fungal-pathogen-qqlp0xmu2c.pdf

Bat White-Nose Syndrome: An Emerging Fungal Pathogen?

Summary
1. Biological invasions are numerous in fresh waters around the world. At least hundreds of freshwater species have been moved outside of their native ranges by vectors such as ballast water, canals, deliberate introductions, and releases from aquaria, gardens, and bait buckets. As a result, many bodies of fresh water now contain dozens of alien species.

2. Invasions are highly nonrandom with respect to the taxonomic identity and biological traits of the invaders, the ecological characteristics of the ecosystems that are invaded, and the geographical location of the ecosystems that supply and receive the invaders.

3. Some invaders have had deep and pervasive effects on the ecosystems that they invade. Classes of ecologically important invaders in fresh waters include molluscs that are primary consumers and disrupt the food web from its base, fishes that disrupt the food web from its apex or centre, decapods that act as powerful omnivores, aquatic plants that have strong engineering effects and affect the quality and quantity of primary production, and diseases, which probably have been underestimated as an ecological force.

4. The number of alien species in freshwater ecosystems will increase in the future as new aliens are moved outside of their native ranges by humans, and as established aliens fill their potential ranges. Alien species create “no-analogue” ecosystems that will be difficult to manage in the future. We may be able to reduce future impacts of invaders by making more serious efforts to prevent new invasions and manage existing invaders.

5. Thematic implications: interactions between alien species and other contemporary stressors of freshwater ecosystems are strong and varied. Because disturbance is generally thought to favour invasions, stressed ecosystems may be especially susceptible to invasions, as are highly artificial ecosystems. In turn, alien species can strongly alter the hydrology, biogeochemical cycling, and biotic composition of invaded ecosystems, and thus modulate the effects of other stressors. In general, interactions between alien species and other stressors are poorly studied.

/pdf/alien-species-in-fresh-waters-ecological-effects-5fvv6usa04.pdf

Alien species in fresh waters: ecological effects, interactions with other stressors, and prospects for the future

Anthropogenic trade and development have broken down dispersal barriers, facilitating the spread of diseases that threaten Earth's biodiversity. We present a global, quantitative assessment of the amphibian chytridiomycosis panzootic, one of the most impactful examples of disease spread, and demonstrate its role in the decline of at least 501 amphibian species over the past half-century, including 90 presumed extinctions. The effects of chytridiomycosis have been greatest in large-bodied, range-restricted anurans in wet climates in the Americas and Australia. Declines peaked in the 1980s, and only 12% of declined species show signs of recovery, whereas 39% are experiencing ongoing decline. There is risk of further chytridiomycosis outbreaks in new areas. The chytridiomycosis panzootic represents the greatest recorded loss of biodiversity attributable to a disease.

/pdf/amphibian-fungal-panzootic-causes-catastrophic-and-ongoing-3nhy6yqj5n.pdf

Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity

Marking anurans by invasive methods has been strongly debated on the grounds of ethics, public opinion, the
potential for infection, and potential impacts on behavior and survival of marked animals. One possible alternative is the use of photographs to enable identification of individuals by their patterns. This requires that individuals have distinguishable markings that remain constant through time. We compared the accuracy of the photographic identification method (PIM) to marked frogs in the field to evaluate whether PIM can be used to identify adult Greeneyed Tree Frogs, Litoria genimaculata. We captured 59 animals on second and subsequent nights of trips. Thirteen were correctly identified as recaptures; 61.5% of them by using the PIM. This was a substantial (39.5%) improvement over chance (expected rate if frogs assigned as recaptures at random was 22%), but was less accurate than the toe-tipping method, with which only one recapture was misidentified (92.3% correct). The majority of frogs, including all of the individuals that were not correctly identified, lacked a distinct dorsal "hourglass" pattern. This may have contributed to the relatively high error rate. We found that the PIM was slower than toe-tipping animals in both time taken for application and identifying individuals. We conclude that the PIM needs to be carefully validated before it is applied to a new species. For L. genimaculata it may be of use in short-term studies when the goal is to reduce the chance of doublesampling individuals. Even then, it will probably only be worth using when a relatively high proportion of the population is being sampled on each occasion, so that a 60 to 70% reduction in double-sampling rates over random is worth achieving.

Evaluation of the photographic identification method (PIM) as a tool to identify adult Litoria Genimaculata (anura: hylidae)

Hygiene protocol for handling amphibians in field studies

Aim
Rapidly evolving pathogens may exert diversifying selection on genes involved in host immune defence including those encoding antimicrobial peptides (AMPs). Amphibian skin peptides are one important defence against chytridiomycosis, an emerging infectious disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). We examined the population-level variation in this innate immune defence to understand its relationship with disease dynamics.

Location
Queensland, Australia.

Methods
We examined skin peptide defences in five geographically distinct populations of Australian green-eyed treefrogs, Litoria genimaculata. Skin peptide samples were collected from 52 frogs from three upland populations that previously declined as chytridiomycosis emerged, but subsequently recovered, and from 34 frogs in two lowland populations that did not decline. Historical samples of skin peptides preceding Bd emergence were not available from any population.

Results
In general, lowland populations had more effective peptide defences than upland populations. Peptide profiles were similar among populations, although relative amounts of peptides expressed differed significantly among populations and were more variable in the uplands. Infected frogs in upland populations carried a significantly higher infection burden compared to lowland populations. The presence of effective AMPs in the skin of L. genimaculata does not eliminate infection; however, more effective peptide defences may limit infection intensity and the progression of disease.

Main conclusions
The population bottleneck in upland populations caused by chytridiomycosis emergence did not appear to produce responses to selection for more effective peptide defences against chytridiomycosis compared to lowland populations of L. genimaculata. This does not exclude the possibility that current peptide defences have adapted in response to disease emergence. A suggestive (P < 0.10) interaction between infection status and population indicates that in lowland populations, infected individuals tend to be those with lower relative intensities of AMPs, whereas in the upland populations, infected and uninfected individuals are similar. Thus, both the AMPs and the environment may act to mediate resistance to Bd infection.

Adaptations of skin peptide defences and possible response to the amphibian chytrid fungus in populations of Australian green‐eyed treefrogs, Litoria genimaculata

Nicole Kenyon

Papers

Spread of Chytridiomycosis Has Caused the Rapid Global Decline and Extinction of Frogs

Evaluation of the photographic identification method (PIM) as a tool to identify adult Litoria Genimaculata (anura: hylidae)

Hygiene protocol for handling amphibians in field studies

Adaptations of skin peptide defences and possible response to the amphibian chytrid fungus in populations of Australian green‐eyed treefrogs, Litoria genimaculata

Immune evasion or avoidance: Fungal skin infection linked to reduced defence peptides in Australian green-eyed treefrogs, Litoria serrata