Parallel evolution in an island archipelago revealed by genomic sequencing of Hipposideros leaf-nosed bats.

Body size is a key morphological attribute, often used to delimit species boundaries among closely related taxa. But body size can evolve in parallel, reaching similar final states despite independent evolutionary and geographic origins, leading to faulty assumptions of evolutionary history. Here, we document parallel evolution in body size in the widely distributed leaf-nosed bat genus Hipposideros, which has misled both taxonomic and evolutionary inference. We sequenced reduced representation genomic loci and measured external morphological characters from three closely related species from the Solomon Islands archipelago, delimited by body size. Species tree reconstruction confirms the paraphyly of two morphologically designated species. The nonsister relationship between large-bodied H. dinops lineages found on different islands indicates that large-bodied ecomorphs have evolved independently at least twice in the history of this radiation. A lack of evidence for gene flow between sympatric, closely related taxa suggests the rapid evolution of strong reproductive isolating barriers between morphologically distinct populations. Our results position Solomon Islands Hipposideros as a novel vertebrate system for studying the repeatability of parallel evolution under natural conditions. We conclude by offering testable hypotheses for how geography and ecology could be mediating the repeated evolution of large-bodied Hipposideros lineages in the Solomon Islands.

Environmental variables influence patterns of mammal co-occurrence following introduced predator control.

Co-occurring species often overlap in their use of resources and can interact in complex ways. However, shifts in environmental conditions or resource availability can lead to changes in patterns of species co-occurrence, which may be exacerbated by global escalation of human disturbances to ecosystems, including conservation-directed interventions. We investigated the relative abundance and co-occurrence of two naturally sympatric mammal species following two forms of environmental disturbance: wildfire and introduced predator control. Using 14 years of abundance data from repeat surveys at long-term monitoring sites in south-eastern Australia, we examined the association between a marsupial, the common brushtail possum Trichosurus vulpecula, and a co-occurring native rodent, the bush rat Rattus fuscipes. We asked: In a fox-controlled environment, are the abundances of common brushtail possums and bush rats affected by environmental disturbance and each other's presence? Using Bayesian regression models, we tested hypotheses that the abundance of each species would vary with changes in environmental and disturbance variables, and that the negative association between bush rats and common brushtail possums was stronger than the association between bush rats and disturbance. Our analyses revealed that bush rat abundance varied greatly in relation to environmental and disturbance variables, whereas common brushtail possums showed relatively limited variation in response to the same variables. There was a negative association between common brushtail possums and bush rats, but this association was weaker than the initial decline and subsequent recovery of bush rats in response to wildfires. Using co-occurrence analysis, we can infer negative relationships in abundance between co-occurring species, but to understand the impacts of such associations, and plan appropriate conservation measures, we require more information on interactions between the species and environmental variables. Co-occurrence can be a powerful and novel method to diagnose threats to communities and understand changes in ecosystem dynamics.

Vangunu giant rat (Uromys vika) survives in the Zaira Community Resource Management Area, Solomon Islands.

Described in 2017 and known only from the holotype, Uromys vika is surely among the world's least studied rodents. This critically endangered species is facing a rapidly increasing scale for threat from logging of its primary lowland forest habitat, on the only island on which it occurs-Vangunu, Solomon Islands. However, a deep traditional ecological knowledge of U. vika is held by Vangunu's people. Using camera traps and guided by this knowledge, we aimed to make additional records of U. vika in the last major block of Vangunu's primary forest. We successfully captured 95 images of what we postulate is four different individuals. The forests at Zaira represent the last suitable habitat remaining for this species, and recent development consent for logging at Zaira will lead to its extinction if permitted to proceed.

Evolutionary relationships and population genetics of the Afrotropical leaf-nosed bats (Chiroptera, Hipposideridae).

The Old World leaf-nosed bats (Hipposideridae) are aerial and gleaning insectivores that occur throughout the Paleotropics. Both their taxonomic and phylogenetic histories are confused. Until recently, the family included genera now allocated to the Rhinonycteridae and was recognized as a subfamily of Rhinolophidae. Evidence that Hipposideridae diverged from both Rhinolophidae and Rhinonycteridae in the Eocene confirmed their family rank, but their intrafamilial relationships remain poorly resolved. We examined genetic variation in the Afrotropical hipposiderids Doryrhina, Hipposideros, and Macronycteris using relatively dense taxon-sampling throughout East Africa and neighboring regions. Variation in both mitochondrial (cyt-b) and four nuclear intron sequences (ACOX2, COPS, ROGDI, STAT5) were analyzed using both maximum likelihood and Bayesian inference methods. We used intron sequences and the lineage delimitation method BPP-a multilocus, multi-species coalescent approach-on supported mitochondrial clades to identify those acting as independent evolutionary lineages. The program StarBEAST was used on the intron sequences to produce a species tree of the sampled Afrotropical hipposiderids. All genetic analyses strongly support generic monophyly, with Doryrhina and Macronycteris as Afrotropical sister genera distinct from a Paleotropical Hipposideros; mitochondrial analyses interpose the genera Aselliscus, Coelops, and Asellia between these clades. Mitochondrial analyses also suggest at least two separate colonizations of Africa by Asian groups of Hipposideros, but the actual number and direction of faunal interchanges will hinge on placement of the unsampled African-Arabian species H. megalotis. Mitochondrial sequences further identify a large number of geographically structured clades within species of all three genera. However, in sharp contrast to this pattern, the four nuclear introns fail to distinguish many of these groups and their geographic structuring disappears. Various distinctive mitochondrial clades are consolidated in the intron-based gene trees and delimitation analyses, calling into question their evolutionary independence or else indicating their very recent divergence. At the same time, there is now compelling genetic evidence in both mitochondrial and nuclear sequences for several additional unnamed species among the Afrotropical Hipposideros. Conflicting appraisals of differentiation among the Afrotropical hipposiderids based on mitochondrial and nuclear loci must be adjudicated by large-scale integrative analyses of echolocation calls, quantitative morphology, and geometric morphometrics. Integrative analyses will also help to resolve the challenging taxonomic issues posed by the diversification of the many lineages associated with H. caffer and H. ruber.

Ecological generalism and resilience of tropical island mammals to logging: A 23 year test.

Tropical forest disturbance is a key driver of global biodiversity decline. On continents, the effects of logging are greatest on endemic species, presumably because disturbance is more likely to cover narrower distributions (the "cookie cutter" model). Islands hold disproportionate biodiversity, and are subject to accelerating biotic homogenization, where specialist endemics are lost while generalists persist. We tested responses of tropical island mammals to logging at multiple spatial scales, using a long-term experimental test in a Pacific archipelago. The most widely distributed ecological generalists did not decline after logging, and we detected no overall changes in relative abundance or species diversity. However, endemics with small ranges did decline in response to logging. The least mobile and most range-restricted species declined even at the smallest spatial scale, supporting the cookie cutter model for sedentary species, and suggesting that habitat change due to selective logging is contributing to biotic homogenization on islands.

A decision tree for assessing the risks and benefits of publishing biodiversity data.

Inadequate information on the geographical distribution of biodiversity hampers decision-making for conservation. Major efforts are underway to fill knowledge gaps, but there are increasing concerns that publishing the locations of species is dangerous, particularly for species at risk of exploitation. While we recognize that well-informed control of location data for highly sensitive taxa is necessary to avoid risks, such as poaching or habitat disturbance by recreational visitors, we argue that ignoring the benefits of sharing biodiversity data could unnecessarily obstruct conservation efforts for species and locations with low risks of exploitation. We provide a decision tree protocol for scientists that systematically considers both the risks of exploitation and potential benefits of increased conservation activities. Our protocol helps scientists assess the impacts of publishing biodiversity data and aims to enhance conservation opportunities, promote community engagement and reduce duplication of survey efforts.

Tailoring release protocols to individual species and sites: one size does not fit all.

Reintroduction programs for threatened species often include elaborate release strategies designed to improve success, but their advantages are rarely tested scientifically. We used a set of four experiments to demonstrate that the influence of release strategies on short-term reintroduction outcomes is related to both intrinsic and extrinsic factors. We compared different reintroduction strategies for three mammal species in an arid environment where exotic mammalian predators were removed. Wild greater stick-nest rats selected vegetation shelter sites with greater structural density than captive-bred rats, travelled further from the release site and experienced lower rates of mortality. In comparison, there was no difference in mortality or movement between wild and captive-bred greater bilbies. Burrowing bettongs and greater bilbies were also subjected to immediate and delayed release strategies and whilst no difference was detected in bilbies, bettongs that were subjected to delayed releases lost less weight and took less time to establish burrows than those that were immediately released. Interspecific differences in treatment response were attributed to predation risk, the nature of the release site, and behavioural traits such as shelter investment and sociality. Our varied results highlight the inadequacies of review articles focusing on optimum release protocols due to their attempt to generalise across species and release sites. We provide an example of a predictive model to guide future release strategy experimentation that recognises the range of intrinsic and extrinsic factors influencing reintroduction outcomes. We encourage researchers to treat programs experimentally, identify individual site and species characters that may influence release strategies and record data on movements, mortality, weight dynamics, and settling times and distances. The inherent issues of small sample size and low statistical power that plague most reintroduction experiments suggests there is also a need for increased standardisation and publication of data sets to enable appropriate meta-analyses to occur.