Consequences of a large-scale fragmentation experiment for Neotropical bats : disentangling the relative importance of local and landscape-scale effects

Context Habitat loss, fragmentation and degradation are widespread drivers of biodiversity decline. Understanding how habitat quality interacts with landscape context, and how they jointly affect species in human-modified landscapes, is of great importance for informing conservation and management. Objectives We used a whole-ecosystem manipulation experiment in the Brazilian Amazon to investigate the relative roles of local and landscape attributes in affecting bat assemblages at an interior-edge-matrix disturbance gradient. Methods We surveyed bats in 39 sites, comprising continuous forest (CF), fragments, forest edges and intervening secondary regrowth. For each site, we assessed vegetation structure (local-scale variable) and, for five focal scales, quantified habitat amount and four landscape configuration metrics. Results Smaller fragments, edges and regrowth sites had fewer species and higher levels of dominance than CF. Regardless of the landscape scale analysed, species richness and evenness were mostly related to the amount of forest cover. Vegetation structure and configurational metrics were important predictors of abundance, whereby the magnitude and direction of response to configurational metrics were scale-dependent. Responses were ensemble-specific with local-scale vegetation structure being more important for frugivorous than for gleaning animalivorous bats. Conclusions Our study indicates that scale-sensitive measures of landscape structure are needed for a more comprehensive understanding of the effects of fragmentation on tropical biota. Although forest fragments and regrowth habitats can be of conservation significance for tropical bats our results further emphasize that primary forest is of irreplaceable value, underlining that their conservation can only be achieved by the preservation of large expanses of pristine habitat

Field boundary features can stabilise bee populations and the pollination of mass-fowering crops in rotational systems

1. Pollinators experience large spatio-temporal fluctuations in resource availability when mass-flowering crops are rotated with resource-poor cereal crops. Yet, few studies have considered the effect this has on pollinator population stability, nor how this might be mitigated to maintain consistent crop pollination services. 2. We assess the potential of boundary features (standard narrow 1m grassy margins, hedgerows and wide 4m agri-environment margins) to support and stabilise pollinator populations and pollination service in agricultural landscapes under crop rotation. Assuming a six-year rotation, we use a process-based pollinator model to predict yearly pollinator population size and in-crop visitation rates to oilseed rape and field bean across 117 study landscapes in England with varying amounts of boundary features. We model both ground-nesting bumblebees and solitary bees and compare the predictions including and excluding boundary features from the landscapes. 3. Ground-nesting bumblebee populations, whose longer-lifetime colonies bene�t from continuity of resources, were larger and more stable (relative to the no-features scenario) in landscapes with more boundary features. Ground-nesting solitary bee populations were also larger but not significantly more stable, except with the introduction of wide permanent agri-environment margins, due to their shorter lifetimes and shorter foraging/dispersal ranges. 4. Crop visitation by ground-nesting bumblebees was greater and more stable in landscapes with more boundary features, partly due to increased colony growth prior to crop flowering. Time averaged crop visitation by ground-nesting solitary bees was slightly lower, due to females dividing their foraging time between boundary features and the crop, but the more stable delivery compensated for this by nonetheless increasing the minimum pollination service delivered in any given year. 5. Synthesis and applications. Boundary features have an important role in stabilising pollinator populations and pollination service in rotational systems, although maintenance of larger semi-natural habitat patches may be more effective for stabilising less mobile solitary bee populations. We recommend using combinations of boundary features, accounting for pollinator range when spacing features/rotating crops, and synchronising boundary feature management with crop rotation to maximise their stabilising benefits

Local and Landscape Factors Determining Occurrence of Phyllostomid Bats in Tropical Secondary Forests

Neotropical forests are being increasingly replaced by a mosaic of patches of different successional stages, agricultural fields and pasture lands. Consequently, the identification of factors shaping the performance of taxa in anthropogenic landscapes is gaining importance, especially for taxa playing critical roles in ecosystem functioning. As phyllostomid bats provide important ecological services through seed dispersal, pollination and control of animal populations, in this study we assessed the relationships between phyllostomid occurrence and the variation in local and landscape level habitat attributes caused by disturbance. We mist-netted phyllostomids in 12 sites representing 4 successional stages of a tropical dry forest (initial, early, intermediate and late). We also quantitatively characterized the habitat attributes at the local (vegetation structure complexity) and the landscape level (forest cover, area and diversity of patches). Two focal scales were considered for landscape characterization: 500 and 1000 m. During 142 sampling nights, we captured 606 individuals representing 15 species and 4 broad guilds. Variation in phyllostomid assemblages, ensembles and populations was associated with variation in local and landscape habitat attributes, and this association was scale-dependent. Specifically, we found a marked guild-specific response, where the abundance of nectarivores tended to be negatively associated with the mean area of dry forest patches, while the abundance of frugivores was positively associated with the percentage of riparian forest. These results are explained by the prevalence of chiropterophilic species in the dry forest and of chiropterochorous species in the riparian forest. Our results indicate that different vegetation classes, as well as a multi-spatial scale approach must be considered for evaluating bat response to variation in landscape attributes. Moreover, for the long-term conservation of phyllostomids in anthropogenic landscapes, we must realize that the management of the habitat at the landscape level is as important as the conservation of particular forest fragments

Analysis of Genomic Sequence Data Reveals the Origin and Evolutionary Separation of Hawaiian Hoary Bat Populations

We examine the genetic history and population status of Hawaiian hoary bats (Lasiurus semotus), the most isolated bats on Earth, and their relationship to northern hoary bats (Lasiurus cinereus), through whole-genome analysis of single-nucleotide polymorphisms mapped to a de novo-assembled reference genome. Profiles of genomic diversity and divergence indicate that Hawaiian hoary bats are distinct from northern hoary bats, and form a monophyletic group, indicating a single ancestral colonization event 1.34 Ma, followed by substantial divergence between islands beginning 0.51 Ma. Phylogenetic analysis indicates Maui is central to the radiation across the archipelago, with the southward expansion to Hawai‘i and westward to O‘ahu and Kaua‘i. Because this endangered species is of conservation concern, a clearer understanding of the population genetic structure of this bat in the Hawaiian Islands is of timely importance

Forest bird inventory of the Kahuku unit of Hawai`i Volcanoes National Park

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.The Kahuku Unit of the Hawai`i Volcanoes National Park (HAVO) was surveyed for native and non-native birds from January to September of 2005. Bird habitat comprised of forest, woodland, and grassland was divided into five separate regions, and these were surveyed with variable circular plot count methodology to generate estimates of abundance and occurrence. Sampling coverage was more intensive (i.e. several times more count transects and stations) than in past surveys, for more accurate estimates of range and population size. In addition to point counts, we recorded incidental observations to supplement the survey. Ten native and 14 non-native bird species were detected within the region. The most abundant and widespread native forest birds observed were the `Ōma`o (Myadestes obscurus), Hawai`i `Amakihi (Hemignathus virens virens), `I`iwi (Vestiaria coccinea), and `Apapane (Himatione sanguinea sanguinea). The second largest populations of three endangered forest bird species in Hawai`i—`Akiapōlā`au (Hemignathus munroi), Hawai`i `Ākepa (Loxops coccineus), and Hawai`i Creeper (Oreomystis mana)—were centered in the Ka`ū Forest Reserve and extended into the Kahuku Unit. The detections within the boundaries of the unit now add these endangered species to HAVO. The Hawai`i `Elepaio (Chasiempis sandwichensis) shows evidence of a regional population decline. The two native species that use habitat other than forest—Hawaiian Hawk (Buteo solitarius) and Pacific Golden-Plover (Pluvialis fulva)—were rarely detected in the study areas. The Japanese White-eye (Zosterops japonicus) and Northern Cardinal (Cardinalis cardinalis) were the mostabundant non-native species. The remaining non-native species were uncommon to rare and were restricted to either the dry leeward or wetter windward sides of the Kahuku Unit.This project was carried out under a cooperative agreement between the National Park Service, Pacific Island Network and the Pacific Cooperative Studies Unit, University of Hawaii at Manoa (No. H8080040012, task agreement No. J8080040035)

Hawaiian Forest Birds: The Past, Present And Future Status Of An Endangered Avifauna

The Hawaiian forest birds are among the most endangered avifauna of the world. Entire bird groups have disappeared from the Hawaiian Islands, and of the more than fifty, historically-known species of Hawaiian honeycreeper, only 17 remain. Due to the extreme geographical isolation, few birds colonized the Hawaiian Islands but, released from direct competition, predation, and disease, these founders flourished and evolved amid the heterogeneous geography of the archipelago. This process of colonization and speciation is best characterized by the honeycreepers; the largest radiation of endemic forest birds in the Hawaiian Islands, or for that matter, birds on any oceanic archipelago. But this remarkable avifauna has suffered great loses since the arrival of humankind. Extinctions and population declines began with the inadvertent introduction of predatory rats, overharvesting of flightless species and destruction of lowland forest by Polynesians. Habitat destruction and degradation and predation accelerated with the arrival of Westerners and their domestic animals and pests, leading to more extinction and increasing rates of population decline. The introduction of mosquito vectors, avian disease pathogens, and vertebrate and invertebrate competitors led to the displacement of many native bird species from lowland forests. Today, on protected lands, there are apparently stable populations of only a handful of the remaining species. However, habitat degradation, predation, disease and food web disruption by invasive hymenoptera continue to impact critical populations. Additionally, climate change will likely increase habitat degradation, disease, and food web disruption further restricting remaining populations to smaller and more dispersed refuges. Although the fate of Hawaiian forest birds appears bleak, there are reasons for hope. Some populations of Hawaii amakihi have evolved tolerance to avian malaria and are burgeoning in the once quieted lowland forests. Captive breeding and release programs have prevented the extinction of at least two species and consortiums of managed conservation lands increase the extent and suitability of remaining forest bird habitat

Influencing Activity of Bats by Dimly Lighting Wind Turbine Surfaces with Ultraviolet Light

Wind energy producers need deployable devices for wind turbines that prevent bat fatalities. Based on the speculation that bats approach turbines after visually mistaking them for trees, we tested a potential light-based deterrence method. It is likely that the affected bats see ultraviolet (UV) light at low intensities. Here, we present the results of a multi-month experiment to cast dim, flickering UV light across wind turbine surfaces at night. Our objectives were to refine and test a practical system for dimly UV-illuminating turbines while testing whether the experimental UV treatment influenced the activity of bats, birds, and insects. We mounted upward-facing UV light arrays on turbines and used thermal-imaging cameras to quantify the presence and activity of night-flying animals. The results demonstrated that the turbines can be lit to the highest reaches of the blades with “invisible” UV light, and the animal responses to such experimental treatment can be concurrently monitored. The UV treatment did not significantly change nighttime bat, insect, or bird activity at the wind turbine. Our findings show how observing flying animals with thermal cameras at night can help test emerging technologies intended to variably affect their behaviors around wind turbines

Supplement 1. MATLAB source code for the generation of a null model via matrix permutation methods and the test of the difference between pairs of correlation matrices.

<h2>File List</h2><blockquote> <p>Downloadable MATLAB files<br> <a href="permcorr.m">permcorr.m</a><br> <a href="PERMCORR.txt">permcorr.txt</a><br> <a href="permdiff.m">permdiff.m</a><br> <a href="PERMDIFF.txt">permdiff.txt</a></p> <p> </p></blockquote><h2>Description</h2><blockquote> <p>This supplement contains the MATLAB code files for testing the difference between pairs of correlation matrices via the generation of a null model with matrix permutation methods. <br> The MATLAB function permdiff.m calculates a sum of squared differences between elements of two input matrices and the probability that this difference is significantly different than zero. It invokes the function permcorr.m to randomly permute the input matrices and generate a null model. The files are provided in both a compiled MATLAB code format (i.e., *.m) and a text format.</p> </blockquote