Effects of forest fragmentation on the vertical stratification of neotropical bats

Vertical stratification is a key component of the biological complexity of rainforests. Understanding community- and species-level responses to disturbance across forest strata is paramount for evidence-based conservation and management. However, even for bats, known to extensively explore multiple layers of the complex three-dimensional forest space, studies are biased towards understory-based surveys and only few assessments of vertical stratification were done in fragmented landscapes. Using both ground and canopy mist-nets, we investigated how the vertical structure of bat assemblages is influenced by forest fragmentation in the experimentally fragmented landscape of the Biological Dynamics of Forest Fragments Project, Central Amazon, Brazil. Over a three year-period, we captured 3077 individuals of 46 species in continuous forest (CF) and in 1, 10 and 100 ha forest fragments. In both CF and forest fragments, the upper forest strata sustained more diverse bat assemblages than the equivalent understory layer, and the midstory layers had significantly higher bat abundance in fragments than in CF. Artibeus lituratus and Rhinophylla pumilio exhibited significant shifts in their vertical stratification patterns between CF and fragments (e.g. R. pumilio was more associated with the upper strata in fragments than in CF). Altogether, our study suggests that fragmentation modulates the vertical stratification of bat assemblages

Secondary forest buffers the effects of fragmentation on aerial insectivorous bat species following 30 years of passive forest restoration

Passive forest restoration can buffer the effects of habitat loss on biodiversity. We acoustically surveyed aerial insectivorous bats in a whole-ecosystem fragmentation experiment in the Brazilian Amazon over a 2-year period, across 33 sites, comprising continuous old-growth forest, remnant fragments, and regenerating secondary forest matrix. We analyzed the activity of 10 species/sonotypes to investigate occupancy across habitat types and responses to fragment size and interior-edge-matrix (IEM) disturbance gradients. Employing a multiscale approach, we investigated guild (edge foragers, forest specialists, flexible forest foragers, and open space specialists) and species-level responses to vegetation structure and forest cover, edge, and patch density across six spatial scales (0.5–3 km). We found species-specific habitat occupancy patterns and nuanced responses to fragment size and the IEM disturbance gradient. For example, Furipterus horrens had lower activity in secondary forest sites and the interior and edge of the smallest fragments (1 and 10 ha) compared to continuous forest, and only two species (Pteronotus spp.) showed no habitat preference and no significant responses across the IEM and fragment size gradients. Only the Molossus sonotype responded negatively to vegetation structure. We uncovered no negative influence of forest cover or edge density at guild or species-level. Our results indicate that reforestation can buffer the negative effects of fragmentation and although these effects can still be detected in some species, generally aerial insectivorous bats appear to be in recovery after 30 years of passive forest restoration. Our findings reinforce the need to protect regenerating forests while conserving vast expanses of old-growth forest

Influence of vegetable oil sources on quality parameters of broiler meat

The use of different vegetable oils in animal nutrition has allowed the producer to obtain highly energetic diets at very low costs, while offering an optimum and well-appreciated product to the consumer. Nowadays, numerous efforts are taken to enrich poultry meat with polyunsaturated fatty acids (PUFA) and, especially, with omega-3 fatty acids, because of the proven benefits on human health (Kinsella et al., 1990; Knapp, 1991). But, up to now there have not been done complementary studies dealing with the influence of such nutritive improvements on the different technological characteristics of poultry meat. Besides this, there also exist few experiments dealing with the influence of the enrichment with PUFA on the subjective parameters of organoleptic quality. Those experiments are usually more related to the use of fish ingredients in animal diets. The aim of the present experiment was to study the effects of different vegetable oils (rapeseed, soybean, sunflower and linseed) on the technical, nutritive and organoleptic quality of chicken meat, and on the profiles of essential fatty acids (EFA) in the cloacal fat and in the tissues

Dioxinas y PCBS en la alimentación de pollos de carne : efecto sobre parámetros productivos y utilización de nutrientes

Este experimento tiene por objetivo evaluar la repercusión de la adición de grasas que presentan dioxinas (D) y bifenilos policlorados (PCBs) en la alimentación de pollos broiler. Se estudió su efecto sobre el rendimiento productivo, coeficiente de digestibilidad y el depósito de grasa de los animales. 64 pollos broiler hembra línea genética Ross 308 fueron alimentados hasta los 47 días de edad con dos piensos experimentales con un nivel de inclusión del 6% de aceite de pescado. Las dos materias grasas utilizadas diferían en el nivel de contaminación: nivel alto HD 9,78 pg TEQD pg/g y 19,02 pg TEQPCBs/g y nivel bajo LD l,95pg TEQD y 7,69 pg TEQPCBs/g. No se observaron diferencias estadísticamente significativas en el consumo medio diario (CMD), ganancia media diaria (GMD) ni en el índice de transformación (IT) entre los tratamientos experimentales. Se realizaron dos balances de digestibilidad desde el día 14 al 16 y del 37 al 39. No se observaron diferencias estadísticamente significativas en la digestibilidad de la materia seca (DMS), y digestibilidad de la materia orgánica (DMO) si bien la digestibilidad del extracto etéreo (DEE) en primeras edades fue superior para los animales del tratamiento HD (LD 80.57% vs. HD 86.39%; P<0.01). Por otro lado, el rendimiento de la canal fue superior para los animales del tratamiento HD (LD 80.51% vs. HD 81.72%; P< 0.01) sin observarse diferencias estadísticamente significativas en el resto de parámetros estudiados (peso vivo PV, peso canal PC, y grasa abdominal GA). En conclusión, los aceites comerciales de pescado con concentraciones de contaminantes de hasta 9,78 pg TEQD/g y19,02 pg TEQPCB/g, no alteran los parámetros productivos ni el rendimiento en los pollos de carne.An experiment was designed to study the effect of the addition of dioxin and polychlorinated biphenyls PCBs contaminated fats in broiler chickens diets, on the productive yield parameters, the fat digestibility and deposit. Sixty four female broilers (genetic line Ross) were lodged in 16 cages distributed in to two treatments consisting of two experimental diets with 6% of fish oil with 9.78 pg TEQD and 19.02 pg TEQPCB/g ofoil for the high level (HD) and 1.95 pg TEQD and 7.69 pg TEQPCB/g of oil for the low level (LD). The experiment lasted until day 47 oflife ofanimals and productive controls were made at days 22 and 47. Studied parameters included, daily mean intake (CMD), daily mean gain (GMD) and the conversion index (IT). No statistical differences were found in this parameters. From day 14 to 16 and from 37 to 39 two digestibility trials were performed. There was no significant statistical difference in dry matter digestibility (DMS), organic matter digestibility (DMO), but ether extract digestibility (EED) was higher during first trial for HD treatment (LD 80,57% vs. HD 86,39%; P < 0.01). Regarding live weight (W), carcase weight (CW), carcase yield (RC) and abdominal fat (AF), only RC showed statistical differences with highervalues for HD treatment (LD 80,51% vs. HD 81,72%; P<0.01)

Edge effects and vertical stratification of aerial insectivorous bats across the interface of primary-secondary Amazonian rainforest

Research ArticleEdge effects, abiotic and biotic changes associated with habitat boundaries, are key drivers of community change in fragmented landscapes. Their influence is heavily modulated by matrix composition. With over half of the world’s tropical forests predicted to become forest edge by the end of the century, it is paramount that conservationists gain a better understanding of how tropical biota is impacted by edge gradients. Bats comprise a large fraction of tropical mammalian fauna and are demonstrably sensitive to habitat modification. Yet, knowledge about how bat assemblages are affected by edge effects remains scarce. Capitalizing on a whole-ecosystem manipulation in the Central Amazon, the aims of this study were to i) assess the consequences of edge effects for twelve aerial insectivorous bat species across the interface of primary and secondary forest, and ii) investigate if the activity levels of these species differed between the understory and canopy and if they were modulated by distance from the edge. Acoustic surveys were conducted along four 2-km transects, each traversing equal parts of primary and ca. 30-year-old secondary forest. Five models were used to assess the changes in the relative activity of forest specialists (three species), flexible forest foragers (three species), and edge foragers (six species). Modelling results revealed limited evidence of edge effects, except for forest specialists in the understory. No significant differences in activity were found between the secondary or primary forest but almost all species exhibited pronounced vertical stratification. Previously defined bat guilds appear to hold here as our study highlights that forest bats are more edge-sensitive than edge foraging bats. The absence of pronounced edge effects and the comparable activity levels between primary and old secondary forests indicates that old secondary forest can help ameliorate the consequences of fragmentation on tropical aerial insectivorous batsinfo:eu-repo/semantics/publishedVersio

Geographical variation in the high-duty cycle echolocation of the cryptic common mustached bat Pteronotus cf. rubiginosus (Mormoopidae)

The use of bioacoustics as a tool for bat research is rapidly increasing worldwide. There is substantial evidence that environmental factors such as weather conditions or habitat structure can affect echolocation call structure in bats and thus compromise proper species identification. However, intraspecific differences in echolocation due to geographical variation are poorly understood, which poses a number of issues in terms of method standardization. We examined acoustic data for Pteronotus cf. rubiginosus from the Central Amazon and the Guiana Shield. We provide the first evidence of intraspecific geographic variation in bat echolocation in the Neotropics, with calls significantly differing in almost all standard acoustic parameters for the two lineages of this clade. We complement our bioacoustic data with molecular and morphological data for both species. Considerable overlap in trait values prevents reliable discrimination between the two sympatric Pteronotus based on morphological characters. On the other hand, significant divergence in the frequency of maximum energy suggests that bioacoustics can be used to readily separate both taxa despite extensive intraspecific variability in their echolocation across the Amazon. Given the relative lack of barriers preventing contact between bat populations from the Central Amazon and French Guiana, the documented acoustic variation needs to be further studied in geographically intermediate locations to understand the potential isolation processes that could be causing the described divergence in echolocation and to determine whether this variation is either discrete or continuous

Terminal restriction fragment length polimorphism (T-RFLP) : una herramienta útil para valorar la dinámica y la diversidad de la población microbiana en aves y cerdos

El ecosistema intestinal es un medio complejo y dinámico que puede verse afectado puntualmente por numerosos factores propios del individuo pero también por numerosos factores ambientales o externos (como puede ser la dieta). La necesidad de conocer de una forma rápida y reproducible cómo es la dinámica de la población bacteriana, así como su estructura está siendo posible gracias al desarrollo de técnicas moleculares aplicadas como DGGE (Denaturing Gradient Gel Electrophoresis)1, TGGE (Temperatura Gradient Gel Electrophoresis)2, SSCP (Single Strand Conformation Polimorphism)3 y T-RFLP (Terminal Restriction Fragment Length Polimorphism)4. Estas técnicas moleculares aprovechan la característica de universalidad del gen que codifica para el 16S ARNr, presente en prácticamente la totalidad de las especies bacterianas. La presencia de secuencias altamente conservadas hace posible el diseño de primers o cebadores que permitan la amplificación mediante PCR del total de la población bacteriana de la muestra. Son las regiones variables (polimórficas) del gen que codifica el 16S ARNr las que se aprovechan para la diferenciación. En el T-RFLP, estas diferencias entre especies o géneros bacterianos se ponen de manifiesto tras la digestión con endonucleasas de restricción del producto de PCR marcado. Únicamente el fragmento del extremo terminal será visible por electroforesis capilar gracias al mareaje fluorescente de uno de los cebadores. El perfil que se genera (electroferograma) nos permite obtener información del número de fragmentos (riqueza), de su tamaño en pares de bases (bp) (para una posible inferencia de la especie bacteriana presente) y de su altura (lo que puede orientar sobre la importancia de un determinado grupo bacteriano dentro de una muestra), siempre sin olvidar las desviaciones inherentes propias de la PCR. Es posible también calcular la frecuencia de detección de un determinado pico (especie) respecto al total de muestras así como construir con ayuda de programas informáticos matrices de similitud o dendogramas. Empleando herramientas disponibles en la red como: TAP-tRFLP del software Ribosomal Database Project II o ISPaR del software MiCA (Microbial Community Analysis) es posible hacer una asignación teórica de la especie o género bacteriano a cada uno de los picos en base a las secuencias depositadas por otros autores. Sin embargo un mismo pico puede tener su origen en distintas especies. Disponer alternativamente de secuencias propias obtenidas tras la clonación del 16S ARN de muestras de nuestros animales nos permite hacer una asignación teórica más firme, considerando únicamente aquellas especies mayoritarias encontradas

First record of Micronycteris sanborni (Chiroptera: Phyllostomidae) from Central Amazonia, Brazil: range expansion and description of its echolocation

This note reports the first record of Micronycteris sanborni in Amazonas State, Brazil. It extends the species ’ known range > 2000 km northwestward and represents the first record of M. sanborni in a humid tropical ecosystem, suggesting that the species might not be exclusive to dry areas, as previously thought. The individual was captured in Vismia -dominated secondary forest within the fragmented landscape of the Biological Dynamics of Forest Fragments Project. We present morphometric data and provide the first description of the echolocation calls of this poorly known species

How a haemosporidian parasite of bats gets around: the genetic structure of a parasite, vector and host compared.

Parasite population structure is often thought to be largely shaped by that of its host. In the case of a parasite with a complex life cycle, two host species, each with their own patterns of demography and migration, spread the parasite. However, the population structure of the parasite is predicted to resemble only that of the most vagile host species. In this study, we tested this prediction in the context of a vector-transmitted parasite. We sampled the haemosporidian parasite Polychromophilus melanipherus across its European range, together with its bat fly vector Nycteribia schmidlii and its host, the bent-winged bat Miniopterus schreibersii. Based on microsatellite analyses, the wingless vector, and not the bat host, was identified as the least structured population and should therefore be considered the most vagile host. Genetic distance matrices were compared for all three species based on a mitochondrial DNA fragment. Both host and vector populations followed an isolation-by-distance pattern across the Mediterranean, but not the parasite. Mantel tests found no correlation between the parasite and either the host or vector populations. We therefore found no support for our hypothesis; the parasite population structure matched neither vector nor host. Instead, we propose a model where the parasite's gene flow is represented by the added effects of host and vector dispersal patterns

Interplay between local and landscape-scale effects on the taxonomic, functional and phylogenetic diversity of aerial insectivorous Neotropical bats

Context Human-modified landscapes are globally ubiquitous. It is critical to understand how habitat loss and fragmentation impact biodiversity from both a local habitat context and landscape-scale perspective to inform land management and conservation strategies. Objectives We used an experimentally fragmented landscape in the Brazilian Amazon to investigate variation in aerial insectivorous bat diversity in response to local habitat and wider landscape characteristics, applying a multiscale approach. Methods We conducted bat acoustic surveys at 33 sites, comprising old secondary forests and fragments of primary forest. Taxonomic, functional and phylogenetic diversity facets were calculated within a Hill numbers framework. We analysed responses to fragment size, interior-edge-matrix gradients, as well as local vegetation structure, continuous forest cover, edge density and patch density across five spatial scales (0.5 km - 3 km) surrounding detector locations. Results Compared with continuous forest, secondary forest matrix around the smallest fragments harboured lower diversity. The overall negative effect of the matrix became less pronounced with increasing fragment size. In contrast, forest edges generally contained higher taxonomic, functional and phylogenetic diversity. We found subtle scale-sensitive associations for FD, responding positively to forest cover (at the 1 km scale) and negatively to edge (1 km scale) and patch density (2.5 km scale). Conclusions Despite a low-contrast matrix of tall secondary forest surrounding fragments after ~30 years of forest recovery, aerial insectivorous bat diversity is not comparable to continuous primary forest. Assemblage functional diversity responds to compositional and configurational landscape characteristics at scales deserving further evaluation at guild and species level