OBSERVATIONS OF THE BREEDING BEHAVIOR OF THE YELLOW‐TUFTED WOOD‐ PECKER (MELANERPES CRUENTATUS) IN NAPO PROVINCE, ECUADOR

ABSTRACT ∙ The Yellow‐tufted Woodpecker (Melanerpes cruentatus) is common and conspicuous across most of tropical South America. Nevertheless, there is little information available on its breeding behavior. I describe observations of a breeding pair, made between 15 February and 10 March 2016, near the Biological Reserve Colonso Chalupas in the province of Napo, Ecuador. I observed aggressive interactions between M. cruentatus and Masked Tityras (Tityra semifasciata), likely as a result of competition for nest‐holes. I did not observe cooperative breeding. My observations suggest that breeding in Ecuador may commence as early as February, and that M. cruentatus requires dead, standing tree snags, an element often eliminated from anthropogenic landscapes. The availability of snags should be part of ecosystem management, especially in the buffer zone of a protected area.RESUMEN ∙ Observaciones del comportamiento de anidación del carpintero azulado (Melanerpes cruentatus) en la provincia de Napo, EcuadorEl Carpintero Azulado (Melanerpes cruentatus) es una especie común que se encuentra en gran parte de América del Sur tropical. Sin embargo, hay poca información disponible sobre su comportamiento reproductivo. Detallo observaciones hechas entre el 15 de febrero al 10 de marzo de 2016, sobre una pareja reproductora, cerca de la Reserva Biológica Colonso Chalúpas en la provincia de Napo, Ecuador. Observé interacciones agresivas entre M. cruentatus y Tityra semifasciata, probablemente como resultado de la competencia por huecos aptos para anidar. No observe indicios de reproducción comunal o cooperativa. Mis observaciones sugieren que el periodo reproductivo puede comen‐ zar en febrero en el este de Ecuador y que M. cruentatus requiere árboles muertos en pie para nidificar. Asegurar la disponibilidad de estos árboles debe ser parte del manejo del ecosistema, especialmente en la zona de amortiguamiento de un área protegida

WOODPECKER CAVITY‐TREE SELECTION IN THE ECUADOREAN AMAZON REGION

Abstract ∙ Tree cavities are important as sites for nesting and roosting, but their availability or use has been little studied in the Neotropics. We studied woodpecker (Picidae) cavity‐tree selection in disturbed and undisturbed landscapes in the Amazonian region. We found that woodpeckers excavated predominantly in large dead trees (mean diameter 44 cm). We highlight the importance of dead trees as substrates for cavities in the Ecuadorean Amazon region. We propose that woodpeckers in our study region are potentially important cavity formation agents for other cavity‐nesters, especially in disturbed landscapes.Resumen ∙ Selección de árboles para excavar cavidades por pájaros carpinteros en la región Amazónica Ecuatoriana Las cavidades en árboles son importantes para animales como sitios para anidar y dormir, pero su disponibilidad o uso han sido poco estudiados en el Neotrópico. Estudiamos la selección de árboles como sustratos para cavidades hechos por pájaros carpinteros (Picidae) en paisajes perturbados y no perturbados. Encontramos que los pájaros carpinteros excavaban predominantemente en árboles muertos grandes (diámetro medio de 44 cm). Destacamos la importancia de los árboles muertos como sustratos para las cavidades en la región amazónica ecuatoriana. Proponemos que los pájaros carpinteros son potencialmente importantes para la formación de cavidades para otras aves en la región de estudio

Variation In Habitat Thresholds: An Analysis Of Minimum Habitat Requirements Of North American Breeding Birds

Many species show dramatic changes in population extinction or persistence probability at particular habitat amounts. These `extinction thresholds\u27 could be translated to conservation targets, under the condition that we can derive generalities. I investigated the level of variation in landscape-level habitat thresholds for a suite of North American, forest-associated, breeding birds. Records from Breeding Bird Atlases and the availability of remotely-sensed land cover data allowed me to compare habitat thresholds for 25 species across the states of Massachusetts, Michigan, New York, Ohio, Pennsylvania, and Vermont. I show that variation in thresholds is considerable (Chapter II, III), as thresholds range from 7 to 90% forest cover between species, within regions, and even from 12 and 90% forest cover within species across regions (results for White-throated Sparrow (Zonotrichia albicollis)). I found no universal trend in this variation, although a few species showed a significant increase in threshold amounts with increasing forest cover in the landscape. In Chapter IV, I show that it is possible to assess vertical habitat structure with light detection and ranging (lidar) data. The availability of detailed habitat metrics, such as maximum canopy height and canopy heterogeneity, allowed me to detect detailed extinction thresholds for five species of cavity breeding birds and the Cerulean Warbler (Setophaga cerulea), a species of great conservation concern. Models also showed that some species persist at low forest cover, even though they demonstrate a peak in extinction probability at intermediate levels of forest cover (Chapter V). These peaks in extinction probability correspond with a peak in change in amount of forest cover over time, indicating that change in habitat might be predictive of extinction probability. Estimation of species-specific thresholds, I propose, provides information that can potentially be used to set management targets (Chapter VI). I conclude that we should be wary of extrapolation of thresholds and emphasize that estimation of thresholds should be considered a tool for understanding the process of habitat loss, not a goal in itself

ADDITIONAL RECORDS OF ABERRANT PLUMAGE COLORATION OF THE GROOVE-BILLED ANI (CROTOPHAGA SULCIROSTRIS)

Abstract · Chromatic aberrations have previously been reported for the normally entirely black Groove-billed Ani (Crotophaga sulcirostris). Here, we present three additional observations of the occurrence of chromatic aberrations in this species, in the southwest of Ecuador. In May 2016, we observed two birds with a nearly entirely white coloration, except for a few small black spots, and one pied-colored bird, with a mix of white and black coloration on all main body parts. Most likely, these chromatic aberrations are cases of progressive greying. Future studies should determine whether multiple individuals with chromatic aberration in the same place are a coincidence or due to other reasons.Resumen · Registros adicionales de la coloración aberrante del plumaje en el Garrapatero pico estriado (Crotophaga sulcirostris) Casos de aberraciones cromáticas de plumaje han sido reportados previamente para el Garrapatero Pico Estriado (Crotophaga sulcirostris) una especie cuyo plumaje es normalmente completamente negro. Aquí, presentamos tres observaciones adicionales de ocurrencia de aberraciones cromáticas en esta especie para el sureste de Ecuador. En mayo de 2016 observamos dos individuos con una coloración casi completamente blanca, salvo pequeñas manchas negras, y un individuo que presentaba una mezcla de plumas blancas y negras. Es probable que en este caso se trate de encanecimiento progresivo (“progressive greying”), que puede afectar la mayor parte del plumaje de esta ave. Son necesarios más estudios para determinar si las observaciones de múltiples individuos con aberraciones cromáticas en el mismo lugar, se tratan de una coincidencia o si existen otros factores

Application of habitat thresholds in conservation: Considerations, limitations, and future directions

AbstractHabitat thresholds are often interpreted as the minimum required area of habitat, and subsequently promoted as conservation targets in natural resource policies and planning. Unfortunately, several recent reviews and messages of caution on the application of habitat thresholds in conservation have largely fallen on deaf ears, leading to a dangerous oversimplification and generalization of the concept. We highlight the prevalence of oversimplification/over-generalization of results from habitat threshold studies in policy documentation, the consequences of such over-generalization, and directions for habitat threshold studies that have conservation applications without risking overgeneralization. We argue that in order to steer away from misapplication of habitat thresholds in conservation, we should not focus on generalized nominal habitat values (i.e., amounts or percentages of habitat), but on the use of habitat threshold modeling for comparative exercises of area-sensitivity or the identification of environmental dangers. In addition, we should remain focused on understanding the processes and mechanisms underlying species responses to habitat change. Finally, studies could that focus on deriving nominal value threshold amounts should do so only if the thresholds are detailed, species-specific, and translated to conservation targets particular to the study area only

Clusters of high abundance of plants detected from local indicators of spatial association (LISA) in a semi-deciduous tropical forest.

Plants are rarely randomly distributed across communities, and patchiness is a common spatial pattern in most tropical forests. Clusters of high density of plant individuals are related to internal and external forces, as well as to historical events. The detection of aggregated patterns of plant individuals allows for a better understanding of the internal and external factors that guide the distribution of species. The aim of this research was to detect and characterize clusters of high abundance of plants and species richness in semi-deciduous forests in the Dominican Republic. For this, we collected vegetation data from 575 quadrats in 23 transects (2300 m2 in total) within the Ocoa river basin. Using local Moran's I statistics, we isolated 18 quadrats of high density of individuals. We show that density of individuals can be 2.5 times larger on average than in non-aggregated quadrats, and can reach higher values for shrubs species as well as for palms and vines species. In addition, we found that shrub species are the most abundant group in aggregated quadrats, and density of tree species is significantly smaller than that of shrub species. High density quadrats are predominantly occupied by shrubs, palms and vines, following patterns of species composition and lithology. Detecting clusters of high density of individuals could help in the efficient assessment of richness in semi-deciduous tropical forests, and may support new conservation practices for this valuable but threatened ecosystem

Sequencing Stepping Stones: A Raster-based GIS Model for Routing a Connectivity Corridor through a Fragmented Landscape

Although its effectiveness (or cost-effectiveness) is still debatable, connecting habitat remnants with conservation corridors is an approach to mitigate negative effects of the loss and fragmentation of wildlife habitat on biodiversity. Planning and decision on conservation corridors tend to involve multiple—often subjective and uncertain—factors ranging from environmental and economic to social and political. Thus, actual corridors may not be fully connected but composed of isolated habitat fragments. To offer computational support in planning such ‘stepping stones’ corridors, we design and implement a raster-based GIS model that characterizes and searches for an optimal sequence of isolated patches as stepping stones across a mosaic of land covers. The model is unique in two aspects. First, it simultaneously selects stepping stones to be included and a path through which they are to be traversed, which collectively form a corridor. The latter would be useful information in planning on where to perform certain actions (e.g., planting) to encourage organisms to follow the corridor. Second, unlike existing least-cost path models, it does not require the quantification of land cover types in terms of their suitability (or cost) for being included in the corridor, but only requires the rank-ordering of them. This would not eliminate all the subjectivity or uncertainty involved but reduce it substantially. We apply the model to a conservation project in Rwanda that aims to increase the connectivity of two national parks via the establishment of a hedgerow of native plants for dispersal of bird pollinators. Results suggest that the model allows for a rapid first delineation of candidate routes for stepping stone corridors and facilitates the early exploratory stages of conservation projects.QC 20220818</p

Sequencing Stepping Stones: A Raster-based GIS Model for Routing a Connectivity Corridor through a Fragmented Landscape

Although its effectiveness (or cost-effectiveness) is still debatable, connecting habitat remnants with conservation corridors is an approach to mitigate negative effects of the loss and fragmentation of wildlife habitat on biodiversity. Planning and decision on conservation corridors tend to involve multiple—often subjective and uncertain—factors ranging from environmental and economic to social and political. Thus, actual corridors may not be fully connected but composed of isolated habitat fragments. To offer computational support in planning such ‘stepping stones’ corridors, we design and implement a raster-based GIS model that characterizes and searches for an optimal sequence of isolated patches as stepping stones across a mosaic of land covers. The model is unique in two aspects. First, it simultaneously selects stepping stones to be included and a path through which they are to be traversed, which collectively form a corridor. The latter would be useful information in planning on where to perform certain actions (e.g., planting) to encourage organisms to follow the corridor. Second, unlike existing least-cost path models, it does not require the quantification of land cover types in terms of their suitability (or cost) for being included in the corridor, but only requires the rank-ordering of them. This would not eliminate all the subjectivity or uncertainty involved but reduce it substantially. We apply the model to a conservation project in Rwanda that aims to increase the connectivity of two national parks via the establishment of a hedgerow of native plants for dispersal of bird pollinators. Results suggest that the model allows for a rapid first delineation of candidate routes for stepping stone corridors and facilitates the early exploratory stages of conservation projects.QC 20220818</p

Wildlife roadkill patterns in a fragmented landscape of the Western Amazon

One of the most evident and direct effects of roads on wildlife is the death of animals by vehicle collision. Understanding the spatial patterns behind roadkill helps to plan mitigation measures to reduce the impacts of roads on animal populations. However, although roadkill patterns have been extensively studied in temperate zones, the potential impacts of roads on wildlife in the Neotropics have received less attention and are particularly poorly understood in the Western Amazon. Here, we present the results of a study on roadkill in the Amazon region of Ecuador; a region that is affected by a rapidly increasing development of road infrastructure. Over the course of 50 days, in the wet season between September and November 2017, we searched for road-killed vertebrates on 15.9 km of roads near the city of Tena, Napo province, for a total of 1590 surveyed kilometers. We recorded 593 dead specimens, predominantly reptiles (237 specimens, 40%) and amphibians (190, 32%), with birds (102, 17%) and mammals (64, 11%) being less common. Recorded species were assigned to three functional groups; based on their movement behavior and habitat use (‘slow’, ‘intermediate’ and ‘fast’). Using Ripley’s K statistical analyses and 2D HotSpot Identification Analysis, we found multiple distinct spatial clusters or hotspots, where roadkill was particularly frequent. Factors that potentially determined these clusters, and the prevalence of roadkill along road segments in general, differed between functional groups, but often included land cover variables such as native forest and waterbodies, and road characteristics such as speed limit (i.e. positive effect on roadkill frequency). Our study, which provides a first summary of species that are commonly found as roadkill in this part of the Amazon region, contributes to a better understanding of the negative impacts of roads on wildlife and is an important first step towards conservation efforts to mitigate these impacts