How rare species conservation management can be strengthened with the use of ecological niche modelling: The case for endangered endemic Gundlach’s Hawk and Cuban Black-Hawk

AbstractForty-six percent of tropical raptors are threatened by habitat loss and fragmentation. Tropical raptors are generally rare species. The scarce information on distribution patterns of rare species makes it difficult to establish reliable conservation plans. We used ecological niche modelling to obtain good predictions of occurrence of two case species, the rare and endemic Gundlach’s and Cuban Black-hawks in Cuba, based on presence-only data. We used records from an intensive survey undertaken in natural and modified environments. Data were integrated with environmental variables using Maxent to predict species distributions. Subsequently, we overlaid the resulting predicted distributions, the land use map and the protected areas layers to establish potential suitable habitat for these endemics and to determine if a better design of protected areas than the existing one can be proposed using both hawks’ distribution in the design. Gundlach’s Hawk distribution was fragmented, depending on forest distribution. Cuban Black-Hawk distribution was narrow, near the coastline. Forests and mangrove represent 57% and 45% of Gundlach’s Hawk and Cuban Black-Hawk model predictions, respectively. 71% of the total forest area was represented in the distribution of Gundlach’s Hawk. Mangrove area overlaps 45% of the Cuban Black-Hawk distribution. Six protected areas preserved 50% and 92% of their distributions, respectively. With few presence-only data of rare species, Maxent models were statistically and ecologically significant and reliable to develop distribution maps with high predictive power. Our results highlight the importance of natural habitats for conservation efforts of these endemic species. A good conservation program should include the protection of suitable nesting areas and expand the protected areas network containing suitable habitats for both species in forest and coastal areas. We propose the use of predictive modelling tools to strengthen conservation actions not only for rare raptors but for the 238 endemic and threatened birds of the Neotropics with scarce data, small population sizes, restricted distributions and often specialist habits

Recomendaciones de manejo usando análisis de viabilidad poblacional del berrendo peninsular endémico

A case study on the viability of small populations with a restricted distribution and reduction in habitat quality is addressed using the peninsular pronghorn (Antilocapra americana peninsularis) of Baja California Peninsula, Mexico. The present size of its wild population is less than 250 individuals, being in an IUCN Critically Endangered status. Captive management of peninsular pronghorn began in 1998 in El Vizcaino Desert with 22 founders. We predicted future trends in the pronghorn population, and assessed the risk of extinction through population viability analysis (PVA) using VORTEX. Deterministic and stochastic factors designed to simulate human activity on the landscape were evaluated for their impact on this endemic taxon. The concept of supportive breeding was assessed. The results of PVA simulations indicate that removal of founder animals to initiate the captive breeding did not significantly reduce the viability of the wild population. However, a population size <100 individuals greatly increase the risk of extinction. Also, one of the most important factors for the viability of the peninsular pronghorn population is the survival of fawns. The risk of extinction can be significantly reduced using supportive breeding. We propose that the likelihood of successful population management of peninsular pronghorn could be increased establishing a number of subpopulations across the species’ historic range and, even more importantly, the establishment of ecologically functional connections between these subpopulations to create a proper metapopulation. Captive breeding can be an important factor to decrease the probability of extinction of this subspecies. Key Words: Antilocapra americana, endangered, management, PVA, recovery.Se evaluó el riesgo de extinción de la población del berrendo peninsular (Antilocapra americana peninsularis) en la península de Baja California, México que presenta distribución restringida y deterioro en la calidad de su hábitat. En el año 2000, el tamaño de la población silvestre del berrendo peninsular era menor a 250 individuos. Se desarrolló un análisis de viabilidad de poblaciones (PVA) usando Vortex, que incluyó variables determinísticas y estocásticas, e información de 25 años para proyectar cambios en la población, y evaluar su riesgo de extinción. Con el PVA se evaluó el concepto de Reproducción de Apoyo. En 1998 se inició el manejo en cautiverio del berrendo peninsular con 22 animales fundadores. Los modelos sugirieron que una población de menos de 100 individuos incrementa considerablemente el riesgo de extinción, siendo uno de los factores más importantes para la viabilidad de la población la sobrevivencia de las crías. Se propone que el éxito del manejo de la población del berrendo peninsular puede incrementarse estableciendo subpoblaciones dentro de su rango histórico de distribución con una perspectiva metapoblacional donde se conecten las subpoblaciones. Y se concluye que la reproducción en cautiverio puede ser un factor importante para disminuir la probabilidad de extinción de esta subespecie.

Ectoparasites associated with a Great Horned Owl nesting population in fragmented landscape of Baja California peninsula, México

Ectoparasites are important in avian host population because they can affect health condition, regulate population dynamics and alter interspecific competition. Studies of ectoparasites in wild raptors are scarce and even few have been made in owls. This is the first study of the prevalence and intensity of ectoparasites in Great Horned Owl (Bubo virginianus) fledglings. We studied ectoparasites on fledglings from nests in a fragmented arid landscape at Baja California peninsula, during the breeding seasons of 2015 and 2017. The fledglings of 40 days of age were handled and taken from their nests for the collection of ectoparasites. A total of 81 epizoic species were collected from 36 nestlings from 15 nests, distributed in five orders: Diptera (Icosta americana); Hemiptera (Cimicidae gen. sp.); Phthiraptera (Neohaematopinus sciurinus, Colpocephalum pectinatum); Siphonaptera (Orchopea sp.) and Mesostigmata (Ornihtonysus sylviarum). Likewise, one species of chewing lice (n=5) (Geomydoecus telli) and one species of feather mite (n=7) were also recorded associated with the Great Horned Owl. Five species were hematophagous parasites. Louse fly I. americana and chewing louse C. pectinatum showed the highest levels of prevalence (26.5% and 20.6% respectively), while the hematophagous feather mite Ornihtonysus silviarum presented the higher mean intensity in only one nest (15.5). The flea Orchopea sp. and the chewing louse G. telli and sucking louse N. sciurinus exhibited the lowest values of prevalence and mean intensity; these species have been recorded in association mainly with rodents, so probably they could have been transmitted to the owls when they were captured as preys and taken into their nest. Additionally a bug (Cimicidae gen. sp.) was found in one host. Colpocephalum pectinatum is the first recorded from Great Horned owl, such as new host. The abundance of ectoparasites in one owl nest was independent of their abundance in neighbor nests (Moran´s I = 0.010; z = 0.16, P > 0.05). We discuss the implications of ectoparasitism for a Great Horned owl population in fragmented habitat of the Baja California arid desert.Los parásitos juegan un papel importante en la historia de vida de sus hospederos porque pueden afectar la salud, regular la dinámica poblacional e inclusive alterar la competición inter-especifica. Bajo ciertas condiciones de deterioro del hábitat, como la fragmentación, puede aumentar los niveles de infestación y en consecuencia tener efectos negativos más marcados en los hospederos. Este es el primer estudio de la prevalencia e intensidad de ectoparásitos en volantones de Búho Cornudo Bubo virginianus. Evaluamos los ectoparásitos en pollos de nidos situados en un paisaje árido fragmentado de la península de Baja California. Los pollos casi volantones de 40 días de edad fueron tomados del nido durante las temporadas reproductivas del 2015 y 2017, para realizar la colecta de ectoparásitos y regresarlos posteriormente. Se colectaron 81 ectoparásitos de 36 polluelos en 15 nidos. Fue registrada una infestación del 61% (n=22) con ocho especies (H = 1.56), cinco de las cuales fueron parásitos hematófagos. Los ectoparásitos estuvieron distribuidos en cinco órdenes; Diptera (Icosta americana); Hemiptera (Cimicidae gen. sp.); Phthiraptera (Neohaematopinus sciurinus, Colpocephalum pectinatum); Siphonaptera (Orchopea sp.), y Mesostigmata (Ornihtonysus sylviarum). También se registró una especie de piojo masticador (n=5) (Geomydoecus telli) y una de ácaro de plumas (n=7) asociados con el búho cornudo. La mosca piojo I. americana y el piojo masticador C. pectinatum presentaron alta prevalencia (26.5% y 20.6% respectivamente), mientras que el ácaro hematófago O. silviarum presentó la más alta intensidad media en un sólo nido (15.5). La pulga Orchopea sp., y los piojos, masticador G. telli y succionador N. sciurinus, fueron registros raros y exhibieron los valores más bajos de prevalencia e intensidad media; estas especies se han registrado en asociación principalmente a roedores, así que probablemente se transmitieron a los pollos al llevar presas de roedores al nido del búho. Adicionalmente una chinche Cimicidae gen. sp., se encontró en un huésped. Colpocephalum pectinatum es primer registro para el Búho cornudo como hospedero. La abundancia de ectoparásitos en un nido de búho fue independiente de la abundancia de nidos cercanos (Moran´s I = 0.010; z = 0.16, P > 0.05). Se discuten las implicaciones que tienen los ectoparásitos en una población del Búho cornudo en un hábitat fragmentado del desierto árido de Baja California

Cotorra argentina (Myiopsitta monachus), especie anidando con éxito en el sur de la Península de Baja California

Se presenta información sobre la presencia y abundancia así como evidencias de anidación de la cotorra Argentina (Myiopsittamonachus), especie exótica en el sur de la península de Baja California. La cotorra fue registrada por primera vez en noviembre de 2012 en el poblado de Chametla, 7 km al norte de la ciudad de La Paz. Desde entonces y hasta el día de hoy, el perico ha incrementado su abundancia en 10 veces su población inicial. Reportamos actividad de anidación, entre mayo y agosto de 2013 y mayo -agosto 2014. Los nidos fueron construidos sobre la palma de abanico (Washingtonia robusta, 75%) y palma de coco (Cocos nucifera, 25%). Se les observó alimentándose de frutos de palma datilera (Phoenix dactylifera), mezquite (Prosopis sp.), tamarindo (Tamarindus indica), guamúchil (Pithecellobium dulce) y otatave (Vallesia glabra), así como de restos de comida provistos por la gente. Se discuten las posibles implicaciones de la presencia deesta especie exótica en la región.

Efectos de la fragmentación del matorral desértico sobre poblaciones del aguililla cola-roja y el cernícalo americano en Baja California Sur, México

To evaluate the effects of desert scrub habitat fragmentation on resident and migrant populations of Red-tailed Hawk and American Kestrel, we conducted monthly raptor road surveys during two years, 2008 and 2009, in natural desert scrub areas and in fragmented areas of Baja California Sur, México. We recorded 1,806 records of the two raptor species. The most common was the American Kestrel with 1,164 (64.4%) records (51% found in fragmented area, and 49% in natural area). The Redtailed Hawk accounted for 642 records (35.6%) (70% in fragmented areas, and 30% in natural areas). The relative abundance and density of Red-tailed Hawk in the spring and summer were similar between areas, but in the fall and winter the abundances and densities were much higher in fragmented areas. The abundance of American Kestrel was similar between areas in all seasons. Density was similar between areas in spring, summer and winter but it was higher in fragmented areas in the fall. The desert scrub of Baja California Sur and fragmented areas inside a cultivated agricultural matrix is an important habitat for migrant populations of both raptor species as indicated by the results of the fall and winter seasons. We discuss on the raptor species tolerance to habitat changes (threshold concept) as a function of their body size and habitat specialization (for nesting and foraging activities) and on the effects of fragmentation of desert scrub habitats on the abundance and density of the Red-tailed Hawk and American Kestrel in southern Baja California peninsula.Para evaluar el efecto de la fragmentación del desierto sobre especies de poblaciones residentes y migratorias, durante 2008 y 2009 se realizaron muestreos mensuales de dos especies de aves rapaces, el aguililla cola-roja Buteo jamaicensis y el cernícalo americano Falco sparverius. Los muestreos se realizaron en áreas naturales continuas y en áreas fragmentadas por actividad agrícola en el matorral desértico de Baja California Sur. En total se registraron en 1,806 ocasiones las dos especies. La más común fue el cernícalo americano con 1,164 (64.4%) registros (los cuales fueron 51% en área fragmentada y 49% área natural) y el aguililla cola-roja con 642 registros (35.6%) (70% en área fragmentada y 30% en área natural). Se estimaron las abundancias relativas y la densidad, las cuales no variaron durante la primavera y verano para el aguililla cola-roja, pero sus abundancias y densidades fueron mayores en las áreas fragmentadas durante otoño e invierno. Por otro lado, la abundancia del cernícalo americano fue similar entre áreas en todas las temporadas del año, mientras que la densidad fue similar en primavera, verano e invierno, pero fue mayor en el área fragmentada durante el otoño. Se encontró que el matorraldesértico y sus áreas fragmentadas dentro de una matriz agrícola en Baja California Sur es un hábitat importante para las poblaciones migratorias de ambas especies de rapaces. Se discute sobre la tolerancia de las dos especies en función de su tamaño y selección de hábitat para anidar y forrajear, así como los efectos de la fragmentación del desierto sobre su abundancia y densidad en el sur de la península de Baja California

Evidencia de cleptoparasitismo del caracara común (Caracara cheriway) sobre el alcaudón verdugo (Lanius ludovicianus)

Kleptoparasitism of Crested caracara on Loggerhead shrike was recorded on July 18, 2013 in a fragmented habitat of desert Baja California Sur. An adult caracara kleptoparasitized a mammal prey (Peromyscus eva) that a loggerhead shrike had impaled in a shrub, an Adam´s tree. This is the first record of kleptoparasitism of a 1050-1300 g raptor on a small passerine bird (45 g).Kleptoparasitism of Crested caracara on Loggerhead shrike was recorded on July 18, 2013 in a fragmented habitat of desert Baja California Sur. An adult caracara kleptoparasitized a mammal prey (Peromyscus eva) that a loggerhead shrike had impaled in a shrub, an Adam´s tree. This is the first record of kleptoparasitism of a 1050-1300 g raptor on a small passerine bird (45 g)

Islands in the desert for cavity‐nesting bees and wasps: Ecology, patterns of diversity, and conservation at oases of Baja California Peninsula

Aims The oases of Baja California Peninsula (BCP) have been proposed as important hotspots of biodiversity that hold an exceptional richness in the middle of desert conditions. We tested the effect of habitat and anthropogenic disturbance on communities of cavity-nesting taxa, with specific emphasis on bees, wasps, and their natural enemies. Methods In oases of BCP and desert neighbor environments, trap-nesting taxa were evaluated in response to factors affecting the nest abundance, richness, and community structure. We used statistical models to find correlates of nest abundance and patterns of diversity, as well as ecological analyses to determine the effect of habitat and human disturbance on species diversity and community structure. Results Solar irradiation, distance to a perennial waterbody and relative humidity influenced the presence of nests, number of brood cells, and parasitism. In general, abundance, species richness, and parasitism were higher in oases, especially in those with less human disturbance. Bees did not discriminate between oases and deserts to nest, whereas mud-daubing wasps were more dependent of oases. The degree of anthropogenic disturbance did not affect the occurrence of parasitism, but it had an adverse effect on the parasitism intensity (number of attacked cells). The community structure was more complex and even in oases and low-disturbed sites. The similarity between sites did not exceed 30%, and the proportion of shared species between oases and deserts varied from 2.7% to 26.6%. Main conclusions The oases of Baja California are functioning as mesic islands in the desert, each oasis hosting a unique community of cavity-nesting taxa. About 65% of the nests and 50% of species occurred exclusively in the oasis. Thus, cavity-nesting species that depend on mesic conditions could be threatened if the oases of BCP disappear in the future. Local conditions in the oases and deserts of the BCP are shaping the community structure. However, large-scale factors such as climate can influence the seasonality and occurrence of species within the community of cavity-nesting dwellers. Since habitat loss and fragmentation can degrade the oases' functionality, strategies to maintain the ecosystem services of pollination and biological control should be included in the conservation programs of these fragile habitats.Consejo Nacional de Ciencia y TecnologiaConsejo Nacional de Ciencia y Tecnologia (CONACyT) [273254]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Localized extinction of an arboreal desert lizard caused by habitat fragmentation

We adopted a species' perspective for predicting extinction risk in a small, endemic, and strictly scansorial lizard (Urosaurus nigricaudus), in an old (∿60. year) and highly fragmented (8% habitat remaining) agricultural landscape from the Sonoran Desert, Mexico. We genotyped 10. microsatellite loci in 280 individuals from 11 populations in fragmented and continuous habitat. Individual dispersal was restricted to less than 400. m, according to analyses of spatial autocorrelation and spatially explicit Bayesian assignment methods. Within this scale, continuous areas and narrow washes with native vegetation allowed high levels of gene flow over tens of kilometers. In the absence of the native vegetation, cleared areas and highways were identified as partial barriers. In contrast, outside the scale of dispersal, cleared areas behaved as complete barriers, and surveys corroborated the species went extinct after a few decades in all small (less than 45. ha), isolated habitat fragments. No evidence for significant loss of genetic diversity was found, but results suggested fragmentation increased the spatial scale of movements, relatedness, genetic structure, and potentially affected sex-biased dispersal. A plausible threshold of individual dispersal predicted only 23% of all fragments in the landscape were linked with migration from continuous habitat, while complete barriers isolated the majority of fragments. Our study suggested limited dispersal, coupled with an inability to use a homogeneous and hostile matrix without vegetation and shade, could result in frequent time-delayed extinctions of small ectotherms in highly fragmented desert landscapes, particularly considering an increase in the risk of overheating and a decrease in dispersal potential induced by global warming. © 2012 Elsevier Ltd.Peer Reviewe

Ampliación en la distribución geográfica y reproductiva del milano cola blanca Elanus leucurus en el centro-oriente de México.

We report the distribution and reproduction of the White-tailed kite Elanus leucurus in Puebla and Tlaxcala, giving confirmation of its resident breeding status for Puebla and as a new record for Tlaxcala.Se reporta la distribución y reproducción del milano cola blanca Elanus leucurus en Puebla y Tlaxcala, confirmando su estatus de residente reproductor para Puebla, con nuevo registro para Tlaxcala