David Romo

TEMPORAL AND SPATIAL PATTERNS OF MACAW ABUNDANCE IN THE ECUADORIAN AMAZON

Abstract Although macaws are arguably the most widely recognized species of bird from Neotropical rainforests, little is known of their basic biology or demography in the wild. In Ecuador, as in other Neotropical countries, it is suspected that several species of macaw are declining in response to human activity and habitat alteration but there is little hard data supporting this supposition. In this paper, we present one full year of data on macaw populations from a relatively pristine site in the Ecuadorian Amazon, and compare this site to two other sites with intermediate and relatively high levels of human activity. At Tiputini Biodiversity Station, a pristine terra-firme forest, macaws were more common in the dry season than in the wet season. This pattern is the opposite of that recently reported for seasonally inundated forests in Peru, suggesting that macaws may make large-scale, seasonal movements across habitat types. We employed the same sampling methodology for shorter periods of time at Sacha Lodge, characterized by intermediate levels of human activity, and at Jatun Sacha Biological Station, characterized by relatively high levels of human activity and habitat degradation. We recorded an intermediate number of macaws at Sacha Lodge, and the lowest densities at Jatun Sacha. Three groups of indicator taxa sampled at all three sites showed a similar pattern. These data provide a baseline for future demographic studies of macaws in the Ecuadorian Amazon and lend tentative support to the idea that macaw population declines may be linked to human activity and habitat alteration. Patrones Temporales y Espaciales de Abundancia de Guacamayos en la Amazonía Ecuatoriana Resumen. A pesar de que los guacamayos son en principio el grupo de especies de aves más conspicuo de los bosques neotropicales, muy poco se sabe sobre su biología básica y demografía en estado silvestre. En Ecuador, como en otros países neotropicales, se sospecha que algunas especies de guacamayos están desapareciendo en respuesta a la actividad humana y a la alteración del hábitat, aunque hay muy poca información que sustente esta suposición. En este trabajo, presentamos información sobre la demografía de los guacamayos obtenida durante un período de un año en un lugar relativamente prístino de la amazonía ecuatoriana, y lo comparamos con dos lugares que poseen niveles intermedios y altos de alteración humana. En la Estación de Biodiversidad Tiputini, un lugar con bosques de tierra firme en estado relativamente prístino, los guacamayos fueron más comunes en la temporada seca que en la temporada lluviosa. Este patrón es opuesto a lo reportado en bosques estacionalmente inundados en Perú, sugiriendo que los guacamayos podrían realizar desplazamientos estacionales a gran escala a través de diferentes tipos de hábitat. Nosotros empleamos la misma metodología de muestreo durante períodos más cortos de tiempo en Sacha Lodge, un lugar caracterizado por un nivel intermedio de impacto humano, y en la Estación Biológica Jatun Sacha, caracterizada por niveles de impacto humano y alteración de hábitat relativamente altos. Registramos un número intermedio de guacamayos en Sacha Lodge y densidades bajas en la Estación Biológica Jatun Sacha. Otros tres grupos de indicadores taxonómicos muestreados en los tres lugares visitados mostraron un patrón similar. Esta información provee una línea de base para futuros estudios demográficos de los guacamayos en la amazonía ecuatoriana y respalda de modo tentativo la idea de que la disminución de las poblaciones de guacamayos podría estar relacionada con la actividad humana y la alteración del hábitat.

Spatial and temporal activity patterns of ocelots Leopardus pardalis in lowland forest of eastern Ecuador

Ocelots (Leopardus pardalis) are common in lowland forests of Amazonia. We used camera traps to document the occurrence and activity of ocelots at a site in eastern Ecuador during 2005–2012 (15,058 trap-days). We accumulated 384 independent images of 16 males (147 images), 19 females (234 images), and 3 not assigned to individual or sex. Individuals varied in number of images (1 to > 50), number of camera locations (1–8), and number of months from first to last image (1–85). Photographic rate varied across years, from 15.3 to 29.9/1,000 trap-days in 2006 and 2010, respectively. Males and females were primarily active at night and showed similar hourly patterns of activity. Up to 3 individual males and 4 individual females were recorded at different camera locations each year. Resident males typically were photographed at more locations (mean of 4.1) than females (mean of 3.2). Results indicate that multiple ocelots, of both sexes, may be found within a relatively small (∼650 ha) area of lowland forest in eastern Ecuador and emphasize the importance of the region for conservation of ocelots and other species.

Ocelot (Leopardus pardalis) density in Eastern Ecuador based on capture–recapture analyses of camera trap data

The ocelot (Leopardus pardalis) is one of the most widespread neotropical felids but data on its distribution and population status in several countries are scarce. Here, we present estimates of density for lowland forest of eastern Ecuador. We used camera trap data and capture–recapture analyses to estimate ocelot density within a local area (~650 ha) within Yasuní Biosphere Reserve, recognized as a globally important area for biodiversity conservation. We estimated densities for dry and wet seasons (~2200 trap days total) using CAPTURE and both half and full values of the mean maximum distance moved (MMDM), as recommended for estimating densities. Estimated densities for the dry season were higher than during the wet season (dry: 41–74 ind/100 km2; wet: 32–52 ind/100 km2). Ocelots were captured more frequently at night than during the day and some individuals were captured more consistently in areas close to the Tiputini River. Density estimates for ocelots in the Yasuní region are somewhat higher than in other neotropical areas, but similar to other sites in the Amazon region. Based on the number of ocelots recorded in this relatively small study area, it is clear that the region is an important area for conservation. Further studies that take into account more complex estimates such as survival rates and migration as well as differences in growth and availability of resources could provide more evidence for the importance of this region.

Long-term variation in abundance of terrestrial mammals and birds in eastern Ecuador as measured by photographic rates and occupancy estimates

Long-term studies from undisturbed forests provide a baseline by which to assess impacts of human activities, including climate change, on vertebrate population dynamics in lowland tropical forests. We use cameratrap data from January to March, 2005 to 2015, to examine patterns of variation in numbers of images and occupancy (proportion of cameras where images of a species were obtained), variables that may reflect changes in abundance or activity patterns of terrestrial mammals and birds in an undisturbed lowland forest of eastern Ecuador. We accumulated 1,961 independent records of 31 mammal species and 427 images of 17 bird species during 5,547 trap-days. Number of mammal species ranged from 15 to 25 per year (107 to 466 images), whereas birds ranged from 3 to 11 species per year (10 to 122 images). Capture rates varied both among species and among years but showed no evidence of declines; populations of several species appeared to increase (Priodontes maximus, Dasypus novemcinctus, Pecari tajacu, and Dasyprocta fuliginosa). Similarly, occupancy rates provided no indication of consistent declines; occupancy rates increased significantly for D. fuliginosa, D. novemcinctus, and P. maximus. There was no indication that variation in either capture rates or occupancy was related to variation in large-scale climate trends as represented by the Southern Oscillation Index. Results suggest that populations of most species that are well sampled by camera traps have remained relatively stable over 11 years. Long-term studies from other regions in the tropics are needed to evaluate the generality of this pattern.

Effects of human traffic on use of trails by mammals in lowland forest of eastern Ecuador

Human activity can lead to changes in animal behavior and distribution patterns if the level of activity is high enough to cause disturbance. Both humans and other animals commonly use human-made trails in lowland tropical forest and, therefore, it is possible that use of trails by humans might affect the likelihood that animals would use those same trails. We investigated this possibility at a site in lowland forest of eastern Ecuador using camera traps to document numbers of people and numbers of other animals at a series of camera locations during January–March, 2014–2016. Human activity was higher on trails used by all visitors to the research station than on two research plots where human activity is restricted. Ungulates were the only group to show a strong negative relationship with human activity but only on trails open to all visitors; there was no apparent negative impact of human activity on research plots. Results suggest that the level of human activity along trails is not now causing negative impacts to most mammals but also that levels of activity should be monitored to ensure that any increase in human presence does not lead to negative responses by mammals.