Basin Wildlife Research Articles

Feeding observations of a Turkey Vulture (Cathartes aura) and a Lesser Yellow-headed Vulture (C. burrovianus) in Belize

I present 2 noteworthy foraging observations of a Lesser Yellow-headed Vulture (Cathartes burrovianus) and a Turkey Vulture (C. aura) in Crooked Tree Wildlife Sanctuary and Cockscomb Basin Wildlife Sanctuary, Belize, respectively. I observed a Lesser Yellow-headed Vulture successfully capture a live fish from the water and a Turkey Vulture feeding on feces of neotropical otter (Lontra longicaudis) along a river. To my knowledge, these observations represent novel reports for each species, and contribute to the understanding of the breadth of foraging behavior of cathartid vultures.

Generating indicator species for bird monitoring within the humid forests of northeast Central America.

The use of indicator species can simplify bird monitoring by reducing the level of specialized skills needed, which increases the potential pool of participants and reduces training costs and complexity. To facilitate monitoring in the humid forests of northeast Central America, we conducted point count surveys for birds across gradients of disturbance in the Cockscomb Basin Wildlife Sanctuary, Belize, and analyzed the association of bird species with remotely sensed metrics of forest condition and anthropogenic disturbance using indicator species analysis. Twenty species exhibited significant associations with one or more of these metrics. We propose six species as indicators for anthropogenic disturbance based on our criteria of being associated with anthropogenically disturbed sites, or anthropogenically disturbed and riparian sites with no explicit mention in the literature of an obligate association with riparian habitats, or association of remotely sensed metrics that appeared to reflect disturbance: yellow-olive flycatcher, red-legged honeycreeper, dusky antbird, blue ground dove, buff-throated saltator, and brown jay. We propose the keel-billed motmot as an indicator of undisturbed forest based on its association with forested sites in our analyses. Green shrike vireo, collard trogon, rufous-tailed jacamar, and rufous piha were associated with a specific elevational range but not associated with disturbance, so upward shifts in elevation that might indicate response to climate change would not be confounded with habitat disturbance or degradation. This exercise yielded a much-reduced list of monitoring targets, which will greatly reduce the cost and complexity of forest bird monitoring in the region, as well as reducing barriers to participation.

Spatially explicit capture recapture density estimates: Robustness, accuracy and precision in a long-term study of jaguars (Panthera onca).

Camera trapping is the standard field method of monitoring cryptic, low-density mammal populations. Typically, researchers run camera surveys for 60 to 90 days and estimate density using closed population spatially explicit capture-recapture (SCR) models. The SCR models estimate density, capture probability (g0), and a scale parameter (σ) that reflects ranging behaviour. We used a year of camera data from 20 camera stations to estimate the density of male jaguars (Panthera onca) in the Cockscomb Basin Wildlife Sanctuary in Belize, using closed population SCR models. We subsampled the dataset into 276 90-day sessions and 186 180-day sessions. Estimated density fluctuated from 0.51 to 5.30 male jaguars / 100 km2 between the 90-day sessions, with comparatively robust and precise estimates for the 180-day sessions (0.73 to 3.75 male jaguars / 100 km2). We explain the variation in density estimates from the 90-day sessions in terms of temporal variation in social behaviour, specifically male competition and mating events during the three-month wet season. Density estimates from the 90-day sessions varied with σ, but not with the number of individuals detected, suggesting that variation in density was almost fully attributable to changes in estimated ranging behaviour. We found that the models overestimated σ when compared to the mean ranging distance derived from GPS tracking data from two collared individuals in the camera grid. Overestimation of σ when compared to GPS collar data was more pronounced for the 180-day sessions than the 90-day sessions. We conclude that one-off ('snap-shot') short-term, small-scale camera trap surveys do not sufficiently sample wide-ranging large carnivores. When using SCR models to estimate the density from these data, we caution against the use of poor sampling designs and/or misinterpretation of scope of inference. Although the density estimates from one-off, short-term, small-scale camera trap surveys may be statistically accurate within each short-term sampling period, the variation between density estimates from multiple sessions throughout the year illustrate that the estimates obtained should be carefully interpreted and extrapolated, because different factors, such as temporal stochasticity in behaviour of a few individuals, may have strong repercussions on density estimates. Because of temporal variation in behaviour, reliable density estimates will require larger samples of individuals and spatial recaptures than those presented in this study (mean +/- SD = 14.2 +/- 1.2 individuals, 37.7 +/- 4.7 spatial recaptures, N = 276 sessions), which are representative of, or higher than published sample sizes. To satisfy the need for larger samples, camera surveys will need to be more expansive with a higher density of stations. In the absence of this, we advocate longer sampling periods and subsampling through time as a means of understanding and describing stability or variation between density estimates.

Population genetic structure and habitat connectivity for jaguar (Panthera onca) conservation in Central Belize

BackgroundConnectivity among jaguar (Panthera onca) populations will ensure natural gene flow and the long-term survival of the species throughout its range. Jaguar conservation efforts have focused primarily on connecting suitable habitat in a broad-scale. Accelerated habitat reduction, human-wildlife conflict, limited funding, and the complexity of jaguar behaviour have proven challenging to maintain connectivity between populations effectively. Here, we used non-invasive genetic sampling and individual-based conservation genetic analyses to assess genetic diversity and levels of genetic connectivity between individuals in the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We used expert knowledge and scientific literature to develop models of landscape permeability based on circuit theory with fine-scale landscape features as ecosystem types, distance to human settlements and roads to predict the most probable jaguar movement across central Belize.ResultsWe used 12 highly polymorphic microsatellite loci to identify 50 individual jaguars. We detected high levels of genetic diversity across loci (HE = 0.61, HO = 0.55, and NA = 9.33). Using Bayesian clustering and multivariate models to assess gene flow and genetic structure, we identified one single group of jaguars (K = 1). We identified critical areas for jaguar movement that fall outside the boundaries of current protected areas in central Belize. We detected two main areas of high landscape permeability in a stretch of approximately 18 km between Sittee River Forest Reserve and Manatee Forest Reserve that may increase functional connectivity and facilitate jaguar dispersal from and to Cockscomb Basin Wildlife Sanctuary. Our analysis provides important insights on fine-scale genetic and landscape connectivity of jaguars in central Belize, an area of conservation concern.ConclusionsThe results of our study demonstrate high levels of relatively recent gene flow for jaguars between two study sites in central Belize. Our landscape analysis detected corridors of expected jaguar movement between the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We highlight the importance of maintaining already established corridors and consolidating new areas that further promote jaguar movement across suitable habitat beyond the boundaries of currently protected areas. Continued conservation efforts within identified corridors will further maintain and increase genetic connectivity in central Belize.

Open population maximum likelihood spatial capture-recapture.

Open population capture-recapture models are widely used to estimate population demographics and abundance over time. Bayesian methods exist to incorporate open population modeling with spatial capture-recapture (SCR), allowing for estimation of the effective area sampled and population density. Here, open population SCR is formulated as a hidden Markov model (HMM), allowing inference by maximum likelihood for both Cormack-Jolly-Seber and Jolly-Seber models, with and without activity center movement. The method is applied to a 12-year survey of male jaguars (Panthera onca) in the Cockscomb Basin Wildlife Sanctuary, Belize, to estimate survival probability and population abundance over time. For this application, inference is shown to be biased when assuming activity centers are fixed over time, while including a model for activity center movement provides negligible bias and nominal confidence interval coverage, as demonstrated by a simulation study. The HMM approach is compared with Bayesian data augmentation and closed population models for this application. The method is substantially more computationally efficient than the Bayesian approach and provides a lower root-mean-square error in predicting population density compared to closed population models.

Long term monitoring of jaguars in the Cockscomb Basin Wildlife Sanctuary, Belize; Implications for camera trap studies of carnivores.

In this study, we estimate life history parameters and abundance for a protected jaguar population using camera-trap data from a 14-year monitoring program (2002–2015) in Belize, Central America. We investigated the dynamics of this jaguar population using 3,075 detection events of 105 individual adult jaguars. Using robust design open population models, we estimated apparent survival and temporary emigration and investigated individual heterogeneity in detection rates across years. Survival probability was high and constant among the years for both sexes (φ = 0.78), and the maximum (conservative) age recorded was 14 years. Temporary emigration rate for the population was random, but constant through time at 0.20 per year. Detection probability varied between sexes, and among years and individuals. Heterogeneity in detection took the form of a dichotomy for males: those with consistently high detection rates, and those with low, sporadic detection rates, suggesting a relatively stable population of ‘residents’ consistently present and a fluctuating layer of ‘transients’. Female detection was always low and sporadic. On average, twice as many males than females were detected per survey, and individual detection rates were significantly higher for males. We attribute sex-based differences in detection to biases resulting from social variation in trail-walking behaviour. The number of individual females detected increased when the survey period was extended from 3 months to a full year. Due to the low detection rates of females and the variable ‘transient’ male subpopulation, annual abundance estimates based on 3-month surveys had low precision. To estimate survival and monitor population changes in elusive, wide-ranging, low-density species, we recommend repeated surveys over multiple years; and suggest that continuous monitoring over multiple years yields even further insight into population dynamics of elusive predator populations.

Optimizing regulatory requirements to aid in the implementation of compensatory mitigation

Optimizing regulatory requirements to aid in the implementation of compensatory mitigation

Long-term Land Use and Land Cover Changes Affected by the Conservation Reserve Program in the Minnesota River Valley

The Conservation Reserve Program (CRP) is a cost-share and rental payment program signed into law byPresident Reagan in 1985 and administered by the Farm Service Agency (FSA) under the United StateDepartment of Agriculture (USDA). CRP aims to counteract erosion and protect the environment by encouragingagricultural landowners to convert highly erodible cropland and other environmentally sensitive lands to nativeor alternative permanent vegetative cover through the implementation of 10-year contracts paying annual rents.CRP has been actively implemented since the enactment of the Food Security Act of 1985. Re-authorized byCongress in 1996 with major modifications, the CRP has been renewed with minor alterations several times. In1998, the joint state/federal Conservation Reserve Enhancement Program (CREP) targeted the long-termretirement of an additional 40,469 ha (100,000 acres) of agricultural land in the Minnesota River basin toenhance water quality and wildlife habitat through permanent conservation easements.This research examines land use change from 1985 to 2013 in the Minnesota River Valley beginning with an eraof no long-term set-asides to the current era with two active long-term set-aside conservation reserve programs.Multi-temporal remote sensing images from 1985, 1995, 2005 and 2013 were analyzed to map the land usechanges in response to the CRP policy alterations. The results revealed more than 36,000 ha (89,000 acres)cropland have been converted to grassland or forest during this 28-year span. A persistent drop in croplandoccurred in spite of rising corn and soybean prices since 2002 associated with Minnesota’s biofuel industry andincreased foreign demand for these commodities, which indicates that the long-term nature of the CRP andCREP contracts are critical for maintaining the conversions of cropland to grassland or forest cover whileproviding stable farm income.

Scrape-marking behavior of jaguars (Panthera onca) and pumas (Puma concolor)

Marking behaviors of jaguars (Panthera onca) and pumas (Puma concolor) were investigated by linking sign from transect surveys to species, sex, and individual detected by camera traps along trails in the Cockscomb Basin Wildlife Sanctuary, Belize. The most commonly encountered big-cat signs were scrape marks. These were produced by cats raking the ground with their feet. Scrapes were associated more strongly with presence of male pumas than with female pumas or jaguars of either sex. Scats found in scrapes were genotyped to species level and indicated that jaguars produced larger scrapes than pumas and that pumas were more likely to scrape with their hind feet than with front feet. Scrapes were spatially clustered along trails, indicating that individuals scrape in response to other scrapes in the same area. High scraping frequencies were not associated with the presence of specific individuals, suggesting that scrape-marking behavior does not signal dominance in this area.

Jaguar and puma activity patterns in relation to their main prey

Activity patterns of top predators are adapted for efficient predation, whereas their prey must contend with the conflicting demands of acquiring resources and avoiding predators. Here we analyse the activity of jaguars ( Panthera onca) and pumas ( Puma concolor) in relation to their most important prey species, armadillos ( Dasypus novemcinctus) and pacas ( Agouti paca) respectively, in the Cockscomb Basin Wildlife Sanctuary, Belize using large-scale camera-trap data. Jaguars and pumas have similar 24 h activity patterns as armadillos and pacas, both burrow-dwelling species, and negligible overlap with less frequently consumed prey species such as red brocket deer ( Mazama americana) and peccaries. Activity of armadillos and pacas varied with moon phase, with reduced activity during periods of brighter illumination, perhaps as a predator-avoidance strategy. Across the study area, moon phase had no overall influence on jaguar and puma activity; however at locations associated with armadillos, jaguar activity declined with brighter illumination, perhaps indicating a shift to alternative prey during full moon when armadillos avoided foraging above ground. No such relationship was found for pumas and moon phase at locations associated with pacas.

A New Record Size for the Northern Desert Nightsnake (Hypsiglena chlorophaea deserticola)

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Research, Monitoring, and Evaluation of Fish and Wildlife Restoration Projects in the Columbia River Basin: Lessons Learned and Suggestions for Large-Scale Monitoring Programs

Abstract The year 2006 marked two milestones in the Columbia River Basin and the Pacific Northwest region's efforts to rebuild its once great salmon and steelhead runs—the 25th anniversary of the creation of the Northwest Power and Conservation Council and the 10th anniversary of an amendment to the Northwest Power Act that formalized scientific peer review of the council's Fish and Wildlife Program and its varied individual projects. The authors of this article served as peer reviewers in the last decade. Restoration efforts in the Columbia River constitute a massive long-term attempt at fisheries and ecosystem restoration. In this article we examine some of the lessons we learned in reviewing the research, monitoring, and evaluation efforts of projects and their effects on advancing knowledge (i.e., adaptive management) in the Columbia River Basin Fish and Wildlife Program, one of the most ambitious and expensive long-term ecological restoration programs in the United States.

Cockscomb Revisited: Jaguar Diet in the Cockscomb Basin Wildlife Sanctuary, Belize1

ABSTRACTThe Cockscomb Basin Wildlife Sanctuary, Belize was established in 1986 following Rabinowitz and Nottingham's 1986 study on jaguar diet and distribution. In 2002, we reexamined jaguar diet following two decades of mitigated human hunting of jaguar prey. We observed high overlap between historical and current jaguar diet constructs. Nine‐banded armadillo remained the most frequently consumed prey item. However, collared peccary consumption increased by nearly 20 percent while dietary breadth decreased by 60 percent presumably reflecting increased prey availability following reduced human hunting pressure.

Phytochemical and mineral components of foods consumed by black howler monkeys (Alouatta pigra) at two sites in Belize

We analyzed the chemical composition of the diets of eight groups of free-ranging black howler monkeys (Alouatta pigra) in Belize, Central America. The study groups were located in two different forests: the Community Baboon Sanctuary (CBS) and the Cockscomb Basin Wildlife Sanctuary (CBWS). Two of the study groups were translocated from the CBS to CBWS 3 months into the study, and we compared the diets of groups in the two forests. Young and mature leaves, fruits, flowers, and fig samples (n = 144) were analyzed for water content, crude and available protein, fiber, simple sugars, and minerals. Statistically significant differences were found among the plant parts in all measures except acid-detergent fiber. Dietary foliage in CBS was higher in water content and protein but lower in simple sugars than dietary foliage in CBWS. We suggest that changes in the selection of plant parts by primates may be related to differences in the nutritional content of those parts. These data may be useful in developing optimal diets for captive howler monkeys. Zoo Biol 19:95–109, 2000. © 2000 Wiley-Liss, Inc.