Has the final countdown to wildlife extinction in Northern Central African Republic begun?

The wildlife populations of Northern Central African Republic experienced precipitous declines during the 1970s and 1980s. While anecdotes coming out of the region indicate that the wildlife populations remain under serious threat, little is known about their status. An aerial sample count was carried out in the Northern Central African Republic at the end of the dry season in June 2005 and covered an 85,000 km² complex landscape containing national parks, hunting reserves and community hunting areas. Results show a dramatic decline of wildlife since the previous survey in 1985. In 20 years, large mammals’ numbers decreased by 65%, probably because of poaching and diseases brought by illegal cattle transhumance. Elephant (Loxodonta africana) and Buffon kob (Kobus kob) populations showed the greatest decline (over 80% each), while buffalo (Syncerus caffer), roan antelope (Hippotragus equinus) and Giant Lord’s Derby Eland (Taurotragus derbianus) populations seem stable or increasing over these last 20 years. The analysis of the wildlife population distribution by status of the different types of protected areas (national parks, hunting areas) showed that individual encounter rates of elephant and buffalo were lower in national parks than in neighbouring hunting areas, while those for roan, giraffe (Giraffa camelopardalis) and Buffon kob were higher in the national parks.     

Leech removal is not the primary driver of basking behavior in a freshwater turtle

Leaving the water to bask (usually in the sun) is a common behavior for many freshwater turtles, with some species also engaging in “nocturnal basking.” Ectoparasite removal is an obvious hypothesis to explain nocturnal basking and has also been proposed as a key driver of diurnal basking. However, the efficacy of basking, day or night, to remove leeches has not been experimentally tested. Therefore, we examined the number of leeches that were removed from Krefft''s river turtles (Emydura macquarii krefftii) after experimentally making turtles bask at a range of times of day, durations, and temperatures. Turtles had high initial leech loads, with a mean of 32.1 leeches per turtle. Diurnal basking under a heat lamp for 3 hr at ~28°C significantly reduced numbers of leeches relative to controls. In diurnal trials, 90.9% of turtles lost leeches (mean loss of 7.1 leeches per turtle), whereas basking for 30 min under the same conditions was not effective (no turtles lost leeches, and all turtles were still visibly wet). Similarly, “nocturnal basking” at ~23°C for 3 hr was not effective at removing leeches. Only 18% of turtles lost leeches (one turtle lost one leech and another lost four leeches). Diurnal basking outdoors under direct sunlight for 20 min (mean temp = 34.5°C) resulted in a small reduction in leeches, with 50% of turtles losing leeches and an average loss of 0.7 leeches per turtle. These results indicate basking can remove leeches if temperatures are high or basking durations are long. However, it was only effective at unusually long basking durations in this system. Our data showed even the 20‐min period was longer than 70.1% of natural diurnal basking events, many of which took place at cooler temperatures. Therefore, leech removal does not appear to be the purpose of the majority of basking events.     

Encounter Rates From Road-Based Surveys of Rio Grande Wild Turkeys in Texas

ABSTRACT Traditional index-based techniques have indicated declines in Rio Grande wild turkey (Meleagris gallopavo intermedia; hereafter, wild turkey) populations across much of Texas, USA. However, population indices can be unreliable. Research has indicated that road-based surveys may be an efficacious technique for monitoring wild turkey populations on an ecoregion level. Therefore, our goal was to evaluate applicability of road-based distance sampling in the Cross Timbers, Edwards Plateau, Rolling Plains, and South Texas ecoregions of Texas. We conducted road-based surveys in each ecoregion during December 2007—March 2008 to estimate wild turkey flock encounter rates and to determine survey effort (i.e., km of roads) required to obtain adequate sample sizes for distance sampling in each ecoregion. With simulations using inflatable turkey decoys, we also evaluated effects of distance to a flock, flock size, and vegetative cover on turkey flock detectability. Encounter rates of wild turkey flocks from road-based surveys varied from 0.1 (95% CI = 0.0–0.6) to 2.2 (95% CI = 0.8–6.0) flocks/100 km surveyed. Encounter rates from surveys restricted to riparian communities (i.e., areas ≤1 km from a river or stream) varied from 0.2 (95% CI = 0.1–0.6) to 2.9 (95% CI = 1.5–6.7) flocks/100 km surveyed. Flock detection probabilities from field simulations ranged from 22.5% (95% CI = 16.3–29.8%) to 25.0% (95% CI = 13.6–39.6%). Flock detection probabilities were lower than expected in all 4 ecoregions, which resulted in low encounter rates. Estimated survey effort required to obtain adequate sample sizes for distance sampling ranged from 2,765 km (95% CI = 2,597–2,956 km) in the Edwards Plateau to 37,153 km (95% CI = 12,861–107,329 km) in South Texas. When we restricted road-based surveys to riparian communities, estimated survey effort ranged from 2,222 km (95% CI = 2,092–2,370 km) in the Edwards Plateau to 22,222 km (95% CI = 19,782–25,349 km) in South Texas.     

Effects of post-chilling temperature on growth and variegation in Solomon's Seal

Effects of temperature were studied on the current and following season's growth of shoots from chilled rhizomes of Variegated Solomon's Seal. The rate of progress to completed elongation of the aerial shoot in chilled plants increased linearly with increasing temperature up to 28°C (24 h mean). A post‐chilling thermal time of 658 ± 47°Cd (> ‐1.3°C) was required for aerial shoots to become fully extended. Temperatures of 28°C and 33°C accelerated aerial shoot senescence and decreased rhizome and root dry weights, as compared with 18°C and 23°C treatments. Leaf number and variegation were not affected by temperature treatments during current growth season and all plants produced 12–13 leaves with between 7% and 9% leaf area variegated. Leaf variegation, however, was significantly increased in plants that had been grown after chilling at 28°C during the preceding growing season. Proteins of approximately 26, 32 and 62 kDa were present in the green parts of leaves but not in the white parts.     

Estimating nests not present at the time of breeding surveys: an important consideration in assessing nesting populations

ABSTRACT.   Counts of nest starts are often used as indicators of the size of avian nesting populations, or of avian productivity. However, the accuracy of single or repeated counts of unmarked nests over time for estimating seasonal numbers of nests may be strongly affected by nest events that fall in between survey dates, or that occurred prior to or after the survey period. Accuracy may also be affected by uncertainty in the interpretation of counts due to overlap between starting and ending dates of asynchronous nests during the intervisit interval. To measure the combined magnitude of these effects on survey accuracy, we overlaid a monthly "survey" regime on known initiation and ending dates of 2055 nests of ciconiiform birds. Assuming all nests present on the date of simulated survey were counted, monthly surveys underestimated the true number of nest starts by 24–64%, depending on species and year. Using a simple model, we also demonstrate that accuracy does not increase much as survey frequency increases, and that significant estimation error can occur over a wide range of nest success values and degrees of asynchrony. We suggest that (1) these biases can be significant for surveys of many kinds of nesting birds including some territorial passerines, (2) this bias cannot be addressed by increasing survey frequency, and (3) the degree of renesting may be of critical interest for inferring breeding population size from nest count data. We suggest three possible approaches for modeling this error.     

Mist Net Effort Required to Inventory a Forest Bat Species Assemblage

Abstract: Little quantitative information exists about the survey effort necessary to inventory temperate bat species assemblages. We used a bootstrap resampling algorithm to estimate the number of mist net surveys required to capture individuals from 9 species at both study area and site levels using data collected in a forested watershed in northwestern California, USA, during 1996–2000. The mean number of simulated surveys required to capture individual species varied with species' rarity and ranged from 1.5 to 44.9. We retrospectively evaluated strategies to reduce required survey effort by subsampling data from 1996 to 1998 and tested the strategies in the field during 1999 and 2000. Using data from 1996 to 1998, the mean number of simulated surveys required to capture 8 out of 9 species was 26.3, but a 95% probability of capture required >61 surveys. Inventory efficiency, defined as the cumulative proportion of species detected per survey effort, improved for both the study area and individual sites by conducting surveys later in summer. We realized further improvements in study area inventory efficiency by focusing on productive sites. We found that 3 surveys conducted between 1 July and 10 September at each of 4 productive sites in this 10-km² study area resulted in the capture of 8 species annually. Quantitative estimation of the survey effort required to assess bat species occurrence improves the ability to plan and execute reliable, efficient inventories. Results from our study should be useful for planning inventories in nearby geographical areas and similar habitat types; further, the analytical methods we used to assess effort are broadly applicable to other survey methods and taxa.     

Effects of Precommercial Thinning on Snowshoe Hares in Maine

Abstract: Snowshoe hares (Lepus americanus) are an important prey species and a dominant herbivore across much of their North American range, and researchers have questioned the influences of forestry practices that alter habitat for hares and the potential community-level effects on carnivores. We examined the effects of precommercial thinning (PCT) from 1 to 11 years posttreatment on snowshoe hares. In the commercial forests of northern Maine, USA, we counted and cleared hare pellets twice a year during 2001 and 2002 on >46 km of pellet transects across 30 regenerating conifer stands (17 treated with PCT) previously treated with an aerial application of herbicide. We compared densities of snowshoe hare pellets among 3 development classes with (1 yr after thinning, 6 yr after thinning, and 11 yr after thinning) and without thinning (stands with a similar history of clearcut and herbicide treatment but no thinning). During both years, densities of hares were lower in stands treated with PCT than in similar unthinned stands across the 3 development classes and during both leaf-off and leaf-on seasons (P < 0.001). Within both thinned and unthinned stands, hare density was greatest in stands in the 1-year development class when compared to the 6-year and 11-year development classes, but a statistical difference (P = 0.048) among classes was evident only during leaf-off seasons. Precommercial thinning was associated with densities of snowshoe hares that were approximately half of those in similar unthinned stands up to at least 11 years posttreatment; however, thinned stands may retain densities of hares greater than stands managed using other forest harvesting regimes. Our results apply to core portions of stands with crop trees spaced at 1.8–2.4-m intervals following complete overstory removal and herbicide treatment. We advocate caution when applying our results to other thinning regimes or across broader spatial scales.     

Landscape Analysis of Bobcat Habitat in the Northern Lower Peninsula of Michigan

ABSTRACT Controversy over bobcat (Lynx rufus) management in the northern Lower Peninsula of Michigan (NLP), USA, stimulated a need for information on the distribution of Michigan bobcats. From March 2003 to October 2004, we conducted a radiotelemetry and scentstation survey study of bobcats in the NLP. We developed a spatial model to predict bobcat distribution throughout the NLP based on bobcat area requirements, habitat and landscape variables derived from remotely sensed land-cover data, and a multivariate distance statistic. Bobcat 50% minimum convex polygon core areas were comprised of more lowland forest (51%), nonforested wetlands (9%), and streams (3%) than the surrounding NLP. The NLP was comprised primarily of upland forest (44%) and field (32%). Habitat in the northeast and central regions of the NLP was most similar to the habitat composition of bobcat core areas. This model will be useful in aiding Michigan wildlife management agencies with assessing the status and distribution of the NLP bobcat population by identifying areas important to bobcats and supporting the development of regional strategies for carnivore conservation.     

Modeling Wolverine Occurrence Using Aerial Surveys of Tracks in Snow

ABSTRACT We designed a novel approach to determining extent of distribution and area of occupancy for wolverines (Gulo gulo) by using aerial surveys of tracks in snow and hierarchical spatial modeling. In 2005 we used a small, fixed-wing aircraft with pilot and one observer to search 575 of 588 survey units for wolverine tracks in approximately 60,000 km² of boreal forest in northwestern Ontario, Canada. We used sinuous flight paths to scan open areas in the forest in the 100-km² survey units. We detected tracks in 138 (24%) of the 575 sampled units. There was strong evidence of occurrence (probability of occurrence >0.80) in 30% of the 588 survey units, weak evidence of occurrence (0.50–0.80) in 12%, weak evidence of absence (0.20–0.50) in 15%, and strong evidence of absence (< 0.20) in 43%. Wolverine range comprised 59% of the study area and area of occupancy was 33,400 km². With information on probability of occurrence and core areas of occupation for wolverines in our study area, resource managers and others can examine factors that influence wolverine distribution patterns and use this information to formulate best management practices that will maintain wolverines on the landscape in the face of increasing resource development. Comparing future survey results with those of our 2005 survey will provide an objective way to assess the efficacy of management practices.