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Lee and Bond (2018) quantified ecological effects associated with the establishment of the Randelin Wildlife Management Area (WMA) in the Tarangire Ecosystem. Brehony et al.’s (2018) criticisms of Lee and Bond (2018) largely stem from problematic interpretations of what we attempted and reported. Here, we respond to Brehony et al.’s 3 criticisms. First, we clarify that our concept of ecological success followed the specific terminology used in Brooks et al. (2012), thus ecological success of a WMA was defined as improved outcomes for wildlife. Second, we explain that our methods were appropriate and our findings were accurate at our scale of inference. Third, because quantitative anthropocentric analyses are lacking, the “reality” of community-based conservation in WMAs is not known.

Examination of spatial variation in demography among or within populations of the same species is a topic of growing interest in ecology. We examined whether spatial variation in demography of a tropical megaherbivore followed the “temporal paradigm” or the “adult survival paradigm” of ungulate population dynamics formulated from temperate-zone studies. We quantified spatial variation in demographic rates for giraffes (Giraffa camelopardalis) at regional and continental scales. Regionally, we used photographic capture-mark-recapture data from 860 adult females and 449 calves to estimate adult female survival, calf survival, and reproduction at 5 sites in the Tarangire ecosystem of Tanzania. We examined potential mechanisms for spatial variation in regional demographic rates. At the continental scale, we synthesized demographic estimates from published studies across the range of the species. We created matrix population models for all sites at both scales and used prospective and retrospective analyses to determine which vital rate was most important to variation in population growth rate. Spatial variability of demographic parameters at the continental scale was in agreement with the temporal paradigm of low variability in adult survival and more highly variable reproduction and calf survival. In contrast, at the regional scale, adult female survival had higher spatial variation, in agreement with the adult survival paradigm. At both scales, variation in adult female survival made the greatest contribution to variation in local population growth rates. Our work documented contrasting patterns of spatial variation in demographic rates of giraffes at 2 spatial scales, but at both scales, we found the same vital rate was most important. We also found anthropogenic impacts on adult females are the most likely mechanism of regional population trajectories.

Giraffes Giraffa camelopardalis are megafaunal browsers and keystone species in African savanna ecosystems. Range-wide population declines are suspected, but robust data are lacking. Tanzania holds the largest population of giraffe of any range state, and aerial surveys constitute most of Tanzania’s giraffe population monitoring data, but their accuracy has not yet been assessed. An IUCN status assessment for giraffe is currently underway, and calibrating aerial surveys with ground-based surveys can quantify accuracy of the aerial surveys to ensure more reliable estimates of populations nationwide. We estimated giraffe density and abundance in the Tarangire Ecosystem in northern Tanzania using 2 ground survey methods, distance sampling and capture-mark-recapture, and compared our ground-based estimates with those from the most recent aerial survey in 4 sites. We found aerial survey estimates were biased low, while ground-based surveys were more precise and cost less. We computed correction factors to improve the accuracy of aerial surveys and suggested ways to further improve aerial survey methods.

Understanding interactions among site occupancy, reproduction, vegetation, and disturbance for threatened species can improve conservation measures, because important aspects of vegetation and disturbances may be identified and managed. We used 9 yr of survey data collected at 168 sites to investigate dynamic site occupancy and reproduction in a declining population of California Spotted Owls (Strix occidentalis occidentalis) in southern California, USA. We used multistate models to examine the relationship among owl site occupancy, reproduction, high-severity wildland fire, and postfire logging, while accounting for variation in vegetation characteristics and variation in detectability. Both occupancy and reproduction were positively correlated with successful reproduction in the previous year. Tree cover (ha) in a site's 203-ha core area also was positively correlated with both occupancy and reproduction. We detected no effect of disturbance covariates on reproduction, given that a site was occ...

High-severity forest fire often is presumed to adversely affect the occupancy of territories by California Spotted Owls (Strix occidentalis occidentalis) because these owls are associated with mature and old-growth forests. We used single-season, multi-state occupancy statistics to estimate site occupancy probability for Spotted Owls at 45 historically occupied sites during the breeding season immediately following the 2013 Rim Fire, which was one of the largest forest fires on record in California. We quantified how occupancy probability was influenced by the amount of high-severity fire occurring in mature forested habitat within Protected Activity Centers (PACs). The model-averaged estimate of site-occupancy probability for at least a single owl was 0.922 (±SE = 0.073), which was higher than other published occupancy probability estimates for this subspecies in either burned or long-unburned sites in the Sierra Nevada. Mean site-occupancy probability for pairs was 0.866 (±0.093), and most site...

The Black-backed Woodpecker (Picoides arcticus) is a species of conservation concern that is strongly associated with recently burned forests. Black-backed Woodpeckers are known to have variable home-range sizes, yet the ecological factors related to this variation have not been adequately explored and may hold insights into the natural history of the species and the management of its habitat. During 2011 and 2012, we radio-tracked Black-backed Woodpeckers nesting in 3 forested areas of California that burned between 2 and 5 years before the initiation of tracking. Among 15 individuals with robust tracking data, we found that home-range size varied by an order of magnitude, from 24.1 to 304.1 ha, as measured by movement-based kernel estimation. Using an information-theoretic approach, we evaluated the functional relationship between snag basal area—an a priori key resource—and home-range size, additionally controlling for sex, age, and years since fire as covariates. We found that snag basal area...

To maximize fitness, female mammals attempt to maximize offspring survival, whereas males attempt to mate with as many females as possible, which results in differential use of space. The relative influence of male competition versus access to females on space use by males has not been addressed theoretically or empirically. We conducted an experiment in which we manipulated total density, density of females, and density of males to determine relative influence of density of each sex on space use and overlap by male gray-tailed voles (Microtus canicaudus). Home-range size was correlated inversely with total density and was influenced separately by each sex. Home-range sizes of males were significantly smaller in high male-low female populations than in low female-high male populations. Males overlapped 4-5 females and 4-5 other males in populations with low densities of both sexes and high densities of both sexes. When sex ratios were skewed toward females, males still overlapped 4-5 females but only one other male. When sex ratios were skewed toward males, males overlapped only two females while overlapping three other males. Home-range size of a male does not appear to expand beyond an overlap with about five members of either sex. Thus, intrasexual competition with five males or overlap with five females appear to set upper limits to home-range size of male gray-tailed voles. We conclude that space use by males is influenced by intrasexual competition and access to females with an upper limit of overlap with either sex.