Curtice R. Griffin

Mapping Landscape Resistance to Identify Corridors and Barriers for Elephant Movement in Southern Africa

One of Africas greatest conservation successes is the recovery of elephant (Loxodonta africana) populations within protected areas (e.g. Aleper and Moe 2006), such as those in northern Botswana. This recovery poses several challenges, however. First, habitat within protected areas is becoming degraded from high intensity elephant browsing. Second, the increasing elephant and human populations in the region have led to large increases in human—elephant conflict along the periphery of protected areas (Sitati et al. 2005; Lee and Graham 2006). Management options include facilitating natural dispersal, active relocation, and culling. Relocation is prohibitively expensive as a population-level solution given the high per capita cost. Culling is politically unpopular given Botswanas booming wildlife tourist industry. Simultaneously, large areas of the neighboring countries of Namibia, Zambia and Angola have low elephant densities. Some of these governments desire to increase elephant populations within their protected areas to promote the growth of wildlife tourism. Thus, facilitated dispersal of elephants from high density areas of northern Botswana to protected areas in other countries with low elephant densities is an attractive potential solution.

Continent-wide survey reveals massive decline in African savannah elephants

African elephants (Loxodonta africana) are imperiled by poaching and habitat loss. Despite global attention to the plight of elephants, their population sizes and trends are uncertain or unknown over much of Africa. To conserve this iconic species, conservationists need timely, accurate data on elephant populations. Here, we report the results of the Great Elephant Census (GEC), the first continent-wide, standardized survey of African savannah elephants. We also provide the first quantitative model of elephant population trends across Africa. We estimated a population of 352,271 savannah elephants on study sites in 18 countries, representing approximately 93% of all savannah elephants in those countries. Elephant populations in survey areas with historical data decreased by an estimated 144,000 from 2007 to 2014, and populations are currently shrinking by 8% per year continent-wide, primarily due to poaching. Though 84% of elephants occurred in protected areas, many protected areas had carcass ratios that indicated high levels of elephant mortality. Results of the GEC show the necessity of action to end the African elephants’ downward trajectory by preventing poaching and protecting habitat.

Productivity of early successional shrubland birds in clearcuts and groupcuts in an eastern deciduous forest

Uneven-aged forest management has been advocated as a silvicultural practice because of concerns about the negative effects of even-aged management on birds that dwell in mature forests. Recent evidence, however, indicates that in the northeastern United States, bird species that inhabit early successional habitats may be experiencing more widespread declines than their mature-forest counterparts. We compared the effect of group selection, a widely used form of uneven-aged forest management, and clearcutting on nest survival rates of early successional shrubland birds in the White Mountains of New Hampshire. There was no difference in daily nest survival rate between clearcuts (0.990) and groupcuts (0.987) for 16 bird species combined (n = 290), and no difference in daily nest survival rate between clearcuts (0.993) and groupcuts (0.987) for chestnut-sided warblers (Dendroica pensylvanica), the only species for which enough nests were found for separate analysis (n = 217). There was no difference in daily nest survival rates of all species combined between edge (0.983) and interior areas (0.992) of clearcuts (n = 204), and no difference in daily nest survival rates of chestnut-sided warblers between edge (0.984) and interior (0.993) areas of groupcuts (n = 156). Thus, our results suggest that clearcuts and groupcuts provide similar habitat for species of early successional shrubland birds that inhabit both clearcuts and groupcuts. Recent studies, however, indicate that some bird species that use larger openings such as clearcuts do not occupy smaller openings created by group selection, which may limit the utility of group selection in managing habitat for early successional shrubland birds.

Wetland use by river otters in Massachusetts

Wetland loss and vegetational change in the northeastern United States could affect river otter (Lutra canadensis) populations, but few studies have addressed river otter use of wetlands in this region. We documented wetland types used by river otters during 1988-89 in central Massachusetts by using latrine revisitation rates as an index to habitat use. We determined whether use varied by season or wetland type by comparing revisitation rates of river otters at 86-134 otter latrines located in different wetland types. We also characterized shoreline habitats at latrines by comparing habitat features at 132 river otter latrines with nearby, unused shoreline sites, using uni- and multivariate techniques

Nest predator distribution among clearcut forest, forest edge and forest interior in an extensively forested landscape

Abstract The distribution of avian and mammalian nest predator species in clearcut forest, forest edge and forest interior habitats was assessed on four study plots in 1992 and 1993 using line transect counts. Red squirrels (Tamiasciurus hudsonicus) and eastern chipmunks (Tamias striatus) were detected more often than expected by chance in mature forest than clearcut forest (P 0.05) and was not significantly correlated with conifer basal area or distance from clearcut borders (P>0.05). We conclude that the distribution of two important nest predator species, the eastern chipmunk and the red squirrel, are primarily influenced by the distribution of conifers. However, the distribution of eastern chipmunks and red squirrels are affected by clearcut borders as well.

Recovery strategies for piping plovers in managed coastal landscapes

Abstract Piping plovers (Charadrius melodus) that nest and winter along the U.S. Atlantic coast are threatened by cumulative impacts of habitat loss and alteration, human disturbance, and predation. Coastal stabilization activities may degrade plover habitat by altering natural processes of dune and beach erosion and accretion. Dredging and beach nourishment projects may be beneficial or detrimental to plovers, depending on timing and location. Management strategies to reduce disturbance and mortality caused by beachgoers and off‐road vehicles include fencing of nesting and brood‐rearing areas, partial or complete beach closures to pedestrians or vehicles during the breeding season, restrictions on pets, and public education. Beaches where piping plovers nest are owned and managed by a variety of federal and state agencies, county and municipal governments, private conservation organizations, and individuals. The roles of these and other landowners and managers in plover recovery efforts are discussed. Wi...

FEEDING BEHAVIOR AND FOOD HABITS OF WINTERING HARLEQUIN DUCKS AT SHEMYA ISLAND, ALASKA

Abstract The foraging ecology of wintering Harlequin Ducks (Histrionicus histrionicus) is poorly understood and information on basic food habits is lacking for this species in the Aleutian Islands of Alaska where the largest winter concentrations occur. We investigated feeding behavior and food habits of wintering Harlequin Ducks in the western Aleutian Islands of Alaska with respect to sex and temporal and environmental variables to document behavioral responses to winter conditions, resource use, and nutritional requirements. We found that on average, Harlequin Ducks spent most of the diurnal period feeding (70% males, 76% females). However, more time was spent feeding during evenings, midwinter, cold weather, and high tides. Gastropods, crustaceans, and diptera larvae made up 83% of the diet, but diet composition changed throughout winter. Despite change in food habits, diet energy density was stable throughout winter.

A Phylogenetic Approach to Reversed Size Dimorphism in Diurnal Raptors

Several adaptive hypotheses have been proposed to account for reversed size dimorphism (females larger than males) in diurnal raptors, but not consensus has emerged. We adopted a phylogenetic approach by mapping size ratios onto Sibley et al.s phylogeny for the Ciconiisformes, a diverse order that includes diurnal raptors. Reversed size dimorphism (RSD) has apparently evolved at least five times in the Ciconiiformes : four times among aerial-pursuit predators (the diurnal rapors, skuas, boobies, and frigatebirds), and once in a largely polyandrous group that includes the jacanas and phalaropes

Protecting vernal pools: a model from Massachusetts, USA

Ephemeral ponded wetlands, often referred to as vernal pools in the wetland’s lexicon of the northeastern United States, are in need of protection from outright loss, catastrophic alteration, and disruption of natural processes in the surrounding landscape, because of their great importance to a characteristic wildlife fauna. The state of Massachusetts, USA provides a useful model for vernal pool protection. Vernal pools have been specifically protected under state wetlands regulations since 1987 and many of the state’s municipalities have added additional, more stringent protection under local wetland bylaws. Some vernal pools are also protected under federal wetlands protection law. The protection of vernal pools in Massachusetts is based on a certification process in which biological data are collected to demonstrate that a wetland provides vernal pool functions. Once certified, and if a pool meets jurisdictional requirements, regulatory restrictions are placed on development and other activities proposed within the pool. The regulatory protection for vernal pools in Massachusetts has resulted in the prevention of outright loss and degradation of many vernal pools across the state. However, a 2001 US Supreme Court decision, referred to as the SWANCC decision, may result in a loss of federal jurisdiction over many vernal pools, protection that is especially valuable for pools that do not meet state regulatory criteria. Of significant importance is a lack of protection in existing regulations of the upland non-breeding habitat surrounding vernal pools, which has been shown to be of critical importance to the animals that rely on the pools. Despite the shortcomings of the regulatory protection model in Massachusetts, it has been especially effective as a catalyst for environmental and wildlife awareness, public participation in the wetlands regulatory process, and as an extremely valuable tool in environmental education and outreach.

Breeding Ecology and Behavior of the Hawaiian Hawk

We studied the ecology of the endangered Hawaiian Hawk (Buteo solitarius) on the island of Hawaii for three breeding seasons. Their breeding strategy is a prime example of a K-selected species characteristic of many birds in tropical environments: clutch size was one and brood-rearing was among the longest reported for any diurnal raptor. Twenty-eight nests were found in a variety of native and exotic habitats. Incubation lasted 38 days, nestlings fledged after 59-63 days, and parents cared for fledglings for an average of 30.2 weeks, which was 2.5 to 10 times longer than similar-size temperate zone raptors. Males assisted females with incubation, but only females brooded young. Radio-tagged juveniles remained within 0.63 km of their nests for the first two months after fledging, after which dispersal distances expanded gradually. Avian (45%) and mammalian (54%) prey dominated the diet of nestlings. There was no evidence that avian malaria, introduced predators, or environmental contaminants were affecting their population. Based upon estimates of population size, the availability of suitable nesting habitat, and reproductive success, we suggest the species be considered for downlisting from endangered to threatened status.