Zach J. Farris

Predator–Primate Distribution, Activity, and Co-occurrence in Relation to Habitat and Human Activity Across Fragmented and Contiguous Forests in Northeastern Madagascar

Predator–primate interactions are understudied, yet predators have been shown to influence primate behavior, population dynamics, and spatial distribution. An understanding of these interactions is important for the successful management and conservation of these species. Novel approaches are needed to understand better the spatial relationships between predators and primates across changing landscapes. We combined photographic surveys of predators and humans with line-transect sampling of lemurs across contiguous and fragmented forests in Madagascar to 1) compare relative activity; 2) estimate probability of occupancy and detection; 3) estimate predator–primate and local people–primate co-occurrence; and 4) assess variables influencing these parameters across contiguous and fragmented forests. In fragmented (compared to contiguous) forest sites endemic predator and lemur activity were lower whereas introduced predator and local people activity were higher. Our two-species interaction occupancy models revealed a higher number of interactions among species across contiguous forest where predator and lemur occupancy were highest. Mouse lemurs show evidence of “avoidance” (SIF < 1.0) with all predator species (endemic and introduced) in contiguous forest whereas white-fronted brown lemurs show “attraction” (SIF > 1.0) with feral cats and local people in contiguous forest. Feral cats demonstrated the highest number of interactions with lemurs, despite their distribution being limited to only contiguous forest. Distance to forest edge and distance to nearby villages were important in predicting predator occupancy and detection. These results highlight the growing threat to endemic predators and lemurs as habitat loss and fragmentation increase throughout Madagascar. We demonstrate the effectiveness of a novel combination of techniques to investigate how predator species impact primate species across a gradient of forest fragmentation.

Hunting, Exotic Carnivores, and Habitat Loss: Anthropogenic Effects on a Native Carnivore Community, Madagascar

The wide-ranging, cumulative, negative effects of anthropogenic disturbance, including habitat degradation, exotic species, and hunting, on native wildlife has been well documented across a range of habitats worldwide with carnivores potentially being the most vulnerable due to their more extinction prone characteristics. Investigating the effects of anthropogenic pressures on sympatric carnivores is needed to improve our ability to develop targeted, effective management plans for carnivore conservation worldwide. Utilizing photographic, line-transect, and habitat sampling, as well as landscape analyses and village-based bushmeat hunting surveys, we provide the first investigation of how multiple forms of habitat degradation (fragmentation, exotic carnivores, human encroachment, and hunting) affect carnivore occupancy across Madagascar’s largest protected area: the Masoala-Makira landscape. We found that as degradation increased, native carnivore occupancy and encounter rates decreased while exotic carnivore occupancy and encounter rates increased. Feral cats (Felis species) and domestic dogs (Canis familiaris) had higher occupancy than half of the native carnivore species across Madagascar’s largest protected landscape. Bird and small mammal encounter rates were negatively associated with exotic carnivore occupancy, but positively associated with the occupancy of four native carnivore species. Spotted fanaloka (Fossa fossana) occupancy was constrained by the presence of exotic feral cats and exotic small Indian civet (Viverricula indica). Hunting was intense across the four study sites where hunting was studied, with the highest rates for the small Indian civet (x¯ = 90 individuals consumed/year), the ring-tailed vontsira (Galidia elegans) (x¯ = 58 consumed/year), and the fosa (Cryptoprocta ferox) (x¯ = 31 consumed/year). Our modeling results suggest hunters target intact forest where carnivore occupancy, abundance, and species richness, are highest. These various anthropogenic pressures and their effects on carnivore populations, especially increases in exotic carnivores and hunting, have wide-ranging, global implications and demand effective management plans to target the influx of exotic carnivores and unsustainable hunting that is affecting carnivore populations across Madagascar and worldwide.

Feral cats and the fitoaty : first population assessment of the black forest cat in Madagascar’s rainforests

Despite exceptionally high levels of biodiversity and endemism found in Madagascar, much of its wildlife remains little studied, particularly the carnivore community. The recently described, little-known black forest cat (locally known as “fitoaty”) is believed to be restricted to NE Madagascar and has been investigated only through village surveys and anecdotal accounts. From 2008 to 2012, we photographically sampled 7 forest sites with varying degrees of degradation and fragmentation across Makira Natural Park with the goals of: 1) estimating landscape occupancy for fitoaty (Felis spp.), 2) identifying variables influencing fitoaty occupancy, and 3) comparing fitoaty and feral cat (Felis spp.) occupancy across the landscape. We observed higher occupancy for fitoaty, minimal co-occurrence between fitoaty and feral cats (n = 2 sites), and strong divergence in habitat use. We provide the 1st assessment of fitoaty morphology, including comparisons with anecdotal reports, and the 1st population assessment of Madagascars exotic cat community with insights into factors associated with carnivore population trends in Madagascar. We suggest the described fitoaty is a phenotypically different form of the feral cat, but additional research is needed. Targeted management plans are needed to diminish the spread and potential negative effects of invasive cats across this important biologically diverse ecoregion.

Estimating Encounter Rates and Densities of Three Lemur Species in Northeastern Madagascar

Primate populations, including Madagascar’s lemurs, are threatened worldwide and conservationists need accurate population estimates to develop targeted conservation plans. We sought to fill knowledge gaps for three lemur taxa —white-fronted brown lemur (Eulemur albifrons); eastern woolly lemur (Avahi laniger); and Allocebus/Microcebus, a category combining observations of hairy-eared dwarf lemurs (Allocebus trichotis) and mouse lemurs (Microcebus spp.)— in northeastern Madagascar by estimating their density, examining how their encounter rates and densities vary across three different forest types, and monitoring trends in encounter rates and densities at resurveyed sites, using data from surveys at six forest sites over a 4-year period (2010–2013). Landscape density for white-fronted brown lemur, eastern woolly lemur, and Allocebus/Microcebus was 21.5 (SE 3.67), 57.7 (SE 9.17), and 39.1 (SE 9.55) individuals/km2, respectively. There was no difference in density estimates at intact and intermediately degraded forest sites; however, we encountered white-fronted brown lemurs more often in intact forest (1.64 ± SE 0.40 individuals/km) than in intermediately degraded and degraded forest (0.15 ± SE 0.06 and 0.16 ± SE 0.06 individuals/km). In addition, we encountered white-fronted brown lemurs at lower rates in 2013 (0.15 ± SE 0.06 individuals/km) compared to 2010 (0.82 ± SE 0.12 individuals/km) at a resurveyed site. Our findings emphasize that primate researchers must account for variation in how lemur encounter rates and densities differ between intact and degraded forests, and although we observed a decline in white-fronted brown lemur encounter rate at our resurveyed site, we caution that changes in lemur encounter rates may simply reflect lower detection rates rather than lower density. Future research should focus on using conventional distance sampling techniques, which are infrequently used in primate studies, to provide more robust density estimates as a way to accurately assess trends and the effects of anthropogenic pressures on lemur populations.

Using camera traps to examine distribution and occupancy trends of ground-dwelling rainforest birds in north-eastern Madagascar

Camera trap surveys are a non-invasive way to monitor wildlife populations. Although most often used to study medium- and large-sized mammals, camera traps also detect non-target species. These detections provide useful ecological information on little-known species, but such data usually remain unanalysed. We used detections from camera-trapping surveys of native carnivores and small mammals to examine distribution patterns and occupancy trends of little-known ground-dwelling rainforest birds at seven sites across the Masoala-Makira protected area complex in north-eastern Madagascar. We obtained 4,083 detections of 28 bird species over 18,056 trap nights from 200 to 2013. We estimated occupancy across the Masoala-Makira protected area complex (hereafter, landscape occupancy) and annual trends in occupancy at three resurveyed sites for five commonly observed species. Landscape occupancy across Masoala-Makira ranged from 0.75 (SE 0.09; Madagascar Magpie-robin Copsychus albospecularis ) to 0.25 (SE 0.06; Scaly Ground-roller Geobiastes squamiger ). Ground-dwelling forest bird occupancy was similar at forest sites that ranged from intact to fully degraded; however, three species were detected less often at sites with high feral cat trap success. Nearly half of all focal species showed declines in annual occupancy probability at one resurveyed site (S02) from 2008 to 2013. The declines in ground-dwelling bird occupancy could have community-wide consequences as birds provide ecosystem services such as seed dispersal and pest regulation. We suggest immediate conservation measures—such as feral cat removal—be implemented to protect ground-dwelling forest birds and other threatened taxa across this landscape.

Landscape trends in small mammal occupancy in the Makira–Masoala protected areas, northeastern Madagascar

Madagascars native small mammals (Tenrecidae and Nesomyinae) are understudied. To help fill these knowledge gaps, we analyzed 1,575 detections of small mammals obtained during camera-trap surveys at 7 sites in northeastern Madagascar (2008–2011) using single-season occupancy analyses in program PRESENCE. We estimated landscape occupancy and detection probabilities of tufted-tailed rats (Eliurus spp.), red forest rats (Nesomys spp.), greater hedgehog tenrecs (Setifer setosus), and common tenrecs (Tenrec ecaudatus) and examined how these parameters responded to habitat characteristics, habitat degradation, and the trap success of native and exotic carnivorans. Only Nesomys showed a marked difference in mean occupancy between intact (Ψ = 0.71 ± SE 0.06), intermediately degraded (Ψ = 0.23 ± SE 0.05), and degraded (Ψ = 0.34 ± SE 0.06) forest sites. Only Nesomys and Setifer occupancy was strongly influenced by habitat characteristics; Nesomys occupancy was positively related to distance away from forest edge (β = 1.39 ± SE 0.27) and percent rainforest cover (β = 1.89 ± SE 0.39), and Setifer occupancy negatively related to average canopy height (β = –0.52 ± SE 0.25). We found trap success of exotic carnivorans had little influence on small mammal occupancy and detection probabilities (with the exception of Eliurus). We suggest that camera traps are a valid method for studying aspects of small mammal ecology, but caution researchers to consider characteristics of camera traps (e.g., trigger speed) to increase potential inference.