Density and activity patterns of bobcat in its southernmost distribution

Estimating density and activity patterns is useful for management and conservation of species. Data for Mexican bobcat (Lynx rufus) populations are scarce. Here we estimated the density of a bobcat population in Oaxaca, southern Mexico, and evaluated its daily activity patterns. We also evaluated macroecological patterns of bobcat density across its distribution range to determine any geographical (latitudinal, longitudinal, elevation, or range centroid) or climatic effects on the population density. Camera–trap data were divided into four 60–day periods (two in the dry season and two in the rainy season). Density was calculated using the random encounter model and daily activity patterns were analyzed fitting a kernel density function. The mean estimated density for the four periods was 17.3 bobcats/100 km2, with the highest densities occurring during the dry periods. Bobcat daily activity pattern presented two peaks, one after midnight and the other after dawn, with very slight changes between seasons. In the study area, density and activity patterns were associated with anthropogenic perturbation and prey availability. Bobcats increased their population density in the dry season, and showed a preference for activity at night and early morning hours when it is cooler and there are likely fewer competitors but more prey. Across its range, bobcat density was mainly related to annual precipitation and mean temperature of the driest quarter at 100 km radius buffers, and between annual precipitation and longitude on a smaller scale (50 km radius buffers). These findings support their preference for the arid or mesic environments that enabled them to reach southern areas of the Neartic region.

Occurrence of mesocarnivores in montane sky islands: How spatial and temporal overlap informs rabies management in a regional hotspot

Interspecific interactions among mesocarnivores can influence community dynamics and resource partitioning. Insights into these interactions can enhance understanding of local ecological processes that have impacts on pathogen transmission, such as the rabies lyssavirus. Host species ecology can provide an important baseline for disease management strategies especially in biologically diverse ecosystems and heterogeneous landscapes. We used a mesocarnivore guild native to the southwestern United States, a regional rabies hotspot, that are prone to rabies outbreaks as our study system. Gray foxes (Urocyon cinereoargenteus), striped skunks (Mephitis mephitis), bobcats (Lynx rufus), and coyotes (Canis latrans) share large portions of their geographic ranges and can compete for resources, occupy similar niches, and influence population dynamics of each other. We deployed 80 cameras across two mountain ranges in Arizona, stratified by vegetation type. We used two-stage modeling to gain insight into species occurrence and co-occurrence patterns. There was strong evidence for the effects of elevation, season, and temperature impacting detection probability of all four species, with understory height and canopy cover also influencing gray foxes and skunks. For all four mesocarnivores, a second stage multi-species co-occurrence model better explained patterns of detection than the single-species occurrence model. These four species are influencing the space use of each other and are likely competing for resources seasonally. We did not observe spatial partitioning between these competitors, likely due to an abundance of cover and food resources in the biologically diverse system we studied. From our results we can draw inferences on community dynamics to inform rabies management in a regional hotspot. Understanding environmental factors in disease hotspots can provide useful information to develop more reliable early-warning systems for viral outbreaks. We recommend that disease management focus on delivering oral vaccine baits onto the landscape when natural food resources are less abundant, specifically during the two drier seasons in Arizona (pre-monsoon spring and autumn) to maximize intake by all mesocarnivores.

Phylogenomic systematics of the spotted skunks (Carnivora, Mephitidae, Spilogale): Additional species diversity and Pleistocene climate change as a major driver of diversification

Four species of spotted skunks (Carnivora, Mephitidae, Spilogale) are currently recognized: Spilogale angustifrons, S. gracilis, S. putorius, and S. pygmaea. Understanding species boundaries within this group is critical for effective conservation given that regional populations or subspecies (e.g., S. p. interrupta) have experienced significant population declines. Further, there may be currently unrecognized diversity within this genus as some taxa (e.g., S. angustifrons) and geographic regions (e.g., Central America) never have been assessed using DNA sequence data. We analyzed species limits and diversification patterns in spotted skunks using multilocus nuclear (ultraconserved elements) and mitochondrial (whole mitogenomes and single gene analysis) data sets from broad geographic sampling representing all currently recognized species and subspecies. We found a high degree of genetic divergence among Spilogale that reflects seven distinct species and eight unique mitochondrial lineages. Initial divergence between S. pygmaea and all other Spilogale occurred in the Early Pliocene (∼ 5.0 million years ago). Subsequent diversification of the remaining Spilogale into an "eastern" and a "western" lineage occurred during the Early Pleistocene (∼1.5 million years ago). These two lineages experienced temporally coincident patterns of diversification at ∼0.66 and ∼0.35 million years ago into two and ultimately three distinct evolutionary units, respectively. Diversification was confined almost entirely within the Pleistocene during a timeframe characterized by alternating glacial-interglacial cycles, with the origin of this diversity occurring in northeastern Mexico and the southwestern United States of America. Mitochondrial-nuclear discordance was recovered across three lineages in geographic regions consistent with secondary contact, including a distinct mitochondrial lineage confined to the Sonoran Desert. Our results have direct consequences for conservation of threatened populations, or species, as well as for our understanding of the evolution of delayed implantation in this enigmatic group of small carnivores.

Comparison between terrestrial mammals in evergreen forests and in seasonal dry forests in Western Ecuador: should efforts be focused on dry forests?

The Coast Region of Ecuador has been dramatically deforested, and most of the remaining natural vegetation is formed of fragmented patches, in which there is little knowledge of wild mammal populations. The objective of this study was to assess the presence and detection rate (DR) of medium and large-size mammals by using camera-traps in fragmented forests located outside the protected areas comparing the two main types of forest: seasonal dry and evergreen. We registered 18 different species, of which four had greater DRs in dry forests (Lycalopex sechurae, Odocoileus peruvianus, Simosciurus stramineus and Sylvilagus daulensis), four were more detected in evergreen forests (Cuniculus paca, Dasyprocta punctata, Dasypus novemcinctus and Procyon cancrivorus), and the remaining 10 species had no significant habitat preference. The mean species richness was similar in both ecosystems, but the number of detections was greater in the evergreen forests. Finally, two of the region’s four threatened species had higher DRs in dry forests. These results suggest that it is necessary to conserve both types of ecosystems to ensure the conservation of all mammals’ species. However, since dry forests are less protected and their threatened fauna suggests that conservation efforts should be particularly focused on them.