Although defining population structure according to discrete habitat patches is convenient for metapopulation theories, taking this approach may overlook structure within populations continuously distributed across landscapes. For example, landscape features within habitat patches direct the movement of organisms and define the density distribution of individuals, which can generate spatial structure and localized dynamics within populations as well as among them. Here, we use the neighborhood concept, which describes population structure relative to the scale of individual movements, to illustrate how localized dynamics within a population of lizards (Sceloporus arenicolus) arise in response to variation in landscape pattern within a continuous habitat patch. Our results emphasize links between individual movements at small scales and the emergence of spatial structure within populations which resembles metapopulation dynamics at larger scales. We conclude that population dynamics viewed in a landscape context must consider the explicit distribution and movement of individuals within continuous habitat as well as among habitat patches.
When subject to anthropogenic hunting risks, wildlife populations may adjust their anti-predator behaviour; however, such plastic response has rarely been assessed. We assessed the response of eight species (African elephant, Maasai giraffe, plains zebra, common wildebeest, Grant's gazelle, impala, Thomson's gazelle and Kirk's dik dik) towards human observers in a landscape with variable anthropogenic hunting pressure. Using logistic regressions, we tested the effect of habitat type, group size, distance to observer and conservation status of the area on the likelihood of animal behavioural adjustments (walking away, fleeing or giving alarm calls). Habitat type did not affect the likelihood of a response towards humans. Dik diks were less likely to respond towards human when they were in larger groups. In contrast, zebras and Thomson's gazelles were marginally significantly more likely to show a response when in larger groups. Responses of all species were significantly or marginally significantly (elephant) lower with increasing distance from observers (an increase by one meter distance changed the response likelihood by 0.01-0.30). Four species (zebra, wildebeest, impala, dik dik) showed a gradual adjustment of responsiveness according to conservation status and were most responsive in non-protected and least responsive in fully protected areas (0.02-0.29 times less responsive in fully vs. multiple-use areas). However, elephants, giraffes and both gazelle species did not significantly adjust their behaviour according to conservation status. This suggests that the behaviour of some species can be used as useful indicator of conservation status of an area whereas the behaviour of other species does not allow discriminating between management types. More generally, our study highlights the importance of assessing and controlling illegal hunting in multiple-use areas and suggests a stronger consideration of human-induced risk effects in the conservation of ungulates. bs_bs_banner Animal Conservation. Print
Colima is the fourth smallest Mexican state, covering only 0.3% of the surface area of Mexico, but due to the remarkable diversity of physiographic and environmental conditions present in Colima it contains a high biological diversity. We generated an up-to-date herpetofaunal checklist for Colima, with a summary of the conservation status of Colima’s amphibians and reptiles. Our checklist contains a total of 153 species of amphibians and reptiles (three introduced). Thirty-nine are amphibians and 114 are reptiles. More than half of Colima’s herpetofauna are Mexican endemics (66.7% of amphibians, 67.5% of reptiles). Less than 25% of the amphibian and reptile species in Colima are in protected categories according to the IUCN Red List and SEMARNAT. The reptiles in the Marine and Revillagigedo Archipelago regions are the most threatened taxa of the Colima herpetofauna. Colima shares > 80% of its herpetofauna with its neighboring states, Jalisco and Michoacán.
Biodiversity elements with narrow niches and restricted distributions (i.e., ‘short range endemics,’ SREs) are particularly vulnerable to climate change. The New Mexico Ridge-nosed Rattlesnake (Crotalus willardi obscurus, CWO), an SRE listed under the U.S. Endangered Species Act within three sky islands of southwestern North America, is constrained at low elevation by drought and at high elevation by wildfire. We combined long-term recapture and molecular data with demographic and niche modeling to gauge its climate-driven status, distribution, and projected longevity. The largest population (Animas) is numerically constricted (N = 151), with few breeding adults (Nb = 24) and an elevated inbreeding coefficient (ΔF = 0.77; 100 years). Mean home range (0.07km2) is significantly smaller compared to other North American rattlesnakes, and movements are within, not among sky islands. Demographic values, when gauged against those displayed by other endangered/Red-Listed reptiles [e.g., Loggerhead Sea Turtle (
Caretta caretta
)], are either comparable or markedly lower. Survival rate differs significantly between genders (female
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