Habitat characteristics and life history explain reproductive seasonality in lagomorphs

Lagomorphs show extensive seasonal variation in their reproduction. However, the factors causing this large variation have so far mostly been investigated intraspecifically and therefore provide only some exemplary comparisons of lagomorph reproductive seasonality. The present study applies both a categorical description (birth season categories 1–5) and a quantitative measure (birth season length in months) to summarize the degree of birth seasonality in the wild of 69 lagomorph species. Using a comparative approach, I tested the influence of 13 factors, comprising six habitat, five life history and two allometric variables on birth season length in lagomorphs. Leporids mainly show non-seasonal birthing patterns with high intraspecific variation. Their opportunistic breeding strategy with high reproductive output and their large distribution areas across wide latitude and elevation ranges might be the reasons for this finding. Ochotonids reproduce strictly seasonally, likely because they live at northern latitudes, are high-altitude specialists, and occur in limited distribution areas. The most important factors associated with variation in lagomorph birth seasonality are mid-latitude, mean annual temperature and precipitation of a species’ geographical range and life history adaptations including fewer but larger litters in seasonal habitats. Birth seasons become shorter with increasing latitude, colder temperatures, and less precipitation, corresponding to the decreasing length of optimal environmental conditions. Leporid species with shorter breeding seasons force maternal resources into few large litters to maximise reproductive output while circumstances are favourable. Since allometric variables were only weakly associated with reproductive seasonality, life history adaptations and habitat characteristics determine birth seasonality in Lagomorpha.

Influences of long-term changes in land cover on mammal populations: an example from Mexico

Changes in vegetative cover and land use in the southern part of the Isthmus of Tehuantepec in Oaxaca, Mexico, were identified by analysing satellite images from 2001 and 2014. Fluctuations in population density of mammal species during 2001–2016 in response to these changes were analysed. During 2001–2014 the types of land use that increased in area (per year) were prescribed burning (uncontrolled burning caused by humans) by 105.11 ha, seasonal agricultural plots by 58.14 ha, areas without vegetation by 24.54 ha, and human settlements by 4.13 ha. In the same period, savannahs decreased by 103.94 ha, tropical dry forest by 39.5 ha, secondary forests by 14.46 ha, and human-induced grassland by 0.13 ha per year. The loss of these habitats resulted in low population densities of mammals, including the eastern cottontail Sylvilagus floridanus and the Tehuantepec jackrabbit Lepus flavigularis, which is categorized as Endangered on the IUCN Red List. We recommend establishing a communal ecological reserve in the study area to implement appropriate management strategies for grassland communities and develop a programme of semi-captive breeding to conserve L. flavigularis.