Potential distribution of fall armyworm in Africa and beyond, considering climate change and irrigation patterns

The fall armyworm, Spodoptera frugiperda (FAW), first invaded Africa in 2016 and has since become established in many areas across the continent where it poses a serious threat to food and nutrition security. We re-parameterized the existing CLIMEX model to assess the FAW global invasion threat, emphasizing the risk of transient and permanent population establishment in Africa under current and projected future climates, considering irrigation patterns. FAW can establish itself in almost all countries in eastern and central Africa and a large part of western Africa under the current climate. Climatic barriers, such as heat and dry stresses, may limit the spread of FAW to North and South Africa. Future projections suggest that FAW invasive range will retract from both northern and southern regions towards the equator. However, a large area in eastern and central Africa is projected to have an optimal climate for FAW persistence. These areas will serve as FAW ‘hotspots’ from where it may migrate to the north and south during favorable seasons and then pose an economic threat. Our projections can be used to identify countries at risk for permanent and transient FAW-population establishment and inform timely integrated pest management interventions under present and future climate in Africa.

Detonating the Population Bomb

Chapter 6 documents the fragmentation of what had previously been a consensus regarding global population growth at the end of the 1960s and beginning of the 1970s, resulting in the emergence of two separate factions. The population establishment continued to promote the position of the erstwhile consensus, which held that rapid population growth in developing countries was a barrier to economic development and could be adequately slowed through voluntary family planning programs. The population bombers contended that population growth anywhere in the world posed an immediate existential threat to the natural environment and American national security and needed to be halted through population control measures that demographers had previously rejected as coercive. These two positions went head-to-head at the UN World Population Conference in 1974, where both were rejected by leaders of developing countries.

Potential Distribution of Fall Armyworm in Africa and Beyond, Considering Climate Change and Irrigation Patterns

The fall armyworm, Spodoptera frugiperda (FAW), first invaded Africa in 2016 and has since become established in many areas across the continent where it poses a serious threat to food and nutrition security. We re-parameterized the existing CLIMEX model to assess the FAW global invasion threat, emphasizing the risk of transient and permanent population establishment in Africa under current and predicted future climates, considering irrigation patterns. FAW can establish itself in almost all countries in eastern and central Africa and a large part of western Africa under the current climate. Climatic barriers, such as heat and dry stresses, may limit the spread of FAW to North and South Africa. Future predictions suggest that FAW invasive range will retract from both northern and southern regions towards the equator. However, a large area in eastern and central Africa is predicted to have an optimal climate for FAW persistence. These areas will serve as FAW ‘hotspots’ from where it may migrate to the north and south during winter seasons and then pose an economic threat. Our projections can be used to identify countries at risk for permanent and transient FAW-population establishment and inform timely integrated pest management interventions under present and future climate in Africa.

A multi-year assessment of blacklegged tick (Ixodes scapularis) population establishment and Lyme disease risk areas in Ottawa, Canada, 2017-2019

Canadians face an emerging threat of Lyme disease due to the northward expansion of the tick vector, Ixodes scapularis. We evaluated the degree of I. scapularis population establishment and Borrelia burgdorferi occurrence in the city of Ottawa, Ontario, Canada from 2017–2019 using active surveillance at 28 sites. We used a field indicator tool developed by Clow et al. to determine the risk of I. scapularis establishment for each tick cohort at each site using the results of drag sampling. Based on results obtained with the field indicator tool, we assigned each site an ecological classification describing the pattern of tick colonization over two successive cohorts (cohort 1 was comprised of ticks collected in fall 2017 and spring 2018, and cohort 2 was collected in fall 2018 and spring 2019). Total annual site-specific I. scapularis density ranged from 0 to 16.3 ticks per person-hour. Sites with the highest density were located within the Greenbelt zone, in the suburban/rural areas in the western portion of the city of Ottawa, and along the Ottawa River; the lowest densities occurred at sites in the suburban/urban core. B. burgdorferi infection rates exhibited a similar spatial distribution pattern. Of the 23 sites for which data for two tick cohorts were available, 11 sites were classified as “high-stable”, 4 were classified as “emerging”, 2 were classified as “low-stable”, and 6 were classified as “non-zero”. B. burgdorferi-infected ticks were found at all high-stable sites, and at one emerging site. These findings suggest that high-stable sites pose a risk of Lyme disease exposure to the community as they have reproducing tick populations with consistent levels of B. burgdorferi infection. Continued surveillance for I. scapularis, B. burgdorferi, and range expansion of other tick species and emerging tick-borne pathogens is important to identify areas posing a high risk for human exposure to tick-borne pathogens in the face of ongoing climate change and urban expansion.

Examining the genetic influences of migratory status on island colonisation by naturally and recently established populations of a bird species

Seasonal migration influences long-distance dispersal and population establishment, which are the two important steps for successful island colonisation. Migratory behaviour facilitates the long-distance dispersal of individuals through frequent appearance outside a species’ normal range, while sedentary behaviour may lead to dispersal by post-fledgling flocks whose accidental immigration provide sufficient propagules for population establishment. We assessed the relative contributions of migratory and sedentary populations to island colonisation, by performing population genetics analyses on four recently and naturally established island populations of the Bull-headed Shrike (Lanius bucephlaus). Analyses using 15 microsatellite loci inferred colonisation by flocks of immigrants from possibly sedentary populations for all the islands studied. On one island, we found a correlation between wing length and the genetic probability of assignment to a migratory population, indicating a genetic contribution by migratory immigrants. Yet migratory immigrants to this island were inferred to be only two over eight years of sampling. We imply that sedentary populations were successful island colonists because more immigrants can be provided through their post-fledgling dispersal than through solitary migration. This is the first attempt to examine, using population genetics, influence of migratory behaviour on island colonisation thereby, bridging the gap between population ecology and island biogeography.

Los distritos rurales: un nuevo concepto de desarrollo territorial. Modelos Centro- Periferia en Castilla-La Mancha

The population movement and the decentralization of urban areas and their outskirts are shaping, in the last thirty years, a different process of spatial distribution and the definition of a new population establishment model. Traditionally, displacements were rural-urban and the major reason was the economic one. Nevertheless, recently this process is more complex and triangular: rural-rural displacements and intern urban migrations in which the population moves from small cores (outskirts) to the capital (urban centre). The economic angle is not able anymore to explain most of the displacements: the biggest rural cores are concentrating the migration flows of outskirt areas, shaping, instead of a traditional marshallian industrial district, a social district that we have named Rural District, which becomes a new concept for territorial development.