Environmental drivers of biseasonal anthrax outbreak dynamics in two multihost savanna systems

Environmental factors are common forces driving infectious disease dynamics. We compared interannual and seasonal patterns of anthrax infections in two multihost systems in southern Africa: Etosha National Park, Namibia, and Kruger National Park, South Africa. Using several decades of mortality data from each system, we assessed possible transmission mechanisms behind anthrax dynamics, examining (1) within- and between-species temporal case correlations and (2) associations between anthrax mortalities and environmental factors, specifically rainfall and the Normalized Difference Vegetation Index (NDVI), with empirical dynamic modeling. Anthrax cases in Kruger had wide interannual variation in case numbers, and large outbreaks seemed to follow a roughly decadal cycle. In contrast, outbreaks in Etosha were smaller in magnitude and occurred annually. In Etosha, the host species commonly affected remained consistent over several decades, although plains zebra (Equus quagga) became relatively more dominant. In Kruger, turnover of the main host species occurred after the 1990s, where the previously dominant host species, greater kudu (Tragelaphus strepsiceros), was replaced by impala (Aepyceros melampus). In both parks, anthrax infections showed two seasonal peaks, with each species having only one peak in a year. Zebra, springbok (Antidorcas marsupialis), wildebeest (Connochaetes taurinus), and impala cases peaked in wet seasons, while elephant (Loxodonta africana), kudu, and buffalo (Syncerus caffer) cases peaked in dry seasons. For common host species shared between the two parks, anthrax mortalities peaked in the same season in both systems. Among host species with cases peaking in the same season, anthrax mortalities were mostly synchronized, which implies similar transmission mechanisms or shared sources of exposure. Between seasons, outbreaks in one species may contribute to more cases in another species in the following season. Higher vegetation greenness was associated with more zebra and springbok anthrax mortalities in Etosha but fewer elephant cases in Kruger. These results suggest that host behavioral responses to changing environmental conditions may affect anthrax transmission risk, with differences in transmission mechanisms leading to multihost biseasonal outbreaks. This study reveals the dynamics and potential environmental drivers of anthrax in two savanna systems, providing a better understanding of factors driving biseasonal dynamics and outbreak variation among locations.The National Science Foundation of South Africa.https://onlinelibrary.wiley.com/r/ecmam2023Veterinary Tropical Disease

Patterns of mega-forest fires in east Siberia will become less predictable with climate warming

Very large fires covering tens to hundreds of hectares, termed mega-fires, have become a prominent feature of fire regime in taiga forests worldwide, and in Siberia in particular. Here, we applied an array of machine learning algorithms and statistical methods to estimate the relative importance of various factors in observed patterns of Eastern Siberian fires mapped with satellite data. More specifically, we tested linkages of “hot spot” ignitions with 42 variables representing landscape characteristics, climatic, and anthropogenic factors, such as human population density, locations of settlements and road networks. Analysis of data spanning seventeen years (2001–2017) showed that during low or moderately high fire seasons, models with full set of variables predict locations of fires with a very high probability (AUC = 95%). Sensitivity, or the ratio of correctly predicted fire pixels to the total number of pixels analyzed, declined to 30–40% during warm and dry years of increased fire activity, especially in models driven by anthropogenic variables only. This analysis demonstrates that if warming in Eastern Siberia continues, forest fires will become not only more frequent but also less predictable. We explain this by examining model performance as a function of either temperature or precipitation. This effect from climate makes it nearly impossible to segregate ignition points from locations, which were burnt several hours or even several days earlier. An increase in secondary burnt locations makes it difficult for machine learning algorithms to establish causality links with anthropogenic and other groups of variables

Spatiotemporal Patterns of Desertification Dynamics and Desertification Effects on Ecosystem Services in the Mu Us Desert in China

Degradation of semi-arid and arid ecosystems due to desertification is arguably one of the main obstacles for sustainability in those regions. In recent decades, the Mu Us Desert in China has experienced such ecological degradation making quantification of spatial patterns of desertification in this area an important research topic. We analyzed desertification dynamics for seven periods from 1986 to 2015 and focused on five ecosystem services including soil conservation, water retention, net primary productivity (NPP), crop productivity, and livestock productivity, all assessed for 2015. Furthermore, we examined how ecosystem services relate to each other and are impacted by desertification. Three major conclusions are drawn from the study. First, the eastern part of the study area experienced overall improvement while desertification in the west first increased and then reversed its trend during those periods between 1986 and 2015. Second, significant synergistic relationships are observed for three regulating services (soil conservation, water retention, NPP) and two provisioning services (crop productivity and livestock productivity). Strong relationships across different types of ecosystem services were found only between crop productivity and NPP. Third, in response to increasing desertification, the three regulating services exhibit a monotonically decreasing trend, while the two provisioning services follow a hump-shaped response

Understanding Grassland Degradation and Restoration from the Perspective of Ecosystem Services: A Case Study of the Xilin River Basin in Inner Mongolia, China

Ecosystem services (ESs) and their transformations in northern China play a crucial role in regional sustainability. During the past several decades, grassland degradation has become one of the most important ecological and economic issues in this region. Therefore, understanding the impacts of grassland degradation and restoration on ESs is essential for maintaining ecological resilience and social security of Northern China. Our objective was to explore the relationship between ESs and grassland changes induced by vegetation succession in the Xilin River Basin, Inner Mongolia, China. Using vegetation maps derived from remotely sensed imagery collected in 1983, 1989, 2000, and 2011, we calculated the degree of grassland degradation using the Grassland Degradation Index (GDI). Aboveground biomass (AGB), soil conservation (SC), and water retention (WR) were also estimated to assess ESs for each year. Our results show that: (1) GDI increased during 1983–2000 and decreased during 2000–2011 indicating that after experiencing two decades of severe degradation the grassland has been restored since 2000. (2) AGB and SC were significantly negatively correlated with GDI. Changes in grassland conditions significantly affected WR and SC with both declining during 1983–2000 and increasing afterwards. The increase of SC, however, was slow compared to AGB and WR, which is an indication of time lag in soil restoration. (3) Grasslands in the middle and lower reaches experienced worse degradation than in the upper reaches. (4) AGB and SC exhibited a synergy, while trade-offs existed between AGB and WR and SC and WR. In summary, significant changes in grassland ecosystems in the Xilin River Basin over the past three decades affected the dynamics of ESs among which SC and WR require special attention in the future

Urban vegetation and income segregation in drylands: a synthesis of seven metropolitan regions in the southwestern United States

To better understand how urbanization affects the amount and timing of urban vegetation in drylands we investigated remotely sensed vegetation patterns across seven large metropolitan regions in the southwestern United States. We asked (1) how low density urban land cover differed from adjacent wildland grass, herb, and shrub land covers in both the amount of vegetation and the length of the growing season, (2) how neighborhood income affected patterns of vegetation within low density urban cover, and (3) how cities differed from one another in their vegetation patterns. We found that urbanization generally has a strong influence on vegetation compared to adjacent wildlands. In four of the metropolitan regions the cumulative enhanced vegetation index (EVI) and growing season length in low density developments were higher than grass, herb, and shrub land covers. Within all metropolitan regions, there was a significant socioeconomic effect where higher income areas had a higher cumulative EVI than lower income areas. The large differences in urban vegetation among cities were related to precipitation and total domestic water use. These findings help to identify how urbanization influences vegetation, with implications for the availability of ecosystem services and requirements for irrigation in hot dryland cities

Ecology and sustainability of the Inner Mongolian Grassland: Looking back and moving forward

Context Understanding the ecology and sustainability of the Inner Mongolian Grassland is crucial for improving land management policies in the Mongolian Plateau and beyond. However, a systematic and comprehensive review of the relevant literature is still lacking. Objectives This review was intended to: (1) assess the current state of the ecological and sustainability research of the Inner Mongolian Grassland region, and (2) identify critical research topics and challenges for understanding pathways to sustainability of the region. Methods We conducted a bibliometric analysis of 2571 English articles indexed in the Web of Science during 1998-2019. Multiple methods, including descriptive statistics, principal component analysis, change point detection, theme mining, and association strength analysis, were combined to analyze the sampled literature. Results All reviewed studies can be grouped into four types: description of ecological and biogeochemical characteristics of degraded grasslands (type I), the impacts of climate change and human activities on aboveground (type II) and belowground grassland ecosystem functioning (type III), and the impacts of different management strategies on grassland ecosystem services and human well-being (type IV). The number of publications in all four themes has rapidly increased after 2007-2009. The four types of articles were related to each other in terms of the interannual publication consistency. Keyword co-occurrence network analysis showed that climate change and grazing were the major research topics, which are closely related to all other topics. Conclusions Three perspectives have persisted in the ecology and sustainability research of the Inner Mongolian Grassland: Ecology in the Grassland, Ecology of the Grassland, and Sustainability of the Grassland. Based on the emerging landscape sustainability science framework, the transdisciplinary approach to landscape sustainability diagnostics and landscape planning and design should become a priority in advancing sustainability research of the region

Ecological Civilization: Perspectives from Landscape Ecology and Landscape Sustainability Science : editorial to the special issue

Reversing ecological degradation is critical for survival of many species but will not occur without a transformational reduction in humanity’s environmental impact. Ecological civilization is a way of approaching social and ecological reform and represents a new standard of human existence that may be sustainable well into the future. However, how to achieve ecological civilization still remains a question. Landscape sustainability science, with its theoretical basis in sustainability science and landscape ecology, offers a decisive path for achieving an ecological civilization. Three concepts integral to landscape ecology will be essential for contributing to an ecological civilization: (1) linking landscape patterns with biodiversity and ecosystem processes/function across scales, (2) measuring connectivity and flows across spatially heterogeneous systems, and (3) a systems understanding of the linkages between disturbance, resilience, and recovery. Achieving an ecological civilization is within the scope of human capability, but it will require a fundamental shift in world view and cooperation amongst all actors in the human race. A key place to start is with landscapes. This editorial provides perspectives from landscape ecology and landscape sustainability science for achieving this goa