Precipitation variability at inter-and intra-annual scales may influence land-use management decisions in semi-arid savannas worldwide, and in particular, over the Kavango-Zambezi Transfrontier Conservation Area (KAZA) in southern Africa. Over KAZA, spatiotemporal precipitation variability forced by the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) is important to local and regional-scale decisions for planting, livestock grazing, and wildlife migration patterns. We investigate the annual water year (October-September) and early rainy season [October-November-December (OND)] precipitation patterns during 60 years before and after a 1970s shift in the global ocean-atmosphere system for this region in southern Africa.The coincidence of the number of wet (upper tercile) and dry (lower tercile) years and OND seasons during the various phases of ENSO and IOD are compared prior to (1950-1975) and after (1980-2008 the 1970s climate shift over KAZA. Since the 1970s climate shift, KAZA has been significantly drier and observed fewer wet years and OND seasons. ENSO is the dominant forcing of precipitation differences over southern Africa before and after the 1970s climate shift, with IOD playing a secondary role. However, when ENSO and IOD phases are analysed simultaneously, El Niño and positive IOD events are significantly related to dry periods.The forcing of atmospheric circulation over southern Africa before and after the 1970s climate shift during El Niño and La Niña events is significantly different. Prior to the 1970s climate shift, atmospheric circulation during El Niño (La Niña) favoured strong (weak) precipitation increases (decreases). Afterward the 1970s climate shift, atmospheric circulation during La Niña (El Niño) favoured strong (weak) precipitation decreases (increases). The shifting nature of climate modes, especially ENSO, and respective influence on rainfall variability for southern Africa is important to understand to better inform seasonal climate forecasts to improve operational decision-making for land-use and water management decisions in semi-arid savanna regions.
Coral reefs are degrading through the impacts of multiple anthropogenic stressors. How are coral reef communities going to change and how to protect them for future generations are important conservation questions. Using coral reef data from Mauritius, we examined changes in cover in 23 benthic groups for a 13-yr period and at 15 sites. Moreover, we determined which land-based stressor out of four (human population, agriculture, tourism, rainfall) correlated the most with the observed changes in coral reef cover. Among the stony corals, Acropora corals appeared to be the most impacted, decreasing in cover at many sites. However, the non-Acropora encrusting group increased in cover at several sites. The increase in abundance of dead corals and rubble at some sites also supported the observations of stony coral decline during the study period. Additionally, the decline in stony corals appeared to be more pronounced in second half of the study period for all sites suggesting that a global factor rather than a local factor was responsible for this decline. There was little change in cover for the other benthic groups, some of which were quite rare. Human population was significantly correlated with changes in coral reef cover for 11 sites, followed by tourism and agriculture. Rainfall, a proxy for runoff, did not appear to affect coral reef cover. Overall, our results showed that there has been a decline of stony coral cover especially the ones with complex morphologies, which in turn suggest that coral reefs around Mauritius have experienced a decline in habitat complexity during the study period. Our study also suggests that humans are an important factor contributing to the demise of coral reefs around the island.
Elephants have a major influence on vegetation structure, composition and ecosystem processes, and are primary agents of habitat change in Africa. At moderate-to-high population densities, elephants can damage vegetation, especially when enclosed in protected areas. This study examines the effects of elephant browsing on woody trees in Majete Wildlife Reserve (WR), south-western Malawi. Regression analysis is used to assess the associations of six factors known to drive elephant browsing in other areas and determine which ones have the most influence on browsing at Majete WR. Twenty-four per cent of tagged trees had been subject to elephant browsing. The model with vegetation type, stem diameter and distance from permanent water correctly predicted browsing for 80% of the observations. Elephants mostly favoured riparian woodlands, followed by Acacia-dominated woodland and Brachystegia-dominated woodland. Browsing occurrence was negatively related to distance from permanent water and diameter at breast height(DBH). A larger number of trees, sampled at random and covering a larger portion of the reserve would provide more reliable estimates of browsing and related factors. Knowledge of time-and sitespecific factors affecting elephant browsing can be used to forecast future habitat transformations and manipulate the range of the elephants within the reserve. R esum eLes el ephants ont une influence majeure sur la structure et la composition de la v eg etation et sur les processus ecosyst emiques, et ce sont des acteurs primordiaux des changements d'habitats en Afrique. Lorsque leur densit e de population est de mod er ee a elev ee, les el ephants peuvent endommager la v eg etation, surtout s'ils sont enferm es a l'int erieur d'une aire prot eg ee. Cette etude examine les effets des el ephants qui consomment des arbres ligneux dans la R eserve de Faune (RF) de Majete, au sud-ouest du Malawi. Nous utilisons une analyse de r egression pour evaluer les associations de six el ements connus pour influer sur l'alimentation des el ephants en d'autres endroits, et pour d eterminer lesquels influencent le plus la consommation des el ephants a la RF de Majete. Vingt-quatre pourcents des arbres marqu es ont et e touch es par des el ephants. Le mod ele comprenant le type de v eg etation, le diam etre des troncs et la distance par rapport a un point d'eau permanent a permis de pr edire correctement 80 % des cas de consommation par les el ephants. Les el ephants privil egiaient surtout les forêts riveraines, suivies des forêts domin ees par l'Acacia et par celles domin ees par Brachystegia. Les cas de consommation etaient n egativement li es a la distance par rapport a un point d'eau permanent et a la dbh. Un grand nombre d'arbres, choisis au hasard et couvrant une grande partie de la r eserve, permettraient d'obtenir des estimations plus fiables de la consommation des el ephants et des facteurs qui y sont li es. Ce que l'on sait des facteurs sp ecifiques du temps et du site affectant la consommation des el ephants peut servir a p...
Forests in the United States are managed by multiple public and private entities making harmonization of available data and subsequent mapping of management challenging. We mapped four important types of forest management, production, ecological, passive, and preservation, at 250-meter spatial resolution in the Southeastern (SEUS) and Pacific Northwest (PNW) USA. Both ecologically and socio-economically dynamic regions, the SEUS and PNW forests represent, respectively, 22.0% and 10.4% of forests in the coterminous US. We built a random forest classifier using seasonal time-series analysis of 16 years of MODIS 16-day composite Enhanced Vegetation Index, and ancillary data containing forest ownership, roads, US Forest Service wilderness and forestry areas, proportion conifer and proportion riparian. The map accuracies for SEUS are 89% (10-fold cross-validation) and 67% (external validation) and PNW are 91% and 70% respectively with the same validation. The now publicly available forest management maps, probability surfaces for each management class and uncertainty layer for each region can be viewed and analysed in commercial and open-source GIS and remote sensing software.
Haiti’s agrarian society is highly sensitive to changes in weather and climate conditions. Little is known about Haitian farmers’ perceptions of climate-related risks and their ability to cope with hazards, which may reduce the relevance and likelihood of success of proposed adaptation solutions. We discuss the findings from the focus groups held with 104 small-holder farmers from mountain areas. Farmers in the study area regard the impacts of climate hazards on their livelihood as significant but largely prioritize short-term solutions over long-term protective measures, which potentially increase their vulnerability over time. The study provides insights on local decision processes and potential pathways for discussing climate information with farmers. It identifies the types of information perceived as necessary for informed decision-making. The findings, while in some cases distinctive to the study area, have implications for the design of climate change adaptation interventions in other contexts.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.