A time-frequency analysis on the impact of climate variability on semi-natural mountain meadows

This paper analyses the impact of climate on vegetation growth for a rural, mountainous region in North-Eastern Portugal. In particular, we measure vegetation growth by using the ten-days synthesis dataset (S10) from Satellite Pour l’Observation de la Terre SPOT-VEGETATION imagery from 1998 to 2011. We examine the dynamic patterns of vegetation growth inferred by the normalized difference vegetation index (NDVI).We test whether the growth pattern of the NDVI has changed due to climate variability and we test the relationship of NDVI with temperature and available soil water. In order to check for changes in the growth cycles we use a time-frequency approach based on Kalman filter regressions in the time domain. We find a change of the cyclical pattern for the spring season and different changes if we take into account all seasons. This suggests that individual seasons may undergo cyclical changes which are different to other seasons. Our analysis shows that temperature and available soil water are the main drivers of vegetation growth. We can also recognise a shift of the relative importance away from temperature to soil water

Europe's ecological backbone: recognising the true value of our mountains

Europe's mountain areas have social, economic and environmental capital of significance for the entire continent. This importance has been recognised since the late 19th century through national legislation; since the 1970s through regional structures for cooperation; and since the 1990s through regional legal instruments for the Alps and Carpathians. The European Union (EU) first recognised the specific characteristics of mountain areas in 1975 through the designation of Less Favoured Areas (LFAs). During the last decade, EU cohesion policy and the Treaty of Lisbon have both focused specifically on mountain

Sagebrush landscape: Upper Gunnison River Basin, Colorado Social-Ecological Climate Resilience Project

Prepared with: The Gunnison Climate Working Group and Stakeholders in Gunnison, Colorado for: the North Central Climate Science Center, Ft. Collins, Colorado.April 30, 2017.Includes bibliographical references.Utilizing climate stories to understand the social and ecological impacts to the sagebrush landscape, the team worked with stakeholders to develop three overarching landscape‐scale adaptation strategies. Each of the strategies has a suite of potential actions required to reach a desired future condition. The three key strategies are: 1) identify and protect climate refugia sites (persistent areas), 2) maintain or enhance the resilience of the climate refugia sites, and 3) accept, assist and allow for transformation in non‐climate refugia sites. If adopted by the local community, including land managers and landowners, the framework and strategies resulting from this project can help to reduce the adverse impacts of climate change, allowing for a more sustainable human and natural landscape

Ecological resilience at semi-arid and temperate boundaries of the Mediterranean-type Fynbos Biome, South Africa, during the Holocene

Mediterranean-type ecosystems are amongst the most vulnerable to global change. Threats from desertification are projected due to rapid expansion of adjacent semiarid systems. Changes in fire frequency and intensity can alter ecosystem composition and structure, and potentially facilitate transitions between alternative stable states. Given the outstanding biodiversity of the Mediterranean-type fynbos biome in the Greater Cape Floristic Region (GCFR) of South Africa, understanding of the longterm impacts of global change are particularly important. In this study, palaeoecological data are used to assess the effects of changes in climate, fire and land use on vegetation at the semi-arid and temperate margins of the fynbos biome. Previous palaeoecological studies have shown stable fynbos during the recent geologic past, which restricts interpretation of the long-term ecological processes that determine biome resilience. This study sourced sediment cores directly from presentday fynbos-succulent karoo (semi-arid) and fynbos-afrotemperate forest biome boundaries to emphasise ecological dynamics. Fossil pollen, spores and charcoal were extracted from radiocarbon dated sediment cores to provide proxies for vegetation, hydrology, large herbivore abundance and fire. Constrained hierarchical clustering (CONISS), optimal sequence splitting by least-squares, and Non-metric Multidimensional Scaling (NMDS) was applied to the fossil data to identify distinct assemblages in the record, and to further elucidate ecosystem trajectories through time. At the semi-arid boundary at Groenkloof (5,500 cal yrs BP - near present), decreased moisture and fire from 4,000-735 cal yrs BP allowed colonisation of fynbos by a possible 'no-analogue' community dominated by Asteraceae and Poaceae. From 735 cal yrs BP however, climatic amelioration allowed fynbos to re-establish. The system can therefore be viewed as resilient through a capacity for 'recovery' and persistence through turnover in internal composition of fynbos taxa. This sensitive response to climatic forcing reflects the dominant influence of physiological stress at the semiarid limits of Mediterranean-type ecosystems, as well as a Gleasonian type community composition with loose species associations. In contrast, ecosyste

Guide to the ecological systems of Colorado

Includes bibliographical references