| 1. |
- Arnell, Matilda, 1987-
(author)
-
Distribution patterns of fleshy-fruited woody plants at local and regional scales
- 2022
-
Doctoral thesis (other academic/artistic)abstract
- Fleshy-fruited woody plants share a long history with humans, providing us with food and wood material. Because of this relation, we have actively moved some of these plants across landscapes and continents. In Sweden, these species are often found in open and semi-open habitats such as forest edges, their fruits are most often dispersed by birds and their flowers are, with some exceptions, pollinated by insects. In this thesis my overall aim was to map and analyse distribution patterns of fleshy-fruited woody plants in Sweden to expand our knowledge on the mechanisms governing their distributions. First, I mapped a population of the early flowering, fleshy-fruited shrub Daphne mezereum (common mezeron, tibast) and surveyed the reproduction and fruit removal of all individuals (chapter I). My main aim was to investigate to what extent reproduction and fruit removal was affected by local distribution patterns. Secondly, I mapped local distribution patterns of fleshy-fruited woody species and analysed spatial associations between life stages and species (chapter II). My main aim was to relate these spatial associations to predictions of how bird dispersal would shape the local distribution patterns and the hypothesis that birds create ‘wild orchards’. Thirdly, I digitized historical maps and surveyed fleshy-fruited woody species along transects across landscapes (chapter III). My aim was to examine the hypothesis that these species accumulate in open and semi open habitats created by human land use. Fourthly, I estimated range filling of woody plants in Sweden at a 1 km2 resolution (chapter IV). My aim was to compare these estimates among species with different dispersal systems to understand the effect of dispersal on the occupancy of woody species at regional scales.I found the distribution patterns of these species to be affected by past and present land use, supporting the hypothesis that these plants accumulate in open habitats. Occurrences of species in this guild in todays’ forest are positively related to past human land use (chapter III) and the density of D. mezereum increases with decreasing distances to forest edges (chapter I). This accumulation may in part be explained by the positive effect of forest edges on reproduction and fruit removal (chapter I). I further found local distribution patterns of this guild and the individual species to be aggregated (chapter I and II), and spatial associations between saplings and reproductive individuals to support the ‘orchard’ hypothesis (chapter II). The aggregated pattern of fruit-bearing individuals was positively related to fruit removal whereas aggregated flowering individuals was negatively related to fruit set (chapter I). On the regional scale, I found these species to occupy climatically suitable areas, or fill their potential ranges, to a less extent that wind dispersed trees and shrubs (chapter IV), which may indicate dispersal limitation.In conclusion, the behaviour of birds and humans have shaped, and still shape the current distribution of fleshy-fruited trees and shrubs in Sweden, resulting in accumulation in open habitats and locally aggregated distribution patterns. Changing land-use practices and potential mismatches between fruit maturation and bird dispersal with a changing climate may thus result in even lower chances of these species to fill their potential ranges, due to habitat losses and dispersal limitations at local and regional scales.
|
|
| 2. |
- Arnell, Matilda, et al.
(author)
-
Does historical land use affect the regional distribution of fleshy-fruited woody plants?
- 2019
-
In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:12
-
Journal article (peer-reviewed)abstract
- Species richness and composition of current vegetation may reflect historical land use. We develop and examine the hypothesis that regional distribution and richness of fleshy-fruited woody plants, a group sharing life-form and dispersal system, reflect historical land use in open or semi-open habitats. Historical land use was based on maps from around the year 1900 for two regions in Sweden, and field data was gathered from surveys made in these regions. Species richness was positively related to historical land use indicated as open habitat in 1900. In one of the regions, five out of nine examined species were positively related to historical land use (with historical effect R-2 ranging between 0.03 and 0.22). In the other region, we found a weaker positive relationship with historical land use in two out of nine examined species (R-2 0.01 and 0.02). We conclude that current occurrence and richness of fleshy-fruited woody species is partly a legacy of historical land use, and that regions may vary in this respect. Based on a comparison between the two regions examined here, we discuss some potential causes behind this variation.
|
|
| 3. |
- Arnell, Matilda, et al.
(author)
-
Landscape-scale range filling and dispersal limitation of woody plants
- 2022
-
In: Journal of Biogeography. - : Wiley. - 0305-0270 .- 1365-2699. ; 49:11, s. 2028-2036
-
Journal article (peer-reviewed)abstract
- Aim: The extent to which species fill their predicted current ranges and the underlying process of dispersal limitation have implications for species' abilities to track climate change. Range filling is intimately related to spatial scale, yet range filling estimates at high resolutions are largely lacking. In this study, we aim to estimate range filling and dispersal limitation at a high resolution for woody plants with different dispersal systems and habitat affinities.Location: Sweden.Taxon: All genera of woody plants (trees and shrubs).Methods: We estimated landscape-scale range filling for 64 species. Two main dispersal systems, vertebrate dispersal and abiotic dispersal, occurred among these species. Range filling was estimated as the realized range divided by the potential range, that is, the occupied proportion of a species' modelled range, at a 1 km2 resolution. We estimated potential ranges using species distribution models and realized ranges from presence records. To increase the likelihood that absences represented true absences the estimations were restricted to areas with high sampling effort. We tested the effects of dispersal system on range filling, controlling for species' habitat affinities.Results: Vertebrate-dispersed woody species had significantly lower landscape-scale range filling than species with abiotic dispersal. Range filling was also linked to habitat affinity. Species associated with intermediate levels of light and moisture had the highest range filling estimates.Main conclusions: Landscape-scale range filling of woody species is linked to their dispersal traits. When controlling for habitat affinity, our result suggests that dispersal limitation partly explains the lower occupancy in suitable habitat found for vertebrate-dispersed plants. Given that vertebrate-dispersed species fail to reach suitable habitats at this scale, they are less likely to track changes in climate than woody plants with abiotic dispersal.
|
|
| 4. |
- Arnell, Matilda, et al.
(author)
-
Local distribution patterns of fleshy-fruited woody plants - testing the orchard hypothesis
- 2021
-
In: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 44:3, s. 481-492
-
Journal article (peer-reviewed)abstract
- Plant distribution patterns are influenced by many different factors. We examined mechanisms behind local distribution patterns of boreo-nemoral fleshy-fruited woody plants with seed dispersal mainly mediated by birds. It has been suggested that guilds of these plants develop 'orchards', i.e. locally aggregated occurrences composed of several species. We analysed spatially explicit occurrence data of different life stages of a local guild of fleshy-fruited woody plants in south-eastern Sweden, and conducted a seedling recruitment experiment for a subset of ten species. Spatial point pattern analyses showed that the guild of fleshy-fruited species was aggregated at small (< 10 m) spatial scales. Saplings were more common under canopies of heterospecific reproductive individuals than expected by chance. These results show that the local guild of fleshy-fruited species is distributed as orchards, i.e. clusters consisting of individuals of different species and life stages. We found no evidence of negative distance dependence between saplings and reproductive conspecific individuals. Results from the recruitment experiment suggest that recruitment is seed limited and generally low among the studied species. At the site-scale (circular areas with 50 m radius), there was no difference in seedling recruitment between sites with and without reproductive conspecific individuals for most species included in the recruitment experiment. This further suggests that the aggregated patterns found are not simply a result of spatial concordance in suitable habitats across life stages. Instead, we suggest that the sheer number of seeds from species in the guild deposited under the crowns of fruit bearing individuals is the main mechanism behind the build-up of orchards. Although further studies are needed to fully disentangle the processes underlying the observed patterns of local diversity, we argue that describing patterns and contrasting them to the predictions of ecologically relevant hypotheses is a useful first step.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Arnell, Matilda, 1987-, et al.
(author)
-
Reproductive success, fruit removal and local distribution patterns in the early-flowering shrub Daphne mezereum
- 2023
-
In: Nordic Journal of Botany. - 0107-055X .- 1756-1051. ; :10
-
Journal article (peer-reviewed)abstract
- In insect-pollinated, bird-dispersed plants, both investment in reproduction and reproductive success involve interactions between plants and their pollinators and dispersers. The outcome of these plant–animal interactions may be affected by the number of flowers and fruits, as well as by the plants' local environment and by spatial associations among plants. In this study we mapped the spatial distribution of individuals in a population of the early flowering, fleshy-fruited shrub Daphne mezereum, in a forest in boreo-nemoral Sweden. For all mapped individuals we collected data on numbers of flowers and fruits and fruit removal, for three consecutive years. We analysed spatial associations among individuals, and the effects on reproductive performance and fruit removal of plant height, numbers of flowers and fruits, distance to forest edge, and neighbouring flower and fruit density. Our results show that the density of D. mezereum increases with increasing proximity to forest edge. The number of flowers produced, as well as fruit set and fruit removal, show the same positive relationship with increasing proximity to forest edges. We further show that individuals are aggregated up to distances of about 10 m. The flower production of neighbouring conspecific individuals within 10 m is negatively related to fruit set whereas the fruit production of neighbours is positively related to fruit removal. Our main conclusion is that the spatial distribution of D. mezereum affects reproductive success and fruit removal, which in turn has the potential to feed back to the spatial distribution pattern. Combining studies of reproduction with spatial analyses is important to advance our understanding of the dynamics of plant populations.
|
|
| 8. |
- Eriksson, Ove, et al.
(author)
-
Historical Ecology of Scandinavian Infield Systems
- 2021
-
In: Sustainability. - : MDPI. - 2071-1050. ; 13:2
-
Journal article (peer-reviewed)abstract
- Infield systems originated during the early Iron Age and existed until the 19th century, although passing many transitions and changes. The core features of infield systems were enclosed infields with hay-meadows and crop fields, and unenclosed outland mainly used for livestock grazing. We examine the transitions and changes of domesticated landscapes with infield systems using the framework of human niche construction, focusing on reciprocal causation affecting change in both culture and environment. A first major transition occurred during the early Middle Ages, as a combined effect of a growing elite society and an increased availability of iron promoted expansion of villages with partly communal infields. A second major transition occurred during the 18th and 19th centuries, due to a then recognized inefficiency of agricultural production, leading to land reforms. In outlands, there was a continuous expansion of management throughout the whole period. Even though external factors had significant impacts as well, human niche construction affected a range of cultural and environmental features regarding the management and structure of domesticated landscapes with infield systems. Thus, niche construction theory is a useful framework for understanding the historical ecology of infield systems.
|
|
| 9. |
- Eriksson, Ove, et al.
(author)
-
Niche construction, entanglement and landscape domestication in Scandinavian infield systems
- 2017
-
In: Landscape research. - : Informa UK Limited. - 0142-6397 .- 1469-9710. ; 42:1, s. 78-88
-
Journal article (peer-reviewed)abstract
- Domesticated landscapes are formed by complex social and ecological interactions. We study present-day remnants of species-rich hay meadows and pastures in Scandinavia, with historical roots in former infield systems', initially developed during the first centuries AD and maintained until the modernisation of agriculture during the nineteenth and twentieth centuries. Infield systems include infields, enclosed areas near farms incorporating hay meadows and crop fields, and surrounding outlying land used mainly for grazing. We interpret the development of Scandinavian infield systems and their relationship to vegetation and human culture using concepts of niche construction and entanglement. A key issue revolves around spatio-temporal stabilisation of managed grasslands, in turn related to a complex of interactions between cultural development (e.g. perceptions of land ownership and management practices) and ecological patterns (e.g. species richness). We propose that niche construction and entanglement are useful concepts bridging studies in social history and ecology, and for developing conservation programmes in cultural landscapes.
|
|
