Land-use components, abundance of predatory arthropods, and vegetation height affect predation rates in grasslands

One of the major land use and land cover changes in Europe is agricultural land abandonment (ALA) that particularly affects marginal mountain areas. Accurate mapping of ALA patterns and timing is important for understanding its determinants and the environmental and socio-economic consequences. In highly fragmented agricultural landscapes with small-scale farming, subtle land use changes following ALA can be detected with high resolution remotely sensed data, and successional vegetation height is a possible indicator of ALA timing. The main aim of this study was to determine the relationship between successional vegetation height and the timing of agricultural land abandonment in the Budzów community in the Polish Carpathians. Areas of vegetation succession were vectorized on 1977, 1997, and 2009 orthophotomaps, enabling the distinguishing of vegetation encroaching on abandoned fields before and after 1997. Vegetation height in 2012–2014 was determined from digital surface and terrain models that were derived from airborne laser scanning data. The median heights of successional vegetation that started development before and after 1997 were different (6.9 m and 3.2 m, respectively). No significant correlations between successional vegetation height and elevation, slope, aspect, and proximity to forest were found. Thus, the timing of agricultural land abandonment is the most important factor influencing vegetation height, whereas environmental characteristics on this scale of investigation may be neglected.

Download Full-text

High matrix vegetation decreases mean seed dispersal distance but increases long wind dispersal probability connecting local plant populations in agricultural landscapes

10.21203/rs.3.rs-278304/v1 ◽

2021 ◽

Author(s):

Sissi Donna Lozada Gobilard ◽

Florian Jeltsch ◽

Jinlei Zhu

Keyword(s):

Land Use ◽

Seed Dispersal ◽

Dispersal Distance ◽

Population Connectivity ◽

Agricultural Landscapes ◽

Long Distance Dispersal ◽

Long Distance ◽

Vegetation Height ◽

Positive Effect ◽

Seed Dispersal Distance

Abstract Background Seed dispersal plays an important role in population dynamics in agricultural ecosystems, but the effects of surrounding vegetation height on seed dispersal and population connectivity on the landscape scale have rarely been studied. Understanding the effects of surrounding vegetation height on seed dispersal will provide important information for land use management in agricultural landscapes to prevent the spread of undesired weeds or enhance functional connectivity. Methods We used two model species, Phragmites australis and Typha latifolia, growing in small natural ponds known as kettle holes, in an agricultural landscape to evaluate the effects of surrounding vegetation height on wind dispersal and population connectivity between kettle holes. Seed dispersal distance and the probability of long-distance dispersal (LDD) were simulated with the mechanistic WALD model under three scenarios of “low”, “dynamic” and “high” surrounding vegetation height. Connectivity between the origin and target kettle holes was quantified with a connectivity index adapted from Hanski and Thomas (1994). Results Our results show that mean seed dispersal distance decreases with the height of surrounding matrix vegetation, but the probability of long-distance dispersal (LDD) increases with vegetation height. This indicates an important vegetation-based trade-off between mean dispersal distance and LDD, which has an impact on connectivity. Conclusions Matrix vegetation height has a negative effect on mean seed dispersal distance but a positive effect on the probability of LDD. This positive effect and its impact on connectivity provide novel insights into landscape level (meta-)population and community dynamics — a change in matrix vegetation height by land use or climatic changes could strongly affect the spread and connectivity of wind-dispersed plants. The opposite effect of vegetation height on mean seed dispersal distance and the probability of LDD should therefore be considered in management and analyses of future land use and climate change effects.

Download Full-text

Does Habitat Fragmentation Influence Nest Predation in the Shortgrass Prairie?

The Condor ◽

10.1093/condor/103.3.530 ◽

2001 ◽

Vol 103 (3) ◽

pp. 530-536 ◽

Cited By ~ 4

Author(s):

Melissa N. Howard ◽

Susan K. Skagen ◽

Patricia L. Kennedy

Keyword(s):

Habitat Fragmentation ◽

Vegetation Structure ◽

Nest Predation ◽

Patch Size ◽

Mortality Rates ◽

Artificial Nests ◽

Vegetation Height ◽

Native Grassland ◽

Shortgrass Prairie ◽

Predation Rates

Abstract We examined the effects of habitat fragmentation and vegetation structure of shortgrass prairie and Conservation Reserve Program (CRP) lands on predation rates of artificial and natural nests in northeastern Colorado. The CRP provides federal payments to landowners to take highly erodible cropland out of agricultural production. In our study area, CRP lands have been reseeded primarily with non-native grasses, and this vegetation is taller than native shortgrass prairie. We measured three indices of habitat fragmentation (patch size, degree of matrix fragmentation, and distance from edge), none of which influenced mortality rates of artificial or natural nests. Vegetation structure did influence predation rates of artificial nests; daily mortality decreased significantly with increasing vegetation height. Vegetation structure did not influence predation rates of natural nests. CRP lands and shortgrass sites did not differ with respect to mortality rates of artificial nests. Our study area is only moderately fragmented; 62% of the study area is occupied by native grassland. We conclude that the extent of habitat fragmentation in our study area does not result in increased predation in remaining patches of shortgrass prairie habitat. ¿La Fragmentación de Hábitat Influencia la Depredación de Nidos en Praderas de Pasto Corto? Resumen. Examinamos los efectos de fragmentación de hábitat y estructura de la vegetación sobre la tasa de depredación de nidos artificiales y naturales en praderas de pasto corto y tierras del Programa de Reserva de Conservación (CRP) en el noreste de Colorado. El CRP proporciona pagos federales para que los dueños de las tierras retiren sus cultivos de áreas agrícolas altamente erosionables. En nuestra área de estudio, las tierras de CRP han sido vueltas a sembrar principalmente con céspedes no nativos que son más altos que la vegetación nativa de las praderas de pasto corto. Medimos tres índices de fragmentación de hábitat (tamaño del parche, grado de fragmentación de la matriz, y distancia al borde), ninguno de los cuales influyó sobre la tasa de mortalidad de nidos artificiales o naturales. La estructura de la vegetación influenció la tasa de depredación de nidos artificiales: la mortalidad diaria disminuyó significativamente con incrementos en la altura de la vegetación. La estructura de la vegetación no influenció la tasa de depredación de nidos naturales. Los sitios de CRP y de pastos cortos no difirieron con respecto a la tasa de mortalidad de nidos artificiales. Nuestra área de estudio es sólo moderadamente fragmentada pues el 62% del área es ocupada por prado nativo. Concluimos que el grado de fragmentación de hábitat en nuestra área del estudio no causa aumentos en la depredación en los parches de hábitat remanentes.

Download Full-text

Complex Undisturbed Riparian Zones Are Resistant to Colonisation by Invasive Alien Plant Species

Water ◽

10.3390/w12020345 ◽

2020 ◽

Vol 12 (2) ◽

pp. 345 ◽

Cited By ~ 1

Author(s):

Igor Zelnik ◽

Valentina Mavrič Klenovšek ◽

Alenka Gaberščik

Keyword(s):

Land Use ◽

Plant Species ◽

Riparian Zone ◽

Human Impacts ◽

Riparian Zones ◽

Alien Plant Species ◽

Alien Plant ◽

Invasive Alien Plant ◽

Vegetation Height ◽

Herbaceous Perennials

We investigated the presence and abundance of invasive alien plant species (IAS) in the riparian zones of rivers in relation to different environmental parameters. We surveyed the spatial and human-influenced characteristics of the riparian zones, river channels, and land use along seven Slovenian rivers. We further monitored the presence and abundance of IAS with different natural properties and different human impacts to define the characteristics of non-infected and heavily infected reaches. Special attention was given to different life forms of IAS. The presence and abundance of IAS positively correlated with distance from river source, current velocity, and water depth, and negatively correlated with altitude, naturalness of the land use, width and completeness of the riparian zone, height and structure of its vegetation, and condition of the riverbed and banks. Annuals prevailed among IAS at 48%, with 37% herbaceous perennials and 15% woody species. The vine Echinocystis lobata was the most abundant IAS, which was found in 179 out of the 414 river reaches analysed, followed by the annual Impatiens glandulifera and the herbaceous perennial Solidago gigantea. E. lobata was spread over the native riparian vegetation and was affected by the natural gradients of the rivers in terms of altitude and distance from the river’s source. Reaches without IAS significantly differed from reaches colonised with IAS in the width of riparian zone, vegetation height and structure, land-use next to the river, and distance from the source. As IAS in riparian zones affect riparian and aquatic communities, there is the need for management practices to maintain and establish complex riparian zones that are resistant to IAS colonisation.

Download Full-text

Deer Exclusion Changes Vegetation Structure and Hunting Guilds of Spiders, but Not Multitrophic Understory Biodiversity

Diversity ◽

10.3390/d13010025 ◽

2021 ◽

Vol 13 (1) ◽

pp. 25

Author(s):

Roman Bucher ◽

Jonas Rochlitz ◽

Nathalie Wegner ◽

Anna Heiß ◽

Alexander Grebe ◽

...

Keyword(s):

Plant Communities ◽

Vegetation Structure ◽

Structural Changes ◽

Forest Ecosystems ◽

Trophic Levels ◽

Cascading Effects ◽

Vegetation Height ◽

Spider Communities ◽

The Impact ◽

Predatory Arthropods

Ungulate herbivores modify plant community compositions, which can modulate biodiversity at higher trophic levels. However, these cascading effects on herbivorous and predatory arthropods in forest ecosystems remain poorly understood. We compared plant and arthropod communities between fenced exclosures and unfenced control plots in a permanent forest in Germany. After five years of deer exclusion, we quantified plant diversity and vegetation structure as well as the diversity of insects and spiders in 32 pair-wise plots. In addition, we compared spider communities with respect to different hunting guilds because they are expected to have different requirements for vegetation structure. Although we did not find differences in plant communities, vegetation height and heterogeneity were higher in exclosures compared to control plots. The diversity of insects and spiders was not affected by deer presence. However, the abundance of sheet-web weavers and ambush hunters was lower in exclosures whereas ground hunters were more common in exclosure plots. Structural changes in the vegetation changed predator hunting guilds even though mere abundance and biodiversity indices were not affected. We therefore suggest that monitoring of vegetation structure and associated functional groups seems more sensitive to assess the impact of ungulate herbivores compared to taxonomic metrics.

Download Full-text

Using a landscape ecological perspective to analyze regime shifts in social–ecological systems: a case study on grassland degradation of the Tibetan Plateau

Landscape Ecology ◽

10.1007/s10980-021-01191-0 ◽

2021 ◽

Author(s):

Li Li ◽

Fabian Ewald Fassnacht ◽

Matthias Bürgi

Keyword(s):

Land Use ◽

Landscape Ecology ◽

Regime Shift ◽

Soil Formation ◽

Black Soil ◽

Regime Shifts ◽

The Tibetan Plateau ◽

Plateau Pika ◽

Vegetation Height ◽

Social Ecological

Abstract Context Landscape ecology thinking and social–ecological system (SES) thinking investigate human–environment relationships from the perspective of ‘space’ and ‘system’, respectively. To date, empirical landscape ecology studies attempting to understand SES complexities are rare. Objectives Using the Tibetan pastoral landscape as an empirical example, we conceptualize the black-soil formation as SES regime shifts. We seek to illustrate the spatial patterns of black-soil formation in the Tibetan SES, and to reveal their underlying ecological processes. Methods We conducted interdisciplinary research in a Tibetan pastoral village. We obtained quantitative data on historical land-use intensity (LUI) and the associated management narratives. Landsat-based NDVI time series were used to derive a grassland productivity proxy and to reconstruct the process leading to the up-scaling of the regime shift of degradation. Results Important SES features, such as LUI, productivity and degradation risk are heterogeneously distributed in space. Land-use intensification at farm-scales in the 1990s increased landscape-scale degradation risks. Eventually the regime shift of degradation scaled up from the plot level to the landscape level in the 2010s. The time lag was related to the gradual invasion of a native burrowing animal, the plateau pika, which inhabits low-vegetation height pastures. Conclusions Our study shows that landscape ecology thinking provides an important spatial perspective to understanding SES complexities. The finding that unfavorable SES regime shifts are strongly linked across spatial scales implies that an ‘entry point’ into an adaptive management circle should be initiated when local-scale regime shifts are perceived and interpreted as early warning signals.

Download Full-text

Recovery of Soil Hydraulic Properties for Assisted Passive and Active Restoration: Assessing Historical Land Use and Forest Structure

Water ◽

10.3390/w11010086 ◽

2019 ◽

Vol 11 (1) ◽

pp. 86 ◽

Cited By ~ 6

Author(s):

Sergio Esteban Lozano-Baez ◽

Miguel Cooper ◽

Silvio Frosini de Barros Ferraz ◽

Ricardo Ribeiro Rodrigues ◽

Mirko Castellini ◽

...

Keyword(s):

Land Use ◽

Forest Restoration ◽

Hydraulic Properties ◽

Tree Planting ◽

Land Use History ◽

Vegetation Height ◽

Old Growth Forest ◽

Land Use Types ◽

Historical Land Use ◽

Soil Hydraulic

Tree planting and natural regeneration are the main approaches to achieve global forest restoration targets, affecting multiple hydrological processes, such as infiltration of rainfall. Our understanding of the effect of land use history and vegetation on the recovery of water infiltration and soil attributes in both restoration strategies is limited. Therefore, we investigated the recovery of top-soil saturated soil hydraulic conductivity (Ks), soil physical and hydraulic properties in five land use types: (i) a secondary old-growth forest; (ii) a forest established through assisted passive restoration 11 years ago; (iii) an actively restored forest, with a more intensive land use history and 11 years of age; (iv) a pasture with low-intensity use; and (v) a pasture with high-intensity use, in the Brazilian Atlantic Forest. For these land use types, we determined the historical land use patterns and conducted soil sampling, using the Beerkan method to determine Ks values in the field. We also measured tree basal area, canopy cover, vegetation height, tree density and species richness in forest covers. The Ks decreased when land use was more intense prior to forest restoration actions. Our results indicate that land use legacy is a crucial factor to explain the current difference in soil and vegetation attributes among study sites.

Download Full-text

Assessing climate and land-use change impacts on streamflow in a mountainous catchment

Journal of Water and Climate Change ◽

10.2166/wcc.2018.234 ◽

2018 ◽

Vol 11 (2) ◽

pp. 503-513 ◽

Cited By ~ 1

Author(s):

Qiang Liu ◽

Liqiao Liang ◽

Yanpeng Cai ◽

Xuan Wang ◽

Chunhui Li

Keyword(s):

Land Use ◽

Land Use Change ◽

Field Capacity ◽

Soil Parameters ◽

Area Index ◽

Mountainous Catchment ◽

Vegetation Height ◽

Streamflow Response ◽

Model Efficiency ◽

Surrounding Areas

AbstractIt is essential to assess streamflow response to climate and land-use change in catchment basins that serve cities and their surrounding areas. This study used the Distributed Hydrology Soil Vegetation Model (DHSVM) to simulate streamflow under different climate and land-use change scenarios in the Dashi River catchment, China. The most sensitive soil parameters were maximum infiltration, porosity, field capacity, and wilting point, while the most sensitive vegetation parameters were leaf area index (LAI) and vegetation height. The suitability of the DHSVM model was aligned with Nash–Sutcliffe model efficiency coefficients (NSE) greater than 0.41 and 0.84 at daily and monthly scales, respectively. Streamflow increased/decreased with increasing/decreasing precipitation, while it decreased with increasing air temperature. Furthermore, streamflow decreased with the increase in forestland due to higher water consumption, especially during summer. Results from this study could help us to better understand streamflow response to changes in climate and land use.

Download Full-text