Biology subjects

Kleijn, D.

Publications and source records attributed to Kleijn, D..

5 recordsLinked to original sources

bioRxiv2025

Assessment of the adverse effects of pollution on farmland bird diversity in contemporary agricultural landscapes

The escalating global demand for food has intensified agricultural practices, leading to substantial changes in land use. This transformation poses a threat to farmland biodiversity, compounded by the presence of pollutants from anthropogenic activities. While the impact of specific pollutants is known in controlled environments, their compounded effects under field conditions remain largely unexplored. We investigated correlations between farmland bird distribution, landscape features, land use patterns, and anthropogenic pressures, including nutrient pollution, acidifying compounds, and synthetic chemicals. Using distribution maps of the Netherlands at a 1x1 km{superscript 2} grid cell, we analyzed the association of farmland bird species richness and abundance with landscape characteristics and varying levels of exposures to unintended pollutants. We also compared species richness distribution patterns between 1998 and 2018. We found a strong negative relationship between farmland bird species richness and abundance with atmospheric deposition of inorganic nitrogen (NHx, NOy). Furthermore, mixed associations were observed between farmland birds and local toxic pressure variation in surface waters, with consistent relationships to industrial chemicals (negative) and products of combustion (positive). Lastly, change in species richness from 1998 and 2018, showed that many of the relationships observed now were already evident two decades ago, with recent declines in species richness concentrated in landscapes hosting a considerable number of species, and low nitrogen deposition grid cells. We conclude that although it is likely that there is some direct negative effects of pollutants on farmland birds, it is reasonable to also assume that the identified relationships are proxies for the overarching intensity of farming, human disturbance, and broader landscape changes. Our study highlights a) a possible role of synthetic pollutants and acidifying eutrophicating substances in farmland bird decline b) the need for well-designed field studies to complement correlative evidence from big data approaches such as ours to enhance our understanding and c) the broader implications for sustainable land management, emphasizing the importance of a holistic approach in addressing the intricate relationships between pollutants and landscape changes.

ecology↗

bioRxiv2021

Additive and synergistic effects of arbuscular mycorrhizal fungi, insect pollination and nutrient availability in a perennial fruit crop

Managing ecosystem services may reduce the dependence of modern agriculture on external inputs and increase the sustainability of agricultural production. Insect pollinators and arbuscular mycorrhizal fungi (AMF) provide vital ecosystem services for crop production, but it has not been tested whether their effects on crop yield interact and how their effects are influenced by nutrient availability. Here we use potted raspberry (Rubus idaeus L.) plants in a full-factorial randomized block design to assess the interacting effects of insect pollination, AMF inoculation and four levels of fertilizer application. AMF inoculation increased the per-plant flower number by 33% and fruit number by 35%, independently from insect pollination and fertilizer application. Single berry weight furthermore increased more strongly with fertilizer application rates in AMF inoculated plants than in non-inoculated plants. As a consequence, AMF inoculation boosted raspberry yield by 43% compared to non-inoculated plants. AMF inoculation increased pollinator visitation rate under intermediate fertilizer levels, suggesting additional indirect effects of AMF on yield. Fruit yield of pollinated plants increased more strongly with fertilizer application rate than the yield of plants from which pollinators had been excluded. At maximum nutrient availability, the combined benefits of both ecosystem services resulted in a 135% higher yield than that of fertilizer-only treatments. Our results suggest that benefits of ecosystem services on yield can be additive or synergistic to the effects of conventional management practices. Intensive, high-input farming systems that do not consider the potential adverse effects of management on ecosystem service providing species may risk becoming limited by delivery of ecosystem services. Pro-actively managing ecosystem services, on the other hand, has the potential to increase crop yield at the same level of external inputs.

ecology↗

bioRxiv2021

rasterdiv - an Information Theory tailored R package for measuring ecosystem heterogeneity from space: to the origin and back

O_LIEcosystem heterogeneity has been widely recognized as a key ecological feature, influencing several ecological functions, since it is strictly related to several ecological functions like diversity patterns and change, metapopulation dynamics, population connectivity, or gene flow. C_LIO_LIIn this paper, we present a new R package - rasterdiv - to calculate heterogeneity indices based on remotely sensed data. We also provide an ecological application at the landscape scale and demonstrate its power in revealing potentially hidden heterogeneity patterns. C_LIO_LIThe rasterdiv package allows calculating multiple indices, robustly rooted in Information Theory, and based on reproducible open source algorithms. C_LI

ecology↗

bioRxiv2021

From zero to infinity: minimum to maximum diversity of the planet by spatio-parametric Rao's quadratic entropy

AimThe majority of work done to gather information on Earth diversity has been carried out by in-situ data, with known issues related to epistemology (e.g., species determination and taxonomy), spatial uncertainty, logistics (time and costs), among others. An alternative way to gather information about spatial ecosystem variability is the use of satellite remote sensing. It works as a powerful tool for attaining rapid and standardized information. Several metrics used to calculate remotely sensed diversity of ecosystems are based on Shannons Information Theory, namely on the differences in relative abundance of pixel reflectances in a certain area. Additional metrics like the Raos quadratic entropy allow the use of spectral distance beside abundance, but they are point descriptors of diversity, namely they can account only for a part of the whole diversity continuum. The aim of this paper is thus to generalize the Raos quadratic entropy by proposing its parameterization for the first time. InnovationThe parametric Raos quadratic entropy, coded in R, i) allows to represent the whole continuum of potential diversity indices in one formula, and ii) starting from the Raos quadratic entropy, allows to explicitly make use of distances among pixel reflectance values, together with relative abundances. Main conclusionsThe proposed unifying measure is an integration between abundance- and distance-based algorithms to map the continuum of diversity given a satellite image at any spatial scale.

ecology↗

bioRxiv2019

A global synthesis reveals biodiversity-mediated benefits for crop production

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by few abundant species or rely on high richness remains unclear. Using a global database from 89 crop systems, we partition the relative importance of abundance and species richness for pollination, biological pest control and final yields in the context of on-going land-use change. Pollinator and enemy richness directly supported ecosystem services independent of abundance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.

ecology↗