The influence of matrix type on flower visitors of Centaurea jacea L.

Hirsch, Michaela; Pfaff, S.; Wolters, Volkmar

doi:10.1016/s0167-8809(03)00093-8

Cited by 25 publications

(11 citation statements)

References 22 publications

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“…S4). The Wnding that the quality of the matrix can be a key factor determining the response of plants and animals to habitat fragmentation was conWrmed by other studies (Hirsch et al 2003;Williams et al 2006).…”

Section: Discussionmentioning

confidence: 77%

Delayed response in a plant–pollinator system to experimental grassland fragmentation

Rusterholz

Baur

2010

Oecologia

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The fragmentation of natural habitat is considered to be a major threat to biodiversity. Decreasing habitat quality and quantity caused by fragmentation may lead to a disruption of plant-pollinator interactions and to a reduction in sexual reproduction in plant species. We conducted a 6-year field experiment to investigate the effects of small-scale fragmentation on plant-pollinator interactions and genetic diversity in the self-compatible Betonica officinalis. We examined the abundance and composition of pollinators, the foraging behaviour of bumblebees and the performance, outcrossing rate and genetic diversity of B. officinalis after 2 and 6 years in experimentally fragmented nutrient-poor, calcareous grassland in the northern Swiss Jura mountains. Fragments of different size (2.25 and 20.25 m(2)) were isolated by a 5-m-wide strip of frequently mown vegetation. Control plots of corresponding size were situated in adjacent undisturbed grassland. Experimental grassland fragmentation altered the composition of B. officinalis pollinators and reduced their flower visitation rate. Furthermore, the foraging behaviour of bumblebees was changed in the fragments. After 6 years of fragmentation seed weight was higher in fragments than in control plots. However, the densities of B. officinalis rosettes and inflorescences, plant height and inflorescence length were not affected by fragmentation. The outcrossing frequency of B. officinalis growing in fragments was reduced by 15% after 2 years and by 33% after 6 years of experimental fragmentation. This resulted in a significant reduction of the genetic diversity in seedlings emerging in fragments after 6 years. Our study shows that small-scale habitat fragmentation can disturb the interaction between B. officinalis and pollinators resulting in a reduced outcrossing frequency and genetic diversity in plants growing in fragments. However, the response to fragmentation was considerably delayed. This finding strengthens the claim for long-term field experiments with proper replications and controls to assess delayed effects of habitat fragmentation.

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Section: Discussionmentioning

confidence: 77%

Delayed response in a plant–pollinator system to experimental grassland fragmentation

Rusterholz

Baur

2010

Oecologia

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“…ants, beetles, birds), as well as for plants, e.g. by Dauber et al (2003), Waldhardt and Otte (2003), Steiner and Köhler (2003) and Hirsch et al (2003). A precondition for such an assessment is to allocate a certain value to each land use and habitat type.…”

Section: Biodiversity Indicators At Landscape Level With Reference Tomentioning

confidence: 99%

Biodiversity and agri-environmental indicators—general scopes and skills with special reference to the habitat level

Büchs¹

2003

Agriculture, Ecosystems & Environment

132

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This synoptic review has the intention to summarise and highlight results in respect to the area "biodiversity and habitat" considering the current "state of the art" with regard the development of biotic indicator approaches that refer to the fauna of agro-ecosystems.Most political statements (e.g. "Convention of Biodiversity Development": Agenda 21, Convention of Rio 1992) as well as existing approaches regarding the development of biotic agri-environmental indicators focus mainly and almost exclusively on "biodiversity", the enhancement of which is the overall target for the development of agricultural landscapes towards sustainability. In this regard the understanding of the term "biodiversity" is rather different: it is largely interpreted as species richness, only occasionally as the richness of varieties, cultivars or genetical expressions (e.g. microorganisms).A survey on the understanding of biotic indicators is presented including aspects of nomenclature, categorisation and definitions as well as preconditions and rules for their use. Requirements for different taxa (mostly invertebrates) to act as biotic indicators are summarised and several attempts to use animals on the population and/or community level as biotic indicators for biodiversity or other goals in agro-ecosystems are discussed critically as well as their replacement by surrogate indicators. Regarding the sensitivity of indicators it will be highlighted that it is necessary to evaluate and to compare cultivation intensities, that are rather similar (e.g. gradual differences in conventional managed farms and landscapes) as well as those displaying much larger differences (e.g. organic farming versus conventional farming), because conventional farms currently cover nearly 90% of the agriculturally used area in Europe. Other fundamental problems regarding the development of biotic indicators as baselines, sample size, frequency of surveys, mutual neutralisation of indicators, double assessments, selection of taxa, etc. are addressed. Finally an assessment of the practicality, the power of indication statements and the remaining work required to validate indicators will be provided for discussion, as well as suggestions for a simplification of indicator systems in order to minimise the input needed for data recording.

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“…The class of the matrix is important for many invertebrate communities in cities as the conditions are influenced by the length of the ecotones, the quality of the surrounding matrix, and the 'quality' of the patch (Aizen and Feinsinger 1994;Webb 1989;Âs 1999;Duelli et al 1999;Golden and Crist 1999;Ricketts 2001;Hirsch et al 2003). Quality of the patch, as determined by species-specific preferences, can refer to the increased area and diversity of foliage type and height (including grass cover), canopy cover, and the presence of woody debris and hollows (Hodgkison et al 2007).…”

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confidence: 99%

The importance of urban backgardens on plant and invertebrate recruitment: a field microcosm experiment

Sperling

Lortie

2009

Urban Ecosyst

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Private backgardens in cities have the capacity to enhance ecological function and connectivity. The importance of increased habitat availability was tested experimentally using microcosms with soil or with soil and vegetation added into Toronto backgardens. Local attributes of the backgardens were recorded, and within the microcosms, recruitment of seeds, plants, and winged and wingless invertebrates were recorded. Natural recruitment by all organisms was significant into the microcosms in the 20 backgardens tested. Invertebrate abundance and diversity, incidental seed recruitment, and aboveground vegetation growth was enhanced regardless of whether only bare soil was added or soil with vegetation. The number of woody plants (non-herbaceous plants with hard lignified tissues or woody parts e.g., stems and are adapted to survive from one year to the next i.e., through winter) in the backgardens predicted seed recruitment and number of plant species predicted winged invertebrate abundance. Hence, simple augmentation of private backgardens-even at an ecologically small-scale-can enhance the capacity of urban systems to provide appropriate habitats for organisms within a difficult matrix for many species.

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The influence of matrix type on flower visitors of Centaurea jacea L.

Cited by 25 publications

References 22 publications

Delayed response in a plant–pollinator system to experimental grassland fragmentation

Delayed response in a plant–pollinator system to experimental grassland fragmentation

Biodiversity and agri-environmental indicators—general scopes and skills with special reference to the habitat level

The importance of urban backgardens on plant and invertebrate recruitment: a field microcosm experiment

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