Orchards And The Biodiversity Action Plan
Traditional orchards and their associated habitats, such as grasslands, walls, ponds and hedges, support a wide variety of wildlife. However, there have been relatively few systematic studies of the biodiversity value of traditional orchards. To help to fill this gap, English Nature set up a project in 2004 to review of the extent, distribution, biodiversity and management of traditional orchards in England. The study objectives included reviewing existing information on the extent, distribution, biodiversity, management and current conservation status of traditional orchards and surveying a number of representative orchards to assess their biodiversity interest.
The aim of the surveys was to illustrate the kind of wildlife that orchards which are managed in a low intensity way can support, with particular reference to lichens, fungi, bryophytes (mosses and liverworts) and invertebrates. Habitat survey and collection of management information provided the context for the detailed survey of the chosen taxa. Resource constraints meant that only a small number of sites (six) could be surveyed. Thus the results should be seen as indicative case studies rather than exhaustive comparisons of different types of orchards or rigorous analysis of variation in response to geographical position, which would require more study sites to be surveyed.
The habitat surveys of each orchard included recording a sample of orchard trees for girth size and veteran tree features, assessing the species composition of the orchard floor vegetation and the orchard boundaries and noting the presence of associated features such as ponds. Epiphytic lichen and bryophyte species and their abundances were recorded, and, for bryophytes only, all species found on a sample set of individual trees. Fungus species were recorded in spring and autumn from orchard trees, fallen dead wood, the orchard floor and boundary features.
Invertebrate species were recorded during 4 visits to each orchard, by manual searching, suction sampling, sweeping, beating, window flight interception traps and water traps. The main groups covered included Coleoptera, Heteroptera, Aculeate Hymenoptera, Psocoptera, Orthoptera and some Diptera. Broadway Farm Orchards were an exception in that the fruit tree census and invertebrate survey were carried out in 2003, with slightly different methods. Contextual information was gathered from a variety of different data sets including ancient woodland inventories, First Edition Ordnance Survey maps and 2003 aerial photographs. Historical and management information was supplied by orchard owners and managers.
The results were evaluated with reference to assemblages and communities represented and rarity and conservation status of habitats and species, including presence of BAP priority habitats and species and threatened species listed in Red Data Books. In addition, Indicators of Ecological Continuity were identified in the lichen and invertebrate data sets, using published lists of these Indicators.
The overall numbers of species found in the species surveys were: 131 epiphytic lichens, 50 epiphytic bryophytes, 175 fungi and 454 invertebrate species. The sites varied in their diversity for different groups, for example Slew Orchard was the richest for lichens, and Rummers Lane Orchards had the most bryophytes. The sites also had a wide range of communities and associations, for example lichen communities ranged from a community (the Usneion) on very well-lit trees in humid conditions to a deeply shaded bark community (the Pyrenulatum). Numbers of species represented in assemblages varied across sites, for example saproxylic (wood decay) invertebrate faunas were particularly rich in Broadway Farm Orchards, Slew Orchard and Park Farm Orchard, while the highest number of ground layer invertebrate species were found in Park Farm Orchard. Fungi associated with dead wood were particularly varied at Broadway Farm Orchards, Rummers Lane Orchards and Park Farm Orchard. The character of the lichen and invertebrate groups had particular similarities to wood pasture and parkland flora and fauna.
Key conclusions from the results of the orchard surveys are:
a) Orchards are hotspots for biodiversity in the countryside, supporting a wide range of wildlife and containing BAP priority habitats and species as well as an array of nationally rare and scarce species. The wildlife of orchard sites depends on the mosaic of habitats they encompass, including fruit trees, scrub, hedgerows, hedgerow trees, non-fruit trees within the orchard, the orchard floor habitats, fallen dead wood and associated features such as ponds and streams.
b) Different orchards have particular biodiversity value for different groups, for example waxcap grassland may be a feature in one orchard, epiphytic lichens in another and saproxylic invertebrates in a third site. Therefore conservation of orchards as series of sites is required to conserve the full range of biodiversity they support.
c) Orchards, like wood pastures, are dynamic habitats and the habitat they provide for groups such as saproxylic invertebrates will change with the demography of orchard trees in a particular site. Continuity of habitat requires trees at all stages of growth, either within one orchard or a set of orchards in a landscape.
d) Orchards appear to be a significant part of a spatial series or network of habitats at a landscape scale, which are able sustain scarce lichens and beetles, and perhaps other taxa, that require continuity of habitat through time. This network is made up of orchards, hedgerow trees, wood pasture and ancient woodland, all of which are within Biodiversity Action Plans apart from orchards.
f) The factors affecting the biodiversity of orchards operate at a range of scales, from the national scale, for example atmospheric dry deposition, through the landscape scale, for instance the location of an orchard within the matrix of surrounding habitats, to the site scale, such as the grazing management regime in the orchard. Some of these factors also appear to interact and as a result have particular biodiversity outcomes. Atmospheric pollution, continuity of orchards and woodland through time and availability of veteran tree features of fruit trees seem to interact to influence the occurrence of lichen and beetle Indicators of Ecological Continuity.
Ref: English Nature Research Reports. Number XXX. The extent, distribution, biodiversity and management of traditional orchards in England
The habitat surveys of each orchard included recording a sample of orchard trees for girth size and veteran tree features, assessing the species composition of the orchard floor vegetation and the orchard boundaries and noting the presence of associated features such as ponds. Epiphytic lichen and bryophyte species and their abundances were recorded, and, for bryophytes only, all species found on a sample set of individual trees. Fungus species were recorded in spring and autumn from orchard trees, fallen dead wood, the orchard floor and boundary features.
Invertebrate species were recorded during 4 visits to each orchard, by manual searching, suction sampling, sweeping, beating, window flight interception traps and water traps. The main groups covered included Coleoptera, Heteroptera, Aculeate Hymenoptera, Psocoptera, Orthoptera and some Diptera. Broadway Farm Orchards were an exception in that the fruit tree census and invertebrate survey were carried out in 2003, with slightly different methods. Contextual information was gathered from a variety of different data sets including ancient woodland inventories, First Edition Ordnance Survey maps and 2003 aerial photographs. Historical and management information was supplied by orchard owners and managers.
The results were evaluated with reference to assemblages and communities represented and rarity and conservation status of habitats and species, including presence of BAP priority habitats and species and threatened species listed in Red Data Books. In addition, Indicators of Ecological Continuity were identified in the lichen and invertebrate data sets, using published lists of these Indicators.
The overall numbers of species found in the species surveys were: 131 epiphytic lichens, 50 epiphytic bryophytes, 175 fungi and 454 invertebrate species. The sites varied in their diversity for different groups, for example Slew Orchard was the richest for lichens, and Rummers Lane Orchards had the most bryophytes. The sites also had a wide range of communities and associations, for example lichen communities ranged from a community (the Usneion) on very well-lit trees in humid conditions to a deeply shaded bark community (the Pyrenulatum). Numbers of species represented in assemblages varied across sites, for example saproxylic (wood decay) invertebrate faunas were particularly rich in Broadway Farm Orchards, Slew Orchard and Park Farm Orchard, while the highest number of ground layer invertebrate species were found in Park Farm Orchard. Fungi associated with dead wood were particularly varied at Broadway Farm Orchards, Rummers Lane Orchards and Park Farm Orchard. The character of the lichen and invertebrate groups had particular similarities to wood pasture and parkland flora and fauna.
Key conclusions from the results of the orchard surveys are:
a) Orchards are hotspots for biodiversity in the countryside, supporting a wide range of wildlife and containing BAP priority habitats and species as well as an array of nationally rare and scarce species. The wildlife of orchard sites depends on the mosaic of habitats they encompass, including fruit trees, scrub, hedgerows, hedgerow trees, non-fruit trees within the orchard, the orchard floor habitats, fallen dead wood and associated features such as ponds and streams.
b) Different orchards have particular biodiversity value for different groups, for example waxcap grassland may be a feature in one orchard, epiphytic lichens in another and saproxylic invertebrates in a third site. Therefore conservation of orchards as series of sites is required to conserve the full range of biodiversity they support.
c) Orchards, like wood pastures, are dynamic habitats and the habitat they provide for groups such as saproxylic invertebrates will change with the demography of orchard trees in a particular site. Continuity of habitat requires trees at all stages of growth, either within one orchard or a set of orchards in a landscape.
d) Orchards appear to be a significant part of a spatial series or network of habitats at a landscape scale, which are able sustain scarce lichens and beetles, and perhaps other taxa, that require continuity of habitat through time. This network is made up of orchards, hedgerow trees, wood pasture and ancient woodland, all of which are within Biodiversity Action Plans apart from orchards.
f) The factors affecting the biodiversity of orchards operate at a range of scales, from the national scale, for example atmospheric dry deposition, through the landscape scale, for instance the location of an orchard within the matrix of surrounding habitats, to the site scale, such as the grazing management regime in the orchard. Some of these factors also appear to interact and as a result have particular biodiversity outcomes. Atmospheric pollution, continuity of orchards and woodland through time and availability of veteran tree features of fruit trees seem to interact to influence the occurrence of lichen and beetle Indicators of Ecological Continuity.
Ref: English Nature Research Reports. Number XXX. The extent, distribution, biodiversity and management of traditional orchards in England
