and Urban Fringe Sites for Avian Diversity.

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1 The Use of Ecological Restoration Techniques to Manage Urban Introduction and Urban Fringe Sites for Avian Diversity. Patrick Mooney ABSTRACT One of the important roles that ecological restoration may play is that of renewing or supporting biological diversity. Many studies have documented site characteristics that support increased avian diversity. However, until recently, few scientists have understood the importance of urban habitats in supporting regional biodiversity and there have been few models that demonstrate how individual sites might be managed to maximize general avian diversity. This paper reports on research into site characteristics that support avian diversity in the Vancouver region, British Columbia. Key habitats and habitat assemblages, as well as criteria for habitat quality at the patch level, are identified. The study utilized 5 sites in the lower Fraser Basin. The study sites on Burrard Inlet were Maplewood Flats conservation area, Cates Park and Shoreline Park. Detailed habitat mapping in GIS and year round bird surveys were conducted at all sites. Statistical modeling at the scale of the landscape, the site and the patch was then conducted. The model was then validated using Deas Island Regional Park and Alaksen Wildlife Reserve as validation sites after having conducted the same level of habitat mapping on both sites. The model developed was translated into a descriptive model intended for use by conservation managers. From the models developed, the use of ecological restoration techniques to implement site avian biodiversity criteria will be discussed and representative habitat management examples shown. One of the important roles that ecological restoration may play is that of renewing or supporting biological diversity. Biodiversity loss occurs at every scale from local to global. It follows that proposals for stemming this loss must be global, regional and local. Many studies have developed site level measures for the maintenance of avian biodiversity (Easton and Martin, 1998; Freemark and Collins 1992; Hilden, 1965). However until recently few scientists have understood the importance of urban habitats in supporting regional biological diversity and there have been few models that demonstrate how individual sites might be managed to maximize general avian diversity (Vandermeer, 1997; Morrison Marcot and Mannan,1992). The intention of this study was to develop a model of avian diversity that was specific to the lower Fraser Basin and the human modified type of habitats examined. These are urban or urban-fringe habitats sites comprised of deciduous, mixed and second growth conifer forests, clearings and wetlands, and roads and trails. The research responds to a perceived need for a better understanding of urban ecology and the role of human modified habitats in biodiversity conservation. It was hypothesised that the mix of habitats found on the study sites and the characteristics of those habitats would be significantly responsible for the collective avian biodiversity on these sites. The study was intended to show this and to discover which birds, or guilds of birds, use which habitats, so that site level management guidelines to improve or maintain avian biodiversity could be developed. The Province of British Columbia (B.C.) supports 310 species of breeding birds (Campbell, R.W., 1999). This represents about 70% of all the breeding bird species in Canada (Campbell, et al. 1990). B.C. is also an important migratory and staging area for both fall and spring migrations. The research sites are found within the ecoprovince of the Georgia Depression. Although the 1

2 The Use of Ecological Restoration Techniques to Manage Urban and Urban Fringe Sites for Avian Diversity. Georgia Depression comprises only 3% of the land base of the province, 90% of all bird species and 60% of all breeding bird species in British Columbia are found here (Campbell et al., 1990; Easton, 1999). The avian diversity of the Georgia Depression is especially notable in winter. Christmas bird counts on the south coast regularly find 170 species of birds (Ibid.). A checklist of birds for the Vancouver region shows 225 species of birds, of which 59 are not found during the breeding season (Vancouver Natural History Society, 1995). This is also the area of highest urbanization in the Province. Thus, land use management for biodiversity should be an important long-term goal in this region. Study Sites The five sites used in this study are located on the Pacific Coast of Canada in the Province of British Columbia in the Greater Vancouver Regional District, (GVRD). The three study sites used to develop the model are located on Burrard Inlet. These are Maplewood Flats Conservation Area and Cates Park in the District of North Vancouver and Shoreline Park in the Municipality of Port Moody. Two further sites were used to validate the model developed in this study. These validation sites are Alaksen National Wildlife Area in Richmond and Deas Island Regional Park, in the Municipality of Delta. ( See figure 1.) Research Design The outline below explains the research process in a step by step fashion. i. Select three similar conservation sites in the Vancouver Region in which to develop the model, together with two validation sites in which to apply and test the model. ii. Divide the site into patches or plant association polygons based on vegetative inventory; iii. Conduct an inventory of non-vegetative site factors for each vegetative polygon; iv. Develop a year round inventory of avian diversity for each of the three sites; v. Spatially reference the avian and vegetative data in a Geographical Information System database; vi. Conduct statistical and other analyses that examine the relation between avian diversity and site conditions of the study sites; vii. Develop a model of site characteristics that corresponds with species-habitat relations developed; viii. Convert the model from mathematical regressions and other analyses to descriptive management guidelines and explanations; ix. Test the predictive capability of the model on 2

3 two test sites within the region. conservation site, of this type in this region, would be to attempt to have the nine key habitat types of deciduous Results forest, mixed forest, park, salt marsh, freshwater marsh, Habitat Types shorezone, old field, meadow and deciduous shrub. The A series of cluster analyses was conducted using 62 species table shows that these capture most of the FOC1 and found on the study sites during the breeding season, to FOC2 habitats. For example, deciduous forest had 12 determine which habitats had the highest frequency of use. primary use habitats and 12 secondary use habitats from a For each species, the area corrected highest frequency of possible total of 62 primary use habitats and 62 secondary occurrence habitats (FOC1) and second highest frequency use habitats. of occurrence habitats (FOC2) were used in the cluster analyses. This was done because many species use multiple habitats for foraging (Johnston and Odum, 1956; DeGraff et al. 1991) and because at site level, nesting and foraging habitats differ markedly in some species (Degraff et al. 1991). The use of FOC1 and FOC2 in the cluster analyses allowed each analysis to take into account the most used habitats of a particular bird species, whatever the absolute level of occurrence. Birds were divided into guilds i.e. sets of species that exploit the same resources in the same manner, based on their foraging strategies (Ehrlich et al. 1988). See table 3 for a description of these strategies. The results of the cluster analysis were converted first into a descriptive model and then into a series of management guidelines. This provided the landscape level results. Multiple linear regressions were also run to determine the characteristics of highly productive habitats at the patch level. Certain habitat types were found to be more species rich than others. The top four habitat types Shorezone, Mixed Forest, and Old Fields, provided 70% of the weighted FOC totals. This is a strong indication that these four habitat types should be maximized to the degree possible in conservation areas in this region. The key habitat analysis (table 1) indicated that, in this region, it is possible to have the full assemblage of guilds and nearly the full complement of species found on our study sites with less that the full range of habitat types found on the study sites. If the overriding goal were to establish the widest range of species, the criteria for a 3

4 Habitat Type Guild A B C D E F G H I J K L Totals Weighted Totals #Species Ranking Deciduous Primary Forest Secondary Mixed Primary Forest Secondary Park Primary Secondary Salt Primary Marsh Secondary Freshwater Primary Marsh Secondary Shorezone Primary Secondary Old Field Primary Secondary Meadow Primary Secondary Deciduous Primary Shrub Secondary Crabapple Primary Secondary Clearing Primary Secondary Hedgerow Primary Secondary Conifer Primary Secondary Primary Habitats Total Secondary Habitats Total Table 1: Primary Use and Secondary Use Habitats for All Habitat types by Guild 4

5 Habitat Assemblages The research also showed that some habitat assemblages Field, Meadow Guild D (Chiseling) Mixed Forest, support greater numbers of species than others. If it is true that to maximize avian diversity within sites Guild E (Leaf Tossers) Old Field of this type, both primary and secondary use habitats Guild F (Diving) Shorezone for the widest number of species need to be present, then the assemblages of habitats rather than individual Guild G (Swooping) Shorezone, habitats need to be provided.. These were found to be 1) Deciduous Forest/Mixed Forest/Park; 2) Shorezone/Old Guild H (Dabbling) Shorezone, Salt Water field/meadow and 3) Old Field/Salt Marsh/ Freshwater Marsh. All other habitat assemblages provided less than Guild I (Wading) Shorezone, Old Field 5% of FOC1 and FOC 2 habitats recorded. Guild J (Scavenging) Park, Shorezone, Deciduous Shrub Guilds If the goal of a particular conservation manager were Guild K (Frugivorous) Park, Meadow to maximize the number individuals within a particular guild, or set of guilds table 2 shows which habitats would Guild L (Granivores) Old Field need to be maximized. Habitat Type Guild Usage Deciduous Forest Guild A,B,E,G,K,L, Table 3: Habitat Use by Guilds The Patch Mixed Forest Guild A,D A patch is an area (at any scale) that has the same interior Park Guild H,K, characteristics and is differentiated from the surrounding Freshwater Marsh Guild B,C,H area. In this case patches are the areas of different habitat Shorezone Guild C,F,G,H,I,J types within the study sites. The multiple regression Old Field Guild C,L analysis of patch level data established a few key criteria for higher species richness, guild usage and individual Table 2 :Dominant Habitat usage of individuals within usage. High edge to area ratio and larger patch size guilds supported both species and guild richness. Regardless of the season, foliage height diversity correlated with Table 3 shows which habitats would need to be species richness and guild richness. In the breeding maximized for each guild, if the goal were increase the season edge to area ratio and foliage height diversity were number of species in each guild by increasing the primary significantly and positively correlated with the number and secondary use habitats of species within guilds. of nesting territories. In forests, species richness of the canopy trees was a consistent indicator of high frequency Guild Habitat Use of occurrence of number of species and number of guilds. Guild A (Insect Gleaners) The number of food plants correlated with guild richness Mixed Forest in the fall. Guild B (Hawkers) Guild C (Probing) Mixed Forest, Salt The Use of Restoration Techniques Water Marsh The examination of soil moisture and fertility, as well as Freshwater, time since disturbance of each patch in the study sites Shorezone, Old revealed that human disturbance and not the underlying conditions of the site was responsible for establishing 5

6 the site habitat mozaic. If unplanned human disturbance has resulted in a diversity of habitats that supports a rich avifauna, we propose that intentional and controlled human interventions can achieve much more. associations would be most protected from management as they are most difficult and require the most time to replace. Using this criteria, and moving forward in time along the successional continuum, clearing might become Habitat management may be equated primarily with meadow, meadow - old field, old field - deciduous forest vegetation management. This can include clearing, and deciduous forest mixed forest. Habitat types could thinning or burning as well as the use of ecological restoration techniques to enhance habitats or even add entirely new habitat types. In attempting to manage the habitat heterogeneity of a site, managers must asses and be directed by the underlying site conditions such as biogeoclimatic zone, microclimate, and soil moisture and fertility. With this in mind, key habitats and habitat assemblages can be created on site. Existing habitats can be enhanced though the addition of tree canopy species, number of food plants or increased foliage height diversity. also be move backward along the seral stage continuum so that deciduous forest might become old field or old field become meadow. In this way, planned human disturbance (the alteration or maintenance of plant associations through restoration techniques) would be used to create the desired site habitat heterogeneity and habitat assemblage mix. The addition of a wetland is an exception since wetland is an example of a habitat type that is dependent on underlying conditions of site hydrology and not time since disturbance. Its addition would thus represent a change in site level habitat heterogeneity that is independent of seral stage. If not presently available on site, the key habitats may be established through landscape management of the existing vegetation communities. This site enhancement would come about through modification the current plant communities using ecological restoration techniques e.g removal of invasive species, clearing, or thinning, and planting. Plant communities would be moved toward the desired condition using seral stage as a guide. First, all plant associations would be placed on a seral stage Conclusion The study indicates that specific habitat types and assemblages of habitats are significantly and positively correlated with different measures of avian diversity in this region. It also indicates a few patch level characteristics, such as canopy tree species richness or foliage height diversity, that are significantly correlated with higher avian diversity. continuum and then compared to the desired assemblage of plant associations. (Figure 2.) Using ecological restoration techniques, some of the existing habitat patches would be moved forward or backward along that continuum to create the desired habitat assemblages. Ideally, no habitat patch would move more than one seral stage, as this would be more practical from an economic and ecological perspective. Later seral stage mature plant In this region, as in many others of the world, increasing urbanization is reducing habitat and regional biodiversity. If regional and hence global biodiversity is to be maintained, site level management to maintain or enhance biodiversity using ecological restoration techniques will need to be increasingly seen as one of the strategies for this to happen. This is an appropriate application of ecosystem design in areas of the world that are already human modified ecosystems. References Campbell, R.W Pocket Checklist of British Columbia Birds, 2nd Edition: WBT, Wild Bird Trust of British Columbia Special Publication 6

7 No. 1. West Vancouver, WBT Wild Bird Trust of Burrard Inlet, Vancouver Natura; History Society, British Columbia. 2 p. Vancouver B.C. 70p. Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, J.M. Vandermeer, J The Agroecosystem: A Need for Cooper, G.W. Kaiser, and M.C.E. McNall. the Conservation Biologist s Lens. Conservation The Birds of British Columbia: Volume I Biology 11: Nonpasserines Introduction and Loons through Waterfowl. Royal British Columbia Museum, Environment Canada, Canadian Wildlife Service. Victoria B.C. 514p. DeGraaf, R.M., Scott V.E., Hamre, R.H., Ernst, L., and S.H. Anderson Forest and Rangeland Birds of the United States: Natural History and Habitat Use United States, Agriculture Handbook 688. USDA Forest Service. Washington, D.C. 625p. Ehrlich, P.R., D. Dobkin, and D. Wheye The Birders Handbook. Simon and Schuster Inc., N.Y., N.Y. 785p. Easton, W.E. and K. Martin, The effect of vegetation management on breeding bird communities in British Columbia. Ecological Applications 8: Easton, W.E Progress Notes: Preliminary Strategy for the Conservation of Landbirds in the Georgia Basin, February 25, Unpublished manuscript. Canada Wildlife Service Delta. Freemark, K.E. and Collins, B., Landscape ecology of birds breeding in temperate forests fragments. In J.M. Hagan III, and D.W. Johnston (eds.) Ecology and conservation of neotropical migrant landbirds. Smithsonian Institution Press, Washington, pp Hilden, O., Habitat selection in birds. Annales Zoologici Fennici 2: Johnston, D.W. and E.P. Odum, Breeding Bird Populations in Relation to plant Succession on the Piedmont of Georgia. Ecology 37: Kimmins, J.P Forest Ecology. MacMillan Publishing Co., New York. p.387. Morrison, M.L., B.G. Marcot and R.W. Mannan Wildlife-Habitat Relationships: Concepts and Applications. The University of Wisconsin Press, Madison, WI. 343p. Vancouver Natural History Society The Birds of 7