Meadows Matter on Denman
By Jennifer Balke RPBio
Denman islanders have demonstrated once again that they care about the non-human residents of their island! Landowners of 1059 acres (over 8 % of the island) signed up for the first year of the Denman Conservancy Association’s (DCA) 2008-9 Rare Meadow Stewardship program, funded primarily by the federal Habitat Stewardship Program (HSP). This project continues on from the DCA’s initial stewardship effort of ten years ago.
Stewardship is the DCA’s way of honoring landowners who care for native species and of raising islanders’ consciousness of the rich biodiversity of their surroundings. The DCA’s new meadow-stewardship project has four objectives. The DCA sought to identify meadow-species at risk on private land, to create a rare-meadow-species awareness among landowners and the community, to gain information and share ideas about their ecology and habitat needs and lastly to inspire and assist landowners in adapting their land use for the mutual benefit of all. This new stewardship initiative was focused on rare species in meadows. But Denman is known mainly for its forests and wetlands. So, a rare ‘meadow’ species program on Denman comes with a quite a story.
A colorful checkered flutter began this phase of the Denman stewardship story, but to be complete, we probably need to begin even further back. At the turn of the millennium, Denman lands had changed dramatically. One third of the island’s covering blanket of vibrant Douglas-fir forests was gone. In its place, around the homes, gardens and farms of islanders were thousands of acres of raw clear-cuts1
Wildlife species on Denman changed with the vegetation conversion. Removal of the forests led to the demise of myriads of forest-dwelling species. Creation of the vast open spaces of dry shrubs and wet meadows resulted in the proliferation and immigration of sun lovers and open-land species. The Taylor’s checkerspot butterfly Euphydryas editha taylori was one of those emerging species.
Taylor’s checkerspot butterflies, affectionately known as Cspots, once occupied Garry oak meadows and open areas of SW Vancouver Island and the Gulf Islands. Populations dwindled to a last stand on Hornby Island before being declared “extirpated” or gone from Canada about 2001. Thus, their emergence in Denman Island clear-cuts in 2005 was greeted with both joy and amazement. The wet shrubby sites where the butterflies thrived didn’t look much like Garry oak meadows, but this focused additional conservation attention on those ‘vernal pools’ of the south coast meadows. Meanwhile biologists studied Cspots on Denman.
Learning about the Cspot life cycle timing and stages on Denman was the first goal. Identifying where the Cspots had breeding populations was essential for their conservation. So, biologists searched for the spring or ‘post-diapause’ larvae. Fortunately background information was plentiful, as Checkerspots, worldwide, are one of the most studied groups of butterflies. The recently published “On the Wings of Checkerspots” textbook2 is evidence of the scientific interest. As more breeding sites were identified on Denman, the focus turned to conservation. Stewardship for all these private land parcels seemed the best approach.
The DCA’s previous success with a two-year private-land stewardship program was the inspiration. From 1996 to 98, landowners of 114 properties signed stewardship pledges committing to protect native species for 1158 acres of Denman Island. This project had all the usual rewards and the exhausting aspects of landowner contact and stewardship education, with which stewardship groups are very familiar. Island groups also know the changing nature of Gulf Island land-ownership. Repeated landowner-turnover is due to both the ever-rising property values and the inability to tolerate rural life-styles combined with ferry travel. This reality, together with a lack of institutional support for BC’s natural history, and an amazing paucity of wildlife information, even at the species presence or absence level, makes the need for community-based natural history education a never-ending necessity.
So ten years after the DCA’s first major stewardship effort, the meadow stewardship project began, with the charismatic Cspot as the flagship species. In the new revived-stewardship program, rare meadow species are emphasized in the landowners’ pledge3 and the subsequent plans and land-use records. Only properties with rare-meadow species are included in this project, and so far, the overlap with the previous project is minimal (3% of acreage pledged). The rest of the island community is included in all of the educational aspects of the project, and the potential for habitat protection increases as new landowners with rare meadow species, especially Cspots are continually coming forward.
The aims of the Government of Canada’s Habitat Stewardship Program are to conserve and to assist the recovery of ‘species at risk’ and their habitats. During the Denman project, the DCA’s list of ‘meadow-species at risk’ has grown to 18. Included with the Cspots are five other invertebrates, one reptile, one amphibian, eight bird and one mammal species4. While local biologists learn more about the Cspots, they also identify other rare species and can assist landowners in conserving these species and their habitats.
As the DCA’s new stewardship program enters its second year, the Cspots are flying again. Throughout May, they take flight for their short ten days to 2 week life as butterflies in Denman clear-cuts and fields. Stewardship is focused on both the dry open sites as well as the wet meadow habitat. Biologists have identified all phases of the Cspot lifecycle, from mating and laying of eggs, to the birth of summer or ‘pre-diapause’ larvae. These tiny caterpillars gradually forage further from their initial communal nets, usually wrapped around Marsh speedwell plants Veronica scutellata, on the ground. The larvae eat these plants and move on for more. Then, they disappear!
The main life-cycle/habitat question at the moment, is where the caterpillars ‘sleep’ for the late fall and winter. By February, they emerge from these sleeping sites, and this year, their early appearance suggests that they enjoyed our cool, dry and sunny spring. These fuzzy black caterpillars, with eight bright-orange spots along their back, are distinctive and active! They travel singly or in groups, eating speedwells and plantains, shedding skins and growing larger. Then, the caterpillars find a protected spot under a leaf or on some man-made habitat and become a gorgeous spotted pupa. They emerge a couple of weeks later to take wing, to nectar on any available flowers and to start the cycle again.
As usual with wildlife, prediction is difficult and understanding is never complete. Biologists don’t know if these Cspots were always on Denman, and if they were just waiting for more openings to prosper. They don’t know if these new clear-cut habitats are particularly good for them and whether they will successful colonize the seemingly suitable Denman farmlands, if enhancement ideas are attempted. ‘Meadows’ are such a rare thing for the coastal Douglas-fir ecosystem. Except for wet, rocky or dune-type sites, forests would prevail over the coastal habitats. First Nations are responsible for creating and managing the magnificent expanses of coastal Garry Oak meadows and the wealth of species that once colonized them. Turning present-day coastal lawns to Garry Oak meadows is one potential answer to protecting a whole ecosystem of species including Cspots!
Meanwhile, populations of animals fluctuate for so many reasons. Disease, parasites, predators and density-dependent factors, for these Cspots, are still unknown. The DCA’s stewardship program will continue to monitor the Denman population and to protect and enhance available habitat. However, single site populations are extremely vulnerable, and as last year’s Canadian stamp depicted…. Denman’s Taylor’s Checkerspot is truly one of Canada’s Endangered Species.
2 Erhlich, P.R., & Hanski, I. (Eds.) (2004). On the wings of checkerspots. NewYork: Oxford University Press, Inc.
3 “Denman’s Stewardship Pledge for rare meadow species is a commitment to the future – a commitment that continues to broaden Denman’s sense of community to include the natural world and the natural features that sustain all life.
As part of Denman’s Rare Meadow Species Stewardship Project, we pledge:
* to respect the biological diversity of Denman Island by being aware of and showing sensitivity to the rare meadow species of wildlife and plants that inhabit our property,
* to support the rare species stewardship plan that we describe for our land and to agree if possible, to seek the Project’s advice, when major changes are planned in the use of the land,
* to support the continuity of the Project by informing subsequent owners of our property of the Stewardship Pledge.”
4 barn owl Tyto alba, barn swallow Hirundo rustica, blue dasher Pachydiplax longipennis, coastal wood fern Dryopteris arguta, common nighthawk Chordeiles mino, common woodnymph Cercyonis pegala incana, dun skipper Euphyes vestries, great blue heron Ardea herodias fannini, northern goshawk Accipiter gentilis laingi, olive-sided flycathcher Contopus boreali , peregrine falcon Falcoperegrinus, red-legged frog Rana aurora, Taylor’s checkspot Euphydryas editha taylori, Townsend’s big-eared bat, Corynorhinus townsendii, western painted turtle Chrysemys picta bellii, western pine elfin Callophrys eryphon sheltonensis, western pondhawk Erythemis collocate, western screech-owl Megascops kennicottii kennicottii.
