Dr. Pamela Wright
On S’Dayes (Pender Island), we are blessed with a diverse suite of ecosystems from rich intertidal areas to nearshore kelp forests, coastal Douglas Fir ecosystems, wetlands and small lakes, like Gardom Pond and Roe Lake, and others. The diversity of these ecosystems, like in human communities, gives them strength. However, these diverse ecosystems are insufficient if they are not connected. Ecological connectivity is the unimpeded movement of species and the flow of natural processes that refresh and regenerate ecosystems. Connectivity is critical at very small scales, from the mycrorrhizal fungal networks that connect trees in the soil, to rough-skinned newts who travel overland in spring to ponds and lakes to mate underwater, and at very large scales with migrating grey whales who move from Baja up to the Bering Sea and black oystercatchers who come south in the winter to over-winter around the shorelines of Pender.
Unfortunately, our settlement patterns, land use, and transportation break up habitats, ecosystems and landscapes (at all scales) in terrestrial and marine environments and disrupt ecological connectivity. The disturbances can be permanent or ephemeral. Invasive species, pollution, over-extraction of natural resources, roads and other linear corridor developments, recreation impacts, habitat loss through land conversion and human settlement are just a few of the challenges.
Human-dominated land and seascapes act as a filter where some species can pass freely and others cannot. Moreover, the more we have smaller, distinct subpopulations of species, the more unfit they are and the more at risk from disturbance – all leading to extinction.
The scale of the problem is very significant. Over 75% of global terrestrial ecology (Venter et al. 2016) has been directly modified, and 87% of marine biomes are fragmented by overfishing, transportation, nutrient runoff and pollution (Jones et al. 2018). Globally, the Living Planet Index (LPI) reports that over 60% of vertebrate species monitored are significantly declining, and the LPI for Canada shows similar results. All of this is without the additive challenges posed by climate change – accelerating, magnifying and diversifying the threats biodiversity faces.
Protected areas, like national and provincial parks, and private land conservation areas like Medicine Beach and S’Dayes Flycatcher Forest on Pender Island are not enough alone. Canada has legally protected only 15% of our terrestrial environments and just around 11% of marine environments – less than half of the commitments that we have made globally to protect 30% of the country by 2030.
The reality is that even if we were to meet the 30x30 targets, species loss would still decline precipitously. In order to safeguard species and ecosystems, we need to manage these protected areas well, and ensure that the lands surrounding these areas, where our communities, agriculture and resource use occur, must allow movement for species and ecological processes. We need our yards, our neighbourhoods, our cities, our farms and our managed forests to provide suitable habitat and be permeable to movement.
As climates change even more drastically, species will need even more room to move. Many species will need to move northward or elevationally to keep up with the climate environments that are favourable to them. Only some species will move fast enough and be flexible to track these changing climates.
Climate Change Refugia. Credit: USDA Forest Service
So what does ecological connectivity look like on Pender? If we imagine a Pender Island before it had a significant settler human footprint, the diverse mosaic of habitats would have been highly permeable or ‘connected’. Plants and critters would have had preferred habitats where they could fulfill most of their life requisites but were able to move through (with more or less ease) the other habitats on daily movements (for example, in search of food), to find better or bigger habitat patches, on seasonal movements (e.g., newts emerging from overwintering sites and movement to breeding ponds), in response to disturbances (wind throw on one aspect of the island might create opportunities for cavity nesting birds to move in) or in response to drought or persistent damp conditions.
If we add an industrial, or settler, human footprint, of course it becomes more difficult. Not only is there less available, or less suitable habitat, but there are significant barriers to movement: from newts crossing roads; to agricultural fields that create crossing barriers for voles and moles now exposed to raptors; to a hostile ecological barrier of broom; to forest birds disturbed by dog walking and other recreation use along forest paths and beaches. So what are some implications of the more fragmented habitats we have now?
Roads and trails fragment the forest interior habitats that forest birds need and lead to an increase in nest predators who occupy the edges for up to 75-100 meters into the forest on either side.
Our homes and businesses not only result in significant direct habitat loss but also harden the landscape making it hostile to the movement of species like endangered sharp-tailed snakes, newts, and garter snakes.
Invasives like broom, daphne and other spurges, hawkweed, and Himalayan blackberry fragment and disconnect habitat by biotically homogenizing or simplifying ecosystems, and many of these invasives create habitats inhospitable to native species.
Human presence in the numbers and patterns with which we use land leads to hyperabundant species like Columbian black-tailed deer that persist in populations not only unhealthy to themselves but resulting in decreases in native vegetation and connectivity.
Light from our houses and businesses interrupts connectivity for birds, bats, and bugs.
Hiking and biking negatively affect breeding bird densities for many species of forest birds, increase the risk of nest predation of songbirds, decrease singing activity, parental attentiveness, and feeding patterns
Bird Corridors - Migrations in Motion. Credit: https://maps.tnc.org/migrations-in-motion/#4/44.62/-96.20
The good news is that there are ways we can live and enjoy Pender while creating a more permeable landscape. In addition to Gulf Islands National Park, the community members who worked with the Conservancy to acquire properties like Medicine Beach, Brooks Point, and S’Dayes Flycatcher Forest amongst others have helped protect some critical core habitats. These lands and other recreation properties on the island are a good start at protecting core habitat areas.
Right now, PICA is actively working to purchase a 45-acre (18 ha) parcel of diverse forest, the Kelá_Eke Kingfisher Forest, in the Razor Point Road area. This amazing property includes marine shoreline, upland forest, and wetland habitat. It will provide critical core habitat for plants and animals and connectivity from the shoreline to ridge line and to adjacent blocks of forest habitat in the National Park. This provides connectivity now but will also serve as a refuge and connectivity pathway as the climate changes. You can help. Join the campaign to protect Kingfisher online at https://www.penderconservancy.org/kingfisher-forest or in person at the Pender Island Conservancy Nature Centre in Hope Bay.
You can also help by asking yourself questions like:
What kinds of connectivity are important in my yard/neighbourhood, including horizontal and vertical connectivity, above ground and below ground, daily movement connectivity and seasonal connectivity?
What habitat complexity can I provide on my property/neighbourhood?
How can I provide habitat bridges through/across my property?
Can I provide critical nesting/breeding habitat as well?
How can I help manage invasives and create reservoirs of native species?
What climate refugia can I provide?
Can I make my yard or neighbourhood more resilient to climate extremes by strengthening its ability to:
Absorb rainfall
Store rainfall for slow release (e.g., with large, coarse woody debris)
Safely, slow down water passage
Allow for pooling of water
Soften the edges of our yards so that there are no abrupt edges to strengthen their wind firmness
Wildlife crossings at big and small scales. Left picture is one of the 6 wildlife underpasses and 38 overpasses in Banff National Park. Right hand image is of a wildlife tunnel in Pacific Rim National Park Reserve for salamanders and frogs
We need big core areas that protect important and diverse ecosystems and habitats, but we also need to focus on ecological connectivity on the lands between these core areas.
Suggested Connectivity Resources