If you have been gardening for a couple of decades or more, you will have noticed that the climate is changing. Shifting weather patterns can bring increased rain or increasing levels of drought, and higher or lower temperatures for the season. In the future, we may not be able to grow the things we do now. Soon, many native plants may no longer be able to survive in their historic ranges, and the wildlife they support will be decimated. However, your garden can have a big impact on your local environment and can help protect local wildlife. No matter how big or small, your garden:
Improves Air Quality
Plants take in carbon dioxide from the atmosphere through their leaves and expel oxygen, as well as helping to remove toxins from the air. Your plants will help the local atmosphere.
De-toxifies the Ground
Plants also absorb through their roots, including chemicals and heavy metals in the soil and groundwater, gradually converting it into healthier ground. Naturally, this is not good for the particular plant, but a sick plant can alert you to soil problems.
Trees can absorb and store carbon pollution from the atmosphere. If every one of America’s 85 million gardening households planted just one tree in their backyards those trees would absorb more than 2 million tons of CO2 each year. 
Shade trees planted near your home can reduce energy used for cooling in the summer.
Reduces Your Carbon Footprint
Growing some of your own food will reduce your carbon footprint – fewer trips to the shops, no food-miles, less waste.
Prevents Soils Erosion
Plant roots bind soils together, making them less likely to wash away.
Replenishes Nutrients in the Soil
Topsoil is created by organic materials, such as leaves, that fall from plants. Decaying organic material provides nutrients, and some plants fix nutrients into the ground.
Helps to Reduce Noise Pollution
Vegetation absorbs sound, so hedges, trees and shrubbery reduce noise pollution.
The more plants and trees you have in the garden, the more you will be encouraging the local wildlife, especially if you include native plants. Birds, insects and other animals need them to survive. If you live in a built-up area, providing natural spaces for insects, birds and small mammals is vitally important.
MORE YOUR GARDEN CAN DO FOR THE ENVIRONMENT
While almost every garden helps the environment, you can do even more:
Plant Native Species
Including native plants in your garden help to maintain important pollinator connections and ensure food sources for wildlife. You can plant shrubs with berries for birds, plus bee and butterfly friendly plants.
Rewild Part of Your Garden
This means giving part of your garden back to nature, and letting nature do its thing – including letting the native ‘weeds’ (I call them wildflowers) grow, which provide food for the local insects. Remove any non-native plants from this area. Increasingly, over time, it will become a complex ecosystem.
If you can’t do this, avoid large, paved areas and artificial grass.
Create a Wildlife Pond
A garden pond, whether large or small, can be a haven for wildlife, and the wildlife will find it pretty quickly. It is vital habitat for wetland creatures such as frogs and dragonflies, and great for many species of insects, birds and mammals. Remember to make one side shallow, so that frogs and small mammals can climb out. Have some shade over part of the pond to reduce algae growth, but part should be in full sun. Fill it with rainwater if you can, but if tap water must be used, be sure to let it naturalise for at least a week before adding any forms of life, including plants.
Build Insect Hotels
Insects pollinate your plants, aerate the soil and provide food for birds. The beneficial insects in your garden need somewhere to hibernate for the winter, so why not make them their own five-star bug hotel? It is best to do this in the early autumn, when there is plenty of suitable material available, such as dry leaves, twigs, hollow stems, dead grass, pinecones and bits of bark, and it will give the insects time to settle into their new home before the cold comes. There are some great ideas online for making bug hotels, and kids will love to get involved. Otherwise, you can simply make a log pile in a shady area for centipedes, woodlice and beetles or a pile of pinecones and leaves is good for ladybirds and lacewings.
Have Holes in Your Boundary Walls
It is important for wildlife to be able to move around from one place to another. A hedgehog, for example, can travel up to a mile in a single night, looking for food. One of the reasons for declining populations is the high, solid fences that some people have around their gardens. You can help by putting small holes in the bottom of your fences (as long as your neighbour agrees).
Reconsider Your Garden Lighting
The blue and white toned lighting often used in gardens is one of the major factors in biodiversity collapse as it confuses insects. Leave areas of your garden in darkness, and don’t use your lights all the time. You can buy red-tone lights that don’t affect insects as much. Try to use energy efficient products in your garden; replace energy hungry outdoor bulbs with LEDs, or better still, use solar lighting.
Reduce the Use of Power Tools
Avoid using power tools as much as you can. Using a gasoline-powered mower for an hour pollutes 10 to 12 times more than the average car.  If you can, switch to hand tools and push-lawnmowers. The air from leaf blowers kills small creatures, and I would urge you not to use them at all.
Install a Rain Barrel
Install a rain barrel to collect free rainwater, and your plants will like this much better than tap water. You can prevent water loss from your plants by mulching around them.
Make a Compost Heap
Building a compost heap (or using a purchased compost bin) is a wonderful way to reduce your impact on the environment and create a great free source of nutrients for your garden. You can add virtually all food waste and organic matter to your compost bin – fruit and vegetable peelings, leftovers, twigs, leaves, non-seeding weeds, eggshells, card egg boxes, cardboard, tea bags (if they don’t contain plastic), coffee grounds and even your old wool jumpers. I also add the sawdust bedding and poo cleaned out from my chickens to mine. You will need to add something to ‘activate’ your compost (i.e., get everything working) and for this you will need to add soft greens, manures or urine (yes, you can use your own, though male urine is said to work better than female).
Don’t Rake Your Leaves
While you might need to remove slippery leaves from paths, in the rest of the garden fallen leaves provide a habitat for many over-wintering wild creatures. Some beneficial insects lay their eggs in leaf litter, and by raking up the leaves you will be curtailing their life cycle. If you do rake them up, put them on the compost heap, or bag them and save them to use as mulch in the spring. Lay a mulch of fallen leaves around plants (about 3 inches deep) and allow it to rot down into the soil. The earthworms will love it, and you will be adding nutrients and organic matter into the soil. Leaf mulch maintains soil moisture and soil temperature, prevents weeds, soil erosion and compaction.
No Autumn Clean Up
Abandon the big autumn clean-up of the garden. Leave the fallen wood, leaves and seed heads where they are till spring, as the bird, insects and other wildlife need their shelter and food over winter.
Ditch the Chemicals
In the twentieth century, chemicals were promoted as an easy technical solution to all cultivation problems – synthetic fertilizers, pesticides and weedkillers became commonplace not only on farms, but also in domestic gardens. We now know that these products are having a disastrous effect on ecosystems, wildlife and human health. 
Pesticides from treated plants and soil reach surface water through runoff. More than 90% of water and fish samples from all streams in the US contain one or more pesticides,  and wild salmon are swimming around with dozens of synthetic chemicals in their systems. In the UK half of rivers and freshwaters exceed chronic pollution limits and 88% of samples showed pesticide contamination.  We are now seeing the wholesale pollution of most of our streams, rivers, ponds and coastal areas from agri-chemicals.
Chemical fertilisers are equally problematic. When the excess nutrients run off into our waterways, they can cause algae blooms that are sometimes big enough to make waterways impassable. When the algae die, they sink to the bottom and decompose in a process that removes oxygen from the water. Fish and other aquatic species can’t survive in these dead zones.
It’s time to dump the chemicals and look for natural solutions. If you look after your plants well, you won’t need them. Choose plants that are suited to the growing conditions you have – native plants will thrive better. Allow them plenty of space, and prune where you need to. Provide good drainage, mulch your plants to keep down weeds and reduce the need for watering. Regularly hand-weed and hoe. Wash off pests with the garden hose or try one of the aphid sprays overleaf. Greenfly can be dusted with diatomaceous earth (available online). Investigate companion planting to reduce pest invasion. If you grow vegetables, rotate your crops on an annual basis. Be prepared to accept a low level of pest or disease damage on your organic plants.
 https://www.nwf.org/Our-Work/Environmental-Threats/Climate-Change/Greenhouse-Gases/Gardening-for-Climate-Change, accessed 13.10.21
 https://policy.friendsoftheearth.uk/opinion/effects-pesticides-our-wildlife, accessed 6.10.21
 Aktar MW, Sengupta D, Chowdhury A. Impact of pesticides use in agriculture: their benefits and hazards. Interdiscip Toxicol. 2009;2(1):1-12. doi:10.2478/v10102-009-0001-7
 https://www.scientificamerican.com/article/how-fertilizers-harm-earth/ accessed 6.10.21
 https://policy.friendsoftheearth.uk/opinion/effects-pesticides-our-wildlife, accessed 6.10.21