Creating Habitat and Biodiversity

Paul Alfrey - The Balkan Ecology Project
Friday, 7th February 2020

Biodiversity and Habitat - How we may support biodiversity as we grow food and other resources in our regenerative landscapes.

Last season we started a new survey in an attempt to gain an understanding of the biodiversity within various habitats of a regenerative landscape. During this article I'll introduce the garden we carried out the surveys in, overview the habitat types within the garden that we looked at, present the survey protocol, and share the results from the late Summer Survey.

So let's start with what's the point of recording biodiversity in the first place.

Why do we need to record biodiversity in the first place? 

Our project mission is to develop and promote practices that can produce food and other resources for humans while enhancing biodiversity. To encourage biodiversity in our gardens, we include a variety of habitat into the landscape design, including native wild habitats (at various stages of succession) and cultivated habitats. The gardens are, essentially, a mosaic of habitat. Seeing as we are looking to enhance biodiversity within our gardens we must have the means to record the diversity within the various habitats. Our aim is to use this information to guide our land management practices specifically in terms of what ratio of land we should dedicate to wild native succession habitats and to what degree we can work within these habitats without disturbing the suitability of the habitat for other organisms i.e without disrupting the biodiversity. Furthermore, we would like to see how our cultivated habitat types i.e annual and perennial polyculture, compare to the wild habitat.

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Various habitats within our Polyculture Market garden Plot - Aponia (Aquatic habitat not included). See here for this gardens location on our project map. For habitat, description see below. 
To do this completely we would need to include plants, fungi, animals (invertebrates, birds, mammals, reptiles, amphibians) and microbes. Quite a task by any standard and currently beyond the capacity of most people and projects, including ours. Actually, we do have good general records of plant, mammal, bird, reptile and amphibian species that inhabit our gardens (Dylan has started to add these to our website that you can find here if you are interested). For seasonal surveying and tracking changes over time, I believe that a good way to assess the general biological diversity is to study invertebrate diversity i.e spiders, insects, bees, etc. Invertebrates largely rely on plants for food and shelter and invertebrates are often relied upon by birds and mammals further up the food chain as they make up a significant portion of the larger animal's diet. It seems that within our environment, at least when you have high levels of invertebrate diversity, you will likely have high levels of plant and larger animal (vertebrate) diversity too.
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As a side note, I believe strongly that a global standard for accurately recording and accounting for biodiversity is probably the most important factor for transitioning into regenerative agriculture and without this standard, regenerative agriculture will most probably remain a trendy, marginal application meeting only a tiny percentage of global food demand. With a global biodiversity recording and accounting standard established it can be used across the planet to provide incentives for activities that are enhancing or at the very least sustaining biodiversity levels and withdraw incentives and issue penalties for those activities that result in lowering biodiversity. This is a huge discussion beyond the scope of this post and the development and application of such a standard is something that humans, with skills that I certainly do not possess, could develop and would involve engineering new hardware and software technologies and the coordination of a massive global academic and political collaborative effort. Certainly not beyond our collective reach but probably one of the tougher challenges of our time. 

For now, I will focus on what I can immediately do and so have aimed to develop a super simple low tech method to survey invertebrate diversity within our garden habitats. The goal of the survey is that it should be simple enough that anyone can use it and that the data collected should be good enough to draw some useful conclusions.
First, an overview of the garden where we are carrying out the surveys.

Garden Overview

Location: Shipka, Bulgaria, Southeast Europe
​Climate: Temperate
Köppen Climate Classification - Dfc borderline Cfb
USDA Hardiness Zone: 5b (conservative) - 7a (risky)
Latitude: 42°
Elevation: 565m
Average Annual Rainfall: 588.5mm
Prevailing Wind: NW & NE
Garden Name: Aponia - Polyculture Market Garden
Garden Location on our Project Map - See here 
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Within this garden, we have identified a number of pre-existing habitats and have created some habitats. What follows is a description of those habitat types within the garden.

Habitat Types 

Habitat types refer to distinctly different regions within an area and in this case, are determined by the composition and age of the plant species within those areas. We have identified six  habitat types within this garden that fall under the following categories, Wild HabitatSemi Wild Habitat, Semi Cultivated Habitat, and Cultivated Habitat.
Wild Habitat 
Late Scrub
Early Scrub
Semi Wild Habitat
Mixed Species Meadow
Semi Cultivated Habitat
Mixed Species Hedgerow
Cultivated Habitat
Perennial Polyculture
Annual Polyculture

It should be noted that the cultivated habitat types as presented above were abandoned horticultural land and were heavily grazed by tethered horses before we started the development of the garden. This land, if left unattended, would succeed to a habitat very similar to the other habitats on the site, namely Mixed Species Meadow to Early Scrub to Late Scrub and would eventually form Woodland. When working with habitat types within your landscape, it's important to have a good understanding of the successional pathway of the vegetation in order to properly appreciate the dynamics of the land and the species that inhabit each successional stage. This information will help you manage the land, specifically the potential for biodiversity, properly.

An excellent classification system for habitat type has been developed, The UK Habitat Classification, and can be downloaded from the bottom of their homepage here. Our classification system follows this broadly but I have made some adaptions to make it more relevant to our polyculture design, implementation, and management strategy. 
The map below shows these various habitat types within our eight-year-old Market Garden, Aponia.
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Habitat Type Detail 

The following information only includes a sample of the diversity of plant species within each habitat for the month that we carried out the survey i.e August. We intend to make a full record of all the species in each habitat across the season (to account for the seasonal succession of annual and ephemeral species) next year during our Polyculture Study 2020 and provide labeled illustrations of the placement of plants within the cultivated habitats.
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Micro habitat 

Our garden designs also include a variety of microhabitats such as rock piles, small and large ponds, gravel pathways, stick piles, rotten log piles, helping mats, tree stumps. These are often placed within a variety of habitat types and are not considered in the survey. A survey of our microhabitats will make a good continuation of this study for the future.
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You will find a full education on integrating and managing habitat in your garden/farm/landscape on our Polyculture Design -  Online Interactive Course - How to Design, Build and Manage Polyculture for Regenerative Landscapes, Gardens and Farms. We have multiple sessions during the course dedicated to habitat and cover extensively and coherently how to identify habitat types on your land. We will also cover ecological succession, how to identify the typical flora and fauna species of your habitat, how to make habitat maps, how to develop, maintain and manage habitat, and look at the productive potential of each habitat.
So now let's look at the Survey Design and how we aim to gain a measure of biodiversity within each habitat type.

Our Survey 

Each of the six habitat types are surveyed for the number of unique species observed in two pitfall traps within each habitat type and 10 canopy observations at different locations within each habitat type. These surveys are carried out at the same time every first and second Monday and Tuesday of the months April to September over a period of three years.
The time and date - weather conditions (cloud cover - temperature - wind ) and rainfall received since the last survey are all recorded before we start. (Rainfall received since the last survey is only recorded for weeks 2 and 3 of each month.)

The Pitfall Traps

Two pitfall traps are set within each habitat type. Each trap is labeled for recording purposes. The traps are set on Monday morning, left overnight and emptied onto white trays on Tuesday morning.


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The pitfall traps labeled ready to take a position in the habitats
The number of unique species is counted within each trap and an average of the two traps per habitat is taken to provide the average number of unique species found within each habitat type. After emptying the traps, lids are placed on the jars and the survey is repeated the week after. The below image shows the locations of the traps within each habitat type. 


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Shahara Khaleque made a couple of videos that show the habitat types and how we undertake the pitfall traps surveys. You can find part 1 here and part 2 here.

Canopy Observations 

A 50m trail within each habitat is determined as shown by the red dotted lines in the below image and 10 locations labeled 1-10 are fixed 5m apart along the trail.
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At each location the observer stands and observes within their 2-3m field of vision (without turning the head) for two minutes: one min standing, one min kneeling and recording the number of unique species they can see on the plant vegetation and on the ground.
Protocol Invertebrate Survey - Canopy Observations 
  1. Find your starting mark
  2. Set timer to two minutes
  3. Face the habitat and count the number of different species* within your 2-3m field of vision without turning head. One minute standing and one minute kneeling 
  4. After two minutes walk to the next mark 
  5. Repeat 2-4 until you have completed 10 surveys. 
Species you have seen in previous locations are counted again (start new species-count after every change of location).
*Different species = Do not count individuals, count visibly different species, e.g. 3 black ants and 1 red ant = 2 species. 1 big black spider and 1 small black spider, hard to say if it is young/old or male/female = 2 species. 1 small spider and 1 big spider that are clearly the same species = 1 species.
Flying species: Bypassing flying insects do not count. Insects hovering (to feed on nectar/pollen) or landing in your field of vision do count.



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Here is Shahara taking canopy observations in the Early Scrub Habitat
To account for discrepancies between individuals' vision and interpretation of what should be counted as individual species, we undertake the canopy survey twice with a different person counting a different habitat and rotate who does which habitat each week. 
The data for both surveys are recorded on printed sheets as seen below.
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How we process the data 
The data gathered for all of the surveys in each habitat is averaged. For example, in the Late Scrub, if five unique species were counted in pitfall trap one and three unique species counted in trap two, the total record for pitfall traps in this habitat would be four. Likewise, if eight species were counted during canopy observation one, and four species were counted during canopy observation two, the total record for the canopy observations for this habitat would six species. 
We then take an average of both the pitfall trap and the canopy surveys within each habitat for the overall species diversity of each habitat type. 
Finally, the results from each month are averaged to give us a monthly average of the number of unique species in each habitat and the monthly results are averaged to give a season average for each habitat.

The Results 

The below table shows the number of species we recorded from each habitat type in weeks 1 2 & 3 of our August Survey. Click on the links to see the individual records of the Pitfall Traps and Canopy Obs for Week 1Week 2 and Week 3.
Weeks 1-3 - Results Summary - Based on the average number of unique species counted in Pitfall and Observations
Week 1 - 1 day after significant rainfall Week 2 - 8 days after rainfall Week 3 - 15 days after rainfall
Rank Habitat Number of Species Rank Habitat Number of Species Rank Habitat Number of Species
1 Annual Polyculture 7.575 1 Annual Polyculture 3.775 1 Annual Polyculture 3.825
2 Perennial Polyculture 6.5 2 Mixed Species
Meadow
3.425 2 Mixed Species
Meadow
3.475
3 Mixed Species
Meadow
5.8 3 Early Scrub 2.9 3 Early Scrub 3
4 Mixed Species
Hedgerow
4.575 4 Perennial Polyculture 2.525 4 Perennial Polyculture 2.3
5 Early Scrub 4.2 5 Mixed Species
Hedgerow
2.2 5 Mixed Species
Hedgerow
1.875
6 Late Scrub 1.85 6 Late Scrub 1.7 6 Late Scrub 1.575
The August survey revealed that the Annual Polyculture was the habitat that showed the highest levels of unique invertebrate diversity and that Late Scrub showed the lowest levels of diversity.
Total - Average for each habitat (rounded up)
Rank Habitat Number of Species
1 Annual Polyculture 5.0
2 Mixed Species
Meadow
4.2
3 Perennial Polyculture 3.8
4 Early Scrub 3.4
5 Mixed Species
Hedgerow
2.9
6 Late Scrub 1.7
Table showing the Number of unique species recorded within each Habitat Type
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It's obviously too early to draw any conclusions based on one month of surveying but it looks like a promising start for our cultivated habitats. I think a significant part of the reason why invertebrate diversity was higher in the cultivated areas is that they are irrigated at least bi-monthly and water is probably the single most important factor concerning biodiversity especially the ground invertebrates. I expect that the early spring surveys will tell a different story with the abundant rainfall bringing life to the Scrub areas. The mixed-species meadow results were as expected and even without irrigation were teaming with flying insects taking advantage of the pollen and nectar resources on offer.

Shortcomings of the Surveys 

Our aim is to keep the survey as simple and replicable as possible without sacrificing the validity of the data. It seems to me that the barriers to entry for the majority of people when carrying out such a survey will be costs, expertise and time. I believe we have certainly addressed the cost and expertise barriers with the design of this survey and have reduced the amount of time needed to carry out the survey to something that is quite manageable providing you have a small team of 4-6 people that are willing to give 40 minutes or so of their time 12 times a year and you are prepared to co-ordinate the group and process the data. (I've designed the sheets to do the math and punch out the results so all you need to do is enter the data.) It's also possible for one person to complete the survey alone but it's almost certainly going to be tedious. Of course, surveying six habitats is not necessary and you could carry out the survey on however many you may have. Let's have a look at the shortcomings of the survey.
Here are the main shortcomings we have identified so far. If you can see more please do let us know and better still provide a solution that fits within the aim of the survey design. 
  • Perhaps the biggest shortcoming is that we do not gather information about the species. For future surveys we will develop a simple category ID list for i.e ants - bees - winged insect - snail - slug - beetle, etc. based on the most common species in order to have a better understanding of the organisms within each habitat and hopefully to identify how these organisms relate to productive capacity i.e pests, borgs (beneficial organisms), neutrals. 
  • As we are not identifying the species and have limited knowledge of entomology we may be counting unique species when in fact they are male or female, larvae/adult or at different instar stages. I expect reliable identification apps for invertebrates will be available in the not too distant future, at least for identification to the group level which can be very helpful for our purposes.
  • Because we are not using ethanol in the pitfall traps (commonly used to kill what falls in the traps), it's possible that predators may fall in and eat prey species before we can count them.
  • The canopy observations do not account for nocturnal invertebrates
  • The canopy observations from the habitat types with tall shrubs and trees do not account for invertebrates in the higher canopy. We could use a 'beating tray' observation for this but for some of the habitat such as early scrub and hedgerow, it will be difficult to set this up. 
  • It could be misleading to think that just because some of the wild native habitats have lower invertebrate diversity that it is of lower value as in some cases uniformity of habitat type, although,  may not support a wide range of invertebrate diversity could be essential for certain mammals or bird that may only inhabit the area at certain intervals of the year. More study and understanding of how different organisms relate to the habitat type is required before making decisions on altering the habitat.
  • Obviously, the biodiversity metric alone cannot be used to signify environmental health. Soil health - water quality - air quality and the productive capacity in terms of meeting human needs and the stability/resiliency of the state should also be considered
I've really enjoyed thinking about this survey and carrying it out and hope that we have managed to at least catch a glimpse of the diversity within our garden habitats and look forward to gathering a full season of data next year and beyond. If you have any suggestions on how we can improve the survey please do let us know and if you would like to try the survey yourself, send us an email and  I'll send you the record-keeping templates and protocols. You can find the complete records of the survey along with protocols, maps and habitat types here. You can access the different sheets via the blue tabs at the top of the sheet.

Useful links

Healthy food production and biodiversity at Balkan Ecology Project

Creating biodiverse community land

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