I know that it has been a while since I posted anything here. The daily responsibilities and effort required for my PhD program are taking quite a toll on the time I have available for other non-phd matters (for instance curating this blog). I apologize for this and hope to post some more tutorials and discussion post in the future. However at the moment my personal research reserved 105% of my available time. But the scientific blogosphere is generally in a bit of a crisis I heard.
Anyway, today I just want to quickly share the exciting news that my MSc thesis I conducted at the Center for Macroecology, Evolution and Climate has passed scientific peer review and is now in early view in Animal Conservation. I am quite proud of this work as it represents the first lead-author paper I managed to publish that involved primary research and data collection.
Short breakdown: During my masters and also now in my PhD I am extensively working with the PREDICTS database, which is a global project aiming at collating local biodiversity estimates in different land-use systems across the entire world. The idea for this work came as I realized that many of the categories in the PREDICTS database are affected by some level of subjectivity. Local factors – such as specific land-use forms, vegetation conditions and species assemblage composition – could alter general responses of biodiversity to land use that have been generalized across larger scales. Thus the simple idea was to compare ‘PREDICTS-style’ model predictions with independent biodiversity estimates raised at the same local scale. But see abstract and paper below.
Jung et al (2016) – Local factors mediate the response of biodiversity to land use on two African mountains
Land-use change is the single biggest driver of biodiversity loss in the tropics. Biodiversity models can be useful tools to inform policymakers and conservationists of the likely response of species to anthropogenic pressures, including land-use change. However, such models generalize biodiversity responses across wide areas and many taxa, potentially missing important characteristics of particular sites or clades. Comparisons of biodiversity models with independently collected field data can help us understand the local factors that mediate broad-scale responses. We collected independent bird occurrence and abundance data along two elevational transects in Mount Kilimanjaro, Tanzania and the Taita Hills, Kenya. We estimated the local response to land use and compared our estimates with modelled local responses based on a large database of many different taxa across Africa. To identify the local factors mediating responses to land use, we compared environmental and species assemblage information between sites in the independent and African-wide datasets. Bird species richness and abundance responses to land use in the independent data followed similar trends as suggested by the African-wide biodiversity model, however the land-use classification was too coarse to capture fully the variability introduced by local agricultural management practices. A comparison of assemblage characteristics showed that the sites on Kilimanjaro and the Taita Hills had higher proportions of forest specialists in croplands compared to the Africa-wide average. Local human population density, forest cover and vegetation greenness also differed significantly between the independent and Africa-wide datasets. Biodiversity models including those variables performed better, particularly in croplands, but still could not accurately predict the magnitude of local species responses to most land uses, probably because local features of the land management are still missed. Overall, our study demonstrates that local factors mediate biodiversity responses to land use and cautions against applying biodiversity models to local contexts without prior knowledge of which factors are locally relevant.
Anthropogenic land use is one of the dominant drivers of ongoing biodiversity loss on a global scale and it has often been asked how much biodiversity loss is “too much” for sustaining ecosystem function. Our new paper in the journal Science came out last week and attempts to quantify for the first time the global biodiversity intactness within the planetary boundary framework. I am absolutely delighted to have contributed to this study and it received quite a bit of media attention so far ( https://www.altmetric.com/details/9708902 ) with a number of nice articles in the BBC and the Guardian.
In our study we calculated the Biodiversity intactness index (BII) first proposed by Scholes and Biggs (2005) for the entire world using the local biodiversity estimates from the PREDICTS project and combined them with the best available down-scaled land-use information to date. We find that many terrestrial biomes are already well beyond the proposed biodiversity planetary boundary (previously defined and set as a precautionary 10% reduction of biodiversity intactness). Unless these ongoing trends are decelerated and stopped in the near future it is likely that biodiversity loss might corroborate national and international biodiversity conservation targets, ecosystem functioning and long-term sustainable development.
- Newbold, Tim, et al. “Has land use pushed terrestrial biodiversity beyond the planetary boundary? A global assessment.” Science 353.6296 (2016): 288-291. DOI: 10.1126/science.aaf2201
Scholes, R. J., and R. Biggs. “A biodiversity intactness index.” Nature 434.7029 (2005): 45-49. DOI: 10.1038/nature03289
A quick post to highlight a new publication in this weeks issue of Current Biology. Edwards et al. went for another piece on the land-sharing/land-sparing debate and presented a very nice case study. Land-sharing is often defined as combining “sustainable” agricultural production with higher biodiversity outcomes often at the tradeoff of harvesting less and loss of natural habitats. Land-sparing on the other hand attempts to prevent remaining natural habitat from being used by humans, but instead intensify production and increase yield from other areas, thus reducing their potential for wildlife-friendly farming. They combined field work from the Choco-andres region (Taxonomic focus: Birds) with simulation models to investigate which strategy might benefit biodiversity the most. Contrary to many other previous publications they focused on phylogenetic richness (PD) rather than “species richness”. Based on landscape simulation models they could show that PD decreases steadily with greater distance to forests, which is interesting because it demonstrates that land-sharing strategies might only be successful, if sufficient amounts of natural habitat are in close proximity, that can act as source habitat for dispersing species.
According to their analysis some species seem to benefit more from land-sparing strategies than others. Specific evolutionary traits thus might be ether beneficial or detrimental for surviving in intensive human land use such as agriculture. They conclude that land-sharing might be of limited benefit without the simultaneous protection of nearby blocks of natural habitat, which can only be achieved with a co-occurring land-sharing strategy.
The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts
New article in which I am also involved. I have told the readers of the blog about the PREDICTS initiative before. Well, the open-access article describing the last stand of the database has just been released as early-view article. So if you are curious about one of the biggest databases in the world investigating impacts of anthropogenic pressures on biodiversity, please have a look. As we speak the data is used to define new quantitative indices of global biodiversity decline valid for multiple taxa (and not only vertebrates like WWF living planet index).
And here are some news from my current field work that is part of my Thesis. After spending some quiet, but exiting days in Nairobi (maybe later more about that) I finally arrived in Wundanyi, Taita Hills, where a substantial part of my work will be conducted along the CHIESA transect. Suited in the coastel area in proximity to Mombasa the Taita Hills are renown for their extraordinary bird diversity and endemic species and as such are considered to be part of the Eastern Arc Mountains Diversity hotspot. The Taita hills encompass a variety of different land-use forms, but the majority of them surely are tropical homegardens as most of the “Taita” people are subsistence farmers growing crops in the highly fertile soil of the mountain slopes. Besides homegardens there are riverine forests in the valleys, shrubland vegetation in the lower altitudes, exotic tree plantations and of course the remaining indigenous forests remaining on the Taita hills mountain tops. Every last forest part is known well and was traditionally protected by the locals as part of their culture. However in the later centuries the remaining forest area became more and more scarcer and even during my visits in some of the forest fragments with the highest biodiversity value (Chawia, Ngangao) I saw frequent signs of fuelwood and timber extraction. Clearly a lack of funding for biodiversity protection seems to be the problem, but also an economic perspective and opportunities such as ecotourism might enhance locals perception if and how these last forest parts should be protected.
My work in the Taita hills is all about birds. Specifically I am conducting avian diversity and abundance assessments along an altitudinal transect encompassing a variety of different land-use systems. Although avian assessments have been conducted in Taita many times before, they were often restricted to the forest fragments and for instance didn’t look at the bird diversity in homegardens in different altitudes. The resulting data will just be used for my thesis as validation dataset, but I am hoping that it has maybe some value on its own as well. Initial results show that especially the homegarden in Taita support quite a high diversity of birds, which is even similar to levels in the remaining forest fragments (although the community is somewhat different and biotic homogenization is likely on-going).
It can be quite challenging to conduct avian research in tropical human-dominated landscapes. Not only do you have to arrange for transport to the specific transect areas and lodging (in my case provided by the University of Helsinki Research station in Wundanyi), but also account for the frequent interruption by children and farmers asking what you are doing. Furthermore it is not an easy task to count birds in for instance a maize or sugarcane plantation due to the limited accessibility and my intention not to damage the farmers crops. Most of the farmers however happily provide access to their land and are very interested in what kind of research this “Mzungu” is doing on their farm. From my own experience here I can tell that the Taita people are very kind and it is a pleasure to work with them on their land. They are very respectful and even walking around late at night or very early in the morning seems to be no problem here (in contrast to for instance Nairobi or Mombasa).
In the end my sampling goes on quite well and much better than I expected. Although it is technically raining season and long heavy rains can be expected every day, the mornings were exceptionally dry and weather was mostly favourable for ornithological research. Generally this time of the year in East Africa is especially interesting for bird assessments as many local bird species are in their breeding plumage and nesting, but also because European migrants are often still around or on their way back to Europe (for instance I saw and heard an European Willow Warbler some days ago). Lets see what else the next weeks will have for be in terms of avian diversity.
As part of my Thesis project I have recently joined up with the researchers and interns of the PREDICTS project. PREDICTS stands for Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (yeah, fancy and down-to-the-point acronym) and is aiming to investigate the impact of various human pressures on biological diversity on a global scale. PREDICTS gets its data from contributing authors and is constantly looking for new data contributors. All contributors will become coauthors of a paper describing the database and at the end of the project the whole database will be released to the public!
If you have diversity or community composition data collected from more than one terrestrial site which are somehow influenced by humanity and are raised using a standardized methodology, then it is more than likely that we could use it. What we need is the
- Locations of sampling points, as precisely as possible
(with the coordinate system used, if possible)
- An indication of the type of land cover that each sampling point represents
(e.g. primary forest, secondary forest, intensively-farmed crop, hedgerow)
- An indication of how intensively the site is used by people
- Data on the presence / absence, or ideally a measure of abundance, of each species at each site
- The date(s) that each measurement was taken
We need more openness in terms of data sharing in conservation and ecology research! It is unbelievable that some important research data even today can go lost if for instance the original author died or his lab burned to the ground. Some might argue that it should be mandatory to share data if your research is 100% funded by public sources. Some understandable reasons that speak against data sharing after publication are for instance that you are a young emerging scientist and want to keep your hardly earned golden eggs to yourself. However this can be debated as well as data sharing not only gives you more citations, but maybe even into contact with other researchers in your field. In other cases researchers sometimes don’t want to share raw sampling data because of conservation concerns, but even here there are options to coarsen coordinates before public release.
Recent initiatives on openness in terms of ecological data sharing like https://datadryad.org/ and http://figshare.com/ already provide a splendid place where you as an Author can dump raw data from papers you wrote years ago. You can even place the raw data from your most current projects and put an embargo on the download so that the item will be released to the public for instance one year after the associated article has been published.
For my thesis I am especially looking for all kinds of African community data that has been published. We already have a lot of studies in the database, but for my project i need more data especially of less sampled taxa (insects, amphibians,…), different temporal resolutions and a greater diversity of land-use types. So especially if you have data on African species communities in any form (diversity metrics, abundance metrics, I even take occurence matrices) which were sampled in somehow anthropogenic disturbed habitats: Please contact me or wait for me to contact you 🙂
Just now a new webportal promoting the protection of roadless areas around the world opened up. Featuring a road alert ticker, a very entertaining short clip and more news about current deforestations.
Although in my opinion roads are merely a proxy for anthropogenic (agricultural) development, but they are certainly a good indicator of follow up development and literally all large-scale deforestations in the last decade are accompanied by road construction. However this mostly matters for forests and large scales. Poachers can enter a forest without cars, invasive species can spread without roads within naturally disturbed areas in forests, pollution can affect it through water, soil and air and so on. So keep in mind that just because there is no road it doesn’t mean that a particular area counts as well protected wilderness (what does this word mean anyway in the ‘Anthropocene’). Nevertheless, forest without roads are certainly worth protecting and they should be kept roadless!