Executive summary
“Best bet” Land-use Systems
Thematic reports
Impact of different land uses on biodiversity
Unique id: IDA1IQ0C
Source file: D:\Projects\ASB\ASB Country and Thematic reports\Above ground biodiversity assessmet WG\AGPartsA&B.xml
Authors: A.N. Gillison
--------------------------------------------------------------------------
This report covers the contractual requirement of ASB to the
Global Environment Facility (GEF) to meet Goal 2 “Assessment of the impact on biodiversity of different land uses” as
outlined in the aims and objectives of Phase II[1]. It also meets the broader goals of the ASB
consortium to explore the dynamic linkages among biodiversity, carbon
sequestration and productivity for human needs. The approach has been to
establish a series of ecoregional biophysical baselines to first identify and
then to evaluate, via intensive field studies, some of the key predictive
relationships among plant and animal species and functional types and the
physical environment. The size of this task required that it be tackled at two
levels: first, to identify broad distributional patterns of key plant groups
along gradients of land use at the ecoregional scale, as these are usually
closely associated with both plant and animal performance overall; and second,
to explore finer scale patterns of both plant and animal performance along an
intensive land-use gradient within a specified ecoregion. The assumption has
been that the information derived from the intensive study could reveal
indicators of biodiversity response to land use that could be extrapolated and
subsequently tested within the broader spatial ecoregional framework. Once
identified, such indicators would be examined to assess their potential use by
managers and planners in ongoing assessment and monitoring of biodiversity and
as an aid to decision support for adaptive management. While this report deals
mainly with above-ground biodiversity according to the TOR of the GEF contract,
close attention has been given as well to below-ground elements in the
intensive study in order to better understand the dynamic between biodiversity
and land use. Funding for additional survey work in
The study was conducted along a series of land-use gradients
in the Western Amazon basin,
From this point of view the study has met the needs of the
GEF TOR in that we have established an improved theoretical and empirical basis
for forecasting the impact of land use on biodoversity along defined environmental
gradients. This now has the capacity to be translated into a toolkit for
managers to rapidly assess the comparative biodiversity status quo within tropical, lowland forested and agroforested
landscapes and their land-use potential and then to use the acquired
information to select appropriate options for sustainable management. In the
course of data analyses and, at the request of the ASB social scientists, a
vegetation index (the “V” index) was derived from a minimum set of plant-based
variables known to be highly correlated with land-use type, plant and animal
richness and soil nutrient availability. Together with a species/plant
functional type-richness ratio measure, this has been incorporated into a
Policy Analysis Matrix and into a bioeconomic simulation model developed by ASB
partners. Recent surveys in Northern
Thailand and Central and
A significant finding from the survey is that in a number of cases, plant and animal richness in early fallows and in late secondary forests and agroforests (especially jungle rubber and jungle Cacao) may exceed that of nearby intact or old-growth forest. The implications from this are that, together with certain fallow systems, certain agroforests can contribute significantly to overall biodiversity at the landscape level. The study also suggests that the influence of so-called dominant fallow weeds, e.g. Chromolaena and Lantana, should be investigated more closely, as in certain circumstances they may contribute rather than detract from biodiversity and soil nutrition. Highly significant correlations between certain sets of readily measurable, plant-based attributes and above-ground carbon suggest that the rapid survey approach may be appropriate for rapid assessments of above-ground carbon, and, under certain circumstances, below-ground carbon, where this is required to estimate actual and potential rates of carbon sequestration under different land use scenarios.
The methods used in the study have also provided a new and wholly quantitative, generic technique for profiling plant and animal habitats. Initial comparisons between similar land-use types in different countries reveal relatively consistent profiles when this method is used. A testable, cost-efficient, generic tool is now available for rapidly comparing ecosystem response in different parts of the lowland tropics where, for example, in similar physical environments in which species differ, plants and animals may possess similar adaptive traits. This development underscores the generally poor predictive capacity of plant species alone and without the benefit of complementary functional types. It also highlights the importance of including the genetically-based functional component of both plants and animals in the biodiversity equation. For management, this is significant as it opens the way to characterising individuals using non-species-based methods. For example, more than one plant functional type may occur within a species and vice versa. It is clear that biodiversity assessment cannot be meaningfully implemented in isolation from other landscape facets. Because many taxa and functional types range across different land-use types, biodiversity must be assessed within the context of gradients of land-use intensity and type. The predictive models and plant-based indicators are specific only for tropical, lowland environments; further study is required before these can be developed and tested for both lowland and upland ecosystems.
Specific software was developed in the course of the project to support both potential mapping of species (DOMAIN) and field collection and analysis of data acquired using the rapid survey vegetation proforma (PFAPro). The DOMAIN mapping software originally developed by CSIRO has been re-compiled to run under a user-friendly Windows environment. Both software programs have been extensively used in training programs for above-ground biodiversity assessment in the three ecoregions. They are available gratis via the CIFOR web page and registered downloads of the DOMAIN program have been recorded from 45 countries since its release in August 1997. Although the PFAPro package has been used widely in both training and field operations, it is still in the beta-testing phase and new upgrades, including multilingual versions, are planned pending adequate funding.
Apart from the development of new biodiversity assessment survey tools, a significant outcome of the study thus far is the evident need for improved coordination of multidisciplinary field activities, in particular, the co-location of study sites. Despite early setbacks in planning and coordination of Phases I and II, the ASB program has now developed a very robust and productive research structure where devolution of research responsibility to in-country teams and partners is proving highly profitable. It is very evident from the dynamism inherent in almost all phases of land use in tropical forested lands that there is no one set of universal ‘best bet’ alternatives to slash and burn. Phase II has clearly shown that, at best, simple, generic tools based on sound scientific principles are likely to be more appropriate for managers to rapidly and cost-effectively assess and monitor the natural resource base than ‘one-hit’ land-use prescriptions developed in areas remote from the situation at hand. In a climate of largely unpredictable and stochastic biophysical and economic events, it will be necessary to have access to such tools in order to assess, compare, analyse and implement management with a greater awareness of biodiversity impact and economic outcomes. Research that targets such needs will produce a more efficient ‘bang for the buck’ by allowing managers and land owners to adapt to changing circumstance and to better control their livelihoods.
Future needs include a re-definition of research targets and a careful examination of knowledge gaps. The results of the above-ground biodiversity study suggest the methodology is now reasonably well worked out and requires further testing in upland and coastal environments as well as wetlands. While much more remains to be studied in the context of biodiversity and profitability, the recent improvements in research coordination indicate the real future challenge for developing sustainable options for management lies in understanding the dynamic linkages between biophysical and socio-economic elements of land use in forested and agroforested landscapes. Provided we can gain some understanding of these processes, this will open the way to appropriate policy intervention.