Maintaining the recovery of the formerly federally endangered Kirtland’s warbler (Setophaga kirtlandii) requires continual creation of early-successional jack pine (Pinus banksiana) habitat every ...year, which, in turn, requires a steady supply of commercial timber sales. However, dedicated Kirtland’s warbler habitat plantations are established at high stem densities (ca. 3600 trees ha−1) which can delay the production of marketable timber compared to a conventional forestry planting density (ca. 1900 trees ha−1). We used a retrospective approach to assess the impacts of tree density on Kirtland’s warbler occupancy, and an experimental approach to understand benefits and costs of pre-commercial thinning of Kirtland’s warbler habitat plantations. We observed an unexpected negative relationship between realized plantation density and maximum occupancy by Kirtland’s warbler singing males. We found that thinning of high-density jack pine planted for Kirtland’s warbler habitat resulted in increased diameter growth, increased live crown ratio, and a trend towards increased intrinsic water-use efficiency in the older age classes. These findings provide strong support for the importance of using adaptive management approaches to more rigorously evaluate the impacts of plantation spacing on Kirtland’s warbler productivity. Although increases in volume growth and timber prices following thinning are unlikely to ever recoup the costs of implementation, we argue that thinning could still be an important tool to accelerate the rate at which these stands attain marketability for the timber sales that are necessary to create a continuous supply of Kirtland’s warbler breeding habitat.
•Kirtland’s warbler occupancy did not increase with increasing stem density.•Kirtland’s warbler occupancy was influenced by stand age and habitat connectivity.•Plantations that had aged out of breeding habitat showed no evidence of stagnation.•Financial returns are unlikely to ever recoup the costs of pre-commercial thinning.
•Water-Energy-Food Nexus Index (WEFNI) was developed at watershed scale in Iran.•WEFNI was applied as an important approach to improve optimal cropping pattern.•The development of horticultural crops ...was recommended for the Shazand watershed.
The increasing demands of the population and the need for development obliged the optimal use and adaptive management of the watershed resources. Accordingly, it is necessary to adopt comprehensive measures to reach sustainable development goals. This objective can be achieved by the application of interdisciplinary and professional approaches through establishing dynamic and optimal balance in supply and demand resources. However, such important optimization approaches have been rarely practiced at the watershed scale. The present study has been therefore formulated to apply a linear water-energy-food nexus optimization for the Shazand watershed, Markazi Province, Iran. This approach was applied for planning 14 crops planted in orchard, irrigated farms, and rain-fed farms, between 2006 and 2014, and targeting water-energy-food nexus index (WEFNI) maximization. The connections among the water, energy, and food were then evaluated through determining the amount of consumption, mass productivity, and economic productivity of water and energy. The results of WEFNIs revealed that almond has the highest WEFNI with values of 0.92, 0.76, 0.76, 0.83, 0.86, 0.86, 0.87, 0.87, and 0.88. Whilst, potato with WEFNI of 0.05, 0.05, 0.05, 0.06, 0.09, 0.10 and 0.11, sugar cane with WEFNI of 0.10 and cucumber with WEFNI of 0.13 had the lowest scores and the corresponding lowest performance among the study crops. The outcomes of optimization study explained that the current situation of land use in the Shazand Watershed is unsuitable to minimize water and energy consumption and maximize benefit. The results can be used as an effective tool for designating proper soil and water resource management strategies in the region.
Woody thickening or ‘bush encroachment’ is a growing concern in savannas worldwide, and can reportedly be reversed by applying high‐intensity fires. Preliminary findings following experimental fires ...in 2010 and 2013 indicated that woody plant cover declined 1 year after high‐intensity fires, but increased after low‐intensity fires. However, the longer‐term outcomes of high‐intensity fires are largely unknown.
To establish longer‐term outcomes, we re‐assessed sites subjected to low, medium and high‐intensity fire treatments 10 years after the initial experimental fires. We compared woody vegetation structure in 2010 with that in 2020 using both ground surveys and airborne LiDAR.
Ground surveys revealed increases in the number of stems and individual shrubs (<10 m tall) over 10 years, and decreases in shrub height, with no significant differences between treatments. Large trees (≥10 m) declined by about 65% in number due to ongoing high mortality across treatments over 10 years.
LiDAR surveys revealed significant but very small differences in woody plant height and cover between treatments after 10 years. Median height was around 2 m in all treatments, and 90th percentile tree height was moderately taller in the low fire treatment. Mean canopy cover was about 55% in all treatments. The treatments therefore did not result in a meaningful reversal of woody encroachment with no discernible difference between the treatment sites after 10 years.
Synthesis and applications. The application of high‐intensity fires did not reverse woody encroachment in the longer term. In addition, the application of such treatments would be impractical at a large scale. Within a framework of strategic adaptive management, the next logical step would be to attempt a different approach. In this case, it is intended to use early or late wet season burns to increase the mortality of shrubs when they are in a more vulnerable phenological state. This study illustrates the importance of ongoing long‐term monitoring, review and adaptation for finding practical ways to achieve desired ecological outcomes.
Isifinyezo
Ukujiya kokhuni noma ‘ukwana kwehlathi’ kuwukukhathazeka okukhulayo kuma‐savanna emhlabeni wonke, futhi kubikwa ukuthi kungahlehliswa ngokubasa imililo enamandla kakhulu. Okutholwe okokuqala kulandela imililo yokuhlola ngo‐2010 kanye no‐2013 kubonise ukuthi ikhava yezitshalo ezinokhuni yehla unyaka owodwa ngemuva kwemililo enamandla kakhulu, kodwa yanda ngemuva kokusha kwemililo enamandla amancane. Kodwa‐ke, imiphumela yesikhathi eside yemililo enamandla kakhulu ayaziwa kakhulu.
Ukuze kutholwe imiphumela yesikhathi eside, siphinde sahlola izindawo ezingaphansi kokwelashwa komlilo omncane, ophkakathi kanye nophezuku ngokushisa uma sekuphele iminyaka eyishumi saqala ukuhlola. Siqhathanise ukwakheka kwezitshalo ezinokhuni ngo‐2010 nalokho ngo‐2020 sisebenzisa kokubili ukuhlola komhlaba kanye ne‐LiDAR ehamba emoyeni.
Ukuhlola okuphansi kwembula ukwanda kwenani leziqu nezihlahlana ezingazodwana (<10 m ubude) eminyakeni eyishumi, kanye nokuncipha kobude bezihlahla, kungekho mehluko omkhulu phakathi kokwelashwa. Izihlahla ezinkulu (≥10 m) zehle cishe ngo‐65% ngenani ngenxa yokufa okuphezulu okuqhubekayo phakathi kweminyaka eyishumi.
Ukuhlola kwe‐LiDAR kwembula umehluko obalulekileyo kodwa omncane kakhulu ekuphakameni kwesitshalo esinezinkuni kanye nekhava phakathi kokwelashwa ngemva kweminyaka eyishumi. Ubude obumaphakathi kwaba ngu‐2 m kukho konke ukwelashwa, futhi ukuphakama kwesihlahla esingamaphesenti ngamashumi ayisishiyagalolunye kwakubude ngokusesilinganisweni ekwelashweni komlilo ophansi. Ikhava ye‐canopy emaphakathi yayicishe ibe ngama‐55% kukho konke ukwelashwa. Ngakho‐ke ukwelapha akuzange kuholele ekubuyiselweni emuva okunengqondo kokungena kwezinkuni ngaphandle komehluko obonakalayo phakathi kwezindawo zokwelapha ngemuva kweminyaka eyishumi.
Ukuhlanganisa kanye nezicelo. Ukusetshenziswa kwemililo enamandla kakhulu akuzange kubuyisele emuva ukugxambukela kwezinkuni esikhathini eside. Ngaphezu kwalokho, ukusetshenziswa lendlela bekungeke kusebenze ngezinga elikhulu. Ngaphakathi kohlaka lwe‐Strategic Adaptive Management, isinyathelo esilandelayo esinengqondo kungaba ukuzama indlela ehlukile. Kulesi simo, kuhloswe ukuthi kusetshenziswe ukushisa kwenkathi yemvula ekuqaleni noma kwakamuva ukuze kwandiswe ukufa kwezihlahla lapho zisesimweni esisengozini kakhulu se‐phenology. Lemfundo ibonisa ukubaluleka kokuqapha okuqhubekayo kwesikhathi eside, ukubuyekezwa kanye nokuzivumelanisa nezimo ukuze kutholakale izindlela ezingoqobo zokuzuza imiphumela efiselekayo kwezemvelo.
The application of high‐intensity fires did not reverse woody encroachment in the longer term. In addition, the application of such treatments would be impractical at a large scale. Within a framework of strategic adaptive management, the next logical step would be to attempt a different approach. In this case, it is intended to use early or late wet season burns to increase the mortality of shrubs when they are in a more vulnerable phenological state. This study illustrates the importance of ongoing long‐term monitoring, review and adaptation for finding practical ways to achieve desired ecological outcomes.
Globally, collapse of ecosystems—potentially irreversible change to ecosystem structure, composition and function—imperils biodiversity, human health and well‐being. We examine the current state and ...recent trajectories of 19 ecosystems, spanning 58° of latitude across 7.7 M km2, from Australia's coral reefs to terrestrial Antarctica. Pressures from global climate change and regional human impacts, occurring as chronic ‘presses’ and/or acute ‘pulses’, drive ecosystem collapse. Ecosystem responses to 5–17 pressures were categorised as four collapse profiles—abrupt, smooth, stepped and fluctuating. The manifestation of widespread ecosystem collapse is a stark warning of the necessity to take action. We present a three‐step assessment and management framework (3As Pathway Awareness, Anticipation and Action) to aid strategic and effective mitigation to alleviate further degradation to help secure our future.
Global climate pressures and regional human impacts are causing increasing collapse of ecosystems across Australia and reaching to Antarctica. Ecosystems are experiencing multiple pressures simultaneously, either chronically (e.g. increasing air temperatures) and/or as extreme, short events (e.g. storms, fires), with their deterioration exhibiting a range of patterns. Knowing these patterns can alert conservation managers to impending collapse. We provide a new framework (the 3As) to use in conservation that focuses on preventing collapse (Awareness of ecosystem values; Anticipation of the range of pressure; Action to stop pressures), as well as guidance as to the types of conservation options available.
The present perspective summarizes and projects the results of a two-day workshop held in 2013 with the presence of 21 known disaster risk specialists from academia and practice. Faced with the ...disconnect between ever-increasing and even-accelerating disaster losses and the declared progress in disaster risk management (DRM) practice over the last eight years, the document attempts to explain the current situation and project future needs in order to increase the saliency and effect of DRM. A review of current conceptual problems and their impact on knowledge and action, of the current role of DRM in society, of governance aspects and of the notion of transformative development and its relationship to DRM is provided. The critique of current practice and understanding of disaster risk then leads to an attempt to identify key needs for the future and changes that must be introduced in order for DRM to become more mainstream and effective. Among the more central concerns, the document points to the way in which disasters are still many times seen as exogenous happenings as opposed to social constructions, product of skewed development practices. This then is reflected in much governance practice and action that are flawed. The difficulty in moving from a reactive and corrective DRM practice to a more prospective, risk avoidance practice is also highlighted.
Ecosystem management as a wicked problem DeFries, Ruth; Nagendra, Harini
Science (American Association for the Advancement of Science),
04/2017, Letnik:
356, Številka:
6335
Journal Article
Recenzirano
Ecosystems are self-regulating systems that provide societies with food, water, timber, and other resources. As demands for resources increase, management decisions are replacing self-regulating ...properties. Counter to previous technical approaches that applied simple formulas to estimate sustainable yields of single species, current research recognizes the inherent complexity of ecosystems and the inability to foresee all consequences of interventions across different spatial, temporal, and administrative scales. Ecosystem management is thus more realistically seen as a “wicked problem” that has no clear-cut solution. Approaches for addressing such problems include multisector decision-making, institutions that enable management to span across administrative boundaries, adaptive management, markets that incorporate natural capital, and collaborative processes to engage diverse stakeholders and address inequalities. Ecosystem management must avoid two traps: falsely assuming a tame solution and inaction from overwhelming complexity. An incremental approach can help to avoid these traps.
Competition for fresh water is increasing in highly populated areas especially those regions located in arid and semi-arid climates. Water uses are under scrutiny to determine the potential for water ...savings. Particularly, the agricultural sector is identified because it is the largest consumer of water. However, information is limited on the year-to-year variability of agricultural irrigation management, specifically the variability related to seasonal water availability. Remote sensing is a useful input into models to estimate actual evapotranspiration (ETa) for large irrigation districts and provides an archive of historical data. In this paper, a decade of remote sensing data are used applying the METRIC algorithm and linear interpolation to achieve ETa estimates. Inter-annual variations in seasonal ETa are related to snowpack, weather, irrigation diversions and crop data to understand the factors having an impact. It was found that consecutive (second) years of dry or wet events impacted the seasonal ETa, indicating limitations in the buffer capacity of the irrigation district. This study shows that the irrigation district is capable of buffering dry or wet events during the first year, but need to adapt during a consecutive year of extreme dry or wet weather. Additionally, cropping patterns indicate that the crop choices in the irrigation district do not change during extreme events. In contrast, irrigation diversions are influenced by prolonged dry events. The depleted fraction indicated good performance of the irrigation system, with potential for improvements in dry years. This study demonstrates the dynamic consumptive water use of an irrigation district, thereby indicating the importance for considering multiple years of data for an assessment of the agricultural sectors’ water use. Additionally, the impact of seasonal water availability gives insight on the adaptability of an irrigation district and its’ capability to cope with current and future variability in weather conditions and extreme events.
•Inter-annual variations were studied with a decade of remotely sensed ETa estimates.•ETa of a second dry year was different than a first, indicating limited capacity.•Cropping patterns and area displayed slight changes but were not distinct.•Irrigation diversions were influenced by prolonged drought.•Irrigation districts are not static but display dynamic and adaptive management.
Adaptive management (AM) is often cited as an innovative approach which could improve recovery plans for threatened species, yet real-world applications remain rare. Here, we describe an adaptive ...program for the reintroduction of a threatened amphibian in Italy. We used an adaptive approach to decide whether to use captive breeding, headstarting of tadpoles or direct translocation of eggs, with the aim of establishing a new population while minimizing the impact of harvesting from wild populations. We built a quantitative model of the system, articulated uncertainty around model parameters using probability distributions, and evaluated the benefit of learning using simulations. Following the results of simulations, we began by implementing all actions in parallel, monitoring survival of released individuals, and updating our priors using monitoring data in a Bayesian framework. Based on the updated knowledge, captive breeding and egg translocation were discontinued after the first and second year, respectively. We found little impact of harvest on the source population, so headstarting and releases are ongoing after three years. Although survival has been lower than expected, it remains within the predicted range of possible outcomes. Our experience reinforces the potential of AM for amphibian conservation. Although AM could not guarantee success, it easily scaled to our small project, it increased our efficiency in monitoring and changing actions, and ensured a safe approach against possible negative impacts. We encourage managers of amphibian recovery programs worldwide to adopt AM by following the steps we illustrate. Disseminating the results of real-world applications is the best way to fill the current implementation gap.
•Adaptive management (AM) is often advocated but rarely implemented in conservation.•We provide a real-world example of AM in the recovery of an endangered amphibian.•We used AM to choose a release strategy under parameter uncertainty.•AM scaled easily to our small project and helped us minimize risks to the species.•We recommend the adoption of AM for amphibian recovery plans.
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